Ricoh 5733 Diagram

FT5733/5433

(contains FT4727/4427 Information)

SERVICE TRAINING

MANUAL

SECTION 1

OVERALL MACHINE

INFORMATION

1. SPECIFICATIONS

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

Minimum 51/2" x 81/2" By-Pass Tray Only

(Duplex Copying) Multiple: Single/Overlay:

81/2" x 11" (sideways) Maximum 11" x 17" Minimum 81/2" x 11"

Rev. 10/92

Copy Paper Weight: • 250-sheet paper tray and 1000-sheet large

capacity tray: 14 _34lb

• By-pass feed table:

14 _43lb

• Duplex and overlay:

17 _28lb

Reproduction Ratios: 4 Enlargement and 6 Reduction

FT5733/5433

200%

Enlargement

Full Size 100%

Reduction

155% 129% 121%

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

Receiving Tray Capacity:

250 sheets (81/2" x 14" and smaller) 100 sheets (11" x 17")

Power Source: 115V, 60HZ, more than 12A

STM 1-1 FT5733/5433

Rev. 10/92

Power Consumption: Maximum: 1.5 KW

Warm-up: 0.77 KW Stand-by: 0.14 KW Copy Cycle (average): 1.2 KW

Noise Emission: Stand-by: less than 40 dB

Copy Cycle (average):

less than 57 dB (copier only) less than 59 dB (full system)

Maximum:

less than 62 dB (copier only) less than 63 dB (full system)

Dimensions:

Width Depth Height FT5733 34.3" (42.2") 23.6" 21.3" (22.6") FT5433 34.3" (42.2") 23.6" 21.3" (22.6")

( ): When the by-pass feed table is opened, the copy tray is extended, and the platen cover is installed.

Weight: Copier only (Without the optional platen cover

= Approximately 2 kg) FT5733: approximately 194.0 lb

FT5433: approximately 185.2 lb Zoom: From 50% to 200% in 1% steps Copying Speed: 33 copies/minute (81/2" x 11" sideways)

18 copies/minute (11" x 17") Warm-up Time: Less than 2 minutes (20°C, 68°F) First Copy Time: Black copy:

4.9 seconds (81/2" x 11" sideways)

FT5733/5433: (Large capacity tray feed)

Color copy:

7.0 seconds

FT5733/5433: (Large capacity tray feed)

FT5733/5433 1-2 STM

Rev. 11/92

Copy Number Input: Ten keys, 1 to 999 (count up or count down) Manual Image Density: 7 steps Automatic Reset: 1 minute standard setting; can also be set to

3 minutes or no auto reset. Copy Paper Capacity: • By-pass feed table; approximately 20 sheets

• Paper tray: approximately 250 sheets

• Large capacity tray; approximately 1000 sheets

Toner Replenishment: Black: cartridge exchange

(320 g/cartridge) yield 10,500 copies

Color: cartridge exchange

(60 g/cartridge) yield 1300 copies

Developer

Black: (1000 g/bag) yield 80,000 copies Replenishment:

Color: (400 g/bag) yield 15,000 copies

Optional Equipment: • Platen cover

• DF56, Document feeder

• PS250, Paper tray unit with three paper tray

• CS2090, 20 bin mini sorter

• ST22, 20 bin sorter stapler

• TYPE G Sorter adapter (needed when installing

the mini, or the sorter stapler)

• TYPE G Interface PCB (needed when installing

the sorter stapler or the menu reader)

• MR20, Menu reader

• RE12, Editor (only for FT5733)

• TYPE B, Editing interface adapter (needed when

installing the editor)

• CU150, Color development unit

• Key counter

• DLT counter (service part)

STM 1-3 FT5733/5433

2. MACHINE CONFIGURATION

2.1 COPIER

FT5733(A074) FT5433(A073) UPPER TRAY DUPLEX 250 LOWER TRAY 250 250 LCT 1,000 1,000

Rev. 1/94

2.2 OPTIONAL EQUIPMENT

DF56

MR20 MENU READER (A952)

CS2090 20 BIN SORTER (A423)

ARDF (A497)

RE12 EDITOR

ST22 SORTER STAPLER (A366)

FT5733/5433 COPIER CABINET (438-MIU)

PS250 PAPER TRAY UNIT (A326)

FT5733/5433 1-4 STM

2.3 CONFIGURATION TABLE

COPIER REQUIRED OPTIONAL EQUIPMENT

FT5733 TYPE 2

(A074)

3 TRAY

PAPER

TRAY UNIT

DOCUMENT

FEEDER

EDITOR (A916) o x * * *

MENU READER (A952) o o * *

COLOR DEVELOPMENT

UNIT (A337)

(A326)

20 BIN MINI

(A423) 20 BIN

STAPLER

(A366)

ARDF

(A497)

FT5433

TYPE 3

(A073)

o o

o o *

o o * * *

o o

SORTER

ADAPTER

(A328)

INTERFACE

PCB

(A344)

Rev. 6/93

EDITING INTERFACE

ADAPTER (A345)

NOTE1: * The sorter adapter is required to install the 20 bin

mini sorter or sorter stapler.

* * The I/F board is required to install the sorter stapler

or Menu Reader.

* * * (1) The editing interface adapter is required to

install the editor.

(2) The editing interface adapter can be installed

independently when more precise erasing is desired.

NOTE 2: When installing the sorter stapler, the copier must be

placed on the paper tray unit or the system table or copier cabinet.

STM 1-5 FT5733/5433

3. COPY PROCESS AROUND THE DRUM

2. EXPOSURE

4. DEVELOPMENT

9. QUENCHING

8. CLEANING

1. DRUM CHARGE

3. ERASE

(COLOR)

4. DEVELOPMENT (BLACK)

ID/V SENSORS

PICK-OFF PAWLS

7. PAPER

5. PRE-TRANSFER LAMP

6. IMAGE TRANSFER

SEPARATION

FT5733/5433 1-6 STM

1. DRUM CHARGE

In the dark, the charge corona unit gives a uniform negative charge to the organic photo conductive (OPC) drum. The charge remains on the surface of the drum because the OPC layer has a high electrical resistance in the dark. The amount of negative charge on the drum is proportional to the negative grid bias voltage applied to the grid plate on the charge corona unit.

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.

The amount of remaining charge as a latent image on the drum depends on exposure lamp intensity controlled by the exposure lamp voltage.

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.)

The development bias voltage applied to the development roller shaft controls two things:

1) The threshold level if toner is attracted to the drum or toner remains on the development roller.

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

The higher the negative development bias voltage is, the less toner is attracted to the drum 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 from being reattracted to the drum surface during paper separation and makes paper separation easier.

STM 1-7 FT5733/5433

Rev. 10/92

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 reverse side of the copy paper, producing an electrical force which pulls the toner particles from the drum surface onto 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 reverse side of the copy paper, reducing the negative charge on the copy paper and breaking the electrical attraction between the paper and the drum. Along with the ac charge is a dc bias which will hold the toner in place and prevent toner scatter. Then, the stiffness and the weight of the copy paper causes it to separate from the drum surface. The pick-off pawls help to separate paper and drum.

8. CLEANING

The cleaning brush removes toner remaining on the drum after image transfer and the cleaning blade scrapes off all the remaining toner.

9. QUENCHING

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

FT5733/5433 1-8 STM

Rev. 1/94

4. MECHANICAL COMPONENT LAYOUT

424142

38 37

36 35

111098765

2 1

32 31

29 28 27

26 25 24 23

1. 3rd Mirror

2. 2nd Mirror

3. 1st Mirror

4. Exposure Lamp

5. Lens

6. Cleaning Brush

7. Quenching Lamp

8. Cleaning Blade

9. Change Corona Unit

10. OPC Drum

11. 6th Mirror

12. Erase Unit

13. 4th Mirror

14. 5th Mirror

15. Color Development Unit

16. Black Development Unit

17. Black Toner Supply Unit

18. Pre-Transfer Lamp

19. Feed Roller

22. Large Capacity Tray

23. Relay Rollers

24. Registration Rollers

25. Paper Tray Feed Roller

26. Friction Pad

27. Turn Gate

28. Duplex Friction Roller

29. Duplex Feed Roller

30. Transfer & Separation Corona Unit

31. Jogger Fences

32. End Fence

33. Lower Paper Tray

34. Entrance Rollers

35. Duplex Tray

36. Pressure Roller

37. Pick-off Pawls

38. Hot Roller

39. Junction Gate

20. Pick-up Roller

21. Separation Roller

40. Hot Roller Strippers

41. Transport Fan

42. Fusing Exhaust Fan

STM 1-9 FT5733/5433

5. DRIVE LAYOUT

1015

134

FT5733/5433 1-10 STM

1: Main Motor Pulley

3: Fusing Drive Belt

4: Drive Distribution

Gear/Pulley

23: Drive Distribution

Belt

12: Drive Distribution

Gear/Pulley

2: Drum Drive

25: Drum Drive

Drum

Cleaning drive

Cleaning Unit

20: Toner Supply Drive

Gear/Pulley

22: Toner Supply

CL Gear

21: Development

Unit Shift

10: Registration CL

26: Development

Drive Belt

24: Development

Drive CL Pulley

Development

9: Fusing Unit

Drive Gear

Fusing

6: Copier Exit

Roller Gear

7: Duplex Transport

Drive Belt

8: Duplex Transport

Roller Pulley

11: Upper Paper 13: Feed Relay CL

17: Relay Roller

19: Paper Feed Drive

Gear/Pulley

18: By-pass Feed

16: Paper Feed

Drive Belt

14: Lower paper

Feed CL Gear

5: Sorter Adapter Gears

CL Gear

15: Tray Unit drive

Gear

STM 1-11 FT5733/5433

6. PAPER PATH

6.1 NORMAL COPYING

[E]

[D]

[C]

[B]

[A]

Paper feed begins from the LCT or paper tray unit paper feed stations. The copy paper then follows one of two paths inside the copier. The path followed depends on which mode the operator has selected. For copy processing, all sheets follow the same path from the paper feed mechanism [A] through the registration [B], T & S corona [C], and fusing unit [D]. After that, normal copies are delivered to the copy tray [E], however, 2 sided copies and overlay copies are diverted for further processing.

FT5733/5433 1-12 STM

6.2 MULTIPLE 2-SIDED COPYING

[A]

[H]

[G]

[B]

[C]

[F]

[E]

[D]

Only paper that is 81/2" X 11" sideways can be used for multiple 2-sided copying. In this mode the junction gate [A] directs sheets exiting the fusing unit to the duplex tray entrance [B]. After that, all sheets follow the path through the entrance rollers [C], and the turn gate [D]. The turn gate directs paper through the duplex feed mechanism [E] to the duplex tray [F]. After all sheets are stacked in the duplex tray, they exit the duplex unit via the duplex feed mechanism and relay rollers [G] to the registration rollers [H]. After that, the sheets follow the same path as normal copying from the registration rollers to the copy tray.

STM 1-13 FT5733/5433

6.3 SINGLE 2-SIDED COPYING

[A]

[D]

[B]

[C]

All US (letter) sizes, excluding half letter, can be used for single 2 sided copying. In this mode, the sheet follows the same path as in multiple 2-sided copying to the duplex tray. However, the end fence [A] of the duplex tray lowers. The sheet advances over the lowered end fence. The sheet is stopped by the friction between the duplex feed and friction rollers [B,C]. It is then directed to the relay rollers [D] by the reversed duplex feed roller. After that, the sheet follows the same path as in multiple 2-sided copying from the relay rollers to copy the tray.

FT5733/5433 1-14 STM

6.4 SINGLE IMAGE OVERLAY COPYING

[B]

[A]

In this mode, the sheet follows the same path as in multiple 2-sided copying to the turn gate [A]. The turn gate directs the sheet to the relay rollers [B]. The sheet stays there to allow the second original to be placed and to exchange the black and color development units if the color overlay mode has been selected by the operator. After that, the sheet follows the same path as in multiple 2-sided copying from the relay rollers to the copy tray.

STM 1-15 FT5733/5433

7. ELECTRICAL COMPONENT DESCRIPTION

Refer to the electrical component layout on the reverse side of the Point to Point (Water proof paper) for symbols and index numbers.

Symbol Name Function Index No. Motors

M1 Main Drives the main unit

components.

M2 Exhaust

blower

M3 Upper tray lift

(non-duplex machine only)

M4 Lower tray lift Raises the bottom plate in the

M5 Transport fan Provides air flow to the

Blows the ozone built up around the charge section through the ozone filter.

Raises the bottom plate in the upper paper tray.

lower paper tray.

transport section so that paper is held on the transport guide. Also the air flow isolates the toner collection tank from fusing heat. Provides air flow to the charge corona section as well.

M6 Fusing

exhaust fan

M7 Scanner drive Drives the 1st and 2nd

M8 3rd scanner

drive

M9 Optics cooling

fan

M10 Lens drive Positions the lens. 100 M11 Duplex feed

(duplex machine only)

M12 Jogger

(duplex machine only)

M13 LCT lift Lifts up and lowers the LCT

Removes the heat from around the fusing unit.

scanners (dc stepper). Drives the 3rd scanner (dc

stepper). Removes heat from the optics

unit.

Drives the feed roller and moves the bottom plate up and down (24 V dc stepper).

Drives the jogger fences to square the paper stack in the duplex tray (dc stepper).

bottom plate.

103

107

FT5733/5433 1-16 STM

Symbol Name Function Index No. Circuit Board

PCB1 DC power

supply

Drives the exposure and fusing lamps and rectifies 100 Vac or 220/230/240 Vac input and outputs dc voltages.

PCB2 Main control Controls all copier functions

both directly and through the other control boards.

PCB3 Scanner motor

control

PCB4 Main motor

control

PCB5 Operation

panel

Controls the speed of the scanner drive motor.

Controls the rotation of the main motor.

Controls the LED matrix, and monitors the key matrix.

PCB6 ADS sensor Senses the background density

of the original.

PCB7 High voltage

supply - CTBG

Supplies high voltage for the charge corona, grid bias, transfer corona, and development bias.

PCB8 High voltage

supply - D

PCB9 PTL/QL

stabilizer

Supplies high voltage for the separation corona.

Provides high voltage for the quenching and pre-transfer lamps.

PCB10 Duplex control

(duplex

Controls the rotation of the duplex feed motor.

machine only)

PCB11 LCT interface Interfaces the LCT control

signal between the main control board and the LCT.

PCB12 Guidance

display control

Controls the guidance display

board. (duplex machine only)

PCB13 Guidance

display

Displays guidance for machine

operation. (duplex machine only)

106

PCB14 Interface -

type G (option for sorter

Interfaces the sorter stapler and

menu reader with the main

control board.

stapler and menu reader)

STM 1-17 FT5733/5433

Symbol Name Function Index No. Switches

SW1 Upper paper

size - 1 (non-duplex machine only)

SW2 Upper paper

size - 2 (non-duplex machine only)

SW3 Upper paper

size - 3 (non-duplex machine only)

SW4 Upper paper

size - 4 (non-duplex machine only)

SW5 Lower paper

size - 1

Determines what size paper is

in the upper paper tray.

Determines what size paper is

in the upper paper tray.

Determines what size paper is

in the upper paper tray.

Determines what size paper is

in the upper paper tray.

Determines what size paper is

in the lower paper tray.

SW6 Lower paper

size - 2

SW7 Lower paper

size - 3

SW8 Lower paper

size - 4

Determines what size paper is

in the lower paper tray.

Determines what size paper is

in the lower paper tray.

Determines what size paper is

in the lower paper tray.

SW9 Color detection Detects if color development

unit is set or not and which

color toner development unit is

installed.

SW10 Exit cover

Cuts the ac power line. 64 (Duplex machine only)

SW11 Platen cover Informs the CPU when the

platen cover is closed.

SW12 Front door

safety

Cuts the ac power line through

RA1 and detects if the front

door is open or not.

SW13 Main Supplies power to the copier. 95 SW14 LCT cover - 1 Detects if the LCT cover is

open or not.

SW15 LCT cover - 2 Cuts the dc power line of the

LCT lift motor.

FT5733/5433 1-18 STM

Symbol Name Function Index No.

W16 LCT down Sends a signal to the CPU to

lower the LCT bottom plate.

Lamps

L1 Quenching Neutralizes any negative

47 charge remaining on the drum surface after cleaning.

L2 Pre-transfer Reduces the charge on the

49 drum surface before transfer.

L3 Fusing Provides heat to the hot roller. 60 L4 Exposure Applies high intensity light to

99 the original exposure.

L5 Erase Eliminates the charge for

48 unnecessary areas of the image on the drum surface before exposure.

Magnetic Clutches

MC1 Development

Drives the development roller. 11

drive

MC2 Toner supply Drives the toner supply roller. 14 MC3 By-pass / LCT

feed

Starts paper feed from the by-pass feed table or LCT.

MC4 Feed relay Drives the relay rollers. 19 MC5 Registration Drives the registration rollers. 20 MC6 Upper paper

feed

Starts paper feed from the upper paper tray.

(non-duplex machine only)

MC7 Lower paper

feed

Starts paper feed from the lower paper tray.

STM 1-19 FT5733/5433

Symbol Name Function Index No. Solenoids

SOL1 Development

unit change

Changes the position of the black development unit and color development unit.

SOL2 Pick-up roller Picks paper up from the

by-pass feed table or LCT.

SOL3 Duplex tray

lock (duplex

Locks the duplex tray in the main copier.

machine only)

SOL4 Upper tray

lock

Locks the upper paper tray in the main copier.

(non-duplex machine only)

SOL5 Lower tray lock Locks the lower paper tray in

the main copier.

SOL6 Junction gate

(duplex machine only)

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

SOL7 Duplex turn

gate (duplex machine only)

Moves the duplex turn gate to direct copies to the duplex tray or to the relay rollers.

Sensors

S1 By-pass feed

table

S2 Upper tray set

(non-duplex

Detects if the by-pass feed table is open or closed.

Detects if the upper paper tray is set or not.

machine only)

S3 Lower tray set Detects if the lower paper tray

is set or not.

S4 By-pass feed

paper end

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

S5 Upper tray

paper end (non-duplex

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

machine only)

105

S6 Lower tray

paper end

Informs the CPU when the lower paper tray runs out of

25 paper.

S7 Upper tray

upper limit (non-duplex

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

machine only)

FT5733/5433 1-20 STM

Symbol Name Function Index No.

S8 Lower tray

upper limit

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

S9 Lower relay Detects the lead edge of paper

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

S10 Upper relay Detects the lead edge of paper

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

S11 Registration Detects the lead edge of paper

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

S12 Image density

(ID)

Detects the density of the ID sensor pattern on the drum to control the toner density.

S13 V Detects the VR and VL patterns. 58 S14 Fusing exit Detects misfeeds. 62 S15 Junction gate

Detects misfeeds. 63

(duplex machine only)

S16 Scanner H.P. Informs the CPU when the 1st

68 scanner is at the home position.

S17 Lens H.P. Informs the CPU when the lens

72 is at the full-size position.

S18 Platen position Informs the CPU when the

74 platen cover is positioned. When the angle between, the platen cover and the exposure glass is about 30 degrees.

S19 3rd scanner

H.P.

Informs the CPU when the 3rd scanner is in the full size

76 position.

S20 Original length Detects the original length. 89 S21 Original width Detects the original width. 96 S22 Duplex

Detects misfeed. 109

entrance (duplex machine only)

STM 1-21 FT5733/5433

Symbol Name Function Index No.

S23 Duplex turn

gate (duplex machine only)

S24 Duplex paper

end (duplex machine only)

S25 Jogger H.P.

(duplex machine only)

S26 LCT paper

end

S27 LCT lower

limit

S28 LCT upper

limit

Heaters

Detects the trail edge of paper

101

to determine the reverse timing of the duplex motor and detects misfeed.

Detects copy in the duplex tray. 102

Detects if the jogger fences are

108

at home position.

Informs the CPU when the LCT

runs out of paper. Sends signal to CPU to stop

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

lifting up the LCT bottom plate.

H1 Drum Turns on when the main switch

is off to prevent moisture around the drum.

H2 Optics

anti-condensatio n (option)

H3 Upper tray

(option)

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

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

H4 Lower tray

(option)

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

Thermistor

TH1 Drum Monitors the temperature

around the drum.

TH2 Fusing Monitors the temperature of the

hot roller.

TH3 Optics Monitors the temperature of the

optics cavity.

TH4 Duplex motor

(duplex

Monitors the temperature of the duplex motor.

104

machine only)

FT5733/5433 1-22 STM

Symbol Name Function Index No. Thermofuse

TF1 Fusing Provides back-up overheat

protection in the fusing unit.

Thermoswitch

TS1 Optics Provides overheat protection in

the optics unit.

Noise filter

NF1 Removes electrical noise. 40

Fuse

FU1 Main (115 V

machine only)

Provides back-up high current protection in the electrical

components. (125V 15 Amps)

FU2 Sorter line

(115 V machine only)

Provides back-up high current protection in the electrical components of the sorter.

FU3 DF line (115 V

machine only)

Provides back-up high correct protection in the electrical

components of the ARDF.

Circuit Breaker

CB1 (230 V

machine only)

Provides back-up high current protection in the electrical

components.

Relay

RA1 Main power Controls main power. 45

Transformer

TR1 Main Steps down the wall voltage to

100 V ac.

Counter

CO1 Total Keeps track of the total number

of copies made.

STM 1-23 FT5733/5433

SECTION 2

DETAILED SECTION

DESCRIPTION

1. PROCESS CONTROL

1.1 OVERVIEW

Exposure Lamp Voltage

Grid Bias Voltage

ID Sensor Pattern V Sensor Pattern

Toner Supply

(Color)

Drum Thermistor

(Black)

ID Sensor

V Sensor

Development

Bias

Voltage

As seen in section 1 the copy process around the drum and the copy image (image and background density) are controlled by many factors.

On this copier, the following items are controlled during the copy process to maintain good copy quality:

The exposure lamp voltage of the optics section The grid bias voltage of the drum charge section The development bias voltage and toner supply of the development section

The items above use the following electrical components:

The operation panel (manual ID selection and reproduction ratio),

ADS

sensor, ID sensor, V sensor, drum thermistor, paper size switches, color detection switches, and RAM board (drum rotation time and SP mode data)

Refer to the process control table in the back of the Field Service Manual for the details on which electrical component controls which item.

In the following sections, we will explain briefly how the major electrical components are controlled in the copy process.

STM 2-1 FT5733/5433

1.2 ID SENSOR CONTROL

Sensor

Original Lead Edge

Pattern

Original

OFF

A B C

RAM Clear

1 2 3 4 5 6 7 8 9 10 11 12 13 14 20 21 22

Toner Density Detection Toner Density Detection Toner Density

D E

OFF

Leading Edge Erase

1st

Detection

ID Sensor Pattern

2nd 3rd

Low Toner Density

Toner Supply Timing

Toner Add

Toner Supply Clutch ON

(10 times)

Development Bias

Detection

1.2.1 Overview

An ID (Image Density) sensor is used to control toner supply. The sensor is located on the drum unit, under the cleaning unit.

Placing the sensor under the cleaning unit, instead of the development unit, reduces the risk of scattered toner getting on the sensor.

The CPU checks toner density through the ID sensor by directly sensing the image density on the drum. This is done every 10 copy cycles (every 5 copy cycles for the color development unit). Turning the main switch off and on has no effect because the count is stored in RAM. If the drum initialization is performed (SP mode #66) or the RAM is cleared (SP mode #99), the CPU starts counting for the toner density check from the beginning of the first copy cycle.

The ID sensor pattern (black) is positioned on the operator side of the bottom of the left scale bracket. During the check cycle, the ID sensor pattern is exposed prior to exposure of the original.

After the ID sensor pattern is developed, the ID sensor checks the pattern’s reflectivity and the CPU notes it. If the reflected light is too strong, indicating toner density is too low, toner is added to the development unit.

FT5733/5433 2-2 STM

The toner is not added all at once. The CPU energizes the toner supply clutch for the proper amount of time to add a calculated amount of toner over the next 10 copy cycles (5 copy cycles for color toner).

Such toner supply control through the ID sensor is called a detect supply mode. On this copier, this mode is used to control both black and color toner supply.

STM 2-3 FT5733/5433

1.2.2 ID Sensor Output

VSG = 4.0 ± 0.2

1/10 VSG = 0.4

(V)

LED

VSG

LED

VSP

VSG

1/10 VSG

(T)

VSP

Low image density

High image density

Bare drum

Sensor pattern

When in the toner density check cycle, the CPU receives two voltage values directly from the ID sensor: Vsg and Vsp. Vsg is the voltage value for the area of the drum made bare by the erase lamp unit before the ID sensor pattern is exposed. Vsp is the voltage value for the developed ID sensor pattern. The CPU compares these two values to monitor the image density on the drum and with this controls the toner supply.

Vsg is the reference voltage of the ID sensor output and is automatically adjusted to 4V whenever SP mode #54 is called.

The development bias for the ID sensor pattern is fixed for each toner color. This is to avoid any influence from the manual ID level setting on toner density control. (See chart.)

[Standard

setting]

Black toner

Red/Blue toner

Green toner

0 to 500

copies

220 V

200 V

240 V

Over 500

copies

200 V

180 V

220 V

FT5733/5433 2-4 STM

+ 239 hidden pages