Ricoh FT 3813, FT 4018 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:
	A5/51/2" x 81/2" sideways (Paper tray feed)
	A6/51/2" x 81/2" lengthwise (By-pass feed)
	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/m2, 17 to 24 lb
	By-pass feed: 52 to 157 g/m2, 14 to 42 lb

Information

Overall

Reproduction Ratios:
		Metric Version	Inch Version
		200%	200%
	Enlargement	141%	155%
		122%	129%
	Full Size	100%	100%
		93%	93%
	Reduction	82%	74%
		71%	65%
		50%	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:

Copier only

Full system*

Maximum

1.4 kW

1.5 kW

(120 V machines)

(120 V machines)

0.9 kW

1.0 kW

(230 V machines)

(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-bin sorter

Dimensions:

Width

Depth

Height

Copier

579 mm

560 mm

420 mm

(22.8")

(22.1")

(16.6")

Full system*

775 mm

560 mm

508 mm

(30.2")

(22.1")

(19.8")

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

1-2

20 December 1996

Noise Emissions:

Weight:

Optional Equipment: (Sales items)

Optional Equipment: (Service items)

SPECIFICATIONS

Sound pressure level (the measurements are				Overall Information
	Copier only	Full system*
made in accordance with ISO 7779 at the
operator position.)
Copying	Less than 57 dB	Less than 61 dB

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

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

	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: Copier with document feeder and 10-bin sorter

Copier only	42 kg (93.0 lb)
Full system*	55 kg (121 lb)

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

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

2

8

1

3

7

4

6

5

A219V503.wmf

1-4

20 December 1996 COPY PROCESS AROUND THE DRUM

1. DRUM CHARGE	Overall Information
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.)
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

1	2	3	4		5	6	7	8	9	10
										11
										12
										13
26
25
										14
24										15
										16
23
			22	21	20		19	18	17
										A219V500.wmf

1.	2nd Mirror	14.	By-pass Feed Table
2.	1st Mirror	15.	Relay Rollers
3.	Exposure Lamp	16.	Tray Paper Feed Rollers
4.	Hot Roller	17.	Registration Rollers
5.	Lens	18.	Development Roller
6.	Quenching Lamp	19.	Transfer/Separation Unit
7.	Charge Corona Unit	20.	Drum
8.	6th Mirror	21.	Cleaning Blade
9.	Erase Lamp	22.	Pressure Roller
10.	4th Mirror	23.	Paper Tray
11.	5th Mirror	24.	Copy Tray
12.	Toner Bottle Holder	25.	Exit Rollers
13.	By-pass Feed Roller	26.	3rd Mirror

1-6

20 December 1996

4. DRIVE LAYOUT

11

DRIVE LAYOUT

Information

Overall

10
9	1
8	2
7
6

	5	4	3		A219V501.wmf
1.	Lens Motor			7.	By-pass Paper Feed Clutch
2.	Fusing Unit Drive Gear			8.	Registration Clutch Gear
3.	Main Motor			9.	Toner Supply Motor
4.	Drum Drive Gear			10.	4th/5th Mirror Motor
5.	Tray Paper Feed Clutch Gear			11.	Scanner Drive Motor
6.	Relay Roller Clutch Gear

1-7

PAPER PATH

20 December 1996

5. PAPER PATH

3

1

2

A219V502.wmf

1.By-pass Feed

2.Paper Tray Feed

3.Copy Tray

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	Main Motor	Drives all the main unit components except	8
			for the optics unit and fans.
	M2	Scanner Drive Motor	Drives the scanners (1st and 2nd).	9
	M3	Lens Motor	Moves the lens position in accordance with	18
			the selected magnification.
	M4	4th/5th Mirror Motor	Moves the 4th/5th mirror position in	16
			accordance with the selected magnification.
	M5	Toner Supply Motor	Rotates the toner bottle to supply toner to the	10
			development unit.
	M6	Optics Cooling Fan	Prevents build-up of hot air in the optics	17
		Motor	cavity.
		Exhaust Fan Motor	Removes heat from around the fusing unit
	M7		and blows the ozone built up around the	7
			charge corona unit towards the ozone filter.
	Clutches
	CL1	Tray Paper Feed	Transfers main motor drive to the paper feed	14
		Clutch	roller.
	CL2	By-pass Paper Feed	Starts paper feed from the by-pass feed	12
		Clutch	table.
	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	Interlock Switch	Cuts all power when the front cover is	37
			opened.
	SW3	Tray Paper Size	Determines what size of paper is in the	31
		Switch	paper tray.
	SW4	Right Vertical Guide	Cuts the +24 V dc power line of the relay	27
		Switch	roller clutch.
	Sensors
		4th/5th Mirror Home	Informs the CPU when the 4th/5th mirror
	S1	Position Sensor	assembly is at the home position (full size	33
			position).
	S2	ADS Sensor	Detects the background density of the	24
			original.

Information

Overall

1-9

ELECTRICAL COMPONENT DESCRIPTIONS			20 December 1996
Symbol	Name	Function		Index No.
S3	Tray Paper End	Informs the CPU when the paper tray runs		28
	Sensor	out of paper.
	Registration Sensor	Detects the leading edge of the copy paper
S4		to determine the stop timing of the relay		30
		roller clutch, and detects misfeeds.
S5	By-pass Feed Paper	Informs the CPU when there is no paper in		29
	End Sensor	the by-pass tray.
S6	Exit Sensor	Detects misfeeds.		23
S7	Scanner Home	Informs the CPU when the 1st scanner is at		40
	Position Sensor	the home position.
S8	Lens Home Position	Informs the CPU when the lens is at the		22
	Sensor	home position.
S9	Toner Density (TD)	Detects the ratio of toner to carrier in the		26
	Sensor	developer.
Printed Circuit Boards
PCB1	Main Control Board	Controls all copier functions.		1
	High Voltage Supply	Provides high voltage to the charge corona,
PCB2	Board - C/G/B/T/S	grid, development bias, transfer corona, and		2
		discharge plate.
	AC Drive/DC Power	Drives the exposure lamp, fusing lamp, and
PCB3	Supply Board	main motor. Rectifies 30 Vac and 8 Vac input		3
		and outputs 5 Vdc and 24 Vdc.
PCB4	Operation Panel	Informs the CPU of the selected modes and		6
	Board	displays the situation on the panel.
Lamps
	Erase Lamp	Discharges the drum outside of the image
L1		area. (Provides leading/trailing edge and		4
		side erases.)
L2	Quenching Lamp	Neutralizes any charge remaining on the		5
		drum surface after cleaning.
L3	Exposure Lamp	Applies high intensity light to the original for		20
		exposure.
L4	Fusing Lamp	Provides heat to the hot roller.		25
Others
CO1	Total Counter	Keeps track of the total number of copies		34
		made.
H1	Tray Heater (Option)	Turns on when the main switch is off to keep		32
		paper in the paper tray dry.
	Optics	Turns on when the main switch is off to
H2	Anti-condensation	prevent moisture from accumulating in the		39
	Heater (Option)	optics.
TF1	Exposure Lamp	Provide back-up overheat protection around		21
	Thermofuse	the exposure lamp.

1-10

20 December 1996 ELECTRICAL COMPONENT DESCRIPTIONS

Symbol	Name	Function	Index No.		Overall Information
TF2	Fusing Thermofuse	Provide back-up overheat protection in the	36
		fusing unit.
TH1	Fusing Thermistor	Monitors the temperature around the	35
		exposure lamp for overheat protection.
TH2	Optics Thermistor	Monitors the temperature around the	19
		exposure lamp for overheat protection.
TR	Transformer	Steps down the wall voltage to 30 Vac and 8	15
		Vac.

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).

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.

Detailed	Descriptions

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

2.1OVERVIEW

[A][B]

Detailed	Descriptions

[C] [D]

A219D505.wmf

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 (O3) 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
CN102-7	D C / D C			Detailed Descriptions
G N D
	Converter
CN102-6
C Trigger
CN102-5
T Trigger	D C / D C	G	C
	Converter
CN102-4
B - PWM	D C / D C		D r u m
	Converter
CN102-3				B
		S
	Zener			T
	Diode
S Trigger	D C / D C
	Converter
CN102-2
5 V
4.7 k	Protection
CN102-1
	Circuit
				A219D506.wmf

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]

[B]

[A]

[K]

[E]

[F]

[I]

[G]

[D]

[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

[F]

[D]

[H]

Detailed	Descriptions

[C]

[A]

[E] [G]

[B]

A219D522.wmf

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]	[D]
		[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.

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

3.4 4TH/5TH MIRROR DRIVE

[D]

[A]

[C]

[B]

OPTICS

Detailed	Descriptions

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.

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

+

VL Correction 1 Factor (SP62)

+

VL 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.

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.

Detailed	Descriptions

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
0	Normal	0	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:

	Darker								Lighter
Manual ID	1	2		3	4	5	6		7
Level
Exposure	V0 – 6		V0 – 4	V0 – 2		V0 + 2	V0 + 6		V0 + 12
Lamp Voltage					V0
	steps		steps	steps		steps	steps		steps
Factor
Development
Bias Voltage	–200		–200	–200	–200	–200	–240		–240
(Volts)
					V0: Base lamp voltage setting (SP48)

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

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, VL 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 correction

(Default setting: 2)

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) VL Correction 2 Factor

VL 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 VL correction 2 factor.

The sum of VL correction factors 1 and 2 cannot exceed +40 steps.

VL 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.)

Detailed	Descriptions

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

[A]

Detailed	Descriptions

A219D513.wmf

a b c d e f g h i j k l m

n

m l k j i h g f e d c b a

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 SIDE 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	Reproduction
			Ratio (%)
	None		99% to 200%
	a to b		95% to 98%
	a to c	11" x 17",	92% to 94%
		11" x 81/2"
	a to d		88% to 91%
	a to e	B4, B5	84% to 87%
		sideways
	a to f		80% to 83%
	a to g		75% to 79%
	a to h	81/2" x 11",	72% to 74%
		81/2" x 51/2"
	a to i	A4	68% to 71%
		Lengthwise
	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)	Lead Edge and Trail Edge
		Erase

-DF Mode-

	Blocks On	Paper Size	Reproduction
			Ratio (%)
	None		99% to 200%
	a to b		97% to 98%
	a to c	11" x 17",	93% to 96%
		11" x 81/2"
	a to d		90% to 92%
	a to e	B4, B5	86% to 89%
		sideways
	a to f		81% to 85%
	a to g		77% to 80%
	a to h	81/2" x 11",	73% to 76%
		81/2" x 51/2"
	a to i	A4	70% to 72%
		Lengthwise
	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)	Lead Edge and Trail Edge
		Erase

2-16