Ricoh FT4220.22 Service Manual FT4220

IMPORTANT SAFETY NOTICES

PREVENTION OF PHYS ICAL INJURY

1. Before disassembling or asse mblin g pa rts of the copie r and perip herals, make sure that the copier power cord is unplu gg ed.

2. The wall outlet should be near the copier an d easily accessible.

3. Note that some compo ne nt s of th e copier and the paper tray unit are supplied with electrical voltage even if the main switch is turned off.

4. If any adjustment or operat ion check has to be made with exterior covers off or open while the main switch is turned on, keep hands away from electrified or mechanically drive n comp on ents.

5. The inside and the met al parts of the fusing unit become extre mely ho t while the copier is operat ing . Be ca ref ul to avoid touching those components with your bare hands.

HEALTH SAFETY CONDITIONS

1. Never operate the copier without the ozon e filt er inst alle d.

2. Always replace the ozone filter with the specified one at the specifie d interval.

3. Toner and developer are non-toxic, but if you get either of them in your eyes by accident, it may cause temp ora ry e ye disco mfo rt. Try to remove with eye drops or flush with wat er as first aid. If un succe ssfu l, ge t med ical attention.

OBSERVANCE OF ELECTRICAL SAFETY STANDARDS

1. The copier and its peripheral must be installed and maintained by a customer service represen tative who has completed the training course on those models.

– CAUTION –

2. The RAM pack has a lithium battery which can explod e if hand led incorrectly, replace only with same RAM pack. Do not recharge, or burn this battery. Used RAM pack must be handle d in accordance with local regulations.

SAFETY AND ECOLOGICAL NOTES FOR DISP OS AL

1. Do not incinerate the toner cartridge or the used toner. Toner dust may ignite suddenly when exposed to open flame.

2. Dispose of used tone r, developer, and organic photoconductors according to local regulations. (These are non-toxic supplies.)

3. Dispose of replaced parts in acco rda nce with local regulations.

SECTION 1

OVERALL MACHINE

INFORMATION

1 May 1993 SPECIFICATIONS

1. SPECIFICATIONS

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

Minimum: A6/51/2" x 81/2" (lengthwise)

..... Manual an d casse tte feeds

A5/11" x 81/2" (sideways)

..... Paper tray feed

(Duplex Copying) A4/11" x 81/2" (sideways) Copy Paper Weight: Cassette feed: 52 to 157 g/m2 (14 to 42 lb)

Paper tray feed: 64 to 90 g/m2 (17 to 22 lb) Manual feed: 52 to 157 g/m2 (14 to 42 lb) Duplex: 58 to 104 g/ m2 (16 to 28 lb)

Reproduction Ratio: 2 Enlargement and 3 Red uction

A4/A3 version LT/LDG version

Enlargement 141%

122% Full size 100% 100% Reduction 93%

82% 71%

155% 129%

93% 74% 65%

Overall

Information

Zoom: From 50% to 200% in 1% steps Copying Speed: (A110 copier)

20 copies/minute (A4/11" x 8 1/2" sideways) 10 copies/minute (A3/11" x 17") (A111 copier) 22 copies/minute (A4/11" x 8 1/2" sideways)

11 copies/minute (A3/11" x 17") Warm-Up Time: Less than 60 seconds (at 20°C) First Copy Time: 5.9 seconds (A4/11" x 81/2" sideways for cassette

feed) Copy Number Input: Ten keys, 1 to 99 (count up)

1-1

SPECIFICATIONS 1 May 1993

Manual Image Density

7 steps Selection:

Automatic Reset: All input modes are reset 1 minute after the copier

is not in use; can also be set to 3 minut es or no

auto reset. Energy Saver Function: Saving the electricity consumption

(Manual or manual/auto) Paper Capacity: Cassettes: 500 sheets

Paper tray: 250 sheets

(A110 copier ... 1 paper tray) (A111 copier ... 2 paper trays)

Manual feed table: 50 sheets Toner Replenishment: Black: Cartridge exchange (370g/cartridge)

Color (red, blue, & green):

Cartridge exchange (310 g/ cart ridge)

Copy Tray Capacity: 250 sheets (B4/81/2" x 14" and smaller)

100 sheets (A3/11" x 17") Power Source: 1 10 V/ 60 Hz/ 15 A (fo r Taiwan )

115 V/ 60 Hz/ 15 A (for North America)

220/230/240 V/ 50 Hz/ 8 A (for Europe)

220 V/ 60 Hz/ 8 A (for Middle East)

(Refer to the serial numb er plate (rating plate) t o

determine the power source required by the

machine.) Power Consumption:

A110 copier A111 copier Maximum 1.2 kVA 1.3 kVA Warm-up 720 VA (average) 720 VA (average) Copy cycle 810 VA (average) 830 VA (average) Stand-by

(without energy saver function)

160 VA (average) 160 VA (average)

1-2

1 May 1993 SPECIFICATIONS

Dimensions:

Width Depth Height

Copier only A110 copier 672 mm (1130 mm)

26.5" (44.5")

A111 copier 672 mm (1130 mm)

26.5" (44.5")

Full system A110 copier 1149 mm

45.3"

A111 copier 1149 mm

45.3"

( ): when the cassette and platen cover are installed and the copy tray is extended.

600 mm

23.7" 600 mm

23.7"

410 mm (464 mm)

16.1" (18.3") 530 mm (584 mm)

20.9" (23.0") 513 mm

20.2" 633 mm

25.0"

Noise Emissions:

Maximum Copy cycle Stand-by Copier only less than 58 dB less than 55 dB less than 40 dB Full system less than 60 dB less than 58 dB less than 40 dB

Overall

Information

Weight:

A110 copier A111 copier

Copier only 55 kg (121.3 lb) 64 kg (141.1 lb) Full system 78 kg (172 lb) 83.5 kg (184 lb)

Optional Equipment and Machine Configu rat ion:

( ) Machine Code

Configuration Optional dc power supply unit (A525)

Main frame Optional equipment Required Not required

A110 copier 10 bin sorter (A490) O

Document feeder (A318) O Duplex unit (A491) O Color development unit (A313) O

A111 copier 10 bin sorter (A490) O

Document feeder (A318) O Duplex unit (A491) O Color development unit (A313) O

Other Optional Equ ipment:

• Key counter

• Universal cassette

• Optics anti-condensation heater

1-3

SPECIFICATIONS 1 May 1993

• Specifications are subje ct to change witho ut notice.

1-4

1 May 1993 COPY PROCESSES AROUND THE DRUM

2. COPY PROCESSES AROUND THE DRUM

2. EXPOSURE

1. DRUM CHARGE

3. ERASE

9. QUENCHING

4. DEVELOPMENT

Overall

Information

8. CLEANING

7. PAPER SEPARATION

5. PRE-TRANSFER LAMP (PTL)

6. IMAGE TRANSFER

1-5

COPY PROCESSES AROUND THE DRUM 1 May 1993

1. DRUM CHARGE

In the dark, the charge corona unit gives a uniform negative charge to the organic photoconductive (OPC) drum. The charge remains on the surface of the drum because the OPC drum has a high electrical resistance in the dark.

2. EXPOSURE

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

3. ERASE

The erase lamp illuminates the areas of the charged drum surface that 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

Positively charged toner is attracted to the negatively charged areas of the drum, thus developing the latent image. (The positive triboelectric charge is caused by friction between the carrier and toner particles.)

5. PRE-TRANSFER LAMP (PTL)

The PTL illuminates the drum to remove all negative charge from the exposed areas of the drum. This prevents the toner particles from being reattracted to the drum surface during paper separation and makes paper separation easier.

6. IMAGE TRANSFER

Paper is fed to the drum surface at the proper time so as to align the copy paper and the developed image on the drum surface. Then, a strong negative charge is applied to the back side of the copy paper, producing an electrical force which pulls the toner particles from the drum surface to the copy paper. At the same time, the copy paper is electrically attracted to the drum surface.

7. PAPER SEPARATION

A strong ac corona discharge is applied to the back side of the copy paper, reducing the negative charge on the copy paper and breaking the electrical attraction between the paper and the drum. Then, the stiffness of the copy paper causes it to separate from the drum surface. The pick-off pawls help to separate paper.

8. CLEANING

The cleaning brush removes most of the toner on the drum and loosens the remainder. Then the cleaning blade scrapes off the loosened toner.

9. QUENCHING

Light from the quenching lamp electrically neutralizes the surface of the drum.

1-6

1 May 1993 COPY PROCESS CONTROL

3. COPY PROCESS CONTROL

Image Density Control

Toner Density Detection

Residual Voltage (Vr) Detection

Between Copies (Nonimage area)

Grid Voltage Exposure Lamp

Voltage

Standard image density grid voltage (–920V) + Drum residual voltage (Vr) correction factor (SP67) +

Standard ID sensor grid voltage (–560V) + Vp correction factor (SP69)

–500 bolts (Fixed)

0 volt (Fixed) Exposure lamp turns

Base exposure lamp voltage

1. Manual mode [SP48]

2. ADS mode [SP48] and [SP34]

VL correction factor [SP61] and [SP57]

+ Drum wear correction factor (SP58) + Reproduction ratio correction factor

Same as image density control

off

Development Bias

Voltage

Base bias voltage

1. Manual mode

2. ADS mode [SP34]

+ Base bias voltage

adjustment factor

[SP37].....Black

[SP79].....Color

+ Drum residual voltage (Vr) correction factor (SP67)

Toner density adjustment factor

[SP33].....Black

[SP75].....Color

+ Vd correction factor (Black only) (SP64)

0 volt (Fixed) Full erase

–200 volts (Fixed) +

Base bias voltage adjustment factor

[SP37].....Black

[SP79].....Color

Erase Lamp

Depending on paper size and reproduction ratio

ID sensor pattern erase (Vsg detection: Full erase)

(All LEDs ON)

Full erase (All LEDs ON)

Overall

Information

+ Drum residual voltage (Vr) correction factor (SP67)

NOTE: a) Boxed items can be adju ste d by SP modes surrounded by square

brackets [ ].

b) Data which determines the correct ion factor can be observed by

SP modes surrounded by parenth esis ( ).

1-7

MECHANICAL COMPONENT LAYOUT 1 May 1993

4. MECHANICAL COMPONENT LAYOUT

1 2 3 4 5 6 7 8 9 10 11 12 13 14

35 34

33 32

15 16

1. Third Mirror

2. Second Mirror

3. First Mirror

4. Exposure Lamp

5. Ozone Filter

6. Cleaning Unit

7. Lens

8. Quenching Lamp (QL)

9. Charge Corona Unit

10. Sixth Mirror

11. Erase Lamp

12. OPC Drum

13. Development Unit

14. Toner Supply Unit

15. Optics Cooling Fans

16. 1st Feed Roller

17. Manual Feed Table

18. Pick-up Roller

222324252627282930

19. Separation Roller

20. 1st Relay Rollers

21. 2nd Relay Rollers (A111 copier only)

22. 2nd Feed Rollers (Semi-circular)

23. 3rd Feed Rollers (Semi-circular) (A111 copier only)

24. Registration Rollers

25. Pre-transfer Lamp (PTL)

26. Transfer and Separation Corona Unit

27. Pick-off Pawls

28. Cleaning Brush

29. Cleaning Blade

30. Pressure Roller

31. Hot Roller

32. Duplex Turn Guide (Option)

33. Exit Rollers

34. Hot Roller Strippers

35. Exhaust Blower

1-8

G20

G12

G13

G29: Duplex Transport Gear (Option)

1 May 1993 DRIVE LAYOUT

5. DRIVE LAYOUT

G11

G17 BP2 G16 TB1 G19 G18 G22 G23 G24

G26

G27

Overall

Information

G10

BP3

BP4

G14

G1: Main Motor Gear

G2: Relay Gear G18: Relay Gear

Gear

BP1: Timing Belt Pulley TB1: Timing Belt

TB2

BP5

Drum Fusing and Exit Section

Development Section

G28

G3BP1G15G33G32G31

G20: Relay Gear G21: Cleaning Drive Cleaning

G22: Relay GearG19: Drum Drive GearG3: Timing Belt Drive

G23: Relay Gear G24: Relay Gear

G29G25G21

BP2: Timing Belt Pulley

G16: Development CL Gear

G17: Toner Supply CL Gear

Toner Supply CL Toner Supply Unit

G25: Hot Roller Gear G26: Relay Gear

G27: Relay Gear

G28: Exit Roller Gear

Development UnitDevelopment CL Solenoid

1-9

TB2: Timing Belt

G32: Relay Gear

DRIVE LAYOUT 1 May 1993

Paper Feed Section

BP3: Timing Belt Pulley

G11: Registration CL Gear

Registration CL Registration Roller

1st Feed Station

1st Paper Feed CL Solenoid 1st Paper Feed Rollers

G4: Relay Gear G12: Relay Roller CL Gear G5: Relay Gear

G6: 1st Paper Feed CL Gear G7: Relay Gear G8: Paper Lift CL Gear Paper Lift CL G9: Paper Lift Gear G10: Sector Gear

2nd Feed Station Upper Relay Roller

G13: Upper Relay Roller Gear

Relay Roller CL

3rd Feed Station

(A111 copier only)

G14: Relay Gear

G15: 2nd Paper Feed CL Gear

2nd Paper Feed CL

2nd Paper Feed Roller

1-10

BP4: Timing Belt Pulley

BP5: Timing Belt Pulley Lower Relay Roller G31: Lower Relay Roller Gear

G33: 3rd Paper Feed CL Gear 3rd Paper Feed CL 3rd Paper Feed Roller

234

1 May 1993 ELECTRICAL COMPONENT LAYOUT

6. ELECTRICAL COMPONENT LAYOUT

Overall

Information

11 12

1. Scanner H.P. Sensor

2. Lens H.P. Sensor

3. Scanner Motor

4. Main Motor

5. Development Clutch Solenoid

6. Toner Supply Clutch

7. 4th/5th Mirror H.P. Sensor

8. Color Toner End Sensor

9. 4th/5th Mirror Motor

10. Pick-up Roller Release Solenoid

11. Manual Feed Table Switch

12. Color Switch

13. Paper Lift Clutch

14. 1st Paper Feed Clutch Solenoid

15. Registration Clutch

16. Right Cover Switch

17. Relay Roller Clutch

18. 1st Paper Size Switch

19. 1st Paper End Sensor

20. Relay Sensor (A111 copier only)

21. Paper Lift Sensor

22. Registration Sensor

23. Total Counter

24. Pre-transfer Lamp (PTL)

25. ID Sensor Board

26. Erase Lamp

27. Fusing Lamp

28. Quenchi ng Lamp (QL)

29. Auto Image Density Sensor

30. Fusing Thermistor

31. Toner Overflow Sensor

32. Fusing Thermofuse

33. Exit Sensor

34. Lens Motor

1-11

ELECTRICAL COMPONENT LAYOUT 1 May 1993

57 56

35. Platen Cover Closed Switch (A111 copier only)

36. Operation Panel Board

37. Original Length Sensor (A111 copier only)

38. Optics Thermoswitch

39. Exposure Lamp

40. Original Width Sensor (A111 copier only)

41. Cover Safety Switch

42. Main Switch

43. Exhaust Blower Motor

44. Drum Anti-condensation Heater

45. Main DC Power Supply Board

46. Option DC Power Sup ply Bo ard (A110 copier only)

47. Option Transformer (A110 copier only)

48. 3rd Paper Size Switches (A111 copier only)

49. Noise Filter Board (220/230/240 V only)

50. 2nd Paper Size Switches

51. Main Transformer

52. 3rd Paper End Sensor (A111 copier only)

53. AC Drive Board

54. 3rd Paper Feed Clutch (A111 copier only)

55. 2nd Paper End Sensor

56. 2nd Paper Feed Clutch

57. Main Motor Capacitor

58. Main Board

59. TC/SC Power Pack

60. CC/Grid/Bias Power Pack

61. Platen Cover Position Sen sor (A111 copier only)

62. Optics Cooling Fan Motors

1-12

1 May 1993 ELECTRICAL COMPONENT DESCRIPTIONS

7. ELECTRICAL COMPONENT DESCRIPTIONS

Symbol Name Function Index No.

Motors

M1 Main Motor Drives all the main unit components except

for the optics unit and fans. (115/220/230/240 Vac)

M2 Scanner Motor Drives the scanners (1st and 2nd). (dc

stepper)

M3 Lens Motor Moves the lens position according to the

selected magnification. (dc stepper)

M4 4th/5th Mirror Motor Move the 4th/5th mirror position according to

the selected magnification. (dc stepper)

M5 Optics Cooling Fan

Motor-1

M6 Optics Cooling Fan

Motor-2

M7 Exhaust Blower

Motor

Prevents built up of hot air in the optics cavity. (24 Vdc)

Removes heat from around the fusing unit and blower the ozone built up around the charge section to the ozone filter. (115/220/230/240 Vac)

Overall

Information

Magnetic Clutch

MC1 Toner Supply Clutch Drives the toner supply roller. 6

Magnetic Spring Clutches

MSC1 2nd Paper Feed

Clutch MSC2 Paper Lift Clutch Lifts paper to the appropriate feed station. 13 MSC3 Registration Clutch Drives the registration rollers. 15 MSC4 Relay Roller Clutch Drives the relay rollers for the 2nd or 3rd

MSC5 3rd Paper Feed

Clutch

Solenoids

SOL1 1st Paper Feed

Clutch Solenoid

SOL2 Pick-up Roller

Release Solenoid

SOL3 Development

Clutch Solenoid

Starts paper feed from the 2nd paper feed station.

paper feed station. Starts paper feed from the 3rd paper feed

station. (A111 copier only)

Starts paper feed from the first paper station. 14

a) After the paper is fed, releases the pick-up roller from next paper. b) When the manual feed table is used, releases the pick-up roller from the table.

Drives the development unit. 5

1-13

ELECTRICAL COMPONENT DESCRIPTIONS 1 May 1993

Symbol Name Function Index No.

Switches

SW1 Main Switch Supplies power to the copier. 42 SW2 Cover Safety Switch Cuts the ac power line when the front cover

or/and exit cover is open.

SW3 1st Paper Size

Switch

SW4 2nd Paper Size

Switch-1 (Upper)

SW5 2nd Paper Size

Switch-2 (Lower)

SW6 Color Switch Determines which color development unit is

SW7 Manual Feed Table

Switch

SW8 Right Cover Switch Detects when the right cover is open. 16 SW9 3rd Paper Size

Switch-1 (Upper) SW10 3rd Paper Size

Switch-2 (Lower)

SW11 Platen Cover

Closed Switch

Determines what size paper is in the cassette.

Determines what size paper is in the upper paper tray.

installed. Detects when the manual feed table is open. 11

Determines what size paper is in the lower tray. (A111 copier only)

Detects when the platen cover or the document feeder is closed.

(A111 copier only)

Sensors

S1 Scanner Home

Position Sensor

S2 Lens Home

Position Sensor

S3 4th/5th Mirror Home

Position Sensor

S4 Registration Sensor Detects misfeeds. 22 S5 Exit Sensor Detects misfeeds. 33 S6 1st Paper End

Sensor

S7 2nd Paper End

Sensor

S8 Color Toner End

Sensor

S9 Paper Lift Sensor Detects the correct feed height of the

S10 Image Density (ID)

Sensor

Informs the CPU when the 1st scanner is at the home position.

Informs the CPU when the lens is at the home position (full size position).

Informs the CPU when the 4th/5th mirrors assembly is at the home position (full size position).

Informs CPU when the cassette runs out of paper.

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

Detects when it is time to add toner for the color development unit.

cassette. Detects the density of the image on the

drum to control the toner density.

1-14

1 May 1993 ELECTRICAL COMPONENT DESCRIPTIONS

Symbol Name Function Index No.

S11 Auto Image Density

Sensor (ADS)

S12 3rd Paper End

Sensor

S13 Relay Sensor Detects misfeeds. (A111 copier only) 20 S14 Platen Cover

Position Sensor

S15 Original Width

Sensor

S16 Original Length

Sensor

S17 Toner Overflow

Sensor

Printed Circuit Boards

PCB1 Main Board Controls all copier functions both directly

PCB2 AC Drive Board Drives all ac motors, the exposure lamp,

PCB3 Main DC Power

Supply Board

PCB4 Operation Panel

Board

PCB5 Noise Filter Board Removes the electrical noise.

PCB6 Option DC Power

Supply Board

Senses the background density of the original.

Informs CPU when the lower paper tray runs out of paper. (A111 copier only)

Detects when the platen cover is positioned about 10 cm (4") above the exposure glass.

(A111 copier only) Detects the original width. (A111 copier

only)

Detects the original length.

(A111 copier only)

Detects when the used toner tank is full. 31

and through the other PCBs.

fusing lamp, quenching lamp, exhaust blower motor.

Rectifies 26 (31) Vac and 10 Vac input and outputs dc voltages.

Informs the CPU of the selected modes and displays the situations on the panel.

(220/230/240 V only) Rectifies 26 and 10 Vac input and outputs

dc voltages. This board is required when the document feeder or/and duplex unit is installed. (A110 copier only)

Overall

Information

Lamps

L1 Exposure Lamp Applies high intensity light to the original for

exposure. L2 Fusing Lamp Provides heat to the hot roller. 27 L3 Quenching Lamp Neutralizes any charge remaining on the

drum surface after cleaning.

L4 Erase Lamp Discharge the drum outside of the image

area. Provides leading/trailing edge, side and editing erases.

L5 Pre-transfer Lamp Reduces charge on the drum surface before

transfer.

1-15

ELECTRICAL COMPONENT DESCRIPTIONS 1 May 1993

Symbol Name Function Index No.

Power Packs

P1 CC/Grid/Bias

Power Pack

P2 TC/SC Power Pack Provides high voltage for the transfer and

Heaters

H1 Drum

Anti-condensation Heater

H2 Optics

Anti-condensation Heater (Option)

Counters

CO1 Total Counter Keeps track of the total number of copies

CO2 Key Counter

(Option)

Provides high voltage for the charge corona,

grid, and the development roller bias.

separation corona.

Prevents moisture around the drum. 44

Prevents moisture from forming on the

optics.

made.

Used for control of authorized use. Copier

will not operate until installed.

N/A

Transformer

TR1 Main Transformer Steps down the wall voltage to 26 (31) Vac

and 10 Vac.

TR2 Option Transformer Steps down the wall voltage to 26 Vac and

10 Vac. This transformer is required when

the document feeder or/and duplex unit is

installed. (A110 copier only)

Others

TH Fusing Thermistor Monitors the fusing temperature. 30

TF Fusing Thermofuse Provides back-up overheat protection in the

fusing unit.

TS Optics

Thermoswitch

C Main Motor

Capacitor

Provides back-up overheat protection

around the exposure lamp.

Start capacitor 57

1-16

1 May 1993 AC POWER AND DC POWER DISTRIBUTION

8. AC POWER AND DC POWER DISTRIBUTION

Noise Filter Board (220/230/240V only)

Exhaust Blower

Fusing Lamp

Exposure Lamp

Main Motor Quenching Lamp Exhaust Blower Motor (H)

Optional Transformer

26V AC 10V AC

FU100 (5V) FU101 (24V)

Optional DC Power Supply Board

24V

(VA)5V(VC)

ARDF

AC Power (115V or 220/230/240V)

FU401

Motor (L)

A110 copier

24V

(VA)5V(VC)

Duplex

Cover Safety SW

FU401 (115V only)

Power Relay (RA401)

Fusing Lamp Drive Circuit

Exposure Lamp

Drive Circuit

Main Motor Relay (RA402)

AC Drive Board

Scanner Motor Drive Circuit

30V (VM) A110 copier

24V (VM) A111 copier

Scanner Motor

A110 copier

Main SW

Control Signal

24V (VA)

Lens Motor

Main Transformer

24V (VA)

Zero Cross

30V (VM) 5V (VC)

24V (VM) 24V (VA)

10VAC 26VAC 26VAC

Control Signal

Zero Cross

RAM PCB

Main Board

Main DC Power Supply Board

Anti-condensation Heater

Scan Signal 5V (VC)

24V (VA)

24V (VA) 5V (VC)

A111 copier

24V (VA) For Sorter

24V (VA)

5V (VC)

FU100 (5V) FU101 (24V) FU102 (30V)

- Drum

- Optics (Option)

Operation Panel Board

Sensors/Switches

Solenoids Clutches

Power Packs 4th/5th Mirror Motor Optics Cooling Fan

Motors

Sorter

24V (VA)

5V (VC)

ARDF Duplex

Overall

Information

A B

ac power dc power

A111 copier

Main Transformer

1-17

10VAC

31VAC

Main DC Power

Supply Board

FU101 (5V, 24V)

24V (VA)

5V (VC)

24V (VA)

5V (VC)

24V (VA)

24V (VM)

Zero Cross

A B C D

E F G

For optional equipment

AC POWER AND DC POWER DISTRIBUTION 1 May 1993

When this copier is plugged in and the main switch is turned off , ac power is supplied via the ac drive board to the anti-condensation heate r. Whe n the front cover and/or the exit cove r is open, the cover safety switch complete ly cuts off power to all ac and dc components. The RAM board has a back up power supply (dc battery) for the service program mode and misfeed job recovery.

(A110 copier)

When the main switch is turned on, the ac power sup ply to the anti-condensation heat er is cut of f an d ac power is supp lied to the ac drive board. The main and optiona l tran sformers receive wall outlet ac power through the ac drive board. It outputs 10 volt s ac and 26 volt s ac t o the main and optional dc power supply boards.

The main dc power supply board converts the 10 volts ac to +5 volts and a zero cross signal. There are two 26 volts ac inpu ts. The main dc power supply board converts them to +24 volts an d +30 volts.

The +5 volt and +24 volt currents are supp lied to the cop ier main boa rd and ac drive board. The +30 volt current is supp lied to th e ac drive board. The zero cross signal is supplied to the copier main board thro ugh the ac drive board.

The copier main board supplie s dc powe r to all cop ier dc components except the scanner motor and lens motor. All sensors a nd switches operate on +5 volts. All other dc comp on ents including the power relay (RA401) and the main moto r relay (RA4 02 ) ope rat e on +24 volts. The copier main board also supplie s the +5 volt an d +24 volt curre nt s to the sorter.

The ac drive board supplies +3 0 volt s to the scanner motor and +24 volt s to the lens motor. The +5 volt current is dc power for the ICs on the scanner motor drive circuit. The main board sends the control signals to the scanner motor and len s motor through the ac drive board.

The optional dc power supply boa rd sup plie s +5 volts and +24 volts to the duplex unit and ARDF.

1-18

1 May 1993 AC POWER AND DC POWER DISTRIBUTION

(A111 copier) When the main switch is turned on, the ac power sup ply to the

anti-condensation heat er is cut of f an d ac power is supp lied to the ac drive board. The main transformer receives wall outlet ac power thro ugh the ac drive board and outputs 10 volts ac and 31 volts ac to the main dc power supply board.

The main dc power supply board converts the 10 volts ac input to +5 volts and a zero cross signal. The dc power supply board converts the 31 volts ac to +24 volts.

The +5 volt and +24 volt currents are supp lied to the cop ier main boa rd, ac drive board. The zero cross signal is supplied to th e cop ier main board through the ac drive boa rd.

The copier main board supplie s dc powe rs to all cop ier dc components except the scanner motor and lens motor. All sensors a nd switches operate on +5 volts. All other dc comp on ents including the power relay (RA401) and the main moto r relay (RA4 02 ) ope rat e on +24 volts. The copier main board also supplies th e +5 volt and +24 volt currents to the sorter, ARDF and duplex unit.

Overall

Information

The ac drive board supplies +2 4 volt s to the scanner motor and lens motor. The +5 volt current is dc power fo r the ICs on th e scan ne r motor drive circuit. The main board sends the cont rol signals to the scanner motor and lens motor through the ac drive board .

When the main board receives power, it act ivat es th e power rela y (RA401) which then supplies ac power to the fusin g lamp drive circuit, and the exposure lamp drive circuit on the ac drive board. The exhaust blower motor begins rotating at low speed. The fusing lamp drive circuit receives a trigger signal from the main board an d the fusing lamp lights. The exp osure lamp does not turn on until the main boa rd send a trigger pulse to the exp osu re lamp drive circuit.

When the Start key is pressed, the main bo ard ene rgize s the main mot or relay (RA402). Then, the main motor and the quenching lamp turn on an d th e exhaust blower starts rotating at high speed.

When the main switch is turned off, power is cut off to the main board an d to RA401, and the drum and optional anticondensatio n he aters are turned on. The exposure lamp and the fusing lamp power lines are complete ly disconnected from the lin e volt ag e.

1-19

SECTION 2

DETAILED SECTION

DESCRIPTIONS

1 May 1993 DRUM

1. DRUM

1.1 OPC DRUM CHARACTERISTICS

An OPC has the characteristics of:

1. Being able to accept a high negative electrical charge in the dark. (Th e electrical resistance of a photocon ductor is high in the absence of light.)

2. Dissipating the electrical charge when exposed to light. (Exposure to light greatly increases the conduct ivity of a photo con du cto r.)

3. Dissipating an amount of charge in dire ct pro po rtio n to the inte nsity of the light. That is, where stronger light is directed to the photoconductor surface, a smaller voltage remains on the OPC.

4. Being less sensitive to changes in tempe r at ure (wh en compared to selenium F type drums).

5. During the drum’s life, drum residu al volt ag e gra du ally increases and the photoconductive surface becomes worn. Therefore, some compensation for these characteristics is required .

Detailed

Descriptions

2-1

[G]

[D]

[F]

DRUM 1 May 1993

1.2 DRUM UNIT

[E]

[H]

[B]

[C]

[A]

[C]

An organic photoconducto r drum [A] is used on this model. A drum unit [B] is used to hold the drum to pre ven t stress on the drum. The

drum unit consists of an OPC drum, ID sensor [C] and pick-off pawls [D]. When the drum is replaced, and/or th e pick-o ff pawls an d/ or th e ID sensor are cleaned, the drum unit must be removed from the copier as a unit.

The drum is driven by the main mo to r [ E] through the main motor gear [F ], a relay gear and the drum drive gear [G]. The pick-off pawls are always in contact with the drum surfa ce. The ID sen sor is electrically connected to the ID sensor connector [H].

2-2

1 May 1993 DRUM CHARGE

2. DRUM CHARGE

2.1 OVERVIEW

[C]

[D]

[A]

[D] [B]

Detailed

Descriptions

[A]

This copier uses a single wire scorotro n and a hig hly sensitive OPC drum [A]. The corona wire [B] genera tes a corona of negative ions when the CC/Grid/Bias power pack [C] applies a high voltage. The CC/Grid/Bias power pack also applies a negative high volta ge to a stainless steel grid plate [D]. This insures that the drum coating receives a uniform negative charg e as it rotates pa st the corona unit.

The exhaust blower, locat ed abo ve the cop y exit, causes a flow of air from the upper area of the development unit through the charge corona unit. This prevents uneven build -up of negative ions that can cau se un even image density. The exhaust blower runs at half speed when in the stand-by condition and runs at fu ll sp ee d while copying.

The exhaust blower has an ozone filte r (a ctive carbo ns) which adsorbs ozone (O3) generated by th e coro na charge. The ozone filter decre ase s in eff icien cy over time as it adsorbs ozone. The ozone filter should be replaced at every 60,000 copies.

The flow of air around the charge corona wire may deposit paper dust or toner particles on the corona wire . The se pa rticle s may interfere with charging and cause low density ba nd s on cop ies. The wire clea ne r clean s the corona wire when the op erator slides the corona unit in and out.

2-3

[C]

DRUM CHARGE 1 May 1993

2.2 CHARGE CORONA WIRE CLEANER MECHANISM

[B]

[A]

[D]

Pads [A] above and below th e charge corona wire clean the wire as th e charge unit is manually slid in and out.

The cleaner pad bracket [B ] rotates when the charge unit is fully e xte nd ed and the bracket is pulled up against the rear block [C]. This moves the pads against the corona wire (see illustra tio n). If the charge unit is not fully extended, the pads do not tou ch th e corona wire.

The pads move away from the wire when the charg e unit is f ully inse rted and the cleaning bracket is pushed against the front block [D].

After copier installatio n the key operator should be instructe d ho w to use this mechanism when copies have whit e stre aks.

2-4

1 May 1993 DRUM CHARGE

2.3 CHARGE CORONA CIRCUIT

VA [24]

VC [5]

CC Trig [▼24]

Grid Trig (PWM) [▲0→0/5]

Not Used

GND [0]

CN112-8 CN112-7 CN112-6 CN112-5 CN112-4 CN112-3 CN112-2 CN112-1

CN1-1 CN1-2 CN1-3 CN1-4 CN1-5 CN1-6 CN1-7 CN1-8

CC/Grid/Bias

Power Pack

(P1)

Charge

Corona Wire

Grid

Development

Roller

Main Board (PCB 1)

The main board supplies +24 volt s to th e CC/G rid/Bias power pack at CN1-1 as the power supply source. After the Start key is pressed, the CPU drops CN1-3 from +24 volts to 0 volts. This energizes the charge coron a circuit within the CC/Grid/Bias power pack, which applies a high nega tive volta ge of approximately –5.6 kv to the cha rge corona wire. The corona wire then generates a negative corona charge.

Detailed

Descriptions

The grid limits the charge voltage to ensu re th at the charge does not fluctuate and an even charge is applied to the drum surf ace .

The grid trigger pulse applied to CN1-5 is a pulse width modulated signal (PWM signal). This signal is not only a trigger signal; it also chan ges the voltage level of the grid. As the width of the pulse ap plie d incre ases, the voltage of the grid also incre ases.

2-5

DRUM CHARGE 1 May 1993

2.4 GRID VOLTAGE CORRECTION

To maintain good copy quality ove r the drum’s life , th e grid volta ge is changed by the following:

• Drum residual voltage correctio n (Vr corre ctio n)

• Vp correction

2.4.1 Drum Residual Voltage Corre ction (Vr correction)

During the drum’s life, the dru m may fat igu e electrically and residual voltage (Vr) on the drum may gradually increase. When this happens, the corona charged voltage on th e dru m is not disch arged enough in the quenching an d exposure processes. Even if the development bia s is applie d in th e development process, the background area of th e orig inal on the drum may attract some toner. This may cause dirty background on copies. The Vr correction prevents this ph enomenon as follows:

A pattern (Vr pattern) is develope d on the drum eve ry 100 0 cop ies and its reflectivity is detected by the ID sen sor to measu re th e resid ua l volta ge . This is called residual voltage detect ion . If the reflectivity is low, the residual voltage will be high.) When the Vr pattern is developed, all blocks of the erase lamp turn on, the grid voltage is –500 volts and the development bias voltage is 0 volt.

The CPU determines what level of Vr co rrect ion is necessa ry dep en din g on the output (Vr ratio [L]) from the ID sensor.

Vrp

L =

x 100(%)

Vsg

Vrp: ID sensor output for Vr pattern

Vsg: ID sensor output for bare drum The current Vr ratio is disp laye d by SP67. The CPU increases the development bias voltage depending on the Vr ratio

to prevent dirty backgrou nd on copies. (See page 2-33 for more informatio n. ) The CPU also increases the grid volta ge to ensure prop er imag e de nsit y depending on the Vr ratio. (See page 2-8.)

2-6

1 May 1993 DRUM CHARGE

2.4.2 Vp Correction

Due to the OPC drum’s characteristics, the chargeability of the photoconductor may decrease until around 2,000 copies after installation. It will stay stable after 2,000 copies. This charact erist ic e spe cially affe cts developing of the ID sensor pattern. The ID senso r pat tern developed on the drum becomes lighter afte r 2,0 00 copie s causin g higher toner concentratio n in the developer. Vp correctio n is ma de to pre ven t this phenomenon and is as follows:

The CPU keeps track of the total numb er of copie s made with th e drum . The grid voltage for the toner densit y det ection increases by –20 volts after 2, 00 0 copies (see page 2-8). The drum counter is displayed by SP69 . The coun ter must be reset by SP66 when th e drum is replaced with a new one.

Detailed

Descriptions

2-7

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Ricoh FT4220.22 Service Manual FT4220

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