SHARP SFT 4015 User Manual

 IMPORTANT SAFETY NOTICES

PREVENTION OF PHYSICAL INJURY

1. Before disassembling or assembling parts of the copier and peripherals, make sure that the copier power cord is unplugged.

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

3. Note that the optional tray heater and the optional anti-condensation heaters are supplied with electrical voltage even if the main switch is turned off.

4. If any adjustment or operation 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 driven components.

5. The inside and the metal parts of the fusing unit become extremely hot while the copier is operating. Be careful to avoid touching those components with your bare hands.

HEALTH SAFETY CONDITIONS

1. Toner and developer are non-toxic, but if you get either of them in your eyes by accident, it may cause temporary eye discomfort. Try to remove with eye drops or flush with water as first aid. If unsuccessful, get medical attention.

OBSERVANCE OF ELECTRICAL SAFETY STANDARDS

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

SAFETY AND ECOLOGICAL NOTES FOR DISPOSAL

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

2. Dispose of used toner, developer, and organic photoconductors in accordance with local regulations. (These are non-toxic supplies.)

3. Dispose of replaced parts in accordance with local regulations.

SECTION 1

OVERALL

MACHINE INFORMATION

20 December 1996 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:

1/2

A5/5

1/2

A6/5

Non-standard sizes:

Vertical 45 mm ~ 308 mm, 1.8" ~ 12" Horizontal 148 mm ~ 432 mm, 5.8" ~ 17"

Copy Paper Weight: Paper tray feed: 64 to 90 g/m

By-pass feed: 52 to 157 g/m

" x 8 " x 8

1/2

" sideways (Paper tray feed)

1/2

" lengthwise (By-pass feed)

, 17 to 24 lb

, 14 to 42 lb

Overall

Information

Reproduction Ratios:

Enlargement

Full Size 100% 100%

Reduction

Metric Version Inch Version

200% 141% 122%

93% 82% 71% 50%

200% 155% 129%

93% 74% 65% 50%

Zoom: From 50% to 200% in 1% steps Copying Speed: 15 copies/minute (A4/8.5" x 11" sideways)

9 copies/minute (A3/11" x 17")

Warm-up Time:

120 V machines: Less than 30 seconds (at 23°C)

230 V machines: Less than 45 seconds (at 23°C) First Copy Time: Less than 6.9 seconds (A4/8.5" x 11" sideways) Copy Number Input: Number keys, 1 to 99 Manual Image Density

7 steps Selection:

Automatic Reset: 1 minute standard setting; can also be set to 3

minutes or no auto reset

1-1

SPECIFICATIONS 20 December 1996

Paper Capacity: Paper tray: 500 sheets or less than 56 mm stack

height

By-pass feed entrance:

Standard paper 80 sheets OHP 10 sheets Others 1 sheet

Toner Replenishment: Bottle exchange (215 g/bottle) Copy Tray Capacity: 100 sheets Power Source: 120 V/60 Hz: More than 15 A (for North America)

220 ~ 240 V/50 Hz: More than 8 A (for Europe)

220 V/50 Hz: More than 8 A (for Asia)

220 V/60 Hz: More than 8 A (for Middle East/Asia)

110 V/60 Hz: More than 15 A (for Taiwan)

127 V/60 Hz: More than 15 A (for Middle East) Power Consumption:

Dimensions:

Copier only Full system*

Maximum 1.4 kW

(120 V machines)

0.9 kW

(230 V machines) Copy cycle 0.71 kW 0.74 kW Warm-up 0. 95 kW 0. 95 kW Stand-by 0.25 kW 0.25 kW Energy saver 0.2 kW 0.2 kW

*Full system : Copier with document feeder and 10 - bi n sorter

Width Depth Height

Copier 579 mm

(22.8")

Full system* 775 mm

(30.2")

*Full system : Copier with document feeder and 10 - bi n sorter

560 mm

(22.1")

560 mm

(22.1")

1.5 kW

(120 V machines)

1.0 kW

(230 V machines)

420 mm

(16.6")

508 mm

(19.8")

1-2

20 December 1996 SPECIFICATIONS

Noise Emissions: Sound pressure level (the measurements are

made in accordance with ISO 7779 at the operator position.)

Copying Less than 57 dB Less than 61 dB

*Full system : Co pi er w i th d ocument feeder an d 10- bi n sorter

Copier only Full system*

Sound power level (the measurements are made in accordance with ISO 7779)

Overall

Information

Weight:

Optional Equipment: (Sales items)

Optional Equipment: (Servi ce items)

Copier only Full system*

Stand-by Less than 40 dB Less than 40 dB

Copy cycle Less than 63 dB Less than 67 dB

*Full system : Co pi er w i th d ocument feeder an d 10- bi n sorter

Copier only

Full system *

*Full system : Co pi er w i th d ocument feeder an d 10- bi n sorter

42 kg (93.0 lb)

55 kg (121 lb)

Document feeder (A662) 10-bin sorter (A657)

Optics anti-condensation heater Tray heater

•

Specifications are subject to change without notice.

1-3

COPY PROCESS AROUND THE DRUM 20 December 1996

2. COPY PROCESS AROUND THE DRUM

1-4

A219V503.wmf

20 December 1996 COPY PROCESS AROUND THE DRUM

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 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 area 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 attached 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.)

Overall

Information

5. 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.

6. PAPER SEPARATION

A strong positive dc charge is applied to the back side of the copy paper via a discharge plate, 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 the paper to separate from the drum surface.

7. CLEANING

The cleaning blade scrapes the toner off the drum. The collected toner is recycled.

8. QUENCHING

Light from the quenching lamp electrically neutralizes the drum surface.

1-5

MECHANICAL COMPONENT LAYOUT 20 December 1996

3. MECHANICAL COMPONENT LAYOUT

26 25

98654321

11 12

1. 2nd Mirror

2. 1st Mirror

3. Exposure Lamp

4. Hot Roller

5. Lens

6. Quenching Lamp

7. Charge Corona Unit

8. 6th Mirror

9. Erase Lamp

10. 4th Mirror

11. 5th Mirror

12. Toner Bottle Holder

13. By-pass Feed Roller

21 20

A219V500.wmf

14. By-pass Feed Table

15. Relay Rollers

16. Tray Paper Feed Rollers

17. Registration Rollers

18. Development Roller

19. Transfer/Separation Unit

20. Drum

21. Cleaning Blade

22. Pressure Roller

23. Paper Tray

24. Copy Tray

25. Exit Rollers

26. 3rd Mirror

1-6

20 December 1996 DRIVE LAYOUT

4. DRIVE LAYOUT

Overall

Information

543

1. Lens Motor

2. Fusing Unit Drive Gear

3. Main Motor

4. Drum Drive Gear

5. Tray Paper Feed Clutch Gear

6. Relay Roller Clutch Gear

A219V501.wmf

7. By-pass Paper Feed Clutch

8. Registration Clutch Gear

9. Toner Supply Motor

10. 4th/5th Mirror Motor

11. Scanner Drive Motor

1-7

PAPER PATH 20 December 199 6

5. PAPER PATH

1. By-pass Feed

2. Paper Tray Feed

3. Copy Tray

A219V502.wmf

1-8

20 December 1996 ELECTRICAL COMPONENT DESCRIPTIONS

6. ELECTRICAL COMPONENT DESCRIPTIONS

Refer to the electrical component layout and the point-to-point diagram on the waterproof paper in the pocket for symbols and index numbers.

Symbol Name Function Index No.

Motors

M1 M2 Scanner Drive M ot or Drives the sca nners (1st and 2nd). 9 M3

Main Motor Drives all th e m ai n unit component s except

for the optics u ni t and f ans.

Lens Motor Moves the lens position in accor dance with

the selecte d m agnification.

4th/5th Mirror Motor Moves the 4th/5th mirror position in

accordanc e w ith the selected magnification.

Toner Supply M ot or Rotates the to ner bot tle to supply toner to the

development uni t .

Optics Cooling Fan Motor

Exhaust Fan Mot or Removes heat fro m a ro und the fusing uni t

Prevents buil d- up of hot air in the opti cs cavity.

and blows the ozone built up aro und the charge corona unit towards the ozone filter.

Overall

Information

Clutches

CL1

CL2 CL3 Relay Roller Clutch Drives the relay rollers for paper tray feed. 13

CL4 Registration Clutch Drives the registration rollers. 11

Switches

SW1 Main Switch Supplies power to the copier. 38 SW2

SW3

SW4

Sensors

Tray Paper Feed Clutch

By-pass Paper F eed Clutch

Interlock Switch Cuts all power when the front cover is

Tray Paper Size Switch

Right Vertical Guide Switch

4th/5th Mirro r Hom e Position Sensor

ADS Sensor Detects the bac kground density of th e

Transfers ma in motor drive to the paper feed roller.

Starts paper fee d fr om t he by-pass feed table.

opened. Determines what size of paper is in the

paper tray. Cuts the +24 V dc power line of the relay

roller clutch.

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

original.

1-9

ELECTRICAL COMPONENT DESCRIPTIONS 20 December 1996

Symbol Name Function Index No.

Tray Paper End Sensor

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

Registratio n Sensor Detects the leading edge of th e copy paper

to determin e th e stop timing of the re l ay

roller clutc h , and detects misfeed s.

By-pass Feed Paper End Sensor

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

29 S6 Exi t Sensor D etects misfeeds. 23 S7

Scanner Home Position Sensor

Lens Home Posit ion Sensor

Toner Density (TD) Sensor

Informs the CPU w hen the 1st scanner i s at the home position.

Informs the CPU when the lens is at the home posit ion.

Detec ts the ra tio of ton er to car rier in th e developer.

Printed Circuit Boards

PCB1 Main Control Board Controls all copier funct i ons. 1

PCB2

High Voltage Supply Board - C/G/B/T/S

Provides high voltage to the charge corona, grid, development bias, transfer corona, and

discharge plate.

PCB3

AC Drive/DC Power Supply Board

Drives the exp o sure lamp, fusing l amp, and main motor. Rectifies 30 Vac and 8 Vac input

and outputs 5 Vdc and 24 Vdc.

PCB4

Operation Pane l Board

Informs the CPU of the selected mode s and displays the si t uation on the panel.

Lamps

Erase Lamp Discharges t he drum outside of th e i m age

area. (Provides leading/trailing edge and side erases.)

Quenching Lamp Neutralizes any charge remain i ng on the

drum surfa ce af t er cl eaning.

Exposure Lamp Applies high intensity light to the original for

exposure.

L4 Fusing Lamp Provides heat to the hot roller. 25

Others

CO1

TF1

Total Counter Keeps track of the t ot a l number of copies

made.

Tray Heater (Opt i on) Turns on when t he main switch is of f to keep

paper in the pa per tray dry.

Optics Anti-condensat i on Heater (Opti on)

Exposure Lamp Thermofuse

Turns on when t he main switch is of f to prevent moisture from accumulating in the optics.

Provide back-up overheat protection around the exposure lamp.

1-10

20 December 1996 ELECTRICAL COMPONENT DESCRIPTIONS

Symbol Name Function Index No.

TF2

TH1

TH2

Fusing Therm of u se Provide back-up overheat pro te ct i on i n t he

fusing unit.

Fusing Therm i st or Monitor s th e te mperature around t he

exposure lam p for overheat prot ect i on.

Optics Therm i st or Monitors th e te mperature around t he

exposure lam p for overheat prot ect i on.

Transformer Steps down the wall vol t age to 30 Vac and 8

Vac.

Overall

Information

1-11

SECTION 2

DETAILED DESCRIPTIONS

20 December 1996 DRUM

1. DRUM

1.1 OPC DRUM CHARACTERISTICS

The OPC (Organic Photoconductor) drum used in this copier is small in diameter (30 mm), ensuring good paper separation. An OPC drum has the following characteristics.

1. The drum is able to accept a high negative electrical charge in the dark. (The electrical resistance of a photoconductor is high in the absence of light.)

2. It dissipates the electrical charge when exposed to light. (Exposure to light greatly increases the conductivity of a photoconductor.)

3. The amount of charge dissipated is in direct proportion to the intensity of the light. That is, where stronger light is directed to the photoconductor surface, a smaller voltage remains on the drum.

4. An OPC drum is less sensitive to changes in temperature (when compared to selenium F type drums).

Detailed

Descriptions

5. During the drum’s life, drum residual voltage gradually increases and the photoconductive surface becomes worn. Therefore, some compensation for these characteristics is required.

2-1

DRUM 20 December 1996

1.2 DRIVE MECHANISM

[C]

[E]

[D]

[B]

[A]

A219D520.wmf

The drive from the main motor [A] is transmitted to the drum [B] through a series of gears, a timing belt [C], and the drum drive shaft [D].

When the imaging unit is installed in the copier, the drum drive shaft engages inside the drum’s flange [E] as shown.

2-2

20 December 1996 CHARGE

2. CHARGE

2.1 OVERVIEW

[A]

[B]

A219D505.wmf

[C]

Detailed

Descriptions

[D]

A219D521.wmf

This copier uses a single wire scorotron to charge the drum. The corona wire [A] generates a corona of negative ions when the high voltage supply unit applies a negative voltage. The stainless steel grid plate [B] ensures that the drum coating receives a uniform negative charge as it rotates past the corona unit.

The exhaust fan [C] causes a flow of air above and through the charge corona section. This prevents an uneven build-up of negative ions that can cause uneven image density.

An ozone filter [D], which absorbs ozone (O

) generated by the charge corona, is located beside the exhaust fan. The ozone filter decreases in efficiency over time as it absorbs ozone. The ozone filter should be replaced every PM cycle (45 k copies).

2-3

CHARGE 20 December 1996

2.2 CHARGE CORONA WIRE CLEANER MECHANISM

[C]

[D]

[A]

[B]

A219D536.wmf

Pads [A] move along the charge corona wire as the wire cleaner knob [B] is manually slid in and out.

The cleaner pad bracket [C] is connected to the wire cleaner knob. When the knob is pulled out, the pads move into contact with the corona wire as shown, since the casing [D] is narrower away from the home position.

The pads move away from the wire when the wire cleaner knob is fully inserted and the pad bracket is pushed back to the home position.

After copier installation, the key operator should be instructed to use this mechanism when copies have white streaks or uneven image density. Instruct the operator to firmly push the pad bracket into the home position. Poor copy quality will result if the cleaning pads remain in contact with the charge corona wire.

2-4

20 December 1996 CHARGE

2.3 CHARGE CORONA CIRCUIT

Main Board High Voltage Supply Board

24 V

GND

C Trigger

CN102-7 CN102-6 CN102-5

DC/DC

Converter

T Trigger

B-PWM

S Trigger

4.7 k

5 V

CN102-4

CN102-3

CN102-2

CN102-1

DC/DC

Converter

DC/DC

Converter

Zener Diode

DC/DC

Converter

Protection

Circuit

Drum

A219D506.wmf

Detailed

Descriptions

The main board supplies +24 V to the high voltage supply board at CN102-7. After the



key is pressed, the CPU drops CN102-5 from +24 V to 0 V. This activates the charge corona circuit which applies a high negative voltage of approximately –5 k volts to the charge corona wire. The corona wire then generates a negative corona charge.

The grid plate limits the charge voltage to ensure that the charge does not fluctuate and that an even charge is applied to the entire drum surface. The grid plate is connected to ground through a zener diode in the high voltage supply unit. The grid plate drains any charge in excess of –910 V, which is discharged to ground through the zener diode.

2-5

OPTICS 20 December 1996

3. OPTICS

3.1 OVERVIEW

[C][C] [A][B] [K] [E] [I] [G]

[D]

[F]

[H]

[J]

A219D507.wmf

During the copy cycle, an image of the original is reflected onto the drum surface through the optics assembly as follows:

Light path: Exposure Lamp [A] → Original → First Mirror [B] → Second Mirror [C] → Third Mirror [D] → Lens [E] → Blue Filter [F] → Fourth Mirror [G] → Fifth Mirror [H] → Sixth Mirror [I] → Drum [J]

This copier has eight standard reproduction ratios and a zoom function. The operator can also change the reproduction ratio in one-percent steps from 50% to 200%. Stepper motors are used to change the positions of the lens and 4th/5th mirrors to enlarge/reduce the image across the page. Changes in reproduction ratio down the page are achieved by changing the scanner speed.

The CPU monitors the temperature around the optics through a thermistor which is located on the scanner frame. When the temperature reaches 40°C, the optics cooling fan [K] starts rotating to draw cool air into the optics cavity. The fan operates until the temperature drops below 38°C.

Additionally, a thermofuse on the 1st scanner provides back-up overheat protection. It opens when the temperature reaches 128°C and cuts ac power to the exposure lamp.

A blue filter is located just after the lens to improve the reproduction of red areas of the original on copies.

2-6

20 December 1996 OPTICS

3.2 SCANNER DRIVE

[H]

[F]

[D]

[C]

[A]

Detailed

Descriptions

[E]

[B]

A219D522.wmf

[G]

A stepper motor [A] is used to drive the scanners. The first scanner [B], which consists of the exposure lamp and the first mirror,

is connected to the first scanner belt [C]. The second scanner [D], which consists of the second and third mirrors, is connected to the second scanner belt [E]. Both the scanners move along the guide rod [F].

There are no scanner drive wires, and only one side of the scanner is supported (by a rod and guide rail). Therefore, the scanners should be moved by moving the timing belt, and never by moving the scanners directly.

The pulley [G] drives both the first and second scanner belts. The 2nd scanner moves at half the speed of the first scanner. This maintains the focal distance between the original and the lens during scanning.

The scanner home position is detected by a home position sensor [H]. The scanner return position is determined by counting the scanner motor drive pulses.

2-7

OPTICS 20 December 1996

3.3 LENS DRIVE

[A]

[C]

A219D509.wmf

[B]

: Reduction : Enlargement

The lens motor [A] (stepper motor) changes the lens [B] position through the timing belt [C] in accordance with the selected reproduction ratio to provide the proper optical distance between the lens and the drum surface.

[D]

The rotation of the lens drive pulley moves the lens back and forth in discrete steps. The home position of the lens is detected by a home position sensor [D]. The main board keeps track of the lens position based on the number of pulses sent to the lens motor.

2-8

20 December 1996 OPTICS

3.4 4TH/5TH MIRROR DRIVE

[D]

[A]

[C]

[B]

A219D510.wmf

The 4th/5th mirror drive motor [A] (stepper motor) changes the 4th/5th mirror assembly position through the pinion gears [B] and the rack gear [C] in accordance with the selected reproduction ratio to provide the proper optical distance between the lens and drum surface.

Detailed

Descriptions

The home position of the 4th/5th mirror assembly is detected by a home position sensor [D]. The main board keeps track of the lens position based on the number of pulses sent to the 4th/5th mirror motor.

2-9

OPTICS 20 December 1996

3.5 AUTOMATIC IMAGE DENSITY SENSOR

[A]

A219D511.wmf

A219D512.wmf

The auto ID sensor [A], a photodiode, is mounted on the upper front frame. The sensor cover has a hole in it to allow light to fall directly onto the sensor.

Sampling starts 6 millimeters from the leading edge of the original and continues for 11.5 millimeters from the leading edge of original in full size mode. These lengths "a" and "b" will vary depending on the selected reproduction ratio. The lengths "a" and "b" for each reproduction ratio are calculated as follows:

Every original in ADS mode, the photosensor circuit converts the light intensity to a voltage. The detected voltage is amplified and sent to the main board. If less light is reflected from the original (the image is darker), the sensor outputs a lower voltage. The CPU compares the maximum ADS output voltage with the standard ADS reference voltage and compensates the copy image density by changing the development bias voltage in

accordance with the difference. The standard ADS reference voltage (2.5 ±

0.1 V) is generated by SP 56. Details about changes to the development bias voltage are explained in "Development Bias for Image Density Control".

2-10

20 December 1996 OPTICS

3.6 EXPOSURE LAMP VOLTAGE CONTROL

The main board controls the exposure lamp voltage through the ac drive/dc power supply board. The exposure lamp voltage is based on the base lamp voltage and various correction factors. The method of control is different depending on whether the image density is manually selected or the auto image density mode is selected.

The exposure lamp voltage is determined by the following factors:

Lamp Voltage = Base Lamp Voltage Setting (SP48)

*Image Density Adjustment Factor (SP34)

*Manual Image Density Setting Factor

Correction 1 Factor (SP62)

Correction 2 Factor

Reproduction Ratio Correction Factor

*NOTE:

SP34 (Image Density Adjustment Factor) is applied for ADS mode only. The "Manual Image Density Factor" is applied for manual ID mode only.

1) Base Lamp Voltage Setting The lamp voltage is determined by the SP48 setting.

Detailed

Descriptions

Base Lamp Voltage = SP48 setting x 0.5 (120 V machines)

SP48 setting x 1.0 (230 V machines)

The default setting is: 140 = 70 V (120 V machines)

140 = 140 V (230 V machines)

The current lamp voltage (after all correction factors are included) can be viewed with SP 51.

2-11

OPTICS 20 December 1996

2) Image Density Adjustment Factor (SP34) Depending on the SP34 setting, the development bias and the exposure

lamp settings are increased or decreased during ADS mode.

SP34 Setting Setting Dev. Bias Exposure Lamp

0Normal0 0 1 Light –40 V 0 2 Dark +40 V 0 3 Lightest –40 V +4 steps 4 Darkest +40 V –4 steps

1 step = 0.5 V (120 V machines) or 1.0 V (230 V machines)

3) Manual Image Density Setting Factor Depending on the manual image density setting on the operation panel, the

exposure lamp voltage is changed as shown in the table below:

LighterDarker

Manual ID

Level

Exposure Lamp Voltage Factor

Development Bias Voltage (Volts)

1234567

– 6

steps

–200 –200 –200 –200 –200 –240 –240

V0 – 4

steps

V0 – 2

steps

V0 + 2

steps

: Base lamp voltage setting (SP48)

1 step = 0.5 V (120 V machines) or 1.0 V (230 V machines)

V0 + 6

steps

V0 + 12

steps

2-12

20 December 1996 OPTICS

4) VL Correction 1 Factor The light intensity may decrease because of dust accumulated on the optics

parts. Additionally, the drum sensitivity gradually decreases during the drum’s life. This may cause dirty background on copies. To compensate for this, V

corrections 1 and 2 are done. The exposure lamp voltage is increased by two steps at the set copy count

interval (a step is +2.0 V for 230 V machines, and +1 V for 120 V machines). The table below shows the relationship between the SP setting and the interval.

SP62 Setting VL Correction Interval

0 2 steps/8,000 copies 1 2 steps/6,000 copies 2 2 steps/4,000 copies 3 2 steps/2,000 copies 4 2 steps/1,000 copies 5 No correc t i on

(Default setting: 2)

Detailed

Descriptions

VL correction 1 compensates for the decrease of drum sensitivity and the decrease in reflectivity of the 4th, 5th, and 6th mirrors due to dust.

5) V

Correction 2 Factor

correction 2 compensates for dust on the lens and mirrors 1 to 3, but is

independent of the drum condition. The ADS sensor receives the light reflected through the 1st, 2nd and 3rd

mirrors from the white plate located under the middle part of the left scale. The photosensor circuit converts this light intensity to a voltage, and the CPU stores this in memory as the white plate reference voltage. This is done every time SP56 (ADS reference voltage adjustment) is done, before sampling starts for the ADS sensor adjustment.

Every 500 copies, the machine reads the intensity of light reflected from the white plate and compares it with the white plate reference voltage.

If the measured voltage difference is more than 0.1 volt, +2 steps will be

added to the exposure lamp setting as the V The sum of V

correction factors 1 and 2 cannot exceed +40 steps.

correction 2 factor.

correction factors 1 and 2 are automatically reset every time the light

intensity is adjusted with SP48. (SP56 must be done immediately after SP48; see Service Remarks for details.)

2-13

OPTICS 20 December 1996

6) Reproduction Ratio Correction Factor The exposure lamp voltage is increased depending on the selected

magnification ratio in order to compensate for the change in concentration of light on the drum.

Magnification Ratio Reproduction Ratio Correction Factor

50% to 61% +2 steps 62% to 119% 0 120% to 139% +2 steps 140% to 159% +4 steps 160% to 179% +8 steps 180% to 200% +12 steps

1 step = 0.5 V (120 V machines) or 1.0 V (230 V machines)

2-14

20 December 1996 ERASE

4. ERASE

4.1 OVERVIEW

A219D513.wmf

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[A]

Detailed

Descriptions

A219D527.wmf

The erase lamp [A], which is installed in the copier main frame, consists of a single row of white LEDs (38 LEDs) extended across the full width of the drum. The erase lamp has the following functions: leading edge erase, side erase and trail edge erase. (Trail edge erase begins after the trailing edge of the copy paper; therefore, the trailing edge of the copy will not be erased.) In side erase mode, the appropriate LEDs turn on in accordance with the modes selected by the user.

2-15

ERASE 20 December 1996

4.2 LEAD EDGE ERASE

The entire line of LEDs turn on when the main motor turns on. They stay on until the erase margin slightly overlaps the lead edge of the original image area on the drum (Lead Edge Erase Margin). This prevents the shadow of the original edge from being developed on the copy. At this point, side erase starts. The width of the leading erase margin can be adjusted using SP41.

4.3 SID E ERASE

Based on the combination of copy paper size and the reproduction ratio data, the LEDs turn on in blocks (labeled "a" to "n" on the previous page). This reduces drum cleaning load.

Also, to prevent horizontal black lines from appearing on the edge of copies as a result of light leaking under the edge of the DF belt, the side erase combination is changed between platen mode and DF mode; in DF mode, more of the image is erased at the sides. (The setting of SP24 must be 0.)

-Platen Mode-

Blocks On Paper Size

None 99% to 200%

a to b 95% to 98%

a to c a to d 88% to 91% a to e

a to f 80% to 83%

a to g 75% to 79% a to h

a to i a to j 63% to 67%

a to k B5 59% to 62%

a to l 54% to 58%

a to m 50% to 53%

All (a to n)

11" x 17",

11" x 8

B4, B5

sideways

1/2

" x 11",

1/2

" x 5

Lengthwise

Lead Edge and Trai l Edge Erase

Reproduction

1/2

Ratio (%)

92% to 94%

84% to 87%

72% to 74%

68% to 71%

-DF Mode-

Blocks On Paper Size

None 99% to 200%

a to b 97% to 98% a to c a to d 90% to 92% a to e

a to f 81% to 85%

a to g 77% to 80% a to h

a to i a to j 65% to 69%

a to k B5 61% to 64%

a to l 56% to 60%

a to m 50% to 55%

All (a to n)

11" x 17",

11" x 8

B4, B5

sideways

1/2

" x 11",

1/2

" x 5

Lengthwise

Lead Edge and Trai l Edge Erase

Reproduction

1/2

Ratio (%)

93% to 96%

86% to 89%

73% to 76%

70% to 72%

2-16

+ 233 hidden pages