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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
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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.
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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.
ENWWiii
Table of contents
1 Theory of operation .......................................................................................................... 1
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
●
ENWW1
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
2Chapter 1 Theory of operationENWW
Product components
Figure 1-2 Product components
1
34
2
5
14
13
ItemDescriptionItemDescription
1Fuser unit8Cassette
2Delivery roller9Pickup roller
3ITB drive roller10Separation roller
4Photosensitive drum11Registration roller
5Laser scanner assembly12Secondary transfer roller
6Transfer pad13Fusing film
7Intermediate transfer belt (ITB)14Pressure roller
12
11
10
9
8
7
6
ENWW
Basic operation
3
Sequence of operation
Table 1-1 Sequence of operation
PeriodDurationPurposeRemarks
WAITFrom 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
PRINTFrom 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
4Chapter 1 Theory of operationENWW
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
6Chapter 1 Theory of operationENWW
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
8Chapter 1 Theory of operationENWW
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
10Chapter 1 Theory of operationENWW
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 areaExposed area
Developing stage
The developer roller comes in contact with the photosensitive drum and deposits toner on the
electrostatic latent image.
Laser beam
12Chapter 1 Theory of operationENWW
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
14Chapter 1 Theory of operationENWW
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
16Chapter 1 Theory of operationENWW
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 bladeBlowout seal
Photosensitive
drum
ENWW
Image-formation system
17
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