Xerox DocuMate 252 User manual

Sheetfed Scanner
Service Manual
Version 1.0

Sheetfed Scanner
Contents
1. INTRODUCTION...........................................................................................................................1-1
1.1 GENERAL NOTES FOR SERVICING..............................................................................................1-1
1.2 GENERAL DESCRIPTION ...........................................................................................................1-2
1.3 BASIC SPECIFICATIONS ...........................................................................................................1-2
2. UNPACKING, INSTALLATION, AND TRANSPORTATION..............................................2-1
2.1 PRECAUTIONS OF INSTALLATION..............................................................................................2-1
2.2 UNPACKING PROCEDURE..........................................................................................................2-1
2.3 INSTALLATION .........................................................................................................................2-3
2.3.1 Installing the ADF Paper Tray............................................................................2-3
2.3.2 Installing the ADF Output Paper Tray ..............................................................2-4
2.3.3 Connecting the Cables.........................................................................................2-5
2.3.4 Turning on the Power ..........................................................................................2-5
2.4 PLACING THE ORIGINAL ...........................................................................................................2-6
3. THEORY OF OPERATION..........................................................................................................3-1
3.1 INTRODUCTION........................................................................................................................3-1
3.2 MAIN CONTROL UNIT................................................................................................................3-2
3.2.1 System diagram....................................................................................................3-2
3.2.2 Main control circuit...............................................................................................3-3
3.2.3 Video circuit: .........................................................................................................3-4
3.2.4 LED and Push Button Module Circuit................................................................3-6
3.2.5 Sensor input ..........................................................................................................3-7
3.2.6 Sub power supply circuit.....................................................................................3-8
3.2.7 Power supply .........................................................................................................3-9
4. PROBLEM SOLVING....................................................................................................................4-1
4.1 DIAGNOSTICS..........................................................................................................................4-1
4.1.1 Online diagnostics ................................................................................................4-1
4.1.2 Offline diagnostics ................................................................................................4-2
4.1.3 Diagnostic flowcharts...........................................................................................4-3
4.2 TROUBLESHOOTING .................................................................................................................4-6
4.2.1 Flowcharts ..............................................................................................................4-6
4.2.2 Tables......................................................................................................................4-9
5. DISASSEMBLY..............................................................................................................................5-1
5.1 SERVICE TOOL.........................................................................................................................5-1
5.2 CLEANING THE ADF ................................................................................................................5-2
5.3 CLEANING THE CALIBRATION AREA..........................................................................................5-3
5.4 PROCEDURE FOR DISASSEMBLY AND REASSEMBLY ....................................................................5-4
5.4.1 Notes on disassembly..........................................................................................5-4
5.4.2 Removing the Upper Housing ............................................................................5-5
5.4.3 Removing the Upper Optical Assembly............................................................5-7
5.4.4 Removing the Upper Optical Chassis ...............................................................5-9
5.4.5 Removing the Lamp in Upper Optical Assembly..........................................5-10
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Service Manual
5.4.6 Removing the ADF Pad......................................................................................5-11
5.4.7 Removing the Main Control Board..................................................................5-12
5.4.8 Removing the Motor in Lower Optical Assembly .........................................5-14
5.4.9 Removing the Inverter in the Lower Optical Assembly..............................5-15
5.4.10 Removing the Lower Optical Chassis..........................................................5-16
6. PARTS..............................................................................................................................................6-1
6.1 SPARE PART DIAGRAM..............................................................................................................6-1
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Service Manual
1. INTRODUCTION
1.1 General Notes for Servicing
1.2 General Description
This manual is intended to be used by the maintenance engineers. It describes areas to be
maintained, the detailed installation, the disassembly of optional ADF, and the component
replacement procedures as well as the main trouble shooting guides.
Please take your time to read this manual thoroughly to obtain comprehensive knowledge
about the scanner before serving the unit.
1.1 General notes for servicing
(1) Before trying to disassemble the scanner, make sure the power supply cord of
theAV220 is disconnected from the power outlet. Under any circumstance, do not
remove or install the connectors on the scanner with the power supply turned ON.
(2) Use caution not to drop small parts or screws inside the unit when disassembling and
reassembling. If left inside, they might cause the malfunction of the unit.
(3) Do not pull the connector cable when disconnecting it. Hold the connector.
(4) When carrying the scanning head unit, put it in an anti-static bag.
(5) Keep the document table glass surface always clean. If contaminated, use a dry
clean cloth for cleaning.
(6) Use caution not to injure your fingers or hands when disassembling or reassembling
the unit.
1-1

Sheetfed Scanner
1.2 General Description
The scanner which features small footprint and fast scan rate is the perfect companion at
your desktop. The build-in automatic document feeder allows 50 sheets of documents to be
scanned continuously at one time and achieves fast scan rate of 25 pages per minute in
simplex mode and 50 images per minute in duplex mode.
1.3 Basic Specifications
Type: Sheetfed scanner, duplex
Optical Resolution: 600 dpi
Color Depth: 48-bit Color (input)
24-bit Color (output) single pass color (R, G, B)
Image Type:
256 shades of gray scale
64 shades of gray for halftones
Line art (binary)
Error diffusion
8-bit Color
24-bit Color
ADF Scan Speed:
(NONE Channel at 200dpi
B&W A4 size)
25 pages per minute (simplex mode)
50 images per minute (duplex mode)
Scan Area:
ADF: minimum: 3.5” x 2” (88 x 50 mm) ADF: maximum: 8.5”x 14” (215 x 355 mm)
Paper Size:
ADF Max.: 8.5” x 14” (Legal) ADF single page min.: 3.5” x 2”
ADF duplex multipage min.: 3.5” x 3.0”
Paper Thickness: 16 – 28 lbs/0.002” ~ 0.006”
Paper Input (ADF): up to 50 sheets
Physical Dimension:
HxWxD 6.37 x 13,2 x 6.5 inches (without tray)
(162.3 x 337.2 x 167.8 mm)
Weight: 4.3 kg
Interface: USB 2.0
Power Source: Input: 100~240V, AC, 50/60 Hz
Output: 24V, DC, 2.0A
Power Consumption: ≤30 Watts
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Service Manual
2. UNPACKING, INSTALLATION, AND
TRANSPORTATION
2.1 Precautions of Installation
2.2 Unpacking Procedure
2.3 Installation
2.4 Placing the Original
2.5 Transportation
2.1 Precautions of Installation
Pay attention to the following matters before unpacking and installation.
•Do not install in a place where vibration may occur.
•Keep the scanner out of direct sunlight. Do not install near a heat source.
•Do not place the scanner around materials which shut off the circulation of air.
•Do not install in a humid or dusty place.
•Use care not to scratch the glass surface of the scanner or the document holding
pad with a clip or staple.
•Do not use the wall socket with connecting devices which may generate noise, for
example, air-conditioner, etc.
•Use a suitable AC power source.
•Place the scanner on a level surface.
2.2 Unpacking Procedure
Unpack the scanner according to the following procedure.
•Remove the packing material.
•Remove the scanner from the shipping container.
•Remove the scanner from the PVC bag.
•Check the items by referring to Figure 2.1.
•For any missing items, please contact your nearest dealer or distributor.
Note: Keep all the packing material in case you may need to return the scanner.
2-1

2
3
1
6
4 5
1. Main Unit
2. Input Paper Tray
3. Output Paper Tray
4. USB Cable
5. Power Adapter
6. Power Cord
Figure 2.1 Package Contents
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Service Manual
2.3 Installation
2.3.1 Installing the ADF Paper Tray
1. Attach the ADF Paper Tray to the clip joint of the scanner as indicated below. When
properly insert, you will hear a snap-in sound.
ADF Input
Paper Tray
Scanner
Clip Joint
Figure 2.2 Installing the ADF Paper Tray
2-3

2.3.2 Installing the ADF Output Paper Tray
1. Hold the Output paper tray some 30 degrees as shown in below.
2. Insert the right protrusion of the Output Paper Tray into the hole on the front of the
scanner.
3. Insert the left protrusion of the Output Paper Tray slightly into the hole on the front of
the scanner.
Scanner
Output
Paper Tray
Hole
Output
Paper Tray
Protrusion
Figure 2.3 Installing the Output Paper Tray
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Service Manual
2.3.3 Connecting the Cables
Make sure the power of scanner is off.
2.3.3.1 Connecting to Power
Plug the small end of the power adaptor into the power jack of your scanner. Insert the
other end to an appropriate power outlet.
Power Cable
Figure 2.4 Installing the Power Cable
2.3.4 Turning on the Power
After the power cable and the USB cable have all connected, press the power switch to
the “I” position to turn on the scanner. To turn off the scanner, please press the power
switch to the “O” position.
Power Switch
Figure 2.5 Turn on the scanner
2-5

2.4 Placing the original
Document feeding
Place your document with the text face down on the ADF Input Paper Tray. Align the
two sides of the document with the slide guides. Please note that the ADF Input Paper
Tray can hold up to 50-page document at a time.
Your
Document
(Face
Do n)
Paper Slider
Figure 2.6 Place the document
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Service Manual
3. THEORY OF OPERATION
3.1 Introduction
3.2 Main Control Unit
3.1 Introduction
Mai
Boar 10010
Cold
Len CCD
Analogu
Signa Digital
Signa
Fluorescent Hos
Reflecte
Ray Main
Board 10010
Cold
Len CCD
A
nalo
g
ue
Signal Digital
Signal
Fluorescent Lamp
Reflected
Ray USB 2.0
Controlle
r
Host
Figure 3.1 Theory of Operation
The reflected rays of your original as shown in the above Figure 3.1 pass through the lens
and create an image on the CCD (Charged Coupled Device). Then, according to the
different light intensity perceived by the CCD, the CCD will transfer these data into a series
of analog signals to the main board, where the signals are turned into digital signals.
These digital signals flow to the USB 2.0 Controller to transfer to a host computer.
3-1

3.2 Main control unit
3.2.1 System diagram
Figure 3.2 System block diagram
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Service Manual
3.2.2 Main control circuit
This scanner is controlled by the 80C32. The 80C32 is configured with a 64-KB
external ROM program area, a 256-BYTE internal RAM work area, a 64-KB external
RAM work area, 2 timer / counters, 4 I/O ports, 2 external interrupts, and 2 internal
interrupts for 2 internal timer / counters.
Address Maps:
•ROM program area:
•Internal RAM working area:
yExternal SRAM working area:
0000 64KB Program
FFFF
00 256-byte
Internal Registers
FF
0000 64 KB
External Program
FFFF
3-3

3.2.3 Video circuit:
The video circuit of the scanner includes: 1. CCD driving circuit, 2. CCD signal
processing circuit.
1. CCD Driving Circuit
The CCD driving circuit is used to generate correct signals to the CCD, so that the
CCD may generate the correct image data.
Signals for CCD:
Pin Assignment for CCD cable
Pin
No.
Name Function
1 AG Analog Ground
2 VOR CCD Red Channel Output Signal
3 AG Analog Ground
4 VOG CCD Green Channel Output Signal
5 AG Analog Ground
6 VOB CCD Blue Channel Output Signal
7 AG Analog Ground
8 12VDC CCD Power Supply
9 SH CCD RGB Channel Shift Gate
10 PHI1 CCD Clock Phase
11 DG Digital Ground
12 PHI2 CCD Clock Phase
13 DG Digital Ground
14 RS CCD Reset Gate
15 DG Digital Ground
16 CP Clamp Gate
17 VCC Digital 5V Power Supply
18 SW Changeover Switch (color and
B/W)
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Service Manual
2. CCD signal processing circuit
CDS
CCD Signal Processor
CDS
CDS
PGA
PGA
PGA
CCD MUX ADC
R
G
B
Dout
The CCD signal processor includes all the necessary circuitry to perform three-
channel conditioning and sampling. The signal chain consists of three-channel
correlated double sampling (CDS) and programmable gain adjustment of the CCD
output (PGA) is a 16 bit analog to digital connector (ADC) quantizes the analog
signal.
3-5

3.2.4 LED and Push Button Module Circuit
The circuit for the LED and Push Button modules showes the function of the entire
scanner including the Error LED (Red), the Ready LED (Green) and the Push Button.
.
Pin assignment of LED module
Pin No. Name Function
1 Ground Ground
2 Ground Ground
3 Button Scan
4 Button Cancel
5 Button Function select
6 LED G Ready status indicator
7 LED R Seven segment display
8 Seven 1 Seven segment display
9 Seven 2 Seven segment display
10 Seven 3 Seven segment display
11 Seven 4 Seven segment display
Seven 5
12 Seven segment display
13 Seven 6 Seven segment display
14 Seven 7 Seven segment display
Seven 8 Seven segment display
15
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Service Manual
3.2.5 Sensor input
A. Photo_Sensor
The sensor input includes paper in/out sensor.
Paper In/Out sensor
The paper position is detected by photo sensor. The photo transistor transmission
to the photo sensor receiver circuit is shown below.
Out
Figure 3.3 Paper in/out sensor
The paper in/out sensor is detected when the paper passes between the LED and the
photo transistor.
B. IR-Sensor
+5V +5
V
Figure 3.4 IR_Sensor
+
_
-
(OP)
DAC
Out
3-7

3.2.6 Sub power supply circuit
The sub power supply circuit is provided for the internal analog circuit. Input is
24V and output is Vcc and +5Va. The circuit configuration is shown below:
+24Vdc Vcc
Switching
+12V +5Va
+24Vdc +12V
Vcc +3.3V
The sub power supply is used for: A/D, and logic circuits.
Re
g
ulato
r
Linear
Re
g
ulato
r
Linear
Re
g
ulato
r
Linear
r
Re
g
ulato
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Service Manual
3.2.7 Power supply
In this system, there is only one type of power supply. Please see Table 3.1 for
details.
Table 3.1 The Power Adapter
Type
Characteristic Wall-mount
Input voltage range 100-240V
Input current (at the
rated input/output)
2A type or less
Input frequency 50-60Hz
Max. in-rush
current(@full load,
cold start)
45A
Output voltage +24Vdc
Min. load current 0.0A
Max. load current 2A
Total power (at full
load)
30W
3-9