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HP 4600dn Service Manual - Page 99

Heater temperature control, SUBTH1 drops.

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Heater temperature control The heater temperature control detects the surface temperature of the fuser sleeve and controls the current flowing to the induction heating coil. The heater temperature control circuit is shown in Figure 5-6. Figure 5-6 Heater temperature control circuit The two thermistors that are attached to the fuser sleeve (TH1 and TH2) detect the surface temperature of the fuser sleeve. The main thermistor (TH1) controls the fuser temperature, and the sub thermistor (TH2) detects overheating at the end of the fuser sleeve. When the surface temperature of the fuser sleeve increases, resistance of the two thermistors is reduced, and the voltage of the main thermistor detection signal (MAINTH1) and the sub thermistor detection signal (SUBTH1) drops. The CPU (IC1012) on the DC controller monitors the voltage of the MAINTH1 and SUBTH1 signals. The CPU sends the fuser temperature control signal (TMPCON) according to the voltage level. The CPU sends the amperage control signal (PRANGE) to control the amperage of the fuser sleeve. C9660-90901 Chapter 5 Theory of operation 97

Section	Page
Contents	7
List of figures	13
List of tables	17
Printer description	19
Printer features	20
Identification	23
Model and serial numbers	23
Power and regulatory information	24
Site requirements	25
Space requirements	25
Electrical specifications	26
Environmental specifications	26
Supply storage requirements	27
Printer specifications	27
Printer assemblies	28
Media requirements	30
Selecting print media	30
Media specifications	30
Supported media weights and sizes	31
Media to avoid	33
Media that may cause damage to the printer	33
Printing on special media	33
Weight equivalence table	37
Environmental Product Stewardship Program	38
Protecting the environment	38
Regulatory statements	40
FCC Regulations	40
Safety information	41
Laser safety statement	41
Material Safety Data Sheet	41
Toner safety	41
Canadian DOC regulations	41
EMI statement (Korea)	41
VCCI statement (Japan)	42
Laser statement for Finland	43
Declaration of Conformity	44
Service approach	45
Service approach	46
Parts and supplies	47
Ordering parts	47
Ordering supplies	47
Exchange program	48
Supplies	48
World Wide Web	48
HP Service Parts Information Compact Disc	48
HP Support Assistant Compact Disc	48
Customer care reseller sales and service support center	48
Ordering related documentation and software	49
Warranty statement	50
Hewlett-Packard warranty statement	50
Limited warranty for print cartridge life	51
Transfer unit and fuser warranty	51
HP maintenance agreements	52
On-site service agreements	52
Installation and configuration	53
Unpack the printer	54
Unpacking the printer	55
Installation	58
Installing the media tray	58
Connecting power	59
Installing the print cartridges	59
Installing a new overlay (optional)	61
Testing the printer operation	61
Using PowerSave	62
Connecting to a computer	63
Parallel connections	63
Network connections	64
Enhanced I/O (EIO) configuration	66
HP Jetdirect print servers	66
Available enhanced I/O interfaces	66
NetWare networks	66
Windows and Windows NT networks	67
AppleTalk networks	67
LocalTalk configuration	67
LocalTalk network configuration	67
UNIX/Linux networks	67
Printer drivers	68
Available drivers	68
Additional drivers	69
Network configuration	70
Configuring the printer for the network	70
Configuring Novell NetWare frame type parameters	70
Setting network security on the printer	71
Locking the control panel	71
Using an ASCII PJL escape sequence to set network security	72
Printer maintenance	73
Cleaning the printer and accessories	74
Cleaning spilled toner	74
Approximate replacement intervals for supply items	75
ETB life under different circumstances	76
Locating supplies	77
Replacing supply items	78
Changing print cartridges	78
Replacing the transfer unit	81
Replacing the fuser	84
Printer memory	86
Installing memory and font DIMMs	87
Installing an HP Jetdirect print server card	90
Theory of operation	91
Basic operation	92
Operation sequence	93
Engine control system	94
DC controller circuit	95
Motors and fans	96
Fuser power supply circuit	98
Heater temperature control	99
High-voltage power supply	100
Low-voltage power supply	101
Formatter system	102
PowerSave	103
Input/Output	103
Printer memory	104
DIMM slots	104
PJL overview	104
PML	105
Control panel	105
Laser/scanner system	106
Scanner motor control	107
Image formation system	108
Image formation process	109
Print cartridges	110
Toner level detection	112
Electrostatic transfer/transport belt (ETB) unit	114
Electrostatic latent image formation block	115
Development block	117
Transfer block	118
Fusing block	120
Cleaning block	120
Calibration and cleaning	121
Color plane registration calibration	124
Drum phase calibration	124
Image stabilization control	125
Pickup/feed system	127
Pickup/feed unit	130
Fuser/delivery unit	134
Duplex feed unit	135
500-sheet paper feeder	136
Pickup and feed operations	137
Removal and replacement	139
Introduction	141
Removal and replacement strategy	141
Repair notices	141
Caution regarding electrostatic discharge (ESD)	141
Required tools	142
Types of screws	143
Supplies	144
Print cartridges and ETB	145
Covers and external components	146
Rear cover	146
Top cover	147
Rear top cover	148
Left cover	150
Right cover	152
Multi-purpose tray (Tray 1)	153
Front cover	154
Control panel	155
Internal components	157
DC controller shield	157
Internal components (front)	158
Paper pickup unit	158
Paper pickup sensor PCB	159
Cassette (Tray 2) paper pickup rollers	160
Paper pickup drive unit	161
Multi-purpose tray pickup roller and separation pad	162
Solenoids	163
Color registration detection unit	164
Internal components (left side)	166
Drum drive units	166
Memory tag antenna PCBs	172
Developing disengaging motor assembly	173
DC controller PCB	174
Memory controller PCB	175
Cassette paper size detection switch	176
Internal components (rear)	177
Formatter	177
Low-voltage power supply	178
Formatter case	180
Laser/scanner units	182
Internal components (right side)	187
High-voltage power supply PCB	187
Toner level detection PCB	189
High-voltage contact blocks	190
Door switch	191
Internal components (top)	192
Fuser power supply PCB	192
Fuser drive unit	194
Fuser inlet paper sensor	196
Fuser delivery sensor	197
Output bin full sensor	198
Cartridge fan	199
Formatter fan	200
Optional 500-sheet paper feeder	201
Paper feeder top cover plate	201
Paper feeder drive unit	202
Paper feeder pickup rollers	203
Paper feeder PCB	204
Troubleshooting	205
Introduction	207
Troubleshooting process	208
Pre-troubleshooting checklist	209
Troubleshooting flowchart	210
Troubleshooting power-on	212
Printer error troubleshooting	213
Status messages	213
Warning messages	213
Error messages	213
Critical error messages	213
Alphabetical printer messages	214
Numerical printer messages	225
Paper path troubleshooting	236
Jams	236
Jam locations	236
Jam locations by error message	237
Paper jam recovery	238
Avoiding paper jams	239
Persistent jams	240
Paper transport troubleshooting	246
Multiple pages are fed	246
Paper is wrinkled or folded	246
Paper is skewed	247
Image formation troubleshooting	248
Print quality problems associated with media	248
Overhead transparency defects	249
Print quality problems associated with the environment	249
Print quality problems associated with jams	249
Print quality troubleshooting pages	249
Understanding color variations	250
Color selection process	250
Matching colors	251
Using color	251
Color options	252
Adjusting color balance	254
Image defects	255
Repetitive defects troubleshooting	262
Interface troubleshooting	265
Communications checks	265
EIO troubleshooting	265
AUTOEXEC.BAT standard configurations	266
Printer Job Language (PJL) commands	266
Control panel troubleshooting	269
Printing a menu map	269
Information menu	270
Paper handling menu	270
Configure device menu	271
Diagnostics menu	275
Service menu	276
Tools for troubleshooting	277
Embedded Web server	277
To access the embedded Web server	277
Printer Status and Alerts software	280
Printer configuration page	281
Supplies status page	282
Usage page	283
Event log	284
Diagnostics	285
Diagnostics flowchart	285
Engine diagnostics	287
Individual diagnostic tests	289
Test pages	294
Engine test page	294
Formatter test page	294
Engine resets	295
Cold reset	295
NVRAM initialization	295
Hard disk initialization	296
Calibration bypass	296
Calibrate Now	296
Service menu	297
Accessing the Service menu	297
Diagrams	299
Main parts	299
Switches	300
Sensors	301
Solenoids	303
Motors and fans	304
PCBs	305
DC controller PCB	306
Connectors	307
500-sheet paper feeder connectors	308
General circuit diagram	309
500-sheet paper feeder circuit diagram	310
Parts and diagrams	311
Introduction	312
Ordering parts	313
Supplies and accessories	313
Common fasteners	316
Illustrations and parts lists	317
Alphabetical parts list	344
Numerical parts list	350

Match case Limit results 1 per page

C9660-90901

Chapter 5 Theory of operation

Heater temperature control

The heater temperature control detects the surface temperature of the fuser sleeve and controls the

current flowing to the induction heating coil. The heater temperature control circuit is shown in

Figure 5-6.

Figure

5-6

Heater temperature control circuit

The two thermistors that are attached to the fuser sleeve (TH1 and TH2) detect the surface

temperature of the fuser sleeve. The main thermistor (TH1) controls the fuser temperature, and the

sub thermistor (TH2) detects overheating at the end of the fuser sleeve. When the surface

temperature of the fuser sleeve increases, resistance of the two thermistors is reduced, and the

voltage of the main thermistor detection signal (MAINTH1) and the sub thermistor detection signal

(SUBTH1) drops.

The CPU (IC1012) on the DC controller monitors the voltage of the MAINTH1 and SUBTH1 signals.

The CPU sends the fuser temperature control signal (TMPCON) according to the voltage level.

The CPU sends the amperage control signal (PRANGE) to control the amperage of the fuser sleeve.