Brother DX-2000 User manual

MECHANICS & ELECTRONICS
SERVICE MANUAL
LASER PRINTER
DX-2000

i
CONTENTS
CHAPTER I GENERAL....................................................................I-1
1. SPECIFICATIONS...........................................................................................I-1
CHAPTER II MECHANICAL SYSTEM............................................II-1
1. BLOCK DIAGRAM..........................................................................................II-1
2. PAPER FEED MECHANISM ..........................................................................II-1
3. PAPER FEED SEQUENCE............................................................................II-2
4. PAPER PRESSER MECHANISM...................................................................II-3
CHAPTER III ELECTRICAL SYSTEM...........................................III-1
1. COMPOSITION .............................................................................................III-1
2. MAIN PCB FUNCTION..................................................................................III-1
2.1 I/F Circuit .......................................................................................................................III-1
2.2 Regulator.......................................................................................................................III-1
2.3 Fan Drive Circuit............................................................................................................III-1
2.4 Motor Drive Circuit.........................................................................................................III-1
2.5 Solenoid Actuator ..........................................................................................................III-1
2.6 Sensor Input ..................................................................................................................III-1
3. I/F PCB ..........................................................................................................III-2
4. COMMUNICATION WITH THE PRINTER.....................................................III-2
CHAPTER IV DISASSEMBLY......................................................IV-1
1. EXTERNAL COVERS................................................................................... IV-1
1.1 Composition.................................................................................................................. IV-1
1.2 Side Cover R ................................................................................................................IV-1
1.3 Side Cover L................................................................................................................. IV-3
1.4 Bottom Cover................................................................................................................ IV-4
1.5 Top Cover..................................................................................................................... IV-5
2. OUTSIDE FRAME UNIT............................................................................... IV-7
2.1 Composition.................................................................................................................. IV-7
2.2.1 Removing the outside frame unit from the Duplex unit................................................. IV-7
2.2.2 Mounting the outside frame unit in the Duplex unit....................................................... IV-9
2.3 Duplex I/F PCB........................................................................................................... IV-10
2.4 Outside Frame R Assy, L Assy...................................................................................IV-11
2.5 Paper Pressing Gear 1, 2........................................................................................... IV-12

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2.6 Paper Presser Motor................................................................................................... IV-13
2.7 T Belt B40S2M396...................................................................................................... IV-14
2.8 Photo Interrupter 1240................................................................................................IV-14
3. INSIDE FRAME UNIT................................................................................. IV-15
3.1 Reversible Frame ....................................................................................................... IV-15
3.2 Photo interrupter 1240................................................................................................ IV-15
3.3 Solenoid...................................................................................................................... IV-16
3.4 Carriage Guide 2 Assy................................................................................................ IV-16
3.5 Carriage Guide 1 ........................................................................................................IV-17
3.6 Duplex PCB Assy ....................................................................................................... IV-17
3.7 DC Fan Motor............................................................................................................. IV-18
3.8 Reversible Motor Assy................................................................................................ IV-19
4. DU TRAY CARRYING WAY UNIT.............................................................. IV-20
CHAPTER V TROUBLESHOOTING..............................................V-1
APPENDICES
1. CONNECTION DIAGRAM............................................................................. A-1
2. MOTOR DRIVE CIRCUIT.............................................................................. A-2
3. MAIN PCB CIRCUIT...................................................................................... A-3

I-1
CHAPTER I GENERAL
1. SPECIFICATIONS
(1) Paper type Cut sheet
Feedable paper weight : 60 ~ 105 g/ m2
(2) Paper size Max. : 216.0 x 356.0 mm
Min. : 182.0 x 257.0 mm
A4, Letter, Legal, Executive, ISO B5 (not available for
the optional lower paper cassette)
(3) Input power supply 24V DC ± 10%, max. 0.7 A (supplied from the printer)
(4) Feeding system Type :Reversal type
Paper feeding system :Alternate paper feeding system
(5) Paper feed Paper feeding rate : 117.6 mm/sec. (20 ppm)
94.1 mm/sec. (16 ppm)
70.6 mm/sec. (12 ppm)
Feedable paper size :A4 210.0 x 297.0 mm
Letter 215.9 x 279.4 mm
Legal 215.9 x 355.6 mm
Executive 184.2 x 266.7 mm
B5 182.0 x 257.0 mm
(6) Dimensions 323.0 (W) x 105.0 (D) x 286.0 (H) mm
(7) Weight 5.4 kg
(8) Environmental conditions
1) Operating Temperature : 10°C ~ 32.5°C
Humidity : 20% RH ~ 80% RH (No dew
condensation allowed)
2) Idling Temperature : 0°C ~ 35°C
Humidity : 10% RH ~ 80% RH (No dew
condensation allowed)
3) Storage
Store the unit under the following conditions to ensure reliable performance.
Normal (90% of entire storage period) 0°C ~ 35°C
Temperature Severe (10% of entire storage period) High 35°C ~ 60°C
Low -20°C ~ 0°C
Temperature variation (within 3 minutes) 60°C →15°C
-20°C→25°C
Normal (90% of entire storage period) 35%RH ~ 85%RH
Humidity* Severe (10% of entire storage period) High 85%RH ~ 95%RH
Low 10%RH ~ 35%RH
Air pressure 613 ~ 1013hPa
Storage life 0.5 years
*No dew condensation allowed

I-2
4) Transportation conditions
Environment :
Temperature -20°C ~ 60°C
Humidity 95%RH or below
5) Vibration
Vibration
acceleration Vibration frequency Measuring method
During operation 0.2 G 5 ~ 100 Hz Refer to the evaluation test standard.
At standby 0.2 G 5 ~ 100 Hz Same as above.
When packed 1.5 G 10 ~ 100 Hz Same as above.
6) Inclination The feeder must operate properly even at an
inclination angle of 2.
7) Mechanical noise During printing : 55 dB (A) or below
At standby : 40 dB (A) or below
(9) Interface
1) Connector signal table (8 pin modular jack)
Pin Signal name
1 24V
2 SIDATA
3 24V
4 SICLK
5 GND
6 /ATTN
7 /RESET
8 GND
2) Interface circuit
5V
5V
0V
Connector
74LS07 or equivalent

II-1
CHAPTER II MECHANICAL SYSTEM
1. BLOCK DIAGRAM
The Duplex unit is composed of an outside frame, an inside frame and a Duplex tray, and
operates according to signals sent from the printer in serial communication.
Fan motor
Reversible motor
Reverse sensor
Solenoid
Main PCB
Inside frameOutside frame
Printer Open cover sensor
Paper pressure motor
Cassette sensor
Serial
communication
Duplex tray
I/F PCB
Figure 2.1
2. PAPER FEED MECHANISM
As soon as the printer requests for drive, a signal from the main PCB turns on the
solenoid to run the reversible motor clockwise (when viewed from the motor output shaft).
The Duplex unit will draw paper from the printer by turning on the solenoid.
The supplied paper is further transferred by the reversible motor driven reversible gears.
When the reverse sensor detects the rear end of the paper, the reversible motor comes
to a momentary stop, and begins running counterclockwise.
Then the reversible motor enables the carriage rollers to feed the paper into the Duplex
tray installed within the Duplex unit. With the printer’s Duplex sensor on, the Duplex unit
stops the reversible motor by a request from the printer.
One cycle of paper feeding operation is completed in this way.
Duplex unitPrinter
Solenoid
Du carriage roller
Reversible
motor
Reversible gear
Reverse
sensor
Main PCB
Duplex sensor
Pick up roller
Photosensitive drum Positioner
Figure 2.2

II-2
3. PAPER FEED SEQUENCE
(1) As soon as the printer requests for Duplex drive,
the solenoid is turned on, the flapper is switched,
and the motor runs forward.
(2) The reverse sensor is monitored to measure the
time from when the solenoid is turned on to when
the sensor is turned on.
If the sensor has not turned on after a specified
time passed, it is deemed that paper jam has
occurred.
(3) The solenoid is turned off in response to
instructions from the printer, and the flapper is
returned as it was before.
After the reverse sensor is turned on, the time up
to when the paper has passed through the reverse
sensor is monitored.
If the sensor has not turned off within a specified
time, it is deemed that paper jam has occurred.
(4) Immediately after the reverse sensor is turned off,
the motor begins through-down, stops for a
specified time, and runs backward.

II-3
(5) As soon as the printer requests for stop, the motor
stops and goes into a standby state.
•• Paper Feed Timing Chart
(when only one piece of A4 paper is reversed and printing speed is 12 ppm)
4.84 sec*
3.2 sec*
1.3 sec* 4.21 sec*
0.1 sec
C.W C.C.W
Solenoid
Reversible
motor
Reverse
sensor
Duplex
sensor
Duplex drive request from the printer
Figure 2.3
* The paper feed timing varys in the printing speed.
For 16 ppm, 12/16 times the above values.
For 20 ppm, 12/20 times the above values.
4. PAPER PRESSURE MECHANISM
Upon a request from the printer, the paper pressure unit built in the Duplex tray is moved
up or down by the paper pressure motor connected to the I/F PCB.
The paper pressure unit is moved up only when the first tray is selected on the printer to
supply paper, or down when paper is fed from another tray.
The cassette sensor detects the position of the paper pressure unit, and whether the
Duplex tray is loaded into the Duplex unit.
I/F PCB
Paper pressure motor
Cassette sensor
Paper pressure unit
Figure 2.4

III-1
CHAPTER III ELECTRICAL SYSTEM
1. COMPOSITION
Regurator
I/F circuit
GND
+24V +5V
Fan drive circuit
Motor drive circuit
CPU
M50927
I/F PCB
Printer
Main PCB
Figure 3.1
2. MAIN PCB FUNCTION
2.1 I/F Circuit
This interface circuit is used to transmit and receive data with the printer. Since the
Duplex unit responds only to commands from the printer, the Duplex unit transmits its
status upon request from the printer.
2.2 Regulator
The regulator produces +5V logic power supply from the +24V supplied by the printer.
2.3 Fan Drive Circuit
This circuit drives the cooling DC fan.
The fan rotation speed is switched between two different levels according to the signal
from the CPU. It operates at high speed when the Duplex unit feeds paper, or it runs at
low speed while the unit is not in operation.
When the DC fan functions properly, it sends a /FLOCK signal to the CPU to confirm that
it is normal.
2.4 Motor Drive Circuit
According to the signal from the CPU, this circuit drives both the reversible motor and the
paper pressure motor.
2.5 Solenoid Actuator
According to the signal from the CPU, this actuator turns the solenoid on or off.
2.6 Sensor Input
Signals to each of the reverse sensor, cassette sensor and open cover sensor are
imported to the CPU port.

III-2
3. I/F PCB
The I/F PCB consists of two connectors (8-pin modular jack connectors) for connection of
the printer to other optional devices, a paper pressure motor, a cassette sensor, an open
cover sensor connector, and a connector for connection of the harness from the main
PCB.
This board only relays signals among the paper pressure motor, cassette sensor, open
cover sensor and printer and the main PCB.
4. COMMUNICATION WITH THE PRINTER
A 3-line clock synchronous serial interface is used for communication between the
Duplex unit and the printer.
The following describe the timing of communication way.
GND
DATAOUT
DATAIN
CLKOUT
/ATNOUT
/OPRST
+24V
GND
+24V
/OP RESET
/ATTN
SICLK
SIDATA DATAIN
DATAOUT
CLKIN
/ATNIN
/RESET
REG.
Printer Duplex unit
GND
+5V
+24V
Figure 3.2

III-3
6.4 min
/ATTN
SICLK
SIDATA
500 max
50 µs 12.8 µs 350 max 150 min
500 min200 µs
6.4 min6.4 min
350 max
400 min4µs
D0 D1 D2 D3 D4 D5 D6 D7
COMMAND transmission/receipt sequence
/ATTN
SICLK
SIDATA
500 max 50 µs 350 max
200 µs
200 µs
6.4 min
350 max
400 min4µs
COMMAND transmission/receipt sequence
• Within a STATUS request
• Without a STATUS request
350 max
D0 D1 D2 D3 D4 D5 D6 D7
500 min
70 µs/1000 max 350 min
STATUS transmission/receipt sequence
350 max
150 µs12.8 µs
D0 D1 D2 D3 D4 D5 D6 D7

IV-1
CHAPTER IV DISASSEMBLY
1. EXTERNAL COVERS
1.1 Composition
Figure 4.1
1.2 Side Cover R
(1) Push the lock lever cover, turn and open the inside frame unit.
Figure 4.2
Side cover R
Lock lever cover
Side cover L
Top cover
Bottom cover
Lock lever cover
Lock lever cover
Outside frame unit
Inside frame unit

IV-2
(2) Loosen the screw fastening the side cover R.
Figure 4.3
(3) Using a small minus screwdriver, disengage the six hooks to remove the side
cover R from the outside frame R and the bottom cover.
(4) Separate the side cover R from the Duplex unit.
Figure 4.4
Side cover R
Outside frame R
Bottom cover
Hooks
Hooks
Hooks
Taptite, bind B M3 x 6
Side cover R

IV-3
1.3 Side Cover L
(1) Unfasten the screw fastening the side cover L.
Figure 4.5
(2) Using a small minus screwdriver, disengage the five hooks to remove the side
cover L from the outside frame L and the bottom cover.
(3) Separate the side cover L from the Duplex unit.
Figure 4.6
Side cover L
Taptite, bind B M3 x 6
Side cover L
Outside frame L
Bottom cover
Hooks
Hooks

IV-4
1.4 Bottom Cover
(1) Turn and close the inside frame unit.
(2) Lay down the Duplex unit on the side to face up the bottom cover.
(3) Loosen the two screws.
Figure 4.7
(4) Disengage the engaging locks of the bottom cover from the outside frame L, and
separate the cover from the Duplex unit.
Figure 4.8
Bottom cover
Taptites, cup S M3 x 6
Bottom cover
Engaging locks
PR99079

IV-5
1.5 Top Cover
(1) Place the Duplex unit with the bottom down.
(2) Pushing the lock lever cover, turn and open the inside frame slightly. (approx.
30°)
Figure 4.9
(3) Disengage the hook of the lock lever cover by using a minus screwdriver, and pull
out the cover slantingly.
Figure 4.10
Lock lever cover
Hook
Top cover
Lock lever cover
Outside frame unit
Lock lever cover
Approx. 30°
Inside frame unit

IV-6
(4) Loosen the four screws (two on each side).
Figure 4.11
(5) Slide up the top cover to disengage the five engaging locks from the inside frame
unit, and separate the top cover from the Duplex unit.
Figure 4.12
Taptites,
cup S M3 x 6
Taptites,
cup S M3 x 6
Top cover
Top cover
Push the bosses in these holes,
and remove the
g
ear cover.
Gear cover
Engaging locks
Engaging locks
Top cover Inside frame unit

IV-7
2. OUTSIDE FRAME UNIT
2.1 Composition
Figure 4.13
2.2.1 Removing the outside frame unit from the Duplex unit
(1) Turn and close the inside frame unit.
(2) Disconnect the relay harness assy from the Duplex I/F PCB assy and the edge
saddle.
(3) Pull out the fulcrum shaft R by using pliers.
(4) Remove the fulcrum spring.
Figure 4.14
Paper pressure motor
Carriage guide 3
Outside frame L assy
Outside frame R assy
Tower bars
Inside frame unit
Fulcrum shaft L
Bearing collar
Fulcrum shaft R
Fulcrum spring
Retaining ring E6
Retaining ring E4 Outside frame unit

IV-8
Figure 4.15
(5) Slide the R side of inside frame unit toward you to remove it from the fulcrum
shaft L and the outside frame unit.
Figure 4.16
Outside frame unit
Fulcrum shaft L
Inside frame unit
R side
Edge saddle
Relay harness assy
Duplex I/F PCB assy

IV-9
2.2.2 Mounting the outside frame unit in the Duplex unit
(1) Keeping the inside frame unit slantwise, mate the hole for the fulcrum shaft L of
the inside frame unit with the fulcrum shaft L.
Note1 : Do not get the relay harness assy caught between the inside
frame unit and the outside frame unit.
Note2 : If the solenoid assy harness is slack, stretch it.
(2) Turn the inside frame unit on the fulcrum shaft L to set it in the outside frame unit.
Figure 4.17
(3) Insert one end of the fulcrum spring in the hole in the outside frame unit.
Figure 4.18
Solenoid assy harness
Solenoid
Outside frame unit
Relay harness assy
Fulcrum shaft L
Hole for the fulcrum shaft L
Inside frame unit
Inside frame unit
Fulcrum spring
Hole in the outside frame unit
Outside frame unit