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HP Color LaserJet Enterprise CM4540 Service Manual - Page 91

Image-stabilization control

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Image-stabilization control NOTE: The product contains a thermal sensor, located within the TCU level detection sensor, which monitors the temperature in the cartridge area and uses this information to make adjustments during CPR control. Environmental changes or deterioration of the photosensitive drums and toner can cause variations in the image density. The image-stabilization control reduces these fluctuations. Table 1-11 Image-stabilization controls Image density control (DMAX) Image halftone control (DHALF) This control corrects variations in image density related to deterioration of the photosensitive drum or the toner. The DC controller adjusts the high-voltage biases to correct the problem under the following conditions: The image-stabilization control calibrates each high-voltage bias to stabilize the fluctuations in image density caused by deterioration of the photosensitive drums or toner or because of environmental changes. The DC controller determines the product's environment based on the surrounding temperature and humidity data from the environment sensor. The DC controller calibrates the biases according to the detected environment and usage condition of the print cartridge to obtain an appropriate image. The DC controller determines an environment sensor failure and notifies the formatter when it detects environmental data from the environment sensor with out of specified value. The DC controller commands the formatter to control the image density under the following conditions ● The temperature of the main thermistor is too low when the product is turned on. ● A print cartridge or the ITB is replaced. ● A specified number of pages have printed. ● After a specific period of the completion of a previous DMAX ● The environment changes for a specified condition after a previous DMAX. The formatter performs this control to calibrate the halftone, based on the halftonedensity measurements, under the following conditions: ● The formatter sends a command. ● DMAX is completed. The DC controller determines an RD sensor failure and notifies the formatter if it detects data from the RD sensor out of a specified range. The DC controller determines a RD sensor failure and notifies the formatter if it detects an out-ofspecified-data value from the RD sensor when the product is turned on or when the color misregistration control starts. ENWW Image-formation system 39

Section	Page
Theory of operation	53
Basic operation	54
Sequence of operation	56
Engine-control system	57
DC controller	58
Solenoids	58
Clutches	59
Switches	59
Sensors	60
Motors	61
Fans	62
High-voltage power supply	64
Low-voltage power supply	66
Overcurrent/overvoltage protection	67
Safety	67
Voltage detection	67
Sleep (powersave) mode	67
Low-voltage power supply failure	68
Fuser control	68
Fuser temperature control	69
Fuser sleeve temperature protection	69
Failure detection	71
Fuser unit identification	71
Fuser unit life detection	72
Laser/scanner system	73
Laser/scanner failure	74
Protective-glass cleaners	74
Image-formation system	76
Image-formation process	78
Step 1: Pre-exposure	79
Step 2: Primary charging	79
Step 3: Laser-beam exposure	80
Step 4: Development	80
Step 5: Primary transfer	81
Step 6: Secondary transfer	81
Step 7: Separation	82
Step 8: Fusing	82
Step 9: ITB cleaning	83
Step 10: Drum cleaning	83
Print cartridge	83
Developing-roller engagement and disengagement	85
Intermediate transfer belt (ITB) unit	86
Primary-transfer-roller engagement and disengagement	87
ITB cleaning	89
Calibration	89
Color-misregistration control	90
Image-stabilization control	91
Pickup, feed, and delivery system	92
Pickup-and-feed unit	96
Cassette pickup	96
Cassette-presence detection	97
Cassette lift operation and cassette paper-presence detection	98
Cassette multiple-feed prevention	99
Multipurpose tray pickup	99
Paper feed	100
Skew-feed prevention	102
Paper detection	102
Feed speed control	103
Fusing and delivery unit	104
Loop control	104
Pressure-roller pressurization control	106
Duplexing unit	107
Duplexing reverse and feed control	107
Duplex print operation	108
Jam detection	110
Optional paper feeders	113
Motor control	115
Paper-feeder pickup and feed operation	116
Paper-size detection and cassette-presence detection	118
Paper-feeder cassette lift operation	119
Paper feeder jam detection	120
Document feeder/scanner assembly	122
Scanner subsystem	122
Document feeder/scanner motor and fan control	123
Legal detection sensor sequence	124
Fan timing sequence	124
Optical assembly operation	125
Image data path	125
Document feeder/scanner paper path and sensors	126
Document feeder pick mechanism	127
3-bin stapling mailbox	128
Motor control	130
Failure detection	131
Delivery operation	132
Staple operation	133
Stapler	138
Output bin 3 lift operation	139
Stacker mode	140
Mailbox/job separator mode	141
Jam Detection	142
Automatic Delivery	143
Removal and replacement	145
Introduction	146
Removal and replacement strategy	146
Electrostatic discharge	147
Required tools	147
Before performing service	148
After performing service	148
Post-service test	149
Print-quality test	149
Parts removal order	150
Customer self repair (CSR) components	152
Control panel	152
Print cartridges	155
Toner-collection unit	156
Formatter PCA	158
Fax card	159
Remove the fax card	159
Hard drive	160
Remove the hard drive	160
Tray	163
Fuser	164
Feed and separation rollers (Trays 2-5)	165
Pickup roller (Tray 1)	166
Reinstalling the pickup roller (Tray 1)	169
Secondary transfer roller	170
Reinstall the transfer roller	171
Intermediate transfer belt (ITB)	172
Standard output bin	175
Output bin bezel	176
Remove the output bin bezel	176
ASY-TRY-F-BASE-SP (document feeder tray extender)	176
ASY-CVR-FE-PICK-SP (pickup roller cover)	177
ASY-ROL-FE-FEED-SP (pickup roller)	177
ASY-HLD-REV-PAD-SP (pickup roller pad) and ASY-SP-REV-SPR (spring)	178
External panels, covers, and doors	179
Identification and location	179
S-CVR-REAR (scanner rear cover)	180
ASY-CVR-F-SP (document feeder front cover)	181
ASY-CVR-F-R-SP (document feeder rear cover)	183
S-CVR-LEFT (scanner left cover)	185
Fan cover	186
Remove the fan cover	187
Lower-left cover	188
Left cover	189
Remove the left cover	189
Right-front cover	190
Remove the right-front cover	190
Reinstall the power button	191
Front-door assembly	192
Remove the front-door assembly	192
Right-rear cover	195
Remove the right-rear cover	195
Rear cover	196
Remove the rear cover	196
Right-door assembly	197
Document feeder	202
ASY-LVR-FE-EMP-SP (paper present flag)	202
Document feeder	203
Remove the document feeder	203
Reinstall the document feeder	204
ASY-CVR-FE-FEED-SP (document feeder jam-access cover)	205
Remove the ASY-CVR-FE-FEED-SP (document feeder jam-access cover)	205
ASY-TRY-SP (tray assembly)	207
Remove the ASY-TRY-SP (tray assembly)	207
ASY-FRM-RE-FEED-SP (internal assembly)	209
Remove ASY-FRM-RE-FEED-SP (internal assembly)	209
ASY-PBA-RELAY-SB (document feeder PCA)	211
Remove the ASY-PBA-RELAY-SB (document feeder PCA)	211
ASM-IF-SP (document feeder cable)	212
Remove the ASM-IF-SP (document feeder cable)	213
ASY-HNG-L-SP (document feeder left hinge)	214
Remove the ASY-HNG-L-SP (document feeder left hinge)	214
ASY-HNG-R-SP (document feeder right hinge)	215
Remove the ASY-HNG-R-SP (document feeder right hinge)	215
ASY-FAN-SP (document feeder fan)	216
Remove the ASY-FAN-SP (document feeder fan)	216
ASY-MOT-FE-SP (motor)	217
Remove the ASY-MOT-FE-SP (motor)	217
ASY-MOT-RE-SP (document feeder motor)	218
Remove the ASY-MOT-RE-SP (motor)	218
ASY-DFSENS-SP (document feeder open sensor)	219
Remove the ASY-DFSENS-SP (document feeder open sensor)	219
ASY-GIDREV-SPR-SP (document feeder jam access plate)	220
Remove the ASY-GIDREV-SPR-SP (document feeder jam access plate)	220
ASY-BASE_SB (base assembly)	221
Remove the ASY-BASE_SB (base assembly)	221
Scanner	222
Scanner filter cover and scanner filter	222
Scanner assembly	223
Remove the scanner	223
Scissor hinge assemblies	226
S-ASSY-CP-ADAPTER (CP adapter assembly)	228
Remove the S-ASSY-CP-ADAPTER (CP adapter assembly)	228
S-PBA-SCB (SCB)	231
Remove the S-PBA-SCB (SCB)	231
S-ASM-USB (USB control panel cable)	233
Remove the S-ASM-USB (USB control panel cable)	233
S-HNG-LIFT-R (scanner release assembly)	235
Remove the S-HNG-LIFT-R (scanner release assembly)	235
S-ASSY-UPPER-UNIT (tub top)	236
Remove the S-ASSY-UPPER-UNIT (tub top)	236
S-PBA-TYUKEI (interconnect board) and S-SNS-EY3A1061–2 (size sensor)	237
Remove the S-PBA-TYUKEI (interconnect board) and S-SNS-EY3A1061–2 (size sensor)	237
S-ASSY-INV (inverter)	240
Remove the S-ASSY-INV (inverter)	240
S-FAN-MFB-30E-05A-006 (inverter fan)	242
Remove the S-FAN-MFB-30E-05A-006 (inverter fan)	242
ASSY-CRG-UNIT-IR4068 (optical assembly)	243
Remove the ASSY-CRG-UNIT-IR4068 (optical assembly)	243
S-ASSY-MOTOR-UNIT (motor assembly)	247
Remove the S-ASSY-MOTOR-UNIT (motor assembly)	247
S-FAN-D06037600G-001 (scanner fan)	249
Remove the S-FAN-D06037600G-001 (scanner fan)	249
Internal assemblies	251
IPTU	251
Remove the IPTU	251
Cassette feed guide	254
Secondary transfer assembly	256
Reinstall the secondary transfer assembly	257
Separation pad (Tray 1)	258
Remove the separation pad (Tray 1)	258
Registration density (RD) sensor assembly	261
Remove the RD sensor assembly	261
Registration assembly	265
Remove the registration assembly	266
Residual-toner-feed motor	270
Remove the residual-toner-feed motor	270
Residual-toner duct and feed assembly	271
Remove the residual-toner duct and feed assembly	271
Cartridge fan and environmental sensor	274
Remove the cartridge fan and environmental sensor	274
Toner-collection sensor and scanner-thermistor assembly	278
Remove the toner-collection sensor and scanner-thermistor assembly	278
Delivery fan	280
Remove the delivery fan	280
Intermediate cover and duplexing gear cover	281
Remove the Intermediate cover and duplexing gear cover	281
Delivery assembly	283
Remove the delivery assembly	283
Reinstall the delivery assembly	286
Duplex-drive assembly	287
Remove the duplex-drive assembly	287
Power-supply fan	288
Remove the power-supply fan	288
Image scanner power supply unit (PSU)	289
Remove the image scanner supply unit (PSU) and fan	290
Interconnect board (ICB)	291
Remove the ICB	291
DC controller PCA only	293
Remove the DC controller PCA only	293
Low-voltage power supply (LVPS)	295
Remove the low-voltage power supply	295
DC controller PCA and tray	300
Remove the DC controller PCA and tray	300
High-voltage power supply lower (HVPS-D)	302
Remove the high-voltage power supply lower	302
Reinstall the high-voltage power supply lower	306
Developing-disengagement motor	307
Remove the developing-disengagement motor	307
Exhaust fan and fan duct	308
Remove the exhaust fan and fan duct	308
Reinstall the exhaust fan and fan duct	310
Pickup motor	311
Remove the pickup motor	311
Lifter-drive assembly	312
Remove the lifter-drive assembly	313
Lifter base assembly	315
Remove the lifter base assembly	315
Reinstall the lifter base assembly	316
Tray-pickup drive assembly	318
Remove the tray-pickup drive assembly	318
Tray-pickup assembly	320
Remove the tray-pickup assembly	321
Laser/scanner assembly (Y/M)	327
Remove the laser/scanner assembly (Y/M)	328
Laser/scanner assembly (C/Bk)	331
Remove the laser/scanner assembly (C/Bk)	332
Reinstall the protective glass cleaner (PGC) actuators	335
High-voltage power supply upper (HVPS-T)	338
Remove the high-voltage power supply upper	338
Reinstall the high-voltage power supply upper	340
Yellow, magenta, cyan, and black drum motors	341
Remove the yellow, magenta, cyan, and black drum motors	341
Fuser motor	342
Remove the fuser motor	343
ITB motor	344
Remove the ITB motor	344
Main-drive assembly	345
Remove the main-drive assembly	346
Reinstall the main-drive assembly	350
Optional paper feeder assemblies (1 x 500-sheet and 3 x 500-sheet)	355
Front door (optional paper feeder)	355
Rear cover (optional paper feeder)	357
Right-front cover (optional paper feeder)	358
Right door (optional paper feeder)	359
Left cover (optional paper feeder)	361
Remove the left cover (optional paper feeder)	361
Right cover (optional paper feeder)	363
Remove the right cover (optional paper feeder)	363
Rear-right cover (optional paper feeder)	364
Remove the rear-right cover (optional paper feeder)	364
Pickup assembly (optional paper feeder)	365
Remove the pickup assembly (optional paper feeder)	365
Lifter assembly (optional paper feeder)	368
Remove the lifter assembly (optional paper feeder)	368
Lifter-drive assembly (optional paper feeder)	369
Remove the lifter-drive assembly (optional paper feeder)	369
Pickup motor assembly (optional paper feeder)	370
Remove the pickup motor (optional paper feeder) assembly	370
Controller PCA (optional paper feeder)	371
Remove the controller PCA (optional paper feeder)	371
Optional 500-sheet paper feeder assembly	373
Rear cover (500-sheet paper feeder)	373
Right-front cover (500-sheet paper feeder)	373
Left cover (500-sheet paper feeder)	374
Remove the left cover (500-sheet paper feeder)	374
Right cover (500-sheet paper feeder)	375
Remove the right cover (500-sheet paper feeder)	375
Front cover (500-sheet paper feeder)	376
Pickup assembly (500-sheet paper feeder)	377
Remove the pickup assembly (500-sheet paper feeder)	377
Lifter assembly (500-sheet paper feeder)	380
Remove the lifter assembly (500-sheet paper feeder)	380
Reinstall the lifter assembly	381
Reinstall the lifter assembly	381
Lifter-drive assembly (500-sheet paper feeder)	382
Remove the lifter-drive assembly (500-sheet paper feeder)	382
Pickup motor assembly (500-sheet paper feeder)	383
Remove the pickup motor (500-sheet paper feeder) assembly	383
Controller PCA (500-sheet paper feeder)	384
Remove the controller PCA (500-sheet paper feeder)	384
Stapling mailbox	385
Stapling mailbox front cover	385
Stapling mailbox rear cover	386
Stapling mailbox door	387
Holder connector	387
Remove the holder connector	388
Top cover	389
Remove the top cover	389
Output bin 3	390
Stapling mailbox PCA	392
Stapler assembly	395
Remove the stapler assembly	395
Stamp solenoid	396
Remove the stamp solenoid	396
Output bin sensor PCA	398
Remove the output bin sensor PCA	398
Stacking panel	400
Remove the stacking panel	400
Jogger assembly	402
Remove the jogger assembly	402
Flapper guide assembly	404
Remove the flapper guide assembly	405
Flapper assembly	406
Remove the flapper assembly	407
MBM output bin assembly	408
Remove the MBM output bin assembly	408
Output bin 3 drive assembly	410
Remove the output bin drive assembly	410
Output bin solenoid	413
Remove the output bin solenoid	413
Solve problems	415
Solve problems checklist	416
Administration Menu Map	418
Troubleshooting process	419
Determine the problem source	419
Pre-troubleshooting checklist	419
Troubleshooting flowchart	421
Power subsystem	422
Power-on checks	422
Power-on troubleshooting overview	422
Control-panel checks	424
Scanning subsystem	425
Tools for troubleshooting	426
Component diagnostics	426
LED diagnostics	426
LED indicators	426
HP Jetdirect LEDs	426
Formatter heartbeat LED	427
Engine diagnostics	427
Defeating interlocks	427
Disable cartridge check	428
Engine-test button	428
Paper-path test	430
Manual sensor test	430
Front-door switch	432
Right-door switch	433
Registration sensor	434
Fuser loop 1 and 2 sensors	435
Fuser output sensor	436
Duplexer refeed sensor	438
IPTU-bin-full sensor	439
Developer alienation sensor	440
Fuser pressure-release sensor	441
ITB alienation sensor	442
IPTU feed sensor	444
Scanner open sensor	444
Tray/Bin manual sensor test	445
Tray 1 paper sensor	447
Tray 2 paper sensor	448
Tray 2 paper surface 1 and 2 sensors	449
Tray 2 paper size switches	450
Tray 3 paper sensor	451
Tray 3 feed sensor	451
Tray 3 paper surface 1 and 2 sensors	452
Tray 3 paper size switches	453
Tray 4 paper sensor	453
Tray 4 feed sensor	454
Tray 4 paper surface 1 and 2 sensors	454
Tray 4 paper size switches	455
Tray 5 paper sensor	455
Tray 5 feed sensor	456
Tray 5 paper surface 1 and 2 sensors	456
Tray 5 paper size switches	457
5V laser and 24V interlock and logic switches (and power switch)	458
Location and testing	458
Defeating	459
New ITB sensor	462
Tray 3, 4, and 5 right door switch	464
Paper-path sensors test	465
Print/stop test	466
Scanner tests	466
Scanner tests	466
Scanner sensor tests	467
Document feeder paper present sensor	468
Document feeder Y (length) sensor	468
Document feeder jam cover sensor	469
Flatbed Y (length) sensor	470
Flatbed cover angle sensor	471
Flatbed cover sensor	472
Document feeder registration sensor	473
Document feeder exit sensor	473
Document feeder read sensor	474
Component tests	474
Control-panel tests	474
Component test (special-mode test)	474
Stapler/stacker	476
Diagrams	478
Block diagrams	478
Plug/jack locations	482
Location of connectors	484
DC controller connector locations	484
Controller PCA (1 x 500-sheet and 3 x 500-sheet optional paper feeders)	486
Stapler/stacker PCA	487
IPTU PCA	488
Locations of major components	489
General timing chart	503
Circuit diagrams	504
Internal print-quality test pages	510
Print-quality-troubleshooting pages	510
Diagnostics page	513
Cleaning page	514
Configuration pages	514
Configuration page	514
HP embedded Jetdirect page	516
Embedded protocol page	517
Finding important information on the configuration pages	518
Color-band test	518
Print-quality troubleshooting tools	519
Repetitive defects ruler	519
Calibrate the product	520
Control panel menus	521
Navigate the Administration menu	521
Interpret control-panel messages	522
Control-panel message types	522
Control-panel messages	522
Clear All Blocked Numbers	522
Clear Event Log	522
Replace Supplies	523
Cleaning Page	523
10.00.70 Printing past very low	523
10.0X.90 Replace <Supply>	524
10.0X.Y0 Supply memory error	524
10.XX.69 <Supply> very low To continue, touch “OK”	525
10.YY.60 <color> cartridge low	525
11.00.YY Internal clock error To continue, touch “OK”	526
13.WX.EE Door open jam	526
13.WX.FF Jam	526
13.WX.YZ Fuser Area Jam	527
13.WX.YZ Fuser wrap jam	528
13.WX.YZ Jam below control panel Clear jam, then touch \	528
13.WX.YZ Jam in left cover	529
13.WX.YZ Jam in lower bin area	530
13.WX.YZ Jam in top cover area	530
13.WX.YZ Jam in Tray 1 Clear jam, then touch \	530
13.WX.YZ Jam in Tray <X>	530
13.WX.YZ Jam inside lower right door	531
13.WX.YZ Jam inside output accessory bridge	531
13.WX.YZ Jam inside right door	532
13.WX.YZ Jams inside lower right door	532
13.WX.YZ Jams inside right door	533
13.WX.YZ Staple jam inside left cover	534
20.00.00 Insufficient memory: <Device> To continue, touch “OK”	534
21.00.00 Page Too Complex To continue, touch “OK”	535
30.01.YY Scanner Failure	535
30.01.YY Scanner Failure	535
30.01.YY Scanner Failure	535
30.01.YY Scanner Failure	536
30.01.YY Scanner Failure	536
30.01.YY Scanner Failure	536
30.01.YY Scanner Failure	537
30.01.YY Scanner Failure	537
30.01.YY Scanner Failure	537
30.01.YY Scanner Failure	537
30.01.YY Scanner Failure	538
30.01.YY Scanner Failure	538
30.01.YY Scanner Failure	538
30.01.YY Scanner Failure	539
30.01.YY Scanner Failure	539

Match case Limit results 1 per page

Image-stabilization control

NOTE:

The product contains a thermal sensor, located within the TCU level detection sensor, which

monitors the temperature in the cartridge area and uses this information to make adjustments during

CPR control.

Environmental changes or deterioration of the photosensitive drums and toner can cause variations in

the image density. The image-stabilization control reduces these fluctuations.

Table 1-11

Image-stabilization controls

Image density control (DMAX)

This control corrects variations in image density related to deterioration of the

photosensitive drum or the toner. The DC controller adjusts the high-voltage biases

to correct the problem under the following conditions:

The image-stabilization control calibrates each high-voltage bias to stabilize the

fluctuations in image density caused by deterioration of the photosensitive drums or

toner or because of environmental changes. The DC controller determines the

product's environment based on the surrounding temperature and humidity data

from the environment sensor. The DC controller calibrates the biases according to

the detected environment and usage condition of the print cartridge to obtain an

appropriate image. The DC controller determines an environment sensor failure and

notifies the formatter when it detects environmental data from the environment

sensor with out of specified value. The DC controller commands the formatter to

control the image density under the following conditions

●

The temperature of the main thermistor is too low when the product is turned

on.

●

A print cartridge or the ITB is replaced.

●

A specified number of pages have printed.

●

After a specific period of the completion of a previous DMAX

●

The environment changes for a specified condition after a previous DMAX.

Image halftone control (DHALF)

The formatter performs this control to calibrate the halftone, based on the halftone-

density measurements, under the following conditions:

●

The formatter sends a command.

●

DMAX is completed.

The DC controller determines an RD sensor failure and notifies the formatter if it

detects data from the RD sensor out of a specified range.

The DC controller determines a RD sensor failure and notifies the formatter if it detects an out-of-

specified-data value from the RD sensor when the product is turned on or when the color misregistration

control starts.

ENWW

Image-formation system