Ricoh FW 7030D Service Manual

®

®

®

RICOH GROUP COMPANIES

A741

SERVICE MANUAL

PN: RCSM7030

®

®

®

SERVICE MANUAL

A741

RICOH GROUP COMPANIES

A741

SERVICE MANUAL

PN:RCSM7030

LEGEND

PRODUCT

CODE

GESTETNER RICOH SAVIN

A741 --- FW7030D ---

COMPANY

DOCUMENTATION HISTORY

REV. NO. DATE COMMENTS

* 7/98 Original Printing

CAUTION

DANGER OF EXPLOSION IF BATTERY IS INCORRECTLY RE­PLACED. REPLACE ONLY WITH THE SAME OR EQUIVALENT
TYPE RECOMMENDED BY THE MANUFACTURER. DISPOSE
OF USED BATTERIES ACCORDING TO THE MANUFAC­TURER’S INSTRUCTIONS.

ATTENTION

IL Y A DANGER D’EXPLOSION S’IL Y A REMPLACEMENT IN­CORRECT DE LA BATTERIE. REMPLACER UNIQUEMENT
AVEC UNE BATTERIE DU MÊME TYPE OU D’UN TYPE REC­OMMANDÉ PAR LE CONSTRUCTEUR. METTRE AU RÉBUT
LES BATTERIES USAGÉES CONFORMÉMENT AUX INSTRUC­TIONS DU FABRICANT.

Safety precautions

This booklet provides safety warnings and precautions for our service
personnel to ensure the safety of their customers, their machines as well
as themselves during maintenance activities. Service personnel are
advised to read this booklet carefully to familiarize themselves with the
warnings and precautions described here before engaging in
maintenance activities.

Safety warnings and precautions

Various symbols are used to protect our service personnel and
customers from physical danger and to prevent damage to their
property. These symbols are described below:

DANGER: High risk of serious bodily injury or death may result from

insufficient attention to or incorrect compliance with warning
messages using this symbol.

WARNING: Serious bodily injury or death may result from insufficient

attention to or incorrect compliance with warning messages
using this symbol.

CAUTION: Bodily injury or damage to property may result from

insufficient attention to or incorrect compliance with warning
messages using this symbol.

Symbols

The triangle (
and caution. The specific point of attention is shown inside
the symbol.

) symbol indicates a warning including danger

General warning.

Warning of risk of electric shock.

Warning of high temperature.

indicates a prohibited action. The specific prohibition is

shown inside the symbol.

General prohibited action.

Disassembly prohibited.

indicates that action is required. The specific action

required is shown inside the symbol.

General action required.

Remove the power plug from the wall outlet.

Always ground the copier.

1. Installation Precautions

WARNING

• Do not use a power supply with a voltage other than that specified.
Avoid multiple connections to one outlet: they may cause fire or electric
shock. When using an extension cable, always check that it is

adequate for the rated current. ...............................................................

• Connect the ground wire to a suitable grounding point. Not grounding
the copier may cause fire or electric shock. Connecting the earth wire
to an object not approved for the purpose may cause explosion or
electric shock. Never connect the ground cable to any of the following:
gas pipes, lightning rods, ground cables for telephone lines and water

pipes or faucets not approved by the proper authorities.........................

CAUTION:

• Do not place the copier on an infirm or angled surface: the copier may

tip over, causing injury. ...........................................................................

• Do not install the copier in a humid or dusty place. This may cause fire

or electric shock......................................................................................

• Do not install the copier near a radiator, heater, other heat source or

near flammable material. This may cause fire. .......................................

• Allow sufficient space around the copier to allow the ventilation grills to
keep the machine as cool as possible. Insufficient ventilation may

cause heat buildup and poor copying performance................................

• Always handle the machine by the correct locations when moving it.....

• Always use anti-toppling and locking devices on copiers so equipped.
Failure to do this may cause the copier to move unexpectedly or

topple, leading to injury. ..........................................................................

• Avoid inhaling toner or developer excessively. Protect the eyes. If toner
or developer is accidentally ingested, drink a lot of water to dilute it in
the stomach and obtain medical attention immediately. If it gets into the
eyes, rinse immediately with copious amounts of water and obtain

medical attention.....................................................................................

• Advice customers that they must always follow the safety warnings and

precautions in the copier’s instruction handbook. ...................................

2. Precautions for Maintenance

WARNING

• Always remove the power plug from the wall outlet before starting

machine disassembly. ............................................................................

• Always follow the procedures for maintenance described in the service

manual and other related brochures. ......................................................

• Under no circumstances attempt to bypass or disable safety features

including safety mechanisms and protective circuits. .............................

• Always use parts having the correct specifications. ...............................

• Always use the thermostat or thermal fuse specified in the service
manual or other related brochure when replacing them. Using a piece

of wire, for example, could lead to fire or other serious accident............

• When the service manual or other serious brochure specifies a
distance or gap for installation of a part, always use the correct scale

and measure carefully. ...........................................................................

• Always check that the copier is correctly connected to an outlet with a

ground connection. .................................................................................

• Check that the power cable covering is free of damage. Check that the
power plug is dust-free. If it is dirty, clean it to remove the risk of fire or

electric shock. .........................................................................................

• Never attempt to disassemble the optical unit in machines using lasers.

Leaking laser light may damage eyesight...............................................

• Handle the charger sections with care. They are charged to high

potentials and may cause electric shock if handled improperly..............

CAUTION

• Wear safe clothing. If wearing loose clothing or accessories such as
ties, make sure they are safely secured so they will not be caught in

rotating sections......................................................................................

• Use utmost caution when working on a powered machine. Keep away

from chains and belts..............................................................................

• Handle the fixing section with care to avoid burns as it can be

extremely hot..........................................................................................

• Check that the fixing unit thermistor, heat and press rollers are clean.

Dirt on them can cause abnormally high temperatures. .........................

• Do not remove the ozone filter, if any, from the copier except for

routine replacement. ...............................................................................

• Do not pull on the AC power cord or connector wires on high-voltage

components when removing them; always hold the plug itself...............

• Do not route the power cable where it may be stood on or trapped. If

necessary, protect it with a cable cover or other appropriate item. ........

• Treat the ends of the wire carefully when installing a new charger wire

to avoid electric leaks. ............................................................................

• Remove toner completely from electronic components. .........................

• Run wire harnesses carefully so that wires will not be trapped or

damaged.................................................................................................

• After maintenance, always check that all the parts, screws, connectors
and wires that were removed, have been refitted correctly. Special
attention should be paid to any forgotten connector, trapped wire and

missing screws. ......................................................................................

• Check that all the caution labels that should be present on the machine
according to the instruction handbook are clean and not peeling.

Replace with new ones if necessary.......................................................

• Handle greases and solvents with care by following the instructions

below: .....................................................................................................

· Use only a small amount of solvent at a time, being careful not to

spill. Wipe spills off completely.

· Ventilate the room well while using grease or solvents.

· Allow applied solvents to evaporate completely before refitting the

covers or turning the main switch on.

· Always wash hands afterwards.

• Never dispose of toner or toner bottles in fire. Toner may cause

sparks when exposed directly to fire in a furnace, etc..........................

• Should smoke be seen coming from the copier, remove the power

plug from the wall outlet immediately. ..................................................

3. Miscellaneous

WARNING

• Never attempt to heat the drum or expose it to any organic solvents
such as alcohol, other than the specified refiner; it may generate toxic

gas. .........................................................................................................

CONTENTS

I THEORY AND CONSTRUCTION SECTION

1-1 Specifications

1-1-1 Specifications ................................................................................ 1-1-1

1-2 Handling Precautions

1-2-1 Handling and storage of the drum ................................................. 1-2-1

1-2-2 Storage of developer and toner..................................................... 1-2-1

1-2-3 Handling of the heaters ................................................................. 1-2-1

1-2-4 Storage of paper ........................................................................... 1-2-1

1-3 Mechanical Construction

1-3-1 Part names and functions ............................................................. 1-3-1

1-3-2 Copy process ................................................................................ 1-3-3

1-3-3 Machine cross sectional view........................................................ 1-3-3

1-3-4 Machine drive system ................................................................... 1-3-4

1-3-5 Mechanical construction of each section ...................................... 1-3-8

II ELECTRICAL SECTION

2-1 Electrical Parts Layout

2-1-1 Electrical parts layout .................................................................... 2-1-1

2-2 Detection of Paper Misfeed

2-2-1 Paper misfeed detection ............................................................... 2-2-1

2-2-2 Paper misfeed detection conditions .............................................. 2-2-2

2-3 Operation of the PCBs

2-3-1 Power source PCB ........................................................................ 2-3-1

2-3-2 LPH power supply PCB................................................................. 2-3-7

2-3-3 Servo motor control 1 PCB ......................................................... 2-3-10

2-3-4 Servo motor control 2 PCB ......................................................... 2-3-13

2-3-5 Main PCB .................................................................................... 2-3-16

2-3-6 Backup PCB ................................................................................ 2-3-25

2-3-7 ISU PCB ...................................................................................... 2-3-26

2-3-8 Operation unit PCB ..................................................................... 2-3-29

2-3-9 Inverter PCB................................................................................ 2-3-30

340

III SET UP AND ADJUSTMENT SECTION

3-1 Installation

3-1-1 Unpacking and installing the copier .............................................. 3-1-1

3-1-2 Copy mode initial settings ........................................................... 3-1-27

3-1-3 Installing the key counter (optional) ............................................ 3-1-28

3-1-4 Attaching a roll unit heater (optional) .......................................... 3-1-31

3-2 Simulation

3-2-1 Simulation function ........................................................................ 3-2-1

3-3 Assembly and Disassembly

3-3-1 Cautions during disassembly and assembly ................................. 3-3-1

3-3-2 Paper feed section ........................................................................ 3-3-3

3-3-3 Main charger section ................................................................... 3-3-10

3-3-4 Exposure and original feed section ............................................. 3-3-19

3-3-5 Developing section ...................................................................... 3-3-31

1-1-1

340

3-3-6Transfer/separation section......................................................... 3-3-37

3-3-7Cleaning section.......................................................................... 3-3-42

3-3-8Fixing section.............................................................................. 3-3-48

3-3-9Other sections............................................................................. 3-3-60

3-4PCB Initial Settings

3-4-1Main PCB...................................................................................... 3-4-1

3-4-2Non-field-adjustable volume controls............................................ 3-4-3

3-5Self Diagnostics

3-5-1Self-diagnostic function................................................................. 3-5-1

3-6Troubleshooting

3-6-1Image formation problems............................................................ 3-6-1

3-6-2Paper misfeeds........................................................................... 3-6-17

3-6-3PCB terminal voltages................................................................. 3-6-23

3-6-4Electrical problems...................................................................... 3-6-38

3-6-5Mechanical problems.................................................................. 3-6-51

3-7Appendixes

Timing chart No. 1...................................................................................... 3-7-1

Timing chart No. 2...................................................................................... 3-7-2

Timing chart No. 3...................................................................................... 3-7-3

Timing chart No. 4...................................................................................... 3-7-4

Timing chart No. 5...................................................................................... 3-7-5

Operation unit PCB..................................................................................... 3-7-6

Power source PCB 1/2................................................................................ 3-7-7

Power source PCB 2/2................................................................................ 3-7-8

Detachable unit wiring diagram................................................................... 3-7-9

1-1-2

I

THEORY AND

CONSTRUCTION

SECTION

CONTENTS

1-1 Specifications

1-1-1 Specifications ...................................................................................... 1-1-1

340

1-1-5

1-1-1 Specifications

Type ……………………………Console type
Copying method ……………… Dry indirect electrostatic photocopying
Original type …………………… Sheet
Original feed method ………… Moving originals
Paper …………………………… (1) Plain paper: 64 – 80 g/m2 (fed from the roll unit or

bypass table)

(2) Special paper: Tracing paper, film (fed from the roll

unit or bypass table)

Roll paper size ………………… Width: 420 – 920 mm/17" – 36"

Diameter: 180 mm/61/4" maximum
Inner diameter: 76 mm/3"
Length: 175 m

Original sizes …………………Standard: A0 – A4R (64 – 80 g/m2)

36" × 48" – 81/2" × 11" (64 – 80 g/m2)

Maximum: 920 (w) × 5,000 (l) mm (64 – 80 g/m2)

36" × 197" (64 – 80 g/m2)

Copy sizes …………………… Standard: A0 – A4R (64 – 80 g/m2)

36" × 48" – 81/2" × 11" (64 – 80 g/m2)

Maximum: 920 (w) × 5,000 (l) mm (64 – 80 g/m2)

36" × 197" (64 – 80 g/m2)
Effective image width: 920 mm
Leading edge margin: 5 ± 4 mm

Copying magnification
ratios …………………………… Manual mode: 25 – 400%

(at intervals of 1% or 0.1%)
Auto copy mode:

Fixed ratios according to the original and paper
sizes

Metric:

1:1±0.5%, 1:4.000, 1:2.829, 1:2.000, 1:1.410,
1:0.706, 1:0.500, 1:0.352, 1:0.250

Inch (Architecture):

1:1±0.5%, 1:3.143, 1:2.588, 1:2.000, 1:1.294,
1:0.640, 1:0.500, 1:0.324, 1:0.250

Inch (Engineer):

1:1±0.5%, 1:4.000, 1:2.667, 1:2.000, 1:1.333,

1:0.667, 1:0.500, 1:0.333, 1:0.250
Copying speed ………………… 4.8 m/min
First copy time …………………30 s maximum (A1 standard size copying)
Warmup time …………………10 min maximum (room temperature 20°C/68°F,

65% RH)

Paper feed system …………… Automatic feed from the roll unit and manual feed from

the bypass table

Consecutive copying …………1 – 20 copies (when the original length is 1300 mm

or less)

340

1-1-1

340-1

Photoconductor ………………OPC (Drum diameter: 90 mm)
Charging system ………………Single plus corona charging

Drum surface potential: 870 ± 50 V DC
Exposure system ……………… Moving original scanning
Light source …………………… Fluorescent lamp, 65 W
Developing system …………… Dry (magnetic brush)

Developer: Dual-component (ferrite carrier and black

toner: N22T)

Toner density control: Toner sensor

Toner replenishing: Automatic supply from the toner

hopper
Transfer system ……………… Single negative corona charging: –5.3 kV DC
Separation system …………… Single AC corona charging: 5.6 kV AC
Fixing system …………………Heat roller

Heat source: Halogen heaters

120 V areas: 800 W (main), 400 W (sub)

220 – 240 V areas: 1120 W (main), 480 W (sub)

Control temperature: 150°C/302°F (plain paper or film)

145°C/293°F (tracing paper)

Abnormal temperature increase-prevention device:

Thermostat, 145°C/293°F

Fixing pressure: 2.0 N at both ends, 5.9 N at center
Charge erasing system ……… Exposure by cleaning lamp
Cleaning system ………………Cleaning blade and cleaning fur brush
Functions ……………………… (1) Preheat/energy saving

(2) Auto clear (can be set to between 30 and 270 s at

intervals of 30 s)

(3) Auto shutoff (can be set to between 15 and

120 min at intervals of 15 min)
(4) Self-diagnostics
(5) Simulation
(6) Margin copy
(7) Hanging copy
(8) Program copy
(9) Preview copy

(10) Paper cut length setting
(11) Same-size/full-size magnification adjustment
(12) Fixing temperature adjustment
(13) Initial settings change
(14) Original size detection
(15) Paper size detection

Power requirement …………… 120 V AC, 60 Hz, 13 A

220 – 240 V AC, 50/60 Hz, 8 A

Power consumption ……………

Machine dimensions …………1355 (w) × 635 (d) × 1107 (h) mm

Weight …………………………Approx. 268 kg, 590.3 lb. (main unit only)
Floor requirement …………… 1355 (w) × 707 (d) mm, 533/8" (w) × 2713/16" (d)

1500

W (120 V areas)

1900

W (220 – 240 V areas)

533/8" (w) × 25" (d) × 439/16" (h)

1-1-2

Accessories ……………………Original reversing guide
Optional accessories ………… 3rd roll unit, roll shaft, carrier sheets (A0, A1, A2), key

counter and original support

3rd roll unit (optional)

Type ……………………………Built-in type
Paper …………………………… Equivalent to the copier to be connected to
Power source …………………Electrically connected to the copier

340

1-1-3

CONTENTS

1-2 Handling Precautions

1-2-1 Handling and storage of the drum ....................................................... 1-2-1

1-2-2 Storage of developer and toner .......................................................... 1-2-1

1-2-3 Handling of the heaters ....................................................................... 1-2-1

1-2-4 Storage of paper ................................................................................. 1-2-1

340

1-1-7

340

1-2-1 Handling and storage of the drum

Use the following caution when handling the drum.

• When removing the drum from the main unit, make sure not to expose it to direct sunshine
or strong lighting.

• Store the drum where the ambient temperature is kept between –20°C/–4°F and 40°C/
104°F and humidity around 85%RH. Sudden changes in temperature and humidity even
within the permitted ranges should be avoided, too.

• Avoid atmosphere laden with substances that might chemically damage the drum surface.

• Never hit the drum surface with anything hard or pointed. Protect it from bare or gloved
hands; if it is accidentally touched, clean by following the proper procedure.

1-2-2 Storage of developer and toner

Store developer and toner in a cool, dark place free from direct sunshine or high humidity.

1-2-3 Handling of the heaters

This copier is equipped with heaters to avoid condensation inside. These heaters are kept
powered as long as the copier power cable is connected to a wall outlet with the main switch
set off. Never disconnect the power cable if the copier is used in a humid place of 70%RH
higher.
If the copier is not going to be used for long periods of time, disconnect the power cable from
the wall outlet.
Each roll unit of this copier is equipped with a roll unit heater*1 which can be individually
turned on or off with a switch. If normal plain paper is kept in the roll units and there is a risk
of high humidity, keep their heaters on. However, keep the heater off if tracing paper is kept
in the roll unit.

1-2-4 Storage of paper

Paper should be stored in a cool, dark place free from high temperature or humidity. If it is
not going to be used for a long time, take paper out of the roll unit, put it in the original
wrapping paper and seal.

*1 Optional for 220 – 240 V models.

1-2-1

CONTENTS

1-3 Mechanical Construction

1-3-1 Part names and functions ................................................................... 1-3-1

1-3-2 Copy process ...................................................................................... 1-3-3

1-3-3 Machine cross sectional view ............................................................. 1-3-3

1-3-4 Machine drive system ......................................................................... 1-3-4

(1) Drive system 1 (driven by the paper feed motor) ........................ 1-3-4

(2) Drive system 2 (driven by the paper feed motor) ........................ 1-3-5

(3) Drive system 3 (driven by the drum motor and fixing

drive motor) ................................................................................. 1-3-6

(4) Drive system 4 (driven by the drive motor and toner

feed motor) .................................................................................. 1-3-6

(5) Drive system 5 (driven by the original feed motor) ...................... 1-3-7

1-3-5 Mechanical construction of each section ............................................ 1-3-8

(1) Paper feed section ...................................................................... 1-3-8

Winding operation of paper roll ................................................. 1-3-10

(1-1) Bypass paper feed .......................................................... 1-3-12

(1-2) Roll unit paper feed ........................................................ 1-3-13

(2) Main charger section ................................................................. 1-3-15

Drum surface potential correction ............................................. 1-3-18

(3) Exposure and original feed section ........................................... 1-3-19

(4) CIS and LPH section ................................................................. 1-3-22

Original image reading .............................................................. 1-3-24

Static latent image formation..................................................... 1-3-24

CIS correction............................................................................ 1-3-26

(5) Developing section .................................................................... 1-3-28

Forming the magnetic brush...................................................... 1-3-29

Temperature compensation of the toner sensor output ............ 1-3-30

Toner sensor output correction based on the copy count ......... 1-3-31

Toner density control................................................................. 1-3-32

(6) Transfer/separation section ....................................................... 1-3-33

(7) Cleaning section ........................................................................ 1-3-36

(8) Static eliminator section ............................................................ 1-3-39

(9) Fixing section ............................................................................ 1-3-41

Heating and temperature control of heat roller and

press roller................................................................................. 1-3-43

340

1-1-9

1-3-1 Part names and functions

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1 Main switch
2 Total counter
3 Front covers
4 Carrier sheet guides
5 Copy bins
6 Bypass slot
7 Bypass table
8 Main body release levers
9 Original guide
0 Paper eject guides

*1 Optional.
*2 Optional for 220 – 240 V models.

! Original table
@ Original loop guide
# Original insert slot
$ Copy eject slot
% Operation panel
^ Right cover
& Key counter
* Copy ready indicator

(ready lamp)

( Fuser release button

*1

) Original holding section
⁄ Original holder anchor pins
¤ Upper rear cover screws
‹ Upper rear cover
› Transport knob
fi Waste toner tank
fl Copy bin stopper plates
‡ Second roll unit
— First roll unit

· Instruction handbook box

‚ Roll unit handle
ΠPaper roll insertion cover
„ Paper roll insertion latches
´ Roll unit heater switch
‰ Paper roll shaft
ˇ Paper roll size label
Á Paper roll release lever
¨ Paper roll shaft gear
ˆ Copy eject slot guides

*2

1-3-1

340-3

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1-3-2

1 Preheat/energy saver key/indicator
2 Preview copy key
3 All clear/reset key
4 Job stop/roll cut key
5 Stop/clear key
6 Numeric keys
7 Mode set keys
8 Enter key

9

Leading edge margin key/indicators

0 Left margin key/indicators
! Leading edge hanging key/indicators

Figure 1-3-2 Operation panel

@ Trailing edge hanging key/indicators
# Copy mode select key/indicators
$ Zoom mode select key/indicators
% Paper length key/indicators
^ Paper source key/indicators
& Auto/manual contrast select key/indicators
* Copy contrast keys
( Copy contrast indicators
) Original contrast key/indicators
⁄ Special paper select key/indicators
¤ Image process select key/indicators

‹ Added features key
› Memory recall key
fi Fusing temp. adjusted indicator
fl Display
‡ Add paper indicator
— Add toner indicator

· Maintenance indicator
‚ Interrupt key/indicator
ΠMemory copy key/indicator

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On-line key/indicator

340

1-3-2 Copy process

1 Exposure

Fluorescent lamp
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3 Static latent 

5 Developing

Paper

image formation
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LPH

Drum

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2 Original image reading

CIS

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4 Main charging
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8 Fixing

1-3-3 Machine cross sectional view

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6 Transfer 7 Separation

Figure 1-3-3 Copy process

*1: The third roll unit is optional.

Figure 1-3-4 Machine cross sectional view

1 Paper feed section (page 1-3-8)
2 Main charger section (page 1-3-15)
3 Exposure and original feed section (page 1-3-19)
4 CIS and LPH section (page 1-3-22)
5 Developing section (page 1-3-28)
6 Transfer/separation section (page 1-3-33)
7 Cleaning section (page 1-3-36)
8 Static eliminator section (page 1-3-39)
9 Fixing section (page 1-3-41)

1-3-3

340-1

1-3-4 Machine drive system

(1) Drive system 1 (driven by the paper feed motor)

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1 Paper feed motor pulley 15/18
2 Cutter drive belt
3 Drive tension pulley
4 Cutter drive pulley 20
5 SB gear 37
6 Cutter clutch gear
7 Cutter drive gear 21
8 Duplex gear 32
9 Paper feed section drive belt 1
0 Drive tension pulley
! Paper feed pulley 16
@ Pre-transfer drive gear
# Optical section idle gear 46
$ Roll paper conveying clutch gear
% Idle gear 45
^ Paddle gear
& Optical section idle gear 46
* SB gear 37

*1: Parts 29 to 36 are present when the third roll unit (optional) is installed.

( Bypass registration clutch gear
) Gear 50T
⁄ Registration clutch gear
¤ Paper feed pulley 16
‹ Idle gear 36/30
› Middle feed clutch gear
fi Optical section idle gear 46
fl Idle gear 20/26
‡ Middle roll winding clutch gear
— Pulley 20P5

· Paper feed section drive belt 2
‚ Pulley 20P5
ΠPaper feed pulley 16
„ Idle gear 36/30
´ Lower feed clutch gear
‰ Optical section idle gear 46
ˇ Idle gear 20/26
Á Lower roll winding clutch gear

*1

*1

*1

*1

*1

*1

*1

*1

1-3-4

Figure 1-3-5 Drive system 1 (outer side to the left frame)

(2) Drive system 2 (driven by the paper feed motor)

340-1

5

4
3

2

7

6

9

8

1

(

)

0

!

@

⁄

¤

#

›

%

‹

fi

$

^

&

*

1 Cutter drive gear 21
2 Cutter gear 32
3 Eject gear 29
4 Fixing unit idle gear 24T
5 Duplex gear 32
6 Drive gear 20T
7 Drive gear 20T
8 Paper feed pulley gear B
9 Paper feed pulley gear B
0 Idle gear 22
! Paper feed pulley gear B
@ Upper roll winding clutch gear
# Drive gear 20T

*1: Parts 24 and 25 are present when the third roll unit (optional) is installed.

$ Idle gear 16/25
% Duplex gear 32
^ Roll idle gear A
& Spiral roller gear 23
* Roll gear 40
( Duplex gear 32
) Upper feed clutch gear
⁄ Drive gear 20T
¤ Roll drive gear 16
‹ Roll gear 40
› Roll drive gear 16
fi Roll gear 40

*1

*1

Figure 1-3-6 Drive system 2 (inner side from the left frame)

1-3-5

340

(3) Drive system 3 (driven by the drum motor and fixing drive motor) (4) Drive system 4 (driven by the drive motor and toner feed motor)

(
*

&

9

1

2

0

3

4

!

5

8

6

7



^



%

¤

*



#

‹

$

(

&

@

)

⁄

%

$

#

@

^

!

0

9

1

3

2

5

4

6

7

8

1-3-6

Figure 1-3-7 Drive system 3 (outer side to the left frame)

1 Main drive pulley
2 Drive tension pulley
3 Pre-transfer drive belt
4 Pre-transfer drive pulley 32
5 Developer gear
6 Drum motor gear 17
7 Drum drive gear 45
8 Drum drive gear 60
9 Developing unit drive belt
0 Tension pulley
! Developing unit drive pulley 16
@ Fixing drive motor gear

# Fixing section drive gear
$ Developer gear 22
% Idle gear 34
^ Idle gear 26
& SB gear 24
* Heat roller gear
( Fixing gear 24
) Idle gear 22
⁄ Sleeve gear 17
¤ Fixing unit idle gear
‹ Gear 27T

Figure 1-3-8 Drive system 4 (inner side from the left frame)

1 Pre-transfer drive gear 22
2 Drive gear 20T
3 Pre-transfer gear 30
4 Drum joint
5 Left drum flange
6 Feed gear 25
7 Fur brush gear 17
8 Roll unit gear 18
9 Developing unit drive gear 20
0 Developing roller gear 19
! Developing unit idle gear 17

@ Developer paddle gear
# Spiral roller gear 23
$ Toner shaft gear
% Toner shaft gear
^ Fixing idle gear

(left side of the machine)

& Toner feed motor gear

(right side of the machine)

* Toner gear 34
( Toner gear 34

(5) Drive system 5 (driven by the original feed motor)

340

0

!

6

9

8

7

5

4

Figure 1-3-9 Drive system 5 (outer side to the right frame)

1 Original feed motor pulley
2 Original feed drive belt 1
3 Idle pulley 16
4 Tension pulley
5 Original feed clutch gear
6 Developing unit pulley

7 Front lower original roller
8 Front upper original roller
9 Original feed pulley
0 Original feed drive belt 2
! Original feed pulley

3

2

1

1-3-7

340

1-3-5 Mechanical construction of each section

(1) Paper feed section

The paper feed section is comprised of the parts shown in Figure 1-3-10. Paper can be fed
either manually or automatically from a paper roll.
In the paper feed section, a sheet of paper fed from the roll unit or placed on the bypass table
is conveyed to the transfer section in synch with the LED on timing of the LPH section.

2

7

1

9

8

0

*

´

∏

(

¤
‚

Œ

Å

)

Á

„

·

Ø

6

!

3

°

ˆ

‡

^

&

¨

5

%

⁄

$

fl

ˇ

‹

4

@

#

›

fi

‰

1-3-8

Figure 1-3-10 Paper feed section

340

1 Registration upper guide
2 Bypass pulley
3 Registration lower guide
4 Bypass table
5 Bypass registration roller
6 Registration roller
7 Cutter eject rear guide
8 Registration pulley
9 Cutter unit
0 Cutter rear guide
! Cutter front guide
@ Roll lever
# Roll base A
$ Paper roll shaft
% Roll paper feed upper guide A
^ Roll paper feed upper roller
& Roll paper feed lower roller A
* Roll paper conveying rear roller A
( Roll paper conveying front roller
) Roll stay A

¤ Roll paper conveying upper guide
‹ Center partition
› Roll lever
fi Roll base B
fl Paper roll shaft
‡ Roll paper feed upper guide B
— Roll paper feed upper roller

· Roll front guide B
‚ Roll rear guide B
ΠRoll paper conveying rear roller B
„ Roll paper conveying lower guide
´ Roll paper conveying rear guide
‰ Roll lever
ˇ Paper roll shaft
Á Roll base B

*1

*1

*1

¨ Roll paper feed upper guide B
ˆ Roll paper feed upper roller
Ø Roll front guide B
” Roll rear guide B

*1

*1

Å Roll paper conveying rear roller C

⁄ Roll paper feed lower guide A

*1 Parts 34 to 41 are present when the third roll unit (optional) is installed.

MPCB

CN3-14



CN3-34
CN6-14



CN6-7
CN3-11

CN6-8
CN7-12
CN7-13
CN6-9
CN3-9

CN4-8A
CN3-10
CN4-9A
CN7-14

CN3-26
CN3-28
CN3-29

CN6-10
CN7-16
CN6-11
CN7-15

CN6-12
CN7-17
CN6-13

PFM SPEED1
PFM SPEED2
PFM ENA

CHPSW1
CHPSW2

CN3-1
CN3-5

DCM2PCB

RCL

RSW

RPCCL

FCL-U

RLDSW-M

PFM

RLDSW-L

PS-U

FCL-L

BYPTIMSW

BYP

CCL

RCL

RLDSW-U

RWCL-U

PS-M

FCL-M

PS-L

BYPRSW

RWCL-M

RWCL-L

*1

*1

*1

Figure 1-3-11 Block diagram of the paper feed section

1-3-9

Paper Feed Drive

The paper feed motor drives the paper feed rollers through electromagnetic clutches. When the feed
clutch is off and the roll winding clutch is on, the paper spool reverses to pull back the roll leading
edge the home position.

Paper Roll and Original Width Detection

Two sensors, paper size switches 1 and 2, detect the roll width. The original width is also detected by
two sensors, original size switches 1 and 2. Depending on the sensor status and UP setting, the
machine can detect the widths of 17.0”, 22.0” 34.0 (Engineering) or 18.0”, 24.0”, 36.0” (Architecture).
The paper leading edge switch is used only to detect the leading edge of roll paper.

Roll End

When the pulse disk on the roll winding clutch shaft stops rotation while the paper feed motor is on,
the machine detects a roll end condition. If the paper leading edge sensor is on when roll end is
detected, the cut ter clutch is energized to cut the p aper.

Upper Feed Clutch

Pulse Disk

Upper Roll Winding

Clutch

Paper Feed Motor

Middle Feed Clutc h

Middle Roll Windin g Clutch

Lower Feed Clutch

Pulse Disk

Pulse Disk

Original Size Switch1

Original Size Switch 2

Upper Paper Lea ding Edge Detect ion S witch

Middle Paper Leading Edge Detection Switch

Upper Paper Size Switch1

Lower Paper Size Sw itch

Lower Paper Lea ding Edge Detecti on S witch

Lower Roll Wind ing Clutch

Upper Paper

Size Switch

Lower Paper

Size Switch

1-3-9-1

Paper Transport

The by-pass registrati on clutch and the by- pass registration switch are used to contr ol the paper feed
timing.
For roll feeding, the feed clutch, roll paper conveying clut ch, reg istration clutch, and registration switch
control the paper feed timing. The paper feed length is measured by the registration sensor on time.
Initially, the paper feed motor is slightly faster than the drive motor which drives the pre-transfer drive
roller. This is to make a buckle between the registration roller and the pre-transfer drive roller. This
buckle absorbs the vibration when the paper is cut, to prevent jitter at the image transfer section. After
a buckle is made, the paper feed motor speed becomes the same as the drive motor speed.

Cutter Unit

The paper feed motor drive is transmitted to the cutter clutch through gears and a timing belt. The
rotary cutter rotates when the cutter clutch is energized. Initially, the cutter is in the home position, and
the cutter functions as a paper guide in this position. After the paper leading edge enters the c utter
unit, the cutter moves to the cutting ready position. After the paper is cut, the cutter returns to the
home position. Paper transportation does not stop during cutting.

Cutter Clutch

Roll Paper Conve yi ng Clutch

Feed Clutch

Cutting Ready Po s ition

Interrupted

Not Interru p te d

Cutter Home Position

Registratio n Clutch

By-Pass Registration Clutch

Cutter Blade

Home Position

Cutting Ready Posit ion

1-3-9-2

340

Winding operation of paper roll

The leading edge of the paper in the roll unit is first fed to the home position (copy ready
position) by the winding operation, where it is ready for copying.

• After the following operations, if the leading edge of the paper roll is not at the home
position, the winding operation for that roll unit will be performed.

1) After pressing the all clear/reset key.

2) After performing the auto clear function.

3) After changing the paper feed position with the paper source key.

4) One minute after a copy cycle ends and the ready lamp (copy ready indicator) lights.
(If any key is pressed after the ready lamp is lit, another minute will be counted after
the key press.)

5) After opening/closing the right cover (cycling safety switch 3), the main body
(cycling safety switches 4 and 5), or the upper rear cover (cycling safety switch 6).

• After the following operation, the winding operation for all the roll units will be performed.
(Winding starts with the lowest roll unit.)

1) After opening/closing the front covers (cycling safety switches 1 and 2).

• With the roll paper leading edge detection switch off

Off

PFM

RLDSW-U

FCL-U

On

Off

On

a

On

b

100 ms

Off

Timing chart 1-3-1 Winding operation for the first roll unit (1)

a The paper feed motor (PFM) and the upper feed clutch (FCL-U) turn on, and the paper

is conveyed in the feed direction.

b The upper feed clutch (FCL-U) and the paper feed motor (PFM) are turned off 100 ms

after the upper roll paper leading edge detection switch (RLDSW-U) is turned on, and
the leading edge of the paper stops at the home position (copy ready position).

• Winding operation for the 2nd and 3rd roll units is performed similarly.

1-3-10

340

• With the roll paper leading edge detection switch on

Off

PFM

RWCL-U

RLDSW-U

FCL-U

On

On

a

Off

On

Off

b

On

c

100 ms

Off

Timing chart 1-3-2 Winding operation for the first roll unit (2)

a The paper feed motor (PFM) and the upper roll winding clutch (RWCL-U) are turned on,

and the paper starts to wind.

b After the upper roll paper leading edge detection switch (RLDSW-U) turns off, the upper

roll winding clutch (RWCL-U) turns off and the upper feed clutch (FCL-U) turns on, and
the paper is conveyed in the feed direction.

c 100 ms after the upper roll paper leading edge detection switch (RLDSW-U) turns on,

the upper feed clutch (FCL-U) and the paper feed motor (PFM) turn off, and the leading
edge of the paper stops at the home position (copy ready position).

• Winding operation for the 2nd and 3rd roll units is performed similarly.

1-3-11

340

(1-1) Bypass paper feed

Paper insertion


BYPRSW: On

BYPTIMSW: On



Original insertion


OLDSW: On

OTDSW: On

BYPTIMSW: Off

Off

Off

e

Off

Off

Off

PFM

BYPRCL

OLDSW

BYPRSW

OTDSW

BYPTIMSW

PSYNC

signal

On

1.75 s

On



750 ms

ab

On

On

Timing chart 1-3-3 Bypass paper feed

Off

574 ms

On

d

On

450 ms

c

Potential buildup completed.
Primary original feed completed.
Shading correction completed.


With the paper inserted before the original.


200 ms

Off

a 1.75 s after the bypass registration switch (BYPRSW) is turned on by inserting paper into

the bypass table, the paper feed motor (PFM) and the bypass registration clutch
(BYPRCL) turn on, and feeding of the inserted paper starts.

b 750 ms after the bypass timing switch (BYPTIMSW) turns on, the bypass registration

clutch (BYPRCL) turns off, and the paper stops at the copy ready position.

c Potential buildup, primary original feed and then shading correction are completed. 450

ms after these secondary paper feed start conditions are satisfied, the PSYNC signal
turns on.

d The bypass registration clutch (BYPRCL) turns on to convey the paper to the transfer

section.

e 200 ms after the paper is conveyed to the transfer section and the bypass timing switch

(BYPTIMSW) turns off, the bypass registration clutch (BYPRCL) turns off, and the paper
feed operation is completed.

1-3-12

(1-2) Roll unit paper feed

Original insertion

OLDSW: On



OTDSW: On

RSW: On

CHPSW: On

OLDSW: Off

340

RSW: Off

CHPSW: Off

PFM

RCL

CCL

OLDSW

RSW

RPCCL

PCSW

OTDSW

FCL-U/M/L

CHPSW1, 2

OFCL

PSYNC

signal

a

On

Off

e

574 ms

d

On

On

78 P

On

c

On

375 ms

On

b

On

On

450 ms 600 ms



Off

1 s

Off

On

Potential buildup completed.
Primary original feed completed.
Shading correction completed.


Timing chart 1-3-4 Roll unit paper feed

On

Off

Off

h

200 ms

Off

Off

g

f

a 1 s after the original is inserted and the original trailing edge detection switch (OTDSW)

is turned on, the paper feed motor (PFM), the paper feed clutch for currently selected roll
unit [the upper/middle/lower feed clutches (FCL-U/M/L)], the roll paper conveying clutch
(RPCCL), and the registration clutch (RCL) are turned on to start feeding the paper in
the selected roll unit.

b The paper turns the registration switch (RSW) on. After 375 ms, the paper feed clutch

[upper/middle/lower feed clutch (FCL-U/M/L)], the roll paper conveying clutch (RPCCL),
and the registration clutch (RCL) are turned off and the paper stops. The cutter clutch
(CCL) is then turned on and the cutter starts to move to the ready position and primary
paper feed is completed.

c After the cutter home position switches (CHPSW 1 and 2) are turned on, the cutter clutch

(CCL) is turned off and the cutter stops at the ready position.

1-3-13

340

d Potential buildup, primary original feed and then shading correction are completed. 450

ms after these secondary paper feed start conditions are satisfied, the PSYNC signal is
turned on.

e The roll paper conveying clutch (RPCCL) and registration clutch (RCL) turn on to start

secondary paper feed.

f 78 pulses (PFM FG pulses) after the original leading edge detection switch (OLDSW)

turns off, the cutter clutch (CCL) is turned on and the paper is cut.

g After the cutter home position switches (CHPSW1 and 2) are turned off, the cutter clutch

(CCL) is turned off and the cutter stops at the home position. At the same time, the roll
paper conveying clutch (RPCCL) turns off.

h 200 ms after the registration switch (RSW) is turned off, the registration clutch (RCL) is

turned off to complete secondary paper feed.

1-3-14

340

(2) Main charger section

The main charger section is comprised of the drum, the drum potential sensor (DPS), the
main charger assembly and the main charger grid as shown in Figure 1-3-12.
The drum is electrically charged uniformly by means of a grid to form a static latent image
on the surface.
The drum potential sensor measures the dark potential of the drum surface.

2

Figure 1-3-12 Main charger section

1 Drum
2 Drum potential sensor (DPS)
3 Charger wire (tungsten wire)

3

1

4

5

4 Main charger assembly
5 Main charger grid

1-3-15

340

1

2

3

4

5

7

6

8

Figure 1-3-13 Main charger section (Main charger assembly)

1 Right main charger lid
2 Screw
3 Washer
4 Charger wire (tungsten wire)

CN6-17
CN7-23
CN6-19

MC REM
GRID CONT
MC ALARM

5 Left main charger lid
6 Main charger terminal
7 Charger spring
8 Main charger shield

3
4
5

Grid

1-3-16

MHVT

MPCB

Figure 1-3-14 Block diagram of the main charger section

Drum

Block Diagram Description

3.534 seconds after the drum motor starts, MCREM signal turns on and the main high voltage
transformer applies approximately 6 kV to the charge corona wire. Grid voltage depends on the pulse
width at CN7-2. When a charge corona leak occurs, the MC ALARM signal is sent to the main PCB
and SC302 is displayed.

To prevent toner scattering caused by sudden changes in the drum voltage and development bias
voltage, voltage is change in steps. The development bias voltage and the grid voltage are increased
in several synchronized steps, to minimize the difference in voltage between the drum and the
development roller.

After the copy operation is finished, the grid voltage and bias voltage are decreased in several steps.

1-3-16-1

340

DM

DRM

OTDSW

ESW

MHVT

GRID CONT

DB CONT

Potential buildup completed.

OTDSW: On ESW: On

a

On

2.3 s

On

b

400 ms

400 ms



3.534 s

On

Off

3.534 s

c

On

ESW: Off

Off

3 s

400 ms
600 ms

400 ms

d

Off

Off

e

1.6 s

Timing chart 1-3-5 Operation of the main high-voltage transformer

a When the original is inserted, the original trailing edge detection switch (OTDSW) is

turned on. After 2.3 s, the drive motor (DM) and drum motor (DRM) are turned on.

b 3.534 s (1 turn of the drum) after the drive motor (DM) and drum motor (DRM) are turned

on, the main high-voltage transformer (MHVT) is turned on to start main charging. The
grid voltage (GRID CONT) and developing bias voltage (DB CONT) are controlled
stepwise to increase the drum potential gradually.

c The drum potential reaches 870 V DC and the developing bias voltage (DB CONT) step-

up control ends. After 3.534 s (1 turn of the drum), potential buildup is completed.

d 3 s after copying is completed and the eject switch (ESW) is turned off, the grid voltage

(GRID CONT) and developing bias voltage (DB CONT) are controlled stepwise to
decrease the drum potential gradually.

e When the grid voltage (GRID CONT) step-down control ends, the main high-voltage

transformer (MHVT) is turned off and main charging ends.

1-3-17

Drum Dri v e Mechanism

The dru m is driven by the drum motor through an idle gear . The gea r of the drum f lange transmit s the
drum ro tation to the cleaning brus h and the cleaning spiral . T his machine use s an OPC drum of 90mm
diamet er .

There is an anti-condensation heater under the drum. The heater stays on while the main switch is off.

OPC Drum

Cleaning Brus h

Drum Drive Gear

Cleaing Spiral

Drum Motor

1-3-17-1

340-3

Drum surface potential correction

The grid control voltage (GRID CONT) is determined based on the target value set by
simulation 35 to maintain the drum surface potential around the developing section to
870 V DC.

• Correction timings

1) When any of the safety switches are turned off and on.

2) When the power plug is removed and reinserted.

3) When the main switch is turned off and on.

• Drum surface potential correction flow chart

Start.



The grid voltage is controlled stepwise to increase the 
drum surface potential gradually.


Dark potential is stabilized (maximum data is reached).


The drum potential sensor output is sampled 20 times 
and average value V2 is calculated.


The drum potential sensor output is sampled 20 times 
and average value V3 is calculated.


After 3.534 s (1 turn of the drum)


After 200 ms


1-3-18

Yes

Yes

V1 – 4 ≤ V2, V3 ≤ V1 + 4


V1 – 16 ≤ V2 < V1
V1 < V3 ≤ V1 + 16


V1 – 16 ≤ V3 < V1
V1 < V2 ≤ V1 + 16


The grid control voltage (GRID 
CONT) is determined based on 
V1, V2 and V3.


End.


No

No

Yes

V1: Drum potential sensor output value set 
 by simulation 35 for the drum surface 
 potential of 870 V DC.

V2: Average of sampled drum potential 
 sensor output values
V3: Average of sampled drum potential 
 sensor output values


No No

Is this the 10th correction?


C-551 “Dark potential correction 
problem” is triggered.






Yes

(3) Exposure and original feed section

6

5

7

8

9

0!

Figure 1-3-15 Exposure and original feed section

4

3

%

^

2

@

340

1

$

#

1 Original insertion guide
2 Front upper original roller
3 Middle upper original roller
4 Contact glass
5 Original holder rear guide
6 Rear upper original roller
7 Original feed rear guide
8 Rear lower original roller

Exposure is accomplished by scan exposure method with a moving original. A fluorescent
lamp is used as the light source. While being conveyed across the contact glass by the
rollers, the original is exposed by the fluorescent light and the exposed image is read by the
CIS (contact image sensor).
The fluorescent lamp heater (FLH) is installed on the fluorescent lamp (FL) to improve the
temperature characteristics which maintains the temperature of the fluorescent lamp to
approximately 40°C/104°F. The CIS reads the reflection of the fluorescent lamp (FL) light
on the middle upper original roller (white reference) to maintain the intensity constant.
The original is fed by the rotation of the front/middle/rear upper original rollers and the front/
rear lower original rollers. These rollers are controlled by the original leading edge detection
switch (OLDSW), the original trailing edge detection switch (OTDSW), and the original feed
clutch (OFCL). The original feed motor (OFM) drives the exposure section.

9 Original feed rear light shielding plate
0 Fluorescent lamp (FL)
! Fluorescent lamp heater (FLH)
@ Front lower original roller
# Original feed front light shielding plate
$ Original feed front guide
% SLA (SELFOC lens array)
^ CIS (contact image sensor)

1-3-19

Origin al Feed Mechani s m

Origin al is fed by origin al upper ro llers and original lower r ollers , which ar e dr iven by t he original feed
motor. The original feed clutch controls the rollers movement according to the sensors.

In the syncro-cut function, the length of the original is detected by the original trailing edge detect
sensor on time.

Orignal Trailing Edge Detect Sensor

Original Upper Roller

Original Leadin g Ed ge

Detect Sensor

Original Low er Roller

Original Feed Clutch

Original Feed M otor

Original Lower Rear Roller

1-3-19-1

340

a
b
c

OFM

CN2-1

CN2-10

CN2-2

CN2-11

CN2-3

CN2-12



CN2-13

DCM2PCB

INPCB

CN1-2

FLH REM

CN2-6

CN1-1




FLH

CN2-1

~

FL

FLTH

OTDSW

d
e
f

g

DCM2PCB TXD/RXD

d
e

DCM2PCB RXD/TXD

f
g

CN5-5

OLDSW

OFCL

FL CONT
FL REM

FLH REM

GS

GS

CN2-14
CN3-12
CN4-7A
CN3-13

MPCB

CN3-30
CN3-31

CN3-32
CN3-33

CN7-22
CN6-18

CN4-13B

CN6-6

OPPCB

OFM SPEED1

a

OFM ENA

b

OFM SPEED2

c

CN3-23
CN3-24
CN3-25

Figure 1-3-16 Block diagram of the exposure and original feed section

1-3-20

340

OLDSW: On

OTDSW: On

FL

On

OLDSW

a

On

On

OFM

OTDSW

Forward

Stop

Reverse

OFCL

640 ms

Timing chart 1-3-6 Operation of the exposure and original feed section

OTDSW: Off

1 s

On

c

500 ms

Off

d

b

On

Off

Secondary paper feed startSecond sheet secondary feed start

Shading correction start


OTDSW: Off

OTDSW: On

e

ff'

200 ms

On On

On

48 ms 48 ms

Off

Off

On

gg

Roll unit paper feed, multiple copying (2 sheets).


OTDSW: Off

k

1325 ms

Off

Off

e'

200 ms

500 ms

h

500 ms

Off

On

j

i



OTDSW: Off

Off

Off

'

a 640 ms after the original is inserted and the original leading edge detection switch

(OLDSW) is turned on, the original feed motor (OFM) starts to rotate forward and the
original feed clutch (OFCL) is turned on to start conveying the original.

b After the original is conveyed and the original trailing edge detection switch (OTDSW)

is turned on, the original feed clutch (OFCL) is turned off and the original stops at the copy
ready position.

c 1 s after the original trailing edge detection switch (OTDSW) is turned on, the CIS

(contact image sensor) starts shading correction and the fluorescent lamp (FL) lights.

d As soon as the secondary paper feed starts, the original feed clutch (OFCL) is turned on

and the original is conveyed across the contact glass for exposure.

e 500 ms after original exposure is completed and the original trailing edge detection

switch (OTDSW) is turned off, the original feed motor (OFM) is turned off.

f 200 ms after the original feed motor (OFM) is turned off, it starts to rotate in reverse to

return the original.

g When the original trailing edge detection switch (OTDSW) is turned off, the original feed

clutch (OFCL) is turned off and, after 48 ms, the original feed motor (OFM) is turned off
to complete original return operation.

h 500 ms after original return operation is completed, the original feed motor (OFM) starts

to rotate forward for the exposure for the second copy, and the original feed clutch
(OFCL) is turned on to convey the original.

i When the original is conveyed and the original trailing edge detection switch (OTDSW)

is turned on, the original feed clutch (OFCL) is turned off and the original stops at the copy
ready position.

j As soon as the secondary feed of the second sheet starts, the original feed clutch (OFCL)

is turned on and the original is conveyed across the contact glass for exposure for the
second copy. The original feed motor (OFM) and original feed clutch (OFCL) then repeat

e to g to return the original.

k 1325 ms after original exposure is completed and the original trailing edge detection

switch (OTDSW) is turned off, the fluorescent lamp (FL) is turned off.

1-3-21

340

(4) CIS and LPH section

In the CIS and LPH section, the CIS reads the original image exposed by the fluorescent
lamp (FL) and the drum surface is irradiated by the LPH to form a static latent image on it.

4

Figure 1-3-17 CIS and LPH section

1 SLA (SELFOC lens array)
2 LPH (LED printhead)

3

1

3 Fluorescent lamp (FL)
4 CIS (contact image sensor)

2

Contains 1 and 3.

1-3-22

340-1

CIS

LPH

5 V DC

GND

ISUPCB

LPHROMPCB

LPHPSPCB

FL CONT
FL REM

CN11
CN17

CN22

CN21

MPCB

CN7-22
CN6-18

INPCB

CN1-1

CN1-2

CN2-6

~




FL

CN2-1

Figure 1-3-18 Block diagram of the CIS and LPH section

1-3-23

340-1

Original image reading

The CIS (contact image sensor) consists of four channels of 3712 phototransistors. The
original image is read by 14592 phototransistors along a line of the width of A0 (934 mm),
and its analog data is sent to the ISU PCB (ISUPCB).

Original image


1 line


SLA (SELFOC 
lens array)

Channel 1


1, 2, 3 14592

Channel 2


CIS (contact image sensor)


Channel 3


Channel 4


Phototransistors

Figure 1-3-19 Original image reading

Static latent image formation

The LPH (LED printhead) consists of 14592 LEDs which are turned on and off based on the
image data read by the CIS to form a static latent image on the drum surface line by line.
Toner adheres only to the areas irradiated by the lit LEDs, so the image is formed.

LPH (LED printhead)

1,2,3 14592

SLA (SELFOC lens array)



1 line


LED

Drum

1-3-24

Figure 1-3-20 Static latent image formation

340

OFM

FL

OLDSW
OTDSW

Forward

Stop

Reverse

OFCL

OSYNC

signal

PSYNC

signal

OLDSW: On

On

640 ms

OTDSW: On

1 s

On

a

On

On

On

Off

c

b

Original and paper secondary feed start
Image reading start


Shading correction start

450 ms

OTDSW: Off

d

Off

e

Off

Off

450 ms

1325 ms

Timing chart 1-3-7 Image reading and formation

a 1 s after the original is conveyed and the original trailing edge detection switch (OTDSW)

is turned on, the CIS (contact image sensor) starts shading correction and the
fluorescent lamp (FL) lights.

b The original feed clutch (OFCL) is turned on to start secondary original feed. At the same

time, the fluorescent lamp (FL) starts exposure and the CIS starts to read the original
image.

c 450 ms after the original feed clutch (OFCL) is turned on, the OSYNC and PSYNC

signals are turned on and, in synch with these signals, the original image is processed
and the LPH forms a static latent image, respectively.
OSYNC signal: original leading edge synchronization signal
PSYNC signal: image formation synchronization signal

d 450 ms after the original trailing edge detection switch (OTDSW) is turned off, the

OSYNC and PSYNC signals are turned off to end image reading and formation.

e 1325 ms after original exposure ends and the original trailing edge detection switch

(OTDSW) is turned off, the original feed motor (OFM) and original feed clutch (OFCL)
are turned off. At the same time, the fluorescent lamp (FL) is turned off.

1-3-25

340

CIS correction

• Shading correction

Shading correction is carried out to correct the fluctuation in the fluorescent lamp (FL)
intensity and variations in the sensitivity between the sensor elements constituting the CIS.
If shading correction does not end within 30 s from its start, an original jam (J-05) is
indicated. If shading correction fails to end six times successively after the original is
reinserted, service call code C-300 is triggered.

Middle upper original roller 

Start.



(white reference)



CIS black reference value is created 

(black shading).



With the fluorescent lamp off, the 
average of the sensor read-in data is 
calculated for each channel.


Is the average read-in 

value below A0H?



Yes

CIS white reference value is created 

(white shading).



With the fluorescent lamp lit, the aver-
age of the sensor read-in data on the 
middle upper original roller (white 
reference) is calculated for each 
channel (see Figure 1-3-21).


Is the average read-in 

value above 80H?



Yes

No

No

SLA

Fluorescent 
lamp (FL)


CIS

Figure 1-3-21 White shading

The CIS read-in data is corrected based 
on the black and white reference values 
while the original image is read in.


End.


1-3-26

340

• AGC processing (gray level correction)

The tone of the image is reproduced by dividing the CIS image read-in value into 256 levels.
If the absolute white level is assumed to be 5.0 V and the absolute black level 0 V, the range
of the actual image read-in value is narrower than the range from 0 to 5.0 V, so the tone of
the reproduced image is affected. AGC processing (auto gain control) corrects the image
read-in value to reproduce gray levels more accurately.

Absolute white level
(5.0 V)

AGCHMAX 
(4.0 V)

AGCLMIN
(0.8 V)

Absolute black level 
(0 V)

Before AGC processing


Divided into 256 levels.


After AGC processing


VREFH 
(4.0 V + correction 
value)


VREFL 
(0.8 V + correction 
value)


Figure 1-3-22 AGC processing

Example: If the maximum white reference value (AGCHMAX) read by the CIS is 4.0 V and

the minimum black reference value (AGCLMIN) is 0.8 V, the range of the image
read-in value is narrower than the range between the absolute white level (5.0
V) and absolute black level (0 V). In such a case, the read-in value cannot be
divided into 256 levels and the tone of the reproduced image is affected. AGC
process corrects VREFH to 4.0 V, VREFL to 0.8 V and the correction value to 0
so that the read-in value can be divided into 256 levels to reproduce the tone of
the image more correctly.

• γ (gamma) correction

There are slight differences in the black-level read-in values between the four channels of
the CIS. Gamma correction can be made by executing simulation 120 so that an even image
output level is obtained.

1-3-27

340-1

(5) Developing section

The developing section is comprised of the developing unit assembly and the toner hopper
assembly. The developing unit assembly is comprised of the developing roller and doctor
blade which form a magnetic brush, and the developer paddle and developer spiral roller
which mix the developer. The toner hopper assembly is installed on the top of the developing
unit assembly to supply toner to the developing unit assembly and is comprised of the toner
feed roller and the toner agitation rod.

0

8

9

7

!

@

#

$

Figure 1-3-23 Developing section

1 Developing roller
2 Doctor blade
3 Developing unit thermistor (DTH)
4 Toner sensor (TNS)
5 Upper developing unit stay
6 Front hopper stay
7 Developing unit partition

TM

TNS

DTH

6

5

4

3

2

1

8 Toner feed roller
9 Toner agitation rod
0 Hopper lid
! Rear hopper stay
@ Developing unit housing
# Developer spiral roller
$ Developer paddle

CN2-18

CN2-2

1-3-28

DBHVT

DB REM
DB CHG
DB CONT

CN4-3B
CN4-4B
CN2-19

CN4-1A
CN4-2A

MPCB

3
4
5

Figure 1-3-24 Block diagram of the developing section

Development Unit Drive

The development unit is driven by the drive motor through a timing belt. The development paddle
moves the developer from left to right, and the development spiral moves the developer from right to
left (as v iewed from the oper ation side). Th is distri butes the developer evenly in the de v elopme nt unit.

The development thermistor and the toner sensor are located in the center of the development unit.

Development Paddle

Development Spir al

Drive Motor

Development Roller

1-3-28-1

340-1

Forming the magnetic brush

The developer flows by the rotation of the developing roller and the magnetic brush is formed
on pole N1. The height of the magnetic brush is set by the gap between the doctor blade
and the developing roller. The developing bias voltage (650 V DC) which is output from the
developing bias high-voltage transformer (DBHVT) is applied to the developing roller to
improve the image contrast. When the drum surface potential reaches 0 V after completion
of copying, the developing bias voltage is switched to –100 V DC to prevent toner and carrier
from adhering to the drum.

5

4

3

2

A

1

N2

6

7

A (gap between doctor blade and developing roller):

0.55

to 0.65 mm around the center

0.7 to 0.75 mm at both ends

Figure 1-3-25 Forming the magnetic brush and agitation of the developer

1 Developing roller
2 Doctor blade
3 Developing unit partition
4 Toner feed roller

N1: 900 × 10–4 ± 70 × 10–4T
N2: 600 × 10–4 ± 60 × 10–4T
S1: 750 × 10–4 ± 70 × 10–4T
S2: 750 × 10–4 ± 70 × 10–4T
S3: 600 × 10–4 ± 60 × 10–4T

5 Toner agitation rod
6 Developer spiral roller
7 Developer paddle

S3

60°

75°

S1

80°

S2

60°

N1

85°

1-3-29

340

Temperature compensation of the toner sensor output

Temperature compensation of the toner sensor (TNS) output value is applied by the
following formula.
The output values from the toner sensor (TNS) and the developing unit thermistor (DTH)
are input to the main PCB (MPCB). The main PCB samples the two input values at 8 ms
intervals. If two of three successive sampled input values are the same, this value is used
as one input value.

X = TS – K (TH – D26)

where X: control input (V, toner sensor output value after temperature compensation)

TS: actual toner sensor output (V)

K: temperature compensation coefficient (0.005 V/deg: TH > 26°C/79°F,

0.014 V/deg: TH < 26°C/79°F)

TH: temperature of the developing unit (°C/°F, detected temperature of the

developing unit thermistor)

D26: reference temperature (26°C/79°F)

A change in temperature TH – D26 based on the reference temperature (26°C/79°F) is
multiplied by temperature compensation coefficient K to obtain the temperature compensation
value; this is then subtracted from actual toner sensor output TS. Because the rate of
increase in the toner sensor output value is high when the temperature of the developing
unit is greater than 26°C/79°F, the main PCB compensates the toner sensor output
following the above formula, so as to lower the output. Because the rate of decrease in the
toner sensor output value is high when the temperature of the developing unit is less than
26°C/79°F, the main PCB compensates to increase the output.

1-3-30

340

Toner sensor output correction based on the copy count

The toner sensor (TNS) output is corrected by the following formula based on the copy count
(copy distance).

X = KM + TS

where X: control input value (V, toner sensor output value after copy count correction)

M: copy distance after execution of simulation 60 (m)

TS: actual toner sensor output (V)

K: distance correction coefficient (0.00021 V/m)

Control input value (V)


B

A

TS

Figure 1-3-26

A The copy distance count is cleared during developer setting (simulation 60).
B Until the copy distance reaches 1000 m, the actual toner sensor output value is corrected

by the formula as the copy distance increases.

C When the copy distance exceeds 1000 m, the actual toner sensor output value is

corrected with a constant value of +0.21 V.

C

0.21 V

10000

Copy distance (m)


1-3-31

340

Toner density control

Toner sensor output voltage (V)


Toner empty high level

Toner empty level

Message requesting toner 
to be replenished

Add toner indictor on

3 min





0.351 V

0.234 V

Toner control level



AB CD

Figure 1-3-27 Toner density control

A The value set while simulation 60 (developer setting) is performed is used as the toner

control level (initial output value for the toner control sensor). Toner feed motor (TM) on/
off control is based on this reference value.
If the temperature- and count-corrected toner sensor output value exceeds the toner
control level, the toner feed motor is turned on for 0.5 s to supply toner from the toner
hopper to the developing unit assembly. (The toner feed motor can be turned on only
when the developing unit assembly is driven, i.e. the drive motor is on.)
If the toner sensor output value does not drop during this 0.5 s period, the toner feed
motor is turned on for another 0.5 s, and this operation is repeated until the toner sensor
output value becomes lower than the toner control level.

B If the toner sensor output value rises further and remains 0.234 V or more above the toner

control level for 10 s, the toner empty level is detected and toner feed aging operation
is carried out. When the toner sensor output value reaches the toner control level, aging
is performed for 3 minutes after toner replenishing ends (toner feed motor off). If the
toner sensor output value does not reach the toner control level after 3 minutes of toner
feed aging, toner empty condition is detected and the add toner indicator on the
operation panel lights.

C When the toner sensor output value is 0.351 V or more above the toner empty level, the

toner empty high level is detected and the message requesting toner to be replenished
is shown on the display, inhibiting copying.

D When toner is replenished to the toner hopper and the toner sensor output value reaches

the toner control level, aging is performed for 3 minutes and then copying is enabled.

1-3-32

Toner Density Control [cont...]

If solid black copies are made continuously, toner supply from the toner hopper cannot keep up with
toner consumption and toner near end will be falsely indicaed. In this case, if “Single” has been
selected in SP 67, toner is supplied after every copy job, and the toner density will automatically
recover to the normal level (This prevents false toner near end detection, but users need to wait after
every copy job). If “Continuation” has been selected in SP67, toner is supplied only after the fusing
section, right center door or upper rear cover is opened and closed.

1-3-32-1

340

(6) Transfer/separation section

The transfer/separation section is comprised of the transfer charger assembly, the pre­transfer roller, and the separation claws as shown in Figure 1-3-28.

3

2

1

4

6

5

Figure 1-3-28 Transfer/separation section

1 Separation claw solenoid (SSOL)
2 Tungsten wires
3 Pre-transfer upper inner guide
4 Pre-transfer pulley
5 Pre-transfer outer guide
6 Pre-transfer roller

CN6-6

CN4-1B
CN4-2B

CN3-3

TC REM
SC REM
ST ALARM

87

CN1-1
CN1-2
CN1-3

!

@

0

9

7 Transfer charger
8 Separation charger
9 Transfer charger assembly
0 Separation claws
! Separation guide
@ Separation pulley

Drum

TC SC

SSOL

STHVT

MPCB

Figure 1-3-29 Block diagram of the transfer section

1-3-33

Block Diagram Description

The transfer & separation high voltage transformer applies the transfer and separation voltages. The
transfer and separation triggers are applied from CN4-1B and CN4-2B. The transfer voltage is about
dc –5.3 kV and the separation voltage is about ac 5.6 kV and dc 40 V.

When transfer or separation charge leakage occurs, the ST ALARM signal is sent to the main PCB,
and SC401 is displayed.

The transfer and separation voltages are constant. The voltages are adjusted in the factory and they
should not be changed in the field.

1-3-33-1

340

The transfer charger assembly is divided into the transfer charger which transfers the toner
image formed on the drum to the paper, and the separation charger which removes the
paper from the drum. Transfer charging and separation charging are performed by applying
high voltage which is output from the ST high-voltage transformer (STHVT) to both ends of
each tungsten transfer charger and separation charger wires. The separation claws are
installed to ensure paper separation.

1
2

3

6

5

7

8

9

4

#

@

Figure 1-3-30 Transfer charger assembly

1 Left transfer charger lid
2 Left transfer seal
3 Charger spring
4 Transfer charger left housing
5 Tungsten wire (for transfer

and separation charger)

6 Right transfer charger lid

1-3-34

!

7 Right transfer seal
8 Screw
9 Washer
0 Transfer charger right housing
! Transfer inner shield
@ Transfer outer shield
# Transfer wire

0

Separation Claw (Pick-off Paw l) Mechanism

During stand-by , the separation c laws are not in cont act with t he drum surface. 450 ms after the drum
potential step control is finished, the se paration claw solenoid is energized and the claws m ov e up to
the drum.

After that, when the paper c onveying switch detects t he leading edge of paper, the solen o id is
de-energized .

Separation Claw Solenoid

Separation Claw

1-3-34-1

340

OTDSW: Off

On

b

c

On

PCSW: On PCSW: Off

Off

On
Off

d

1680 ms

e

Off

f

Off

450 ms

Off

800 ms

Off

OTDSW

PCSW

SSOL

THVT

SHVT

DM

DB CONT

PSYNC

signal

OTDSW: On



On

2.3 s

a

944 ms

1704 ms

On
On

450 ms

Potential buildup completed.
Primary original feed completed.
Shading correction completed.


Timing chart 1-3-8 Operation of the transfer/separation section

a 2.3 s after the original is inserted and the original trailing edge detection switch (OTDSW)

is turned on, the drive motor (DM) turns on and, at the same time, separation charging
(SHVT) starts.

b 994 ms after the PSYNC signal is turned on, the separation claw solenoid (SSOL) is

turned on.

c 1704 ms after the PSYNC signal is turned on, transfer charging (THVT) starts.
d The moment the paper conveying switch (PCSW) is turned on, the separation claw

solenoid (SSOL) is turned off.

e 1680 ms after the PSYNC signal is turned off, transfer charging (THVT) ends.
f 800 ms after the developing bias step-down cotrol is completed, separation charging

(SHVT) ends.

1-3-35

340-1

(7) Cleaning section

Cleaning is performed by the blade cleaning method and the cleaning fur brush. The
cleaning section is comprised of the cleaning blade and the cleaning fur brush which remove
the residual toner adhering to the drum after transfer, and the cleaning unit spiral which
collects and sends toner to the waste toner tank.
The cleaning fur brush rotates always in contact with the drum surface and prevents the
toner scraped off the drum by the cleaning blade from dropping inside of the machine. Other
foreign matter such as paper fragments adhering to the surface of the drum are also
removed by the brush.
When the waste toner tank becomes full, the overflow sensor (OFS) is turned
message requesting the waste toner tank to be checked appears on the display on the
operation panel, and copying is inhibited.

2

1

3

off

and a

4

1-3-36

Figure 1-3-31 Cleaning section

1 Cleaning blade
2 Cleaning unit cover
3 Cleaning housing
4 Cleaning fur brush

7

6

5

5 Cleaning solenoid (CSOL)
6 Cleaning unit spiral
7 Lower cleaning blade

Toner Collection Mechanism

During stand-by , the cleaning bl ade is not in contac t with the drum sur f ac e. During copying, the
cleaning solenoid is e nergized and the cleaning blade is pr essed aga inst the drum surface.

When the toner disposal tank becomes full, the toner overflow switch turns off and a message is
displayed for the user to replace the tank. The messag e is displayed when the wei ght of the us ed
toner be c omes about 1,200 g.

The cleaning unit is connected to the toner disposal tank through the toner collection pipe. When the
toner pi pe is pushed down t o disconn ec t it from the cleaning unit, the shutter is closed by tension from
a spring to prevent used toner from falling.

Toner Ove r fl o w

Cleaning Blade

Waste Toner Tank

Detection Sw itch

Cleaning Solenoid

Toner Disposal Tank

Spring

Shutter

Toner Collect ion P ipe

1-3-36-1

340

CN6-5
CN6-4

CN3-7

CN3-8

MPCB

CSOL 1
CSOL 2

TDT DSW

OFS

Figure 1-3-32 Block diagram of the cleaning section

CSOL

1-3-37

340

OTDSW: On OTDSW: Off

Off

Off

10 min

1 s 1 s

c

1 s 1 s

Off

On

Off

d

1 s

Off

On On

On

OTDSW

DM

CSOL 1

CSOL 2

On

1.3 s

On

On

1 s

a

On

b

Timing chart 1-3-9 Operation of the cleaning solenoid

The cleaning solenoid (CSOL) is controlled by signals CSOL 1 and CSOL 2.

a 1.3 s after the original is inserted and the original trailing edge detection switch (OTDSW)

is turned on, signals CSOL 1 and CSOL 2 are turned on and the cleaning solenoid
(CSOL) is turned on.

b 1 s after the cleaning solenoid (CSOL) is turned on, the CSOL 1 signal is turned off. The

cleaning solenoid (CSOL) stays on.

c 10 minutes after copying is completed and the drive motor (DM) is turned off, the CSOL

2 signal is turned off and the cleaning solenoid (CSOL) is turned off. (If the drive motor
is turned back on for the next copy cycle within 10 minutes after it was turned off, a is
repeated.)

d 1 s after the cleaning solenoid (CSOL) is turned off, the CSOL 1 and CSOL 2 signals are

turned on and off at intervals of 1 s and the cleaning solenoid (CSOL) is turned on twice.

1-3-38

340

(8) Static eliminator section

The static eliminator section is comprised of the two cleaning lamps as shown in Figure
1-3-33. The post-transfer lamp (RTL) is to eliminate unnecessary charge, and the pre­charging lamp (PCHL) is to eliminate the residual charge after transfer.

Post-transfer lamp....... Since the transfer charger has been turned on before the latent

static image on the drum reaches the transfer charger, this lamp
eliminates the unnecessary charge generated by the transfer
charger and prepares for the next main charging (copy operation).

Pre-charging lamp ....... Eliminates the residual charge on the drum after the toner is

removed in the cleaning section to prepare for the next copy.

Pre-charging lamp (PCHL)


Post-transfer lamp (RTL)



Figure 1-3-33 Static eliminator section

1-3-39

340

MPCB

OTDSW

DM

PCHL

RTL

CN6-8

CN4-12B
CN4-12A

RTL REM
PCHL REM

OPPCB

CN5-6
CN5-7

Drum

CN6-7

Figure 1-3-34 Block diagram of the static eliminator section

OTDSW: On

On

a

2.3 s

On

On

On



OTDSW: Off

Off

PCHL

b

RTL

Off

Off

Off

Timing chart 1-3-10 Operation of the static eliminator section

a After the drive motor (DM) is turned on, the pre-charging lamp (PCHL) and the post-

transfer lamp (RTL) are turned on.

b After copying operation, the drive motor (DM) is turned off. Then the pre-charging lamp

(PCHL) and the post-transfer lamp (RTL) are turned off.

1-3-40

(9) Fixing section

98

7

340

156

2

3

›

‹

¤

)

⁄

0

!

@

Figure 1-3-35 Fixing section

1 Fixing heater M (H1)
2 Fixing heater S (H2)
3 Oil roller
4 Heat roller
5 Fixing unit thermal switch 1 (FTSW1)
6 Fixing unit thermal switch 2 (FTSW2)
7 Fixing unit upper partition
8 Fixing unit thermistor 1 (FTH1: near

the center of the heat roller)

9 Fixing unit thermistor 2 (FTH2: right

end of the heat roller)

0 Fixing unit cover
! Fixing unit middle front guide
@ Separation pulleys

(

&*

^%$# 4

# Fixing unit front guide
$ Fixing unit lower partition
% Front lower removal cover
^ Press roller
& Fixing unit thermistor 3 (FTH3: near

the center of the press roller)

* Fixing unit thermistor 4 (FTH4: right

end of the press roller)

( Lower eject guide
) Press roller separation claw
⁄ Eject roller
¤ Eject pulley
‹ Upper eject guide
› Separation claw

1-3-41

Oil Supp ly Me c ha nism

The oil roller, which contacts the heat roller applies oil to the heat roller surface. The heat roller gear
drive is transmitted to the oil roller gear t hr ough an idle gear , and the oil roller rotates in the same
direction as the heat roller.

Drive Mechanism

An independent dc motor drives the fusing unit. The drive is transmitted to the heat roller gear,
throug h idle gears. The heat roller gear tr ansmits the drive to the ex it roller gear and oil rolle r gear
throug h idle gears.

Oil Roller

Heat Roller

Fusing Pressure Mechan ism

Two springs apply fusing pressure through the pressure arm.

Spring

Pressure Arm

1-3-41-1

Fixing Unit Release Mechanism

The fixing section can be released from the drum section to remove misfed paper in the fusing section.

When the left and right levers are pulled, the hooks are released and the fixing unit can be pulled
toward s the operator’s si de.

There are two safety switches in the left and right lock positions. When one of these switches is off,
the 24V l ine is cut and a cover open message is displayed.

Safety Switc h

Fixing Unit Open Mechanism

Release Lever

To remove misfed paper be tween th e heat roller and the press roller, th e upper part of the fix ing unit
can be opened. When the release button is pushed, the two lock arms are released and the upper unit
opens because o f t he tension from the s pr ing.

Release Button

Lock Arm

Release Lever

1-3-41-2

Fixing Entrance Guide

The fixing entrance guide controls the angle of the paper leading edge, so that the paper is fed
properly between the heat roller and press roller without creasing or misfeeding. The height of the
center of the guide can be changed by changing the number of spacers to suit various types of paper.

Fusing Entrance Guide

1-3-41-3

340-3

The fixing section is comprised of the parts shown in Figure 1-3-35. After the transfer
operation, the paper is conveyed to the fixing section and passes between the heat roller
and the press roller. A constant pressure is applied between the heat roller and the press
roller by the fixing press spring and the toner transferred is fixed on the paper by the heat
and pressure applied from each roller.
Fixing heater M (H1) heats the center of the heat roller and fixing heater S (H2) heats the
ends of the heat roller.
The oil roller cleans the surface of the heat roller to prevent the paper from wrapping around
the heat roller.
After fixing, the paper is separated from the heat roller by the separation claws and ejected
to outside of the machine via the eject roller and the eject pulley.

MPCB

CN4-8B
CN4-7B
CN4-3A

CN7-6
CN7-7

CN2-5

CN2-6

CN2-7

CN2-8

CN2-10

CN3-16

CN3-17

CN4-5A
CN4-5B

SSR2 REM
SSR1 REM
SSR3 REM

FDM REM
FDM CLK

PRY1

CN3-3
CN3-4
DCM1PCB

FFM REM
FFM H/L

SSR2 SSR1

CN5-1
CN5-2
CN5-3
CN5-4

+

FG

FG

FTSW1

FTSW2

FR*

*

SSR3

−

FDM

FTH1

FTH2

FTH3

FTH4

ETTH

ESW

FPS

FFM-R

H2

H1



1-3-42

FFM-L

*For 230 V, 50 Hz models only.

Figure 1-3-36 Block diagram of the fixing section

Heating and temperature control of heat roller and press roller

• Heat roller temperature control 1

Fixing unit thermistor 1 (FTH1) detects the surface temperature around the center of the
heat roller and fixing unit thermistor 2 (FTH2) detects the surface temperature of the right
end of the heat roller.
If the temperature TPRD (surface temperature around the center of the press roller) detected
by fixing unit thermistor 3 (FTH3) becomes less than TPTH, fixing heaters M and S (H1 and
H2) are turned on to heat the heat roller. Control temperature T is controlled by the following
formula.

Control temperature T = THCON + k (TPTH – TPRD)
When (TPTH – TPRD) < 0, T = THCON.

THCON: heat roller control temperature

k: temperature compensation coefficient (standby: 0.33, copying: 1)

TPTH: press roller temperature threshold value

TPRD: fixing unit thermistor 3 (FTH3) temperature (surface temperature around

the center of the press roller)

Heat roller temperature


T

HCON

Heat roller control temperature


340

T

PTH

90˚C/194˚F
80˚C/176˚F




Standby StandbyCopy start

Figure 1-3-37 Fixing temperature control

Press roller surface temperature




Copy end


1-3-43

340

• Heat roller temperature control 2

When the temperature T

detected by the external temperature thermistor (ETTH) is as

ETTH

in the table, the control temperatures are changed to prevent poor fixing. If the ambient
temperature is below 15°C/59°F, fixing is not performed sufficiently, and if greater than
30°C/86°F, the image may be blurred.

External temperature thermistor

detection temperature

≤ 15°C/59°F 145°C/293°F 165°C/329°F

T

ETTH

15°C/59°F < T

< 30°C/86°F 165°C/329°F 155°C/311°F

ETTH

Primary stabilization

temperature

Secondary stabilization

temperature

30°C/86°F ≤ TETTH 165°C/329°F 155°C/311°F

The heat roller control temperature and the press roller temperature threshold value must
be changed as follows depending on the paper used (plain paper, tracing paper, or film) to
prevent poor fixing.

External tempera-

ture thermistor

detection

temperature

T

≤ 15°C/59°F

ETTH

15°C/59°F < T

ETTH

< 30°C/86°F

30°C/86°F

≤ T

ETTH

Heat roller control

temperature

Plain

paper

155°C/

311°F

150°C/

302°F

145°C/

293°F

Tracing

paper

150°C/

302°F

145°C/

293°F

140°C/

284°F

Film

155°C/

311°F

150°C/

302°F

145°C/

293°F

Press roller temperature

threshold value

Plain
paper

105°C/

221°F

105°C/

221°F

105°C/

221°F

Tracing

paper

100°C/

212°F

100°C/

212°F

100°C/

212°F

Film

105°C/

221°F

105°C/

221°F

105°C/

221°F

1-3-44

340

• Press roller temperature control 1

If the surface temperature of the press roller is less than its minimum value or the surface
temperature between the heat roller side and on the opposite side is different, fixing
problems may occur. Therefore, the following control is performed to keep the surface
temperature of the press roller constant.
In ready status, if the fixing unit thermistor 3 (FTH3) temperature (temperature around the
center of the press roller) becomes less than 80°C/176°F, fixing heaters M and S (H1 and
H2) are turned on. The fixing drive motor (FDM) is then turned on at low speed to increase
the surface temperature of the press roller. When the temperature of fixing unit thermistor
3 (FTH3) reaches 90°C/194°F, fixing heaters M and S (H1 and H2) and the fixing drive motor
(FDM) are turned off. By repeating these operations, the surface temperature of the press
roller is maintained between 80°C/176°F and 90°C/194°F.

• Press roller temperature control 2

When copies are made with small-size paper, the press roller temperature becomes higher
at the ends where no paper passes than around the center where paper passes. This
causes the ends of the press roller to swell, reducing the paper conveying force around the
center.
After copying is completed, the fixing unit thermistor 3 (FTH3) temperature (temperature
around the center of the press roller) is compared to the fixing unit thermistor 4 (FTH4)
temperature (temperature at the right end of the press roller), and the fixing drive motor
(FDM) speed is corrected in proportion to the temperature difference to prevent the paper
conveying speed from decreasing in the fixing unit.

Fixing unit thermistor 2


Fixing unit thermistor 4

Heat roller


Press roller


Fixing unit thermistor 1


Fixing heater M


Fixing heater S

Fixing unit thermistor 3


Figure 1-3-38 Heat roller and press roller temperature detection

1-3-45

Paper Exit Mechanism

After the image is fixed, the copy paper is transported to the copy tray by the exit rollers. There are 13
separation claws (hot roller strippers) which help paper to separate from the heat roller.

Separation Claw

Upper Exit Roller

Lower Exit Roller

1-3-46