Ricoh DS5330 OVERALL MACHINE INFORMATION

SECTION 1

OVERALL MACHINE

INFORMATION

Overall

Information

1 February 1994 SPECIFICATIONS

1. SPECIFICATIONS

Copy Process: Laser electrostatic transfer system Originals: Book/sheet, fixed platen Original Alignment: Front-right corner Maximum Original Size: 11" x 17"/A3 Copy Paper Size: Maximum: 11" x 17"/A3

Minimum: 5

1/2" x 81/2"/A5

Copy Paper Weight: Bypass feed: 17 to 42 lb/64 to 157 g/m

Side cassette: 17 to 42 lb/64 to 157 g/m Front trays: 17 to 28 lb/64 to 104 g/m

Copying Speed: 30 copies per minute (81/2" x 11" sideways)

31 copies per minute (A4 sideways) 18 copies per minute (11" x 17") 18 copies per minute (A3)

First Copy: 5.8 seconds (8

1/2" x 11"/A4 sideways) from

side cassette

Warm-up Time: Within 5 minutes

(Room temperature 23°C/73°F)

Copy Counters:

Set counter: 1 to 999 (max. is adjustable by SP mode) Copy counter: 1 to 999 ( count-up or count-down, can be

selected by SP mode)

Paper Capacity: Cassette: 250 sheets

Manual feed table: 30 sheets

2 2 2

Copy Tray Capacity: 250 sheets (8

1/2" x 14"/B4 and smaller)

100 sheets (11" x 17"/A3)

Automatic Reset: After 60 seconds (3 min. can be selected by

SP mode)

-- Reproduction Ratio: Full size

-- Interrupt Mode: OFF

-- 2 Single Copies: OFF

-- Sort/Stack: OFF

* : It is possible to be changed by SP mode

-- Duplex: OFF

-- Set Counter: 1

-- Copy Counter: 0

1-1

SPECIFICATIONS 1 February 1994

-- Image Density: Auto ID *

-- User Program Mode: OFF

-- Total Area Editing: OFF

-- Letter/Photo mode: Letter mode

-- Designated Area Editing: OFF

-- Cassette: 1st or LCT *

-- Auto Reduce/Enlarge: OFF

-- Auto Paper Selection: ON * Photoconductor: Organic photoconductor drum Drum Charge: Dual-wire with grid plate (Negative Charge) Fixed Reproduction Ratios: 6 enlargement ratios and 7 reduction ratios

A4/A3 version LT/LDG version

800% 400%

Enlargement

Full Size 100% 100%

Reduction

200% 141% 122% 115%

93% 82% 75% 71% 65% 50% 25%

800% 400% 200% 155% 129% 121%

93% 85% 77% 74% 65% 50% 25%

Zoom: From 25% to 800% in 1% increments.

Allows independent horizontal and vertical percentage.

Scanning System: CCD, one directional scanning with mirrors

and lens Picture Element Density: 400 dots per inch (15.7 lines/mm) Scanner Light Source: Two fluorescent lamps (green light) Exposure System: Semiconductor laser, one dimensional

scanning Development:

• Dual-component dry toner system

• Double roller development

Toner Replenishment: 300 gram cartridge

1-2

Overall

Information

1 February 1994 SPECIFICATIONS

Toner Consumption: 5,500 copies/cartridge

1/2" x 11"/A4, 6% Originals)

(8 Development Bias: Negative fixed bias Toner Density Control: Pattern density detection by photosensor Image Transfer: Single wire dc (positive charge) Paper Separation: Dual wire ac corona and pick-off pawls Cleaning: Cleaning blade, cleaning brush, and

pre-cleaning corona Quenching: Photo quenching by LEDs Paper Feed System: Feed and reverse roller Image Fusing: Heat and pressure type, teflon (upper) and

silicone rubber (lower) rollers Fusing Lamp: Halogen lamp (115 V, 750 W/230 V, 800 W) Silicone Oil Consumption: More than 80,000 copies/500 cc

1/2" x 11"/A4 copies)

(8 Printer Feature Memory: Instruction ROM: 4 Mbytes

Font ROM: 2 Mbytes

Base RAM: 8 Mbytes PDL/Emulation: Adobe PostScript Level 2

HP LaserJet

compatible with HP LaserJet

ΙΙΙ (PCL-5) Emulation and

ΙΙΙsi, ΙΙD

Graphics:

Compressed files: Decompress raster graphic files (as per

Adobe PS 2 and HP PCL 5 specifications)

Conversion: Automatically convert 300 dpi bit-mapped

graphics for HP PCL 5 mode.

1-3

SPECIFICATIONS 1 February 1994

Fonts:

Adobe type 1: Outline fonts: Zapf Chancery, Zapf Dingbats,

Symbol plus four styles (normal, italic, bold,

bold-italic) each of Avant Garde Bookman,

Courier, Helvetica, Helvetica Narrow, New

Century Schoolbook, Times Palatino

HP/Intellifonts: Outline fonts: Zapf Dingbats plus four styles

(normal, italic, bold, bold-italic) each of

Univers, Univers Condensed, CG Times

Soft font capability: Outline fonts downloadable to memory or

optional hard disk Printer Port: RS232C serial

Bi-directional Centronics parallel

RS422 Appletalk Scanner Feature Scan Area: Max. 11" x 17"/A3 Scan Time: Max. 2 seconds (8

1/2" x 11"/A4 at full size

mode (400 dpi) Document Type: Book/Sheet Image Reduction: 25% (100 dpi) 50% (200 dpi) 75% (300 dpi) Output Data: Binary Digital Data

-- Black and White (fixed threshold)

-- Photo Mode (dither pattern) Brightness: From 1 to 7 Host Interface: SCSI-II Self-diagnostic Codes: 35 codes, indicated in the guidance display Power Source:

115 V/60 Hz/15 A, 220

∼ 240 V/50 Hz/8 A

Power Consumption: Maximum: 1.50 kW

Warm-up: 0.9 kW (average) Copy cycle: 1.1 kW (average) Stand-by: 0.15 kW

1-4

Overall

Information

1 February 1994 SPECIFICATIONS

Dimensions (W x D x H): Machine frame only: 27.6" x 28.8" x 23.8"

700 x 732 x 605 mm

Full system: 63.0" x 28.8" x 44.5"

1600 x 732 x 1130 mm

Weight: Approximately 216.1 lb/112 kg (Main frame

only) Approximately 413.6 lb/188 kg (Full system)

Optional Equipment: -- ARDF (automatic reverse document feeder)

-- 10 bin sorter

-- Auto duplex and LCT (1000 sheet) unit

-- LCT (1000 sheet) unit

-- Hard disk drive (40 MB)

-- Memory module unit (4 MB)

-- Scanner interface board

-- Key counter (locally procured)

1-5

DRUM PROCESSES 1 February 1994

2. DRUM PROCESSES

1. Charge

In the dark the charge corona unit applies a negative charge to the drum. The grid plate ensures that the charge is applied uniformly. The charge remains on the surface of the drum because the photoconductive drum has a high electrical resistance in the dark.

2. Laser Exposure

A laser beam exposes the drum, forming an electrical latent image on the drum surface.

3. Development

The magnetic developer brush on the development rollers comes in contact with the latent image on the drum surface. Toner particles are electrostatically attracted to the areas of the drum surface where the laser reduced the negative charge on the drum.

1-6

Overall

Information

1 February 1994 DRUM PROCESSES

4. Image Density Detection

On every 10th copy cycle, the laser forms a sensor pattern on the drum surface. The ID sensor measures the reflectivity of the pattern. When the image density of the pattern becomes too low, toner is supplied to the development unit.

5. Image Transfer

Copy paper is fed to the drum surface while a positive charge is applied to the back side of the paper. The positive charge pulls the toner particles from the drum surface onto the paper.

6. Paper Separation

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

7. Pre-cleaning Corona (PCC)

The PCC applies a strong ac corona discharge to the drum. This completely discharges the positive potential applied to the non-paper areas of the drum at the transfer section. The PCC has a negative bias which increases the negative charge on the toner remaining on the drum. This makes it easier for the cleaning brush to remove the toner from the drum surface.

8. Cleaning

The cleaning brush and cleaning blade remove any toner remaining on the drum surface. The cleaning brush is conductive and receives a positive charge from the bias roller (to which +150 Vdc is applied). This helps it to clean the negatively charged toner from the drum. The bias roller and a beater bar remove the toner from the cleaning brush.

9. Quenching

The light from the quenching lamp electrically neutralizes the surface of the drum.

1-7

COPY PROCESS 1 February 1994

3. COPY PROCESS

This section gives an overview of the copy process used in this machine. For more details, see the appropriate section description in the second chapter.

3.1 SCANNING AND IMAGE PROCESSING

3.1.1 Original Scanning

[A]

[B]

Main Scan Sub Scan

The scanner lamps [A] expose the original as in a normal copier. However, the optical system directs the light to the CCD [B] (charge coupled device) rather than a drum or OPC belt. The CCD converts the light intensity to electrical charges.

In this machine, the "main scan" direction refers to the direction perpendicular to scanner and paper travel. The "sub scan" direction is the direction of scanner movement, paper movement, and drum rotation.

1-8

Overall

Information

1 February 1994 COPY PROCESS

3.1.2 Photoelectric Conversion

The CCD contains 5,000 picture elements (pixels) in a line (400 dots/inch, 15.7 dots/mm). It converts the original light intensity into an electrical signal (analog).

Voltage

CCD Output

Main Scan

White

3.1.3 Analog to Digital Conversion

The analog signal output from the CCD is digitized. Eight bits are used for each pixel (picture element) which gives 256 gradation steps (256 level grayscale).

3.1.4 Image Processing

The digitized signal is then processed to convert the 8-bit grayscale image to 4-bit data which the laser unit can print (16 level grayscale). The image is processed in one or more of the following ways:

• Main scan magnification (sub

scan magnification is changed by varying the scanner speed)

8-Bit Data

4-Bit Data

Black

Analog

0 5000

27 26 25 24 23 22 21

2 1

0 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95

CCD Element

A/D Conversion

8 bits/256 graduation (Digital)

(F)

Black

Voltage

0.84

0.81

0.78

0.75

0.72

0.69

0.63

5000

: CCD Output : 8-Bit Digital

• Letter mode (line image) or

photo mode processing

(8)

• Identification of designated areas

• Double copy image processing

White

(0)

GrayWhite Black

1-9

COPY PROCESS 1 February 1994

3.2 DRUM EXPOSURE

A semiconductor laser exposes the drum. The laser is switched on and off at a very high frequency according to the image signal. Where the laser beam strikes the drum, the negative charge (about --850 volts) on the drum drops (to about --100 volts), forming an electrical latent image on the drum surface.

3’

2’

1’

Pitch 1/400" (63.5

The laser beam is reflected by a turning polygon mirror. The light passes through a complex lens (called the f

Θ lens) to the drum.

Main scanning (or in this case writing) is from front to rear, and one surface of the polygon mirror is used for each line.

µ)

Polygon Mirror

Pitch 1/400" (63.5µ)

1 2 3 4 5 6 7

Mainscan

fΘ Lens

Laser Drive

4’ 3’ 2’ 1’

Subscan

Drum

1-10

OFFONOFF

--850 V

Mainscan

Overall

Information

1 February 1994 COPY PROCESS

3.3 DEVELOPMENT PROCESS

[A]

[B]

A: OPC Drum B: Development Roller

Most copiers use either a positively charged photoconductor and negatively charged toner or a negatively charged photoconductor and positively charged toner. This is known of as positive/negative development. However, this machine uses a negative/negative process where both the drum surface charge and the toner charge are negative. The negative/negative process has certain advantages for laser printing, but some copy problems are exactly opposite from what many copier service people have intuitively come to expect. The table on the following page gives some of the differences between the positive/negative process and the negative/negative process.

1-11

COPY PROCESS 1 February 1994

Positive/Negative Development VS. Negative/Negative Development (2- component dry development process)

Positive/Negative Negative/Negative

Type of Laser He-neon (gas,

630 nm) Photoconductor Se Drum OPC OPC Charge Corona Positive Negative Negative Carrier Charge Positive Negative Positive Toner Charge Negative Positive Negative Photoconductor

Exposure

Background exposure (write to

white)

He-neon or semiconductor

Semiconductor (780 nm)

Image exposure (write to black)

P: Pitch (1/400" in this model) D: Laser beam diameter

D: Drum voltage

B: Bias voltage

R: Residual

voltage L1, L2: Line width (L1 < L2 for the same laser beam diameter)

Copy Problems

1. No photoconductor charge

2. Low photoconductor charge

3. High development bias

4. Low development bias

5. Stained toner shield glass

V 0V

White copy Black solid copy

Low image density Dirty background

Dirty background Low image density

Black stripes White stripes

1-12

Overall

Information

1 February 1994 MECHANICAL COMPONENT LAYOUT

4. MECHANICAL COMPONENT LAYOUT

38 37

36 35

1 2 3 4 5 6 7 8 9

11 12

14 15

16 17 18 19

33 32 31 30 29 28 27 26 25 24 23 22 21 20

1. Polygon Mirror Motor

2. F

θ Lens

3. Sensor Board Unit (SBU)

4. Lens

5. Quenching Lamp

6. Charge Corona Unit

7. Drum Mirror

8. Development Rollers

9. Exposure Lamps

10. First Mirror

11. Second Mirror

12. Third Mirror

13. Side Paper Feed Roller

14. Side Pick-up Roller

15. Multi By-pass Tray

16. First Relay Roller

17. First Paper Feed Roller

18. Second Relay Roller

19. Second Paper Feed Roller

20. Second Pick-up Roller

21. First Pick-up Roller

22. Registration Rollers

23. Image Density Sensor

24. Transfer/Separation Corona Unit

25. Pre-Cleaning Corona Unit

26. Cleaning Unit

27. Transport Belt

28. Vacuum Fan

29. First Cassette

30. Pressure Roller

31. Second Cassette

32. Hot Roller

33. Fusing Exit Roller

34. Return Pinch Roller

35. Return Gate

36. Inverter Entrance Gate

37. Lower Exit Rollers

38. Junction Gate

39. Upper Exit Rollers

40. Printer Control Board

1-13

DRIVE LAYOUT 1 February 1994

5. DRIVE LAYOUT

30 29

1 2 3

4 5

6 7 8

16 17

1. Side Paper Feed Clutch

2. Toner Supply Clutch

3. Development Clutch

4. Registration Clutch

5. Drum Drive Gear

6. Drum Drive Belt

7. Cleaning Drive Gear

8. Main Motor Gear

9. Main Drive Chain

10. Fusing Drive Gear

11. Hot Roller Drive Gear

12. Inverter Unit Drive Gear

13. Upper Exit Roller Gear

14. Exit Roller Drive Belt

15. Lower Exit Roller Gear

16. Reverse Pinch Roller Drive Belt

24 23

17. Reverse Pinch Roller Gear

18. Used Toner Tank Drive Gear

19. First Paper Lift Motor

20. Second Paper Lift Motor

21. Second Paper Lift Gear

22. First Paper Lift Gear

23. Second Paper Lift Gear

24. Second Separation Roller Gear

25. First Paper Feed Clutch

26. Second Relay Roller gear

27. First Separation Roller Gear

28. First Relay Roller Gear

29. Relay Clutch

30. Side Separation Roller Gear

31. Side Paper Lift Gear

32. Side Paper Lift Motor

19 18

1-14

Overall

Information

1 February 1994 ELECTRICAL COMPONENT DESCRIPTIONS

6. 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. M2 Scanner Motor Drives the scanner. 21 M3 Side Paper Lift

Motor

M4 1st Paper Lift

Motor

M5 2nd Paper Lift

Motor

M6 Polygon Mirror

Motor

M7 Optics Cooling

Fan Motor

M8 Exhaust Fan

Motor

M9 Printer Controller

Fan Motor

M10 Printer Controller

Cooling Fan Motor

M11 Charge Fan

Motor

M12 Vacuum Fan

Motor

M13 LD Cooling Fan

Motor

Lifts the side cassette’s bottom plate. 15

Lifts the 1st cassette’s bottom plate. 9

Lifts the 2nd cassette’s bottom plate. 8

Turns the polygon mirror. 4

Cools the optics cavity. 3

Removes the air around the transport and the

fusing unit.

Removes the air around the printer I/F board. 2

Cools the printer I/F board area. 19

Provides a flow of air to the charge corona unit

to prevent uneven charge.

Provides suction so that paper is held firmly on

the transport belt.

Cools the LD driver board area. 6

Magnetic Clutches

MC1 Registration

Clutch

MC2 Side Paper Feed

Clutch

MC3 Relay Roller

Clutch

MC4 1st Paper Feed

Clutch

MC5 2nd Paper Feed

Clutch

MC6 Development

Clutch

Solenoids

SOL1 Toner Supply

Solenoid

Turns the registration rollers. 10

Starts paper feed from the side feed station. 14

Turns the relay rollers. 13

Starts paper feed from the first feed station. 12

Starts paper feed from the second feed station. 11

Transmits the main motor drive to the

development drive gears.

Turns on to supply toner to the development

unit.

1-15

ELECTRICAL COMPONENT DESCRIPTIONS 1 February 1994

SYMBOL NAME FUNCTION INDEX NO.

SOL2 Cleaning

Solenoid

SOL3 Side Pick-up

Solenoid

SOL4 1st Tray Lock

Solenoid

SOL5 2nd Tray Lock

Solenoid

SOL6 2nd Pick-up

Solenoid

SOL7 1st Pick-up

Solenoid

SOL8 Return Pinch

Roller Solenoid

SOL9 Junction Gate

Solenoid

SOL10 Inverter

Entrance Solenoid

Presses the cleaning blade against the drum. 98

Controls the up-down movement of the side

pick-up roller.

Locks the first tray during coping cycle. 96

Locks the second tray during coping cycle. 95

Controls the up-down movement of the second

pick-up roller.

Controls the up-down movement of the first

pick-up roller.

Opens the return gate and presses the return

pinch roller against the return roller.

Opens the junction gate. 23

Opens the inverter entrance gate. 24

Switches

SW1 Main Switch Provides the power to the copier. 35 SW2 Front Door

Safety Switches

SW3 Anti-

condensation

Switch SW4 Function Switch Provides the power to the printer I/F board. 36 SW5 Right Upper

Door Switch SW6 Left Upper Door

Switch

Sensors

S1 Scanner H.P.

Sensor

S2 Scanner Unit Lift

Sensor

S3 Original Length

Sensor

S4 Original Width

Sensor 1

S5 Original Width

Sensor 2

S6 Platen Cover

Position Sensor

S7 Manual Feed

Width Sensor

Cuts dc power and the +5 volts for the laser operation when the front cover is opened.

Cuts the power to the tray and lamp heaters, drum heater, and the anti-condensation heater when the switch turns off.

Detects when the right upper door is opened. 54

Detects when the left upper door is opened. 25

Notifies the CPU when the scanner is at the home position.

Notifies the CPU when the scanner unit is closed.

Detects the original length. 29

Detects the original width. 66

Detects the original width. 67

Gives the signal to perform original size detection with open platen cover condition.

Informs the CPU of the width of paper which is in the multi by-pass tray.

1-16

Overall

Information

1 February 1994 ELECTRICAL COMPONENT DESCRIPTIONS

SYMBOL NAME FUNCTION INDEX NO.

S8 Side Paper Lift

Sensor

S9 Side Paper Size

Sensor

S10 1st Upper Limit

Sensor

S11 2nd Upper Limit

Sensor

S12 Manual Feed

Sensor

S13 Oil End Sensor Detects when it is time to add silicone oil. 37 S14 1st Paper Set

Sensor

S15 2nd Paper Set

Sensor

S16 1st Lower Limit

Sensor

S17 2nd Lower Limit

Sensor

S18 1st Relay Sensor Detects misfeeds. 49 S19 2nd Relay

Sensor

S20 Side Relay

Sensor

S21 2nd Paper End

Sensor

S22 1st Paper End

Sensor

S23 2nd Paper Size

Sensor

S24 1st Paper Size

Sensor

S25 Registration

Sensor

S26 ID Sensor Detects the density of the image on the drum. 40 S27 Fusing Exit

Sensor

S28 Platen Cover

Sensor

S29 Side Paper End

Sensor

S30 Toner Overflow

Sensor

S31 Upper Exit

Sensor

Detects the correct feed height of the side cassette.

Informs the CPU what size paper is in the side cassette.

Detects the correct feed height of the first cassette.

Detects the correct feed height of the second cassette.

Detects whether or not the manual feed table is in the down position.

Detects whether or not the first paper tray is in the main frame.

Detects whether or not the second paper tray is in the main frame.

Detects the bottom plate of the first cassette is in the down position.

Detects the bottom plate of the second cassette is in the down position.

Detects misfeeds. 48

Detects misfeeds. 47

Informs the CPU when the second cassette runs out of paper.

Informs the CPU when the first cassette runs out of paper.

Informs the CPU what size paper is in the second cassette.

Informs the CPU what size paper is in the first cassette.

Detects misfeeds. 41

Detects misfeeds. 34

Detects when the platen cover or the DF is closed, and gives the signal to perform original size detection with closed platen cover condition.

Informs the CPU when the side cassette runs out of paper.

Detects when the used toner tank is full. 39

Detects misfeeds. 28

1-17

ELECTRICAL COMPONENT DESCRIPTIONS 1 February 1994

SYMBOL NAME FUNCTION INDEX NO.

S32 Lower Exit

Sensor

S33 Inverter

Entrance Sensor

PCBs

PCB1 Main PCB Controls all copier functions both directly and

PCB2 AC Drive PCB Provides ac power to the fusing lamp. 76 PCB3 DC Drive PCB Drives the dc components such as the

PCB4 Operation Panel

PCB Unit

PCB5 Sensor Board

Unit (SBU) PCB

PCB6 Video

Processing Unit

(VPU) PCB

PCB7 Main Motor

Control PCB

PCB8 Image

Processing Unit

(IPU) PCB

PCB9 Laser Diode

(LD) Drive PCB

PCB10 Pulse Width

Modulation

(PWM) Control

PCB

PCB11 Printer Power

Supply PCB

PCB12 Printer Control

PCB

PCB13 Printer I/F Board

PCB

PCB14 Polygon Mirror

Motor Drive PCB

PCB15 Scanner I/F

Board PCB

(Option)

PCB16 DC Power

Supply PCB

PCB17 Inverter Drive

Board PCB

Detects misfeeds. 30

Detects misfeeds. 26

through other PCBs.

solenoids and sensors. The user controls the machine through this

PCB. Digitizes the original image as it is scanned. 75

Processes video read in through the SBU. 70

Controls the main motor. 20

Processes image read in through the VPU. 69

Controls the laser diode. 71

Provides the pulse to the other PCBs and components.

Provides the power for the printer I/F board. 68

Controls the printer functions. 81

Connects the interface harnesses for the printer.

Controls the polygon mirror motor. 5

Connects the interface harnesses for the scanner.

Provides dc power to the copier. 102

Controls the inverter unit. 27

Lamps

L1 Exposure Lamp Provides light to reflect the original’s image

onto the SBU.

1-18

104

Overall

Information

1 February 1994 ELECTRICAL COMPONENT DESCRIPTIONS

SYMBOL NAME FUNCTION INDEX NO.

L2 Quenching Lamp Neutralizes any charge remaining on the drum

surface after cleaning.

L3 Fusing Lamp Provides heat to the hot roller. 86

Power Packs

PP1 Transfer/

Separation

Power Pack

PP2 C/G/B/BR Power

Pack

Heaters

H1 Anticondensation

Heater

H2 Tray Heater Prevents moisture from forming inside the

H3 Lamp Heater Warms the exposure lamp. 103 H4 Drum Heater Keeps the drum warm to prevent condensation

Provides high voltage power for the transfer corona, pre-cleaning corona and the separation corona.

Provides high voltage power for the charge corona wire, development bias, grid bias and cleaning bias.

Prevents moisture from condensing on the optics.

copier.

on the drum.

100

101

Counters

CO1 Total Counter Counts the number of pages in copy and print

mode. CO2 Print Counter Counts the number of pages in print mode. 84 CO3 Key Counter

(Option)

Others

TH Thermistor Senses the temperature of the hot roller. 87

TF Thermofuse Opens the fusing lamp circuit if the fusing unit

NF Noise Filter Removes electrical noise from the AC input

CB Circuit Breaker Guards against voltage surges in the AC input

LS Lamp Stabilizer Powers the exposure lamps. 82

SMD Scanner Motor

Driver

HDD Hard Disk Unit

(Option)

Used for control of authorized use. Copier will

not operate until activated.

overheats.

line.

Controls the scanner motor. 22

Stores the fonts for printer. 61

1-19

SECTION 2

DETAILED SECTION

DESCRIPTIONS

1 February 1994 DRUM

1. DRUM

1.1 DRUM CHARACTERISTICS

The organic photoconductor (OPC) drum has the following characteristics:

• It is able to accept a high negative electrical charge in the dark. (The

electrical resistance of the OPC drum is high in the absence of light.)

• The electric charge on the drum surface dissipates when the drum is

exposed to light. (The conductivity of the OPC drum is greatly enhanced by exposure to light.)

• The OPC drum used in this machine is specially made for use with diode

lasers. It responds well to the 780 nm wavelength light of the laser used in this machine.

Detailed

Descriptions

2-1

DRUM 1 February 1994

1.2 DRUM DRIVE

[B]

[A]

[C]

The main motor turns the drum drive shaft [A] through the timing belt [B]. A drive pin [C] on the end of the drum drive shaft fits into slots in the end of the drum. This pin turns the drum whenever the main motor is on.

2-2

1 February 1994 CHARGE

2. CHARGE

2.1 OVERVIEW

[A]

[P1]

Detailed

Descriptions

[C]

[D]

[B]

C/G/B/BR P.P.

[C]

[D]

[B]

This model uses a dual wire corona unit [A] to charge the OPC (organic photoconductor) drum [B]. The corona wire [C] generates a corona of negative ions when a high negative voltage is applied to it by the charge/grid/ bias/bias roller power pack. To make the negative corona uniform, a thin stainless steel grid [D] is installed on the charge corona unit. The drum receives a charge of approximately --850 volts.

2-3

CHARGE 1 February 1994

2.2 CHARGE VENTILATION

[A]

[B]

[C]

Ozone from the charge corona unit can oxidize the surface of the drum. This oxidization can cause dirty background. To prevent this, the charge fan [A] circulates air through the charge corona unit [B]. The airflow from this fan is also directed to the auto image density sensor [C]. This helps to prevent toner from settling on the auto ID sensor.

The charge fan turns on and off at the same time as the main motor.

2-4

1 February 1994 CHARGE

2.3 CORONA WIRE CLEANER

[A]

[B]

Detailed

Descriptions

Toner particles or paper dust may be deposited on the corona wire by the air flow around the charge corona unit. Such particles may interfere with charging and cause dark lines on copies. The wire cleaner [A] allows the operator to correct this problem by pulling out and pushing in the charge corona unit.

When the corona unit is seated, the cleaning pads are held away from the corona wire as shown in the illustration. However, when the charge corona unit is pulled out, the wire casing [B] pushes the cleaning pads against the wire as shown in illustration.

2-5

CHARGE 1 February 1994

2.4 CHARGE CORONA CIRCUIT

Main Board

C-Trigger

G-Trigger

G-PWM

GND-Vcc

Grid voltage

(kV)

-0.5

-0.6

-0.7

-0.8

-0.9

-1.0

CN156

CN511

-A6

-A7

-A2

-A1 CN510

+24V (V )

GND

20 40 60 80 100 (%)

PWM Duty

-4

-3

-8

-9

-1

-3

G-PWM

C/G/B/BR Power Pack

Charge

Grid

L 0

Charge

PWM Duty =

t1 = 1 ms t2 = 0 ∼ 1 ms

Grid

x 100 (%)

The dc power supply board provides +24 volts (VAA) to the C/G/B/BR power pack. The CPU drops CN156-A6 and -A7 from +5 volts to 0 volt. These are the trigger signals for the high voltage power to the charge corona wire (approx. --6.5 kV) and the grid wire (approx. --0.87 kV). The actual charge applied to the OPC drum is approximately --850 volts.

Instead of a variable resister, the PWM control is used for the grid voltage. The output level of the grid voltage increases as the duty of the G-PWM signal increases as shown above.

The grid bias can be set by the SP2-1-1 (Grid Bias Adjustment).

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1 February 1994 SCANNING

3. SCANNING

3.1 OVERVIEW

[E]

[A]

[G]

[C]

Detailed

Descriptions

[F]

During scanning an image of the original is reflected on the CCD (charge coupled device) of the SBU (sensor board unit) via the optics assembly as follows:

Scanner Lamp [A] ⇒ Original ⇒ First Mirror [B] ⇒ Second Mirror [C]

⇒ Third Mirror [D] ⇒ Lens [E] ⇒ CCD (on SBU) [F]

Light from a band across the entire width (main scanning direction) of the document is focused on the CCD by the lens (1 : 0.1102 ratio). The CCD has 5,000 picture elements which convert the light intensity into electric charges. The image reading plate on the VPU converts the CCD charges into a 8-bit (256 gradations) digital signal. 2835 lines are digitized per second.

The scanning resolution is 400 dpi (15.7 dots/mm) in the main scanning direction. In full size mode it is also 400 dpi in the sub scanning direction. (The scanner speed is 180 mm/s when in full size mode.)

[B]

[H]

[D]

The white plate [G] is scanned prior to scanning the original. This gives a consistent white value which is used as a reference value to correct for variations in the fluorescent lamp or irregularities in the light striking the CCD.

The anti-condensation heater [H] keeps moisture from forming inside the scanner unit.

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SCANNING 1 February 1994

3.2 SCANNER LAMP

[B]

[A]

[C]

[D]

[E]

(without lamp grid) (with lamp grid)

The scanner lamps [A] are green fluorescent lamps with apertures so that most of the light is output in a single direction. They are controlled by the IPU board [B]. The scanner lamp stabilizer [C] drives the lamps with 15 W, 50 kHz power. The high frequency is necessary to achieve an even supply of light to the CCD, because the time for charging the CCD is 0.5 msec.

The scanner lamp heaters [D] keep the scanner lamp’s temperature at 40°C. This is necessary because the light intensity will be insufficient if the scanner lamp’s temperature is too low.

To prevent the light from being diffused, the lamp grid [E] is installed above the lamps. This grid can minimize the flare as shown the above illustration.

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1 February 1994 SCANNING

3.3 SCANNER LAMP CIRCUIT

Lamp Heater

Thermistor

Lamp Heater

Scanner Lamp

CN657-4

-3

-2

-1

-10

-9

-8

-7

CN656-3

-2

-1

Lamp Stabilizer

CN305-14

-13

-12

-11

CN305-7

-6

-5

[5] Vcc [0--5] Thermistor

[▼24] Lamp Heater [24] VAA

[0] G.VAA(INV) [24] VAA

[▼24] FLON

IPU Board

Detailed

Descriptions

The scanner lamp stabilizer is powered by +24 volts from CN305-6. To turn on the scanner lamp, the IPU board drops CN305-5 to Low. The scanner lamp stabilizer then provides high frequency power to the filaments of the scanner lamp.

The IPU board monitors the temperature of the scanner lamps through the lamp thermistor, and turns the scanner lamp heaters on and off to keep the scanner lamps at 40°C. It generally takes about 1 minute for the scanner lamps to reach 40°C after the main switch is turned on.

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