Xerox DWC165c, DFC165 Service Manual

XEROX
Document FaxCentre 165
and
Document WorkCentre 165c
SERVICE MANUAL
Part Number : 602E48370

PREFACE

This manual is intended for service engineers responsible for installing, servicing and repairing the facsimile machines described herein. The manual consists of thirteen chapters which describe:
Chapter 1: the General Features and Technical Specifications
Chapter 2: the facsimile machine's Internal and external structure
Chapter 3: the Installation and setup procedures
Chapter 4: how to set the Software Parameters
Chapter 5: the Diagnostic and testing procedures
Chapter 6: the Settings and adjustments
Chapter 7: the Maintenance and replacement procedures
Chapter 8: the Optional devices
Chapter 9: the Installation of the LinkFax 8 module in Windows 95
environment
Chapter 10: the User Guide of the LinkFax 8 module in Windows 95
environment
Chapter 11: the Installation of the LinkFax 8 module in Windows 3.1x
environment
Chapter 12: the User Guide of the LinkFax 8 module in Windows 3.1x
environment
Chapter 13: the Spares List
FIRST EDITION: April 1998
REFERENCES: User Manual

CONTENTS

1. INTRODUCTION.................................................1-1
1.1 MAIN FEATURES.....................................................................1-1
1.2 TECHNICAL SPECIFICATIONS...................................................1-2
1.3 QUICK REFERENCE GUIDE.........................................................1-5
1.3.1 Sending a Fax......................................................................................1-5
1.3.2 Receiving a Fax....................................................................................1-5
1.3.3 Using the Facsimile Machine as a Photocopier ........................................1-5
2. GENERAL DESCRIPTION ....................................2-1
2.1 EXTERNAL PARTS...................................................................2-1
2.1.1 Console...............................................................................................2-2
2.1.2 Functions of the console keys ...............................................................2-3
2.2 ELECTROMECHANICAL PARTS.................................................2-6
2.2.1 Motors ................................................................................................2-6
2.2.2 Sensors ...............................................................................................2-7
2.2.3 Speaker...............................................................................................2-8
2.3 ELECTRONIC PARTS................................................................2-9
2.3.1 General Block Diagram .......................................................................2-10
2.3.2 Block Diagram of the Motherboard......................................................2-11
2.3.3 Block Diagram of the Network Control Unit Board ................................2-14
2.3.4 Block Diagram of the Power Supply Board ...........................................2-15
2.3.6 Printer Unit .......................................................................................2-17
3. INSTALLATION AND INITIALIZATION
PROCEDURES.....................................................3-1
3.1 PRELIMINARY OPERATIONS....................................................3-1
3.1.1 Unpacking the Facsimile Machine ..........................................................3-1
3.1.2 Connecting to the Telephone Line .........................................................3-2
3.1.3 Connecting the Power Cord ..................................................................3-4
3.1.4 Installing the Print Head.......................................................................3-4
3.1.5 Inserting the Output Trays ....................................................................3-9
3.1.6 Loading Paper ...................................................................................3-10
3.1.7 Feeding special papers manually on the LinkFax model .........................3-10
XEROX DFC165 & DWC165c Service Manual v
3.2 INSTALLING AND SETTING UP THE MACHINE...........................3-12
3.2.1 Organization of the Installation and Setup Parameters ..........................3-12
3.2.2 Setting the Country Parameters ...........................................................3-15
3.2.3 Storing the User's Number and Name ..................................................3-16
3.2.4 Setting Up the Telephone Line ............................................................3-17
3.2.5 Completing Installation ......................................................................3-19
3.2.6 Resetting the Fax Machine ..................................................................3-19
4. SERVICE SWITCHES...........................................4-1
4.1 SERVICE SWITCH TABLES.......................................................4-3
5. DIAGNOSTICS....................................................5-1
5.1 SELF-DIAGNOSTICS ................................................................5-1
5.1.1 Description of the Self-Diagnostic Program ............................................5-2
5.2 ERROR CODES........................................................................5-3
5.2.1 Meaning of Protocol Signal Codes.........................................................5-4
5.2.2 Meaning of Error Codes ........................................................................5-6
5.2.3 Printing the Communication Protocol ....................................................5-9
5.2.4 Printing the Counters .........................................................................5-11
5.3 REPORTS .............................................................................5-12
5.3.1 Transmission Report (LAST TX REPORT) ..............................................5-12
5.3.2 Broadcast Transmission Report (LAST BROAD. REP.) .............................5-14
5.3.3 Activity Report (ACTIVITY REPORT) ....................................................5-14
5.3.4 Power Failure Report ..........................................................................5-15
5.4 REMOTE DIAGNOSTICS..........................................................5-16
5.4.1 Enabling the Facsimile Machine as a "Slave Station" .............................5-16
6. SYSTEM TEST AND ADJUSTMENTS.....................6-1
6.1 SYSTEM TEST .........................................................................6-1
6.1.1 ALIGNMENT TEST................................................................................6-2
6.1.2 NOZZLES TEST ...................................................................................6-4
6.1.3 CLEANING...........................................................................................6-6
6.1.4 PRINT CHART ......................................................................................6-7
6.1.5 ASF TEST ............................................................................................6-9
6.1.6 ADF TEST ...........................................................................................6-9
6.1.7 LOAD DEFAULT .................................................................................6-10
vi XEROX DFC165 & DWC165c Service Manual
6.1.8 SCANNER SHADING ...........................................................................6-10
6.1.9 CARRIAGE TEST ................................................................................6-11
6.2 CHECKS AND ADJUSTMENTS..................................................6-12
6.2.1 Checking the Direct Voltages ..............................................................6-12
6.3 ADJUSTING THE CCD.............................................................6-13
6.3.1 Preparing for the CCD Adjustment.......................................................6-13
6.3.2 Checking the Alignment of the CCD Board ...........................................6-14
6.3.3 Checking the Lens Focus ....................................................................6-16
6.3.4 Checking that the Document and the CCD are centred ..........................6-17
7. MAINTENANCE AND REPLACEMENT
PROCEDURES.....................................................7-1
7.1 MAINTENANCE ........................................................................7-1
7.1.1 OUT OF INK Message ...........................................................................7-1
7.1.2 Replacing the rechargeable Ink Cartridge ...............................................7-2
7.1.3 Replacing the Print Head ......................................................................7-3
7.1.4 Cleaning the Print Head ........................................................................7-3
7.1.5 Cleaning the Electrical Contacts ............................................................7-4
7.1.6 Cleaning the Print Head Cleaning Pad ....................................................7-5
7.1.7 Cleaning the Optical Unit ..................................................................... 7-6
7.2 DISASSEMBLY AND REPLACEMENT PROCEDURES...................7-10
7.2.1 Wirings .............................................................................................7-10
7.2.2 Removing the Casing .........................................................................7-12
7.2.3 Removing the Power Supply/NCU Assembly ........................................7-13
7.2.4 Removing the Power Supply and NCU Boards ......................................7-15
7.2.5 Removing the Motherboard ................................................................7-16
7.2.6 Removing the Console .......................................................................7-18
7.2.7 Removing the Console Board ..............................................................7-19
7.2.8 Removing the Display .........................................................................7-19
7.2.9 Removing the Scanner Unit ................................................................7-20
7.2.10 Removing the CCD Board ...................................................................7-21
7.2.11 Removing the LED Array ....................................................................7-21
7.2.12 Removing the Printer Unit ..................................................................7-22
7.2.13 Removing the Carriage, Paper and Ink Drain Motors .............................7-23
7.2.14 Removing the Scanner Motor ..............................................................7-24
7.2.15 Removing the Print Carriage ...............................................................7-24
8. OPTIONAL DEVICES ...........................................8-1
8.1 SETTING UP A BACK TO BACK CONNECTION.............................. 8-2
XEROX DFC165 & DWC165c Service Manual vii
8.2 CONNECTING A TELEPHONE ANSWERING DEVICE.......................8-2
8.3 CONNECTING A TELEPHONE EXTENSION.....................................8-3
8.4 HANDSET ...............................................................................8-4
9. INSTALLATION OF THE LINKFAX 8 MODULE
IN WINDOWS 95 ENVIRONMENT.......................9-1
10. USER GUIDE OF THE LINKFAX 8 MODULE
IN WINDOWS 95 ENVIRONMENT.....................10-1
11. INSTALLATION OF THE LINKFAX 8 MODULE
IN WINDOWS 3.1X ENVIRONMENT..................11-1
12. USER GUIDE OF THE LINKFAX 8 MODULE
IN WINDOWS 3.1X ENVIRONMENT..................12-1
13. SPARE PARTS LISTINGS.................................... 13-1
viii XEROX DFC165 & DWC165c Service Manual

1. INTRODUCTION

The two models referred to in this manual are desktop facsimile machines with a bubble ink jet printing system which complies with the ITU-TS G3 standard for document transmission and reception.
The most suitable factor to distinguish between the two models, similar in appear­ance, is the possibility of using a monochrome print head only or both monochrome and colour print heads.
The colour model, once connected to a PC equipped with the LinkFax 8 software communication module, can be transformed into a multifunctional product able to perform both printer and scanner functions in addition to the facsimile traditional features. The colour print head must be used only for printing purposes. All standard facsimile functions require a monochrome print head. In this manual, the two models are referred to as follows:
standard model (monochrome) LinkFax model (colour)

1.1 MAIN FEATURES

Bubble ink jet printing
The facsimile machine prints on plain paper (standard model) or special paper (LinkFax model) in various formats (A4, Letter, Legal).
Memory capacity
The facsimile machine has a memory which enables operations such as One­touch Dialling, Speed Code Dialling, Broadcasting Transmission, Delayed Trans­mission and Substitute Reception, as well as the storage of parameters, data and
documents. This memory is powered by a backup battery in the event of a power failure.
Half tones
In the scanning of documents, a scale of 64 half tones can be used for a higher
XEROX DFC165 & DWC165c Service Manual
1-1
quality reproduction of photographs and pictures.
Automatic document feeder (ADF)
This device enables up to 10 sheets of A4, A5, Letter US or Legal paper, with a maximum thickness of 0.1 mm/sheet, to be fed in automatically.
Telephone answering device (TAD)
The model without a built-an TAD can be connected to an external one.

1.2 TECHNICAL SPECIFICATIONS

Physical characteristics
Type Dimensions (L, D, H) Weight
Operator console
Display Keypad
Power supply
Operating range Average consumption
Desktop transceiver
324 x 325 (+ 1701 + 1182) x 230 (+ 602)mm
6.3 kg
2 lines of 16 characters
- 11 function keys of which 7 are dual function
- 12 dual-function keys for normal dialling and user name setting
- 10 one-touch dialling keys
- 1 error LED
220-240V, 50/60Hz 11W (in standby); less than 30W (copying)
Communication characteristics
Type of connection
Compatibility Type of modulation Transmission speed
Public telephone network (PSTN) or private branch ex­change (PBX)
ITU-TS G3 standard CCITT V29 / V27ter 2400 / 4800 / 7200 / 9600 bps
(1) with the document output tray (2) with extension >>
1-2
XEROX DFC165 & DWC165c Service Manual
Type of communication
Half duplex Coding methods Transmission time
Scanner
Scanning system Resolution
Document size (width x length)
Actual scanning area
Automatic document feeder (ADF)
MH, MR
About 15 s for ITU-TS test sheet n°1 (Slerexe Letter)
at 9600 bps in standard resolution
CCD (Charge Coupled Device)
Vertical: 3.85 (standard) / 7.7 (fine) lines/mm
Horizontal: 8 dots/mm
From 148 x 105 mm (minimum length) to 216 x 2000 mm
(maximum length)
Horizontal: 210 mm
Vertical: within 4 mm of the edge of the document
Capacity: 10 sheets of A4 / Letter US / Legal format
(thickness max 0.1 mm/sheet)
Thickness of sheets: min 0.06 mm, max 0.12 mm Half tones
Contrast
Printer
Printing method
Printing speed Automatic sheet feeder
Print resolution Actual printing area
The facsimile machine can emphasize the contrast of text
areas and reproduce pictures with 64 half tones.
Three levels are handled: dark, normal and light
Bubble ink jet on plain paper (standard model) or special
paper (LinkFax model)
ITU-TS test sheet n°1 (Slerexe Letter) / about 40 s
Capacity: 80 sheets of A4 / Letter US / Legal format
(weight 70-90g/m2) 200 x 100 / 200 dpi 208 x 290 (A4) / 273 (Letter US) / 349 (Legal) mm
Memory
Capacity
XEROX DFC165 & DWC165c Service Manual
512 kbytes (about 360 kbytes as user memory) pow­ered by a backup battery
>>
1-3
Dialling
Dialling mode Dialling on facsimile machine
Redialling One-touch dialling Speed code dialling
Delayed transmission Broadcasting transmission
Other features
Automatic reception
Pulse and tone The number can be dialled directly on the facsimile machine's
keypad A number can be redialled in automatic or manual mode There are 10 one-touch dialling keys There are 32 memory locations, each of which may be as-
signed a facsimile ID A document can be sent automatically at a preset time A document may be sent automatically to several correspond-
ents (max 10).
The facsimile machine can be set to receive a document automatically
Polling
Reports
Environmental conditions
Temperature
Relative humidity
Polling reception and free polling trasmission features are available
Various kinds of reports may be printed (transmission, activity, etc.)
Operating: from 5°C to 35°C Storage:from 0°C to +45°C Transport:from -15°C to +45°C
Operating: from 15% to 85 % (without condensation) Storage: from 15% to 85 % (without condensation) Transport: from 5% to 95 % (without condensation)
1-4
XEROX DFC165 & DWC165c Service Manual

1.3 QUICK REFERENCE GUIDE

1.3.1 Sending a Fax

1. Insert the document into the automatic document feeder.
2. Press the HOOK key and dial the correspondent's number on the numeric keypad.
3. Wait for the answering tone from the correspond­ent's machine and then press START.

1.3.2 Receiving a Fax

S. DIAL
î
HOOK
ê
RX MODE
LAST TX
REDIAL
RESOL.
- VOLUME +
EXT.
PAUSE 2.TONE
í
START
CONTR.
HOLD
ERROR
STOP
1. The facsimile machine is normally set for automatic reception: the message AUTOMATIC RX is dis-
played.
S. DIAL
2. If you want to receive a fax in manual mode, press the RX MODE key: the message MANUAL RX will be displayed.

1.3.3 Using the Facsimile Machine as a Photocopier

1. Insert the document into the automatic document feeder.
S. DIAL
2. Type on the numeric keypad the number of copies to start (max. 50 copies)
3. Press the START key.
HOOK
ê
RX MODE
LAST TX
REDIAL
RX MODE
LAST TX
REDIAL
RESOL.
- VOLUME +
EXT.
PAUSE 2.TONE
START
RESOL.
- VOLUME +
EXT.
PAUSE 2.TONE
ê
START
CONTR.
HOLD
STOPHOOK
CONTR.
HOLD
STOP
ERROR
ERROR
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1-5
.

2. GENERAL DESCRIPTION

2.1 EXTERNAL PARTS

The figure shows the main external parts, of the facsimile machine.
Automatic sheet feeder
(ASF) cover
Automatic Document Feeder (ADF) guides
Console
Document
tray
Received and copied
document tray
TAD socket
TEL2
XEROX DFC165 & DWC 165c Service Manual
Telephone
socket
TEL1
Fig. 2-1 External parts of the facsimile machine
Line
socket
LINE
2-1

2.1.1 Console

PQRS
WXYZ
Fig. 2-2 Console layout
The console comprises:
a display consisting of 2 lines of 16 characters each
a keypad consisting of:
- 11 function keys ( HOOK - START - STOP - S. DIAL - LAST TX - EXT. - HOLD -
FUNCTION - RX MODE - RESOL. - CONTR.) of which 7 are dual function keys
(CLEAR - VOLUME+ - VOLUME- - Aa - REDIAL - PAUSE - 2.TONE)
- 12 dual-function keys: for normal dialling (0 - 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 -
* - #) or user name setting (ABC - DEF - GHI - JKL - MNO - PQRS - TUV
- WXYZ - PT - &...)
- 10 keys for one-touch dialling
- 1 LED for indicating an ERROR.
2-2 XEROX DFC165 & DWC165c Service Manual

2.1.2 Functions of the console keys

Some keys perform different functions according to the current operating mode of the
facsimile machine:
Stand-by mode with document on the ADFStand-by mode without document on the ADF ƒ Function mode (activated by pressing the FUNCTION key), irrespective of
the presence of a document on the ADF
Hook mode (activated by pressing the HOOK key).
Key Mode Functions
•„ Used for dialling numbers.
Number keys ƒ Select alphanumeric characters for inclusion in the mne-
monic ID.
•„ In pulse dialling mode, changes the dialling mode to tone.
In tone dialling mode, emits a tone on line for special network servces.
« ƒ Scrolls forwards through the special characters and sym-
bols available for the mnemonic ID or selects the + character
for the user's telephone number.
•„ In tone dialling mode, emits a tone on line for special network
services.
# ƒ Scrolls backwards through the special characters and
symbols available for the mnemonic ID.
FUNCTION •‚ Provides access to operator selection menus and
submenus.
RX MODE •‚ Changes the reception mode : automatic, manual, FAX/
TEL, FAX/TAD.
CLEAR •‚ƒ Clears incorrect settings.
RESOL. Selects the type of resolution.
< ƒ Moves the cursor left during entry of the user's name and
number.
- VOLUME Reduces the volume of the speaker.
XEROX DFC165 & DWC 165c Service Manual
>>
2-3
Key Mode Functions
CONTR. Selects the type of contrast.
> ƒ Moves the cursor right during entry of the user's name and
number.
VOLUME + ‚„ Increases the volume of the speaker.
S. DIAL •‚ Enables the setting of a two-digit code for speed dialling.
Aa ƒ Changes from capitals to small letters (or vice versa)
during entry of the mnemonic ID.
LAST TX •‚ Pressed once, displays the result of the last transmission.
REDIAL •‚ Pressed twice, redials the last number.
EXT. When the facsimile machine is connected to a private branch
exchange, enables access to the public line .
PAUSE •‚ƒ Inserts a pause in automatic dialling and in speed and one-
touch dial settings.
HOLD Puts a telephone call on hold.
2. TONE •‚ Sets the second tone in automatic dialling and in speed and
one-touch dial settings.
HOOK •‚ Enables the user to dial the number without lifting the
receiver and to monitor the tones through the speaker.
Start one-touch dialling the fax number associated with
the key.
Keys 01-10 Enable the telephone number associated with the key to be
dialled when the START key is pressed.
ƒ Used for programming a one-touch dialling number.
Switches off the ERROR LED.
Stops copying, sending or receiving a document.
STOP ƒ Sets the facsimile machine in standby mode.
>>
2-4 XEROX DFC165 & DWC165c Service Manual
Key Mode Functions
Starts copying the document on the ADF.
After the number has been dialled, starts sending the document on the ADF.
START After a one-touch dial key has been pressed, starts dialling
the programmed telephone number.
After the receiver has been lifted, sets the facsimile machine in manual reception mode.
ƒ Confirms menus, submenus, parameters and values. Sets the facsimile in manual reception mode.
XEROX DFC165 & DWC 165c Service Manual
2-5

2.2 ELECTROMECHANICAL PARTS

2.2.1 Motors

Rear right-hand side
paper motor
Rear left-hand side
carriage motor
ink drain motor
Fig. 2-3 Locating the motors
2-6 XEROX DFC165 & DWC165c Service Manual
scanner motor

2.2.2 Sensors

document
end sensor
document sensor
console sensor
Fig. 2-4 Locating the console sensors
Printer
cover
sensor
paper sensor (under paper guide cradle)
Fig. 2-5 Locating the paper and printer sensors
Fig. 2-6 Locating the carriage sensor
paper edge sensor
XEROX DFC165 & DWC 165c Service Manual
2-7

2.2.3 Speaker

speaker
Fig. 2-7 Locating the speaker
2-8 XEROX DFC165 & DWC165c Service Manual

2.3 ELECTRONIC PARTS

Figure 2-8 shows the boards assembled on the facsimile machine.
3
4
5 6 7
8
2
1
Fig. 2-8 Locating the boards
1. Console board
2. CCD board
3. Power supply board
4. Print head driver board (in the print carriage)
5. Network control unit (NCU) board
6. Parallel port card (LinkFax model, only)
7. Motherboard
8. LED array for illuminating the documents.
XEROX DFC165 & DWC 165c Service Manual
2-9

2.3.1 General Block Diagram

Mains voltage
Display
Power supply
board
Console
board
Optical
unit
Scanner
unit CCD
board
Telephone
network
Motherboard
NCU
board
Telephone
Telephone
orTAD
Print unit
Print
carriage
Driver board
Parallel
port card
PC
(LinkFax model
only)
Fig. 2-9 General block diagram
The facsimile machine comprises the following main units:
Motherboard
Network control unit (NCU) board
Console board, with the display
Power supply board
Parallel port card, for connectiion
to the PC (LinkFax model, only)
2-10 XEROX DFC165 & DWC165c Service Manual
Optical unit, consisting of the scan­ner unit and CCD board
Printer unit, consisting of the print head driver board (in the carriage) and the carriage drive mechanism.

2.3.2 Block Diagram of the Motherboard

The motherboard controls the entire machine by means of a central processing unit (CPU) which uses special circuits to handle four main functional units: the image processor (for processing the scanned document), the motors (for activating all the mechanical parts), the print head (for printing both received and copied documents) and the modem (for controlling the signals to and from the telephone network).
CPU
I/O channel
controller
Modem
Image
processor
256 kB
EPROM
8 kB
static
memory
Custom
component
ASIC
512 kB dynamic memory
Step motor
driver
Step motor
driver
to print
head
to print
head
driver
to carriage
motor
to paper
motor
to scanner
motor
to CCD
board
to NCU
board
Telephone
network
Fig. 2-10 Block diagram of the motherboard
XEROX DFC165 & DWC 165c Service Manual
to console
board
to ink drain
motor
to the
parallel
port card
PC
2-11
1 2 3 4 5 6
7 8 9 10 11 12 13 146
Fig. 2-11 Locating the motherboard components
1 CUSTOM COMPONENT ASIC 2 MODEM CIRCUITS 3 STATIC RAM (8 x 8 kbytes) 4 QUARTZ CRYSTAL FOR MODEM
CLOCK (20.736 MHz)
5 QUARTZ CRYSTAL FOR SYSTEM
CLOCK (16 MHz)
6 PAPER, SCANNER AND INK DRAIN
MOTOR DRIVERS
7 BACK-UP RECHARGEABLE BATTERY
FOR DYNAMIC RAM (Ni-Cd, 3 volts, 72-hour duration)
8 SYSTEM BATTERY (Lithium, 3
volts, 5-year duration)
9 QUARTZ CRYSTAL FOR ASIC (16
MHz) 10 DYNAMIC RAM (512 kbytes) 11 SYSTEM FIRMWARE EPROM (256
kbytes) 12 QUARTZ CRYSTAL FOR RTC
(32.768 kHz) 13 CPU (WITH BUILT-IN MODEM AND
IMAGE PROCESSOR) 14 CARRIAGE MOTOR DRIVER
2-12 XEROX DFC165 & DWC165c Service Manual
The memory block, divided into the following three sections, is an integral part of
the motherboard:
EPROM
Static
RAM
EPROM (256 Kbytes), this memory contains the system firmware, the default settings of the software parameters and the messages in the various languages
STATIC RAM (8 kbytes), this memory contains:
- the current user and service software parameters
- the calibration settings (alignment settings, CCD settings)
- the telephone number list (one-touch dialling numbers, speed code
dialling numbers, broadcasting lists)
- the power failure repor .
DYNAMIC RAM (512 kbytes), this memory contains:
Dynamic
RAM
- the compression and decompression buffer
- the scanning buffer
- the print buffer
- the transaction memory (activity reports)
- the user memory (documents to send, documents received in the memory).
The data is retained in the dynamic memory even during a power failure by a backup
battery capable of powering the system for 72 hours. The facsimile machine must be left powered for 24 hours to recharge this battery.
The data is retained in the static memory by the 5-year duration system battery.
XEROX DFC165 & DWC 165c Service Manual
2-13

2.3.3 Block Diagram of the Network Control Unit Board

The NCU (Network Control Unit) board acts as the physical interface with the telephone line. The NCU board is available in several versions, to suit the specific needs of each country.
The figure shows the block diagram of a generic NCU board.
external TAD
interface
Current
Call
detector
detector
Receiver
detector
relay
Motherboard
TX
Amplifier
RX
Selector
Line
transf.
Selector
relay
relay
Fig. 2-12 Block diagram of a generic NCU board
Telephone line Telephone
2-14 XEROX DFC165 & DWC165c Service Manual

2.3.4 Block Diagram of the Power Supply Board

2 A
Fuse
Mains voltage
Voltage reg.
Mains filter
Switching
transformer
Primary rectifier
Diode rectifier
Switching controller
MOS
Fig. 2-13 Block diagram of the power supply board
+24 V
+28 V
+5 V
+12 V
-12 V
The power supply board provides a maximum power of 35 Watts and supplies, via
the switching circuit, the following direct voltages:
- +28 VDC (±10%), for the motors, variable according to the load
- +24 VDC (±2%), for the print head
- +12 VDC (±10%), for CCD, NCU and logic circuits
- -12 VDC (+10% -15%), for CCD and logic circuits
- +5 VDC (±5%) for sensors and logic circuits.
XEROX DFC165 & DWC 165c Service Manual
2-15
1 2 3 4 5
6 7 8 9
Fig. 2-12a Locating the power supply components
1 Mains filter
PF +28 V GND GND GND +24 V +5 V +12 V
-12 V
4 Stabilizer
to motherboard
7 Fuse (2 A) 2 Primary rectifier 3 Switching controller MOS
2-16 XEROX DFC165 & DWC165c Service Manual
5 +24 VDC regulator 6 Mains connector
8 Transformer
9 Diode rectifier

2.3.5 Printer Unit

The facsimile machine has a bubble ink jet system which uses a special head and prints
on plain paper.
The bubble ink jet print head consists of an interchangeable cartridge, which contains a sponge soaked with liquid ink, which is ejected from 50 nozzles made of a nickel and gold component, under the control of the signals that reach an electrical circuit consisting of 50 resistors (Fig. 2-13).
electrical
circuit
nozzles
sponge
cartridge
Fig. 2-13 Composition of the print head
Each nozzle generates a drop of ink when the corresponding resistor is pow­ered (+24 Volt) for a few microseconds.
The resistor is heated and the ink that is in direct contact with it evaporates, ex­panding like a bubble and pressing the rest of the ink against the nozzle.
nozzle
resistor
bubble
+24V
ink
XEROX DFC165 & DWC 165c Service Manual
+24V
2-17
As a result, a drop of ink is ejected from the nozzle at a speed of 15 metres a second until it strikes the paper on which it makes a dot.
drop
15 m/s
+24V
When the resistor is powered off, the bubble collapses quickly, drawing from the sponge a quantity of ink equal to the amount ejected. 800 microseconds after the ink has been ejected, the nozzle is ready to eject another drop.
dot
bubble
0V
2-18 XEROX DFC165 & DWC165c Service Manual
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