Okidata C7000 Service Manual

C7000 Series

Color LED Page Printer

SERVICE MANUAL

OkiData

01-23-2001 based on Rev.4

41316401TH Rev.4A 1 / 186

Document Revision History

Rev.No. Date

1

2000-05-29 ISSUE E4 Yamazaki

No.

Corrected items

Page Description of change

Person in

charge

2 2000-05-31 E4 Murakami
3 2000-12-04 NIP9 Yamazaki
4 2000-12-15 NIP9 Yamazaki

41316401TH Rev.4 2 /

PREFACE

This manual describes the procedures for the maintenance of the C7000 Series of printers.
The document is produced for maintenance personnel use. For details on the procedures for handling the

C7000 Series of printers, see its user documentation.

Note!

• The descriptions in this manual are subject to change without prior notice.

• In preparing the document, efforts have been made to ensure that the information in it is accurate.
However, there may be errors in the document. Oki Data assumes no responsibility for any
damage resulting from, or claimed to be the results of, those repairs, adjustments or modifica­tions to the printers which are made by users using the manual.

• The parts used for the printers are electrostatic sensitive and, if handled improperly, may be damaged.
It is strongly recommended that the products be maintained by Oki Data Authorized Repair Centers

Oki Data.

.

41316401TH Rev.4 3 /

CONTENTS

1. CONFIGURATIONS ......................................................................................... 7

1.1 System Configuration....................................................................................................... 7

1.2 Printer Configuration ........................................................................................................8

1.3 Option Configuration ........................................................................................................ 9

1.4 Specifications................................................................................................................. 10

2. OPERATION DESCRIPTION ......................................................................... 12

2.1 Main Board (CRM PWB)................................................................................................ 13

13

2.2 Engine Controller Board (K71 PWB).............................................................................. 15

2.3 Power Units.................................................................................................................... 16

2.4 Mechanical Processes .................................................................................................. 17

2.4.1 Electrophotographic process............................................................................ 18

2.4.2 Paper running process ..................................................................................... 23

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-Open ...................................................................................................................35

2.10 Toner Low Detection...................................................................................................... 36

2.11 Page 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 Units Replaced Periodically ................................................................ 40

2.15 Life Count for Units Replaced Periodically..................................................................... 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..............................................................................................................49

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 Sensors/

Stacker Full Sensor/ Control Panel/ Control Panel Tape Harness/ Eject Rollers. 54

3.3.5 Top Cover Handle/ Top Cover Latch/ Top Cover Latch Spring........................ 55

3.3.6 Eject Guide Assy .............................................................................................. 56

3.3.7 Cassette Assy/ Front Cover Assy/ Front Cover Inner Baffle ........................... 57

3.3.8 Retard Pad Assy/ Retard Pad Assy Spring ...................................................... 58

3.3.9 Feed Roller and Nudger Roller......................................................................... 59

3.3.10 Rear Cover....................................................................................................... 60

3.3.11 Face-Up Tray.................................................................................................... 61

3.3.12 Left Side Cover................................................................................................. 62

3.3.13 Right Side Cover .............................................................................................. 63

3.3.14 Multipurpose Tray Assy/ Multipurpose Tray Cover Assy/ Links/

Multipurpose Tray Top Cover/ Multipurpose Tray Drive Gear.......................... 64

3.3.15 Drum Contact Assys .......................................................................................... 65

3.3.16 Registration Roller Assy (A)/ Registration Drive Gear (A)................................ 66

3.3.17 Registration Roller Assy (B) ............................................................................. 67

3.3.18 Registration Clutch and Registration Motor Assy............................................. 68

3.3.19 Main Cooling Fan ............................................................................................. 69

41316401TH Rev.4 4 /

3.3.20 Color Registration Sensor Assy........................................................................ 70

3.3.21 Duplex Guide Assy........................................................................................... 71

3.3.22 Electrical Chassis Cooling Fan......................................................................... 72

3.3.23 Printer Engine Controller PWB......................................................................... 73

3.3.24 Printer Unit Chassis.......................................................................................... 74

3.3.25 Entrance Cassette Sensor Actuator................................................................. 75

3.3.26 Entrance Sensor PWB...................................................................................... 76

3.3.27 Entrance MT Sensor Actuator and Entrance Belt Sensor Actuator.................. 77

3.3.28 Fuser Exit Roller............................................................................................... 78

3.3.29 Exit Sensor Assy .............................................................................................. 79

3.3.30 Fuser Latching Handle (L)................................................................................ 80

3.3.31 Belt Motor Assy ................................................................................................ 81

3.3.32 Fuser Latching Handle (R) ............................................................................... 82

3.3.33 Main Motor Assy............................................................................................... 83

3.3.34 Main Feeder Drive Motor.................................................................................. 84

3.3.35 Contact Assy/ Left Plate Assy .......................................................................... 85

3.3.36 Low Voltage Power Supply............................................................................... 86

3.3.37 High voltage power supply ............................................................................... 87

3.3.38 Main Feed Assy................................................................................................ 88

3.3.39 Cassette/ Left Guide Assy................................................................................ 89

3.3.40 Cassette/ Right Guide Assy.............................................................................. 90

3.3.41 Fuser Unit......................................................................................................... 91

3.3.42 Belt Unit............................................................................................................ 92

3.3.43 Duplex Unit....................................................................................................... 93

3.3.44 Guide Rails (L) and (R)..................................................................................... 94

3.3.45 Duplex Transport Assembly ............................................................................. 95

3.3.46 CU Assy............................................................................................................ 97

4. ADJUSTMENTS ............................................................................................. 99

4.1 Maintenance Modes and Their Functions...................................................................... 99

4.1.1 Maintenance menu........................................................................................... 99

4.1.2 Engine maintenance mode............................................................................. 100

4.1.2.1 Operator panel................................................................................... 100

4.1.2.2 General self-diagnosis mode (level 1)............................................. 100

4.1.2.2.1 Entering self-diagnosis mode (level 1) ............................ 100

4.1.2.2.2 Exiting self-diagnosis mode ............................................ 100

4.1.2.3 Switch scan test................................................................................. 101

4.1.2.4 Motor and clutch test ......................................................................... 104

4.1.2.5 Test printing .................................................................................... 106

4.1.2.6 NVM initialization............................................................................ 110

4.1.2.7 Consumable counter display........................................................... 111

4.1.2.8 Consumable counter display - continuous ...................................... 111

4.1.2.9 Error Messages and their Details.................................................... 112

4.1.3 CRM board adjustments................................................................................. 116

4.1.3.1 Short plug settings .......................................................................... 117

4.1.3.2 Printings singly using controller-equipped printer ........................... 117

4.2 Adjustments after Parts Replacement ......................................................................... 118

4.2.1 Precautions in replacing engine controller board ........................................... 118

4.2.2 Precautions in replacing EEPROM................................................................. 118

4.2.3 EEPROM replacement after CRM board replacement................................... 119

4.3 Color Balance Adjustment ........................................................................................... 120

5. PERIODIC MAINTENANCE ......................................................................... 122

5.1 Parts Replaced Periodically ......................................................................................... 122

5.2 Cleaning....................................................................................................................... 122

5.3 Cleaning LED Lens Array ............................................................................................ 122

5.4 Cleaning Pickup Roller................................................................................................. 122

41316401TH Rev.4 5 /

6. TROUBLESHOOTING PROCEDURES ....................................................... 123

6.1 Before Troubleshooting................................................................................................ 123

6.2 Checking before Troubleshooting Image Problems..................................................... 123

6.3 Precautions in Troubleshooting Image Problems ........................................................ 123

6.4 Preparation for Troubleshooting .................................................................................. 123

6.5 Troubleshooting ........................................................................................................... 123

6.5.1 LCD messages list.......................................................................................... 124

6.5.2 Preparation for troubleshooting ...................................................................... 129

6.5.3 Troubleshooting image problems ................................................................... 140

7. CONNECTION DIAGRAM............................................................................154

7.1 Resistance Checks ...................................................................................................... 154

7.2 Program/Font ROM Layouts ........................................................................................ 158

8. Parts List......................................................................................................162

APPENDIX A CENTRONICS PARALLEL INTERFACE................................... 178

APPENDIX B 2ND/3RD TRAY MAINTENANCE .............................................. 182

41316401TH Rev.4 6 /

M

M

M

M

M

M

M

M

LED Head

Centronics I/F

USB I/F

2 × Option Slots

Junction Board

Pulse Motor

Engine Control

Low V oltage

Power Unit

Fuser

Unit

High V oltage

Power Unit

2nd/3rd T ra y

Duplex

Unit

Belt

Unit

<Sensors, Switches and Thermistors>

Paper size sensor (4 bits)

Paper empty sensor

Paper near empty sensor

MT paper empty sensor

FF home switch

Loading sensor 1

Loading sensor 2

C-ID

Unit

M-ID

Unit

Y-ID

Unit

K-ID

Unit

C ID M ID Y ID K IDBelt Heat

MT/

Registration

Hopping

Operator Panel

3 × ROM

DIMMs

4 × RAM

DIMM

IDE

I/F(HDD)

DC Fan

Note

Note Option Slot:

LAN Card made by JCI

1. CONFIGURATIONS

1.1 System Configuration

Figure 1-1 shows the system configuration of the C7000 Series of printers.

Figure 1-1

41316401TH Rev.4 7 /

1.2 Printer Configuration

The inside of the printers 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.

B

B

A

B

B

A

A

Figure 1-2

41316401TH Rev.4 8 /

1.3 Option Configuration

The following options are available for the C7000 Series of printers.

(1) 2nd Tray/ 3rd Tray

(2) Duplex Unit

(3) Expansion Memory 64/128/256 MB

(4) Internal Hard Disk

(5) OkiLAN 6200e NIC

41316401TH Rev.4 9 /

1.4 Specifications

(1) External Dimensions Height: 16.9 in. Width: 16.9 in. Length: 24.4 in.

(2) Weight 92.5 lbs.

(3) Papers Type: Ordinary paper, Transparencies (Recommended: MLOHP01)

(4) Print Speed Color: 12 pages per minute (Transparency: 5 pages per minute)

(5) Resolution (C7200) = 600 × 600 -//- (C7400) 1200 x 1200 dots per inch

(6) Power Input 100VAC ±10%

(7) Power Consumption Peak:1300W Normal Operation: 400W (5% duty)

Size: Postal card, Legal 13" or 14", Executive, A4, A5, B5, A6 (Only

the 1st tray and the front feeder support A6 and postal-card
sizes.)

Weight:1st tray55 kg to 90 kg (64 to 105g/m2)

Front feeder55 kg to 140 kg (64 to 163g/ m2)

Monochrome: 20 pages per minute (Transparency: 12 pages per minute)
Postal Card, Label, Thick Paper: 8 pages per minute

Idle: 110W Power Saving Mode:45W or less

(8) Frequency 50Hz or 60Hz ±2%

(9) Noise Operation: 54 dB (Without second tray)

Standby: 45 dB
Power Saving:43 dB

(10) Consumable Life Toner Cartridge: 10,000 pages (5% duty) (each of Y, M, C and K)

Image Drum: 30,000 pages (Continuous printing)

(each of Y, M, C and K)

(11) Parts Replaced Periodically Fuser Unit Assy: Every 60,000 pages

Transfer Belt Assy: Equivalent of 60,000 pages (3 pages/job)

41316401TH Rev.4 10 /

(12) Temperatures and Relative Humidities
Temperature

Temperature Condition

Temperature (˚F) Temperature (˚C) Remark

Operation 50 to 89.6 10 to 32 17 to 27˚C

(Temperatures to assure full

color print quality)
Non-Operation 32 to 109.4 0 to 43 Power-off
Storage (Max. One Year) -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

Humidity

Humidity Condition

Relative Humidity Max. Wet-Bulb Remark

(%) Temperature(˚C)

Operation 20 to 80 25 50 to 70% (Humidities to assure full

color print quality)
Non-Operation 10 to 90 26.8 Power-off
Storage 10 to 90 35
Transport 10 to 90 40

(13) Printer Life 600,000 pages (on a A4-size basis) or five years

41316401TH Rev.4 11 /

2. OPERATION DESCRIPTION

N71 Board

Belt

Fuse

K Fuse

Y Fuse

M Fuse

C Fuse

JODEN

14P

Paper Tray 1 Paper Empty

Paper Tray 2 Near Empty

3P

3P

WHITE

BLUE

OPTION

7P

7P

BLUE

BLUE

BLUE

WHITE

WHITE

WHITE

RED

9P

10P 14P 14P

4P

3P

22P

11P 2P

8P

YELLOW

YELLOW

FAN1 (Pr)

HUM/

TMP

3P

FAN2 (Pow)

Plate Senosr

Gray

Blue

Z7L

Z7R

9P

R71 Board

Manual Bypass Feeder (MBF)

Hopping

Motor

FF/Regist

Motor

K IDU

Motor

Y IDU

Motor

M IDU

Motor

C IDU

Motor

Belt

Motor

Heat

Motor

MBF Stage

MBF Paper Empty

Duplex Unit

DUP

V71 Board

Motor

Clutch

INSENS

FSENS

RSENS

Main

14P

7P

7P

7P

7P

Front Cover

Open

Microswitch

Duplex Cover

Open Microswitch

Upper Cover

Open Microswitch

COVOPN

71K Board

POWER

FAN

FAN(LEFT)

3P

HVOLT

CPUFL1

PSIZE

DUCOV

FCOVER

DUPLEX

PARTTEMP

JODEN

RSNS

SW1

FSENS

FAN1

HUM/TMP

FAN2

CUIF

FAN4

Cord 18

Cord 19

BLACK

Exit Sns.

WHITE

REG

DCL

BELTHET

TR10P

SHUTTER

HOPFF

RCL ID

CLUTCH3

Main Motor Assy Belt Motor Assy

46

WHITE YELLOW

K LED HEAD

Control Panel

X71 board

Y LED HEAD

M LED HEAD

C LED HEAD

Toner Sensor (Y71-board)

Paper Size

Sensor

PXC-Board

AC Switch

AC

CN1 CN1

CN5

CN2

High -Voltage

Power Supply

Low-Voltage

Power Supply

CN3

CN2

16P

30P

30P

19P6P3P

16P

3P

19P

2P

8P 2P 16P

Cord 20

Cord 7

6P

TNRK

PANEL

STUCK

POWER

4P 4P

4P 4P 4P 4P

RED WHITE

BLACK YELLOW RED BLUE

6P

KPOW2

TNRY

YPOW2

TNRM

MPOW2

TNRC

CPOW2

OPTN

16P

3P

3P

3P3P3P

16P

STUCKFULL

Sns.

RED

RED

BLACK

BLACK

88

THERM1

THERM2

FUSE

NFU

3P

FAN0

Up/Down

OHP Sen.

2

RAM

CRM Board

ROM

HDD

LAN

USB

CENTRO

The C7000 Series of printers, tandem color electrophotographic page printers, adopt technologies
such as an LED array, OPC, dry single-component non-magnetic developing, roller transfer and
heat-compression fusing. A black-writing printing method by shedding light on print areas is used.

41316401TH Rev.4 12 /

Figure 2-1 provides the block diagram of the printers.

Figure 2-1

2.1 Main Board (CRM PWB)

14.31818MHz
Crystal Resonator

CY2292

CY2308Delay CDC516

SDRAM DIMM

×

4

ROM DIMM

×

3

FET SW

162212

Flash ROM

IMI530

Fluctuation Circuit

LVC244

LVC245

EEPROM

C2 LSI

MHM2031-002

PCI Bus

LAN Board

L60851

USBCentro IDE HDD

LVC161284

Buf

16244

Buf

16244

Delay

PU Board Connector, 200 Pins

to C2 LSI and

3.3V ICs

to 5V ICs

Inverter RESET-P

3.3V5V

Reset

DS1834

2.0V
Regulator

2.5V
Regulator

C1 LSI

MHM2030

-002

PPC

750

L2

Cache

Internal-CLK-

Adjusting

Resistance

80MHz

80MHz

80MHz

40MHz

80MHz

×

2

80MHz

×

16

33MHz

~

2

48MHz

IF Bus

33MHz

SPD

PU-CU I/F,

Operator Panel

A/D, Cont (SUB Bus)

Y, M, C and K Video Data

D

D

A

D

Cont

D

DD

A, Cont A, Cont A, Cont

A, Cont

A/D, Cont

Figure 2-2 provides the block diagram of the main control board (CRM PWB).

Figure 2-2

41316401TH Rev.4 13 /

(1) CPU

The CPU is PowerPC750, a 64-bit bus RISC processor, which inputs an 80-MHz CLK (= BUS
CLK), and operates at 400MHz that is five times the input.

(2) Secondary Cache SRAM

SRAM is included as secondary cache of the CPU on the board.

(3) ROM

ROM is to be inserted into the three 168 pin DIMM slots. The slot A is for program ROM and
the slot B is for Japanese kanji fonts. The slot C is not assigned.

(4) RAM

RAM is to be inserted into the four 168 pin DIMM slots. The DIMMs must be fitted in
descending labeled type No. order into the slots 1, 3, 2 and 4.

SDRAM DIMM Specifications:

Speed: PC100 or more
Capacity: 64/128/256 MB
Configuration: Without parity. Without ECC. SPD information is required. Number

of chips contained = 8 or 16.

(5) EEPROM

EEPROM, an 8-pin DIP package, is to be inserted into the IC socket. The EEPROM is of 16
Kbits for 3.3V power supply, and settings for controlling the controller block are stored in it.

(6) Flash ROM

A 2-Mbyte flash ROM is surface-mounted on the CRM board. The flash ROM is composed
of four 256-k-by-16bit chips, and fonts and macros can be stored in it.

(7) Memory Control LSI (CI)

A 696-pin BGA package ASIC made by NEC, which is equipped with a cooling heat sink and
mainly controls a CPU I/F, memory, video data compression and decompression, and a PU­video I/F.

(8) Interface Control LSI (C2)

A BGA package ASIC made by Toshiba, which controls a PU command I/F, operator panel
I/F, IDE I/F, Centronics I/F, USB I/F, PCI I/F, EEPROM and a SPD (SDRAM DIMM) I/F.

(9) IDE HDD

An IDE connector is surface-mounted on the board to which an IDE HDD assembled using
exclusive molds will be connected. The IDE HDD is used for storing font data, spooling edited
video data and registering form data.

(10) PCI Bus Option

Two PCI I/F slots are provided for option board use. The bus, which uses an Oki Data original
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

41316401TH Rev.4 14 /

2.2 Engine Controller Board (K71 PWB)

28MHz

(Color registration sensor adjustment)

Analog input

(Temperature variation)

Analog input (Transparencies)

Analog input (Various densities)

CPU BUS

Toner and ID sensors ID checks

Control Panel

Duplex

Cassette 2/3

Analog output
Analog Input

Switch

48MHz

32bit Video I/F

Heater control

Fuse Cut

Driver

EEPROM

D/A

CU I/F

CPU

MSM66Q577

A/D CON

LSI

(VIDEO MEM

Containing

4Mbit DRAM)

Fan control
Cover front/upper open

Stacker full
Test switch

(Power supply cooling)

4Kbit(512KByte)

FLASH

Interruption by motor
Interruption by UART

K Head I/F
Y Head I/F
M Head I/F
C Head I/F

Motor Driver

Motor Driver

High Voltage Power Supply

Serial Interface (2 channels)

256Kbit(32KByte)

SRAM

×

Pulse Motors

8

Paper Feed System Sensors
(Paper Feed, Paper Registration,
Write and Eject Sensors)
MT Sensor (Stage position and paper empty)
Cassette 1 Sensor
(Paper empty and near empty)
Any of Shutter, Clutch, Belt Home and
Transparency Sensors
Belt and Fuser Checks
Cassette Size

Figure 2-3

The engine control block (PU) is controlled by the engine controller board (K71 PWB) which
consists of a CPU (MSM66Q577), general LSI chip, flash ROM, EEPROM, pulse motor drivers and
a video memory (see Figure 2-4).

(1) CPU

This, a 16-bit CPU with an AD converter containing 126-Kbyte ROM (OKI MSM66Q577),
controls the entire system.

(2) General LSI

This LSI (MG63P011-001LA), which is contained in the printer engine control block, has 4
Mbits of video memory, and functions such as controller-engine video interfacing, LED
interfacing, motor control, sensor input, video memory control, main scan color misalignment
correction, skew correction and high voltage power supply control.

41316401TH Rev.4 15 /

(3) Flash ROM

The flash ROM (29F400-70) is of 4-Mbits, and PU programs are stored in it.

(4) EEPROM

The EEPROM (NM93C66N-NW) is of 4-Kbits, and mounted on the board with an IC socket.
Correction values are stored in it.

(5) Pulse Motor Driver

The pulse motor driver (A2919SLBTR, A2918SWV) drives the eight pulse motors to revolve
the EP and transport media.

(6) SRAM

This SRAM (62256LFP-7LL) is used as working memory of the CPU.

2.3 Power Units

There are a low voltage power unit consists of an AC filter circuit, low voltage power circuit and
heater driver circuit, and a high voltage power unit organizes a high voltage power circuit.

(1) Low Voltage Power Unit

This circuit generates the following voltages:

Output Voltage Use for

+3.8V CU LSI
+3.8V LED head
+5 V Logic circuit power supply, PU CPU
+34 V Motor, drive voltage and power supply voltage for high voltage power supply
+12 V OP Amp, High voltage power supply

(2) High Voltage Power Unit

This circuit generates the following voltages of not less than +34V, which are required for
electrophotographic process, according to control sequences from the controller board.

Output Voltage Use for Remark

CH -900V to 1.4KV Voltage to charging roller
DB -100 to 400V/ +300V Voltage to developing roller
SB Y, M, C and K: -100V to -700V Voltage to toner supplying roller
TR 0KV to 7KV Voltage to transfer roller Variable

41316401TH Rev.4 16 /

2.4 Mechanical Processes

Paper Eject Roller

Pape

ejection

(Face down)

Power Supply

Charging Roller

Cleaning Blade

Heat Roller

Paper

Eject

Roller

Fusing

Backup Roller

Control Signals

LED Head

Developing Roller

Power Supply

Toner Cartridge

Transfer Roller

Paper

registration

Registration

Roller 1

Paper loading

Hopping Roller

Power

Supply

Registration

Roller 2

Paper ejection Fusing Cleaning Transfer

Paper transport Paper advance

Transfer

Development

Paper Eject

Sensor

Paper Feed

Sensor 1

Paper Feed

Sensor 2

Paper Cassette

Paper

registration

(FF, 1ST, 2ND)

Write Sensor

×

4

K

YMC

Duplex printing

Paper path

selection

Paper path

selection

Paper traveling

OPC drum revolution

Charging

Exposure

Cleaning

Paper

ejection

(Face up)

Multipurpose Tray

Figure 2-4 shows the mechanical processes of the C7000 Series of printers.

41316401TH Rev.4 17 /

Figure 2-4

2.4.1 Electrophotographic process

(1) Electrophotographic process

The following is the outline of electrophotographic process:

1 Charging

DC voltage is applied to the charging roller and the surface of the OPC drum is negatively
and evenly charged.

2 Exposure

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.

3 Development

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.

4 Transfer

Placed on the surface of the OPC drum, paper is positively, or opposite to the polarity of
the toner, charged by the transfer roller on its back to transfer the toner image to the paper.

5 Cleaning

The cleaning blade removes residual toner from the OPC drum after the transfer.

6 Fusing

The toner image on the paper is fused into place through the application of heat and
pressure to it.

41316401TH Rev.4 18 /

(2) Charging

Negative DC voltage is applied to the charging roller contacting the surface of the OPC drum.

Power

unit

Charging roller

OPC drum

(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.

LED head

Power

unit

Charging roller

OPC drum

Paper

LED head

OPC drum

41316401TH Rev.4 19 /

(4) Development

By the adhesion of toner to the latent electrostatic image on the drum surface, the image is
changed to an image of its toner. The development is processed at the contact portion
between the OPC drum and the developing roller.

1 The sponge roller causes toner to adhere to the developing roller. The toner becomes

negatively charged.

Developing blade

Charging roller

Sponge roller

OPC drum

Developing roller

2 The developing blade removes excess toner from the developing roller and a thin layer

of toner remains and forms on the developing roller.

3 The 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.

41316401TH Rev.4 20 /

(5) Transfer

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.
Applying positive high voltage from the power supply to the transfer roller moves the positive
charge induced by the transfer roller to the paper surface at the contact portion between the
transfer roller and the paper, the paper surface drawing the negatively charged toner from the
drum surface.

OPC drum

Paper

Transport belt

Transfer roller

Power unit

(6) Fusing

When passing through 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 built-in upper and lower halogen lamps of 700 watts and 500 watts heat the Teflon coated
heat roller. The fusing temperature is controlled by the sum of the temperature detected by
the thermistor moving over the heat roller surface and the temperature detected by the
thermistor moving over the backup roller surface. For safety, a thermostat is provided and,
when the heat roller temperature rises by a fixed degree or more, becomes open to cut off
voltage supply to the heater. The backup roller is being pressed against the heater by the
pressure springs on both sides.

Thermostat

Thermistor

Heat roller

Paper

Thermostat

Backup roller

41316401TH Rev.4 21 /

Thermistor

(7) Cleaning

Non-fused, residual toner on the OPC drum is scraped with the cleaning blade and collected
in the waste toner area of the toner cartridge.

Waste toner area

(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.

Cleaning blade

Waste toner box

41316401TH Rev.4 22 /

2.4.2 Paper running process

Figure 2-5 shows the traveling of paper in the C7000 Series of printers.

Registration roller Assy (B)

Hopping roller

Multipurpose tray

Registration roller Assy (A)

Cleaning blade

Transfer roller ×4

Feed roller

Unit × 4

Head × 4

High voltage power supply

Face-down stacker

MYK

Belt unit

Heat roller

C

Backup roller

Cassette 1

Cassette 2

Fuser

Eject roller

Low voltage

power supply

Figure 2-5 Paper Paths

Cassette 3

41316401TH Rev.4 23 /

(1) Paper Feed from Tray

1. The running of the feed motor in the arrow direction (a) drives the feed roller and the nudger
roller. This operation feeds paper from the tray.

2. After the beginning of the paper turns the entrance cassette sensor on, the paper is
advanced a fixed length. When the paper beginning reaches the registration roller Assy
(A), the feed motor stops.

3. The running of the registration motor in the arrow direction (b), which synchronizes with
the above paper advance operation, drives the registration roller Assy (B) and the
electromagnetic clutch. The registration roller Assy (A) moves with the operation of the
electromagnetic gear when the paper beginning touches the registration roller Assy (A),
where the feed motor does not run. The feed roller idles via the built-in one-way clutch
and the nudger roller idles because the planet gear is disengaged.

4. The registration motor transports the paper until the paper end passes through the
entrance belt sensor.

Registration motor

Electromagnetic clutch

Registration roller
Assy (A)

Entrance cassette sensor

Entrance belt sensor

Registration roller

b

Assy (B)

Feed motor

a

Feed roller
(One-way clutch gear)

Paper gear

Nudger roller

Paper

Figure 2-6

41316401TH Rev.4 24 /

(2) Paper Feed from Multipurpose Tray (MT)

1. The release lever usually pushes down the hopping plate to a position that turns
microswitch on (Figure 2-7-a).

2. The running of the motor in the (a) direction drives the MT feed roller and turns the cam.
The cam pushes the release lever and the hopping plate picks up paper sent out by the
MT feed roller (Figure 2-7-b), where the registration roller Assy (B) does not move because
its one-way clutch gear (1) idles.

3. After the paper beginning turns the entrance sensor on, the paper is forwarded a fixed
length. The paper stops when its beginning reaches the registration roller Assy (B).

4. At the same time, the cam pushes down the hopping plate. The release lever that has been
placed in its original position by the spring locks the hopping plate (Figure 2-7-c).

5. After the completion of the paper feed operation, the registration motor runs in the arrow
direction (b) to drive the registration roller Assy (B), where the one-way clutch gear (2)
does not allow the MT feed roller to move.

One-way clutch gear (2)

MT feed roller

Entrance sensor

Paper

Entrance belt sensor

Registration motor

Release lever

Spring

b

a

Registration roller Assy (B)

One-way clutch gear (1)

Figure 2-7

Hopper plate

Feed roller

Microswitch

Figure 2-7-a Figure2-7-b Figure 2-7-c

41316401TH Rev.4 25 /

(3) Transport Belt

1. The running of the transport belt motor in the arrow direction (a) drives the transport belt.
The belt unit sits with one transport roller immediately below each color’s drum, and the
transport belt between them. By the application of a fixed voltage, the transport belt and
the transport roller feed paper on the transport belt into the fuser unit, transferring a toner
image on each color’s drum.

Drum

Transport belt

KYMC

Transport (transfer) roller

Transport (transfer) belt motor

Figure 2-8

41316401TH Rev.4 26 /

(4) Driving and Up-and-Down Movements of I/D Unit

1. The I/D unit driving and up-and-down movements are effected by a single-pulse motor.
The running of the main motor in the arrow direction (a) turns the lever 1 to the left. Then,
the lever 2 that was lifted by the lever 1 lowers to move down the I/D unit. After the up/
down sensor is turned off (Figure 2-9-d), specified downward pulsing places the I/D unit
in its lowest position, or equivalently, printing position (Figures 2-9-a and 2-9-c).
The drum gear engages with the driving gear and starts revolving to transfer an image on
the drum to running paper, where the one-way gear idles upon placement of the lever in
its lowest position.

2. With the running of the main motor in the arrow direction (b), the lever 1 pushes up the I/
D unit via the lever 2. After the up/down sensor is activated (Figure 2-9-d), the lever 1 lifts
the I/D unit to a specified level and stops to keep space to an extent between the drum and
the transport belt (Figures 2-9-c and 2-9-e).
The drum gear is not engaged with the driving gear and does not revolve.

3. When the two pins of the up/down sensor are pushed up by the I/D unit, and touches and
electrically connected to the plate above the pins, the sensor recognizes the on state.
When the two pins are pushed down by the I/D unit, and separated and insulated from the
plate, the sensor recognizes the off state.
The installation of the I/D unit can also be verified by recognizing the off state of the up/
down sensor.

Lever 2

Driving gear

I/D unit

a

Drum

One-way gear

Lever 1

b

Figure 2-9-a Figure 2-9-b

41316401TH Rev.4 27 /

Plate

Pin Spring

Board

Up/down sensor

Figure 2-9-c

Figure 2-9-d

Figure 2-9-e

41316401TH Rev.4 28 /

(5) Fuser Unit and Paper Ejection

1. A single-pulse motor drives the fuser unit and the eject rollers.
In response to the running of the heat motor in the arrow direction (a), the heat roller turns.
This roller fuses a toner image to paper by heat and pressure.

2. At the same time, the four eject rollers move to eject the paper.

3. The ejection path is switched back and forth between the route to the face-up stacker and
the route to the face-down stacker as follows. When the face-up stacker opens, the paper
separator inclines in the direction that guides the paper to the face-up stacker. When the
face-up stacker closes, the paper separator inclines in the direction that sends the paper
to the face-up stacker.

Eject rollers

Fuser unit

Heater motor

Heat rollers

a

Figure 2-10

Paper separator

Face-up stacker

41316401TH Rev.4 29 /

(6) Duplex Unit

1. When the duplex unit receives an instruction from the printer to print on both sides of a
sheet of paper, the solenoid opens the separator after the completion of one side printing
of a sheet of paper sent from the tray. The path is switched to that to the duplex unit.
At this time, as the roller (1) turns in the direction of the arrow “a,” the paper is retracted
on the rear of the cassette.

2. When fixed time has elapsed after the paper beginning passes through the duplex-in
sensor, the rollers reverse and the roller (1) turns in the direction of the arrow “b” to feed
the paper into the duplex unit. After that, the paper passes through the rollers (2), (3) and
(4), and ejected with the other side printed, and fed again into the printer.

Separator

Figure 2-11

Solenoid
Duplex-in sensor

b

a

Motor

Roller(2)Roller(3)Roller(4)

Roller(1)

41316401TH Rev.4 30 /