HP 4550 Service Manual
HP 4550 - Color LaserJet Laser Printer Manual
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HP 4550 manual content summary:
- HP 4550 | Service Manual - Page 1
hp color LaserJet 4550/4500 series service manual achieve - HP 4550 | Service Manual - Page 2
- HP 4550 | Service Manual - Page 3
HP Color LaserJet 4550/4550N/4550DN/ 4550HDN Printer and HP Color LaserJet 4500/ 4500 N/4500 DN Printer Service Manual - HP 4550 | Service Manual - Page 4
Part number: C7085-90921 First Edition, October 2000 Warranty The information contained in this document is subject to change without notice. Hewlett-Packard STAR is a U.S. registered service mark of the United States Environmental .'s check-standard trademark for color. PostScript is a trademark - HP 4550 | Service Manual - Page 5
This is a combined Service Manual for both the HP Color LaserJet 4500 series printer and the HP Color LaserJet 4550 series printer. The HP Color LaserJet 4550 series printer shares most characteristics of the HP Color LaserJet 4500 series printer, except where stated. This manual uses the following - HP 4550 | Service Manual - Page 6
iv - HP 4550 | Service Manual - Page 7
36 Safety information 37 2 Service approach Service approach 40 Parts and supplies 41 Warranty statement 44 3 Installation and configuration Unpack the printer 48 Installation 50 Connecting to a network 64 Enhanced I/O (EIO) configuration 67 Printer drivers 69 Network configuration 70 - HP 4550 | Service Manual - Page 8
assemblies 195 Internal assemblies 200 7 Troubleshooting Introduction 211 Troubleshooting process 212 Printer error troubleshooting 217 Paper path troubleshooting 237 Image formation troubleshooting 243 HP ColorSmart II 246 Matching colors 247 Four-color printing (CMYK 248 Image defects - HP 4550 | Service Manual - Page 9
Color LaserJet 4500 (shown with 500-sheet paper feeder and duplex unit) . . . . .26 Figure 1-8 Rear view, HP Color LaserJet 4550 (shown with 500-sheet paper feeder and duplex unit) . . . . .27 Figure 3-1 Package contents 48 Figure 3-2 Parallel cable with a "C" connector 58 Figure 4-1 Imaging drum - HP 4550 | Service Manual - Page 10
6-14 Laser/scanner assembly HP Color LaserJet 4500 and HP Color LaserJet 4550 printers 174 Figure 6-33 High-voltage power supply removal and replacement (older version HP Color LaserJet 4500 printers 175 Figure 6-34 Drum 6-47 Fuser motor removal and replacement (1 of 2 185 Figure 6-48 Fuser motor - HP 4550 | Service Manual - Page 11
map 293 Figure 7-18 HP Color LaserJet 4500 series Service menu map 294 Figure 7-19 HP Color LaserJet 4550 series Service menu map 295 Figure 7-20 Registration page 298 Figure 7-21 Location of the engine test button 306 Figure 7-22 Sensor locations 308 Figure 7-23 Printer solenoids and clutches - HP 4550 | Service Manual - Page 12
Figure 7-40 Location of duplexer and 500-sheet paper feeder connectors 320 Figure 7-41 500-sheet feeder wiring diagram 321 Figure 8-1 Assembly location diagram (1 of 2 330 Figure 8-2 Assembly location diagram (2 of 2 331 Figure 8-3 PCB locations 332 Figure 8-4 External covers, panels, etc 334 - HP 4550 | Service Manual - Page 13
items 142 Table 7-1 Pre-troubleshooting checklist 213 Table 7-2 Alphabetical printer error messages 217 Table 7-3 Numerical printer error messages 226 Table 7-4 HP Color LaserJet 4500 jam locations and associated error messages 239 Table 7-5 HP Color LaserJet 4550 jam locations and associated - HP 4550 | Service Manual - Page 14
7-42 Miscellaneous parts 314 Table 7-43 Imaging drum connector 315 Table 7-44 Fuse F1 and CB101 location 317 Table 7-45 110-volt fusing assembly 317 Table 8-1 Consumables, accessories, and supplies 325 Table 8-2 Types of screws 328 Table 8-3 PCB assembly 333 Table 8-4 Printer cover and door - HP 4550 | Service Manual - Page 15
29 Non-supported media 30 Printing on special media 31 Environmental Product Stewardship Program 34 Regulatory statements 36 HP Color LaserJet 4500 36 HP Color LaserJet 4550 36 Safety information 37 Laser safety statement 37 Material Safety Data Sheet 37 Toner safety 37 Laser statement for - HP 4550 | Service Manual - Page 16
HP Color LaserJet 4500 family printers 1 HP Color LaserJet 4500 and 4500 N printers 2 HP Color LaserJet 4500 DN printer The HP LaserJet 4550 printer family pictured in Figure 1-2 has four models. The HP LaserJet 4550 printer is the base model; it includes 64 MB of RAM. The HP LaserJet 4550N - HP 4550 | Service Manual - Page 17
) (included with the HP Color LaserJet 4500 N and 4500 DN printers) Optional HP JetDirect 610N print server (network card) (included with the HP Color LaserJet 4550N, 4550DN and 4550HDN printers) HP Color LaserJet 4550 series: Infrared receiver port HP Color LaserJet 4550 series: Embedded Web - HP 4550 | Service Manual - Page 18
wit the HP Color LaserJet 4550HDN printer). CAUTION: The HP Color LaserJet 4500 series uses 100-pin, non-parity, SDRAM DIMMs. The HP Color LaserJet 4550 series uses 168-pin, non-parity, synchronous DRAM DIMMs. Extended Data Output (EDO) DIMMs are not supported. 16 Printer description C7085 - HP 4550 | Service Manual - Page 19
the rear output bin is in reverse order, facing up.) Printer-language support HP Color LaserJet 4500 series: HP PCL5c PostScript™ Emulation Automatic language switching HP Color LaserJet 4550 series: HP PCL 5c HP PCL 6 PostScript™ 3 Emulation Automatic language switching Paper sizes - HP 4550 | Service Manual - Page 20
N C4089A HP Color LaserJet 4500 DN C4094A HP Color LaserJet 4550 C7085A HP Color LaserJet 4550N C7086A HP Color LaserJet 4550DN C7087A HP Color LaserJet 4550HDN C7088A Two versions of the HP Color LaserJet 4500 series printers are available. Before servicing the printer or ordering parts - HP 4550 | Service Manual - Page 21
also contain power rating and regulatory information as shown in Figure 1-4. Converting the voltage on the printer can damage the printer. Do not use any voltage other than the operating voltage. Any attempt to convert operating voltages will void the product warranty (for example, attempting - HP 4550 | Service Manual - Page 22
): • for the HP Color LaserJet 4500 and 4500N, the surface must support 51 kg (112 lb) • for the HP Color LaserJet 4500DN, the surface must support 77 kg (169 lb) • for the HP Color LaserJet 4550 and 4550N, the surface must support 51 kg (112 lb) • for the HP Color LaserJet 4550DN and 4550HDN, the - HP 4550 | Service Manual - Page 23
Space requirements The printer must have the following amounts of space above and around it. Figure 1-5 Space requirements 1 Top view 2 Side view C7085-90921 Chapter 1 Printer description 21 - HP 4550 | Service Manual - Page 24
capacity for typical 4550: 10.2 A at 120 V product 4500: 7.1 A at 220 V 4550: 5.1 A at 220 V *When the printer is in standby (off) mode, it continues to consume a minimal amount of energy. This information is preliminary and might not be current. Please see http://www.hp.com/support/ lj4550 for - HP 4550 | Service Manual - Page 25
1-6 Printer dimensions HP Color LaserJet 4500, 4500N Height 395 mm (15.6 inches) Width 500 mm (19.7 inches) Depth 559 mm (22 inches) Weight 57 kg (125 lb) HP Color LaserJet 4500 DN 578 mm (22.8 inches) 500 mm (19.7 inches) 709 mm (27.9 inches) 75 kg (165 lb) HP Color LaserJet 4550, 4500N - HP 4550 | Service Manual - Page 26
Note This product emits a sound intensity level, LWAd, at 6.4 bel during printing. Do not place the printer in close proximity to users. Maximum duty cycle is 35,000 pages per month. 24 Printer description C7085-90921 - HP 4550 | Service Manual - Page 27
HP Color LaserJet 4500 and HP Color LaserJet 4550 (shown with 500-sheet paper feeder and duplex unit) 1 Top output bin 2 Printer control panel 3 Power switch (standby button) 4 Duplex unit drawer (optional on 4500, 4500N, 4550 and 4550N models) 5 Tray 3 (500-sheet tray; optional on 4500, 4500N, 4550 - HP 4550 | Service Manual - Page 28
4 Figure 1-7 Rear view, HP Color LaserJet 4500 (shown with 500-sheet paper feeder and duplex unit) 1 Rear door (fuser access) 2 Rear output bin door 3 Cover for duplex unit 4 Power receptacle for duplex unit 5 Duplex unit power cord to the printer 6 Printer power receptacle 7 EIO slots 8 Parallel - HP 4550 | Service Manual - Page 29
4 Figure 1-8 Rear view, HP Color LaserJet 4550 (shown with 500-sheet paper feeder and duplex unit) 1 Rear door (fuser access) 2 Rear output bin door 3 Cover for duplex unit 4 Power receptacle for duplex unit 5 Duplex unit power cord to the printer 6 Printer power receptacle 7 EIO slots 8 Parallel - HP 4550 | Service Manual - Page 30
many types of paper and other print media with this printer. This section provides guidelines and specifications for selecting and using the HP LaserJet Family Print Media Guide can cause problems that require service. This service is not covered by the Hewlett-Packard warranty or service agreements - HP 4550 | Service Manual - Page 31
media weights and sizes Table 1-8 shows the media types and sizes supported by the printer and the printer accessories. Table 1-8 Supported media specifications Tray Tray 1 Supported media Media specifications Capacity Paper Single-sided: 150 sheets of 75 g/m2 A4/Letter (20 lb) paper - HP 4550 | Service Manual - Page 32
or printer. Do not use paper with a watermark if you are printing solid patterns. Do not duplex on glossy paper. Doing so will result in jams and print-quality problems. Do not use transparencies that are not specified for use with HP Color LaserJet printers. 30 Printer description - HP 4550 | Service Manual - Page 33
transparencies can become overheated and melt, causing serious damage to your printer. Hewlett-Packard recommends using HP Color LaserJet Transparencies with this printer. HP products are designed to work together for optimum printing results. Note Table 1-9 Printing on transparencies Description - HP 4550 | Service Manual - Page 34
supported paper types and sizes. Envelopes Envelopes can only be printed from Tray 1. For information about loading envelopes, see the section in the online user guide , Hewlett-Packard recommends configuring Tray 1 as a cassette and setting the tray's media type to LABELS in the printer control - HP 4550 | Service Manual - Page 35
paper This printer supports the use of recycled paper. Recycled paper must meet the same specifications as standard paper; refer to the HP LaserJet Family Print Media Guide, available through HP Direct. See the online user guide for ordering information. Hewlett-Packard recommends that recycled - HP 4550 | Service Manual - Page 36
and Service Office for further instructions. HP recycling program information: This HP LaserJet printer also contributes to protecting the environment in the following ways: HP LaserJet printing supplies-In many countries, this product's printing supplies (e.g., toner cartridge, drum, fuser) can - HP 4550 | Service Manual - Page 37
LaserJet Toner Cartridge and Consumables Recycling Program. Paper-This printer is suited for the use of recycled papers (according to DIN 19 309) when the paper meets the guidelines outlined in the HP LaserJet Family Print Media Guide. For downloadable manuals, go to http://www.hp.com/support - HP 4550 | Service Manual - Page 38
HP Color LaserJet 4500 User Guide, or go to http://www.hp.com/cposupport/prodhome/ hpcolorlas7857.html. HP Color LaserJet 4550 For the most current regulatory statements regarding the HP Color LaserJet 4550 series, please see the HP Color LaserJet 4550 User Guide, or go to http://www.hp.com/support - HP 4550 | Service Manual - Page 39
see support information in this guide for appropriate phone numbers and information. Toner safety Hewlett-Packard encourages responsible disposal of HP LaserJet printer consumable items through its Environmental Collection Program. For details on this program, see the recycling instruction guide - HP 4550 | Service Manual - Page 40
Laser Apparat HP LaserJet 4500, 4550-laserkirjoitin on käyttäjän kannalta turvallinen luokan 1 laserlaite. Normaalissa käytössä kirjoittimen suojakotelointi estää lasers ävän laserdiodin säteilyominaisuuksista: Aallonpituus 770-795 nm Teho 5 mW Luokan 3B laser 38 Printer description C7085-90921 - HP 4550 | Service Manual - Page 41
program 42 Consumables 42 World Wide Web 42 HP Service Parts Information Compact Disc 42 HP Support Assistant Compact Disc 42 Ordering related documentation and software 43 Warranty statement 44 Hewlett-Packard warranty statement 44 Onsite service agreements 45 C7085-90921 Chapter - HP 4550 | Service Manual - Page 42
Step 3 Troubleshoot the problem using the procedures in Chapter 7. Once a faulty part is located, the printer can usually be repaired at the assembly level by replacing field replaceable units (FRUs). Some mechanical assemblies might need to be repaired at the subassembly level. Hewlett-Packard does - HP 4550 | Service Manual - Page 43
found in Chapter 8 of this manual. Replacement parts can be ordered from HP's Commercial Support Services Organization-Americas (CSSO-A) or HP's Commercial Support Services Organization-Europe (CSSO-E). Use only accessories specifically designed for this printer. Accessories can be ordered from an - HP 4550 | Service Manual - Page 44
(CSSO-A) or Commercial Support Services Organization-Europe (CSSO-E). Consumables Paper and toner cartridges can be ordered directly from Hewlett-Packard. See Chapter 8 for ordering information. World Wide Web Printer drivers, updated HP printer software, and product and support information can be - HP 4550 | Service Manual - Page 45
X HP Color LaserJet 4550/4500 5963-7921 X Series Quick Reference Service Guide HP LaserJet 4550/4500 C7085-90921 X X Series Service Manual HP Color LaserJet 4550/4500 C7085-60102 X X Series Printer Service and Support CD-ROM HP Color LaserJet 4550 Series Printer Online User Guide C7085 - HP 4550 | Service Manual - Page 46
statement Hewlett-Packard warranty statement HP Color LaserJet 4500,1 year limited warranty 4500 N, 4500 DN Printer and 4550/4550N/4550DN/4550HDN Printer 1 HP warrants HP hardware, accessories and supplies against defects in materials and workmanship for the period specified above. If HP receives - HP 4550 | Service Manual - Page 47
ensure longevity of your HP LaserJet printer, HP provides the following: Onsite service agreements To provide you with the support level best suited to your system usage and support budget, HP has onsite service agreements with three response times: Priority Onsite Service is designed for production - HP 4550 | Service Manual - Page 48
46 Service approach C7085-90921 - HP 4550 | Service Manual - Page 49
cord 50 Installing the toner cartridges-for older version HP Color LaserJet 4500 printers 51 Installing the toner cartridges-for newer version HP Color LaserJet 4500 and HP Color LaserJet 4550 printers 55 Installing the imaging drum 57 Using the parallel cable 58 Selecting the display language - HP 4550 | Service Manual - Page 50
Parallel cable (only included with the HP Color LaserJet 4500 and 4550 base model printer) 6 Imaging drum 7 Four toner cartridges: cyan (C), magenta (M), yellow (Y), and black (K) 8 Tray 3 (500-sheet paper feeder, included only with the HP Color LaserJet 4500DN, 4550DN and 4550HDN printers) 9 Duplex - HP 4550 | Service Manual - Page 51
77 kg (169 lb), and must support all four corners of the 500-sheet paper feeder (serves as printer base). 2 Place the 500-sheet feeder in the prepared location. CAUTION Avoid bending the guide pins while assembling the printer. 3 Using the guide pins for proper alignment, carefully assemble the - HP 4550 | Service Manual - Page 52
button is out (standby mode). 3 Locate the power cord on the back side of the printer for the HP Color LaserJet 4500, 4500N, 4550 and 4550N printers or on the duplex unit for the HP Color LaserJet 4500DN, 4550DN and 4550HDN printers. Connect the power cord to the power receptacle on the back of the - HP 4550 | Service Manual - Page 53
HP Color LaserJet 4500 printers Note The following instructions are for older versions of the 4500 series printers (see page 140 to determine which version of the printer you have). See page 55 for instructions for installing toner cartridges in newer version 4500 series and 4550 series printers - HP 4550 | Service Manual - Page 54
that partially covers the cartridge slot. The correct toner color is shown on the flap. CAUTION Do not shake the toner cartridges after removing them from the packaging. 5 Remove the cyan toner cartridge from the bag. Gently rotate the 5 toner cartridge from side to side to redistribute the - HP 4550 | Service Manual - Page 55
, the toner is the wrong color for that cartridge slot. 9 Hold the toner cartridge so that the arrow on the right side of the 9 cartridge (the control panel side of the printer) points straight down. 10 Slide the toner cartridge down into the slot until the cartridge stops. 11 Rotate the toner - HP 4550 | Service Manual - Page 56
press [GO]. Wait while the printer runs an internal color calibration. The calibration takes a few minutes. When the printer is ready, the control panel displays: READY. CAUTION If you need to ship the printer, remove the toner cartridges and 15 imaging drum before shipping. 54 Installation and - HP 4550 | Service Manual - Page 57
5 6 C7085-90921 Installing the toner cartridges-for newer version HP Color LaserJet 4500 and HP Color LaserJet 4550 printers Note The following instructions are for newer versions of the 4500 series and 4550 series printers (see page 140 to determine which version of the printer you have). See page - HP 4550 | Service Manual - Page 58
stops. Note If the cartridge does not slide easily into the slot, ensure that you have the right color cartridge for that slot. 8 Rotate the toner cartridge toward the back of the printer (within the cartridge slot) until the cartridge clicks in place. 8 9 Lower the flap to partially cover the - HP 4550 | Service Manual - Page 59
upper drawer shut. Wait while the printer runs an internal color calibration. The calibration takes a few minutes. When the printer is ready, the control panel displays READY. CAUTION 3 If you need to ship the printer, remove the toner cartridges and imaging drum before shipping. 4 C7085-90921 - HP 4550 | Service Manual - Page 60
ft) in length. The cable (HP part number C2946A) is included with the HP Color LaserJet 4500 printer and the 4550 printer. It must be purchased separately for the HP Color LaserJet 4500N, 4500DN, 4550N, 4550DN and 4550HDN printers. Figure 3-2 Parallel cable with a "C" connector Parallel interface - HP 4550 | Service Manual - Page 61
standby mode. Turn off the computer. 2 Plug the parallel cable into the printer's parallel port until it snaps into place. 3 Plug the other end of the parallel cable into the computer. Tighten the screws on the parallel cable to secure the cable to the computer. 2 4 Turn the computer on and then - HP 4550 | Service Manual - Page 62
interface, use a 10-meter (30 ft.) parallel cable (IEEE-1284 compliant) with a 25-pin DB male 3 DATA 4 DATA 5 DATA 6 DATA 7 nACKNLG BUSY CALL (PE) SELECT NAutoFd O VDC (GND) nFAULT nSe/In nINIT PERIPHLH N.C. Printer Pin # 15 6 7 8 9 10 11 12 13 3 1 5 2 17 19 - 35 4 16 14 36 18 Computer Port - HP 4550 | Service Manual - Page 63
7-2 on page 217 if an error message appears. 3 Note If the control panel does not display the message in the language you selected, press the printer standby button and repeat the instructions for changing the display language. 4 C7085-90921 Chapter 3 Installation and configuration 61 - HP 4550 | Service Manual - Page 64
operation Print a configuration page to ensure that the printer is working properly. 1 On the control panel, press [MENU] until INFORMATION , the configuration page prints. If it does not print, see the "Troubleshooting flowchart" on page 213. 3 4 62 Installation and configuration C7085-90921 - HP 4550 | Service Manual - Page 65
setting is one hour. The instructions below explain how to change the time setting and how to turn PowerSave OFF. 1 On the control panel, press [MENU] until CONFIGURATION MENU appears on the control panel display. 2 2 Press [ITEM] until POWERSAVE=1 HR * appears on the HP Color LaserJet 4500, or - HP 4550 | Service Manual - Page 66
, but not both at the same time. See the instructions that follow to connect one or more network cables to the printer. Connecting to a LocalTalk network (J3111A only) Plug the end of your DIN-8 cable into the LocalTalk port on the HP JetDirect print server. Attach the other end to the network. Note - HP 4550 | Service Manual - Page 67
the 10Base-2 connection are not included with the printer. They must be purchased separately. 3 Connect the BNC "T" connector to the BNC port on the HP JetDirect print server. 3 Note The HP JetDirect J3111A print server supports one Ethernet cable connection at a time. BNC port C7085-90921 - HP 4550 | Service Manual - Page 68
network Plug the connector of your unshielded twisted-pair cable into the RJ-45 port. The other end of the cable should be attached to the network. Note The HP JetDirect print server supports one Ethernet cable connection at a time. HP Color LaserJet 4500 RJ-45 (10BaseT or 10/100Base-TX) connection - HP 4550 | Service Manual - Page 69
user guide.) Installation of cards and network configuration should be performed by a network administrator. Note The HP Color LaserJet 4550 series printer supports the optional 5 GB hard disk drive (included with the HP Color LaserJet 4550HDN printer). The HP Color LaserJet 4500 series printer - HP 4550 | Service Manual - Page 70
to print through a LocalTalk interface, refer to the printer's getting started guide and the HP JetDirect Print Server Software Installation Guide. CPU The HP Color LaserJet 4500 formatter PCB incorporates a 133-MHz RISC processor. The HP Color LaserJet 4550 formatter PCB incorporates a 200-MHz RISC - HP 4550 | Service Manual - Page 71
are Smooth and Details. HP ColorSmart II default settings will produce optimum results for most color printing needs. However, you can also manually adjust color settings through the printer driver's Vivid Color and Screen Match color control options. See the printer driver's online Help for details - HP 4550 | Service Manual - Page 72
a complete list of supported networks and for instructions on configuring network parameters from software such as HP JetAdmin and HP Web JetAdmin, see the HP JetDirect Print Server Software Installation Guide. The guide comes on the CD-ROM with printers in which an HP JetDirect 600N print server - HP 4550 | Service Manual - Page 73
printer mode. For more information, see the HP JetDirect Print Server Software Installation Guide. Windows 3.1, Windows 95, and Windows NT 3.51 and 4.0 networks For Windows 3.1 and Windows 95 networks, HP JetAdmin software works as a Windows application and supports native Novell Directory Services - HP 4550 | Service Manual - Page 74
Warp Server networks For IBM OS/2 LAN Server and Warp Server Networks, HP JetAdmin software supports the Data Link Control (DLC) environment. Depending on the number of network printers and type of printer driver, when using virtual memory, improved performance might be realized by increasing server - HP 4550 | Service Manual - Page 75
Utility for Macintosh, or an ASCII escape sequence to perform this procedure. For instructions on locking the printer control panel using either the HP JetAdmin software or the HP LaserJet Utility for Macintosh, see the online Help for these utilities. C7085-90921 Chapter 3 Installation and - HP 4550 | Service Manual - Page 76
menus-and you can even lock the [CANCEL JOB] key. When the printer control panel is locked, unauthorized users who try to change settings at the ASCII escape sequence. For instructions about locking the control panel by using either HP JetAdmin software or the HP LaserJet Utility for Macintosh, go - HP 4550 | Service Manual - Page 77
. The commands must also be sent to the printer by using a DOS COPY command or an ASCII file download utility. The PJL Technical Reference Manual is located on CD-ROM, part number 5961-0976. Order a copy of this manual from the HP website: http://www.hp.com. In the following examples, EC represents - HP 4550 | Service Manual - Page 78
76 Installation and configuration C7085-90921 - HP 4550 | Service Manual - Page 79
items 85 Cleaning the toner density sensor 85 Replacing the toner cartridges 86 Replacing the imaging drum 88 Replacing the transfer kit 89 Replacing the fuser kit 92 Replacing the paper rollers 94 DIMM configuration 98 Adding memory 98 C7085-90921 Chapter 4 Printer maintenance 77 - HP 4550 | Service Manual - Page 80
. DO NOT TOUCH the transfer roller with your fingers. Fuser Use a water-dampened, lint-free cloth. Cleaning spilled toner Defective toner cartridges can develop leaks. Also, after a paper jam has occurred, some toner might remain on the rollers and guides inside the printer. The pages that print - HP 4550 | Service Manual - Page 81
tray and paper transport assembly" on page 204). To remove the toner catch tray, pull downward on the tab and slide the tray out of the rear of the printer. To remove the transport assembly, remove the one screw (shown in Figure 6-69 on page 204) and then slide the assembly to the - HP 4550 | Service Manual - Page 82
occurred. The following guidelines will help determine drum life: An "image" is a layer of toner. An A-4/Letter-size color page printed on one side contains four A-4/Letter images, one for each color (CMYK). A duplexed sheet counts as two pages. In color duplex mode (printing on both sides of - HP 4550 | Service Manual - Page 83
0 Pages/Drum (K) 1 2 5 10 15 20 2000 Pages/job A-4 simplex monochrome A-4 duplex monochrome A-4 simplex color A4 duplex color Imaging drum life Note When printing black pages, there is a wider range of variation in pages/drum. The drum - HP 4550 | Service Manual - Page 84
The following graph shows the drum life for printing in Letter and Legal formats: Engine, total page count 45000 40000 35000 30000 25000 20000 15000 10000 5000 0 0 4 8 12 16 20 24 Pages/job 4-color simplex Letter 4-color duplex Letter Monocolor simplex Letter Monocolor duplex Letter 4- - HP 4550 | Service Manual - Page 85
of individual toner colors. Page counts are only estimations; usage conditions and print patterns cause results to vary. Hewlett-Packard recommends the use of HP products in this printer. Use of non-HP products can cause problems the require service not covered by the Hewlett-Packard warranty or - HP 4550 | Service Manual - Page 86
Figure 4-3 illustrates the location of each consumable item. 1 4 2 3 5 7 6 Figure 4-3 Location of consumables 1 Toner cartridges 2 Imaging drum cartridge 3 Intermediate transfer belt 4 Transfer roller 5 Air filters 6 Fuser 7 Paper feed and separation rollers 84 Printer maintenance C7085-90921 - HP 4550 | Service Manual - Page 87
and remove the cleaning brush mounted inside. 2 Open the drum drawer and remove the imaging drum using the blue handle. 3 Using the cleaning brush, remove all dust and toner particles from the sensor as illustrated. 3 4 Replace the imaging drum. 4 C7085-90921 Chapter 4 Printer maintenance 85 - HP 4550 | Service Manual - Page 88
can indicate that one or more toner colors are out. 1 With the printer turned on and warmed up, push the dark gray release button on the side of the printer ([1]) and open the printer's top cover ([2]). 2 Note If you need to replace a toner cartridge and the TONER CMYK LOW or TONER CMYK OUT messages - HP 4550 | Service Manual - Page 89
not fit in the notch when you insert the toner cartridge, the toner is the wrong color for that cartridge slot. 5 Slide the toner cartridge down into the slot until the cartridge stops. 5 6 Rotate the toner cartridge toward the back of the printer (within the cartridge slot) until the cartridge - HP 4550 | Service Manual - Page 90
1 Replacing the imaging drum Replace the imaging drum when the printer control panel displays: REPLACE DRUM KIT. 1 Open the drum drawer and remove the used imaging drum. 2 Locate the new imaging drum. Align it over the drawer so that the arrow on top points to the rear of the printer, and the blue - HP 4550 | Service Manual - Page 91
Replacing the transfer kit Replace the transfer kit when the printer control panel displays: TRANSFER KIT OUT REPLACE KIT. The transfer kit consists of an intermediate transfer belt (ITB), a transfer roller, two air filters, and a hand wipe. 1 Open the ITB drawer. Remove the used transfer belt by - HP 4550 | Service Manual - Page 92
bag. Align the blue pins that are on both sides of the new transfer belt with the blue slots in the drawer. Then slide the transfer belt down into place. Close the ITB drawer. 7 8 To reset the printer for the new transfer kit, push [MENU] on the control panel until RESETS MENU appears in the - HP 4550 | Service Manual - Page 93
[ITEM] until TRANSFER KIT SELECT IF DONE appears in the control panel display. Then press [SELECT]. 10 To replace the air filters, turn the printer off and wait 10 minutes for the fans to stop running. Unplug the power cord and open the upper rear door of the printer. If the printer has a duplex - HP 4550 | Service Manual - Page 94
1 Replacing the fuser kit Replace the fuser kit when the printer control panel displays: FUSER LIFE OUT REPLACE KIT. The fuser kit contains one fuser, four paper rollers, and a hand wipe. WARNING! To prevent possible burns, be sure the power cord is unplugged and that the printer has cooled for - HP 4550 | Service Manual - Page 95
using the finger holds. Holding the new fuser by the finger holds, slide the fuser into the printer. CAUTION The blue latches will lock only if the fuser is installed. 6 8 Lock the fuser in place by rotating the two blue latches down. Reconnect the support straps to the upper rear door. 7 8 C7085 - HP 4550 | Service Manual - Page 96
1 Replacing the paper rollers 1 Remove Tray 2 from the front of the printer. 2 On Tray 2, locate the paper roller and the cover next to the roller. 3 Squeeze the The feed roller has a D-shaped hub and the separation roller has a round-shaped hub. 3 4 94 Printer maintenance C7085-90921 - HP 4550 | Service Manual - Page 97
roller on Tray 2. Slide the new roller onto the 5 spindle until the roller clicks into place. 6 Close the cover. 7 Inside the tray cavity on the printer, locate the paper roller in the top of the tray cavity. 8 Squeeze the blue tabs on the roller and remove the old paper roller from - HP 4550 | Service Manual - Page 98
paper roller in the tray cavity for Tray 3 in the opposite direction from the paper roller in the other tray cavity. 10 11 12 96 Printer maintenance C7085-90921 - HP 4550 | Service Manual - Page 99
control panel displays READY, reset the printer for the new fuser kit and push [MENU] on the control panel until RESET MENU appears. 14 Press [ITEM] until NEW FUSER KIT, SELECT IF DONE appears. Then press [SELECT]. 15 Press [GO] to return the printer to READY. 14 15 C7085-90921 Chapter - HP 4550 | Service Manual - Page 100
guide for installation instructions. Figure 4-4 Removing the formatter board CAUTION Do not attempt to remove the DIMM in slot #4 (see Figure 4-5) of the HP Color LaserJet 4500 printer, or the DIMM in slot #3 (see Figure 4-6) of the HP Color LaserJet 4550 printer. This DIMM is part of the printer - HP 4550 | Service Manual - Page 101
in slot #3. CAUTION The HP Color LaserJet 4500 printer uses 100-pin, non-parity, synchronous SDRAM DIMMs. The HP Color LaserJet 4550 printer uses 168-pin, non-parity, synchronous DRAM DIMMs; EDO DIMMs are not supported in either the HP Color LaserJet 4500 printer or the 4550 printer. To ensure you - HP 4550 | Service Manual - Page 102
memory (NVRAM) The printer uses NVRAM to store I/O and information on the print environment's configuration. The contents of NVRAM are retained when the printer is deactivated or disconnected. There is one NVRAM on the formatter and one on the DC controller. 100 Printer maintenance C7085-90921 - HP 4550 | Service Manual - Page 103
Image formation 104 Primary charge 105 Laser exposure 106 Development 106 Transfer 107 Waste toner cleaning 109 Fusing 110 Toner density 111 Mechanical system 112 Photosensitive drum cartridge 112 Intermediate transfer belt 113 Toner carousel 118 Laser/scanner operation 120 Paper path - HP 4550 | Service Manual - Page 104
of operation and the functional overview for HP Color LaserJet 4500 series and 4550 series printers. It provides the service representative with an understanding of the printing process. This chapter is also the course material for the Service Authorization class and discusses the following printing - HP 4550 | Service Manual - Page 105
HP LaserJet 4500 series and 4550 series printer LASER/SCANNER SYSTEM Scanning mirror Laser diode BD circuit Scanner motor Photosensitive drum Developing unit Primary IMAGE charging roller FORMATION Cleaner unit SYSTEM ITB cleaning roller Intermediate transfer belt Secondary transfer - HP 4550 | Service Manual - Page 106
is the central hub of the printer. During image formation, the color image is created. The image formation system consists of the following imaging units: photosensitive drum cartridge carousel, laser/scanner toner cartridges ITB unit secondary transfer roller (see Figure 5-2) A detailed - HP 4550 | Service Manual - Page 107
's surface, an AC bias is also applied. The charge voltage on the drum surface ranges from approximately -700 V to -500 V. With the large negative charge on the drum surface, an equal positive charge forms below the photoconductive material. Figure 5-3 Primary charge C7085-90921 Chapter 5 Theory - HP 4550 | Service Manual - Page 108
in position, a negative charge is applied to the toner particles. As the developer sleeve and drum rotate past one another, the toner particles are drawn to the drum's surface. Areas of the drum's surface that are exposed to the laser attract and hold the toner while the unexposed areas repel the - HP 4550 | Service Manual - Page 109
and then from the ITB to the paper (secondary transfer). Primary transfer The ITB has a primary transfer roller that provides a positive bias that pulls the toner image from the drum to the ITB. This process is repeated four times (one time for each toner cartridge). The positive bias applied by the - HP 4550 | Service Manual - Page 110
roller, it passes over the charge eliminator. The charge eliminator removes any positive charge on the media that came from the secondary transfer roller. The elimination of positive charges decreases adhesion of the paper to the belt and allows for better separation. Figure 5-8 Separation 108 - HP 4550 | Service Manual - Page 111
a positive charge on the residual toner. When the residual toner reaches the drum, it is transferred to the drum's surface by the drum's negative charge. The residual toner is then transferred from the ITB to the drum. This waste toner is then removed from the drum's surface by a cleaning blade - HP 4550 | Service Manual - Page 112
the toner together to produce the full-color image on the page. This process uses upper and lower rollers made of Teflon tubing to reduce sticking. Both rollers are heated by Halogen heaters, which cause the four colors to fuse and mix on the paper, creating the permanent image. Figure 5-11 Fuser - HP 4550 | Service Manual - Page 113
is monitored and corrected during the following occurrences: when the power is activated after a certain number of sheets are printed when a toner cartridge is replaced when the drum cartridge is replaced when the printer wakes up after a standby mode of six hours or more Figure 5-12 - HP 4550 | Service Manual - Page 114
earlier in the image formation section, the residual toner from the ITB is transferred to the drum. A cleaning blade scrapes the residual toner off the drum's surface. The waste toner is then carried by toner feed plates into the waste toner reservoirs for storage. 112 Theory of operation C7085 - HP 4550 | Service Manual - Page 115
will be seen first. Only when printing full-color pages with a high percentage of coverage or when a lot of waste toner is removed from the ITB will the WASTE TONER FULL message be displayed before the DRUM LIFE OUT message. Intermediate transfer belt The entire print image forms on the intermediate - HP 4550 | Service Manual - Page 116
printer receives a print command, the ITB is lifted into position against the drum drum. Home position detection The home position of the ITB is detected to precisely transfer the four toners to the intermediate transfer For full-color printing, manually corrected. 114 Theory of operation C7085-90921 - HP 4550 | Service Manual - Page 117
Once the ITB counter gear has rotated one complete turn, the tabbed lever drops into the gear ITB with the secondary transfer roller at the time of secondary transfer. During "first page out," the secondary transfer roller engages with the belt prior to drum-to-belt image transfer to stabilize the - HP 4550 | Service Manual - Page 118
/ separation lever. This causes the lever to lift up on the ITB until it comes into contact with the photosensitive drum. The ITB will stay engaged with the drum throughout the transfer process. Once the entire print job is complete and CL3 and CL4 have been deactivated, the DC controller turns CL2 - HP 4550 | Service Manual - Page 119
Figure 5-19 ITB unit contact/separation unit C7085-90921 Chapter 5 Theory of operation 117 - HP 4550 | Service Manual - Page 120
carousel The toner carousel holds the printer's four toner cartridges: K (black), M (magenta), C (cyan), and Y (yellow). The carousel motor (M3) rotates the carousel, and the toner cartridge motor (M5) provides the drive for the positioning cam and the developer sleeve. The carousel contains three - HP 4550 | Service Manual - Page 121
developing sleeve. Once development is complete, M5 again rotates clockwise, moving the toner cartridge away from the drum. The toner cartridge contact sensor detects when the toner cartridge has moved away from the drum. The carousel motor (M3) again begins the carousel rotation, and the process - HP 4550 | Service Manual - Page 122
detection Note The Color LaserJet 4550 series has a continuous toner level sensor (CTLS) that was not available in the 4500 series. The continuous toner level sensing printed circuit assembly (PCA) is mounted on the right side of the printer. The sensor allows the printer to track toner usage and - HP 4550 | Service Manual - Page 123
Laser driver PCB Collimator lens Cylindrical lens Six-faced prism mirror Scanner driver BD PCB Photosensitive drum Figure 5-24 Laser/scanner operation Scanner motor Focusing lens BD mirror Reflective mirror C7085-90921 Chapter 5 Theory of operation 121 - HP 4550 | Service Manual - Page 124
the cassette pick-up roller and is then fed by the feed rollers. For manual feeding, a sheet of paper is picked up by the multi-purpose tray pick the leading edge of the image on the photosensitive drum. The paper then passes between the secondary transfer roller and the ITB. The paper continues past - HP 4550 | Service Manual - Page 125
is fed into the printer's paper path. The cassette feed roller and another feed roller feeds the paper into the printer. The paper passes CL1), which feeds the paper to the secondary transfer unit. The leading edge of the image on the intermediate transfer belt is matched with the leading edge of the - HP 4550 | Service Manual - Page 126
thus picked-up by its rotation. After the separation pad separates multiple sheets, the paper is fed into the printer one sheet at a time. Figure 5-27 Tray 1 manual feed Table 5-3 Motors, solenoids, clutches, and sensors Reference Description M2 Pick-up motor SL1 Multi-purpose tray pick-up - HP 4550 | Service Manual - Page 127
Last paper detected The printer detects the last page of the print job before writing the next image. This prevents toner particles from smearing on the photosensitive drum and ITB. To detect the last paper, the last paper sensor (PS3) monitors the rotation of the last paper detection roller on the - HP 4550 | Service Manual - Page 128
. The paper feeder is controlled by the DC controller. It does not contain a microcomputer (CPU) or a drive motor. Its rollers are controlled by the printer's pick-up motor (M2). Pick-up and feed system Three switches (SW3001, SW3002, and SW3003) on the paper feeder PCB detect the paper size and - HP 4550 | Service Manual - Page 129
unit is then detected by the delivery unit paper sensor (PS7). The pressure release sensor (PS6) detects when the fusing roller pressure is off. The printer uses a deflector to switch between the face-up bin and face-down bin. When the face-up bin is open, the paper is delivered to - HP 4550 | Service Manual - Page 130
, which is rotated by the reversing motor (M3102). The paper is then fed into the printer by the duplexing unit feed roller after the side registration roller is adjusted by the side registration guide (see Figure 5-32). Figure 5-32 Reversing and duplex pick-up operation 128 Theory of operation - HP 4550 | Service Manual - Page 131
) detects the trailing edge of the paper fed into the reversed unit, the duplex driver PCB changes the paper feed direction by rotating the reversing motor clockwise. Paper is then fed along the lower duplex guide until the paper reaches the duplex feed unit. Figure 5-33 Reversing operation C7085 - HP 4550 | Service Manual - Page 132
printer adjusts side registration so that the center of the paper (in the horizontal direction), matches the center of the printable area on the ITB when printing on the second side. The side registration guides guide, the duplex driver PCB stops M3103 and holds the side registration guide - HP 4550 | Service Manual - Page 133
After the side registration adjustment is completed, the duplex driver sends the refed paper presence status to the printer. Once the status is reviewed by the printer, it sends the duplex unit pick-up command to the duplex driver. The duplex driver activates the duplex feed motor (M3101) and feeds - HP 4550 | Service Manual - Page 134
the entire printing process. The DC controller enables the drive circuitry for the laser beam and coordinates print data from the formatter with paper size, laser beam motion, the high voltage system, fuser temperature, and motors. The DC controller also shares machine status information with the - HP 4550 | Service Manual - Page 135
the image formation assembly. The printer also contains three fans. Figure Pick-up motor M3 Carousel motor M4 Drum motor M5 Toner cartridge motor FM1 Large fan FM2 transfer roller, feed belt, feed roller, ITB contact clutch, ITB cleaning roller contact clutch, and the secondary transfer - HP 4550 | Service Manual - Page 136
operates the developer sleeve in the toner cartridge and performs the toner contact/separation function. Fan motor The fan motor is a DC brushless motor containing a hall element and the motor driver circuit. The printer has two exhaust fans (FM1 and FM2) and one inducting fan (FM3). 134 Theory of - HP 4550 | Service Manual - Page 137
sections of the printer. There is an AC/DC power supply and a high-voltage power supply. See Chapter 6 for instructions on accessing the door switch or the rear door switch is deactivated by opening the drum drawer, ITB drawer, toner access cover, or delivery door. These switches are in a series - HP 4550 | Service Manual - Page 138
back on again. High-voltage power supply The printer contains two high-voltage PCBs mounted in one assembly. Together, these PCBs generate the voltage supplied to the primary charging roller, developing sleeve, primary transfer roller, secondary transfer roller, ITB cleaning roller, and upper fusing - HP 4550 | Service Manual - Page 139
Interference (RFI) shield 156 Laser/scanner assembly 157 DC controller 158 Developing PCB 159 Top cover switch assembly 161 Drum drawer (top drawer) (CL3 189 ITB clutch (CL2) assembly 190 Transfer roller cam clutch (CL4 192 Left side gears 193 C7085-90921 Chapter 6 Removal and replacement - HP 4550 | Service Manual - Page 140
Rear assemblies 195 Large right side fan 195 Left side fan 197 Face-down assembly 199 Internal assemblies 200 Cartridge carousel assembly 200 Toner catch tray and paper transport assembly 204 Paper pick rollers 205 138 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 141
replace major printer components. (HP does not support repairing individual subassemblies or troubleshooting to the printer. HP recommends reinstalling the original cover whenever the drum is removed from the printer. Caution regarding electrostatic discharge (ESD) The printer contains parts - HP 4550 | Service Manual - Page 142
then you have an older version. The HP Color Laserjet 4550 printer is equivalent to the newer version of the HP Color LaserJet 4500 printer, unless otherwise specified. Required tools The following tools are needed to service the printer: Phillips #2 magnetized screwdriver (152-mm [6-inch] shaft - HP 4550 | Service Manual - Page 143
Always note where each type of screw is located and replace each one into its original location. Table 6-1 Types of screws Illustration Description Screw, machine w/washer Uses To hold plastic to metal. example: printer skins Screw, self tapping To hold plastic to plastic. Screw, trus head - HP 4550 | Service Manual - Page 144
black and white only pages, or 12.5 months for color pages See page 89. TRANSFER KIT OUT REPLACE KIT Fuser kit 4500: FUSER KIT LOW or FUSER KIT OUT REPLACE KIT 4550: FUSER KIT LOW ORDER FUSER KIT 100,000 black and white only pages, or 50,000 color pages 50 months for black and white only pages - HP 4550 | Service Manual - Page 145
CAUTION Hewlett-Packard recommends the use of HP products in this printer. Use of non-HP products can cause problems that require service that is not covered by the Hewlett-Packard warranty or service agreements. C7085-90921 Chapter 6 Removal and replacement 143 - HP 4550 | Service Manual - Page 146
from light. Exposure to light for more than 15 seconds can seriously damage the imaging drum. 2 Push the release button on the left side of the printer and open the top cover. 3 Open the rear door(s) of the printer. 4 Remove the air filter. 5 Remove the two screws from the top cover as shown - HP 4550 | Service Manual - Page 147
it from light. 2 Remove the top cover. Exposure to light for more than 15 seconds can seriously damage the imaging drum. 3 Open the ITB drawer (middle drawer) and Tray 2. 4 Remove the two screws as shown in callout 1 of figure 6-3. 5 Carefully pull out the bottom of the - HP 4550 | Service Manual - Page 148
cover To remove the right side cover from the printer 1 Open the drum drawer (top drawer) and remove the imaging drum, protecting it from light. 2 Remove the top cover. Exposure to light for more than 15 seconds can seriously damage the imaging drum. 3 Open the ITB drawer (middle drawer) and Tray - HP 4550 | Service Manual - Page 149
inside of the rear door as shown in Figure 6-5. 3 Slide the bottom of the rear door to your right until the plastic guide-pin clears the guide-pin harness attached to the printer. 4 Remove the rear door. Figure 6-5 Rear door removal and replacement C7085-90921 Chapter 6 Removal and replacement 147 - HP 4550 | Service Manual - Page 150
cover. 2 Remove the right side cover. 3 Remove the screw as shown in Figure 6-6. 4 Rotate the top of the cover toward the left side of the printer and remove the cover. Reinstallation tip Ensure that the lip on the lower right side of the cover slides behind the lower rear cover. Figure - HP 4550 | Service Manual - Page 151
of the HP Color LaserJet 4500 series printers are available. To identify which printer version you are servicing, see page 140. The HP Color LaserJet 4550 printer is equivalent to the newer version of the HP Color LaserJet 4500 printer, unless otherwise specified. 1 Open the drum drawer (top - HP 4550 | Service Manual - Page 152
tabs into the black plastic levers (Figure 6-8). In newer version HP Color LaserJet 4500 and HP Color LaserJet 4550 printer, insert the metal tabs (located just inside the black plastic tabs shown in Figure 6-8) into the drum drawer (top drawer) cover before latching the cover onto the bottom - HP 4550 | Service Manual - Page 153
ITB drawer (middle drawer) cover To remove the ITB drawer (middle drawer) cover 1 Open the ITB drawer (middle drawer) until it stops. 2 Remove the two screws in the top of the ITB drawer (middle drawer) cover as shown in Figure 6-9. 3 Lift up on the cover slightly. Tilt the top toward you and then - HP 4550 | Service Manual - Page 154
ITB drawer (middle drawer) completely out until it stops. 2 Remove the intermediate transfer belt (ITB). 3 Lift the drawer, clearing the first set of guide wheels from the guide rail (Figure 6-10). Pull the guide rails until the next set of guide wheels stop, and then lift to clear the second set of - HP 4550 | Service Manual - Page 155
shown in Figure 6-11. 4 Pull the bottom of the control panel out to clear the alignment pin. 5 Lift the control panel up to access the cable. 6 Disconnect the cable. Figure 6-11 Control panel removal and replacement C7085-90921 Chapter 6 Removal and replacement 153 - HP 4550 | Service Manual - Page 156
came in the printer box and remove it from the bag. If you are installing an overlay, rather than replacing one, skip to step printer. 3 Grasp the bottom of the overlay, pull it down, and then lift it out. When removing the control panel overlay, you might want to use a small flat-blade screw driver - HP 4550 | Service Manual - Page 157
protecting it from light. Exposure to light for more than 15 seconds can seriously damage the imaging drum. 3 Open the ITB drawer (middle drawer). 4 Remove the control panel. 5 Remove the three screws as shown in callout 1, Figure 6-12. 6 Using a small flat-blade screwdriver, - HP 4550 | Service Manual - Page 158
Note Radio Frequency Interference (RFI) shield To remove the RFI shield Turn the printer off, wait five seconds, and then unplug the printer. 1 Remove the top cover. 2 Remove the left side cover. 3 Remove the 13 screws shown in Figure 6-13. 4 Lift up on the RFI shield and remove. - HP 4550 | Service Manual - Page 159
/scanner assembly To remove the laser/scanner assembly Turn the printer off, wait five seconds, and then unplug the printer. 1 Remove the top cover. 2 Remove the left side cover. 3 Remove the RFI shield. 4 Disconnect the cable from the laser/scanner to the DC controller (J1006 on the DC controller - HP 4550 | Service Manual - Page 160
To remove the DC controller Turn the printer off, wait five seconds, and then unplug the printer. 1 Remove the top cover. 2 Remove the left side cover. 3 Remove the RFI shield. 4 Disconnect all connectors from the DC controller, including the two ribbon cables. 5 Remove the five screws from the DC - HP 4550 | Service Manual - Page 161
stay (callout 2, Figure 6-17 on page 160). 7 Remove the five or four screws (depending on the version of printer that is being serviced) from the developing PCB (callout 1, Figure 6-17 on page 160). 8 Lift the developing PCB up and out. Reinstallation tip When securing the developing PCB with - HP 4550 | Service Manual - Page 162
1 2 Figure 6-17 Developing PCB removal and replacement (2 of 2) 160 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 163
HP Color LaserJet 4500 serial numbers xxH or higher and HP Color LaserJet 4550 printers: 1 Open the drum drawer (top drawer) until it stops and remove the imaging drum, protecting it from light. Exposure to light for more than 15 seconds can seriously damage the imaging drum. 2 Free the cables - HP 4550 | Service Manual - Page 164
1 3 2 Figure 6-18 Top cover switch assembly removal and replacement 1 Figure 6-19 Top cover switch assembly removal and replacement 162 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 165
(top drawer) switch (see callout 1, Figure 6-20). 1 Figure 6-20 Drum drawer (top drawer) switch 8 Free the main cable from all cable stays at the top and left side of the printer; push the cables back toward the rear of the printer. 9 Remove the two screws from the black plastic housing shown in - HP 4550 | Service Manual - Page 166
clips in place (see Figure 6-22 and Figure 6-23). 12 Pull the drum drawer (top drawer) straight out and away from the printer. Reinstallation tip When replacing the drum drawer (top drawer) assembly, make sure the cable is lying flat in the cable guide. 164 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 167
Figure 6-22 Drum drawer (top drawer) assembly removal and replacement (2 of 3) The following graphic shows an alternative method of removing the left side of the drum drawer. Figure 6-23 Drum drawer assembly removal and replacement (3 of 3) C7085-90921 Chapter 6 Removal and replacement 165 - HP 4550 | Service Manual - Page 168
the printer off, wait five seconds, and then unplug the printer. 1 Open the drum drawer (top drawer) until it stops and remove the imaging drum, (1 of 2) 4 Remove the plastic cable cover as shown in Figure 6-25. 5 Remove the cable from the cable stays, and then disconnect the connector from - HP 4550 | Service Manual - Page 169
Figure 6-25 Densitometer removal and replacement (2 of 2) C7085-90921 Chapter 6 Removal and replacement 167 - HP 4550 | Service Manual - Page 170
the formatter out of the rear of the printer. Figure 6-26 Formatter removal and replacement Note The HP Color LaserJet 4550 printer formatter looks different externally, but the removal procedure is the same as for the HP Color LaserJet 4500 printer. 168 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 171
the old formatter PCB and install them on the new formatter PCB, making sure the firmware DIMM is installed in the ROM ONLY DIMM slot of the HP Color LaserJet 4500 printer, or Slot #3 (J7) of the HP Color LaserJet 4550 printer. 8 Install the EIO cards (if any). 9 Install the formatter back into the - HP 4550 | Service Manual - Page 172
Note CAUTION Formatter pan assembly To remove the formatter pan assembly Turn the printer off, wait five seconds, and then unplug the printer. 1 Open the drum drawer (top drawer) until it stops and remove the imaging drum, protecting it from light. Exposure to light for more than 15 seconds can - HP 4550 | Service Manual - Page 173
(3 of 4) Note Although Figure 6-29 depicts the RFI shield still installed, make sure this shield was removed at step 7. 13 Remove the control panel cable from its cable stay, if necessary. 14 Remove the screws from the formatter pan assembly (shown in Figure 6-29 and Figure 6-30). 15 To remove the - HP 4550 | Service Manual - Page 174
of 4) Reinstallation tip Be sure the four tabs (two on the top and one each on the rear and front of the formatter pan assembly) are engaged prior to tightening the screws. Be sure to reconnect the ribbon cable from the DC controller shown in callout 1, Figure 6-29. 172 Removal and replacement - HP 4550 | Service Manual - Page 175
HP Color LaserJet 4500 series printers are available; the later version is equivalent to the HP Color LaserJet 4550 unless otherwise noted. To identify which printer version you are servicing, see page 140. 1 Remove the formatter pan assembly. 2 Disconnect the four connectors (three in front and one - HP 4550 | Service Manual - Page 176
, wait five seconds, and then unplug the printer. Two versions of the HP Color LaserJet 4500 series printers are available; the newer version is equivalent to the HP Color LaserJet 4550 unless otherwise noted. To identify which printer version you are servicing, see page 140. 1 Remove the formatter - HP 4550 | Service Manual - Page 177
1 Figure 6-33 High-voltage power supply removal and replacement (older version HP Color LaserJet 4500 printers) C7085-90921 Chapter 6 Removal and replacement 175 - HP 4550 | Service Manual - Page 178
v-shaped clip underneath the DC controller to loosen the cable guide. Slide the trough toward the rear of the printer until it is free. 7 Disconnect J204 on the developing PCB and free it from its cable stay. 8 Remove the eight black screws from the drum drive assembly shown in Figures 6-35 and 6-36 - HP 4550 | Service Manual - Page 179
Figure 6-35 Drum drive assembly removal and replacement (2 of 3) Figure 6-36 Drum drive assembly removal and replacement (3 of 3) C7085-90921 Chapter 6 Removal and replacement 177 - HP 4550 | Service Manual - Page 180
To remove the large fan housing Turn the printer off, wait five seconds, and then unplug the printer. 1 Remove the formatter pan assembly. 2 connector J209 on the developing PCB and free the cable from its cable stays. 5 Unweave the cable from the cable trough to remove it. 6 Remove the screw from - HP 4550 | Service Manual - Page 181
the printer. 1 Remove the formatter pan assembly. 2 Remove the rear door. 3 Remove the large fan housing and the fan. 4 Remove the toner level sensing assembly from the HP Color LaserJet 4550 (see Figure 6-39). Figure 6-39 Toner level sensor assembly removal and replacement 5 Free the cables from - HP 4550 | Service Manual - Page 182
drive assembly. 11 Carefully remove the carousel drive assembly by pulling the assembly straight out. CAUTION Be sure to reconnect the sensor cables (see Figure 6-40, callout 2) Carousel drive assembly replacement tip When replacing the carousel drive assembly, be sure to align the "D" shaped - HP 4550 | Service Manual - Page 183
Note Paper size switch PCB To remove the paper size switch PCB Turn the printer off, wait five seconds, and then unplug the printer. 1 Pull Tray 2 out. 2 Remove the high-voltage power supply. 3 Disconnect the connector as shown in callout 1. 4 Remove the black screw from the paper size switch - HP 4550 | Service Manual - Page 184
Left side assemblies Drawer switch assembly To remove the drawer switch assembly 1 Remove the top cover. 2 Remove the left side cover. 3 Disconnect the connector shown in callout 1. 4 Remove the two screws from the drawer switch assembly shown in callout 2. 5 Pull the drawer switch assembly away - HP 4550 | Service Manual - Page 185
Note Paper feed PCB To remove the paper feed PCB Turn the printer off, wait five seconds, and then unplug the printer. 1 Remove the top cover. 2 Remove the left side cover. 3 Remove the rear door. 4 Remove the fusing assembly. 5 Disconnect the small fan connector shown in callout 1. 2 1 2 3 - HP 4550 | Service Manual - Page 186
7 Remove the screw in the black plastic cover shown in callout 3, Figure 6-44. 8 Remove the black plastic cover. 9 Remove the eight cables from their connectors on the paper feed PCB shown in Figure 6-46. 10 Remove the screw from the rear of the paper feed PCB (callout 4, - HP 4550 | Service Manual - Page 187
motor (M1) To remove the fusing motor Turn the printer off, wait five seconds, and then unplug the printer. 1 Remove the top cover. 2 Remove the left Remove the screw that secures the white cable trough to the chassis (callout 2). 3 1 2 Figure 6-47 Fuser motor removal and replacement (1 of 2) - HP 4550 | Service Manual - Page 188
, as shown in callout 3, and then remove the cover. 9 Remove the three fuser motor screws shown in Figure 6-48. 10 Carefully pull to remove the fuser motor and free the cable from the cable trough. Figure 6-48 Fuser motor removal and replacement (2 of 2) 186 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 189
Paper path pick-up motor (M2) Turn the printer off, wait five seconds, and then unplug the printer. 1 Remove the top cover. 2 Remove the left side cover. 3 Disconnect the paper path motor connector (J109) from the paper feed PCB and remove it from the cable trough. 4 Remove the two screws on both - HP 4550 | Service Manual - Page 190
cable stays. Note the cable path when removing the cable. 4 Remove the screw (callout 1) and e-clip (callout 2) that hold the solenoid assembly in place, and then remove the solenoid assembly. For HP Color LaserJet 4500 printers with serial numbers xxH or higher and HP Color LaserJet 4550 printers - HP 4550 | Service Manual - Page 191
CAUTION Make sure that the clutch assembly gears are correctly reinstalled. For older printers, the gear alignment marks should be offset by one gear tooth as shown in Figure 6-51; for newer printers, the gears, which have a double line, should be aligned. C7085-90921 Chapter 6 Removal - HP 4550 | Service Manual - Page 192
the screw shown in Figure 6-52 and remove the plastic shroud. Figure 6-52 ITB clutch assembly removal and replacement (1 of 2) 5 Disconnect the cable from the clutch assembly. 6 Remove the three screws shown in Figure 6-53 and remove the clutch assembly. Figure 6-53 ITB clutch assembly removal - HP 4550 | Service Manual - Page 193
CAUTION Make sure that the clutch assembly gears are correctly reinstalled. For older printers, the gear alignment marks should be offset by one gear tooth as shown in Figure 6-51; for newer printers, the gears, which have a double line, should be aligned. For proper operation, ensure that the ITB - HP 4550 | Service Manual - Page 194
. 4 Remove the e-clip shown in Figure 6-54 with needle-nose pliers and remove the clutch. Figure 6-54 Transfer roller cam clutch removal and replacement Replacement tip For proper operation, ensure that the cable is connected to J105 on the paper feed PCB. 192 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 195
PCB and free the cables from the cable stays. 6 Remove fuser motor. 8 Remove the paper path motor. 9 Remove the three clutches: CL2, CL3, and CL4. 10 Remove the four screws (callout 1, Figure 6-55 on page 194) and remove the sheet metal over the gears. 11 Remove the one flat parts of the pickup - HP 4550 | Service Manual - Page 196
3 1 2 Figure 6-55 Left side gears removal and replacement (1 of 2) 2 1 Figure 6-56 Left side gears removal and replacement (2 of 2) 194 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 197
at the top and bottom of the fan housing, and then slide the fan out. Large right side fan replacement tip Ensure that the fan cable is facing out and located in the lower corner. Figure 6-57 Large right side fan removal and replacement (1 of 2) C7085-90921 Chapter 6 Removal and replacement - HP 4550 | Service Manual - Page 198
Figure 6-58 Large right side fan removal and replacement (2 of 2) 196 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 199
6-59 and 6-60 (callout 2) and remove the fan shield. 6 Disconnect the cable shown in callout 1, Figure 6-61. 7 Remove the screw from the black plastic the fan casing shown in callout 2, Figure 6-61. 8 Free the fan cable from the cable stay. 9 Press out on the three plastic tabs and slide the fan - HP 4550 | Service Manual - Page 200
2 Figure 6-60 Left side fan removal and replacement (2 of 3) 2 1 Figure 6-61 Left side fan removal and replacement (3 of 3) 198 Removal and replacement C7085-90921 - HP 4550 | Service Manual - Page 201
cover. 3 Remove the rear door. 4 Remove the left side fan. 5 Disconnect the bin full sensor shown in callout 1, Figure 6-62, and free the cable from the cable stay. 6 Remove the three screws from the face-down assembly shown in callouts 2 and 3, Figure 6-62. 7 With your right hand, lift up slightly - HP 4550 | Service Manual - Page 202
the cartridge carousel assembly 1 Remove the intermediate transfer belt and imaging drum cartridge. Protect the drum cartridge from light. Exposure to light for more than 15 seconds can seriously damage the imaging drum. 2 Remove the developers (toner cartridges) from the carousel and store them in - HP 4550 | Service Manual - Page 203
Figure 6-64 Cartridge carousel replacement - continuous toner level sensor assembly (2 of 6) 17 Remove the laser shutter cover by pushing down on the silver tab in the middle and then rotating the shutter toward the rear of the printer (see - HP 4550 | Service Manual - Page 204
callout 3) on the printer's right side. 24 Disconnect the cables going to PS-11 and the Continuous Toner Level Sensor (CTLS drum bushing assembly (see Figure 6-66, callout 5). 27 Remove the left-side carousel mounting plate. 28 Remove all visible screws from the carousel mounting plate on the printer - HP 4550 | Service Manual - Page 205
29 Standing at the rear of the printer, lift the left side of the carousel while applying pressure toward you to the rear cross-member plate. As soon as the carousel clears the - HP 4550 | Service Manual - Page 206
the paper transport assembly 1 Remove the fusing assembly. 2 Remove the toner catch tray by pushing down on the clip in the middle and the assembly out of the printer. Paper transport assembly replacement tip Verify that all tabs are under the metal slots (two on the right, one on the left) and that - HP 4550 | Service Manual - Page 207
printer you are working with, and follow the instructions provided below, for the appropriate version of the printer. For 4500 series printer For 4500 series printer serial numbers xxH or higher and 4550 parts of the D-shaped rollers are facing up. Grasping the center of the D-shaped roller with one - HP 4550 | Service Manual - Page 208
Star wheel assembly To remove the star wheel assembly: 1 Remove the ITB drawer. 2 Open the drum drawer and remove the drum cartridge. 3 Disconnect the spring as shown in (callout 1). 4 Remove the linkage screw on the left (callout 2). 5 Carefully pull the assembly forward to remove it from - HP 4550 | Service Manual - Page 209
roller assembly To remove the transfer roller assembly 1 Remove the HVPS. 2 Remove the left side cover. 3 Remove the ITB drawer. 4 Open the drum drawer and remove the drum cartridge. 5 Remove the star wheel assembly. 6 Using needle-nose pliers, remove the E-ring on each side of the shaft. 7 Remove - HP 4550 | Service Manual - Page 210
Note Cam shafts To remove the cam shafts 1 Remove the HVPS. 2 Remove the left side cover. 3 Remove the ITB drawer. 4 Open the drum drawer and remove the drum cartridge. 5 Remove the appropriate clutch or gear on the left side. 6 Using needle-nose pliers, remove the e-rings from each end of the - HP 4550 | Service Manual - Page 211
checklist 241 Jam recovery 242 Image formation troubleshooting 243 Print density test and color checks 243 Understanding color variations 244 Color selection process 244 Customizing color output through printer drivers 244 Adjusting color balance 250 Image defects 253 Overhead transparency - HP 4550 | Service Manual - Page 212
Troubleshooting tools 285 Embedded Web server 285 Printer configuration page 287 Event log 292 Hard disk file directory page 292 Service mode 293 Accessing the service mode 293 Serial number 296 Transfer maintenance count 296 Fuser maintenance count 296 Color page count 296 Total page - HP 4550 | Service Manual - Page 213
for entering service mode and performing service-oriented tasks. These tasks include counts for entering the serial number, transfer maintenance, fuser maintenance, color page, total page, clearing the event log, and various printer tests. The diagnostics mode section provides instructions on how - HP 4550 | Service Manual - Page 214
the root cause of hardware malfunctions. The flowchart guides you to the appropriate section of this chapter that provides steps for correcting the malfunction. Check the printer for the following before troubleshooting a specific printer problem: Has regular maintenance been performed? Are the - HP 4550 | Service Manual - Page 215
)? If so, wipe affected parts dry or leave the printer on for 10 to 20 minutes. Miscellaneous Check for and remove any non-HP components (toner, memory modules, and EIO cards) from the printer. If hardware or software configuration has not changed, or the problem is not associated with any - HP 4550 | Service Manual - Page 216
Figure 7-1 Troubleshooting flowchart (1 of 2) 214 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 217
Troubleshooting flowchart (continued) Figure 7-2 Troubleshooting flowchart (2 of 2) C7085-90921 Chapter 7 Troubleshooting 215 - HP 4550 | Service Manual - Page 218
. If the front panel display looks dark and an error message appears, check the ribbon cable between the formatter and the DC controller. 5 Remove any HP JetDirect or other EIO cards, then retry powering-on the printer. 6 Make sure the control panel display is on. 7 Check fuse in power supply (see - HP 4550 | Service Manual - Page 219
color calibration. This process should take approximately 90 seconds. Action: No action required. CANCELING JOB Description: Action: The printer is canceling the current print job. Incoming data No action required. for the current job will be discarded. C7085-90921 Chapter 7 Troubleshooting - HP 4550 | Service Manual - Page 220
: Action: The drawer that holds the intermediate transfer belt is open. 1. This drawer is called printer and closes SW5. Close the upper rear drawer. If the message persists, remove the printer's left-side cover and inspect the mechanical linkage of SW5 and the lever. 218 Troubleshooting - HP 4550 | Service Manual - Page 221
or not the printer's toner access cover is closed. When the toner access cover is closed drum or ITB drawer is open. COLD RESET (4500) -or- RESTORE FACTORY SETTINGS (4550) Description: The cold reset power-up sequence has been entered. CONTINUOUS PAGE PRESS CANCEL JOB (4500) Action: Most printer - HP 4550 | Service Manual - Page 222
of the printer Replace the drum kit. drum kit. DRUM LIFE LOW REPLACE DRUM KIT (4500) -or- DRUM LIFE LOW ORDER DRUM KIT (4550) Description: Approximately 80% of the drum's life has been consumed. DRUM LIFE OUT REPLACE DRUM KIT Action: Continue printing and order the drum kit. Drum replacement - HP 4550 | Service Manual - Page 223
7-2 Alphabetical printer error messages (continued) FUSER LIFE LOW REPLACE KIT (4500) -or- FUSER LIFE LOW ORDER KIT (4550) Description: Approximately 95% of the fuser's life has been consumed. Fuser Life Out Replace Kit Action: Continue printing, or replace the fuser kit. Fuser replacement will - HP 4550 | Service Manual - Page 224
in toner cartridge replacement mode. toner replacement mode. PRINTER LANGUAGE NOT AVAILABLE Description: The printer received a request for a new language (personality) that does not exist in the printer. PRINTING CALIBRATION PAGE Action: No action required. Description: The color calibration - HP 4550 | Service Manual - Page 225
state upon completion of this page. PRINTING LASERJET DEMO (4500) -orPRINTING DEMONSTRATION (4550) Description: The demo page is being printed. The printer returns to the READY state upon completion of this page. PRINTING LASERJET DEMO 2 (4500 only) Action: No action required. Description: The - HP 4550 | Service Manual - Page 226
Press [Go] to end Service Mode. entered. The printer will remain in Service Mode until [Go] is pressed. TONER CMYK LOW Description: Action: The toner cartridge specified is low on toner. This message Printing will continue until a TONER OUT message appears. appears if TONER=LOW (default) is - HP 4550 | Service Manual - Page 227
printer error messages (continued) TONER POSITION [COLOR] = [STATE] Description: Indicates the current state of a particular toner cartridge. This message appears when [Select] is pressed while a TONER LOW/OUT message appears. TRANSFER KIT LOW REPLACE KIT (4500) -or- TRANSFER KIT LOW ORDER KIT - HP 4550 | Service Manual - Page 228
and light pipes are not blocked. Numerical printer error messages Table 7-3 Numerical printer error messages 13.XX Jam Note Refer to the jam troubleshooting section for the complete details about locating jams (see page 237). XX Description: 4500 4550 0 1 Jam in input feed area 1 5 Jam in - HP 4550 | Service Manual - Page 229
in the front part of the printer immediately after it might be located in the fuser area or between the transfer area and the 2. fuser. Open the ITB drawer and printer's internal memory is printed. 2. To cancel the job, press [Cancel Job]. 3. Add more memory to resolve the problem Troubleshooting 227 - HP 4550 | Service Manual - Page 230
Table 7-3 Numerical printer error messages (continued) 40 EIO X DATA ERROR alternates with PRESS GO TO CONTINUE (4500) -or- 40 EIO BAD TRANSMISSION (4550) Description: A connection with the card in the specified slot has been broken. Action: 1. Check that all cables are connected to the EIO ports - HP 4550 | Service Manual - Page 231
Table 7-3 Numerical printer error messages (continued) Troubleshooting 49 errors C7085-90921 Chapter 7 Troubleshooting 229 - HP 4550 | Service Manual - Page 232
decompressed.) Use the following series of commands to put the printer into Lossy mode: ESC%-12345X@PJL @PJL Default Service mode=HPBOISEID @PJL Default Diagnostics=ON @PJL Enter Language = PCL ESC%-12345X@PJL Esc*z9999P Esc*z50P Esc*z201X (Continued on next page) 230 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 233
warms up. X Description: 1 Low temperature error 2 Fuser warm-up service 3 High fuser temperature 4 Faulty fuser 5 Fuser voltage mismatch (verify that you have NOT installed a 110V fuser in a 220V printer or vice-versa). 6 Fuser heater cutoff 7 Fuser motor malfunction (see recommended action for 50 - HP 4550 | Service Manual - Page 234
PCB is firmly seated (this connector contains the wiring for PS6, which provides fuser-motion feedback). 51 LASER ERROR (4500) -or- 51.X PRINTER ERROR (4550) Description: Indicates a beam detect error or laser failure. Note Closely inspect the mechanical linkage. The gears along the gear "drive - HP 4550 | Service Manual - Page 235
width tabs (four tabs, one for each cartridge) on the left-end of the Action: 1. Turn the printer off and then on to reset the printer. 2. Open the color toner door and look for an obstruction. If necessary, remove the toner cartridges individually by manually releasing the carousel brake and - HP 4550 | Service Manual - Page 236
printer side with a dry cloth. 4. Check the light guide and clean it if necessary. Replace the light guide if the ends are scarred. 5. Reconnect the waste toner sensor unit connector and the DC controller PCB connector (J1009) correctly. 6. Replace the waste toner sensor (PS13). 234 Troubleshooting - HP 4550 | Service Manual - Page 237
printer off and on to reset the printer color plane alignment procedures. 57.1 FAN FAILURE Description: The printer printer off and on to reset the printer printer's printer off and on to reset the printer printer's drum drawer (refer to Figure 7-32). (The drum printer off and on to reset the printer - HP 4550 | Service Manual - Page 238
one. Turn the printer off and on to reset the printer. Reseat the firmware DIMM, making sure it is in the slot surrounded by a white line with the text "ROM ONLY IN THIS SLOT." 62.X PRINTER ERROR Description: Indicates that a problem SERVICE (XXXX) PRINTER ERROR Action: 1. Check printer settings - HP 4550 | Service Manual - Page 239
Paper path troubleshooting Jams Jam error messages appear if paper fails to arrive at or clear the paper path sensors in the Duplex paper-pick sensor (PS3104) 3 Duplex pick-up sensor (PS3103) 4 Reversed paper sensor (PS3101) 5 Delivery paper sensor (PS7) C7085-90921 Chapter 7 Troubleshooting 237 - HP 4550 | Service Manual - Page 240
Use Figure 7-4 to troubleshoot jams in the printer. For instructions on clearing jams, see the sections later in this chapter. 8 1 7 2 3 6 4 5 Figure 7-4 Jam locations (shown with the optional 500-sheet paper feeder and duplex unit installed) 1 Tray 1 input area 2 Transfer belt area 3 Tray - HP 4550 | Service Manual - Page 241
instructions on clearing jams, see the sections later in this chapter. 10 11 9 8 7 12 6 5 13 14 4 Figure 7-5 3 2 1 Jam locations by error message See the next page for the Color LaserJet 4550 associated error messages. Table 7-4 HP Color LaserJet 4500 toner or paper dust on the fuser - HP 4550 | Service Manual - Page 242
Table 7-5 HP Color LaserJet 4550 jam locations and associated error Check the entire paper path. drawer. Check and pull out the Loose toner or paper dust on the fuser. density sensor can cause this error. Clean the sensor. 5 13.13 Check front duplex drawer. 240 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 243
. The HP LaserJet Printer Family Print Media Guide contains detailed information about media specifications (see page 325 for ordering information). Refer to the following list for common mediarelated printing problems. Rough paper causes poor toner transfer and smeared print problems. Check - HP 4550 | Service Manual - Page 244
Printer will attempt to reprint jammed pages. OFF Printer will not attempt to reprint jammed pages. During the recovery process, the printer . 4 Press [SELECT] to save the setting. 5 Press [GO] to return the printer to the READY state. To improve print speed, you might want to disable jam recovery. - HP 4550 | Service Manual - Page 245
toner cartridges intermediate transfer belt (ITB) unit secondary transfer roller Figure 7-6 Image formation Before beginning image formation troubleshooting, check that the media meets the specifications listed in the HP LaserJet Printer Family Print Media Guide. Print density test and color - HP 4550 | Service Manual - Page 246
's operating system. For specific instructions about using printer drivers, see the printer driver's Readme file, which is included on the printing system CD-ROM. The following color control features are available only through your HP printer driver. See the printer driver's online Help for details - HP 4550 | Service Manual - Page 247
-filled print areas. It also enhances photos by smoothing out fine color gradations. The Detail option is useful for text and graphics that require sharp distinctions among lines or colors, such as images that contain a pattern or a high level of detail. C7085-90921 Chapter 7 Troubleshooting 245 - HP 4550 | Service Manual - Page 248
and operating systems that support color management systems. For more information, see your printer driver online Help. Automatic is the default setting and is recommended for printing all color documents. Manual color adjustment The Manual color adjustment feature of HP ColorSmart II allows you - HP 4550 | Service Manual - Page 249
to your printer is to print sRGB colors. The HP Color LaserJet 4550 uses HP ColorSmart II, which uses sRGB and automatically optimizes color output. Keep in mind the above factors when colors on your screen do not perfectly match your printed colors. C7085-90921 Chapter 7 Troubleshooting 247 - HP 4550 | Service Manual - Page 250
CMYK colors through the PostScript printer driver. By default, the HP Color LaserJet 4550 series printer interprets CMYK data according to the Standard Web Offset Press (SWOP) standard. This standard defines how a particular set of CMYK inks should behave. The printer performs a SWOP color map - HP 4550 | Service Manual - Page 251
://www.hp.com/support/lj4550. Once connected, select Downloads and Drivers. Printer drivers, ICC color profiles, and sRGB color swatches Adobe Acrobat Vector graphics such as company logos created in one of the above applications (using palettes or applications that preserve 7 Troubleshooting 249 - HP 4550 | Service Manual - Page 252
the PANTONE® Matching System. These colors were created using sixteen inks on a lithographic printing press. Not all of these colors can be reproduced by a laser color printer because they are out of a laser printer's four-color range. PANTONE® calibrates HP printers to provide the closest match for - HP 4550 | Service Manual - Page 253
page Step 2: Adjust the cyan (C) density setting. Examine the cyan density bar (C) on the color balance calibration page from a distance of 2 meters (6 ft). If the center oval matches the to adjust the density: 1 Press [ITEM] until YELLOW DENSITY appears. C7085-90921 Chapter 7 Troubleshooting 251 - HP 4550 | Service Manual - Page 254
yellow (Y) numbers associated with this circle indicate the optimum gray balance settings for these colors. 2 Adjust the magenta and yellow settings (yellow is horizontal and magenta is vertical) yellow settings, press [GO] to return the printer to the READY state. 252 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 255
vertical directions of print quality problems refer to problems found on A-4 and faded print toner 2 (see page 259) (see page 259) Light black or no black print Loose toner (see page image available Single color missing (see page 260) No image available Sunburn (see page 260) Toner smear (see - HP 4550 | Service Manual - Page 256
the imaging drum and the developer can vary slightly. This can cause toner to be transferred unevenly and appear lighter or darker approximately every 38 mm (1.5 inches). This defect is more apparent in secondary colors. There is no workaround for this defect. 254 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 257
sync. The two white gears on the left side of the printer (see Figure 6-47) should have two timing marks pointing toward each other. • Cams with a single line should be off one tooth clockwise on the right gear. • Cams with a double line should be aligned. C7085-90921 Chapter 7 Troubleshooting 255 - HP 4550 | Service Manual - Page 258
toner cartridge. • Check the laser scanner shutter door for proper operation. The toner cartridge guide is damaged, improperly positioned, or missing. There is no transfer toner is not attracted to the drum. There is no drum ground path. • Check the drum ground. The laser scanner cable - HP 4550 | Service Manual - Page 259
The paper does not meet HP paper specifications or is stored improperly. The printer's operating environment does not meet HP specifications. The connection of the cables to the laser scanner is poor. The connection of the cables to the ECU is poor. The laser scanner is defective. The DC - HP 4550 | Service Manual - Page 260
The toner cartridge is defective. There is excess toner inside the printer. Clean the printer. The printer is printing on envelope seams. Move the text to an area away from seams. The imaging drum is defective or at the end of its life. Replace the drum kit. 258 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 261
the fuser kit. If one toner color is streaking, that toner cartridge has been damaged. Replace the toner cartridge for the streaking color. The paper does not meet HP paper specifications. Use media that meets HP media specifications. Light, dark, or faded print The message TRANSFER KIT LOW - HP 4550 | Service Manual - Page 262
image available CAUTION Loose toner Loose toner is in the printer. The toner cartridge is defective. The paper is too smooth. The driver setting for the paper type is wrong. The fuser is defective. Mottled or marbled output Print a configuration page, and refer to the color blocks at the - HP 4550 | Service Manual - Page 263
check the sleeve surface to confirm the defect, then replace the defective toner cartridge. There is a lack of toner or the toner cartridge is faulty. There is dirt in the laser path. The fuser is defective. A mirror in the laser scanner is dirty. C7085-90921 Chapter 7 Troubleshooting 261 - HP 4550 | Service Manual - Page 264
Wavy characters Mechanical instability in the scanner mechanism or the optics can cause wavy characters. Reprint the job to ensure that the problem persists. If the failure remains, replace the laser scanner assembly. 262 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 265
meet the specifications listed in the HP LaserJet Family Print Media Guide. If the transparencies have spots printer (part number C2934A for Letter, and C2936A for A4). The selected colors are undesirable when printed. Select different colors in your software application or printer driver - HP 4550 | Service Manual - Page 266
closing the large door at the rear of the printer, or by pulling a drawer open, and then quickly closing it. 4 While the printer is calibrating, the fuser rollers are rolling. Place the wipe up against each roller in turn, keeping it in place for five to 10 seconds. 264 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 267
Repetitive defects troubleshooting CAUTION Repetitive defects are defects that occur on the page. Most repetitive defects are caused by problems with one of the following: Table 7-8. Developer roller Charge roller Cleaning roller Transfer roller Fuser Imaging drum Transfer belt - HP 4550 | Service Manual - Page 268
of print defect Color developer 30 mm (1.2 in) Black developer roller 37 mm (1.5 in) Charge roller 40 mm (1.6 in) ITB cleaning roller 40 mm (1.6 in) Transfer roller 53 mm (2.1 in) Fuser 131 mm (5.2 in) Imaging drum 152 mm (6 in) Figure 7-8 Repetitive defect ruler 266 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 269
developer Color developer Fuser ITB ICL roller Transfer roller Distance 40 mm (1.6 in) 152 mm (6 in) 37 mm (1.5 in) 30 mm (1.2 in) 131 mm (5.2 in) 40 mm (1.6 in) 53 mm (2.1 in) Figure 7-9 Imaging drum exposed to light (proportions not to scale) C7085-90921 Chapter 7 Troubleshooting 267 - HP 4550 | Service Manual - Page 270
source of the problem. HP LaserJet printers are not designed to work with mechanical switch-box products without proper surge protection. These devices generate high transient voltages that cause permanent damage to the formatter PCB. This circumstance is not covered by the Hewlett-Packard warranty - HP 4550 | Service Manual - Page 271
manual is available with the HP PCL/PJL Reference Set on CD-ROM, part number 5021-0337. @PJL [Enter] This command enables the specified printer language. If the printer does not receive this command it enables the default language. This ensures the correct operation applications that do not support - HP 4550 | Service Manual - Page 272
for the I/O channel that delivered the command. For this printer, it duplicates the function of @PJL USTATUS JOB=OFF, AND @PJL USTATUS DEVICE=OFF. All commands not supported by this printer's PJL command set are returned with the message @PJL XXXX?. 270 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 273
the READY state. Interpreting the menu map The following sample illustrates the printer's menu map. Figure 7-11 4500 series menu map 1 Information Menu 2 Paper Handling Menu 3 Configuration Menu 4 Printing Menu 5 I/O Menu 6 Calibration Menu 7 Resets Menu C7085-90921 Chapter 7 Troubleshooting 271 - HP 4550 | Service Manual - Page 274
1 2 3 4 5 6 7 Figure 7-12 4550 series menu map 1 Information menu 2 Paper handling menu 3 Printing menu 4 Configuration menu 5 I/O menu 6 Calibration menu 7 Resets menu if a hard disk is installed) Note Some menus only appear when the hard disk is installed. 272 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 275
for the transfer belt, fuser, and imaging drum. Table 7-12 HP Color LaserJet 4550 Information Menu Menu item Description PRINT MENU MAP Prints the control panel menu map. PRINT CONFIGURATION Prints the printer configuration page. PRINT FONT LIST Prints the available PCL and PS (emulated - HP 4550 | Service Manual - Page 276
printer will pull media from Tray 1 regardless of the size and type of media loaded in the tray. To configure Tray 1 by size or type, it must be configured as TRAY 1 MODE=CASSETTE. Table 7-13 HP Color LaserJet 4500 **A-4 is the default for printers sold in Asia 274 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 277
Table 7-14 HP Color LaserJet 4550 Paper Handling Menu Menu item Values COLOR HEAVY CARDSTOCK TRAY 2 TYPE (same choices as TRAY 1 TYPE except LABELS and CARDSTOCK) TRAY 3 TYPE (same choices as TRAY 1 TYPE except LABELS and CARDSTOCK) MANUAL FEED ON OFF C7085-90921 Chapter 7 Troubleshooting - HP 4550 | Service Manual - Page 278
changed. Table 7-15 HP Color LaserJet 4500 Configuration settings Menu item Values Description POWERSAVE OFF 1 MIN (used for troubleshooting) 30 MIN 1 HR* 2 HRS 4 HRS 8 HRS The length of time before the printer goes into power-saving mode. PERSONALITY AUTO* PCL PS The personality (language - HP 4550 | Service Manual - Page 279
Table 7-16 HP Color LaserJet 4550 Configuration settings Menu item Values Description POWERSAVE OFF 1 MIN (used for troubleshooting) 15 MIN 30 MIN* 1 HR* 2 HRS 4 HRS The length of time before the printer goes into power-saving mode. CLEARABLE WARNINGS JOB* ON If ON, message appears until [ - HP 4550 | Service Manual - Page 280
default settings for a specific print job. Table 7-17 HP Color LaserJet 4500 Printing Menu settings Menu Item Values Description COPIES ORIENTATION FORM LENGTH DUPLEX1 BINDING2 PCL FONT SOURCE PCL FONT NUMBER PCL FONT PITCH3 PCL FONT POINT SIZE4 PCL SYMBOL SET COURIER APPEND CR TO LF 1 to 999 - HP 4550 | Service Manual - Page 281
Table 7-18 HP Color LaserJet 4550 Printing Menu settings Menu Item Values . PCL FONT SOURCE INTERNAL* SOFT SLOT n (n = 1,2,3) Instructs the printer where to look for PCL fonts. PCL FONT NUMBER 0 to 999 (default: 0) PCL FONT font is specified C7085-90921 Chapter 7 Troubleshooting 279 - HP 4550 | Service Manual - Page 282
Server Software Installation Guide. This guide is included with the HP Color LaserJet 4500N and 4500DN printers and the 4550N, 4550DN and 4550HDN printers, and is also available through HP Direct. (See Appendix D in the online user guide for ordering information.) 280 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 283
this menu to set toner densities, see page 250. Calibrating toner densities changes the color balance of your printer by altering halftones. It affects all print jobs. Notify your network administrator before performing this procedure. Table 7-21 HP Color LaserJet 4500 Calibration Menu settings - HP 4550 | Service Manual - Page 284
after the fuser kit has been replaced. Table 7-24 HP Color LaserJet 4550 Resets Menu settings Menu Item Description NEW [COLOR] CARTRIDGE Resets the toner gauge for the printer and allows printing to continue. NEW TRANSFER KIT Clears the maintenance message after the transfer kit has SELECT - HP 4550 | Service Manual - Page 285
or delete these jobs from the control panel. If there are no quick copy jobs stored on the printer's hard disk, this menu is not displayed on the control panel. Table 7-25 HP Color LaserJet 4550 Quick Copy Jobs menu Menu Item Values Description [JOBNAME] The name of the quick copy job defined - HP 4550 | Service Manual - Page 286
printer's hard disk, this menu is not displayed on the control panel. Table 7-26 HP Color LaserJet 4550 Private driver. The number of copies the user wants to print. 1-999: Prints the requested number of copies of the job. DELETE: Deletes the job from the printer's hard disk. 284 Troubleshooting - HP 4550 | Service Manual - Page 287
Troubleshooting tools Note Embedded Web server The embedded Web server allows you to view printer and network status and to manage printing functions from your PC instead of from the printer control panel. This service and above. IPX-based printer connections are not supported by the embedded Web - HP 4550 | Service Manual - Page 288
Identification page Name the printer and assign an asset number to it. Input the name and email address of the primary point of contact for information about the printer. This page also shows the printer's network names, addresses, and printer model information. 286 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 289
Server Administrator's Guide, go to http://www.hp.com/support/ lj4550. When you connect, select Manuals. Printer configuration page Printing a printer configuration page can help you verify that the printer is configured properly. This can be useful in troubleshooting printer problems. To print - HP 4550 | Service Manual - Page 290
10 Density settings-(Color LaserJet 4500 series only) Lists the current density settings. 11 Printing Menu-(Color LaserJet 4500 series only) Lists the current settings of the printing menu items. 12 Color blocks-The color blocks verify color printing ability of the printer. The color blocks in the - HP 4550 | Service Manual - Page 291
. Rows one to four are counted through the engine. Rows five and six are driver requests. The tray count is incremented based on the tray that is selected by the firmware, not the configuration page until the printer is ready or calibration will not occur. C7085-90921 Chapter 7 Troubleshooting 289 - HP 4550 | Service Manual - Page 292
life for the following printer consumables and kits: toner cartridges (all colors) drum kit transfer kit fuser kit It also lists useful printer information including the total number of pages printed (in monochrome and in color), the printer serial number, and the part numbers for the - HP 4550 | Service Manual - Page 293
pages that were printed on one side, the number that were printed on two sides (duplexed), and totals of the two printing methods for each media size. It also lists the average percentage of page coverage for each toner color. To print the usage page 1 On the printer control panel, press MENU until - HP 4550 | Service Manual - Page 294
log (4500 series) 1 Access the printer's service mode (see page 293). 2 Press [ITEM] until PRINT CONFIGURATION appears. 3 Press [SELECT] to print the configuration page. Up to 50 events will be printed on the configuration page. To print the event log (4550 series) 1 On the printer control panel - HP 4550 | Service Manual - Page 295
for the modification of page counts and certain registration values for the printer. In the 4500 series, when the configuration page is printed while in service mode all event log messages (up to 50 events) will be printed. In the 4550 series, the event log is printed from the Information menu. If - HP 4550 | Service Manual - Page 296
access to the Service Menu as well as other control panel menus and their settings. Figure 7-18 HP Color LaserJet 4500 series Service menu map 1 Service Menu 2 Information Menu 3 Paper Handling Menu 4 Configuration Menu 5 Printing Menu 6 I/O Menu 7 Calibration Menu 294 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 297
1 2 3 4 5 6 7 Figure 7-19 HP Color LaserJet 4550 series Service menu map 1 Information menu 2 Paper Handling Menu 3 Printing Menu 4 Configuration Menu 5 I/O Menu 6 Calibration Menu 7 Note Some menus only appear when the hard disk is installed. C7085-90921 Chapter 7 Troubleshooting 295 - HP 4550 | Service Manual - Page 298
key until transfer maintenance count appears. 2 Press the [VALUE +/-] key to set the number. 3 Press [SELECT] to save. 4 Repeat steps 2 and 3 to change the other numbers if required. Fuser maintenance count The fuser maintenance count functions the same way as other HP LaserJet printers. This count - HP 4550 | Service Manual - Page 299
. As with the color page count, the deal with color plane registration the service mode another printer. If Color Plane Registration might need to be checked. See the instructions below for printing a registration page. Registration offset has also occurred when a printer three other colors. Along - HP 4550 | Service Manual - Page 300
best number. Figure 7-20 Registration page Note Hewlett-Packard strongly recommends that the registration values be selected color (cyan, magenta, or yellow) at its registration number. 2 Press the [VALUE +/-] key to change the registration number to the one Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 301
Press the [ITEM] key to scroll through the service menu until top margin appears. 2 Press the and 3 are combined. The procedure is the same as the top margin with one exception. The page must be printed from the tray that will be adjusted. Printing ] key. C7085-90921 Chapter 7 Troubleshooting 299 - HP 4550 | Service Manual - Page 302
printer and the HP Color LaserJet 4550/4550N/4550DN/4550HDN printer. Take caution when performing printer diagnostics to avoid risk of injury. Only trained service personnel should access the diagnostics mode with the skins removed. There are two diagnostic sections built into the firmware, one - HP 4550 | Service Manual - Page 303
CAUTION Do not interrupt the NVRAM test. Doing so will cause the printer to lose all NVRAM values. EXECUTE TESTS In almost all cases, when NVRAM values are being lost. In the 4550 series only, [CANCEL JOB] will abort the test. Do not turn off the printer or corruption of the NVRAM could result; if - HP 4550 | Service Manual - Page 304
These diagnostics are available as tools to help isolate problems that are not reported by the firmware. As mentioned previously, no error message will appear if there is a problem in the section being tested. A good understanding of how the printer operates is required to use the engine diagnostics - HP 4550 | Service Manual - Page 305
service view of the carousel and the toner cartridge sleeves, remove the drum cartridge. The drum drawer must be closed before the drum turn if it is installed, as well as the drive gear for the ITB. Drum test The drum test exercises the drum drive mechanism. Also, the fuser 7 Troubleshooting 303 - HP 4550 | Service Manual - Page 306
then there is a possible problem. Identify the sensor or service personnel to open and close doors on the printer while Drum detect Description Front and rear door switches ITB drawer switch Toner cartridge door * Drum drawer switch * Detect if a drum cartridge is installed 304 Troubleshooting - HP 4550 | Service Manual - Page 307
(A) as well when opened. Description Detects if fuser is installed. Changes state if not detected or drawers should be closed. In this state the display will show all 0's. Open the doors and drawers one at a time to verify correct functionality. If operating correctly, the 0 will change to a 1. If - HP 4550 | Service Manual - Page 308
Can be activated with the formatter PCB removed. For the printer to perform an engine test, tray 2 must be installed and loaded with paper, and the toner cartridge must be installed in the printer. Engine test button Figure 7-21 Location of the engine test button 306 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 309
. Total page count and total color page count (the counter is reset to 0) Transfer kit percentage of life remaining (gauge is reset to 100 percent) Fuser kit percentage of life remaining (gauge is reset to 100 percent) Printer serial number C7085-90921 Chapter 7 Troubleshooting 307 - HP 4550 | Service Manual - Page 310
Diagrams This section contains wiring diagrams and photos of all internal printer components. PS3101 PS10 PS3102 PS12 PS3103 PS9 PS7 PS6 PS11 paper full sensor PS10 Carousel home position sensor PS11 Toner cartridge press sensor PS12 Toner level sensor 308 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 311
Side registration home position sensor CTLS Continuous toner level sensor CL2 CL3 CL1 CL4 SL2 SL1 Figure 7-23 Printer solenoids and clutches Table 7-33 Solenoid and ITB cleaning roller separation clutch CL4 Secondary transfer roller separation clutch C7085-90921 Chapter 7 Troubleshooting 309 - HP 4550 | Service Manual - Page 312
M2 Pick-up motor M3 Carousel motor (carousel drive unit) M4 Drum motor (drum drive unit) M5 Toner cartridge motor Fan Motors FM1 Large fan FM2 Small fan FM3 Fan (upper front cover fan) CL1 PS1 PS2 PS301 Figure 7-25 Miscellaneous sensors and clutches 310 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 313
wall) 2 Cleaning Roller 1 Figure 7-26 Intermediate transfer belt sensors Table 7-36 Intermediate transfer belt sensors Name Description 1 Intermediate transfer belt (end of life lever) 2 Intermediate transfer belt (home position sensor) (PS5) C7085-90921 Chapter 7 Troubleshooting 311 - HP 4550 | Service Manual - Page 314
PS7 sensor location Table 7-38 PS6 and PS7 description Name Description PS6 Fusing assembly pressure sensor PS7 Paper exit sensor (access through the opening) 312 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 315
removed) SW2 SW5 PS13 Figure 7-30 Miscellaneous switches and sensors Table 7-40 SW2, SW5, and PS13 description Name Description SW2 Top cover (toner door) switch SW5 Top cover/rear door +24V interrupt switch PS13 Waste toner full sensor C7085-90921 Chapter 7 Troubleshooting 313 - HP 4550 | Service Manual - Page 316
9 8 6 5 Figure 7-32 Miscellaneous parts Table 7-42 Miscellaneous parts Location Name 1 Drum ground connector 2 Drum drawer closed switch (SW3) 3 Front drawers drum/ITB +24V interrupt switch (SW4) 4 ITB drawer closed switch (inside chassis wall) (SW1) 314 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 317
parts Location Name 5 Tray 2 pickup solenoid (behind chassis wall) (SL2) 6 Secondary transfer roller clutch (CL4) 7 Pickup motor (M2) 8 ITB contact/separation clutch (behind lower gear) (CL2) 9 Fusing motor (M1) 10 Paper feed PCB 11 Cleaning roller cam clutch (CL3) 12 Toner - HP 4550 | Service Manual - Page 318
Press to defeat Figure 7-34 Rear door interlock switch defeat Figure 7-35 Right rear fan 316 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 319
2B 3B 4B 4 Figure 7-37 Fusing assembly Table 7-45 110-volt fusing assembly Location Description Pin 1 Frame ground Pins 2 to 4 6.3 ohms ± 1 ohm C7085-90921 Chapter 7 Troubleshooting 317 - HP 4550 | Service Manual - Page 320
) 1B to 2B 310 K to 430 K ohm at (room temperature) 3B to 4B Short 110-volt unit Figure 7-38 DC controller PCB connectors Rear of printer Front of printer 318 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 321
Figure 7-39 Note: Some locations will vary slightly depending on the version of the printer. Location of connectors C7085-90921 Chapter 7 Troubleshooting 319 - HP 4550 | Service Manual - Page 322
Figure 7-40 Note: Some locations will vary slightly depending on the version of the printer. Location of duplexer and 500-sheet paper feeder connectors 320 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 323
Figure 7-41 500-sheet feeder wiring diagram C7085-90921 Chapter 7 Troubleshooting 321 - HP 4550 | Service Manual - Page 324
322 Troubleshooting C7085-90921 - HP 4550 | Service Manual - Page 325
8 Parts and diagrams Chapter contents Introduction 324 Ordering parts 325 Consumables, accessories, and supplies 325 Common fasteners 328 Illustrations and parts lists 329 Alphabetical parts list 355 Numerical parts list 359 C7085-90921 Chapter 8 Parts and diagrams 323 - HP 4550 | Service Manual - Page 326
(item number), the associated part number, quantity, and description of each part. When looking for a part number, pay careful attention to the voltage listed in the description column to ensure that the part number selected is for the correct printer model. 324 Parts and diagrams C7085-90921 - HP 4550 | Service Manual - Page 327
92215N LocalTalk cable kit 92215S Consumable items DIN-8 printer cable (for Macintosh computers) C4195A R94-4001-410CN Drum kit C4196A R96-5009-000CN Transfer kit C4197A R96-5007-000CN Fuser kit (110V) C4198A R96-5008-000CN Fuser kit (220V) 5090-3379 Localized font DIMMS Toner cloths - HP 4550 | Service Manual - Page 328
C4083A C4083-67901 Duplex unit (two-sided printing) C4235A HP Color LaserJet 4500 cabinet J6054A 5 GB Hard Disk (4550 series only) C4103A Fast Infrared Pod (4550 series only) C4286A Panel overlays Flash firmware DIMM (4550 series only) C4084-40001 English C4084-40005 German C4084 - HP 4550 | Service Manual - Page 329
Reference Materials Japanese 5963-7863 HP LaserJet Printer Family Print Media Guide 5961-0976 HP PCL/PJL Reference Set 5969-6818 HP JetDirect Print Server Administrator's Guide Toner supplies 5969-3412 HP JetDirect Print Server JetAdmin Setup Guide C4191A R94-4005-410CN Black C4192A - HP 4550 | Service Manual - Page 330
, (ex. the skins) To hold plastic to plastic, (ex. control panel) Sheet metal to sheet metal, (ex. formatter pan) To hold gears into place 328 Parts and diagrams C7085-90921 - HP 4550 | Service Manual - Page 331
an older version of the HP Color LaserJet 4500 printer. The HP Color LaserJet 4550 series printer is equivalent to the newer version of the HP Color LaserJet 4500 series printer, unless otherwise noted, although it does have some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 332
1 2 3 Figure 8-1 4 5 Assembly location diagram (1 of 2) 1 Fuser assembly 2 Intermediate Transfer Belt assembly 3 Paper path and trans port 4 Feeder assembly 5 Transfer assembly 330 Parts and diagrams C7085-90921 - HP 4550 | Service Manual - Page 333
1 2 Figure 8-2 3 Assembly location diagram (2 of 2) 1 Cartridge carousel and housing assembly 2 Carousel drive assembly 3 Toner cartridge carousel assembly C7085-90921 Chapter 8 Parts and diagrams 331 - HP 4550 | Service Manual - Page 334
1 9 2 8 7 3 6 4 5 Figure 8-3 PCB locations 332 Parts and diagrams C7085-90921 - HP 4550 | Service Manual - Page 335
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 336
11 10 1 2 12 3 4 5 9 8 7 6 Figure 8-4 External covers, panels, etc. 334 Parts and diagrams C7085-90921 - HP 4550 | Service Manual - Page 337
CAUTION Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. Note Early CLJ4500 - HP 4550 | Service Manual - Page 338
versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. 336 Parts and diagrams C7085 - HP 4550 | Service Manual - Page 339
-000CN 11 Fuser, 110V 1 RG5-5154-050CN C4084-69002* Parts for 4500 series xxH... and above N/A RG5-5187-000CN RH3-2219-000CN RH3-2220-000CN RG5-5165-000CN RB2-1556-000CN RG5-5173-060CN RG5-5120-100CN RB2-1361-000CN RB2-1283-000CN RH7-1407-000CN RG5-5154-050CN C4084-69002* Parts for 4550 series - HP 4550 | Service Manual - Page 340
versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. 338 Parts and diagrams C7085 - HP 4550 | Service Manual - Page 341
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 342
14 -A 14 -B 1 2 13 12 11 3 10 9 8 7 (SW3) Figure 8-8 Internal components (3 of 3) 4 5 6 340 Parts and diagrams C7085-90921 - HP 4550 | Service Manual - Page 343
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 344
1 14 13 12 11 10 32 4 5 15 6 16 7 8 17 9 Figure 8-9 Developing carousel assembly 342 Parts and diagrams C7085-90921 - HP 4550 | Service Manual - Page 345
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 346
5 4 3 1 2 7 6 Figure 8-10 Paper pick-up assembly (1 of 3) 344 Parts and diagrams C7085-90921 - HP 4550 | Service Manual - Page 347
6 ITB drawer connector 1 VS1-6174-014CN 7 ITB cable 1 RG5-3786-000CN Parts for 4500 series xxH... and above RG5-4651-000CN WC2-5330- Parts for 4550 series RG5-4651-000CN WC2-5330-000CN FH7-7313-000CN WG8-5309-000CN RG5-5117-000CN VS1-6174-014CN RG5-3786-000CN C7085-90921 Chapter 8 Parts - HP 4550 | Service Manual - Page 348
12 Bushing 2 RS5-1293-000CN Parts for 4500 series xxH... and above RS6- 0158-000CN RS6-0157-000CN RS6-0156-000CN RS6-0158-000CN RF5-2092-000CN RS6-0140-000CN RS6-0141-000CN RG5-5119-000CN RS6-0135-000CN RS6-0135-000CN RS6-0134-000CN RS5-1293-000CN Parts for 4550 - HP 4550 | Service Manual - Page 349
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 350
assembly (3 of 3) Table 8-12 Paper pick-up assembly (3 of 3) Ref. Description Qty. Parts for 4500 series xxG... and below 1 Cable, fusing/option 1 RG5-3787-000CN 2 Lever, sensor 1 RB2-0576-000CN 3 Clutch, one-way 1 RB2-0572-000CN 4 Gear, 18T 1 RS6-0139-000CN 5 Roller, paper pick - HP 4550 | Service Manual - Page 351
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 352
versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. 350 Parts and diagrams C7085 - HP 4550 | Service Manual - Page 353
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 354
versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. 352 Parts and diagrams C7085 - HP 4550 | Service Manual - Page 355
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. C7085-90921 Chapter - HP 4550 | Service Manual - Page 356
... and above C4083-67901 RG5-4055-000CN Parts for 4550 series C4083-67901 RG5-4055-000CN CAUTION Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329 - HP 4550 | Service Manual - Page 357
Two versions of the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. Table 8-18 Alphabetical - HP 4550 | Service Manual - Page 358
-5170-000CN RG5-3325-040CN RG5-3296-030CN RG5-3319-000CN RG5-5142-000CN RG5-5142-000CN RG5-3170-000CN C4083-67901 RG5-4055-000CN Parts for HP Color LaserJet 4550 printer RB2-0916-000CN RG5-5152-000CN RG5-3320-000CN RG5-5151-000CN RB2-1206-000CN RB2-1572-000CN RB2-1205-000CN RG5-3310-000CN - HP 4550 | Service Manual - Page 359
Guide, cable RB2-1277-000CN Guide, cable, lower RB2-1456-000CN Guide, upper drum drawer RB2-1457-000CN cable Kit, carousel flap C4084-67909 Kit, fuser deflector C4084-67906 Kit, imaging drum drawer RG5-5230-000CN Laser 000CN Parts for 4500 series Parts for HP Color LaserJet 4550 printer - HP 4550 | Service Manual - Page 360
support RB2-1556-000CN Transfer assembly, secondary RG5-3235-000CN Transfer cam assembly RG5-3240-000CN Tray, extension RB2-1215-000CN *These parts require exchange Parts for 4500 -000CN RG5-5118-000CN RB2-1215-000CN Parts for HP Color LaserJet 4550 printer RF5-2094-000CN RF5-2095-000CN N/A - HP 4550 | Service Manual - Page 361
the HP Color LaserJet 4500 series printers are available. Before ordering parts, you will need to identify which printer version you are servicing. For more information, see page 329. The 4550 series has some different service parts from the 4500 series. Table 8-19 Numerical parts list Part number - HP 4550 | Service Manual - Page 362
Guide, cable, lower RB2-1457-000CN Guide, upper drum drawer cable RB2-1556-000CN Strap, cover support RB2-5185-000CN Bushing, ITB, left RF5-1885-000CN Roller, separation RF5-1885-000CN Roller, separation RF5-2076-000CN Cover, toner access RF5-2092-000CN Roller RF5-2112-000CN Roller, transfer - HP 4550 | Service Manual - Page 363
RG5-3319-000CN Drum bushing assembly RG5-3320-000CN Cover, ITB drawer RG5-3325-040CN Door, rear access RG5-3345-000CN Control panel assembly RG5-3355-000CN Sensor (PS12), toner assembly RG5-3400-210CN Cassette, 250-sheet RG5-3781-000CN Cable, main RG5-3782-000CN Cable, laser RG5-3783-000CN - HP 4550 | Service Manual - Page 364
RG5-5230-000CN Kit, imaging drum drawer RG5-5232-000CN Cover, drum drawer RG5-5247-000CN Continuous toner level sensor RG5-5249-000CN Carousel assembly RG5-5254-000CN DC controller PCB RG5-5254-000CN DC controller PCB RG5-5444-000CN Cable, level sensor RH2-5334-000CN Cable, laser (flat) RH2 - HP 4550 | Service Manual - Page 365
Table 8-19 Numerical parts list Part number Description RS5-1293-000CN Bushing RS5-1341-000CN Cone RS5-2739-000CN Spring, toner flap RS5-2754-000CN Spring, tension RS5-2794-000CN Spring, Tray 2 pickup tension RS5-2799-000CN Spring, tension RS5-2800-000CN Spring, tension RS5-6210- - HP 4550 | Service Manual - Page 366
(PS4), multi-purpose tray paper WG8-5362-000CN Sensor (PS10), carousel position WG8-5364-000CN Sensor (PS3), last paper XG9-0361-000CN Bearing, carousel *These parts require exchange Figure Reference not shown 8-10 6 8-8 7 8-10 2 8-11 32 8-10 4 8-14 4 8-9 10 8-14 3 8-9 3 364 - HP 4550 | Service Manual - Page 367
labels printing 32 supported sizes 29 adjusting colors automatic 246 balance cable connecting 59 pin configuration 60 specifications 58 troubleshooting 268 black lines, troubleshooting 255, 261 black pages, troubleshooting 255, 257 black toner cartridges density setting 252 installing 51, 54 part - HP 4550 | Service Manual - Page 368
variation 244 Color LaserJet 4500 family printer models 14 Color LaserJet Transparencies, ordering 326 color print speed 17 colored paper 31 ColorLaserJet Soft Gloss Paper 326 colorless output, troubleshooting 257 ColorSmart II 246 commands DOS 269 PJL 269 Commercial Service and Support Organization - HP 4550 | Service Manual - Page 369
drive assemblies, removing carousel 179 drum 176 drivers, printer color output 244 ordering 43 settings 69 dropouts, troubleshooting 257 drum drawer assembly, removing 163 cover, removing 149 locating 25 versions 335 drum drive assembly, removing 176 drum kits life span 83 ordering 325 replacement - HP 4550 | Service Manual - Page 370
with 15 ordering 326 supported media 30 duplexing drum life 80 glossy manual 124 paper path 122 filters locating 84 replacing 91 Finnish laser safety statement 38 FIR (Fast InfraRed Receiver) 68 firmware replacing 307 upgrading 98 flags 118, 119 flat-blade screwdrivers 140 flowchart, troubleshooting - HP 4550 | Service Manual - Page 371
Media Guide 28 HP LaserJet Utility for Macintosh 70 HP LocalTalk Cable Kit 72 HP PCL 17 HP Support Assistant 42 HP Toner Cleaning Cloth 78 HP-UX 72 hubs, rollers 94 humidity site requirements 20, 22 storing consumables 23 I I/O Menu 280 I/O switching 58 IBM OS/2 LAN servers 72 ICC color profiles - HP 4550 | Service Manual - Page 372
, security 74 life span consumables 83 imaging drum 80 ITB 114, 296 kits 142 photosensitive drum cartridge 112 status page, printing 290 toner cartridges 83, 142 lift cams 114 lifting printer 49 light print, troubleshooting 259 light, affects on color variation 244 light-emitting diodes (LEDs) 111 - HP 4550 | Service Manual - Page 373
colors 260 model numbers 18 models drum drawers 335 HP LaserJet 4500 14, 140 modes diagnostics 300 service 293 monitors, affect on color 244 registration) 129, 130 M4 (drum) 134 M5 (toner cartridge) 118, 134 removing 185, 187 mottled output, troubleshooting 260 moving printer 49 MS-DOS commands 269 - HP 4550 | Service Manual - Page 374
developing 159 formatter 169 paper feed 183 paper size switch 181 PCL support 17 perforations 30 Phillips screwdrivers 140 phone numbers Commercial Service ans Support Organizations 41 HP Distribution Center 43 ordering parts 41 ordering supplies 325 photoconductive material 105, 106 photodiodes 111 - HP 4550 | Service Manual - Page 375
transfer 107 print in grayscale option 246 print jobs monochrome, affect on drum life 81 settings 278 short 80 print media guide 28 printer drivers color output 244 ordering 43 settings 69 Printer Job Language (PJL) commands 269 Technical Reference Manual 75 printer language support 17 printer - HP 4550 | Service Manual - Page 376
replacing air filters 91 consumables 83, 85 fuser 92 fuser kit 92 gears 193 imaging drum 88 ITB 90 paper rollers 94 parts 139 toner cartridges 86 transfer kits 89 reservoir, waste toner 109 Resets Menu 282 resetting printer 97 retaining ring screws 141 reversed paper sensor (PS3101) 122, 129 - HP 4550 | Service Manual - Page 377
printer operation 62 text, troubleshooting 257, 262 theory of operations clutches 114 duplex unit 128 fusing 110 image formation system 104 ITB 113 laser/scanner 120 paper path 122 secondary transfer roller 115 toner carousel 118 waste toner cleaning 109, 113 ThinLan cables 65 TIFF files 249 toner - HP 4550 | Service Manual - Page 378
report, printing 290 transfer maintenance count 296 transfer operations 107 transfer plates, waste toner 109 transfer roller cleaning 78 locating 84 operations 114 removing 207 replacing 89 transparencies defects, troubleshooting 263 detection sensor (PS301) 125 HP-supported 30 ordering 326 print - HP 4550 | Service Manual - Page 379
PS13) 113, 313 wavy characters, troubleshooting 262 Web server, embedded 285 websites HP 15 HP JetAdmin software 70 Material Data Safety Sheet (MSDS) 37 PANTONE palettes 249 product and support information 42 service part information 42 specifications 22 weight media 29 printer 20, 23 wheel assembly - HP 4550 | Service Manual - Page 380
378 Index C7085-90921 - HP 4550 | Service Manual - Page 381
- HP 4550 | Service Manual - Page 382
copyright © 2000 Hewlett-Packard Company www.hp.com/support/lj4550 english *C7085-90921* *C7085-90921* C7085-90921
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hp
color LaserJet
4550/4500 series
service
manual
achieve