Ricoh FT5035-S Service Manual ft5035

SECTION 1

OVERALL MACHINE INFORMATION

13th January 1995 SPECIFICATIONS

1. SPECIFICATIONS

Configuration: Desktop Copy Process: Dry electrostatic transfer system Originals: Sheet/Book Original Size: Maximum A3/11" x 17" Copy Paper Size: Maximum

A3/11" x17" (Paper trays)

Minimum

A5/81/2" x 51/2" sideways (Paper trays) A4/11" x 81/2" sideways (LCT) A6/51/2" x 81/2" lengthwise (By-pass)

Duplex Copying: Maximum

A3/11" x 17"

Minimum

A5/81/2" x 51/2" (sideways)

Copy Paper Weight: Paper tray:

52 ~ 128 g/m2, 14 ~34 lb (A153, A155, and A156 copiers) 64 ~ 90 g/m2, 17 ~ 24 lb (A157, A159, and A160 copiers)

By-pass:

52 ~ 157 g/m2, 14 ~42 lb

LCT:

52 ~ 128 g/m2, 14 ~ 34 lb

Duplex copying:

64 ~ 105 g/m2, 17 ~ 24 lb

Overall

Information

Reproduction Ratios: 4 Enlargement and 6 Red uction

A4/A3 Version LT/DLT Version

200%

Enlargement

Full size 100% 100%

Reduction

1-1

141% 122% 115%

93% 82% 75% 71% 65% 50%

200% 155% 129% 121%

93% 85% 77% 74% 65% 50%

SPECIFICATIONS 13th January 1995

Power Source: 120V/60Hz:

More than 12 A (for North America)

220V ~ 240V/50Hz:

More than 7 A (for Europe)

220V/50Hz:

More than 7 A (for Asia)

110V/60Hz:

More than 14 A (for Taiwan)

220V/60Hz:

More than 7 A (for Saudi Arabia, Philippines)

Power Consumption:

A153, A155, and A156 copiers A157, A159, and A160 copiers

Copier Only Full System Copier Only Full System

Maximum 1.45 KW 1.50 KW 1.45 KW 1.50 KW

Copying 1.00 KW 1.00 KW 0.80 KW 0.80 KW Warm-up 0.90 KW 0.92 KW 0.90 KW 0.92 KW Stand-by 0.16 KW 0.19 KW 0.15 KW 0.17 KW

1 0.15 KW 0.17 KW 0.14 KW 0.16 KW

Energy

Saver

Auto Off 0.02 KW 0.04 KW 0.02 KW 0.04 KW

2 0.13 KW 0.15 KW 0.12 KW 0.13 KW 3 0.12 KW 0.14 KW 0.09 KW 0.10 KW 4 0.11 KW 0.12 KW 0.07 KW 0.08 KW 5 0.09 KW 0.11 KW 0.05 KW 0.06 KW 6 0.07 KW 0.09 KW – –

NOTE: 1) Full System: Copier + ADF + Paper Tray Unit + 20 Bin S/S

2) Energy Saver: Se e SP 1-105-002

3) Auto Off: See SP5-305

Noise Emission:

A153, A155, and A156 copiers A157, A159, and A160 copiers

Copier Only Full System* Copier Only Full System*

1. Sound Power Level

Copying 66 dB(A) 68 dB(A) 61 dB(A) 67 dB(A) (L Warm-up 41 dB(A) 41 dB(A) 39 dB(A) 40 dB(A) (L Stand-by 41 dB(A) 41 dB(A) 39 dB(A) 40 dB(A) (L

2. Sound Pressure Level at the operator position

Copying 58 dB(A) 57 dB(A) 54 dB(A) 56 dB(A) (L Warm-up 33 dB(A) 27 dB(A) 32 dB(A) 27 dB(A) (L Stand-by 33 dB(A) 27 dB(A) 32 dB(A) 27 dB(A) (L

NOTE: The above measurements are to be made according to ISO 77 79 .

* : Full System: Copier + ADF + Paper Tray Unit +10 Bin S/S .

WA) WA) WA)

PA) PA) PA)

1-2

13th January 1995 SPECIFICATIONS

Dimensions:

Width Depth Height

A153 copier 1030 mm (40.6") 655 mm (25.8") 606 mm (23.9") A157 copier 900 mm (35.5") 655 mm (25.8") 606 mm (23.9")

A155 and A156

copiers

A159 and A160

copiers

1258 mm (49.6") 655 mm (25.8") 606 mm (23.9")

1128 mm (44.5") 655 mm (25.8") 606 mm (23.9")

Measurement Conditions

1) With by-pass feed table closed

2) With platen cover and copy tray attached

3) With LCT cover closed Weight:

Weight

A153 copier About 70 kg (154.2 lb) A155 copier About 78 kg (171.9 lb) A156 copier About 82 kg (180.7 lb) A157 copier About 67 kg (147.7 lb) A159 copier About 75 kg (165.4 lb) A160 copier About 80 kg (176.4 lb)

Overall

Information

Zoom: From 50% to 200% in 1% steps Copying Speed (copies/minute):

A153, A155, and

A156 copiers

A157, A159, and

A160 copiers

A4 sideways/

11" x 8

1/2"

35 20/19 22

27 15/14 17

A3/11" x 17" B4/8

Warm-Up Time A153, A155, and A156 copiers:

Less than 110 second s (2 0 ° C)

A157, A159, and A160 copiers:

Less than 80 seconds (20°C)

First Copy Time:

Paper Feed Station

1st Tray 5.2 s (except for A156) 5.9 s (except for A160)

2nd Tray 5.7 s 6.6 s

By-pass 4.8 s 5.6 s

LCT 5.0 s 5.9 s

A153, A155, and A156 copiers A157, A159, and A160 copiers

A4/11" x 8

1/2" (sideways)

1/2" x 14"

Note: In A156 and A160 copiers, the 2nd tray in th e above tab le is called the

1st tray (see Installation - Paper Feed St at ion Definition).

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SPECIFICATIONS 13th January 1995

Copy Number Input: Ten-key pad, 1 to 999 (count up or count down) Manual Image Density

7 steps

Selection:

Automatic Reset: 1 minute is the standard set ting; it can be

changed to a maximum of 999 seconds or no auto reset by SP mode.

Copy Paper Capacity:

Paper Tray By-pass Feed LCT

A153 copier About 500 sheets x2 About 40 sheets – A155 copier About 500 sheets x2 About 40 sheets About 1000 sheets A156 copier About 500 sheets x1 About 40 sheets About 1000 sheets A157 copier About 250 sheets x2 About 40 sheets – A159 copier About 250 sheets x2 About 40 sheets About 1000 sheets A160 copier About 250 sheets x1 About 40 sheets About 1000 sheets

Duplex Tray Capacity [A156/A160]:

50 sheets (30 sheets for A3/11"x17" 81 ~ 105g/m2, 21.5 ~ 27.9 lb paper)

Toner Replenishment: Cartridge exchange (415 g/cartridge) Optional Equipment: • Platen cover

• Document feeder

• Paper tray unit with two paper trays

• Paper tray unit with three paper trays

• 10 bin micro sorter

• 20 bin mini sorter

• 10 bin sorter stapler

• 20 bin sorter stapler

• Sorter adapter (required when installing 20

bin mini sorter, 10 bin sorter stapler, or 20 bin sorter stapler for A1 57, A1 59 , an d A1 60 copiers)

• Key counter

• Tray heater

• Optical anti-condensation heater

• Original length sensor for 11 " x 15" size

paper (only for LT/DLT version)

• ADS sensor for particular types of red orig ina l

1-4

13th January 1995 MACHINE CONFIGURATION

2. MACHINE CONFIGURATION

2.1 COPIER

Overall

Information

1-5

MACHINE CONFIGURATION 13th January 1995

2.2 OPTIONAL EQUIPMENT

1-6

13th January 1995 MECHANICAL COMPONENT LAYOUT

3. MECHANICAL COMPONENT LAYOUT

– A156 copier –

1098

Overall

Information

4 3

38 37

36 35 34

33 32

16 17

18 19 20

24 23

NOTE: 1. The A153 copier is the same as the A15 6 cop ier exce pt that the

A153 does not have a duplex tray or an LCT.

2. The A155 copier is the same as the A15 6 cop ier exce pt that the A155 does not have a duplex tray.

1-7

MECHANICAL COMPONENT LAYOUT 13th January 1995

– A160 copier –

4 3

38 37

35 34 33 32

1098

13 14

15 16

17 18 19

NOTE: 1. The A157 copier is the same as the A16 0 cop ier exce pt that the

A157 does not have a duplex tray or an LCT.

2. The A159 copier is the same as the A16 0 cop ier exce pt that the A159 does not have a duplex tray.

1-8

13th January 1995 MECHANICAL COMPONENT LAYOUT

1. 3rd Mirror

22. Vertical Transport Rollers

2. 2nd Mirror

3. 1st Mirror

4. Exposure Lamp

5. Lens

6. Quenching Lamp

7. Drum Cleaning Blade

8. Drum Charge Roller

9. 6th Mirror

10. OPC Drum

11. Erase Lamp

12. 4th Mirror

13. 5th Mirror

14. Toner Supply Unit

23. Paper Feed Roller The roller for A153/A155/A156 copiers is different from that for A157/159/160 copiers.

24. Friction Pad

25. Duplex Friction Roller

26. Duplex Feed Roller

27. Jogger Fence

28. Transfer Belt

29. Transfer Belt Cleaning Blade

30. Lower Paper Tray

31. End Fence

32. Entrance Rollers

33. Pick-off Pawls

Overall

Information

15. Pre-transfer Lamp

16. Development Unit

17. Registration Rollers

18. Feed Roller

19. Pick-up Roller

20. Separation Roller

21. Large Capacity Tray

34. Pressure Roller

35. Hot Roller

36. Junction Gate

37. Hot Roller Strippers

38. Transport Fan

1-9

PAPER PATH 13th January 1995

4. PAPER PATH

4.1 NORMAL COPYING

– A156 copier –

–A160 copier –

1-10

13th January 1995 PAPER PATH

4.2 DUPLEX COPYING

– A156 copier –

Overall

Information

– A160 copier –

1-11

ELECTRICAL COMPONENT DESCRIPTIONS 13th January 1995

5. ELECTRICAL COMPONENT DESCRIPTIONS

Refer to the electrical compone nt layou t an d the po int to point diag ram on the waterproof paper in th e pocket for symbols and index numbers.

Symbol

Printed Circuit Boards

PCB1 14

PCB2 12 PCB3 11 DC Power Supply Provides dc power.

PCB4 96 Main Motor Control Controls the rotation of the main motor. PCB5 1 PCB6 55 T High Voltage Supply Supplies high voltage to the transfer belt. PCB7 3

PCB8 8

PCB9 63

PCB10 6

PCB11 102

Motors

M1 88 Main Drives the main unit components. M2 79

M3 97

M4 86

M5 99 M6 94 Optics Cooling Fan 1 Removes heat from the optics unit.

M7 95

M8 89

M9 90

Index

No.

Description Note

Main Control Controls all copier functions both directly or

through other control boards.

AC Drive Provides ac power to the exposure lamp and

fusing lamps.

CB High Voltage Supply

Operation Panel Controls the LED matrix, and monitors the

Noise Filter (220 ~ 240 V machines only)

Duplex Control (Duplex machines only)

Liquid Crystal Display (A156 machines only)

LCT Interface (LCT machines only)

Toner Bottle Drive Rotates the toner bottle to supply toner to

Upper Tray Lift (A153/A155 machines only)

Lower Tray Lift (A153/A155/A156 machines only)

LCT Lift (LCT machines only)

Optics Cooling Fan 2 (A153/A155/A156 machines only)

Exhaust Fan 1 Removes the heat from around the fusing

Exhaust Fan 2 (A153/A155/A156 machines only)

Supplies high voltage to the drum charge roller and development roller.

key matrix. Removes electrical noise.

Controls the operation of the duplex tray.

Controls the guidance display and displays guidance for machine operation.

Interfaces the LCT control signal between the main board and the LCT.

the toner supply unit. Raises the bottom plate in the upper paper

tray.

Raises the bottom plate in the lower paper tray.

Lifts up and lowers the LCT bottom plate.

Removes heat from the optics unit.

unit. Removes the heat from around the fusing

unit.

1-12

13th January 1995 ELECTRICAL COMPONENT DESCRIPTIONS

Symbol

M10 92 M11 78 3rd Scanner Drive Drives the 3rd scanner (dc stepper motor).

M12 87 Lens Vertical Drive Shifts the lens vertical position. M13 77 Lens Horizontal Drive Shifts the lens horizontal position.

M14 58

M15 61

M16 60

Sensors

S1 27

S2 31

S3 51

S4 107

S5 29

S6 52

S7 106

S8 30

S9 100

S10 26

S11 28

Index

No.

Description Note

Scanner Drive Drives the 1st and 2nd scanners (dc stepper

motor).

Duplex Feed (Duplex machines only)

End Fence Jogger (Duplex machines only)

Side Fence Jogger (Duplex machines only)

By-pass Feed Paper Width

By-pass Feed Paper End

Upper Tray Paper End (Non-duplex machines only)

Upper Relay Detects the leading edge of paper from the

Upper Tray Upper Limit (A153/A155 machines only)

Lower Tray Paper End

Lower Relay Detects the leading edge of paper from the

Lower Tray Upper Limit (A153/A155/A156 machines only)

LCT Lower Limit (LCT machines only)

LCT Paper End (LCT machines only)

LCT Upper Limit (LCT machines only)

Drives the feed roller and moves the bottom plate up and down.

Drives the end fence jogger to square the paper stack.

Drives the side fence jogger to square the paper stack.

Informs the CPU what width paper is in the by-pass feed table.

Informs the CPU that there is no paper in the by-pass tray.

Informs the CPU when the upper paper tray runs out of paper.

upper tray to determine the stop timing of the upper paper feed clutch, and detects misfeeds.

Detects the height of the paper stack in the upper paper tray to stop the upper tray lift motor.

Informs the CPU when the lower paper tray runs out of paper.

lower paper tray to determine the stop timing of the lower paper feed clutch, and detects misfeeds.

Detects the height of the paper stack in the lower paper tray to stop the lower tray lift motor.

Sends a signal to the CPU to stop lowering the LCT bottom plate.

Informs the CPU when the LCT runs out of paper.

Sends a signal to the CPU to stop lifting the LCT bottom plate.

Overall

Information

1-13

ELECTRICAL COMPONENT DESCRIPTIONS 13th January 1995

Symbol

S12 28

S13 50

S14 53

S15 39

S16 20

S17 15

S18 24

S19 21 S20 45 Fusing Exit Detects misfeeds.

S21 16

S22 54

S23 43

S24 23

S25 13

S26 44

S27 19

S28 56

S29 57

S30 62

S31 59

S32 64

Index

No.

Description Note

Registration Detects the leading edge of the copy paper

to determine the stop timing of the paper feed clutch, and detects misfeeds.

Image Density (ID)

Toner Density (TD)

Lens Horizontal HP Informs the CPU that the lens is at the

Lens Vertical HP Informs the CPU that the lens is at the

Scanner HP Informs the CPU when the 1st and 2nd

3rd Scanner HP Informs the CPU when the 3rd scanner is at

Original Length-2 Detects the length of the original. This is one

Platen Cover Informs the CPU whether the platen cover is

Toner End Instructs the CPU to add toner to the toner

Auto Response Returns the operation panel display and exits

Transfer Belt ContactHPInforms the CPU of the current position of

Auto Image Density (ADS Sensor)

Original Width Detects the width of the original. This is one

Original Length-1 Detects the length of the original. This is one

Duplex Paper End (Duplex machines only)

Duplex Turn (Duplex machines only)

Duplex Entrance (Duplex machines only)

Side Fence Jogger HP (Duplex machines only)

End Fence Jogger HP (Duplex machines only)

Detects the density of various patterns on the drum during process control.

Detects the amount of toner inside the development unit.

horizontal home position.

full-size position.

scanners are at the home position.

the home position.

of the APS (Auto Paper Select) sensors.

up or down (related to APS/ARE functions). ARE: Auto Reduce and Enlarge

supply unit, and detects toner end conditions.

from the energy saver mode.

both the transfer belt unit and the drum charge roller unit.

Detects the background density of each original in ADS mode.

of the APS (Auto Paper Select) sensors.

of the APS (Auto Paper Select) sensors. Detects paper in the duplex tray.

Detects the trailing edge of the copy paper to determine the jogging timing, and detects misfeeds.

Detects misfeeds.

Detects the home position of the duplex side fence jogger.

Detects the home position of the duplex end fence jogger.

1-14

13th January 1995 ELECTRICAL COMPONENT DESCRIPTIONS

Symbol

S33 22

Switches

SW1 33

SW2 36

SW3 35

SW4 104

SW5 25

SW6 34

SW7 32

SW8 105

SW9 103 SW10 42 Main Supplies power to the copier. SW11 41

SW12 48

Magnetic Clutches

CL1 72 CL2 71 Development Drives the development roller.

CL3 93

CL4 73 Registration Drives the registration rollers. CL5 74 CL6 76 Relay Drives the relay rollers.

CL7 84

CL8 85

Index

No.

Description Note

Original Length (Option for N. American models)

By-pass Feed Table Detects whether the by-pass feed table is

Upper Tray (Non-duplex machines only)

Lower Tray Detects whether the lower paper tray is in

Tray Down (LCT machines only)

Upper Tray Paper Size (Non-duplex machines only)

Lower Tray Paper Size

Vertical Guide Set (Non-LCT machines only)

LCT Cover-1 (LCT machines only)

LCT Cover-2 (LCT machines only)

Front Cover Safety Cuts the ac power line and detects whether

Exit Cover Safety (A157/A159/A160 machines only)

Toner Supply Turns the toner supply roller to supply toner

Transfer Belt Contact Controls the touch and release movement of

By-pass Feed Starts paper feed from the by-pass feed

Upper Paper Feed (Non-duplex machines only)

Lower Paper Feed Starts paper feed from the lower paper tray.

Detects original length for 11" x 15" paper.

open or closed. Detects whether the upper paper tray is in

place or not.

place or not. Sends a signal to the CPU to lower the LCT

bottom plate. Determines what size of paper is in the

upper paper tray.

Determines what size of paper is in the lower paper tray.

Detects whether the vertical guide is open or not.

Detects whether the LCT cover is open or not.

Cuts the dc power line of the LCT lift motor.

the front door is open or not. Cuts the ac power line and detects whether

the exit cover is open or not.

to the development unit.

both the transfer belt unit and the drum charge roller unit.

table or LCT.

Starts paper feed from the upper paper tray.

Overall

Information

1-15

ELECTRICAL COMPONENT DESCRIPTIONS 13th January 1995

Symbol

Solenoids

SOL1 75

SOL2 91

SOL3 98

SOL4 80

SOL5 82

SOL6 81

SOL7 83

Lamps

L1 17

L2 65 L3 66 Secondary Fusing Provides heat to both ends of the hot roller.

L4 4

Index

No.

Description Note

LCT machines: LCT/By-Pass Pick-up Solenoid Non-LCT machines: By-pass Pick-up Solenoid

Junction Gate (Duplex machines only)

LCT Pick-up (LCT machines only)

Upper Tray Pick-up (A153/A155 machines only)

Lower Tray Pick-up (A153/A155/A156 machines only)

Upper Tray Separation (A153/A155 machines only)

Lower Tray Separation (A153/A155/A156 machines only)

Exposure Applies high intensity light to the original for

Main Fusing Provides heat to the central area of the hot

Pre-transfer Reduces the charge remaining on the drum

Picks paper up from the by-pass feed table. When paper is fed from the LCT, this solenoid assists SOL3.

Moves the junction gate to direct copies to the duplex tray or to the paper exit.

Picks up paper from the LCT.

Controls the up/down movement of the pick-up roller in the upper paper tray.

Controls the up/down movement of the pick-up roller in the lower paper tray.

Controls the up-down movement of the separation roller in the upper paper tray feed station.

Controls the up-down movement of the separation roller in the lower paper tray feed station.

exposure.

roller.

surface before transfer.

L5 5

L6 2

Heaters

H1 38

H2 46

Quenching Neutralizes any charge remaining on the

drum surface after cleaning.

Erase After exposure, this eliminates the charge on

areas of the drum that will not be used for the image.

Drum Turns on when the main switch is off to keep

the temperature around the drum charge roller at a certain level. Also prevents moisture from forming around the drum.

Optics Anti-condensation (option)

Turns on when the main switch is off to prevent moisture from forming on the optics.

1-16

13th January 1995 ELECTRICAL COMPONENT DESCRIPTIONS

Symbol

H3 37

Thermistors

TH1 69

TH2 70 TH3 47 Optics Monitors the temperature of the optics cavity. TH4 49

Thermofuses

TF1 68

TF2 67

TF3 18

Counters

CO1 40

CO2 N/A

Others

CB1 9

CC1 10 Choke Coil Removes high frequency current.

TR1 7

Index

No.

Description Note

Lower Tray (option)

Main Fusing Monitors the temperature at the central area

Secondary Fusing Monitors the temperature at the ends of the

Drum Charge Monitors the temperature of the drum charge

Main Fusing Provides back-up overheat protection in the

Secondary Fusing Provides back-up overheat protection in the

Exposure Lamp Opens the exposure lamp circuit if the 1st

Total Keeps track of the total number of copies

Key (option)

Circuit Breaker (220 ~ 240V machines only)

Transformer (220 ~ 240V machines only)

Turns on when the main switch is off to keep paper dry in the lower paper tray.

of the hot roller.

hot roller.

roller.

fusing unit.

scanner overheats.

made. Used for control of authorized use. The

copier will not operate until it is installed.

Provides back-up high current protection for electrical components.

Steps down the wall voltage to 100 Vac.

Overall

Information

1-17

DRIVE LAYOUT 13th January 1995

6. DRIVE LAYOUT

6.1 ALL MODELS

1 . Drum Drive Pulley

2. Drum Charge Roller Drive Gear

3. Transfer Belt Conta ct Clut ch Gear

4. Scanner Drive Motor

5. Scanner Drive Pulley

6. Transfer Belt Drive Gear

7. Fusing Unit Drive Gear

8. Main Motor

9. Main Pulley

10. Registration Clutch Gear

11. By-pass Feed Clutch Gear

12. Development Drive Clutch Gear

13. Toner Supply Clutch Gear

1-18

13th January 1995 DRIVE LAYOUT

6.2 A153/A155/A156

1. Upper Paper Feed Clutch Gear (A153/A155 only)

2. Lower Paper Feed Clutch Gear

3. Relay Clutch Gear

6.3 A157/A159/A160

Overall

Information

1. Upper Paper Feed Clutch Gear (A157/A159 only)

2. Lower Paper Feed Clutch Gear

3. Relay Clutch Gear

1-19

SECTION 2

DETAILED DESCRIPTIONS

13th January 1995 PROCESS CONTROL

1. PROCESS CONTROL

1.1 OVERVIEW

1.1.1 Copy Process around the Drum

2. EXPOSUR E

1. DRUM CHARGE

9. QUENCHING

8. CLEANING

3. ERASE

4. DEVELOPMENT

Detailed

Descriptions

ID SENSOR

PICK-OFF PAWLS

TRANSFER BELT

Fig. 1 Copy Process Around the Drum

1. DRUM CHARGE

In the dark, the drum charge roller gives a uniform negative cha rge to the organic photo-conduct ive (OPC) drum. The charge remains on th e surface of the drum because the OPC layer has a high electrical resistan ce in the dark. The amount of negative charge on the dru m is propo rtio na l to th e negative voltage applied to the drum charg e rolle r.

7. PAPER SEPARATION

5. PRE-TRANSFER LAMP

6. IMAGE TRANSFER

2-1

PROCESS CONTROL 13th January 1995

2. EXPOSURE

An image of the original is reflected onto the OPC drum surface via the optics assembly. The charge on the drum surface is dissipated in direct proportion to the intensity of the refle cte d light, thus producing an electrical latent image on the drum surface.

The amount of remaining charg e as a lat ent image on the drum depends on the exposure lamp intensity, which is co nt rolle d by the exposure lamp voltage.

3. ERASE

The erase lamp illuminates the areas of th e cha rge d dru m su rfa ce th at will not be used for the copy image. The resistance of the drum in the illuminated areas drops and the charge on those areas dissipates.

4. DEVELOPMENT

As a result of the development potential (the difference of charged voltage between the drum and the toner), ton er is att ract ed to the are as of the drum where the negative charge is greater than that of the toner, and the latent image is developed.

The development bias volt ag e ap plied to the developmen t rolle r shaft controls two things:

1) The threshold level fo r wh et he r t on er is attracted to the drum or whether it remains on the development roller.

2) The amount of toner to be attracted to the drum.

The higher the negative develo pme nt bias volt ag e is, th e less toner is attracted to the dru m surface.

5. PRE-TRANSFER LAMP (PTL)

The PTL illuminates the drum to remove almost all the negative charge from the exposed areas of the drum. This prevents the toner particles fro m bein g reattracted to the drum surf ace during paper separation and makes pa pe r separation easier.

2-2

13th January 1995 PROCESS CONTROL

6. IMAGE TRANSFER

Paper is fed to the area between the drum surf ace and the tran sfer belt at the proper time so as to align the copy paper and the develope d image on the drum surface. Then, the tran sfer bias roller applies a strong negative cha rge to the reverse side of the copy paper through the tran sfer belt. This negative charge produces an electrical fo rce which pulls the toner particles from t he drum surface on to the copy paper. At the same time , th e cop y pap er is electrically attracted to the transfer belt.

7. PAPER SEPARATION

Paper separates from the OPC drum as a result of the electrical attra ction between the paper and the transfe r belt . The pick-off pawls help separate the paper from the drum.

8. CLEANING

The cleaning blade remove s ton er rema ining on the drum after the image is transferred to the pa pe r.

9. QUENCHING

Light from the quenching lamp electrically neutralizes the charge on the dru m surface.

Detailed

Descriptions

2-3

PROCESS CONTROL 13th January 1995

1.1.2 Factors Affecting Process Control

Fig. 2 Process Control

In this copier, the fo llowin g items are controlled durin g th e copy process to maintain good copy quality:

• Exposure lamp voltage

• Drum charge roller voltage

• Development bias voltage

• Toner supply

The machine controls th e ab ove by monitoring the following electrical components:

• Operation panel (manual ID selection and reproduction ratio)

• ADS sensor

• TD sensor

• ID sensor

• Drum charge thermistor

• Paper size detecto rs

• RAM board (drum rotatio n time , SP mode data, and paper size da ta)

2-4

13th January 1995 PROCESS CONTROL

1.1.3 Process Control Procedures

This section outlines how the machine controls the copy process based on the inputs from various sensors.

Copy Image Control

This is how the machine adjusts copy processes based on settings input at the operati on panel.

- Manual ID Correction -

If the user inputs the imag e de nsit y manu ally, the machin e ad just s the exposure lamp voltage an d the development bias to achie ve th e selected image density.

- Reproduction Ratio Correction -

If the user selects a 116% or great er en larg ement ratio or a 50% reduction ratio, the machine corrects the development bia s to comp en sate for the loss in light intensity reaching the drum.

Detailed

Descriptions

- ADS Pattern Detection and ADS Correction -

If the user selects Auto Ima ge Density (ADS) mode, the machine monitors the output from the ADS sensor and ad just s the deve lop ment bias to compensate for variatio ns in ADS sensor response. This preven ts dirty background.

Every 1,000 copies, the machine calibrates the ADS sensor output by reading the ADS patt ern und er th e left scale of the exposure glass.

The ADS sensor must also be reca librated:

• If the drum is changed

• If the ID sensor is clean ed or chan ged

• If the exposure lamp or optics are cleaned or cha ng ed .

Image Density Control

This is how the machine corrects th e con centration of toner in the developer based on readings from the ID (Image Density) and TD (Ton er Den sity) sensors.

- VSP and VSG Detection/ID Correction -

The machine uses VSP and VSG rea din gs by the ID sensor, along with readings from the toner density sensor, to determine if the toner concentration in the deve lop er is at th e optimu m le vel.

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PROCESS CONTROL 13th January 1995

The amount of ton er supplied to the VSP pattern must remain constant. To ensure this, the mach ine app lies a correction to the develop men t bias for V SP patterns when combine d readings from the TD and ID sensors indicate that the carrier is ageing. This correction is called "ID Correction".

- Toner Supply -

There are three toner supply modes. Detect toner supply: Toner supply varies with paper size, the latest TD

sensor reading, and the latest VSP and VSG readings by the ID sensor. For example, toner supply will be increased if the toner weight rat io in th e developer is decreasin g, or if the most recent VSP pattern was detected as being relatively light.

Fixed supply mode: The toner supply remains constant, but can be adjuste d with an SP mode.

TD supply mode: Toner supply varies with TD sen sor outp ut . For example, if the toner weight ratio has decreased since TD sensor supply mode was selected, toner supply is increased.

Drum Potential Control

This is how the machine compensates for aging of the drum an d th e exposure lamp, and for the temperature around the drum charge roller.

- VR Pattern Detection and VR Correction -

As the drum gets older, the drum’s residual voltage grad ually increases due to electrical fatigue. Ligh t fro m t he expo sure lamp will not erase the increased residual voltage effe ctive ly a nd dirty ba ckgro un d will result .

Every 1,000 copies, part of the drum is developed with the VR pattern development bias. If the re is residu al voltage on the drum, this area of the drum will attract some toner, making a V R pattern. The ID sensor response to this pattern is compare d with the response of the ID sensor to a bare area of the drum. The higher the residu al volt ag e on the drum is, th e da rker th e VR pattern is. If the pattern is too dark, the drum will not be discharg ed sufficiently. As a result, the machine will increase the negative de velo pment bias to prevent dirty background. If it does, image density will drop. To prevent this, the machine will a lso incre ase the negative drum charge roller voltage.

(The VRP/VRG range to which the above mentioned bias and charg e corrections are applied may be shift ed to can cel the ef fe ct of ID correct ion.)

VR correction data must be reset by SP mode if the drum is chan ge d or if th e ID sensor is cleaned or replaced.

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13th January 1995 PROCESS CONTROL

- VL Pattern Detection and VL Correction -

This is how the machine adjusts the expo sure lamp voltage to compensate for the effects of drum wea r, dirty optics, and response of the drum to lig ht .

Every 1,000 copies, an imag e of the VL pattern under the left scale bracket is made on the drum. The machine compares the response of the ID sensor to this image with the response to a bare are a of the drum.

The exposure lamp voltage is adjust ed if there ha ve be en significant changes from the measurements made from when a new drum or lamp was installe d.

(The VLP/VLG range to which the abo ve men tioned lamp voltage adjustment is applied may be shifted to cancel the effect of ID correction .)

Initial VLP/VLG detection must be done by SP mode if a new drum is installed or if the exposure lamp is cleaned or replaced.

- T/H Correction -

The efficiency of tran sfer of charge from the drum charg e roller to the drum varies with the temperature near the dru m charg e rolle r. Also, the drum potential after cha rging varies with the accumula te d rotation time of the drum.

Detailed

Descriptions

A thermistor measures the temperature near the drum charge roller, and the CPU keeps track of how long th e dru m h as rot at ed for.

The machine adjusts th e dru m ch arg e roller voltage depending on the temperature and accumulated rotation time.

This section has provided an overview of all the proce ss cont rol procedures done by the machine. The next few pa ge s will exp lain each of th ese in more detail. At the end, there will be a summary.

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PROCESS CONTROL 13th January 1995

1.2 COPY IMAGE CONTROL

Copy image control adju sts the development bias and exp osure lamp voltage to take account of the repro du ction ratio and image densit y. The ima ge density is either selected by th e use r or det ect ed automa tically.

1.2.1 Manual ID Correction

If the user selects the image density man ua lly, th e selected manual ID level affects the exposure la mp volt ag e an d th e de velopment bias as follows.

- Exposure Lamp Voltage -

As the ID level increases from 1 to 7, the exposu re lamp voltage is increased as shown in the following table.

Table 1. Exposure lamp vol tage control by manua l ID level

ID Level Lamp Voltage

1 Vexp –4.0 V 2 Vexp –3.0 V 3 Vexp –1.5 V 4 5 Vexp +1.5 V 6 Vexp +4.0 V 7 Vexp +6.0 V

Vexp ±0.0 V

Vexp = Lamp voltage selecte d with SP4-001. It can be between 50 and 75 V. It is factory set, and varies from copier to copier.

- Development Bias -

The greater the nega tive voltage, the paler th e imag e on the drum. However, the development bias is adjust ed only at the extre me light and dark ends of the manual ID range.

Table 2. Development bias control by manua l ID level

ID Level Development Bias

1 +80 V 2 3 4 5 6 7 SP2-201-002 (see below)

±0 V ±0 V ±0 V ±0 V ±0 V

Note: The base developme nt bias volt age is -2 40 Volt s.

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ID Level

–320 (Lighter)

–240 (Darker)

–360 (Lightest)

13th January 1995 PROCESS CONTROL

For ID Level 7 (lightest copie s), th ere are fo ur possible development bias correction setting s tha t can be selected with SP2-20 1-0 02 , as sho wn be low.

Table 3. Lightest ID level developme nt bias (ID Leve l 7)

SP2-201-002 Setting Density

1 (Factory Setting) Normal –40 V

2 Dark 3 Lighter –80 V 4 Lightest –120 V

Dev. Bias

Correction Voltage

±0 V

In summary, the development bias at various ID level settings is shown below.

Development Bias Voltage

–320

SP2-201-002

–280

–240

–160

–280 (Normal)

1765432

for ID Level 7

Detailed

Descriptions

1.2.2 Reproduction Ratio Correction

At reproduction ratio s of 50 % an d 11 6% or g rea ter, the intensity of light reaching the drum from the origin al drops significantly, which could cause copies to become underexposed (too dark).

To compensate for th is, a de velopment bias correction voltage is applied as shown in Table 4. This correction incre ases the development bias volta ge , restoring the copy image densit y to normal.

Table 4. Reproduction ratio correction

Reproduction

Ratio (%)

181 ~ 200 –100 V 161 ~ 180 –80 V 142 ~ 160 –60 V 123 ~ 141 –40 V 116 ~ 122 –20 V 51 ~ 115

50 –30 V

Development Bias

Correction Voltage

±0 V

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