Ricoh ap204 Service Manual pom e

POMELO (G033)

SERVICE MANUAL

[Engine]

øIMPORTANT SAFETY NOTICES

PHYSICAL INJURY PREVENTION

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

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

3.Note that some printer components are supplied with electrical voltage even if the main switch is turned off.

4.If an adjustment or operation check must be made requiring the removal or opening of the exterior covers while the main switch is on, keep hands away from electrified or mechanically driven components.

5.The printer drives some of its components when it completes the warm-up period. Keep hands away from mechanical and electrical components when the printer starts operation.

6.The interior and metal parts for the fusing unit become extremely hot while the printer is operating. Do NOT touch these components with bare hands.

HEALTH SAFETY CONDITIONS

1.Never operate the printer without ozone filters installed.

2.Always replace the ozone filters with the specified replacement at the specified maintenance intervals.

3.Toner is non-toxic, but if it gets in your eyes by accident, it may cause temporary eye discomfort. Remove it with eye drops or flush eyes with water. If this is unsuccessful, get medical attention immediately.

SAFETY AND ECOLOGICAL NOTES FOR DISPOSAL

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

2.Dispose of used toner and belt cartridge in accordance with local regulations. (These are non-toxic supplies.)

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

LASER SAFETY

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

øWARNING

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

øWARNING

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

CAUTION MARKING:

Trademarks

Microsoft, Windows 98/95/3.1x, and Windows NT 4.0 are registered trademarks of Microsoft Corporation.

Macintosh and AppleTalk are registered trademarks of Apple Computer, Inc.

NetWare is a registered trademark of Novell, Inc.

Ethernet is a registered trademark of Xerox Corporation.

General Notice:

Other product names used herein are for identification purposes only and may be trademarks of their respective companies. We disclaim any and all rights in those marks.

25 December, 1998

SPECIFICATIONS

1. OVERALL MACHINE INFORMATION

1.1 SPECIFICATIONS

Configuration	Desk top
Print Process	Laser beam and dry toner electrostatic photograph system
Resolution	600 dpi
Paper Size	Tray 1
	A4, JIS B5, 81/2” x 11”, 7 1/4” x 101/2” (Executive Size),
	and Custom Size paper (Length: 210 to 297 mm, Width:
	100 to 216 mm)
	Tray 2 (Optional Paper Feed Unit)
	A4, JIS B5, 81/2” x 11”, 7 1/4” x 101/2”
	Optional Paper Tray
	A4, JIS B5, 81/2” x 11”, 7 1/4” x 101/2” (Executive Size),
	81/2” x 14”, and Custom Size paper (Length: 210 to 356
	mm, Width: 100 to 216 mm)*
	* The optional paper tray can be used as tray 1 or tray 2.
	Custom sizes can only be used in this tray if it is in the
	tray 1 position.
Paper Weight	60 to 160 g/m2 (16 to 43 lbs.)
	Plain paper mode: 60 to 90 g/m2
	Thick paper mode: 90 to 160 g/m2, adhesive labels
	OHP transparency mode: OHP transparencies
Print Speed	Plain Paper
	Monochrome: 16 ppm (A4 portrait)
	Color: 4 ppm (A4 portrait)
	OHP and Thick Paper
	Monochrome: 8 ppm OHP and 3 ppm Thick (A4 portrait)
	Color: 2 ppm OHP and Thick (A4 portrait)
Warm-up Time	Less than 210 seconds (at 23°C/73°F)
First Printout Time	Monochrome: Less than 19 seconds
	(A4/81/2” x 11”, Tray 1)
	Color: Less than 30 seconds (A4/81/2” x 11”, Tray 1)
Paper Capacity	Tray 1 and tray 2: 250 sheets (80 g/m2, 20 lbs.)
Paper Output	250 sheets (80 g/m2, 20 lbs.)
Capacity
Output Method	Face down
Power Supply	120 V ±10%, 50/60 ±2Hz, more than 8.3 A
	220-240 V ±10%, 50/60 ±2Hz, more than 4.5 A

Overall Information

1-1

SPECIFICATIONS	25 December, 1998
Power Consumption	Maximum: 1000 W (Energy Star compatible)
	Average during printing: 450 W (Maximum)
	Average during energy saver mode: 30 W (Maximum)
Noise Emission	Standby: Less than 48 dB
(Sound Power Level)	Operating: Less than 55 dB
Dimensions	500 x 490 x 399 mm (19.7” x 19.3” x 15.3”)
	(without optional tray unit)
Weight	Approximately 36 kg (79.4 lbs.)
	(including consumables)
Options	Paper Feed Unit Type 204
	Paper Tray Type 204

1-2

25 December, 1998

PART NAMES AND FUNCTIONS

1.2 PART NAMES AND FUNCTIONS

1

5

2

4

3

G033V002.WMF

6

8

7

Overall Information

G033V004.WMF

1-3

PART NAMES AND FUNCTIONS			25 December, 1998
No.	Part	Function
1	Top Cover	Acts as an upper cover and a paper tray for printouts.
2	Paper Exit Unit	Feeds printouts to the top cover. Open when replacing the
		OPC belt cartridge.
3	Front Cover	The front enclosure; opened when replacing the toner
		cartridge or waste toner pack.
4	Main Switch	Turns the power on and off.
5	Operator Panel	Displays the status of the printer.
6	Interface	Install the controller here.
	Connector Box
7	AC Input Inlet	Connect the power supply cable here.
8	Back Cover (L)	Acts as the rear cover; opened when clearing an internal
		jam or doing maintenance work.

1-4

25 December, 1998

INTERNAL STRUCTURE

1.3	INTERNAL STRUCTURE
	9	10	11	1
	8
	7
	6			2
	5			3
	4
				G033V003.WMF

Overall Information

No.	Component Name	Function
1	Toner Cartridges	Holds the Y, M, C, and K toners for development. Each
		toner cartridge is independent.
2	Optical Unit	Generates a laser beam and scans it over the OPC belt.
3	Paper Cassette	Automatically feeds paper into the machine.
4	Paper Pick-up	Automatically feeds paper from the paper cassette.
	Roller
5	Transfer Drum	Receives color toner images from the OPC belt one at a
		time, in the order K, C, M, Y.
6	Transfer Roller	Transfers the combined K, C, M, Y toner image from the
		transfer drum to the paper.
7	Paper Discharger	Separates the paper from the transfer drum.
	(separation corona)
8	Transfer Unit	Transfers the combined K, C, M, Y toner image from the
		transfer drum to the paper.
9	Fusing Unit	Fuses the toner image to the paper.
10	Drum Cleaner	Removes waste toner adhering to the transfer drum.
11	Belt Cartridge	The laser forms an electrostatic latent image on the OPC
		belt, and this image is developed with toner.

1-5

OPERATOR PANEL

1.4 OPERATOR PANEL

		US	1
13			2
			3
12	Power	On Line	Data in
11			Reset
	Error		4
10	Me nu	Escape	5
			6
9	Media	# Enter	7
			8
		G033V000.WMF

1	LCD: 2 lines of 16 characters
2	On Line Indicator
3	Data In Indicator
4	Reset Key
5	Escape Key
6	Scroll Key (Up)
7	Enter Key
8	Scroll Key (Down)
9	Media Key
10	Menu Key
11	Error Indicator
12	On Line Key
13	Power Indicator

25 December, 1998

Europe

#

G033V001.WMF

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25 December 1998

OVERVIEW

2. DETAILED DESCRIPTIONS

2.1 OVERVIEW

2.1.1 MAIN UNITS

This color laser printer consists of five systems: Printing, Optics, Transfer, Paper

Transport, and Control.

1. Printing

The printing system consists of the following six units located around the OPC belt that form a toner image on the OPC belt.

∙Charge

∙Exposure

∙Development

∙First Transfer (from OPC belt to transfer drum)

∙Quenching

∙Belt Cleaning

2.Optics

The optics system consists of two units that form electrostatic latent images on the

OPC belt by scanning a laser beam across it.

∙Optics Unit

∙Polygon Mirror Motor

3.Transfer

The transfer system consists of three units that transfer the toner image to the copy paper.

∙Transfer Drum

∙Second Transfer (from transfer drum to paper)

∙Drum Cleaner

4.Paper Transport

The paper transport system consists of five units that pick up paper from the paper cassette, separate it from the transfer drum, and feed it out of the printer body after fusing the toner image onto it.

∙Paper Cassette

∙Transport Unit

∙Paper Discharger

∙Fusing Unit

∙Paper Exit

Detailed Descriptions

2-1

OVERVIEW

25 December 1998

G033M039.WMF

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25 December 1998

OVERVIEW

5. Control

The control system consists of four units that run the printer by processing the interface signals transmitted from the host and other systems.

∙Sequence Control

∙Laser Control

∙Fusing Temperature Control

∙Interface Control

2.1.2 BASIC COLOR PRINTING MECHANISM

1. Principle of Color Printing

Color printing is made through a subtractive process by combining the three primary colors, yellow, magenta, and cyan. The following illustration shows how cyan, magenta, and yellow toners can be combined to form other colors.

Detailed Descriptions

		Y: Yellow
	C	M: Magenta
		C: Cyan
		R: Red
		G: Green
B	G	B: Blue
	K	K: Black
M	R	Y

G033M040.WMF

2-3

OVERVIEW

2.Basic Color Printing Process

1)The printer contains yellow, magenta, cyan, and black toner cartridges.

25 December 1998

OPC Belt	Toner Cartridge
Transfer Drum

G033M047.WMF

2)The developed toner images are transferred to the transfer drum one at a time (a).

The transfer drum turns 4 times per image (if all colors are used). Black toner is transferred first, then cyan, magenta, and finally yellow.

3)The combined toner image formed on the transfer drum is transferred to the paper (b).

4)The fusing unit fuses the toner to the paper. (c)

Toner

G033M048.WMF

Transfer Drum

Paper G033M049.WMF

Red Cyan Green

Paper G033M050.WMF

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25 December 1998

OVERVIEW

2.1.3 OPC BELT STRUCTURE

Belt Cartridge

Toner Cartridge

OPC Belt

Transfer Drum

Optical Unit

Electrode

Photoconductor (OPC)

Aluminum

Insulator

G033M001.WMF

The OPC belt consists of a surface layer of organic photoconductor (OPC), an inner layer of insulation (PET), and an aluminum layer in between the two.

Detailed Descriptions

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PRINT SYSTEM AND TRANSFER SYSTEM

25 December 1998

2.2 PRINT SYSTEM AND TRANSFER SYSTEM

2.2.1 INTRODUCTION

The following illustration shows the basic steps of the printing system, with the OPC belt and transfer drum as the central components of the system.

G033M038.WMF

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25 December 1998

PRINT SYSTEM AND TRANSFER SYSTEM

2.2.2 PRINTER COMPONENTS

13 14

12

1

11

10

2

9

3

	8			G033M010.WMF
	7	6	5	4
No.	Name of Component			Process
1	Toner Cartridge			Development
2	Optical Unit			Exposure
3	Paper Cassette			Paper Feed
4	Charge Corona Unit			Charge
5	Cleaning Blade			Belt Cleaning
6	Belt Discharger (Quenching Lamp)			Belt Discharge
7	Dick-up Roller			Paper Pick-up
8	Transfer Drum			Image Transfer
9	Transfer Roller			Image Transfer
10	Paper Discharger			Paper Discharge
11	Paper Exit Unit			Paper Feed-out
12	Fusing Unit			Fusing
13	Drum Cleaner			Drum Cleaning
14	Belt Cartridge			Forming the Image

Detailed Descriptions

2-7

PRINT SYSTEM AND TRANSFER SYSTEM

25 December 1998

2.2.3 THE PRINTING SYSTEM

This section briefly describes the electrostatic imaging process for this printer.

1.Printing Process Overview

1)The CBV terminal of the high voltage unit charges the OPC belt to –CBV (V).

2)The CHV terminal of the high voltage unit applies a high negative voltage (-CHV) to the charge corona unit to generate the charge corona.

3)The DBV terminals (one for each color) of the high voltage unit power supply charge the development rollers to –DBV (V).

4)The transfer drum frame is grounded.

5)The THV(+) terminal of the high voltage unit applies a high positive voltage (+THV) to the transfer roller

G033M011.WMF

In the above diagram, blocks with a diagonal arrow through them indicate a power output that can be adjusted using an engine service mode. Potentiometers on the high voltage unit or laser diode drive board PCBs should not be touched.

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25 December 1998

PRINT SYSTEM AND TRANSFER SYSTEM

2.OPC Belt Potential Variations

1)The OPC belt is biased to -CBV(V). Then, during charging, the surface of the

OPC belt is evenly charged to -VO (V).

2)During exposure, the belt is discharged to -VR(V) when exposed to the laser beam, causing an electrostatic latent image to form on the OPC belt.

3)During development, the difference in potential between -VR(V) and -DBV(V) causes the negatively charged toner to move to the OPC belt, thereby forming a visible image. (Toner is attracted to the least negatively-charged surface, which is the exposed part of the OPC belt.)

4)During transfer, the negatively charged toner on the OPC belt moves to the transfer drum because the transfer drum potential (GND) is more positive than the OPC belt.

5)The OPC belt potential is discharged by the quenching lamp.

G033M012.WMF

1:Charging Process

2:Exposure Process

3:Development Process

4:Transfer Process

5:Cleaning (Quenching)

CBV: Power Supply for the OPC Belt Bias

CHV: Power Supply for Charging

DBV: Power Supply for Development Roller Bias -VR: Voltage on the exposed areas of the OPC Belt

Detailed Descriptions

2-9

PRINT SYSTEM AND TRANSFER SYSTEM 25 December 1998

2.2.4 PROCESS DETAILS

Charge

[C]

[B]

The charge corona unit evenly charges the

OPC belt.

(1) Charge Corona Unit Structure

1)

The charge corona unit consists of

[A]

the case [A], corona wire [B], and

grid [C].

2)

The charge corona unit charges the

OPC belt surface to a potential of

-VO (V).

3)

The zener diode keeps the grid at a

constant voltage ZD(V) to apply the

G033M051.WMF

charge to the belt evenly.

(2) Charging Process

1) The potential of the OPC belt surface before charging is -CBV(V).

2) The charge corona unit applies an even voltage of –VO to the OPC belt surface.

G033M041.WMF

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25 December 1998

PRINT SYSTEM AND TRANSFER SYSTEM

Exposure

During exposure, the OPC belt surface is exposed to the laser beam to form an electrostatic latent image.

1.Structure of the Optical Unit

1)The source of the laser beam is a semiconductor laser.

2)A lens and mirror scan the laser beam across the OPC belt to form the electrostatic latent image.

2.Exposure Process

1)After charging, the OPC belt surface has a potential of -VO (V).

2)The laser is scanned across the OPC belt perpendicular to the direction of motion.

3)The beam switches on then off at high speed in accordance with the image data.

4)The charge on the illuminated areas decreases to a potential of –VR (V). Unexposed areas remain at -VO (V)

5)As a result, an invisible electrostatic latent image forms on the OPC belt as shown below.

Detailed Descriptions

-VR

G033M013.WMF

Charge Exposure

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PRINT SYSTEM AND TRANSFER SYSTEM

25 December 1998

Development

During development, toner causes the electrostatic latent image on the OPC belt to become visible.

1.Toner Cartridges

1)There are four toner cartridges from top to bottom in this order: black, yellow, magenta and cyan. It is not possible to install them in the wrong order.

NOTE: This is not the same as the order of development (which is black, cyan, magenta, yellow).

2) Each cartridge contains a single toner color [A].

2.Development Process

1) Toner [B] from the toner cartridge [D]		[E]
adheres to the development roller	[C]	[D]
[C].
Development occurs when this roller
comes in contact with the OPC belt
[E] surface.
[B]
		[A]

G033M014.WMF

2) The development roller is biased to	[C]
						(-CBV) + (-DBV)
the potential -DBV (V).

[B]

[E]

DBV

CBV

G033M015.WMF

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25 December 1998 PRINT SYSTEM AND TRANSFER SYSTEM

3) During development, a visible toner image is formed on the OPC belt. Toner is attracted to the least negatively-charged surface, which is the exposed part of the OPC belt.

	4) On the other hand, unexposed areas are not developed, because these
			s
	have a higher negative charge than the toner, so they repel the toner.	Detailed	secription
	The diagram shows the positions of the four color development units in
	relation to the belt. In the diagram, the magenta image is being developed.		D
	If there are only two colors used in the image data, the other two
	development cycles will be skipped.

Toner (M)

Exposure

G033M016.WMF

Development

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PRINT SYSTEM AND TRANSFER SYSTEM

25 December 1998

Toner Cartridge Positioning Mechanism

[A]

[D]

[A]

[C]

[A]

[B]

[A]

G033M056.WMF

When the printer is idle, none of the toner cartridges contacts the OPC belt. During printing, the machine moves the toner cartridges into contact with the belt one at a time, in the order K, C, M, Y.

There are two toner cartridge drive mechanisms. One is for the black and yellow cartridges (the uppermost two cartridges), and the other drives the cyan and magenta cartridges.

In each mechanism, cams [A] driven by a spring clutch [B] and solenoid [C] mechanism push the toner cartridges into position. A sensor (the development sensor) [D] detects when the mechanism for the pair of cartridges is at home position.

Before the start of printing, the cams are pointing vertically (position 1 for KY and position 3 for CM in the diagram; note that in the diagram, the view of the mechanism has been rotated 90°). At this time, the actuator is inside the development sensor, which informs the CPU that the mechanism is in home position.

To move the black toner cartridge into contact with the belt, the development solenoid (K,Y) releases the pawl on the spring clutch, which turns 180°, and this turns the cam shaft 90° (to position 2 for KY in the diagram). When the cam shaft rotates, the cam pushes the black toner cartridge into contact with the belt.

After the black development cycle, the solenoid turns off, which allows the cam shaft to turn another 90° (to position 3 for KY in the diagram). The black toner

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25 December 1998

PRINT SYSTEM AND TRANSFER SYSTEM

cartridge is now pushed away from the belt by a spring. During this period, the solenoid for cyan and magenta remains off.

At about the same time, the solenoid and clutch mechanism for cyan and magenta moves the cyan cartridge into contact with the belt. To do this, the solenoid for cyan and magenta turns on. The cams turn 90° (to position 4 for CM in the diagram). This pushes the cyan cartridge against the belt. After the cyan cycle, the solenoid turns off, and the cam turns 90° again, to position 1 in the diagram.

Next, the solenoid and clutch mechanism for cyan and magenta moves the magenta cartridge into contact with the belt. The sequence of events is similar to that for the black toner cartridge described above. After this cycle, the cyan/magenta mechanism is back in home position. During this period, the solenoid for black and yellow remains off.

Then the yellow development cycle begins, using the black/yellow mechanism again. After this cycle, the black/yellow mechanism is back in home position as well.

Detailed Descriptions

Position of each cam in the diagram during development

	HP	Dev. K	→	Dev. C	→	Dev. M	→	Dev. Y	HP
KY	1	2	3	3	3	3	3	4	1
CM	3	3	3	4	1	2	3	3	3

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PRINT SYSTEM AND TRANSFER SYSTEM

25 December 1998

Toner End Sensor

[B]

[A]

G033M014.WMF

There is a toner end sensor for each cartridge. The components of the sensor are located on the left and right sides of the machine (there is a photodiode at one side of the cartridge and a phototransistor at the other side). There are small windows

[A] to allow the light from the photodiode to pass through the cartridge. When the solenoid and clutch mechanism pushes the cartridge against the belt, drive from the development motor is transmitted to the toner cartridge, then agitator [B] mixes the toner inside the cartridge. At this time, if the light path inside the cartridge remains blocked, the machine detects that there is sufficient toner in that cartridge.

If the light path becomes unblocked, toner near end is detected.

After near-end is detected, the machine allows up to 500 images (for the C, M, and Y cartridges) or up to 300 images (for the K cartridge) to be made until the toner end condition is reached. There are separate counters for each color. When one of the cartridges reaches a toner end condition, the machine prevents further printing.

If the front cover is opened for 15 seconds, any toner near-end or toner end conditions are cleared.

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25 December 1998

PRINT SYSTEM AND TRANSFER SYSTEM

First Transfer (From Belt to Drum)

During the first transfer process, toner images on the OPC belt are transferred to the transfer drum one color at a time.

The Transfer Drum

[A]

[B]

[C]

G033M052.WMF

Detailed Descriptions

1)The transfer drum [A] has an aluminum [B] base and a rubber coating [C].

2)The transfer drum is driven by contact with the OPC belt. The rotation speeds and circumferences of the drum and belt are the same, so the leading edge of the toner image always arrives at the same place on the drum. The CPU uses the drum encoder to monitor the drum rotation, in case any slippage occurs. (SC 71 is generated if an error occurs.)

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PRINT SYSTEM AND TRANSFER SYSTEM

25 December 1998

First Transfer Process

Residual Charge

OPC Belt

Residual Toner

Belt Cleaning (Blade)

Drum
Transferring	G033M018.WMF

Belt Discharging

(Quenching Lamp)

1)After the OPC belt passes the development mechanism, it comes in contact with the transfer drum. The transfer drum and belt rotations are synchronized so that the leading edge of the toner image on the belt always arrives at the same place on the drum.

2)The OPC belt has a negative voltage (the magnitude depends on whether it is an exposed or unexposed area of the belt). The potential of the transfer drum is nearly GND (Ground).

3)The difference in potential between the OPC belt and the transfer drum causes the negatively charged toner on the OPC belt to move to the transfer drum.

4)Each toner color moves from the OPC belt onto the transfer drum, and a fullcolor toner image builds up with each rotation of the transfer drum.

5)After all four colors have been transferred to the drum, the toner image transfers to the paper.

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25 December 1998

PRINT SYSTEM AND TRANSFER SYSTEM

Belt Discharging (Quenching Lamp)

During belt discharge (after drum transfer), the quenching lamp illuminates the

OPC belt to discharge the residual charge before cleaning the belt.

1.Quenching Lamp

1)The quenching lamp is an LED array containing 24 light emitting diodes (LEDs).

Discharge Process

Detailed Descriptions

		Belt
		Cleaning
	Drum	(Blade)
		G033M020.WMF
	Transferring

Belt Discharging (Quenching Lamp)

1)After the toner image has transferred to the transfer drum, a residual charge still remains on the OPC belt.

2)The quenching lamp discharges the OPC belt before belt cleaning. This makes it easier for the belt cleaner to remove remaining toner particles from the belt, and prepares the belt for the next development cycle.

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PRINT SYSTEM AND TRANSFER SYSTEM

25 December 1998

Belt Cleaning

During belt cleaning, residual toner adhering to the OPC belt surface is removed.

1.Cleaning Blade

1) The belt cleaning blade is in the belt cartridge.

2.Belt Cleaning

		Belt Cleaning
		(Blade)
	Drum	G033M020.WMF
	Transferring
		Discharging
		(Quenching Lamp)

1)A small amount of toner remains on the OPC belt because it did not transfer during the drum transfer process.

2)The edge of the blade scrapes the residual toner off the OPC belt.

3)The waste toner feeder feeds the toner to the waste toner bottle.

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