Oki C9200 User manual

41388601TH Rev.2A 1 / 157
C9000 Series
Color LED Page Printer
Service Manual
ODA
05-18-200 Based on Rev.2

41388601TH Rev.2A2 /
1 2000-12-05 ISSUE EM3 Murakami
2 2000-12-13 8 Correction of errors in K Yamazaki
the parts list
Rev.No. Date No.
Corrected items
Page Description of change Person in
charge
Document Revision History

41388601TH Rev.23 /
PREFACE
Thismaintenancemanualprovidesproceduresandtechniquesforthetroubleshooting,maintenance,and
repair of C9000.
This manual is written for maintenance personnel, but it should always be accompanied with the C9000
User’sManualforproceduresforhandlingandoperatingC9000.ForrepairingeachcomponentofC9000,
see the Troubleshooting manual.
[Notices]
The contents of this manual are subject to change without prior notice.
Althoughreasonableeffortshavebeentakenin the preparation of this manual to assure its accuracy, this
manual may still contain some errors and omissions. OKI will not be liable for any damage caused or
alleged to be caused, by the customer or any other person using this maintenance manual to repair,
modify, or alter C9000 in any manner.
[Warning]
Many parts of C9000 are very sensitive and can be easily damaged by improper servicing. We strongly
suggest that C9000 be serviced by OKI’s authorized technical service engineers.

41388601TH Rev.24 /
CONTENTS
1. SPECIFICATIONS ............................................................................................ 7
1.1 Basic System Configuration............................................................................................. 7
1.2 Printer Engine Specifications ........................................................................................... 8
1.3 Option Configuration ........................................................................................................ 9
1.4 Specifications................................................................................................................. 10
2. OPERATION DESCRIPTION ......................................................................... 12
2.1 Main Control Board (CRM-PWB) ................................................................................... 13
2.2 Engine Control Board (K73 PWB).................................................................................. 15
2.3 Power Units.................................................................................................................... 16
2.4 Mechanical Processes ................................................................................................... 17
2.4.1 Electrophotographic process............................................................................ 18
2.4.2 Paper running process ..................................................................................... 22
2.5 Sensor............................................................................................................................ 31
2.5.1 Paper related sensors ...................................................................................... 31
2.5.2 Other sensors................................................................................................... 32
2.6 Color Misalignment Correction....................................................................................... 33
2.7 Transfer Control Responds to Environmental Changes
(Room Temperatures and Relative Humidities)............................................................. 33
2.8 Paper Jam Detection ..................................................................................................... 34
2.9 Cover Opening............................................................................................................... 35
2.10 Toner Low Detection...................................................................................................... 36
2.11 Paper Size Detection ..................................................................................................... 37
2.12 Operation at Power-on................................................................................................... 38
2.12.1 Self-diagnostic test ........................................................................................... 38
2.13 Color Misalignment Detection ........................................................................................ 39
2.14 Version Read of Periodically Replaced Units ................................................................ 40
2.15 Life Counter for Replaceable Units ................................................................................ 40
2.16 Toner Consumption Detection ....................................................................................... 40
3. PARTS REPLACEMENT................................................................................ 41
3.1 Precautions in Replacing Parts...................................................................................... 41
3.2 Parts Layout................................................................................................................... 43
3.3 Replacing Parts..............................................................................................................50
3.3.1 Top cover.......................................................................................................... 51
3.3.2 LED Assy/ LED Assy spring ............................................................................. 52
3.3.3 Top cover unit................................................................................................... 53
3.3.4 Control panel Assy/ Control panel bezel/ LED control PWB/ Toner sensor/
Stack full sensor/ Control panel tape harness/ Eject roller............................... 54
3.3.5 Top cover handle/ Tope cover latch/ Top cover latch spring............................ 55
3.3.6 Eject guide Assy ............................................................................................... 56
3.3.7 Cassette Assy/ Blind cover/ Side cover R Assy ............................................... 57
3.3.8 Feed rollers....................................................................................................... 58
3.3.9 Left side cover .................................................................................................. 59
3.3.10 Face-up tray ..................................................................................................... 60
3.3.11 Front cover ....................................................................................................... 61
3.3.12 Rear cover ........................................................................................................ 62
3.3.13 Multipurpose tray Assy/ Multipurpose tray cover Assy/ Links/
Multipurpose tray top cover/ Multipurpose tray drive gear................................ 63
3.3.14 Drum contact Assys.......................................................................................... 64
3.3.15 Registration roller Assy (A)/ Registration drive gear (A)................................... 65

41388601TH Rev.25 /
3.3.16 Registration roller Assy (B)............................................................................... 66
3.3.17 Registration clutch, Registration motor Assy.................................................... 67
3.3.18 Cooling fan ....................................................................................................... 68
3.3.19 Color registration sensor Assy.......................................................................... 69
3.3.20 Duplex guide Assy............................................................................................ 70
3.3.21 Electrical chassis/ Electrical chassis cooling fan.............................................. 71
3.3.22 Printer engine controller PWB .......................................................................... 72
3.3.23 Printer unit chassis ........................................................................................... 73
3.3.24 Entrance cassette sensor actuator................................................................... 74
3.3.25 Entrance sensor PWB ...................................................................................... 75
3.3.26 Entrance MT sensor actuator and Entrance belt sensor actuator .................... 76
3.3.27 Main motor fan/ Fuser eject roller..................................................................... 77
3.3.28 Eject sensor Assy ............................................................................................. 78
3.3.29 Fuser latching handle (L).................................................................................. 79
3.3.30 Belt motor Assy ................................................................................................ 80
3.3.31 Fuser latching handle (R) ................................................................................. 81
3.3.32 Main motor Assy............................................................................................... 82
3.3.33 Contact Assy/ Side plate Assy.......................................................................... 83
3.3.34 Low voltage power supply ................................................................................ 84
3.3.35 High voltage power supply ............................................................................... 85
3.3.36 Main feed Assy ................................................................................................. 86
3.3.37 Fuser unit.......................................................................................................... 87
3.3.38 Belt unit............................................................................................................. 88
3.3.39 Duplex unit........................................................................................................ 89
3.3.40 CU Assy............................................................................................................ 90
4. Adjustment ....................................................................................................92
4.1 Maintenance Menu and Its Functions ............................................................................ 92
4.2 Short Plug Settings ........................................................................................................ 93
4.3 Printing Singly Using Controller-Equipped Printer ......................................................... 93
4.4 Adjustment after Part Replacement ............................................................................... 94
4.5 Color Balance Adjustment ............................................................................................. 95
4.6 EEPROM Replacement after CRM Board and K73 Board Replacement ...................... 97
5. Regular Maintenance ....................................................................................98
5.1 Parts to be Replaced Regularly ..................................................................................... 98
5.2 Cleaning......................................................................................................................... 98
5.3 Cleaning of LED Lens Array .......................................................................................... 98
5.4 Cleaning of Pick-up Roller ............................................................................................. 98
6. TROUBLESHOOTING PROCEDURES ......................................................... 99
6.1 Tips for Troubleshooting ................................................................................................ 99
6.2 Check Points before Correcting Image Problems.......................................................... 99
6.3 Tips for Correcting Image Problems .............................................................................. 99
6.4 Preparation for Troubleshooting .................................................................................. 100
6.5 Troubleshooting Flow................................................................................................... 100
6.5.1 LCD Message List .......................................................................................... 101
6.5.2 LCD message troubleshooting ....................................................................... 106
6.5.3 Image troubleshooting.................................................................................... 117
7. WIRING DIAGRAM...................................................................................... 129
7.1 Resistance Check ........................................................................................................ 129
7.2 Parts Layout on Boards ............................................................................................... 134
8. Parts List ...................................................................................................... 138

41388601TH Rev.26 /
Job
offset
MM
M
M
M
M
M
LED Head
Junction Board
Pulse Motors
Engine Controller
Low-Voltage
Power Unit
Fuser Unit
High-Voltage
Power Unit
2nd/3rd Tray/
Large-Capacity
Tray
Duplex Unit
Belt Unit
<Sensors, Switches and Thermistors>
Paper carrier sensors
Paper size detection
Fuser temperature detection
Ambient temperature and humidity detection
Toner remaining detection
Color registration sensor
ID, belt and fuser checks
C-ID
Unit
M-ID
Unit
Y-ID
Unit K-ID
Unit
C ID
M
Heater M ID
Y ID
K ID
Belt MT/
Registration
Hopping
Geared
motor
DC motor
Operator Panel
Centronics
USB
IDE
HDD
DC
FAN
Ethernet
ROM DIMM ×3
SDRAM DIMM ×4
Controller
Block
1. SPECIFICATIONS
1.1 Basic System Configuration
The basic system configuration of C9000 is illustrated in Figure 1.1.
Figure 1.1

41388601TH Rev.27 /
1.2 Printer Engine Specifications
The inside of the printer is composed of the followings:
• Electrophotographic Processor
• Paper Paths
• Controller Block (CU and PU)
• Operator Panel
• Power Units (High-Voltage Unit and Low-Voltage Unit)
Figure 1-2 shows the printer configuration.
Figure 1.2

41388601TH Rev. 2 8 /
1.3 Option Configuration
The followings are available as options on C9000.
(1) 2nd Tray/ 3rd Tray
(2) Duplex Unit
(3) Large-Capacity Tray
(4) Expansion Memory 64/128/256MB
(5) Internal Hard Disk
(6) Ethernet Board

41388601TH Rev.2 9 /
1.4 Specifications
(1)Dimensions Height: 18.11 in. Width: 26.22 in. Length: 24.65 in.
(2) Weight 158.7 lbs.
(3) Paper Type: Ordinary paper and transparencies (Recommended: ML OHP01)
Size: Postalcard,Legal13"or14",Executive,A4,A5,B5, A6,A3A3-Nobi,B4
(Only the 1st tray and the front feeder support A6 and postal card
sizes.)
Weight: 1st tray 55 kg to 90 kg (64 to 105g/m2)
Front feeder 55 kg to 140 kg (64 to 163g/ m2)
(4) Print Speed Color: 21 pages per minute (Transparency: 5 pages per minute)
Monochrome: 26 pages per minute (Transparency: 15 pages per minute)
Postal Card, Label, Thick Paper: 10 pages per minute
(5) Resolution 600 ×600 DPI / 600 x 1200 DPI (C9200 series) & 1200 x 1200 DPI (C9400 series)
(6) Power Input 100VAC ±10%
(7) Power Consumption Peak: 1400W Normal Operation: 550W (5% duty)
Idle: 150W Power Saving Mode: 50W
(8) Frequency 50Hz or 60Hz ±2%
(9) Noise Operating: 54 dB (without Second tray)
Standby: 45 dB
Power Saving: 43 dB
(10) Consumable Life Toner Cartridge: 15,000 pages (5% duty)
(in each of Y, M, C and K)
Image Drum: 39,000 pages (5% duty, Continuous printing)
(in each of Y, M, C and K)
(11) Parts Replaced Periodically Fuser Unit Assy: Every 80,000 pages
Belt Cassette Assy: Equivalent of 80,000 pages (3P/J)
Transfer Belt cartridge: 60,000 prints

41388601TH Rev.2 10 /
Temperature (ºF) RemarkTemperature (ºC)
Operating 50 to 89.6 10 to 32 17 to 27ºC (Temperatures to
assure full color print quality)
Non-Operating 32 to 109.4 0 to 43 Power-off
Storage (Max.OneYear) -14 to 109.4 -10 to 43 With drum and toner
Transport (Max. One Month) -20 to 122 -29 to 50 With drum and without toner
Transport (Max. One Month) -20 to 122 -29 to 50 With drum and toner
Relative Humidity (%) Max.Wet-Bulb Temperature (ºC) Remark
Operating 20 to 80 25 50 to 70%
(Humidities to assure full color print quality)
Non-Operating 10 to 90 26.8 Power-off
Storage 10 to 90 35
Transport 10 to 90 40
(12) Temperatures and Relative Humidities
Temperature
Humidity
(13 Printer Life 1,000,000 pages (on a A4 basis) or five years

41388601TH Rev.2 11 /
2. OPERATION DESCRIPTION
C9000,atandem color electrophotographic page printer, adopts technologiessuchas 4992-LED
array,OPC,drysingle-componentnon-magneticdeveloping,rollertransferandheat-compression
fusing. The printing method is black writing by shedding light on print areas.
Figure 2-1 provides the block diagram of this device.
Stacker Open
Microswitch
SUMI Card
Sensor/Microswitch
New C9000 Connector
Backup Roller
Thermistor
L-Side Color Registration Adjustment
AOUT3
R-Side Color Registration Adjustment
AOUT2
Eject Sensor Heater
Shutter Clutch
SHUTTER Regist
Clutch
R
SNS
PO
WER
C
UIF
PS
IZE
HV
OLT
JO
DEN
FS
ENS
TR
1OP
P5 P6
R
EG
BEL
THET
DU
PLEX
K73 Main Board
CP
UFL
PAR
TTEMP
SHU
TTER
D
CL
FC
OVER
DU
COV
PE
NDF
O
HP1
FF
POS
PA
PWID
M7L Board M7R Board
F
AN1
F
AN2
FF/
Registration
Motor
CO
VOPN
Right Side Cover
Open Microswitch
Upper Cover
Open Microswitch
(+38V cut)
S
W1
Y71 Head
Relay Board
TNRK
TNRY
STUCK POWER
PANEL
MPOW2 CPOW2
YPOW2
KPOW2
TNRM
TNRC
Stacker Full Sensor
Geared
Motor
Loading Clutch
Pickup Clutch
Carrier Sensor
Paper Width Sensor
Offset
Motor Hopping
Motor
Offset Zero Sensor
C73
I/F Board Finisher
A73 Retard Sensor Board
Lifter Sensor
Loading Sensor
Belt
Fuse
I DPOSK
I DPOSY
I DPOSM
I DPOSC
N71 Board
(charge elimination relay)
IDC
IDM
IDY
ID
D2 Green
D2Yellow
K
NBLT
4 x P73 Boards
AC
Input
AC
Input
Fan 3 (off-the-shelf)
Fan 2 (power eject)
Fan 1 (PU)
works as stepper
PEND
PNEND
Offset PE Sensor
Offset Sensor
STDUCOV
JO
BOFF
OPTN
KPOW
K1200
Y1200
M1200
MPOW
YPOW
ID
R
CL
HO
PFF
FR
PUCL
C1200
CPOW
F
ACE
K
L
E
D
H
E
A
D
L
E
D
H
E
A
D
L
E
D
H
E
A
D
L
E
D
H
E
A
D
Y
M
C
F
EED
PAPSIZ3-0
aVR
Paper Width Sensing Board
HOP
LIFT
MAIL
HOP(I
NSNS1)
H
UM
T
EMP
R71
Board
PAPIN(
INSNS2)
PSWR(
WRSNS)
TN
RFUL
GE
ARED
K IDU
Motor
JOB
OFFS
JOB
OFFPE
connected to next tray (no tray in lowest section)
connected to trays of up to 5th,
including 2nd tray
(does not exist in the lowest)
2nd Tray/3rd Tray
Large-Capacity Tray
Geared
Motor Loading
Carrier Clutch
(does not exist in the lowest)
Loading Clutch
V73 Board
Paper End
Paper Near
End
Cover Opem SW
Carrier Sensor
Paper Width Sensing Board
T9 Blue
T3 White
T4 Red
T5 Red
T8 Red
T2 Blue
T6
Yellow
Lifter Sensor
Loading Sensor
Retard Sensor
Board A73
T2 White
T10 Red
T1 Blue
T1 White
T7 White
T11
(does not exist in the lowest)
DUP-In Sensor
DUP Middle Sensor
DUP Front Sensor
DUP
DUP Front Clutch DUP Rear Clutch
D3 Blue
V73 Board
Duplex
D1 Blue
D1 White
Belt
Motor
P1Yellow
P1 White
P2
P2Yellow
P3 White
P2 Blue
P2 Red
P4
P4 Red
P4Yellow
P4 Blue/
White
P6 Brown
P7 Blue
P7 Gray
P7
P8
P7 Gray
attached to
sensor
P9
P9 Black
P10P10
P10 Brown
P11
P11 Blue
P11 White
P21P21
P22
P12P12
P12Yellow
P13
P13 Red
P14 P14Yellow
P14 Red
P15 Red
P16 Browm
P17 Red
attached to motor
P16
P5 Red
P18 Black
P19
P18
P17
P20
P18Yellow
P18 Red
P18 Blue
attached
to clutch
P19 White
P1
P19 Red
P20 White P20Yellow
P24 to P31
P23
Y1 White
Y2 Blue
Y1 White
S1 Gray
Heater Unit
Heat Roller
Thermistor
Sensor
Fuse
TH
ERM1
TH
ERM2
N
FU
LH
RTMP
LB
RTMP
C
N8
C
N9
C
N2
C
N1
High-Voltage
Power Supply
C
N5
CN4-
2,6-2
CN4-
1,6-1
AC
SW
S1
Low-Voltage
Power Supply
attached to fan
attached to fan
*1
attached to fan
attached to fan
attached to fan
Heat
Motor
FD
WPAP
Jam Sensor
P2 White
P4 Green
Fan 0 (power-on)
Face-Down Solenoid
Eject Solenoid
Removed-Edge Side
Removed-
Edge Side
P33 White
P33 Blue
Temperature Sensor
P33 Green
Fan 0 (power eject)
DUP_PAP
T6
Blue
White
connected to next tray (no tray in lowest section)
Geared
Motor Loading
Carrier Clutch
Loading Clutch
V73 Board
Paper End
Paper Near
End
Cover Opem SW
Carrier Sensor
Paper Width Sensing Board
T9 Blue
T3 White
T4 Red
T5 Red
T8 Red
T2 Blue
T6
Yellow
Lifter Sensor
Loading Sensor
Retard Sensor
Board A73
T2 White
T10 Red
T1 Blue
T1 White
T7 White
T11
*1
T6
Blue
White
Black
Removed-
Edge Side
White
Black
DUP Rear Sensor
Y6
Y5
Y3 Y4
P24 to P31
Y IDU
Motor M IDU
Motor C IDU
Motor
Motor
P17 Yellow
S2
Black Black
Black
Y4 Green
Y3YellowY3 Red
Y5 Blown
X71 Board
P24
P28
P25
P29
P26
P30
P27
P31
Operator
Panel
C Charge Elimination Lamp Fuse
M Charge Elimination Lamp Fuse
Y Charge Elimination Lamp Fuse
K Charge Elimination Lamp Fuse
P27
ACSW
Assy
FAN
RAM
CRM Board
ROM
HDD
LAN
USB
CENTRO
Figure 2.1

41388601TH Rev.2 12 /
2.1 Main Control Board (CRM-PWB)
Figure 2-2 provides the block diagram of the main control board (CRM-PWB).
PPC
750 L2
Cache
Delay
Delay
Buf
16244 Buf
16244
IF Bus
EEPROM
A
D
Cont
Y, M, C and K Video Data PU-CU I/F,
Operator Panel
A/D,Cont
A/D, Cont(SUB Bus)
14.31818MHz
Crystal Resonator CY2292
CY2308
FET SW
162212
FLASH ROM
FLASH DIMM
×3
SDRAM DIMM
·4
IMI1530
Fluctuation Circuit
Internal-CLK-
Setting
Resistance
Reset
DS1834
to C2 and
3.3V ICs
to 5V ICs
PU Board Connector, 200 Pins
Inverter RESET-P
2.0V
Regulator
2.5V
Regulator
C1 LSI
MHM
2030-002
C2 LSI
MHM2031-002
CDC516
80MHz
LVC244
LVC161284
Centro USB
L60851
PCI Bus
LAN Board
IDE
HDD
LVC245
80MHz
80MHz
3.3V5V
40MHz
48MHz
33MHz 33MHz
·2
SPD
80MHz
×280MHz
×16
A,Cont
A,Cont A,Cont A,Cont
DDD
Figure 2.2

41388601TH Rev.2 13 /
(1) CPU
The CPU is 64-bit bus RISC processor PowerPC750, which receives an input of 80MHz
(=BUS CLK) and operates at 400MHz, four-times the input.
(2) Secondary Cache SRAM
SRAM is included as a secondary cache of the CPU on the board.
(3) ROM
The ROM is inserted into the three 168-pin DIMM slots. The slot A is for a program ROM
and the slot B is for the Japanese Kanji font. The slot C is not assigned.
(4) RAM
The RAM is inserted into the four 168-pin DIMM slots. The DIMMs must be fitted in
descending order of the type No. labeled on each of them into the slots 1, 3, 2 and 4.
SDRAM DIMM Specifications:
Speed: PC100 or more
Capacity: 64/128/256MB
Configuration: Without parity and ECC. Requires the SPD information. Number of
chips contained = 8 or 16.
(5) EEPROM
TheEEPROM (16Kb),an8-pinDIPpackage,isinsertedintotheICsocket supplying the 3.3V
power. Settings for controlling the controller block are stored in the memory.
(6) Flash ROM
A2-megabyteflashROMissurface-mountedontheCRMboard. TheflashROM,composed
of four chips of 256 kilo x 16 bits, can store fonts and macros.
(7) Memory Control LSI (CI)
A696-pinBGApackageASICmadebyNEC, which is equipped with a cooling heat sink and
mainly controls the CPU I/F, memory, video data compression and decompression, and PU-
video I/F.
(8) Interface Control LSI (C2)
A BGA package ASIC made by Toshiba, which controls the PU command I/F, operator panel
I/F, IDE I/F, Centronics I/F, USB I/F, PCI I/F, EEPROM and SPD (SDRAM DIMM) I/F.
(9) IDE HDD
An IDE connector is surface-mounted on the board to which an IDE HDD, assembled using
molds for the purpose, is connected. The IDE HDD is used for storing font data, spooling
edited video data temporarily and registering form data.
(10) PCI Bus Option
TwoPCII/Fslotsareprovidedforoptionboarduse. Thebus,whichusesanOkiDataoriginal
connector, can accept an Ethernet board.
(11) Host Interface
Standard: Centronics two-way parallel I/F (IEEE-1284-compliant)
USB (USB1.1-compliant)
Additional Board: (connected to PCI BUS)
Ethernet Board

41388601TH Rev.2 14 /
Figure 2.3
Theengine controlblock(PU)is controlledbythe enginecontrolboard(K73PWB)whichconsists
of a CPU (MSM66Q577), general LSI chip, flash ROM, EEPROM, pulse motor drivers, and video
memory (see Figure 2.3).
(1) CPU
This, a 16-bit CPU with an AD converter (OKI MIM66Q577), controls the entire system.
(2) General LSI
This LSI (MG63P011-001LA), which is contained in the printer engine control block,
incorporates 4 megabits of video memory and has functions such as engine-controller
interfacing, LED interfacing, motor control, sensor input, video memory control, main scan
color misalignment correction, skew correction and high-voltage power supply control.
2.2 Engine Control Board (K73 PWB)
K Head I/F
Y Head I/F
M Head I/F
C Head I/F
Motor Driver
Motor Driver
DC Motor Driver DC Motor
(Geared Motor)
9x Pulse Motors
LSI
(VIDEO MEM
Containing
4Mbit DRAM)
High-Voltage Power Supply
Serial Interface (2 channels)
Toner and ID sensors ID check
CU I/F
Fuse Cut Driver
EEPROM
D/A
48MHz
32bit Video I/F
Heater control
CPU BUS
Control Panel
8Mbit(1MByte)
FLASH
CPU
MSM66Q577
A/D CON
Duplex
Cassette 2/3
28MHz
Paper Feed System Sensors
(Paper Feed, Paper Registration and Eject Sensors)
MT Sensor (Stage position and paper empty)
Cassette 1 Sensor (Paper empty and near empty)
Shutter, clutch, belt and fuser checks
Cassette size
Analog output
(Color registration sensor adjustment)
Analog input
(Temperature change) Analog Input
Switch
Analog input (OHP)
Analog input (Various densities)
Fan control
Cover front/upper open
Stacker full
Test switch
(Power supply cooling)
Motor interruption
UART interruption
256Kbit(32KByte)
SRAM
× 2

41388601TH Rev.2 15 /
Output voltage Use for
+3.3 V Logic circuit power supply
+3.8V Logic circuit power supply
+5 V Motor and drive voltage for high-voltage power supply
+32 V OP Amp, High-voltage power supply
+12 V LED head
Output Voltage Use for Remarks
CH -900 to -1400±50V Voltage to charging roller
DB Y, M, C: -10 to -400V/+300V Voltage to developing roller
K: -10 to -400V/+300V
SB Y, M, C: -100 to -700/0V Voltage to toner supplying roller
TR 0 to 7KV Voltage to transfer roller Variable
(2) High-Voltage Power Unit
Thiscircuitgenerates the following 34V or more voltages, which arerequiredfor electropho-
tographic process, according to control sequences from the control board.
2.3 Power Units
Thereisalow-voltagepower unit, which consists of anACfiltercircuit,low-voltagepowercircuit
andheaterdrivercircuit,andahigh-voltagepowerunitwhichsuppliesahigh-voltagepowercircuit.
(1) Low-Voltage Power Unit
This circuit generates the following voltages:
(3) Flash ROM
8 megabits of flash ROM (MBM29F800TA-70) which stores PU programs.
(4) EEPROM
4kilobitsofEEPROM(NM93C66N-NW)whichismountedontheboardwithanICsocketand
stores correction values.
(5) Pulse Motor Driver
The pulse motor driver (A2918, A2919, A3955) drives nine pulse motors to revolve the EP
and carry media.
(6) SRAM
This SRAM (62256LFP-7LL) is used as working memory of the CPU.

41388601TH Rev.2 16 /
2.4 Mechanical Processes
Figure 2.4 shows the mechanical processes of the printer.
Figure 2.4
Paper Eject Roller
Paper Ejection
(Face down)
Power Supply
Charging Roller
Cleaning Blade
Paper Path
Selection
Heat Roller
Ejection
Roller Fusing
Backup Roller
Control Signals
LED Head
Developing Roller
Power Supply
Toner Cartridge
Transfer Roller Registration
Roller 1
Paper loading
Hopping Roller
Power
Supply Registration
Roller 2
Paper Ejection Fusing Cleaning Transfer Paper carriage Paper advance
Paper traveling
OPC drum revolution
Transfer
Charging
Expose
Development
Cleaning
Paper Eject Sensor Paper Feed Sensor 1
Paper Ejection
(Face up)
Paper Feed Sensor 2
Multipurpose
Tray
Paper Cassette
Paper
registration Paper
registration
(MT, 1ST, 2ND)
Write Sensor
x 4
K YMC

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2.4.1 Electrophotographic process
(1) Electrophotographic process
The following is the outline of electrophotographic process:
1Charging
DCvoltageisappliedtothechargingrollerandthesurfaceoftheOPCdrumisnegatively
and evenly charged.
2Exposure
The LED head, under image signals, emits light to the negatively charged surface of the
OPC drum. The radiated portions of the drum surface attenuate in negative charge
according to the intensity of the light and, based on the surface potentials, a latent
electrostatic image is formed on the drum surface.
3Development
Negatively charged toner contacts the OPC drum and, by electrostatic force, adheres to
the latent electrostatic image to form a clear image on the drum surface.
4Transfer
PaperisplacedonthesurfaceoftheOPCdrum,andpositively,oroppositetothepolarity
of the toner, charged by the transfer roller on its back to transfer the toner image to the
paper.
5Cleaning
The cleaning blade removes residual toner from the OPC drum after the transfer.
6Fusing
The toner image on the paper is fused into place through the application of heat and
pressure to it.

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(3) Exposure
The negatively charged surface of the OPC drum is radiated with light from the LED head.
The negative charge of the radiated portions of the drum surface attenuates in response to
the intensity of the light and a latent electrostatic image responsive to the potentials of the
surface is formed on the drum surface.
(2) Charging
NegativeDCvoltageisappliedtothechargingrollercontactingthesurfaceoftheOPCdrum.
Charging roller
OPC drum
Power
Unit
Power
Unit
LED head
Charging roller
OPC drum
LED head
OPC drum
Paper

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2The developing blade removes excess toner from the developing roller and a thin layer
of remaining toner is formed on the developing roller.
3The toner is drawn by the latent electrostatic image at the contact portion between the
OPC drum and the developing roller.
The latent electrostatic image on the drum surface is made visible with the toner.
(4) Developing
By the adhesion of toner to the latent electrostatic image on the drum surface, the image is
changedtoatonerimage. ThedevelopingisprocessedatthecontactpartbetweentheOPC
drum and the developing roller.
1The sponge roller causes toner to adhere to the developing roller. The toner becomes
negatively charged.
Charging roller Developing blade
Developing roller
OPC drum
Sponge roller
Developing roller
(5) Transferring
The transfer roller, which is made of conductive sponge, presses paper against the surface
of the OPC drum and brings the paper into intimate contact with the drum surface.
The paper is placed on the drum surface and positively (opposite to the charge of the toner)
charged by the transfer roller on its back.
Applyingpositivehighvoltage from the power supplytothetransferrollermoves the positive
charge induced by the transfer roller to the paper surface at the contact portion between the
transferrollerandthepaper,thepapersurfacedrawingthenegativelychargedtonerfromthe
drum surface.
Transfer roller
Paper
Carrier belt
OPC drum
Power unit

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(7) Cleaning
Non-fused,residualtonerontheOPCdrumisscrapedwiththecleaningbladeandcollected
in the waste toner area of the toner cartridge.
Cleaning blade
Waste toner box
(8) Cleaning
Residual toner on the transfer belt is scraped with the cleaning blade and collected in the
waste toner box of the transfer belt unit.
Waste toner area
(6) Fusing
When passed between the heat roller and the backup roller, the toner image transferred to
the paper is fused into place by the application of heat and pressure to it.
The Teflon coated heat roller is heated by the built-in heat roller of 800W/backup roller of
500W (halogen lamp). The fusing temperature is controlled by the sum of the temperature
detected by the thermistor moving over the surface of the heat roller and the temperature
detectedbythe thermistor movingoverthesurfaceof the backuproller. Athermostat,which
is provided for safety, becomes open by a heat roller temperature rise of not less than fixed
degreesandcutsoffvoltagesupplytotheheater. Thebackuprollerisbeingpressedagainst
the heater by the pressure springs on both sides.
Thermistor
Thermostat
Thermistor
Paper
Backup roller
Thermostat
Heat roller