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HP 4300 Service Manual - Page 94

Low-voltage circuit, Low-voltage circuit block diagram

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The developing voltage (bias) causes the toner to adhere to the electrostatic image that the laser/scanner assembly created on the photosensitive drum. There are two types of developing biases. The developing dc negative bias and the developing ac bias. Both biases are generated by the high-voltage circuit on the power supply. These biases are superimposed on one another and then applied to the primary charging roller which will transfer the biases to the drum. The biased developing cylinder picks up toner particles and deposits them onto the electrostatic image on the photosensitive drum. The image is now visible on the drum. The transfer voltage (bias) allows the toner image on the photosensitive drum to transfer to the media. There are two types of developing biases. The transfer dc positive bias and the dc negative bias. Both biases are generated by the high-voltage circuit on the power supply. Transfer dc positive bias is applied to the transfer roller during the toner transfer process. Transfer dc positive bias is applied to the transfer roller during the transfer roller cleaning process. The dc positive bias attracts the toner to the media (this transfers the toner image on the photosensitive drum to the media). The dc negative bias is used to clean residual toner off of the transfer roller. The fuser voltage (bias) prevents toner on the media from sticking to the fuser's pressure roller. For the HP LaserJet 4200 there is one type of fuser bias. A dc positive bias is generated by the sub high-voltage circuit on the power supply. The dc positive bias is applied to the pressure roller in the fuser. For the HP LaserJet 4300 there are two types of fuser biases. The fuser dc positive bias and a dc negative bias. Both biases are generated by the sub high-voltage circuit on the power supply. The dc positive bias is applied to the pressure roller in the fuser. The dc negative bias is applied to the fixing film in the fuser. Low-voltage circuit The low-voltage circuit converts the ac power from the power source (the wall receptacle the printer's power cord is plugged into) into the direct current voltage (vdc) used by printer components (like the motors and fans). The ac voltage is converted into +24 vdc, +5 vdc, and +3.3 vdc. The +24 vdc voltage is supplied to printer components like the main motor, laser/ scanner assembly motor, solenoids and clutches. The +5 vdc voltage is supplied to the laser/ scanner assembly. The +3.3 vdc is supplied to the sensors and the DC controller PCA. Figure 11. Low-voltage circuit block diagram 74 Theory of operation Q2431-90912

Section	Page
Table of contents	5
List of figures	11
List of tables	17
Printer description	21
Printer configurations	23
Model and serial numbers	24
Site requirements	25
Printer specifications	25
Physical dimensions	26
Printer weights (without print cartridge)	27
Environmental specifications	27
Paper specifications	29
Supported sizes and weights of media	30
Supported types of media	34
Guidelines for using paper	34
Paper weight equivalence table	35
Labels	36
Overhead transparencies	36
Envelopes	37
Envelope construction	37
Envelopes with double-side-seams	37
Envelopes with adhesive strips or flaps	37
Envelope margins	38
Envelope storage	38
Card stock and heavy paper	38
Card stock construction	38
Card stock guidelines	38
Types of print media to avoid	39
Safety information	40
Print cartridge and toner safety	40
Handling and storage	40
First aid measures	40
Clothing contact	40
Additional information	40
Laser safety	40
Laser safety statement (U.S.)	40
EMI statement (Korea)	41
VCCI statement (Japan)	41
Laser statement (Finland)	42
Regulatory information	43
FCC regulations	43
Environmental product stewardship program	44
Protecting the environment	44
Energy consumption	44
Toner consumption	44
Paper use	44
Plastics	44
HP LaserJet printing supplies	44
Paper	44
Material restrictions	45
For more information	45
HPPrinting Supplies Returns and Recycling program information	45
U.S. returns	45
NonU.S. returns	45
Declarations of Conformity	46
Declaration of Conformity	46
Canadian DOC regulations	46
Service approach	47
Service approach	48
Parts and supplies	48
Ordering information	48
Related documentation and software	48
Support	48
HP-authorized resellers and support	49
HP service agreements	49
HP PartnerCare	49
Worldwide service and support offices	50
Print-cartridge information	51
Refilled print cartridges	51
Recycling print cartridges	51
Returns	51
HewlettPackard limited warranty statement	52
Limited warranty for toner cartridge life	53
Printer operation	55
Using the control panel	56
Control-panel layout	56
Control-panel lights	56
Control-panel buttons	57
Using the printer Help system	57
Settings and defaults	58
Setting the control-panel display language	58
Control-panel menus	59
Overview	59
Printing and changing control-panel menus	59
To print a control-panel menu map	59
To change a control-panel setting	60
Retrieve Job menu	61
Information menu	61
Paper Handling menu	62
Configure Device menu	64
Printing submenu	64
PCL sub-submenu (a submenu in the printing submenu)	65
Print Quality submenu	66
System Setup submenu	69
Stapler/stacker submenu	71
I/O submenu	72
Printer maintenance	73
Cleaning the printer and accessories	74
Cleaning the fuser	75
Running the cleaning page manually	76
To run the cleaning page manually	76
Running the cleaning page automatically	77
To run the cleaning page automatically	77
Cleaning spilled toner	77
Performing preventative maintenance	78
Resetting the maintenance-kit counter	78
Expected life of components	79
Maintaining the stapler unit	80
Removing and replacing the stapler unit	80
To remove and replace the stapler unit	80
Loading staples	82
To load staples	82
Downloading a remote firmware update	83
Theory of operation	85
Introduction	87
Basic operation of the printer	87
Printer operating sequence	87
Control system overview	88
Pickup and feed system overview	88
Laser/scanner system overview	88
Image formation system overview	88
General descriptions	89
DC controller PCA	89
Motor and fan control	90
Power supply	91
Fuser-control circuit	91
Fuser over-temperature protection	92
High-voltage circuit	93
Low-voltage circuit	94
Overcurrent/overvoltage protection	95
Toner detection	95
Cartridge detection	95
Cartridge memory	95
Laser/scanner assembly	96
Laser/scanner control	97
Paper pickup system	98
Paper pickup and feed block	99
Printing from tray 1	100
Printing from tray 2	102
Tray 2, 500-, 1,500-sheet feeder media size detection	103
Lifter-driver operation	104
Multiple feed prevention	104
Media skew prevention	105
Fixing/delivery block	106
Printer jam detection	107
Printer pickup delay jam from tray 1	107
Printer pickup delay jam from tray 2	107
Printer pickup stationary jam	107
Printer delivery wrap jam when feeding regular media	108
Printer delivery wrap jam when feeding non-regular media	108
Printer delivery delay jam	108
Printer door open jam	109
Printer residual media jam	109
Printing from the 500-sheet feeder	110
500-sheet feeder pickup and feeding	110
Printing from the 1,500-sheet feeder	112
1,500-sheet feeder pickup and feeding	112
1,500-sheet feeder lifting mechanism	114
Envelope feeder	115
Envelope feeder pickup and feeding	116
Envelope feeder jam detection	117
Envelope feeder pickup delay jam	117
Envelope feeder pickup stationary jam	117
Duplexer	118
Reversing and duplexer pickup	119
Duplexer jam detection	120
Stacker and stapler/stacker	121
Stacker	123
Stacker feed and delivery	124
Stacker jam detection	125
Stacker feed jam	125
Stacker feed stationary jam	125
Stacker residual media jam	125
Stapler/stacker	126
Stapler/stacker feed and delivery	127
Staple mode feed and delivery	129
Stapler unit	133
Stapler unit operation	134
Staple level detection	136
Stack mode feed and delivery	136
Stapler/stacker jam detection	137
Stapler/stacker feed jam	137
Stapler/stacker feed stationary jam	137
Stapler/stacker delivery jam	137
Stapler/stacker residual media jam	137
Imageformation system	138
Electrostatic latentimage formation	140
Primary charging	140
Writing the image	141
Developing the image	142
Transferring the image	143
Fusing the image	144
Cleaning the transfer charging roller and photosensitive drum	145
Print cartridge memory chip	146
Formatter system	147
PowerSave	147
Resolution Enhancement technology	147
EconoMode	148
Input/output	148
Parallel interface	148
Expanded I/O	148
Flash	148
Hard-disk accessory	148
CPU	148
Printer memory	149
Read-only memory	149
Random-access memory	149
DIMM slots	149
Firmware DIMM	149
Nonvolatile memory	149
Memory Enhancement technology	149
PJL overview	150
PML	150
Control panel	150
Removing and replacing parts	151
Removal and replacement strategy	153
Required tools	153
Before performing service	153
After completing service	153
Screws used in the printer	154
Parts-removal tree	155
Printer input tray, and cabinet wheel locks	156
User-replaceable parts	157
Print cartridge	157
Transfer roller	158
Tray 1 pickup roller	159
Tray1 separation pad	160
Tray2 feed rollers	161
Covers, tray1, and the rear output bin	163
Accessory covers and the tray2 extension door	163
Formatter cover	165
Top cover	166
Rightside cover	169
Leftside cover	171
Tray1	172
Rear output bin	175
Controlpanel display	176
Controlpanel overlay	176
Controlpanel assembly	177
Internal components	180
Firmware DIMM	180
Formatter assembly	181
Fuser	182
Output delivery assembly	183
Duplexing pendulum assembly	185
Tray2 mediasize sensor	187
Main cooling fan (left side)	188
Cooling fan (right side; HPLaserJet4300 series printer only)	190
Laser/scanner assembly	193
Print-cartridge motor (HPLaserJet4300 series printer only)	195
Main motor	197
Tray2 lifter-drive assembly	199
DCcontrollerPCA	201
Paperpickup assembly,	203
Main drive assembly	206
Power supply	208
Paper-feed belt assembly	211
Tray1 paperpickup assembly	212
Paper feed assembly	215
Registration assembly	218
Transfer assembly	220
Accessories	224
500sheet feeder assembly	224
500sheet feed rollers	224
500-sheet feeder right-side cover	224
500sheet feeder controlPCA	227
500sheet feeder mediasize sensor	228
500sheet feeder lifterdrive assembly	229
500sheet feeder paperpickup drive assembly	230
1,500sheet feeder assembly	234
1,500sheet feeder feed rollers	234
1,500sheet feeder separation roller	234
1,500sheet feeder door	235
1,500sheet feeder rear cover	237
1,500sheet feeder rightside cover	238
1,500sheet feeder controlPCA	240
1,500sheet feeder mediasize sensor	241
1,500sheet feeder lifterdrive assembly	242
1,500sheet feeder paperpickup drive assembly	245
Troubleshooting	247
Introduction	250
Troubleshooting process	251
Initial troubleshooting checklist	252
Troubleshooting flowchart	254
Power-on checks	256
Overview	256
Troubleshooting tools	259
Information pages	259
Menu map	260
Configuration page	261
Supplies status page	262
EmbeddedWebserver	263
Gaining access to the embeddedWebserver	263
Information tab	264
Settings tab	264
Networking tab	264
Other links	265
Printer Status and Alerts software	265
To select status messages	266
To view status messages and information	266
Controlpanel menus	267
Using controlpanel menus	267
Resets submenu	267
Diagnostics menu	268
Service menu (service PIN codes)	269
Service ID	270
Restoring the Service ID	270
Converting the ServiceID to an actual date	270
Printer resets and poweron modes	271
Cold reset	271
To perform a cold reset	271
NVRAM initialization	271
To initialize NVRAM	271
Harddisk initialization	272
To initialize the hard disk	272
Poweron bypass	272
Skip disk load	272
Self test	273
Test pages	274
Engine test page	274
Formatter test page	274
Interface troubleshooting	275
Communications checks	275
Computer direct connect (parallel) test	275
EIO troubleshooting	275
Jetdirect page	276
Displaymessage troubleshooting	277
Status messages	277
Warning messages	277
Error messages	277
Criticalerror messages	277
Alphabetical printer messages	278
Numerical printer messages	294
Paperpath troubleshooting	315
Overview	315
Paperjam recovery	316
To disable the paperjam recovery	316
Avoiding paper jams	317
Persistent jams	318
Basic troubleshooting for persistent jams	318
Data collection	318
General paperpath troubleshooting	319
Paperpath checklist	319
Paperpath test	320
To perform a paper test	320
Jams in tray 1	321
Jams in tray2	321
Jams in tray3 and/or tray4	322
Jams in the paper path	323
Jams in the duplex path	323
Media transport problems	324
Multiple pages feed	324
Paper is wrinkled or folded	324
Paper is skewed	325
Image-formation troubleshooting	326
Print quality problems associated with media	326
Overhead transparency defects	327
Print quality problems associated with the environment	327
Print quality problems associated with jams	327
Image defects	328
Overview	328
Image quality	328
Check the print cartridge	329
EconoMode	329
Half selftest functional check	330
Drum rotation functional check	330
Image defect tables	331
Repetitive defects troubleshooting	345
Troubleshooting the stacker and the stapler/stacker	346
Overview	346
Initial checks	346
Jam errors	347
Stacker and stapler/stacker paper path	347
Stacker paper path test	347
Stapler/stacker paper path test	348
Paper transport errors	350
Malfunction errors	350
Component errors	351
Printer component locations	352
Main printer parts	352
Printer switches and sensors	356
Printer motors and fans	357
Printer PCAs	358
Accessory component locations	359
500sheet feeder main parts	359
500sheet feeder switches, sensors, solenoids, andPCAs	360
1,500sheet feeder main parts	361
1,500sheet feeder switches, sensors, solenoids, andPCAs	363
Stapler/stacker stapler assembly	364
Stacker and stapler/stacker switches and sensors	365
Stacker and stapler/stacker motors and solenoids	366
Stacker and stapler/stacker PCAs	367
Printer and accessory wiring diagrams	368
DC controller block diagram	376
General timing diagrams	377
Parts and diagrams	381
Ordering parts, supplies, and getting support	382
Ordering information	382
Related documentation and software	382
Support	382
HP-authorized resellers and support	383
HP service agreements	383
HP PartnerCare	383
Accessories and supplies	384
How to use the parts lists and diagrams	387
Parts diagrams and lists	388
Alphabetical parts list	425
Numerical parts list	429

Match case Limit results 1 per page

Theory of operation

Q2431-90912

The developing voltage (bias) causes the toner to adhere to the electrostatic image that the

laser/scanner assembly created on the photosensitive drum. There are two types of developing

biases. The developing dc negative bias and the developing ac bias. Both biases are generated

by the high-voltage circuit on the power supply. These biases are superimposed on one another

and then applied to the primary charging roller which will transfer the biases to the drum. The

biased developing cylinder picks up toner particles and deposits them onto the electrostatic

image on the photosensitive drum. The image is now visible on the drum.

The transfer voltage (bias) allows the toner image on the photosensitive drum to transfer to the

media. There are two types of developing biases. The transfer dc positive bias and the dc

negative bias. Both biases are generated by the high-voltage circuit on the power supply.

Transfer dc positive bias is applied to the transfer roller during the toner transfer process.

Transfer dc positive bias is applied to the transfer roller during the transfer roller cleaning

process. The dc positive bias attracts the toner to the media (this transfers the toner image on

the photosensitive drum to the media). The dc negative bias is used to clean residual toner off of

the transfer roller.

The fuser voltage (bias) prevents toner on the media from sticking to the fuser’s pressure roller.

For the HP LaserJet 4200 there is one type of fuser bias. A dc positive bias is generated by the

sub high-voltage circuit on the power supply. The dc positive bias is applied to the pressure roller

in the fuser.

For the HP LaserJet 4300 there are two types of fuser biases. The fuser dc positive bias and a

dc negative bias. Both biases are generated by the sub high-voltage circuit on the power supply.

The dc positive bias is applied to the pressure roller in the fuser. The dc negative bias is applied

to the fixing film in the fuser.

Low-voltage circuit

The low-voltage circuit converts the ac power from the power source (the wall receptacle the

printer’s power cord is plugged into) into the direct current voltage (vdc) used by printer

components (like the motors and fans). The ac voltage is converted into +24 vdc, +5 vdc, and

+3.3 vdc. The +24 vdc voltage is supplied to printer components like the main motor, laser/

scanner assembly motor, solenoids and clutches. The +5 vdc voltage is supplied to the laser/

scanner assembly. The +3.3 vdc is supplied to the sensors and the DC controller PCA.

Figure 11.

Low-voltage circuit block diagram