Ricoh NC8115.015 IMPORTANT SAFETY NOTICES

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 some components of the copier and the paper tray unit 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.If the hot roller temperature is low when the main switch is turned on, the copier starts process control self check automatically. Keep hands away from the mechanical and the electrical components to avoid any injury.

6.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.Never operate the copier without the ozone filters installed.

2.Always replace the ozone filters and the ozone neutralizers with the ones specified at the specified intervals.

3.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.

2.The RAM board on the main control board has a lithium battery which can explode if replaced incorrectly. Replace the battery only with an identical one. The manufacturer recommends replacing the entire RAM board. Do not recharge or burn this battery. Used batteries must be handled in accordance with local regulations.

ã 1995 By Ricoh Company Ltd. All rights reserved

SAFETY AND ECOLOGICAL NOTES FOR DISPOSAL

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

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

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

4.When keeping used lithium batteries in order to dispose of them later, do not put more than 100 batteries per sealed box. Storing larger numbers or not sealing them apart may lead to chemical reactions and heat build-up.

LASER SAFETY

The Center for Devices and Radiological Health (CDRH) prohibits the repair of laser-based optical units in the field. The optical housing unit can only be repaired in a factory or at a location with the requisite equipment. The laser subsystem is replaceable in the field by a qualified Customer Engineer. The laser chassis is not repairable in the field. Customer engineers are therefore directed to return all chassis and laser subsystems to the factory or service depot when replacement of the optical subsystem is required.

WARNING:

Use of controls, or adjustment, or performance of procedures other than those specified in this manual may result in hazardous radiation exposure.

WARNING FOR LASER UNIT

WARNING: Turn off the main switch before attempting any of the procedures in the Laser Unit section. Laser beams can seriously damage your eyes.

CAUTION MARKING:

SECTION 1

OVERALL MACHINE

INFORMATION

5 January 1995 DIFFERENCES

1. DIFFERENCES

DESCRIPTION

MODEL A092

MODEL A105

Reason for modification

SCANNER

Resolution

16 lines/mm (406.4 dpi)

400 dpi

To meet printer

standard.

CCD Drive

CCD Drive Board CCD

CCD Pre-amp Board

To ease servicing.

Board Set

Pre-amp Board and

has been eliminated.

Video Processing

CCD Drive Board and

Board

Video Processing

These boards have to

Board these two

be replaced as a set.

boards can be

replaced separately.

IMAGE PROCESSING

Gradation

64 gradation

6 bit

256 gradation

8 bit

To improve copy

Dithering

Letter: 2 x 2

Letter: 1 x 1

quality.

Pattern Matrix

Photo/Letter: 3 x 3

Photo/Letter: 2 x 1

Photo: 4 x 4

Photo: 2 x 2

RGBγ

To meet the new type

L

H

L

H

Parameter

R

6

5

R

8

7

toner.

G

5

5

G

8

6

B

7

5

B

9

6

Memory

18 MBytes (1M x 144)

64 MBytes (4M x 128)

An image defined at 8

bits per pixel requires

much more memory

than one defined at 3

bits per pixel.

4 Color

Image repeat

The functions at left

To improve the copy

Developing

Edit image

can now use black

quality.

(Y, M, C, Bk)

These cannot use

developing.

black developing.

LASER

Gradation

64 steps by using

256 gradation

To improve the copy

dither matrix

(256 steps/pixel)

quality.

(8 steps/pixel)

Polygon Motor

9000 rpm

8858.3 rpm

As the resolution has

Rotation Speed

been changed from

406.4 dpi to 400 dpi.

Horizontal

Adjusted by DGSs on

Adjusted keys on the

To ease servicing.

Magnification

the drum exposure

operation panel. (SP

&

control board.

mode)

Printing Start

Adjustment

Method

1-1

DIFFERENCES			5 January 1995
DESCRIPTION	MODEL A092	MODEL A105	Reason for modification
ID SENSOR

ID Sensor	ID sensor is set on the
	casing of the
	development unit.

ID sensor is set on the casing of the copier.

When replacing the development unit, it is not necessary for model A105 to perform Vmin check.

Because, the ID sensor is set separately from the casing of the development unit.

DEVELOPMENT UNIT

Unit Separation Cannot be separated	Can be separated the	To replace the toner
sub-tank from	sub-tank [A] from the	supply roller [C].
main-tank.	main-tank [B]

[A]

		[C]
		[B]
Developer for	Uncoated ferrite carrier.	Silicon coated ferrite	To prolong the life of
all colors		carrier.	the developer.
			15K → 20K
			To increase the charge
	250 g/bag	200 g/bag	ability of the developer.
Toner	12 μm	6.4 μm	To improve the
Diameter for			resolution of copy
all colors			image.
Toner Supply	Rubber roller	Silicon rubber roller	To improve toner
Roller			supply capacity.

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5 January 1995			DIFFERENCES
DESCRIPTION	MODEL A092	MODEL A105	Reason for modification
Cross-mixing		Add upper auger [A]	To stabilize the image
Mechanism		and upper transfer	density.
		roller [B].	To eliminate the
			un-even density band
		[A]	(12 mm/0.47 inch
			pitch).
		[B]	To power up the mixing
			function.

Bias	–DC (–278V –678V)	–DC+AC	To get uniform density
		DC (–278V –678V)	on copies.
		AC (1 kV peak to peak)
Development	Drum speed : Sleeve	Drum speed : Sleeve
Sleeve Speed	speed = 1 : 2.3	speed = 1 : 1.6
TRANSFER UNIT
Transfer Drive	Low impedance	High impedance	To insure cyan toner is
Roller			transferred to the copy
Transfer Belt			paper.
Discharge

CLEANING UNIT

Cleaning	Trailing blade	Counter blade	The new toner consists
Method			of smaller particles.
			To remove the smaller
			particles of the new
			toner and to improve
			the durability of the
			cleaning blade.

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DIFFERENCES				5 January 1995
DESCRIPTION		MODEL A092	MODEL A105	Reason for modification
PAPER FEED UNIT

Paper Feed	This mechanism has
Unit Parallel	been applied by the
Adjustment	engineering change.
Mechanism [A]

This mechanism has been applied from the 1st production run.

[A]

To adjust the skew and the color layer alignment at the trailing edge.

FUSING

Hot Roller	Not Used	A cleaning roller and	To increase durability
Cleaning		cleaning scraper have	of fusing unit.
Mechanism		been added.

NOTE: This is not a complete list of the differences between the model A092 and A105, but does illustrate the major differences.

1-4

5 January 1995 SPECIFICATIONS

2. SPECIFICATIONS

Configuration:	Console type
Copy Process:	Laser electrostatic transfer/tetradrive system
Originals:	Book/sheet, fixed platen
Original Alignment:	Front-right corner
Maximum Original Size:	A3, 11" x 17"
Copy Paper Size:	Maximum:	A3, 11" x 17
	Minimum:	A6 (lengthwise only), 51/2" x 81/2"
Copy Paper Weight:	64 to 157 g, 17 to 42 lb
	(Paper with more than 128 g/34 lb and OHP film
	should be used with Thick Paper/OHP mode.)
Copy Speed:	<Model A092>
	14.5 cpm/81/2" x 11" sideways, or smaller
	15 cpm/A4, sideways, or smaller
	7.5 cpm/A3, 11" x 17"
	<Model A105>
	15 cpm/81/2" x 11" sideways, or smaller
	15 cpm/A4, sideways, or smaller
	7.5 cpm/A3, 11" x 17"
	(In thick paper/OHP mode, copy speed is reduced
	to one half.)
First Copy:	18 seconds/A4, 81/2" x 11" sideways
	(In thick paper/OHP mode, it is 35 seconds.)
Warm-up Time:	Within 8 minutes (at room temperature 20°C/68°F)
Copy Counter:	1 to 99
	(Maximum set number is adjustable with SP38.)
Automatic Reset:	After 60 seconds (Adjustable from 1 to 180
	minutes, or no reset with SP37.)
Photo Conductor:	Organic photoconductor (OPC) drum, 60 mm in
	diameter, 4 drum system driven by a dc servo
	motor through a single drive shaft (tetradrive).
Drum Charge:	Single wire with grid plate (negative charge),
	variable grid voltage type.

1-5

SPECIFICATIONS 5 January 1995

Fixed Reproduction				5 enlargement ratios and 7 reduction ratios
Ratios:
			Letter Version					A4 version
	1	: 4.00	400% copy		1	: 4.00		400% copy
	1	: 2.00	51/2" x 81/2" Þ 11" x 17"		1	: 2.00		A5 Þ A3	A6 Þ A4
	1	: 1.55	51/2" x 81/2" Þ 81/2" x 17"		1	: 1.41		A4 Þ A3	A5 Þ A4
	1	: 1.29	81/2" x 11" Þ 11" x 17"		1	: 1.22		F Þ A3	A4 Þ B4
	1	: 1.21	81/2" x 14" Þ 11" x 17"		1	: 1.15		B4 Þ A3
	1	: 1	100% copy		1	: 1		100% copy
	1	: 0.93	To create margin		1 : 0.93			To create margin
	1	: 0.85	81/2" x 13" Þ 81/2" x 11"		1	: 0.82		F Þ A4	B4 Þ A4
	1	: 0.77	81/2" x 14" Þ 81/2" x 11"		1	: 0.75		B4 Þ F4	B4 Þ F
	1	: 0.74	11" x 15" Þ 81/2" x 11"		1	: 0.71		A3 Þ A4	A4 Þ A5
	1	: 0.65	11" x 17" Þ 81/2" x 11"		1	: 0.65		A3 Þ F
	1	: 0.50	11" x 17" Þ 51/2" x 81/2"		1	: 0.50		A3 Þ A5	A4 Þ A6
	1	: 0.25	25% copy		1	: 0.25		25% copy
				Reproduction error:
				±0.5% for full size mode, ±1.0% for other ratios.
Zoom:				From 25% to 400%, 1% steps
				(In thick paper/OHP mode, from 25% to 200%)
Scanning System:				One way scanning with optical fiber array and full
				size color CCD’s, single scan with simultaneous
				B, G, R, color separation.
				<Model A092> 16 dots/mm, 256 gradation
				<Model A105> 400 dpi, 256 gradation
Scanner Light Source:				Two fluorescent lamps
Drum Exposure System:				4 semiconductor laser beams (1 laser beam per
				OPC drum), one dimensional simultaneous
				scanning onto 4 drums with one polygon
				motor/two polygon mirrors.
				<Model A092> 16 dots/mm, 64 gradations
				<Model A105> 400 dots/inch, 256 gradations
Development:				Dual component dry toner/single development
				roller system. (Negative toner charge/Negative
				drum charge process.)
Developer:				<Model A092>

-Bk, Y, C: 250 g/bag

-M: 200 g/bag (same as that of model A105)

<Model A105>

- Bk, M, Y, C: 200 g/bag

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5 January 1995	SPECIFICATIONS
Toner:	<Model A092>
	- Bottle Type: 400 g/bottle
	- Consumption: 9000 copies/A4, 81/2" x 11"
	(5% image area for each color)

<Model A105>

-Bottle Type: 340 g/bottle

-Consumption: 7000 copies/A4, 81/2" x 11" (5% image area for each color)

Development Bias:	<Model A092> Negative dc variable bias
	<Model A105>Negative dc and ac variable bias
Image Transfer:	Single wire dc positive charge from the reverse
	side of the transfer belt.
Paper Transport:	One flat transfer belt system
Paper Separation:	Primary:	Paper curvature separation
	Secondary: Pick-off pawls, and single wire
		separation ac corona for paper
		discharge.
Transfer Belt Discharge:	<Model A092>		Single wire ac corona
	<Model A105>		Single wire ac corona and
			discharge roller
Transfer Belt Cleaning:	Blade and brush cleaning
OPC Drum Cleaning:	<Model A092>		Trailing blade and brush
			cleaning
	<Model A105>		Counter blade and brush
			cleaning
Quenching:	Photo quenching by LEDs
Paper Feeding:	Dual cassettes (500 sheet capacity each), and a
	bypass feed table (20 sheets)
Paper Feed System:	Feed and reverse roller (FRR) system
Image Fusing:	Heat and pressure type with silicone oil. Silicone
	hot-roller, and silicone pressure roller.
Fusing Lamp:	Halogen lamp (220 – 240 V/550 W, 115 V/550 W)
Silicone Oil Consumption:	350 cc per 35,000 copies (A4/81/2" x 11")
Copy Tray Capacity:	100 sheets

1-7

SPECIFICATIONS		5 January 1995
Self-diagnostic Codes:	72 codes
Process Control:	Drum potential control
	Development bias control
	Toner supply roller bias control
Copy Counters:	Two counters (Double count mode for A3/DLT
	can be set with SP45.)
	∙ Single color copy counter (including black)
	∙ Full color copy counter
User Code Mode:	20 4 digits numbers from 0001 to 9999
Power Source:	220 – 240 V/50 Hz: 8 A
	115 V/60 Hz:	12 A
Power Consumption:	Maximum:	1.4 kW
	Warm-up:	0.9 kW (average)
	Ready:	0.5 kW (average)
	Copy cycle: 1.0 kW (average)
Dimensions (W x D x H):	Main frame only: 930 mm x 725 mm x 930 mm
		(36.6" x 28.5" x 36.6")
	With platen cover, copy tray, and A3/DLT
	cassette in the lower feed section:
		1695 mm x 725 mm x 954 mm
		(66.7" x 28.5" x 37.6")
Weight:	Main frame only without consumables:
	<Model A092> 285 kg (628.3 lbs) or less
	<Model A105> 285 kg (628.3 lbs) or less
	Main frame with consumables:

<Model A092> 296 kg (652.6 lbs) or less

<Model A105> 300 kg (661.4 lbs) or less

Optional Equipment:	- Editor
	- SPU

(This is standard for Model A105.)

SPU(Model A984-27) can only be connected

to Model A092-25 and A092-27.

SPU (Model A711-27) can be connected to Model A105-25 and A105-27. SPU(Model A984-17) can be connected to Model A092-17 and A105-17.

- Key counter (locally procured)

1-8

5 January 1995	SPECIFICATIONS
<Additional Features>
User Program Mode:	5 modes (The image repeat mode and the poster
	mode can not be stored as a program mode.)
Original Recognition	The default is the Off mode. Using SP-31, the On
Mode:	mode can be selected. In APS/ARE, Centering,
	Mirroring, Slanted Image modes, the On mode is
	automatically selected.
Color Selection:	The default is Full Color. Using SP-44, the Black
	mode can be selected as the default mode.
	Single color: 9 kinds
	black, yellow, orange, red, magenta, blue,
	cyan, green, light green.
	Optional single color:
	3 user programmable colors can be registered.
Original Modes:	4 modes
	- Automatic Letter/Photo separation (Auto)
	mode: Default
	- Letter mode
	- Letter/Photo mode
	- Photo mode
	The default mode can be changed by SP40, and
	41.
	In the Auto mode, photo areas are processed
	using the Photo mode as a default.
	(It can be changed from Photo mode to
	Letter/Photo mode with SP43.)
APS:	Pre-scanning type
Paper Weight:	Thick Paper/OHP mode:
	Process speed is changed from 75 mm/sec. to
	37.5 mm/sec. This mode is for paper that is
	128 g/34 lb or heavier and for OHP film.
	Thin Paper:
	The fusing temperature during the copy run is
	controlled at 143°C (131°C for model A105) rather
	than 148°C (135°C for model A105). (By SP42,
	the default mode can be set at the Thin Paper
	mode.)

1-9

SPECIFICATIONS	5 January 1995
Special Reduce/Enlarge:	- ARE (Auto Reduce/Enlarge)
	- Directional size magnification
	- Directional magnification
	- Size magnification
	- Zoom
Edit Image:	- Centering
	- Save area
	- Delete area
Image Creation:	- Outline mode
	- Positive/Negative mode
	- Shadow mode
	- Image Repeat mode
	- Mirror Image mode
	- Slanted Image mode
	- Poster mode (Model A105 only)
Color Creation:	- Color Background mode
	- Color Conversion mode
	- Pastel Image mode
	- Posterization mode
	- Solarization mode
	- Mosaic mode

<Image Adjustments>

Image Density Selection: 9 steps

Color Balance:	For black, cyan, magenta, and yellow, adjustable
	in 9 steps. Adjusted balance can be stored as a
	default setting by pressing the Balance Memory
	key.
Color Adjustment:	Color tone of green, cyan, blue, magenta, red, or
	yellow can be independently adjusted to one of
	the neighboring colors. This can be done with up
	to three colors.
Sharp/Soft:	Adjusts the sharpness of the copy image.
Contrast:	Adjusts the contrast between light and dark parts
	of the copy image.
Background Density	Adjusts background image density of the copy.
Control:

1-10

5 January 1995							SPECIFICATIONS
User Tool/Service Tool:
<Model A092>
For users						10 user tools (UT-1 to UT-10) for 115 V version
For service						11 user tools (UT-1 to UT-11) for 230 V version
						SP mode (SP-1 to SP-92)
						SPT/SPD mode
							SP Test mode (SPT-0 to SPT-119)
<Model A105>							SP Data mode (SPD-1 to SPD-898)
For users						11 user tools (UT-1 10 and 12) for 115 V version
						12 user tools (UT-1 12) for 230 V version
For service						SP mode (SP-1 to SP-95)
						5 SP modes have been added from model A092.
						SPT/SPD mode
							SP Test mode (SPT-0 to SPT-119)
							SP Data mode (SPD-1 to SPD-898)

1-11

COPY PROCESS

5 January 1995

3. COPY PROCESS

3.1 OVERVIEW

[E]

[D]

[C]

[B]

[A]

The main marketing strengths of this copier are:

1)High productivity with the world’s fastest digital full color copy speed

(15 cpm/A4, 14.5 cpm/LT: Model A092, 15 cpm/A4, LT: Model A105).

2)A wide variety of copy paper can be used, such as heavy paper (up to 157 g/42 lb), and small paper (up to A6 lengthwise or 51/2" x 81/2").

To achieve this productivity, this machine adapts four OPC drums, four laser beams, and one time scanning with a simultaneous B, G, R, (Blue Green Red) color separation system (tetradrive system). Paper is transported on a flat transfer belt [A] where the toner image on each drum is transferred to the paper in order. These four layers of color toner image are fused on the paper.

For compactness, each drum is 60 mm in diameter, and they are located at

110 mm intervals. From the right side, the drums are: black [B], magenta [C], yellow [D], and cyan [E]. Each drum has the following components around it:

∙Charge corona unit

∙Development unit

∙ID sensor

∙Transfer corona unit (below the transfer belt)

∙Drum cleaning unit

∙Quenching lamp (LEDs)

1-12

5 January 1995

COPY PROCESS

3.2 SCANNING

3.2.1 Original Scanning

The color original is illuminated by two exposure lamps [A]. Reflected light from the original passes through the optical fiber array [B] to the full size color CCD [C].

(CCD = Charge coupled device)

The CCD converts the light intensity to an electrical value.

The scanner which is composed of the exposure lamps, optical fiber array, and

CCD, is always in contact with the exposure glass while scanning.

3.2.2 Photo-electric Conversion

The full size color CCD has blue, green, or red filters on each picture element

(pixel) in a line. Three elements, with the filters for each color, are used as one unit for color separation of the original image.

<Model A092>

16 pixels per 1 mm = 406.4 pixels per inch (DPI)

<Model A105>

400 pixels per inch (DPI)

The CCD converts the light intensity into an electrical analog signal.

3.2.3 Analog-digital Conversion

[A]

[B]

[C]

1	2		3		2880/chip

B G R B G R B G R

62.5 μ (Model A092)

63.5 μ (Model A105)

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

3.2.4 RGB Separation

Signals from the 14,600 picture elements are separated into three groups of red, green, and blue picture elements.

1-13

COPY PROCESS

5 January 1995

3.2.5 Image Processing

Image processing for various copy modes is done in the image processing PCB’s.

The 8-bit gradation digital data for one set of red, green and blue elements is changed to the data for four toner colors:

	Black data (Bk)
Green data (G)	Magenta data (M)
Blue data (B)	Yellow data (Y)
Red data (R)	Cyan data (C)

Filter	B	G	R
Toner	Y	M	C

	200
150
		100			120
			80
80				70
						20
C	M	Y	Bk	C	M	Y

(UCR Ratio: 80%)

The black output is determined by the CMY data (which is a result of the RGB data). A common value is subtracted from the C, M, and Y values and this value becomes the black value. This is called UCR (Under Color

Removal).

<Model A092>

There are 8 laser exposure gradation steps (7 levels + laser off), so only 3 data bits are needed. The four color data are converted from 8-bits to 3-bits.

64 kinds of 4 x 4 bit dither matrices (Photo mode) are used to make 64 gradations of the copy image.

<Model A105>

There are 256 laser exposure gradation steps (255 levels + laser off), so 8 data bits are needed. One pixel can make 256 gradations of the copy image.

1-14

5 January 1995

COPY PROCESS

3.3 LASER EXPOSURE

1.There are four laser beams (one beam per drum) and two polygon mirrors in the laser unit. The two polygon mirrors are turned using one motor.

The laser beam is reflected by the turning polygon mirror, and passes through a complex lens (called the fθ lens) to the drum.

Using one surface of the polygon mirror, one main scan line is made. The main scan direction is:

1st (black) and 2nd (magenta) drums: front to rear. 3rd (yellow) and 4th (cyan) drums: rear to front.

2.The laser beam switches on and off at very high frequency to make an image with 16 dots/lines per 1 mm (400 dpi for Model A105).

<Model A092>

Furthermore, the on-time (PWM) per dot for the laser beam is controlled in 8 steps based upon the 3-bit data sent from the image processing unit.

<Model A105>

Furthermore, the on-time per dot for the laser beam is controlled 256 steps based upon the 8-bit data sent from the image processing unit.

As a result, the negatively charged drum potential drops to the appropriate level, forming an electrical latent image on the drum.

Unlike other PPCs, the exposed areas correspond to the dark image areas on the original (image area exposure).

3.The data for black is sent just after image processing to the laser unit for laser exposure on the black drum.

However the data for the other three colors is stored in the memory board, and is sent to the laser unit at the appropriate time. This is to align the horizontal direction of the image developed on each of the four drums.

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COPY PROCESS 5 January 1995

3.4 DRUM PROCESSES

		<Model A092>		<Model A105>
		[D]		[D]
		[B]		[B]
	[A]	[F]	[A]	[F]
	[K]	[E]	[K]	[E]
		[C]	[I]	[C]
		[G]		[G]
	[I]	[H]
			[J]	[H]
	[J]

3.4.1 Charge

<Model A092 & A105>

In the dark the charge corona unit [A] applies a negative charge to the drum.

The grid plate [B] ensures that the charge is applied uniformly and that the amount of the charge applied is correct. The charge remains on the surface of the drum because the photoconductive drum has a high electrical resistance in the dark.

3.4.2 Development

<Model A092 & A105>

The magnetic developer brush on the development roller [C] comes in contact with the latent image on the drum surface. Negatively charged toner particles are electrostatically attracted to the areas of the drum surface where the laser [D] has reduced the negative charge on the drum.

Unlike most PPCs, this machine uses a Negative/Negative development system. (Negative/Negative: Negative toner developed on a negatively charged drum.)

Another unique point is how the toner is supplied to the developer. Toner is supplied in an even and thin layer on the supply roller [E] using a metering blade [F].

While toner is passing the metering blade, the toner becomes negatively charged, and is caught by the positively charged carrier in the development unit.

1-16

5 January 1995

COPY PROCESS

3.4.3 ID Sensor

The ID sensor [G] is used to detect the different kinds of patterns developed on the drum. It has two basic functions.

It’s used to control the density of toner in the developer.

It’s used to select the best process conditions such as, charge grid voltage [V0], development bias [VB] and laser power (remaining or residual drum voltage after level 3 exposure [VL3]:

A092/ level 4 exposure [VL4]: A105).

V0 (= V L0)

VB

VL1

VL3

VL7

Development Potential : VB – VL3

3.4.4 Image Transfer

Copy paper is fed to the transfer belt [H] by the registration rollers. A positive charge is applied to the backside of the paper through the transfer belt. This charge pulls the toner particles on the OPC drum surface onto the copy paper.

After the first toner transfer (black), the entire copy paper is electrically held on the belt’s surface.

Transfer charge for magenta, yellow, and cyan is stepped up to pull a new color toner layer onto the paper.

3.4.5 Paper Separation

The paper’s stiffness causes it to separate from the transfer belt when the belt turns sharply at the separation point. This is called "curvature separation". To ensure separation of paper that has low stiffness, this machine also uses a separation corona, for paper potential discharge, and pick-off pawls. Three pick-off pawls touch the belt just before the leading edge of the paper reaches the pick-off position.

3.4.6 Drum Cleaning and Quenching

The cleaning blade [I] and cleaning brush [J] remove any toner remaining on the drum surface and the toner is carried to the toner collection bottle.

The quenching lamp (LEDs) [K] electrically neutralize the surface of the drum.

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COPY PROCESS

5 January 1995

3.4.7 Transfer Belt Discharge and Cleaning

After paper separation, the residual electrical potential is discharged by the belt discharge corona. Then, any toner remaining on the belt surface is removed by the belt cleaning brush and blade.

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5 January 1995

COPY PROCESS

3.5 NEGATIVE/NEGATIVE DEVELOPMENT PROCESS

VL1 : VL7
Drum voltage on the			[A]
image areas
(exposed by laser).
V0 :
Drum voltage on the
nonimage areas			VB
(background).
<Model A092>			<Model A105>

Example = Pointer 10

V0: –510V

Development

VB: –408V

Potential

VL3: –282V

Example = Pointer 22

V0: –698V

VB: –561V

VL3: –396V

Development

Potential

Most copiers use either a positively charged photoconductor and negatively charged toner or a negatively charged photoconductor and positively charged toner. This is known as positive/negative development. However, this machine uses a negative/negative process where both the drum surface charge and the toner charge are negative.

Several forces interact in the development process to produce a visible image on the OPC drum. These forces are the charge pattern of the latent image, the development bias, the magnetic field of the development roller, the positive triboelectric charge of the carrier, and the negative triboelectric charge of the toner.

One of the most important of these forces is the charge pattern of the latent image on the drum. To make the latent image, the laser exposes an area of the drum surface. The laser on-time for one pulse is controlled using a pulse width modulation circuit (PWM).

<Model A092>

The on-time is determined according the 3-bit data sent from the IPU (10 120 nsec).

<Model A105>

The on-time is determined according to the 8-bit data sent from the IPU (2 86 nsec).

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COPY PROCESS

5 January 1995

VD: Drum charge potential

V0: Non exposed area (Non image area on original) = VD

<Model A092>

V0: Remaining drum voltage at laser data 0 (No laser exposure) VL1: Remaining drum voltage at laser data 1 (Shortest phase)

|

VL7: Remaining drum voltage at laser data 7 (Full phase)

<Model A105>

V0: Remaining drum voltage at laser data 0 (No laser exposure)

VL1: Remaining drum voltage at laser data 34

VL2: Remaining drum voltage at laser data 46 VL3: Remaining drum voltage at laser data 63 VL4: Remaining drum voltage at laser data 80 VL5: Remaining drum voltage at laser data 127 VL6: Remaining drum voltage at laser data 191

VL7: Remaining drum voltage at laser data 255 (Longest phase)

256 step laser exposure is used for copying. 7 step (VL1 VL7) laser exposure is for process control.

<Model A092 & A105>

The power pack for each drum applies a dc negative bias [VB] (75 160 V lower than V0) to the development roller sleeve. The main magnet [A] is located inside the sleeve, facing the drum.

The toner is negatively charged and the carrier is positively charged due to the agitation of the toner and developer inside the development unit (tribo electric charge).

In a negative/negative process, toner particles are attracted to the drum areas exposed by the laser hence, to the lower drum potential areas.

Development potential is the gap from VB (bias) to VLX (Laser exposed area, X=1 to 7).

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5 January 1995

COPY PROCESS

In the development area, the following forces act on the toner particles:

Fc: The attractive force between toner

(–) and carrier (+)

FD: The repelling force between toner

(–) and the drum charge (–)

FB: The repelling force between the toner (–) and the development roller bias (–)

The forces on the exposed areas of the drum are such that:

FB > FC + FD (Fig. 1)

DRUM	DEV.
	ROLLER
VL
	Carrier
	Toner
	FB
	Fc
	FD

BIAS

Fig. 1

This means toner is repelled from the carrier to the drum. (FD is very small in the image areas.)

The non-exposed areas of the drum are such that.

FB < FC + FD (Fig. 2)

Here FD is very large and repels toner from the non image areas.

You might expect that the positively charged carrier would be attracted to the negatively charged nonimage areas of the drum. However, this does not happen. In the development area, the following forces act on the carrier particles:

FMC: The attractive force of the magnet on the carrier

FBC: The attractive force between the carrier and development bias

FDC: The attractive force between the carrier (+) and the non-exposed areas of the drum (–)

Since FDC < FMC + FBC (Fig. 3), the carrier remains on the development roller’s sleeve.

DRUM	DEV.
	ROLLER
VD
	Carrier
	Toner
	FB
	Fc
	FD

BIAS

Fig. 2

DRUM		DEV.
		ROLLER
VD	Carrier
		MAGNET
	FBC
	FMC
	FDC
		BIAS

Fig. 3

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COPY PROCESS

5 January 1995

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

In a negative/negative process, some copy problems are exactly opposite to what many copier service people have intuitively come to expect. The table below gives some of the differences between the positive/negative process and the negative/negative process.

	Positive/Negative		Negative/Negative
Type of Laser	He-neon	He-neon or	Semiconductor
	(gas, 630 nm)	semiconductor	(765 795 nm)
Photoconductor	Se Drum	OPC	OPC
Charge Corona	Positive	Negative	Negative

Carrier Charge		Positive	Negative	Positive
Toner Charge		Negative	Positive	Negative
Photoconductor		Background exposure		Image exposure
Exposure			P	P
P: Pitch (1/16mm +		D
62.5μ for model		P
μ	for			P
A092, 63.5
model A105)
D: Laser beam
diameter
VD: Drum voltage			VD	VD
VB: Bias voltage				VB
VR: Residual voltage
			VB
			VR
			0V	0V
Copy Problems
1. No photoconductor		White copy		Black solid copy
charge

2.	Low photoconductor	Low image density	Dirty background
	charge
3.	High development	Low image density	Dirty background
	bias
4.	Low development	Dirty background	Low image density
	bias
5.	Stained toner shield	Black stripes	White stripes
	glass

1-22

5 January 1995

MECHANICAL COMPONENT LAYOUT

4. MECHANICAL COMPONENT LAYOUT

1

2

3

4

5

6

7

28

27

26

25

	8
24
23	9

22

10

11

21

20

19

18

17

16

15

14

13

12

1-23

MECHANICAL COMPONENT LAYOUT

5 January 1995

1.Laser Unit

2.Polygon Motor

3.Polygon Mirrors (2 pcs)

4.Scanner Unit

5.Scanner Motor

6.Scanner

7.IPU Section (7 PCB’s)

8.By-pass Table

9.Upper Cassette

10.Lower Cassette

11.Paper Feed Unit

12.Transfer Belt Cleaning Unit

13.Transfer Belt Unit

14.Black OPC Drum

15.Magenta OPC Drum

16.Yellow OPC Drum

17.Cyan OPC Drum

18.Toner Collection Bottle

19.Transfer Corona (4 pcs)

20.Belt Discharge Corona

21.Developer Catch Pan

22.Copy Tray

23.Fusing Unit

24.Separation Corona

25.Fusing Exhaust Fan (2 pcs)

26.Exit Ozone Filters (2 pcs)

27.Dust Filter

28.Ozone Neutralizer

1-24

5 January 1995

DRIVE LAYOUT

5. DRIVE LAYOUT

14 13

15

16

17

18
19
20	12
21	11
22

23

24

25

26

1

2

3

4

10

9

8

7

27

28

6

5

1-25

DRIVE LAYOUT

5 January 1995

1.Toner Collection Coil Drive Belt

2.1st Timing Belt

3.Main Motor

4.2nd Timing Belt

5.Developer Removal Motor

6.3rd Timing Belt

7.Fusing Unit Drive Gear

8.Transfer Belt Drive Worm Wheel

9.Transfer Belt Drive Timing Belt

10.Transfer Belt Drive Motor

11.Drum Drive Worm Wheel (4 pcs)

12.Drum Drive Worm Gear (4 pcs)

13.Cleaning Unit Drive Gear (4 pcs)

14.OPC Drum Shaft (4 pcs)

15.Toner Supply Clutch (4 pcs)

16.Toner Supply Drive Gear (4 pcs)

17.Development Unit Drive Gear

(4 pcs)

18.Drum Drive Motor

19.Drum Drive Timing Belt

20.Paper Feed Motor

21.Upper Paper Feed Clutch

22.Upper Lift Motor

23.Lower Paper Feed Clutch

24.Lower Lift Motor

25.Relay Clutch

26.Registration Clutch

27.Fusing Unit Idling Motor (Model A105 only)

28.Fusing Idling Gear (Model A105 only)

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5 January 1995

ELECTRICAL COMPONENT DESCRIPTIONS

6. ELECTRICAL COMPONENT DESCRIPTIONS

Refer to the electrical component layout on the reverse side of the point to point (water proof sheet).

SYMBOL	NAME	FUNCTION	LOCATION
MOTORS
M1	Scanner Motor	Drives the scanner ( dc servomotor).	53
M2	Polygon Motor	Turns two polygon mirrors (dc servomotor).	71
M3	Main Motor	Drives the development units, cleaning units,	12
		toner collection coil, belt cleaning unit, and
		fusing unit.
M4	Drum Motor	Turns the four OPC drums (dc servo motor).	10
M5	Transfer Belt	Turns the transfer belt (dc servomotor).	6
	Motor
M6	Paper Feed Motor	Drives the paper feed rollers, relay rollers,	113
		registration rollers.
M7	Upper Lift Motor	Lifts the upper cassette’s bottom plate.	93
M8	Lower Lift Motor	Lifts the lower cassette’s bottom plate.	99
M9	Toner Supply	Supplies black toner from the toner supply unit	123
	Motor – Black	to the toner container in the development unit.
M10	Toner Supply	Supplies magenta toner from the toner supply	125
	Motor – Magenta	unit to the toner container in the development
		unit.
M11	Toner Supply	Supplies yellow toner from the toner supply	127
	Motor – Yellow	unit to the toner container in the development
		unit.
M12	Toner Supply	Supplies cyan toner from the toner supply unit	129
	Motor – Cyan	to the toner container in the development unit.
M13	Developer	Is used when developer is removed from the	2
	Removal Motor	development units.
M14	Front Scanner	Cools the scanner cavity.	65
	Fan
M15	Rear Scanner Fan	Cools the scanner cavity.	58
M16	Front IPU Inlet	Cools the IPU cavity by taking air from outside	23
	Fan	the copier.
M17	Rear IPU	Cools the IPU cavity by blowing hot air out of	11
	Exhaust Fan	the copier through an ozone filter.
M18	Rear Exhaust Fan	Always turns during power on to cool the air	4
		around the fusing unit.
M19/20	Fusing Exhaust	Cool the air around the fusing unit and OPC	44
	Fans (2 pcs)	drums through ozone filters during copy run.
M21	Charge Fan	Provides a flow of air to the charge corona	8
	– Black	unit, ID sensor, and the toner shield glass.
M22	Charge Fan	Same function as M21.	8
	– Magenta

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