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HP Color LaserJet CM4730 Service Manual - Page 189

Step 2: Primary charging, Step 3: Laser beam exposure, Development block, Step 4: Development

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Step 2: Primary charging To prepare for latent image formation, the surface of the photosensitive drum is charged with a uniform negative potential. The charging method of this MFP is to charge directly to the photosensitive drum surface from the primary charging roller, which is interlocked with the drum. The primary charging roller is made of a conductive rubber. To charge the drum surface negatively, the DC bias is applied to the primary charging roller. Step 3: Laser beam exposure In this step, the latent image is formed on the photosensitive drum by the laser beam. As the laser beam scans on the negatively charged photosensitive drum, the potential on the exposed area is neutralized and the negative potential is removed from the drum surface. This area forms an electrostatic latent image. Laser beam Exposed area Unexposed area Figure 4-20 Laser beam exposure Development block The second part of the image formation process is the development block, where toner is transferred onto the electrostatic latent image on the surface of the photosensitive drum to create a visible image. This MFP uses a contact development method that keeps the developing cylinder in contact with the drum, pushing the toner against the drum surface for development. The toner is nonmagnetic and consists of resins. Step 4: Development In this step, the toner adheres to the electrostatic latent image on the photosensitive drum surface. The toner (developing material) has an insulating property and is charged with a negative potential by the friction force with the rotating developing cylinder and the developing blade surface. This negatively charged toner contacts with the photosensitive drum, after the potential is adjusted to be uniform. As the area of the drum surface where the laser beam exposed has higher potential than the developing cylinder, the toner charged with almost the same potential with the developing cylinder adheres to this area. This phenomenon is called contact development and it visualizes the electrostatic latent image on the drum surface. ENWW Image formation system 169

Section	Page
Product information	21
Product comparison	22
HP Color LaserJet CM4730 MFP	22
HP Color LaserJet CM4730f MFP	23
HP Color LaserJet CM4730fsk MFP	23
HP Color LaserJet CM4730fm MFP	24
Product features	25
Product walkaround	29
Front view	29
Back view	30
Interface ports	31
Serial number and model number location	31
Media specifications	33
Understand paper and print media use	33
Supported paper and print media sizes	33
Custom paper sizes	35
Special paper or print media guidelines	35
Information pages	36
Installation	39
Installation checklist	40
Unpacking the MFP	42
Connecting power	46
Installing print cartridges	47
Installing a new control panel overlay	49
Install memory and print server cards	50
Install memory and fonts	50
Install DDR memory DIMMs	50
Install a flash memory card	50
Enabling memory	51
Install an HP Jetdirect or EIO print server card	51
Test the MFP operation	55
Sleep and wake	56
Connecting to a computer or network	57
Parallel connection	57
USB connection	58
Auxiliary connection	59
Fax connection	60
Analog faxing	60
Connecting the fax accessory to a phone line	60
Configuring and using the fax features	61
Digital faxing	61
Printer software	62
Software for Windows	62
Supported Windows versions	62
Install the printing-system software	62
Install Windows printing-system software for direct connections (USB or parallel)	63
Install Windows printing-system software for networks	63
Use Windows-sharing on a network	64
Install the software after the parallel or USB cable has been connected	64
Supported printer drivers	64
Remove software for Windows	65
Select the correct printer driver	65
Universal printer drivers	65
Driver Autoconfiguration	65
Update Now	67
Priority for print settings	67
Open the printer drivers	68
Software for Macintosh	68
Software for Macintosh computers	68
Install software for Macintosh	69
Install Macintosh software for direct connections (USB)	69
Install Macintosh software for networks	70
Remove software from Macintosh operating systems	70
Software for other operating systems	70
HP Web Jetadmin	70
UNIX	71
Network utilities	71
HP Web Jetadmin	71
Embedded Web server	72
HP Easy Printer Care software	73
Other components and utilities	73
Network configuration	74
Configure TCP/IPv4 parameters	74
Change the IP address	74
Set the subnet mask	75
Set the default gateway	75
Configure TCP/IPv6 parameters	76
Disable network protocols (optional)	76
Disable IPX/SPX	76
Disable AppleTalk	77
Disable DLC/LLC	77
HP Jetdirect EIO print servers	77
Security features	78
Secure the embedded Web server	78
Foreign Interface Harness (FIH)	78
Requirements	78
Using the FIH	78
Enable the FIH portal	78
Disable the FIH portal	79
Secure Disk Erase	79
Data affected	79
Gaining access to Secure Disk Erase	80
Additional Information	80
Job storage features	80
DSS authentication	80
Locking the control panel menus	80
Locking the formatter cage	81
Optional output and input devices	82
Manage and maintain	83
Control-panel menus	84
Use the control panel	84
Control-panel layout	84
Home screen	85
Buttons on the touchscreen	86
Control-panel help system	86
Navigate the Administration menu	86
Information menu	87
Default Job Options menu	88
Default Options for Originals	89
Image adjustment	90
Default Copy Options	91
Default Fax Options	92
Default E-mail Options	93
Default Send to Folder Options	94
Default Print Options	95
Time/Scheduling menu	95
Management menu	97
Initial Setup menu	98
Networking and I/O	99
Fax Setup	106
E-mail Setup	109
Send Setup menu	109
Device Behavior menu	109
Print Quality menu	114
Troubleshooting menu	116
Resets menu	120
Service menu	120
Management tools	122
Information pages	122
HP Easy Printer Care software	122
Supported operating systems	122
Open HP Easy Printer Care software	122
HP Easy Printer Care software sections	122
Embedded Web server	124
Open the embedded Web server	124
Information tab	125
Settings tab	125
Digital Sending tab	126
Networking tab	126
Other links	126
HP Web Jetadmin software	127
HP Printer Utility for Macintosh	127
Open the HP Printer Utility	127
Print a cleaning page	128
Print a configuration page	128
View supplies status	128
Order supplies online and use other support features	129
Upload a file to the printer	129
Update the firmware	129
Activate the two-sided printing (duplexing) mode	129
Lock or unlock printer storage devices	130
Save or print stored jobs	130
Configure trays	130
Change network settings	131
Open the embedded Web server	131
Set up e-mail alerts	131
Approximate replacement intervals for supplies	132
ETB life under different circumstances	133
Managing print cartridges	134
HP print cartridges	134
Change print cartridges	134
Non-HP print cartridges	134
Print cartridge authentication	134
Print cartridge storage	135
Print cartridge life expectancy	135
Checking the supply level	135
Using the product control panel	135
Using the embedded Web server	135
Using HP Web Jetadmin	135
Replacing supplies	136
Locate supplies	136
Supply replacement guidelines	136
Making room around the MFP for replacing supplies	136
Replacing the ETB	137
Replacing the fuser	137
Replacing the stapler cartridge	138
Using the cleaning page	140
Clean the MFP	141
Clean the outside of the MFP	141
Clean the touchscreen	141
Clean the scanner glass	141
Cleaning the ADF delivery system	142
Clean the ADF delivery system	142
Clean the ADF rollers	143
Clean the mylar strip	146
Performing preventive maintenance	148
ADF maintenance kit	148
Calibrate the scanner	149
Set the real-time clock	150
Set the date format	150
Set the date	150
Set the time format	150
Set the time	150
Theory of operation	153
Basic operation	154
Operation sequence	155
Operation sequence (scanner)	155
Power on sequence	156
Formatter system	158
Sleep mode	158
Image Resolution Enhancement technology (REt)	159
Input/Output	159
Parallel interface	159
USB 2.0 connector	159
ACC accessory port	159
Flash	160
Hard disk	160
CPU	160
FIH (foreign interface harness)	160
MFP memory	160
Read-only memory	160
Random-access memory	160
DIMM slots	160
Flash memory	160
Nonvolatile memory	161
PJL overview	161
PML	161
Control panel	161
Scanner interface	161
Engine control system	162
DC controller PCB	162
Block operation	164
Motors, fans, and environment sensor	164
Failure detection	167
Drum motor failure detection	167
Fuser motor failure detection	167
ETB motor failure detection	167
Rear exhaust fan failure detection	167
Cartridge fan failure detection	167
Delivery fan failure detection	167
Power supply fan failure detection	168
Scanner fan failure detection	168
ADF fan failure detection	168
Control fans #1 and #2 failure detection	168
Sub power supply fan failure detection	168
ETB fan failure detection	168
Low-voltage power supply	168
Fuser control circuit	169
Low-voltage power supply circuit	171
Protective functions	172
Safety	172
Sleep mode	172
Power supply recognition	172
Heater temperature control	172
Initial rotation temperature control	173
Start-up temperature control	173
Print temperature control	174
Between-sheets temperature control	174
Temperature protective function	174
Protective function by the CPU	174
Protective function by the fuser heater safety circuit	174
Protective function by the thermoswitch	175
Temperature failure detection	175
Start-up failure (warm-up failure)	175
Abnormal low temperature of main thermistor (no conduction)	175
Abnormal high temperature of main thermistor	175
Abnormal low temperature of sub thermistor (no conduction)	175
Abnormal high temperature of sub thermistor	176
Drive circuit abnormality	176
High-voltage power supply	176
Generation of biases	177
Sub power supply assembly	179
Video interface control	179
Laser/scanner system	181
Laser control	182
Scanner control	183
Image formation system	185
Image formation process	186
Electrostatic latent image formation block	188
Step 1: Pre-exposure	188
Step 2: Primary charging	189
Step 3: Laser beam exposure	189
Development block	189
Step 4: Development	189
Transfer block	190
Step 5: Attraction	190
Step 6: Transfer	190
Step 7: Separation	191
Fusing block	191
Step 8: Fusing	191
Cleaning block	192
Step 9: Drum cleaning	192
Print cartridges	192
Memory tag	194
Cartridge presence detection	194
Memory tag detection	194
Photosensitive drum detection	194
Developing cylinder disengaging control	195
ETB (electrostatic transfer/transport belt)	195
Transfer roller (Y, C, M) engagement/disengagement detection	197
Transfer roller engagement/disengagement control	197
Calibration and cleaning	198
ETB cleaning	199
Color misregistration corrective control	200
Color misregistration detection	201
Image stabilization control	202
Environmental change control	203
Image density calibration control (DMAX)	204
Image halftone calibration control (DHALF)	204
Image density detection	204
Pickup/feed system	206
Pickup/feed unit	211
Cassette detection and cassette media size detection	211
Cassette pickup operation	212
Media lifting operation	212
Initial lift	213
Lift-up during printing	213
Multiple-feed prevention	214
Skew correction	215
Media detection	216
Feed speed control	217
Fusing and delivery block	218
Loop control	219
Fusing pressure release mechanism	220
Duplex feed unit	221
Duplexing reverse/duplexing feed operation	222
Jam detection	224
Pickup delay jam	225
Pickup stationary jam	225
Delivery delay jam	225
Door open jam	225
Residual paper jam	225
Reversing unit jam 1	226
Reversing unit jam 2	226
Duplexing pickup unit jam 1	226
Automatic delivery function	226
Scanner system	227
Electrical system	227
Motors and fans	228
Optical assembly	229
ADF feed system	230
ADF jam detection	231
Residual media jam	231
ADF pickup jam	231
ADF jam	231
Registration sensor jam	232
Read sensor jam	232
Exit sensor jam	232
ADF cover-open jam	232
ADF open jam	232
2 X 500-sheet paper feeder	233
Pickup and feed operations	234
2 X 500-sheet jam detection	236
Output devices	237
IPTU	237
IPTU transfer operation	238
IPTU jam detection	240
Pickup delay jam	240
Pickup stationary jam	240
Delivery delay jam	240
Delivery stationary jam	240
3-bin mailbox system	240
Stacker mode	242
Mailbox mode	242
Function-separator mode	242
Jam detection	242
Feed-delay jam	243
Feed-stationary jam	243
Residual-media jam	243
Power-on sequence	243
MBM driver	244
MBM switches and sensors	247
MBM PCBs	248
MBM list of signals	249
Stapler/stacker system	250
Power-on sequence	251
Staple mode	252
Jogger operation	258
Jogger home-position detection	262
Stacker mode	264
Jam detection	264
Stapler unit	265
Staple home position detection	265
Self-priming detection	266
Staple level detection	266
Stapler/stacker switches and sensors	267
Stapler/stacker motors, solenoid, and fan	269
Stapler/stacker PCBs	270
Stapler/stacker driver PCB	273
Stapler/stacker driver list of signals	275
Removal and replacement	279
Removal and replacement strategy	280
Required tools	280
Before performing service	281
After completing service	281
Screws used in the MFP	282
Service approach	283
User-replaceable parts	284
Print cartridges	285
Control panel overlays	287
Control panel	287
Intermediate paper transfer unit (IPTU)	289
Stapler/stacker	290
Staple cartridge	292
3-bin mailbox	294
ETB assembly, removing	295
MP tray pickup assembly	298
Trays 2, 3, and 4	298
ADF input tray	299
ADF pickup and feed rollers	301
ADF separation pad	303
ADF delivery guide (clear mylar sheet)	305
Face-down tray assembly	307
Fuser	308
Tray 2, 3, or 4 pickup and feed rollers	309
MP tray pickup roller	310
Tray 2 separation roller	312
Tray 3 or 4 separation rollers	314
Scanner filter cover and scanner filter	315
ADF hinge flap	316
Formatter board	317
Hard drive	319
DIMMs	320
Flash memory card (firmware)	326
Fax accessory	327
Covers, doors, and external panels	330
Face-down tray assembly	332
Delivery cover assembly	332
Rear cover assembly	333
Left cover assembly	335
Front cover assembly	336
Tray 1	339
Right lower cover assembly	342
Delivery upper cover assembly	345
Right front inner lower cover assembly	346
Left rear inner cover assembly	346
Right front inner upper cover assembly	347
Right rear inner cover assembly	349
Main assembly (internal assemblies)	352
Paper feed assembly	355
Pickup drive assembly	359
Lifter drive assembly	360
Disengaging drive assembly	362
Main drive assembly	364
Rail holder assembly	379
Rail guide assembly	381
Formatter case assembly	384
Laser/scanner components	390
Duplexing assembly	397
Delivery assembly	399
Fuser drive assembly	407
Motors and fans	408
Drum motors	408
Fuser motor	409
Fuser pressure release motor	410
Developing disengaging motor	415
Pickup motor assembly	416
Power supply fan	417
Cartridge fan	419
Sub power supply fan	420
Delivery fan	422
Control fan 1	423
Control fan 2	424
Rear exhaust fan	425
ETB fan	426
PCBs	430
DC controller PCB	430
Toner level PCB	435
High-voltage power supply PCB	435
Low-voltage power supply PCB	441
Memory controller PCB	446
Sub power supply PCB	447
Fan drive PCB	449
Switches, contacts, and sensors	450
High-voltage contacts	450
E-label memory contacts and cable	451
Power switch assembly	452
Door-open switch assembly	454
Environment sensor	455
ADF and scanner components	457
ADF assembly	457
Top covers	459
Scanner assembly	460
Scanner left cover	462
Scanner right cover	463
Scanner controller PCB	465
ADF components	466
ADF output bin extension	467
ADF white mylar backing	468
ADF front cover	471
ADF rear cover	472
ADF left side cover	474
ADF jam access cover and latch	475
ADF leading-edge and paper-present sensors	477
ADF hinges	478
2 X 500-sheet paper input assembly components	480
Rear cover	481
Right front cover	482
Left front cover	483
Right cover	484
Left cover	486
Right lower cover assembly	488
Pickup motor assembly	489
Upper lifter drive assembly	490
Lower lifter drive assembly	491
Upper pickup drive assembly	493
Lower pickup drive assembly	493
Upper pickup assembly	494
Lower pickup assembly	500
Paper feeder door-open switch	503

Match case Limit results 1 per page

Step 2: Primary charging

To prepare for latent image formation, the surface of the photosensitive drum is charged with a

uniform negative potential.

The charging method of this MFP is to charge directly to the photosensitive drum surface from the

primary charging roller, which is interlocked with the drum. The primary charging roller is made of a

conductive rubber. To charge the drum surface negatively, the DC bias is applied to the primary

charging roller.

Step 3: Laser beam exposure

In this step, the latent image is formed on the photosensitive drum by the laser beam. As the laser

beam scans on the negatively charged photosensitive drum, the potential on the exposed area is

neutralized and the negative potential is removed from the drum surface. This area forms an

electrostatic latent image.

Laser beam

Unexposed area

Exposed area

Figure 4-20

Laser beam exposure

Development block

The second part of the image formation process is the development block, where toner is transferred

onto the electrostatic latent image on the surface of the photosensitive drum to create a visible

image. This MFP uses a contact development method that keeps the developing cylinder in contact

with the drum, pushing the toner against the drum surface for development. The toner is non-

magnetic and consists of resins.

Step 4: Development

In this step, the toner adheres to the electrostatic latent image on the photosensitive drum surface.

The toner (developing material) has an insulating property and is charged with a negative potential

by the friction force with the rotating developing cylinder and the developing blade surface. This

negatively charged toner contacts with the photosensitive drum, after the potential is adjusted to be

uniform. As the area of the drum surface where the laser beam exposed has higher potential than

the developing cylinder, the toner charged with almost the same potential with the developing

cylinder adheres to this area. This phenomenon is called contact development and it visualizes the

electrostatic latent image on the drum surface.

ENWW

Image formation system

169