LASERJET PRO 200 COLOR
Troubleshooting Manual
M251n M251nw
HP LaserJet Pro 200 color M251 Series
Printer
Troubleshooting Manual
Copyright and License
Trademark Credits
© 2012 Copyright Hewlett-Packard
Development Company, L.P.
Reproduction, adaptation, or translation
without prior written permission is
prohibited, except as allowed under the
copyright laws.
The information contained herein is subject
to change without notice.
The only warranties for HP products and
services are set forth in the express warranty
statements accompanying such products and
services. Nothing herein should be
construed as constituting an additional
warranty. HP shall not be liable for technical
or editorial errors or omissions contained
herein.
Part number: CF146-90968
Edition 1, 9/2012
Microsoft®, Windows®, Windows® XP,
and Windows Vista® are U.S. registered
trademarks of Microsoft Corporation.
ENERGY STAR and the ENERGY STAR mark
are registered U.S. marks.
Conventions used in this guide
TIP: Tips provide helpful hints or shortcuts.
NOTE: Notes provide important information to explain a concept or to complete a task.
CAUTION: Cautions indicate procedures that you should follow to avoid losing data or damaging
the product.
WARNING! Warnings alert you to specific procedures that you should follow to avoid personal
injury, catastrophic loss of data, or extensive damage to the product.
ENWW iii
Table of contents
1 Theory of operation .......................................................................................................... 1
Basic operation ........................................................................................................................ 2
Major product systems ............................................................................................... 2
Product components .................................................................................................. 3
Sequence of operation ............................................................................................... 4
Engine control system ............................................................................................................... 5
DC controller ............................................................................................................ 6
Low-voltage power supply .......................................................................................... 7
High-voltage power supply ......................................................................................... 8
Laser/scanner system ............................................................................................................... 9
Laser failure detection ................................................................................................ 9
Image-formation system ........................................................................................................... 10
Image-formation process .......................................................................................... 10
Latent-image formation stage .................................................................................... 11
Step 1: primary charging .......................................................................... 12
Step 2: laser-beam exposure ..................................................................... 12
Developing stage .................................................................................................... 12
Step 3: development ................................................................................. 13
Transfer stage ......................................................................................................... 14
Step 4: primary transfer ............................................................................ 14
Step 5: secondary transfer ......................................................................... 14
Step 6: separation from the ITB .................................................................. 15
Fusing stage ........................................................................................................... 15
Step 7: fusing .......................................................................................... 15
ITB cleaning stage ................................................................................................... 16
Step 8: ITB cleaning ................................................................................. 16
Drum cleaning stage ................................................................................................ 17
Step 9: drum cleaning .............................................................................. 17
Pickup-and-feed system ........................................................................................................... 18
Jam detection ......................................................................................................... 19
USB flash drive ...................................................................................................................... 20
ENWW v
2 Solve problems ............................................................................................................... 21
Solve problems checklist ......................................................................................................... 22
Menu map ............................................................................................................................ 24
Print a menu map (LCD control panel) ........................................................................ 24
Print a menu map (touchscreen control panel) ............................................................. 24
Troubleshooting process .......................................................................................................... 25
Pre-troubleshooting checklist ..................................................................................... 25
Power-on checks ..................................................................................................... 27
Tools for troubleshooting ......................................................................................................... 28
Component diagnostics ............................................................................................ 28
LED diagnostics ........................................................................................ 28
Network LEDs ........................................................................... 28
Control panel LEDs .................................................................... 29
Control-panel diagnostics .......................................................................... 30
Engine diagnostics ................................................................................... 30
Engine test ................................................................................ 30
Diagrams ............................................................................................................... 31
Plug/jack locations ................................................................................... 31
DC controller PCA .................................................................................... 32
Locations of major components .................................................................. 34
General timing chart ................................................................................. 36
General circuit diagram ............................................................................ 37
Internal print-quality test pages .................................................................................. 38
Interpret the Print Quality Page ................................................................... 38
Print a cleaning page ............................................................................... 38
Print a cleaning page (LCD control panel) .................................... 39
Print a cleaning page (touchscreen control panel) .......................... 39
Configuration page .................................................................................. 39
Print a configuration page (LCD control panel) .............................. 39
Print a configuration page (touchscreen control panel) ................... 40
Print-quality troubleshooting tools .............................................................................. 41
Repetitive image defects ............................................................................ 41
Calibrate the product to align the colors ...................................................... 41
Control-panel menus ................................................................................................ 42
Setup Menu ............................................................................................. 42
HP Web Services ...................................................................... 42
Reports menu ............................................................................ 43
Self Diagnostics menu ................................................................ 44
System Setup menu .................................................................... 45
Service menu ............................................................................ 48
Network Setup menu ................................................................. 50
vi ENWW
Quick Forms menu .................................................................... 51
Function specific menus ............................................................................. 52
Apps ....................................................................................... 52
USB Flash Drive ........................................................................ 52
Interpret control panel messages ............................................................................... 53
Control panel message types ..................................................................... 53
Control panel messages ............................................................................ 53
10.X00Y Supply Error ................................................................ 53
49 Error, Turn off then on ........................................................... 54
50.x Fuser Error ........................................................................ 54
51.XX Error .............................................................................. 54
54.XX Error .............................................................................. 54
55.X Error ................................................................................ 55
57 Fan Error, Turn off then on ..................................................... 55
59.X Error ................................................................................ 55
79 Error Turn off then on ............................................................ 56
Black Cartridge Low .................................................................. 56
Black in wrong position .............................................................. 56
Black Very Low ......................................................................... 56
Cleaning .................................................................................. 57
Cyan Cartridge Low .................................................................. 57
Cyan in wrong position .............................................................. 57
Cyan Very Low ......................................................................... 57
Device error, press OK .............................................................. 58
Door open ................................................................................ 58
Genuine HP supply installed ....................................................... 58
Incompatible <color> ................................................................. 58
Incorrect supplies ...................................................................... 58
Install <color> cartridge ............................................................. 59
Invalid driver Press [OK] ............................................................ 59
Jam in Tray 1, Clear jam and then press OK ................................ 59
Load tray 1 Press [OK] for available media .................................. 59
Load Tray 1 <TYPE> <SIZE>, Press OK to use available media ....... 59
Load Tray 1, <PLAIN> <SIZE> / Cleaning mode, OK to start ......... 59
Magenta Cartridge Low ............................................................. 60
Magenta in wrong position ........................................................ 60
Magenta Very Low .................................................................... 60
Manual Duplex Load Tray 1, Press OK ........................................ 60
Memory is low. Press OK. .......................................................... 61
Misprint, Press OK ..................................................................... 61
Print failure, press OK. If error repeats, turn off then on. ................. 61
ENWW vii
Rear door open ......................................................................... 61
Remove shipping lock from <color> cartridge ............................... 62
Remove shipping locks from cartridges ........................................ 62
Replace <color> ....................................................................... 62
Supplies low ............................................................................. 62
Unexpected size in tray 1 Load <size> Press [OK] ........................ 62
Unsupported <color> Press [OK] to continue .............................. 0
Used <color> in use ............................................................... 0
Used <color> installed, to accept press OK ............................... 0
Used supplies in use ............................................................... 0
Yellow Cartridge Low ............................................................. 0
Yellow in wrong position ......................................................... 0
Yellow Very Low .................................................................... 0
Event-log messages ............................................................................................... 0
Clear jams ......................................................................................................................... 0
Jam locations ....................................................................................................... 0
Clear jams in the paper input tray .......................................................................... 0
Clear jams from the output bin ............................................................................... 0
Clear jams from the rear door ................................................................................ 0
Solve paper-handling problems ............................................................................................. 0
The product picks up multiple sheets of paper .......................................................... 0
The product does not pick up paper ....................................................................... 0
Solve image quality problems ............................................................................................... 0
Use the correct paper type setting in the printer driver .............................................. 0
Change the paper type setting for Windows ............................................. 0
Change the paper type setting for Mac .................................................... 0
Adjust color settings in the printer driver .................................................................. 0
Change the color theme for a print job .................................................... 0
Change the color options ....................................................................... 0
Use paper that meets HP specifications ................................................................... 0
Print a cleaning page ........................................................................................... 0
Print a cleaning page (LCD control panel) ................................................ 0
Print a cleaning page (touchscreen control panel) ...................................... 0
Calibrate the product to align the colors .................................................................. 0
Check the toner cartridges ..................................................................................... 0
Print the Supplies Status page ................................................................. 0
Inspect the print cartridge for damage ..................................................... 0
Repeating defects .................................................................................. 0
Use the printer driver that best meets your printing needs .......................................... 0
Solve performance problems ................................................................................................ 0
Factors affecting print performance ........................................................................ 0
viii ENWW
Print speeds ............................................................................................. 84
The product does not print or it prints slowly ............................................................... 85
The product does not print ......................................................................... 85
The product prints slowly ........................................................................... 86
Solve product connectivity problems ......................................................................................... 87
Solve direct-connect problems ................................................................................... 87
Solve network problems ........................................................................................... 87
Poor physical connection ........................................................................... 87
The computer is using the incorrect IP address for the product ........................ 87
The computer is unable to communicate with the product .............................. 88
The product is using incorrect link and duplex settings for the network ............ 88
New software programs might be causing compatibility problems .................. 88
The computer or workstation might be set up incorrectly ................................ 88
The product is disabled, or other network settings are incorrect ...................... 88
Solve wireless network problems ............................................................................... 89
Wireless connectivity checklist ................................................................... 89
The control panel displays the message: The wireless feature on this product
has been turned off .................................................................................. 90
The product does not print after the wireless configuration completes .............. 90
The product does not print, and the computer has a third-party firewall
installed .................................................................................................. 90
The wireless connection does not work after moving the wireless router or
product ................................................................................................... 90
Cannot connect more computers to the wireless product ................................ 91
The wireless product loses communication when connected to a VPN ............. 91
The network does not appear in the wireless networks list ............................. 91
The wireless network is not functioning ........................................................ 92
Service mode functions ........................................................................................................... 93
Service menu .......................................................................................................... 93
Service menu settings ................................................................................ 93
Restore the factory-set defaults ................................................................... 93
Restore the factory-set defaults (LCD control panel) ......................... 94
Restore the factory-set defaults (touchscreen control panel) .............. 94
Secondary service menu .......................................................................................... 94
Open the secondary service menu (LCD control panel) .................................. 94
Open the secondary service menu (touchscreen control panel) ....................... 94
Secondary service menu structure ............................................................... 95
Engine resets .......................................................................................................... 96
Engine test page ...................................................................................... 96
Cold reset ............................................................................................... 96
NVRAM initialization ................................................................................ 96
ENWW ix
Product updates ..................................................................................................................... 97
Appendix A Service and support ....................................................................................... 99
Hewlett-Packard limited warranty statement ............................................................................. 100
HP's Premium Protection Warranty: LaserJet print cartridge limited warranty statement .................. 102
Data stored on the print cartridge ........................................................................................... 103
End User License Agreement .................................................................................................. 104
OpenSSL ............................................................................................................................. 106
Customer support ................................................................................................................. 107
Repack the product .............................................................................................................. 108
Appendix B Product specifications ................................................................................... 109
Physical specifications .......................................................................................................... 110
Power consumption, electrical specifications, and acoustic emissions .......................................... 110
Environmental specifications .................................................................................................. 110
Appendix C Regulatory information ................................................................................. 111
FCC regulations ................................................................................................................... 112
Environmental product stewardship program ........................................................................... 113
Protecting the environment ...................................................................................... 113
Ozone production ................................................................................................. 113
Power consumption ............................................................................................... 113
Paper use ............................................................................................................. 113
Plastics ................................................................................................................. 113
HP LaserJet print supplies ....................................................................................... 113
Return and recycling instructions ............................................................................. 114
United States and Puerto Rico .................................................................. 114
Multiple returns (more than one cartridge) .................................. 114
Single returns .......................................................................... 114
Shipping ................................................................................ 114
Non-U.S. returns .................................................................................... 115
Paper .................................................................................................................. 115
Material restrictions ............................................................................................... 115
Disposal of waste equipment by users in private households in the European Union ...... 115
Chemical substances ............................................................................................. 115
Material Safety Data Sheet (MSDS) ......................................................................... 116
For more information ............................................................................................. 117
Declaration of conformity ...................................................................................................... 118
Declaration of conformity (wireless model) .............................................................................. 120
Certificate of Volatility .......................................................................................................... 122
x ENWW
Safety statements ................................................................................................................. 123
Laser safety .......................................................................................................... 123
Canadian DOC regulations .................................................................................... 123
VCCI statement (Japan) .......................................................................................... 123
Power cord instructions .......................................................................................... 123
Power cord statement (Japan) ................................................................................. 123
EMC statement (Korea) .......................................................................................... 124
Laser statement for Finland ..................................................................................... 125
GS statement (Germany) ........................................................................................ 125
Substances Table (China) ....................................................................................... 126
Restriction on Hazardous Substances statement (Turkey) ............................................. 126
Additional statements for wireless products .............................................................................. 127
FCC compliance statement—United States ................................................................ 127
Australia statement ................................................................................................ 127
Brazil ANATEL statement ........................................................................................ 127
Canadian statements ............................................................................................. 127
European Union regulatory notice ........................................................................... 127
Notice for use in France ......................................................................................... 128
Notice for use in Russia ......................................................................................... 128
Korean statement .................................................................................................. 128
Taiwan statement .................................................................................................. 129
Index ............................................................................................................................... 131
ENWW xi
List of tables
Table 1-1 Sequence of operation ............................................................................................................ 4
Table 2-1 DC controller connectors ....................................................................................................... 32
Table 2-2 Major components ............................................................................................................... 34
Table 2-3 Repetitive image defects ........................................................................................................ 41
Table 2-4 Event-log messages ............................................................................................................... 64
Table 2-5 Secondary Service menu ....................................................................................................... 95
Table B-1 Physical specifications ......................................................................................................... 110
Table B-2 Environmental specifications ................................................................................................ 110
ENWW xiii
List of figures
Figure 1-1 Product systems ..................................................................................................................... 2
Figure 1-2 Product components ............................................................................................................... 3
Figure 1-3 Engine control system components ........................................................................................... 5
Figure 1-4 DC controller circuit diagram .................................................................................................. 6
Figure 1-5 Low-voltage power supply ...................................................................................................... 7
Figure 1-6 High-voltage power supply ..................................................................................................... 8
Figure 1-7 Laser/scanner system ............................................................................................................. 9
Figure 1-8 Image-formation system ........................................................................................................ 10
Figure 1-9 Image-formation process ...................................................................................................... 11
Figure 1-10 Primary charging ............................................................................................................... 12
Figure 1-11 Laser-beam exposure ......................................................................................................... 12
Figure 1-12 Development ..................................................................................................................... 13
Figure 1-13 Primary transfer ................................................................................................................. 14
Figure 1-14 Secondary transfer ............................................................................................................ 14
Figure 1-15 Separation from the ITB ...................................................................................................... 15
Figure 1-16 Fusing .............................................................................................................................. 15
Figure 1-17 ITB cleaning ..................................................................................................................
Figure 1-18 Drum cleaning .................................................................................................................. 17
Figure 1-19 Pickup-and-feed system ....................................................................................................... 18
Figure 2-1 DC controller connectors ...................................................................................................... 32
Figure 2-2 Major components .............................................................................................................. 34
Figure 2-3 Timing diagram ................................................................................................................... 36
Figure 2-4 Circuit diagram ................................................................................................................... 37
.... 16
ENWW xv
1 Theory of operation
This chapter presents an overview of the major components of the printer and includes a detailed
discussion of the image-formation system.
Basic operation
●
Engine control system
●
Laser/scanner system
●
Image-formation system
●
Pickup-and-feed system
●
USB flash drive
●
ENWW 1
Basic operation
Major product systems
The product includes the following systems:
Engine control system
●
Laser/scanner system
●
Image-formation system
●
Pickup-and-feed system
●
Figure 1-1 Product systems
LASER/SCANNER SYSTEM
ENGINE CONTROL
SYSTEM
IMAGE-FORMATION SYSTEM
PICKUP-AND-FEED SYSTEM
2 Chapter 1 Theory of operation ENWW
Product components
Figure 1-2 Product components
1
3 4
2
5
14
13
Item Description Item Description
1 Fuser unit 8 Cassette
2 Delivery roller 9 Pickup roller
3 ITB drive roller 10 Separation roller
4 Photosensitive drum 11 Registration roller
5 Laser scanner assembly 12 Secondary transfer roller
6 Transfer pad 13 Fusing film
7 Intermediate transfer belt (ITB) 14 Pressure roller
12
11
10
9
8
7
6
ENWW
Basic operation
3
Sequence of operation
Table 1-1 Sequence of operation
Period Duration Purpose Remarks
WAIT From the time the power is
turned on or the door is
closed, until the printer is
ready for a print operation
STBY (Standby period) From end of the WAIT or
LSTR period until either the
print command is received
from the formatter or the
power is turned off
INTR (Initial rotation) From the time the print
command is received until the
media is picked up
PRINT From the end of INTR period
until the fuser paper sensor
detects the trailing edge of
paper
LSTR (Last rotation) From the end of the PRINT
period until the delivery motor
stops rotating
Clears the potential from the
drum surface, adjusts the
drum phase, and cleans the
ITB
Maintains the printer in
readiness for a print
command
Prepares the photosensitive
drum for printing
Forms the images on the
photosensitive drum and
transfers the toner image to
the print media
Moves the printed sheet out
of the printer
Detects the cartridge
presence and environment;
completes any required
calibration (color registration
control and image stability)
The printer enters sleep mode
when the formatter sends a
sleep command, and
performs color registration
and the image stability
control when the formatter
sends those commands
Performs image stabilization
at a specified print interval or
at specified times
The printer enters the INTR
period as soon as the
formatter sends another print
command
4 Chapter 1 Theory of operation ENWW
Engine control system
The engine control system coordinates all printer functions and drives the other three systems.
The engine control system contains the DC controller, high-voltage power-supply PCA, low-voltage
power-supply unit, and fuser control.
Figure 1-3 Engine control system components
Formatter
Engine-control system
Laser scanner system
DC controller
Low-voltage power supply
Image-formation system
High-voltage power supply
Fuser control
Pickup, feed and delivery
system
ENWW
Engine control system
5
DC controller
Figure 1-4 DC controller circuit diagram
Motor
AC input
Fuser
Low-voltage
power supply
Fuser
power supply
Driver
DC controller
Fan
Solenoid
Photointerrupter
Switch
ITB assembly
Laser scanner assembly
USB (NOTE)
High-voltage
T2 roller
Cartridge
power supply
NOTE: USB block for touchscreen-equipped models only.
Formatter
Control panel
6 Chapter 1 Theory of operation ENWW
Low-voltage power supply
Figure 1-5 Low-voltage power supply
AC input
Fuse
FU901
Fuse
FU801
Rectifying
circuit
Fuser control
circuit
Fuser power supply
PWSV
DC controller
Power switch
SW801
+24V
generation
circuit
Protection
circuit
+24VR
+24V
control circuit
+3.3V
generation
circuit
+3.3V
control circuit
Low-voltage power supply
REM24V
+24VA
VCTRLOFF
+3.3VC
+3.3VA+3.3VA
+3.3VB
Formatter
+24VA
Power switch
control circuit
ENWW
Engine control system
7
High-voltage power supply
Figure 1-6 High-voltage power supply
Primary charging bias circuit
Cartridge
Photosensitive drum
T1 pad
ITB cleaning
ass’y
T2 roller
Developing bias circuit
ITB
ITB cleaning brush
bias circuit
ITB cleaning roller
bias circuit
T2 bias circui
DC controller
T1 bias circuit
High-voltage power supply
8 Chapter 1 Theory of operation ENWW
Laser/scanner system
The formatter sends video signals to the DC controller, which controls the laser/scanner. When the
laser/scanner system receives those signals, it converts them to latent images on the photosensitive
drum.
Figure 1-7 Laser/scanner system
Scanner mirror
Scanner motor assembly
Laser assembly
BD sensor
Photosensitive drum
(Y)
Photosensitive drum
(M)
Photosensitive drum
Laser failure detection
The optical unit failure detection sensor manages the laser/scanner unit failure-detection functions. The
DC controller identifies the laser/scanner unit failure and notifies the formatter if the laser/scanner unit
encounters the following conditions:
Scanner motor failure
●
BD failure
●
(C)
Photosensitive drum
(K)
DC controller
ENWW
Laser/scanner system
9
Image-formation system
The image-formation system forms a toner image on media. The product includes four toner cartridges
that contain the toner. Toner is applied in the following order, using only the colors necessary for a
specific image: yellow (Y), magenta (M), cyan (C), and black (K).
Figure 1-8 Image-formation system
High-voltage power supply
Fuser
DC controller
Laser scanner assembly
Cartridge
T2 roller
Image-formation process
Laser printing requires the interaction of several different technologies including electronics, optics, and
electrographics to provide a printed page. Each process functions independently and must be
coordinated with the other processes. Image formation consists of the following processes:
Latent-image formation
●
Development
●
Transfer
●
MCYK
T1 pad
Photosensitive drum
ITB
10 Chapter 1 Theory of operation ENWW
Fuser
●
ITB cleaning
●
Drum cleaning
●
These processes are divided into nine steps, which are shown in
on page 11 and described in the following sections.
Figure 1-9 Image-formation process
Delivery
Latent image formation
7. Fusing
Fuser
3. Development
Development
Transfer
6. Separation
5. Secondary transfer
Registration
2. Laser beam exposure
1. Primary charging
Photosensitive drum cleaning
9. Drum cleaning
4. Primary transfer
8. ITB cleaning
ITB cleaning
Figure 1-9 Image-formation process
: Media path
: Direction of drum rotation
: Block
: Step
Pickup
Latent-image formation stage
During the two steps that comprise this stage, a latent image is formed by applying a negative charge
to the photosensitive drum. You cannot see this image on the drum.
ENWW
Image-formation system
11
Step 1: primary charging
A high-voltage DC bias is applied to the primary charging roller, which is made of conductive rubber
and is in contact with the drum surface. As the roller moves across the drum, it applies the negative
charge to that surface.
Figure 1-10 Primary charging
Primary charging roller
Photosensitive drum
Step 2: laser-beam exposure
The laser beam scans the photosensitive drum to neutralize the negative charge on portions of the drum
surface. An electrostatic latent image is formed where the negative charge was neutralized.
DC bias
Figure 1-11 Laser-beam exposure
Unexposed area Exposed area
Developing stage
The developer roller comes in contact with the photosensitive drum and deposits toner on the
electrostatic latent image.
Laser beam
12 Chapter 1 Theory of operation ENWW
Step 3: development
Toner acquires a negative charge as a result of the friction from the developer roller rotating against the
developer blade. When the negatively charged toner comes in contact with the drum, it adheres to the
electrostatic latent image. When the toner is on the drum, the image becomes visible.
Figure 1-12 Development
Developer blade
Exposed area
Unexposed area
Developer roller
DC negative bias
Unexposed area
Exposed area
Photosensitive drum
ENWW
Image-formation system
13
Transfer stage
Step 4: primary transfer
The toner image on the photosensitive drum is transferred to the ITB. The DC positive bias is applied to
the primary transfer pad. The negatively charged toner transfers to the ITB from the drum surface.
Figure 1-13 Primary transfer
Photosensitive
T1 pad
drum
ITB
T1 bias
Step 5: secondary transfer
The toner image on the ITB is transferred to the print media. The DC positive bias is applied to the
secondary transfer roller. As the media passes between the secondary transfer roller and the ITB, the
toner image is transferred to the media.
Figure 1-14 Secondary transfer
Media
Secondary transfer roller
DC bias
ITB
ITB drive roller
14 Chapter 1 Theory of operation ENWW
Step 6: separation from the ITB
The elasticity of the print media and the curvature of the ITB drive roller cause the media to separate
from the ITB.
Figure 1-15 Separation from the ITB
Media
Secondary transfer roller
Fusing stage
Until the fusing stage is complete, the image is not permanently affixed to the print media. The toner
can be easily smudged until the heat and pressure of the fusing process fix the image to the sheet.
Step 7: fusing
ITB
ITB drive roller
The product uses an on-demand fixing method to fix the toner image onto the media. The toner image
is permanently affixed to the print media by heat and pressure.
Figure 1-16 Fusing
Fuser film
Fuser heater
Toner
Paper
Pressure roller
ENWW
Image-formation system
15
ITB cleaning stage
Step 8: ITB cleaning
The ITB cleaning roller and the cleaning brush are applied with the DC positive bias to charge the
residual toner positive. Because the primary transfer pad is also applied with the DC positive bias, the
positively charged residual toner is reverse-transferred to the photosensitive drum from the ITB surface.
Figure 1-17 ITB cleaning
Positive potential waste toner
Negative potential waste toner
Partition sheet
ITB cleaning brush
Sweeper strip
DC bias
Cartridge
Photosensitive drum
ITB cleaning roller
IT B
DC bias
16 Chapter 1 Theory of operation ENWW
Drum cleaning stage
Not all of the toner is removed from the photosensitive drum during the transfer stage. During the
cleaning stage, the residual, or waste, toner is cleared from the drum surface to prepare the surface for
the next latent-image formation.
Step 9: drum cleaning
The cleaning blade scrapes the residual toner off the surface of the photosensitive drum and deposits it
in the waste-toner container. The drum is now clear and is ready for the next image-formation process.
Figure 1-18 Drum cleaning
Cleaning blade Blowout seal
Photosensitive
drum
ENWW
Image-formation system
17