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Service Guide - OKICOLOR8
Chapter 0 Introduction

Page: 1

Front Cover

Service Guide
OKICOLOR 8 & OKICOLOR 8n Digital LED Page Printers
Adobe Acrobat printable reference copy of the OKIDATA Service Training Manual. 12/20/99

Note: This Adobe Acrobat version of the Okidata Service Training Manual was built with the pictures rendered at 72 dpi, which is ideal for screen viewing. For future updates to this manual, and more on-line information visit our Business Partner Exchange (BPX) at http://bpx.okidata.com.
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Table of Contents

Page

Service Guide - OKICOLOR8
0 Introduction ....Preface 1 Specifications 1.1 Basic System Configuration 1.2 Printer Specifications 1.3 Option Specifications 1.4 Basic Specifications 2 Operation 2. Operation 2.1 Main Control Board (PCE PCB) 2.2 Engine Control Board (PX4 PCB) 2.3 Power/Board 2.4 Mechanical Processes ....2.4.1 Electrophotographic processing mechanism ....2.4.2 Paper running process 2.5 Sensors ....2.5.1 Paper Related Sensors ....2.5.2 Other sensors 2.6 Correction of Color Deviation 2.7 Transfer Control according to Environmental Changes 2.8 Form Jam Detection 2.9 Cover Opening 2.10 Toner Lower Detection 2.11 Page Size Detection 2.12 Power-on Processing 3 Disassembly 3.0 Parts Replacement 3.1 Precautions for Parts Replacement 3.2 Parts Layout 3.3 How to Change Parts ....3.3.1 Cover Assy Rear ....3.3.2 Motor-Fan (80-25) ....3.3.3 Paper Eject Assy ....3.3.4 Cover Assy Stacker, Guide Eject FD Assy ....3.3.5 Upper Frame Assy ....3.3.6 Plate Support Assemblies ....3.3.7 Limiter 2way (L), (R) / Plate Guide (L), (R) ....3.3.8 Cover ....3.3.9 PCE PCB Assy ....3.3.10 Motor Fan (CU) ....3.3.11 PXF PCB / PX4 PCB ....3.3.12 Gear Heat Assy ....3.3.13 Main Motor (A), (B) Assy ....3.3.14 Gear One-way (Z30) ....3.3.15 Motor Assy Belt ....3.3.16 Power Supply Unit, Holder Inlet, Sheet Insulation ....3.3.17 Sensor Assy Box Toner ....3.3.18 Square-shaped Connector ....3.3.19 Motor - Pulse (ID) ....3.3.20 One-way Gears

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

Table of Contents

Page

....3.3.21 Feeder Unit Front ....3.3.22 Manual Feed Hopper Assy ....3.3.23 Guide Paper Input Assy ....3.3.24 Two Lever Input Sensors, Lever 2nd Feed Sensor ....3.3.25 Roller Registration, Roller Assy Hopping ....3.3.26 Hopping Roller Assy ....3.3.27 PXU PCB/PXM PCB, Lever Resist Sensor ....3.3.28 Paper End Lever ....3.3.29 PCO PCB (Operator Panel) ....3.3.30 Holder Gear Toner Assy ....3.3.31 Plate Latch Lever (FD), Spring Latch Lever (FD) ....3.3.32 Transfer Belt ....3.3.33 High Voltage Power Supply Unit, Bracket HV (BT) Assy ....3.3.34 Eraser Bracket Assy, Eraser Bracket (KCM) Assy ....3.3.35 Shaft Link ....3.3.36 Contact Bracket (BL-R) Assy, Contact Bracket (CL-R) Assy ....3.3.37 Contact (BL-L) Assy, Contact (CL-L) Assy ....3.3.38 Contact SB Assy ....3.3.39 PXC PCB ....3.3.40 Heat Unit Assy (Fuser unit and oil roller) ....3.3.41 Oil Roller Kit ....3.3.42 Lever Lock Heat (L)/(R), Guide Side Heat, Spring Lock ....3.3.43 PXL PCB ....3.3.44 Heat Unit Guide Assy ....3.3.45 Holder LED Assy, LED Head 4 Adjustments 4. Adjustments 4.1 Maintenance Modes and Their Functions ....4.1.1 User maintenance mode ....4.1.2 System maintenance mode ....4.1.3 Engine maintenance mode 4.2 Adjustments after Parts Replacement ....4.2.1 Confirm the LED head driving time ....4.2.2 Color Registration Using the Operator Panel (Color deviation correction) 5 Maintenance Periodic Maintenance ....5.1 Periodically Replaced Parts ....5.2 Cleaning ....5.3 Cleaning the LED Lens Array ....5.4 Cleaning the Pickup Roller 6 Troubleshooting Procedures 6.0 Troubleshooting Procedures ....6.1 Troubleshooting Tips ....6.2 Points to Check before Correcting Image Problems ....6.3 Tips for Correcting Image Problems ....6.4 Preparation for Troubleshooting ....6.5 Troubleshooting Flow

48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80

81 82 83 84 84 85 86 87 87 88 89

Table of Contents

Page

........6.5.1 LCD status message/trouble list ........6.5.2 LCD message troubleshooting ............(1) The printer does not work normally after turned on. ............(2) JAM ERROR ............(3) Paper Size Error ............(4) Image Drum Unit (IDU) Up/Down Error ............(5) Fusing Unit Error ............(6) Fan Motor Error ............(7) Cannot Receive Data from Parallel Interface ........6.5.3 Image Troubleshooting ............(1) Light or blurred images on the whole printout area ............(2) Dark background ............Printout colors different from original colors ............(3) Blank paper ............(4) Vertical black (black stripe or lines in the vertical direction) ............(5) Vertical white (White stripe or lines in the vertical direction) ............(6) Poor fusing (Images are blurred or peeled off when touched) ............(7) Evenly spaced, repeating marks (Cyclical printout defects) ............(8) Missing characters or colors ............(9) Poor synthesization Color ............(10) Printout colors diferent from original colors 7 Wiring Diagram 7.1 Resistance Check 7.2 Program/Font ROM Location 8 Illustrated Parts List Figure 8-1: Covers (Top & Sides) Figure 8-2: Printer Unit Figure 8-3: Main Chassis Unit (1) Figure 8-4: Main Chassis Unit (2) Figure 8-5: Main Chassis Motor/PCB Figure 8-6: Frame Upper Assy Figure 8-7: Guide Cassette (R) Assy Figure 8-8: Main Motor (A) Assy Figure 8-9: Main Motor (B) Assy A Centronics Parallel Interface Centronics Parallel Interface

90 91 91 91 91 91 91 91 91 92 92 92 93 94 95 96 97 98 99 99 100 101 102 102 102 102 102 102 102 102 102 102

Service Guide - OKICOLOR8
Chapter 0 Introduction

Page: 1

Preface

This manual provides procedures and techniques for the troubleshooting, maintenance, and repair of OKICOLOR8. This manual is written for maintenance personnel, but it should always be accompanied with the OKICOLOR8 User's Manual for procedures for handling and operating OKICOLOR8. For repairing each component of OKICOLOR8, see the Troubleshooting Manual.
[Notices]

The contents of this manual are subject to change without prior notice. Although reasonable efforts have been taken in 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 OKICOLOR8 in any manner.
[Warning]

Many parts of OKICOLOR8 are very sensitive and can be easily damaged by improper servicing. We strongly suggest that OKICOLOR8 be serviced by OKI's authorized technical service engineers.
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 1 Specifications

Page: 2

1.1 Basic System Configuration

This diagram shows the basic system configuration of OKICOLOR 8 is illustrated in Figure 1.1 below.

Figure 1.1

< same diagram -- different view >

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 1 Specifications

Page: 3

1.2 Printer Specifications

This printer unit is composed of the following hardware.
l l l l l

Electro-photographic processor Paper feeder Controller (CU part / PU Part) Operator panel Power board (High voltage part / PU part)

This diagrams shows the printer unit configuration.

Figure 1.2
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 1 Specifications

Page: 4

1.3 Option Specifications

The OKICOLOR8 options are listed below. (1) Second Paper Feeder

(2) RAM SIMM module (72 pin SIMM, 4MB/8MB/16MB/32MB)
l

Make sure to use a set of 2 of the same volume size modules.

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 1 Specifications

Page: 5

1.4 Basic Specifications (1) (2) (3) Dimensions Weight Form

Width: 18.8" Length: 24.5" Height: 15.6" Approx. 106 lbs. without box
Type: Ordinary paper (Hammermill xx lb.) and Transparency (Only 3M CG3710)

(4) (5) (6) (7) (8) (9) (10)

(11)

Recommended paper (for color printing) Color laser paper (20 lb to 24 lbs.) Note: the printout color tones are dependent upon the whiteness of the print paper. Sizes: Letter, Legal (13" or 14"), Executive, A4, A5, B5, and B6 (1st tray and front feeder) Reams: 1st tray - 20 lbs. to 28 lbs. 2nd tray - 20 lbs. to 28 lbs. Front feeder - 20 lbs. to 53 lbs. (110 lbs. index) Printing speed: 8 pages per minute (5 pages per minute: Card Stock, Labels & OHP / 34 lbs. ~ 44 lbs.) Resolution 600 dots per inch x 600 dots per inch Input voltage 120VAC +5.5%, -15% 230VAC +10% Power consumption Peak: Typical operation Idle: Power save mode Frequency 50Hz or 60Hz +2%, -2% Noises Operating: 54 decibels (without 2nd tray), 55 decibels (with 2nd tray) Standby: 45 decibels Power-saving: 43 decibels Expendables and Toner Cartridge: Approx. 3000 pages (5% density) (each of C, M, Y, and K) service life Image Drum: Up to 13,000 pages (5% density, continuous) (each of C, M, Y and K) Waste Toner Box: Up to 25,000 sheets (under typical printout conditions: Single images of 5% density, equivalent to printout using 14 toner cartridges) Oil Roller Unit: Up to 10,000 sheets (Life defined in the number of actual printed paper sheets) Note: Y=Yellow, M=Magenta, C=Cyan, K=Black Periodically Fuser Heat Unit Assy: 60,000 pages replaced parts Transfer Belt Cassette Assy: 50,000 pages

(12) Temperatures and relative humidities Temperature Fahrenheit Temperature conditions Celsius Remarks

Operating Non-operating Storage (1 year max.) Delivery (1 month max.) Delivery (1 month max.)
Humidity

60.8 to 89.6 50 to 109.4 -33 to 109.4 -20 to 122 -20 to 122

16 to 32 10 to 43 -.6 to 43 -29 to 50 -29 to 50

17 Celsius to 27 Celsius (for assurance of full-color printout quality) Power off with drum and toner without drum and toner and Belt Cassette Assy with drum and toner

Fahrenheit

Humidity condition Celsius Remarks

Operating Non-operating Storage Delivery

20 to 80 10 to 90 10 to 90 10 to 90

25 26.8 35 40

50% to 70% (for assurance of full-color printout quality) Power off

(13) Printer life - 300,000 (A4) pages or 5 years
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 6

2. Operation

OKICOLOR8 is a tandem color electrophotographic page printer, using 4992 Pixel-LED technologies, OPC, dry single-component non-magnetic developing, roller transfer, heat-compression fixing (fusing). The printing method used is a Black Writing method which applies light beams to printout areas. Here is the Functional Block Diagram of OKICOLOR8.

Figure 2.1 < same diagram - side view >

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 7

2.1 Main Control Board (PCE PCB)

The control board consists of a CPU block, a memory control LSI block, an interface control LSI block, a DRAM block, an EEPROM block, a mask ROM block, and an interface block. Here is the Functional Block Diagram of the main control board (PCE PCB).

Functional Block Diagram of Main Control Board (1) (2) CPU

The CPU is a 64-bit RISC architecture processor (provided by NEC). It inputs a frequency of 50 MHz and runs at 200 MHz. It transfers data to a from memory at 50 MHz.
Mask ROM

The mask ROM block consists of four 16 Mbit (1M x 16 bits) chips and its total size is 8M bytes. The chips are mounted on the PCE-PCB by means of IC sockets and store programs and character fonts.
(3) DRAM

The DRAM block consists of eight 16 Mbit (1M x 16bits) chips and its total size is 16M bytes. The chips are mounted on the PCE-PCB and can be expanded up to 144M bytes by adding the 32M byte SIMMs to the SIMM slots on the PCE-PCB.
(4) EEPROM

The EEPROM block consists of 16K-bit chips mounted on a board by means of IC sockets and stores the following: l Menu data l Counter values l Adjustment values
(5) (6) (7) Flash ROM

The Flash ROM block consists of four 4M bit (256K x 16bits) chips and its total size is 2M bytes. The chips are mounted on the PCE-PCB and are used for storing fonts, macro and demo pages.
Memory control LSI

This block mainly consists of memory control, CPU control, compression and decompression, and video interface functions.
Interface control LSI

This block mainly consists of PU interface control, operator panel interface control, EEPROM control, parallel interface control, and HSP control functions.

(8)

Host interface

The printer has the following interfaces to the host.
l l

Centronics bi-directional parallel interface Network interface (Option)

The single effective interface or the automatic interface select mode can be selected using the menu. If the busy state of the printer continues for a long time period, the buffer near-full control releases the busy status at constant intervals even if the host side is busy so as not to cause interface time-out at the host side. (a) Centronics bi-directional parallel interface This is an interface confirming to IEEE-1284 and provides either unidirectional ad bi-directional communications according to each of the following communication modes.
l l

Compatibility mode - Unidirectional communications from the host to the printer. Nibble mode - This mode transfers 4-bit wide data from the printer to the host. In this mode,

l

each bit of 1-byte data transmits in the form of two nibbles using ERROR, BUSY, FAULT, and SELECT signal leads. This mode can provide bi-directional operation in combination with the compatibility mode. ECP mode - This mode provides the asynchronous bi-directional interface and transmits and receives 1-byte data using eight data signal leads under semi-duplex control by the host.

When the power is turned on, the compatibility mode is automatically selected. The change to another mode form the compatibility mode is made through negotiation. (When the BI-DIRECTION is set to ENABLE in the menu, this change can be performed.) (For the electrical/physical characteristics of this interface, see APPENDIX B). (b) Network interface (Option) Network interface card uses the power line only.

(9)

This printer has the 2nd Cache unit which type is Write Through Cache and size is 512 KByte. There are any difference between the instruction and data. All of the CPU read/write access are cached to same 2nd cache memory.

(10)

RAM module
l

Pin layout

l

Basic specification Type: Access time: Capacity: Parity:

72 pins SIMM (32 bits buss width) 60ns, 70ns, 80ns 4, 8, 16, or 32 None

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 8

2.2 Engine Control Board (PX4 PCB) ANALOG INPUT (Heater temperatures and environmental humidity and temperature)

Engine Control Board Block Diagram

The engine control block (PU) is controlled by the engine control board (PX4 PCB) which consists of a CPU (MSM65524), general purpose LSI chips, EPROM, EEPROM, pulse motor drivers, and video memory. Refer to the Engine Control Board Block Diagram above.

(1) (2)

CPU

This is an 8-bit CPU (OKI MSM65524) containing the AD converter and controls the whole system.
General-purpose LSI

This LSI (MB87D113PFV) is provided in the printer engine control block and has controller-engine video interface, LED interface, motor control, sensor input, video memory control, main scanning color correction, skew correction, high-voltage power control, and OST-EX2 functions.
(3) (4) (5) (6) EPROM

This EPROM (275C512-150) has a storage capacity of 512K bits and stores programs for the PU block.
EEPROM

This EEPROM (NM93C66N-NW) has a storage capacity of 4K bits. It is mounted on the board by means of IC socket and stores adjustment values.
Pulse motor drivers

These drivers (MTD2005F) drive eight pulse motors for moving up and down the image drum (EP) and transferring medium.
Video memory

This SRAM received print data through video interface and stores it.
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 9

2.3 Power/Board

The power board consists of an AC filter circuit, a low voltage power supply circuit, a high voltage power supply circuit, and heater drive circuit, and photo sensors.
(1) Low voltage power supply circuit.

This circuit generates the following voltages.
Output voltage Use

+3.3 V +5 V +32 V +12 V -12 V

CU Unit CPU, LED HEAD Logic circuit supply voltage Motor and fan drive voltage and source voltage for high-voltage supply, discharge lamp HSP, OP Amp, high voltage power supply HSP

(2) High voltage power supply circuit

This circuit generates the following voltages necessary for electro-photographic processing from +32 V in accordance with the control sequence from the control board. When cover open state is detected, +32 V supply is automatically interrupted to stop the supply of all high-voltage outputs.
Y M C K = Yellow, Magenta, Cyan, Black Output Voltage Use Remarks

CH DB

-1.35 KV ±50V Normal paper Y.M.C.K.: -250V/+300V, -232V/+300V (First paper: Y only) K.: -270V/+300V Transparency Y.M.C.: -200V/+300V, K.: -250V/+300V Y.M.C.K.: -650V/0V 0 to 4 KV 0 to 2.5 KV

Voltage applied to charging roller Voltage applied to developing roller

SB TR FIX

Voltage applied to toner supply roller Voltage applied to transfer Variable roller Voltage applied to transfer Variable roller

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 10

2.4 Mechanical Processes

Here is the Mechanical Process Diagram of OKICOLOR8.

Mechanical Process Diagram (Figure 2.5) 2.4.1 Electrophotographic processing mechanism 2.4.2 Paper running process

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 11

2.4.1 Electrophotographic processing mechanism (1) Electrophotographic processes - Each process of the electrophotographic processing mechanism

is outlined below. (1) Paper pickup - This process causes the roller to give a DC voltage to the paper, resulting in a negative charge. With this negative charge, the paper is electrostatically attracted to the roller. (2) Charging - This process gives a DC voltage to the charge roller so that the image drum may have a uniform negative charge on its surface. (3) Exposure - This process causes the LED head to apply light beams according to image signals to the negatively-charged surface of the image drum. The negative charge on the illuminated surface of the image drum is reduced according to magnitudes of the light beams. Thus, a latent image is formed on the surface of the image drum according to the resulting surface potentials. (4) Developing and recovery of excessive toner - This process applies negatively-charged toner to the surface of the image drum. The toner is electrostatically attracted to the latent image to form a visible image on the surface of the image drum. Simultaneously, this process electrostatically transfers excessive toner from the image drum to the developing roller. (5) Transferring - This process fits paper to the surface of the image drum and applies positive charge (opposite to the charge of the toner) to the back side of the paper from the transfer roller. The toner image is transferred to the paper. (6) Cleaning - Cleaning blade scrapes off the remaining toner of any image drum, which has been used to transfer the image drum the drum to the paper. (7) Fixing - This process fixes the toner image on the paper by pressing the fusing the image.
(2) Paper pickup

A DC voltage (0V to 2KV) is applied to the driven roller A, to create a positive charge on the lower surface of the paper. The kept in charged paper is electrostatically attracted to the pickup roller. The paper is in close contact with the conveying Belt and moves steadily.
(3) Charging - This process applies a DC voltage to the charging roller in contact with the surface of the image drum.

(4) Exposure - The light beams from the LED head are applied to the surface of the image drum which is charged negatively. The negative charge on the illuminated surface f the image drum is reduced according to the magnitude of the light beams and a latent image is formed on the surface of the image drum according to the resulting surface potentials.

(5) Developing - This process applies toner to the latent image on the surface of the drum to create a toner image.

Developing is carried out on the surface of the image drum at where the image contacts with the developing roller.
(1) The sponge roller transfers toner to the developing roller. The toner is charged negatively.

(2) The toner blade scrapes away excess toner from the developing roller, leaving a thin film of toner on the

surface of the developing roller.
(3) The toner is attracted to the latent image on the surface of the image drum, where the image drum contacts

the developing roller. The latent image on the surface of the image drum is made visible with the toner.
(6) Transferring - The transfer roller made of conductive sponge presses the paper against the surface of the image

drum. The paper will make close contact with the surface of the image drum. This process fits the paper to the surface of the image drum (using the transfer roller) and applies a positive charge (opposite to the charge of the toner) from under the paper. When a positive high voltage is applied to the transfer roller from the power supply, the positive charge induced on the transfer roller jumps to the upper surface of the paper (where the transfer roller touches the paper) and attracts the negatively-charged toner from the surface of the image drum onto the surface of the paper.

(7) Fixing - The toner image just transferred to the paper is fused and fixed to the paper while the paper is passing

through the gap between the heat roller and the backup roller. The teflon-coated surface of the heat roller is heated by the 800-watt heater (or a halogen lamp) in the heat roller. The temperature of the heat roller surface is controlled by a thermistor in contact with the surface of the heat roller. A thermostat is provided for safety. When the heat roller temperature rises above the preset temperature, the thermostat opens and shuts off power to the heater in the heat roller. The backup roller is evenly pushed against the heat roller by two end springs.

(8) Cleaning - The toner which remains on the (OPC) Image Drum without being fused is scraped by a cleaning

blade and discarded in the waste toner tank.

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 12

2.4.2 Paper running process

How paper moves through the OKICOLOR8 is shown in the Paper Route Diagram.
Y=Yellow; M=Magenta; C=Cyan; K=Black

(1) Paper hopping and transfer and up/down movement of pinch roller 2

Paper is hopped and delivered by the mechanism shown below. This mechanism is driven by a single pulse motor.

The pulse motor turns in the arrow direction (a) and drives the hopping roller in the direction of "b". The hopping roller drives the resist roller. Gears A, B, and C, have one-way clutches to prevent the roller form rotating reversely.
a) Hopping

(1) The pulse motor turns in the arrow direction of "a" (counterclockwise) and drives the hopping roller to move the paper until the Entrance sensor turns on. Although the one-way gears B and C are driven, the resist roller 2 does no turn. The reverse rotations of the one-way clutch gears are not transmitted to the resist roller. (2) After the Entrance sensor turns on, the hopping roller keeps on feeding the paper until it hits the resist roller 1. This operation corrections any paper skew.

b) Conveying

(1) After paper hopping is completed, the pulse motor turns right (in the direction of "b") to drive the resist rollers 1 and 2. The resist rollers feed the paper until the Form sensor turns on. Although the one-way gear A is also driven, the hopping roller does not turn because of the one-way clutch. (2) The paper is further fed in synchronism with the print data.

(2) The hopping operation of the front feeder and the up/down operation of the pinch roller 2 are performed by a single pulse motor.

When the pulse motor of the front feeder turns right (in the direction of "A"), the front hopping roller turns left (in the direction of "b") to drive the cam. This cam moves up an down the pinch roller 2. The one-way clutch gears are made to turn only in a present direction by means of the one-way clutches.
(a) First and second hopping rollers 1 When the front edge of the paper passes by the pickup roller, the pulse motor of the front feeder turns

counter-clockwise (in the direction of "b" to drive the cam. The cam moves up the pinch roller 2. Although the one-way clutch gear A is also rotating, the hopping roller of the front feeder does not rotate (because of the one-way clutch).
2 When the rear edge of the paper passes by the Entrance sensor 2, the pulse motor of the front feeder turns counter-clockwise (in the direction of "b") to drive the cam. The cam moves down the pinch roller 2 until it is sensed by the sensor. Although the one-way clutch gear A is also rotating, the hopping roller of the front feeder does not rotate (because of the one-way clutch).

(b) Front feeding hopping

(1) The pulse motor of the front feeder turns right (in the direction of "a") to drive the hopping roller. The paper feeds until the Entrance sensor 2 is activated. Although the one-way clutch gear B is also rotating, the pinch roller 2 does not drive the up/down cam (because of the one-way clutch). After the Entrance sensor is activated, the paper feeds until it reaches the resist roller. (2) This operation corrects any paper skew.

(c) Conveying

(1) After paper hopping is completed, the pulse motor turns right (in the direction of "b") to drive the resist rollers 1 and 2. The resist rollers feed the paper until the Form sensor turns on. (2) Although the one-way gear A is also driven, the first hoping roller does not turn (because of the one-way clutch).

(2) Up/down movement of the image drum unit and rotation of the image drum.

The up/down movement of the image drum unit and the rotation of the image drum are performed by a mechanism shown below. (See Figure 2.6-a). This mechanism is driven by a single pulse motor. When the pulse motor turns left (Counter-clockwise), the up/down gear turns left (in the direction of "a"), and the up/down lever (see Figure 2.6-b) moves up (in the direction of "a". The up/down lever pushes up the up/down actuator of the image drum unit. The image drum unit moves up as shown in Figure 2.6-b). The image drum rotates freely.

When the pulse motor (see Figure 2.6-a) turns right (Counter-clockwise), the image drum gear turns left (Counter-clockwise) and the up/down gear (one-way gear) is released. The weight of the image drum unit is applied to the up/down lever via the up/down actuator of the image drum unit. The free up/down gear turns right (in the direction "b" in Figure 2.6-a), and the image drum unit goes down until the up/down actuator of the image drum unit is stopped by the up/down lever. (See Figure 2.6-c). During this, the image is transferred onto the running paper.

(3) Lubrication and cleaning of fixing, ejecting, and heat rollers.

The fixing roller, the ejecting roller, and the heat roller are lubricated and cleaned by a single pulse motor. When the heat roller pulse motor turns right (in the direction of "a"), the heat roller and the backup roller turn left (in the direction of "a") to fix a toner image onto the paper. At the same time, three ejection rollers turn right (in the direction of "a") to eject the paper. The oil roller and the oil cleaning roller turn left (in the direction of "a") to supply oil to the surface of the heat roller and clean the surface.
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 13

2.5 Sensors 2.5.1 Paper related sensors 2.5.2 Other sensors
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 14

2.5.1 Paper Related Sensors

Sensor

Function

Sensor status

FF sensor 1/2 (Entrance sensor 1/2) Write sensor

Detects the front edge of an incoming paper and determines timing to change from hopping to conveying. Detects the front edge of the conveyed paper sheet and determines the length of the paper sheet from elapsed time before the front edge of the paper reaches the sensor. Detects the front and rear edges of a paper sheet and determines whether the paper is ejected.

ON: Front edge detected OFF: Front edge not detected ON: Form present OFF: Form absent

Ejection sensor

ON: Form present OFF: Form ejected

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 15

2.5.2 Other sensors (1) (2) (3) (4) Form end sensor

This sensor checks whether the paper cassette is empty.
Front Feeder form end sensor

This sensor checks whether the front feeder has paper.
Front Feeder home switch

The microswitch checks whether the front feeder stage is in the up or down position.
Image Drum

Image drum up/down sensor (one for each color C, M, Y, K) C = Cyan, M = Magenta, Y = Yellow, K = Black
(5) Waste toner sensor

This sensor judges whether the waste toner cartridge is full by measuring a time period at which the sensor lever turns on periodically. When the time period falls under a preset value, the system judges that the waste toner cartridge is full and displays the "waste toner full" message.
(6) (7) (8) Resist up/down sensor

This sensor detects the up or down position of the resist roller 2.
Temperature sensor

Refer to 2.7 (Transfer Control according to Environmental Changes)
Humidity sensor

Refer to 2.7 (Transfer Control according to Environmental Changes)
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 16

2.6 Correction of Color Deviation

OKICOLOR8 is equipped with an array of I/D units which cannot be from generation of color deviations. This mechanically caused color deviation is corrected electronically as shown below.
(1) Color deviations to be corrected

1 Color deviation in the X axis (Positional error of the LED head) 2 Diagonal color deviation (Positional error of the LED head) 3 Color deviation in the Y axis (Positional errors of the I/D units and light receivers)
(2) Method of correction Print out the preset color chart, compare the printed color chart by the original color chart,

and enter the amount of color deviation of each color from the operator panel or from the host computer. OKICOLOR8 calculates correction values from the entered values and changes the write timing of each color (cyan, magenta, and yellow) relative to black.
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Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 17

2.7 Transfer Control according to Environmental Changes

Transfer Control according to Environmental Changes (Room Temperatures and Relative Humidities) OKICOLOR8 measures the room temperature and humidity. It uses a room temperature sensor and a room humidity sensor. An optimum transfer voltage is calculated, using the obtained environmental conditions. The unit then prints, using the optimum transfer voltage.
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 18

2.8 Form Jam Detection

OKICOLOR8 checks for a paper jam when the page printer is powered on, and during printing. When a paper jam is found, the OKICOLOR8 immediately stops the printing process. To recover the printer, open the cover, find and remove the jammed paper, then close the cover.
Error Form feed jam Convey jam Ejection jam Form size error Conditions

Three hopping operations are made, but the Form Feed sensor (Entrance) does not turn on within a preset time after the Form Feed sensor 1 turns on. The ejection sensor does not turn on within a preset time period after the Write sensor detects the front end of paper. The eject sensor detected the front edge of the paper, but does not detect the rear edge of the paper within a preset time period. The form size (obtained by measuring the time period between the rear edge of the paper passes by the Form Feed sensor 2 after the front edge of the paper passed the Write sensor) is longer by 45mm than the specified form length.

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Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 19

2.9 Cover Opening

When the upper, side, or front cover of the OKICOLOR8 is opened, the Cover open microswitch turns off, the voltage of 32V to the high-voltage power supply is shut off, and all high-voltage outputs are shut off. At the same time, the CPU receives a signal (CVOPN), (indicating the status of the microswitch), and performs the cover open process.

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Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 20

2.10 Toner Lower Detection
l

Composition

The device consists of the stirring gear (which rotates at a constant rate), the stirring bar, and the magnet on the stirring bar. The stirring bar rotates by engaging with the concave section in the stirring gear.

l

Operation

Toner Low is detected by monitoring the time interval between engagement of the magnet set on the sensor lever and the magnet on the stirring bar.
OPERATION during toner full state
l

The stirring bar rotates by interlocking with the stirring gear. l When the magnet on the stirring bar reaches its maximum height, the other end of the bar is dipped in the toner. The stirring bar is pushed by the stirring gear.

Operation during toner low state
l

When the stirring bar reaches the maximum height, the lack of toner provides no resistance on the other end. The bar falls to the minimum height, due to its own weight. l The time length of the encounter (between the stirring bar magnet and the sensor lever magnet), counter with the magnet of the sensor lever becomes long. By monitoring this time interval, toner low is detected.

l l l l

When the toner low state is detected 2 times consecutively, Toner Low is established. When the toner full state is detected 2 times consecutively, Toner Low is canceled. When there is no change with the toner sensor for 2 cycles (1.965 sec. x 2) or more, the Toner Sensor Alarm is activated. The toner sensor is not monitored while the drum motor is in halt.
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Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 21

2.11 Page Size Detection

The four tab pieces are driven according to the setting position of the paper guide (through the cam interlocked with the paper guide of the paper cassette). When the paper cassette is inserted into the printer, the position of the tab pieces is detected by a microswitch, recognizing the paper size.
STATE OF MICROSWITCHES SW1 SW2 SW3 SW4 Paper size

0 0 0 1 1 1 1 1

1 1 0 1 0 1 1 0

1 0 1 1 1 0 0 0

1 1 1 0 1 1 0 1

Letter Executive A4 Legal 14 Legal 13 B5 A5 A6

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Service Guide - OKICOLOR8
Chapter 2 Operation

Page: 22

2.12 Power-on Processing 2.12.1 Self-diagnostic test (1) Initial test

The following check are automatically performed when the printer is power on: (a) ROM check (b) RAM check (c) EEPROM check (d) Flash ROM check
(2) ROM check

(a) Checks ROM by comparing the sum of bits in the received data unit by the number of bits in the transferred data unit.
(3) RAM check

(a) Checks RAM by writing a preset data patter in RAM, reading the contents of RAM, and comparing the data read from RAM by the data written in RAM. (Write-read test). (b) Checks optional RAM (if it is installed). (c) Checks resident RAM by exclusively O Ring high and low addresses (to prepare 16-bit data units), writing a preset 16-bit data patter in RAM, reading the contents of RAM, and comparing the data read from RAM by the data written in RAM. Checks optional RAM by writing and reading 32-bit fixed patterns ("5555h" and "aaaah") in optional RAM.
(4) EEPROM check

(a) Checks identification numbers stored in the fixed addresses of EEPROM. (b) Checks the contents of the menu area (by control firmware) and the engine area (by engine firmware).
(5) Flash ROM check

Checks Flash ROM by writing a present data pattern in Flash ROM, reading the contents of Flash ROM, and comparing the data read from Flash ROM by the data written in Flash ROM. (Write-read test).
(6) Option check unit

Checks whether the optional units (such as the second tray, and PS SIMM) have been installed before entering the operation mode.

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 23

3.0 Parts Replacement 3.1 Precautions for Parts Replacement 3.2 Parts Layout 3.3 How to Change Parts

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 24

3.1 Precautions for Parts Replacement (1) Before starting parts replacement, remove the AC cable and interface cable. (a) Removing the AC cable

i) Turn off ("o") the power switch of the printer. ii) Disconnect the AC inlet plug of the AC cable from the AC receptacle. iii) Disconnect the AC cable and interface cable from the printer.
(b) Reconnecting the AC cable

i) Connect the AC cable and interface cable to the printer. ii) Connect the AC inlet plug to the AC receptacle. iii) Turn on ("I") the power switch of the printer.

(2) (3) (4) (5) (6) (7) (8)

Do not disassemble the printer, if operating normally. Do not remove unnecessary parts: try to keep disassembly to a minimum. Use specified service tools. When disassembling, follow the determined sequence. Otherwise, parts may be damaged. Since screws, collars and other small parts are likely to be lost, they should temporarily be attached to the original positions. When handling ICs such as microprocessors, ROM and RAM, and circuit boards, follow standard electrostatic procedures. Do not place printed circuit boards directly on the equipment or floor.

No.

Service Tools

Tools

Qty

Place of Use

Remarks

1 2 3 4

No. 1-100 Philips screwdriver No. 2-200 Philips screwdriver, Magnetized No. 3-100 screwdriver No. 5-200 screwdriver

1 1 1 1

2-2.5 mm screws 3-5 mm screws

5 6 7 8

Digital multimeter Pliers Handy cleaner LED Head cleaner P/N 51802901

1 1 1 1 Cleans LED head

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 25

3.2 Parts Layout

Figure 3-1, Covers

Figure 3-2, Print Assemblies

Figure 3-3, Base Assemblies

Figure 3-4, Contact Assemblies

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 26

3.3 How to Change Parts

This section explains how to change parts and assemblies appearing in the disassembly diagram below. 3.3.1 Cover Assy Rear 3.3.2 Motor Fan (80-25) 3.3.3 Paper Eject Assy 3.3.4 Cover Assy Stacker Guide Eject FD Assy 3.3.5 Frame Assy Upper 3.3.6 Plate Support Assy 3.3.7 Limiter 2Way (L), (R) / Plate Guide (L), (R) 3.3.8 Cover 3.3.9 PCB Assy: PCE 3.3.10 Motor Fan (CU) 3.3.11 PXF PCB/PX4 PCB 3.3.12 Gear Heat Assy 3.3.13 Main Motor (A), (B) Assy 3.3.14 Gear One-way (Z30) 3.3.15 Motor Assy BT 3.3.16 Power Supply Unit, Holder Inlet, Sheet Insulation 3.3.17 Sensor Assy Box Toner 3.3.18 Square-shaped Connector 3.3.19 Hopping Motor 3.3.20 Gear One-Way 3.3.21 Feeder Unit Front 3.3.22 Manual Feed Hopper Assy 3.3.23 Guide Paper Input Assy 3.3.24 Lever Input Sensor 3.3.25 Roller Registration, Roller Assy Hopping 3.3.26 Roller Hopping 3.3.27 PXU PCB/PXM PCB, Lever Regist Sensor 3.3.28 Paper End Lever 3.3.29 PCO PCB (Operator Panel) 3.3.30 Holder Gear Toner Assy 3.3.31 Plate Latch Lever (FD), Spring Latch Lever (FD) 3.3.32 Belt Cassette Assy 3.3.33 High Voltage Power Supply Unit, Bracket HV 3.3.34 Erase Bracket Assy, Eraser Bracket 3.3.35 Shaft Link 3.3.36 Contact (BL-R) Assy, Contact (CL-R) Assy 3.3.37 Contact (BL-L) Assy, Contact (CL-L) Assy

3.3.38 Contact SB Assy 3.3.39 PXC PCB 3.3.40 Heat Unit Assy 3.3.41 Oil Roller Assy 3.3.42 Lever Lock Heat (L) / (R), Guide Side Heat, Spring Lock 3.3.43 PXL PCB 3.3.44 Heat Unit Guide Assy 3.3.45 Holder LED Assy, LED Head
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 27

3.3.1 Cover Assy Rear

Remove the 2 screws (1) then lift the cover assy rear (2) a little bit, then remove the cover assy rear by releasing the two claws.

Figure 3.3.1 Cover Assy Rear
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 28

3.3.2 Motor-Fan (80-25)

1. 2. 3. 4.

Remove the cover assy rear (See 3.3.1) Remove the two screws (1). Detach the fan motor (2) from the guide with its right side lifted then draw the fan motor. Detach the cable (3) then remove the fan motor (3).

Figure 3.3.2 Fan Motor (80-25)

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 29

3.3.3 Paper Eject Assy

The paper eject assy includes the frame: eject assy and the guide: paper eject assy. 1. 2. 3. 4. Remove the cover assy rear (See 3.3.1) Open the top cover. Unscrew 4 screws (1) then remove the frame eject assy (2). Remove the guide paper eject assy (3) by releasing the lock of one claw.

Figure 3.3.3 Paper Eject Assy

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 30

3.3.4 Cover Assy Stacker, Guide Eject FD Assy

1. 2. 3. 4.

Remove the cover assy rear. (See 3.3.1) Release the cable from the cable clamp (1) by opening the clamp. Unscrew 8 screws (2) then remove the cover assy stacker (3). Unscrew 4 screws (4) then remove the guide eject FD assy (5).

Figure 3.3.4 Cover Assy Stacker, Guide Eject FD Assy

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 31

3.3.5 Upper Frame Assy

1. 2. 3. 4. 5. 6. 7. 8.

Remove the cover assy rear. (See 3.3.1.) Remove the cover assy stacker. (See 3.3.4.) Remove the holder LED assy. (See 3.3.45) Detach the cable from the cable clamp (1) by releasing its lock. Remove connections of 4 connector cables (2) and 4 cables (3). Unscrew 4 screws (4) then remove the PCB (5). Unscrew 2 screw (6) then remove Guide Holder (7) by releasing the clamp of the claw. Unscrew 4 screws (8) then remove the Upper Frame Assy (9).

Figure 3.3.5 Upper Frame Assy
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 32

3.3.6 Plate Support Assemblies

The plate support assemblies are provided right and left. The method of those replacements is the same. 1. 2. 3. 4. 5. 6. Remove the heat unit assy. (See 3.3.40) Remove the cover assy rear. (See 3.3.1) Remove the cover assy stacker. (See 3.3.4) Remove the frame assy upper. (See 3.3.5) Detach the cable from the flat cable clip (1) by releasing the lock. Remove the 2 screws (2) then remove the plate support assy (3). Be careful not to lose the spring 4 which is removed with the plate support assy (3).)

Figure 3.3.6 Plate Support Assy
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 33

3.3.7 Limiter 2way (L), (R) / Plate Guide (L), (R)

1. 2. 3.

Remove the plate support assy (L) and (R). (See 3.3.6) Unscrew 2 screws (1) then remove the limiter 2way (L) (2) and the plate guide (L) (3). Unscrew 2 screws (4) then remove limiter 2way (R) (5) and the plate guide (R) (6).

Figure 3.3.7 Limiter 2way (L), (R) / Plate guide (L) , (R)
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 34

3.3.8 Cover

Describes the method of removing the cover assy side (L)/(R), cover assy OP panel, cover front (L)/(R) and the cover rear (L). 1. Remove the cover assy rear. (See 3.3.1) 2. Remove the cover assy stacker. (See 3.3.4) 3. Remove the 2 screws (1) then remove the frame side (L) (2). 4. Remove the 2 screws (3) then release the lock of the claw with the cover assy side (R) (4) lifted a little bit, then remove the cover assy side (R). 5. Detach the operator panel cable (5) from the PCM PCB. 6. Open the FDR unit front in the arrow direction. 7. Remove the 2 screws (6) then remove the cover assy OP panel (7). 8. Remove the 2 screws (8), with the cover front (R) (9) pushed up, then release the lock of the claw, then remove the cover front (R). 9. Remove the 2 screws (10) then remove the cover front (L) (11). 10. Remove the 2 screws (12) then remove the cover rear (L) (13). 11. Pull off the film (15) glued on the cassette guide. 12. Release the engagement with the guide by lifting the cover assy side (L) (14), then remove the cover assy side (L).

Figure 3.3.8 Cover
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 35

3.3.9 PCE PCB Assy

1. 2. 3. 4. 5. 6.

Open the top cover. Remove the 2 screws (1) and release the lock of the claw by lifting the cover assy side (R) (2) a little bit, then remove the cover assy side (R). Remove the 2 screws (8) to remove the plate shield (CU) (9). Remove the 3 screws (3) to remove the plate sealed (4). Detach the operator panel cable (5) from the PCE PCB. PCE PCB requires ten (10) screws for removal. Remove the 7 screws (6) to remove the PCE PCB (7).

Figure 3.3.9 PCB Assy: PCM

Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 36

3.3.10 Motor Fan (CU)

1. 2. 3.

Open the top cover. Remove the cover assy side (R), frame side (L), cover assy OP panel and the cover front (R). (See 3.3.8) Unplug the cable (1) and unscrew 2 screws (2), 2 collars (4) and then remove the motor fan (CU) (3).

Figure 3.3.10 Motor Fan

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 37

3.3.11 PXF PCB / PX4 PCB

Since the PXF PCB and PX4 PCB are connected with each other via the connector, remove them at the same time. 1. Remove the PCB assy : PCM. (See 3.3.9) 2. Unscrew 5 screws (1) then remove the cover CU (2). 3. Unplug all the cables (5) connected to the PXF PCB (3) and PX4 PCB (4). 4. Unscrew 5 screws (6) then remove the PXF PCB (3) and PX4 PCB (4) at the same time.

Figure 3.3.11 PXF PCB / PX4 PCB
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 38

3.3.12 Gear Heat Assy

1. 2. 3. 4. 5. 6. 7. 8.

Remove the cover assy side (R), cover assy OP panel, cover front (R) and the cover rear (L). (See 3.3.8) Remove the cover CU then unplug all the cables connected to the PX4 PCB and unscrew 3 screws. (See 3.3.11) Unplug all the cables connected to the PXF PCB then remove the PX4 PCB. (See 3.3.11) (Be careful not to
damage the connector when unplugging cables connected to the PXF PCB.)

Remove the heat unit assy. (See 3.3.40) Remove the guide paper eject assy. (See 3.3.3) Remove the motor fan (80-25). (See 3.3.2) Remove the 5 screws (1) and detach the cable (2) then remove the guide heat assy (3). Remove the 2 screws (4) then remove the motor (ID) (5).

Figure 3.3.12 Gear Heat Assy
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 39

3.3.13 Main Motor (A), (B) Assy

1. 2. 3. 4.

Remove the PXF PCB and PX4 PCB. (See 3.3.11) Remove the 4 screws (8) and remove 4 plate-Earth (9) and 4 lever Up/Dn 2 (1). Detach the all the cables (2) connected and unscrew 4 screws (3), then remove the main motor (A) assy (4). Detach the all the cables (5) connected and unscrew 3 screws (6), then remove the main motor (B) assy (7).

Figure 3.3.13 Main Motor (A), (B) Assy
Copyright 1999, Okidata, Division of OKI America, Inc. All rights reserved.

Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 40

3.3.14 Gear One-way (Z30)

Four gear one-ways (Z30) are provided but the method of those replacements is the same. Do not disassemble the gear one-ways (Z30) because they are assemblies which require adjustment. 1. 2. 3. 4. Remove the PCB assy : PCM. (See 3.3.9) Remove the cover CU. (See 3.3.11) Remove the 4 Plate-Earth and 4 lever Up/Dn 2. (See 3.3.13) Release the lock with the shaft by spreading the claw, then remove the gear one-way (Z30) (1).

[Notice for mounting] Mount the gear one-way (Z30) by fitting it with the shaft link turned in the arrow direction.

Figure 3.3.14 Gear One-Way (Z30)
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 41

3.3.15 Motor Assy Belt

1. 2.

Remove the main motor (B) assy. See (3.3.13) Unplug 2 cables (1) connected and unscrew 2 screws (2), then remove the motor assy belt (3).

Figure 3.3.15 Motor Assy Belt
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 42

3.3.16 Power Supply Unit, Holder Inlet, Sheet Insulation

1. 2. 3. 4. 5.

Remove the motor-fan (80-25). (See 3.3.2) Remove the frame side (L), the cover assy side (R) and the cover rear (L). (See 3.3.8) Unplug the cable (1). Remove the holder inlet (3) by unscrewing 2 screws (2), then remove the power switch (4) and unplug the AC socket (5). Draw the power supply unit (7) by unscrewing 2 screws (6), then unplug the cable (8).

Figure 3.3.16 Power Supply Unit, Holder Inlet, Sheet Insulation
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 43

3.3.17 Sensor Assy Box Toner

1. Remove the power supper unit. (See 3.3.16) 2. Unscrew the screw (1) then remove the sensor assy box toner (2) together with the bracket (3). 3. Unscrew the screw (4) then remove the sensor assy box toner (2).

Figure 3.3.17 Sensor Assy Box Toner
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 44

3.3.18 Square-shaped Connector

1. 2. 3.

Remove the power supply unit. (See 3.3.16) (Do not remove the power switch and AC socket from the holder inlet.) Unplug the cable (1). Remove cable (2), screw (5) and bracket (6) and cable (7) in order and then take off SW from bracket (6) to pull off square-shaped connector (4).

Figure 3.3.18 Square-shaped Connector
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 45

3.3.19 Motor - Pulse (ID)

1. 2. 3.

Remove the cover assy side (R), cover assy OP panel and the cover front (R). (See 3.3.8) Unscrew 2 screws (1) and unplug the cable (2), then remove the bracket hopping motor (3). (Be careful not to lose the gears (5), (6) and (7) which slip off at this time.) Unscrew 2 screws (8) then remove the hopping motor (3).

Figure 3.3.19 Motor - Pulse (ID)
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 46

3.3.20 One-way Gears

1. Remove the bracket hopping motor. (See 3.3.19). 2. Remove the spacer (4) first and release the locks with the shaft by spreading the claws of the gear one-way (1), (2) and (3), then remove the gear one-ways.

Figure 3.3.20 Gear One-way
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 47

3.3.21 Feeder Unit Front

1. 2. 3. 4. 5. 6.

Remove the cover assy side (R), cover assy OP panel, cover front (R) and the cover front (L). (See 3.3.8.) Remove the cover CU. (See 3.3.11) Unscrw the screw (8) and remove the cable (9). Unplug the cable (1) and unscrew the screw (2), then remove the bracket FF shaft (3). Remove 2 E-rings (4) then remove the feeder unit front (5). Unscrew each 2 screws (6) then remove 2 bracket FF links (7).

Figure 3.3.21 Feeder Unit Front

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 48

3.3.22 Manual Feed Hopper Assy

1. Open the manual feed hopper assy. 2. Release the engagement between the holder and the link then remove the manual feed hopper assy. (Be careful
not to damage the holder.)

Figure 3.3.22 Manual Feed Hopper Assy
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 49

3.3.23 Guide Paper Input Assy

1. 2. 3.

Remove the cover assy OP panel, cover front (R) ad the cover front (L). (See 3.3.8.) Remove the feeder unit front. (See 3.3.21) Unscrew 4 screws (1) then draw out the guide paper input assy (2) from the left side by rotating its upper part.
(Be careful not to damage the lever sensor resist).

Figure 3.3.23 Guide Paper Input Assy
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 50

3.3.24 Two Lever Input Sensors, Lever 2nd Feed Sensor

1. 2. 3.

Remove the guide paper input assy. (See 3.3.23.) Release the engagement with the guide by pressing the lever 2 input sensors (2) in the arrow direction, then remove them. Release the engagement with the guide by pressing the lever 2nd feed sensor (2) in the arrow direction, then remove the sensor.

Figure 3.3.24 Two Lever Input Sensors, Lever 2nd Feed Sensor
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 51

3.3.25 Roller Registration, Roller Assy Hopping

1. 2. 3. 4.

Remove the guide paper input assy. (See 3.3.23.) Remove the bracket hopping motor. (See 3.3.19) Remove the gear one-way. (See 3.3.20) Remove the holder gear toner assy. (See 3.3.30)

[Removal of the roller registration]

5. Remove the gear (1) and 2 bushes (2) and 2 bearings (3), then 2 roller registrations (4).
[Removal of the roller assy hopping]

6. Remove the bush (5) and the bearing (6). 7. Remove E-rings (9) of the sub-roller hopping at both sides of hopping roller and then release the lock of the roller hopping (7) with the shaft (8) by spreading the claw, then remove the roller hopping from the left side by the sliding shaft (8) in the arrow direction. (Be careful not to lose the knock-pin for fastening the roller hopping (7), which slisp
off together.)

Figure 3.3.25 Roller Registration, Roller Assy Hopping
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 52

3.3.26 Hopping Roller Assy

1. 2.

Remove the roller assy hopping. (See 3.3.25) and remove the 2 sub-roller hopping guide (3). (Be careful not to lose the knock-pin which clips off together when removing the roller assy hopping. Detach the roller hopping (2) from the shaft (1).

Figure 3.3.26 Hopping Roller Assy
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 53

3.3.27 PXU PCB/PXM PCB, Lever Resist Sensor

Since the PXU PCB and PXM PCB are connected with each other via the cable, remove them at the same time. 1. Remove the guide paper input assy. (See 3.3.23.) 2. Unscrew 4 screws (1) and unplug the cable (2), then remove the PXU PCB (3) and PXM PCB (4) at the same time. 3. Remove the lever resist sensor (5) by releasing the engagement with the guide.

Figure 3.3.27 PXU PCB/PXM PCB, Lever Resist Sensor
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 54

3.3.28 Paper End Lever

1. 2.

Remove the guide paper input assy. (See 3.3.23.) Remove the paper end lever (1) by releasing the engagement with the guide.

Figure 3.3.28 Paper End Lever
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 55

3.3.29 PCO PCB (Operator Panel)

1. 2. 3.

Remove the cover assy side (R), and the cover assy OP panel. (See 3.3.8.) Unscrew 4 screws (1) and unplug the operator panel cable (2). Remove the PCO PCB (3) by releasing 6 claws. (Be careful not to drop the LCD (Liquid Crystal Display) (4) and (5) which are detached together).

Figure 3.3.29 PCO PCB (Operator Panel)
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Chapter 3 Disassembly

Page: 56

3.3.30 Holder Gear Toner Assy

1. 2.

Remove the cover assy side (R), cover assy OP panel, cover front (R) and the cover front (L). (See 3.3.8.) Unplug the cable (1) and unscrew the screw (2), then remove the holder gear toner assy (3).

Figure 3.3.30 Holder Gear Toner Assy
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 57

3.3.31 Plate Latch Lever (FD), Spring Latch Lever (FD)

1. 2. 3. 4. 5. 6.

Remove the cover assy side (R), cover assy OP panel, cover front (R) and the cover front (L). (See 3.3.8.) Open the cover CU. (See 3.3.11) Unplug the cable (1). Unscrew 4 screws (4) then remove the stay upper (front) (5). Unscrew 2 screws (2) then remove the bracket SW (side) (5). Remove the plate latch lever (FD) (6) and spring latch lever (FD) (7) with the side frames spread. (Be careful not
to spread the frames too much).

Figure 3.3.31 Plate Latch Lever (FD), Spring Latch Lever (FD)

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 58

3.3.32 Transfer Belt

1. 2. 3. 4.

Open the Top cover. Release the lock by drawing the cover knob then open the cover assy side (L). Turn the waste toner box (box toner assy) (1) to the left by pressing it down, then remove it. Draw out the belt cassette assy (2) by lifting it a little bit with its handle.

Figure 3.3.32 Transfer Belt

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 59

3.3.33 High Voltage Power Supply Unit, Bracket HV (BT) Assy

1. 2. 3. 4. 5.

Remove the belt cassette assy. (See 3.3.32) Unscrew 2 screws (1) with the stacker cover opened, then remove the plate HV (2). Unplug the cable (3) and 7 codes (4). Unscrew 2 screws (5) then remove the high voltage power supply unit (6). Remove the bracket HV (BT) Assy (7).

Figure 3.3.33 High Voltage Power Supply Unit, Bracket HV (BT) Assy

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 60

3.3.34 Eraser Bracket Assy, Eraser Bracket (KCM) Assy

1. 2. 3.

Remove the belt cassette assy. (See 3.3.32). Open the stacker cover. Remove four screws (5) and then remove the Plate Blind (6).

[Removing the eraser bracket assy]

4. Remove the screw (1) and the connector (2). 5. Release the screw (7) and then remove the eraser bracket assy (3).
[Removing the eraser bracket (KCM) assy]

6. Remove the screw (1) and the connector (2). 7. Release the lock of the claw then release the engagement with the bracket sensor T (KCM). (See 3.3.35). 8. Release the screw (7) and then remove the eraser bracket (KCM) assy (4) and unplug the cable (2) then remove the eraser bracket (KCM) assy.

Figure 3.3.34 Eraser Bracket Assy, Eraser Bracket (KCM) Assy

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 61

3.3.35 Shaft Link

1. 2. 3. 4.

Remove the eraser bracket assy. (See 3.3.34) Remove the gear one-way (Z30). (See 3.3.14.) Remove the E-ring (3) by sliding the sensor assy T (KCM) (1) and bracket sensor T (KCM) (2) together in the arrow (A) direction. Release the engagement between the lever Up/Dn and boss A of the lever link (R) (5) by sliding the spring support (R) (4), lever link (R) (5) and the bearing (6) together in the arrow (B) direction. (Keep on sliding until
the lever link (R) (5) reaches the end of D-cut part of the shaft link (7).)

5. 6. 7.

Draw out the entire shaft link (7) by pressing it in the arrow (C) direction and turning its left side under the contact (BL L) assy. Detach the sensor assy T (KCM) (1), bracket sensor T (KCM) (2), spring support (R) (4), lever link (R) (5) and the bearing (6) from the shaft link (7). Remove 2 E-rings (8) then remove the spring support (L) (9) and lever link (L) (10).

[Notice for mounting]
l

Engagement between the lever Up/Dn and boss A of the lever link (R) (5): Mount the spring support (L (9) and lever link (L (10) in the predetermined positions, then clamp the boss A of lever link (R) (5) with the lever Up/Dn by adding rotating power on the spring support (L) (9) by rotating the shaft link (7). Mounting of the spring support (R) (4): Clamp the spring support (R) (4) at the predetermined positions in the lever link (R) (5) and the contact BKT (R).

l

Figure 3.3.35 Shaft Link
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 62

3.3.36 Contact Bracket (BL-R) Assy, Contact Bracket (CL-R) Assy

1. 2. 3. 4.

Remove the gear one-way (Z30). (See 3.3.14) Remove the motor assy BT. (See 3.3.15) Remove the high voltage power supply unit. (See 3.3.33) Remove the shaft link. (See 3.3.35)

[Removal of the contact (BL-R) Assy]

5. Unscrew 2 screws (1) and unplug the cable (2), then rmeove the contact (BL-R) assy (3).
[Removal of the contact (CL-R) Assy]

6. Unscrew 2 screws (4) then remove the contact (CL-R) Assy (5).

Figure 3.3.36 Contact Bracket (BL-R) Assy, Contact Bracket (CL-R) Assy
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Chapter 3 Disassembly

Page: 63

3.3.37 Contact (BL-L) Assy, Contact (CL-L) Assy

1.

Remove the shaft link. (See 3.3.35)

[Removal of the contact (BL-L) assy]

2. Unscrew 2 screws (1) then remove the contact (BL-L) Assy (2).
[Removal of the contact (CL-L) assy]

3. Unscrew 2 screws (3) then remove the contact (CL-L) assy (4).

Figure 3.3.37 Contact (BL-L) Assy, Contact (CL-L) Assy

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 64

3.3.38 Contact SB Assy

1. 2. 3. 4.

Remove the contact (BL-L) assy and contact (CL-L) assy. (See 3.3.37) Unscrew 3 screws (1) then remove the plate blind (2). Unplug 7 codes (3). Unscrew 3 screws (4) then remove the contact SB assy (5).

Figure 3.3.38 Contact SB Assy
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 65

3.3.39 PXC PCB

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Remove the contact (BL-R) assy and contact (CL-R) assy. (See 3.3.36) Remove the contact (BL-L) assy and contact (CL-L) assy. (See 3.3.37) Remove the hopping motor. (See 3.3.19) Remove the motor assy BT. (See 3.3.15) Remove the gear heat assy. (See 3.3.12) Remove the roller assy hopping. (See 3.3.25) Remove the holder gear toner assy. (See 3.3.30) Remove the high voltage power supply unit. (See 3.3.33) Unplug the inlet AC. (See 3.3.16) Unscrew 9 screws (1) then remove the guide cassettes (L) (2) and (R) (3) together. Unscrew the screw (4) then remove the switch (5). Unscrew the screw (6) then remove the PXC PCB (7).

Figure 3.3.39 PXC PCB
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 66

3.3.40 Heat Unit Assy (Fuser unit and oil roller)

1. 2.

Open the stacker cover. Release the lock by turning down the lever lock heat guides (blue) on both sides, then lift the fuser unit assy (1) and remove it.

Figure 3.3.40 Heat Unit Assy

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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 67

3.3.41 Oil Roller Kit

1. 2.

Remove the heat unit assy. (See 3.3.40) Release the lock by turning down the lever in the arrow (A) direction, then slide the oil roller assy (1) with its right side lifted and remove it.

Figure 3.3.41 Oil Roller Kit
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Service Guide - OKICOLOR8
Chapter 3 Disassembly

Page: 68

3.3.42 Lever Lock Heat (L)/(R), Guide Side Heat, Spring Lock

Removing methods for right side and left sid