DWC165c
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
XEROX DFC165 & DWC165c Service Manual
n
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- - A↔a - 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 - P→T - &...)
- 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 ADF
‚ Stand-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.
A↔a 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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