Service manual
Chapter 2
2-37
2.6.2 DC Controller (DCNT)
2.6.2.1 Outline
0008-1725
The DCNT Board, which is controlled by the CPU in it, controls operation sequences for the printer.
When the power is turned on and DC power is supplied from the power supply unit to the DCNT Board PCB, the CPU starts to control the operations of the printer.
Then, when the printer enters the standby status, the CPU drives loads such as the laser diodes, motors, solenoids, etc. based on a print command and image data
input from the interface controller.
F-2-52
2.6.2.2 Operations
0008-1726
a. CPU (IC101)
A 16-bit single-chip microcomputer is used for a CPU. It has a built-in ROM and RAM. It controls the following operations according to a program stored in the
ROM:
1) Printer engine sequence control
2) Drive controls for the developing rotary motor, toner cartridge motor, fixing motor, engaging motor
3) Drive control for the cooling fan
4) Internal temperature detection thermistor control
5) Reading/writing to the non-volatile memory
b. ASIC (IC102)
The ASIC (Application Specific IC) is an IC used for interface of IC, memory, external device, etc. It controls the following operations according to the CPU:
1) Laser/scanner control
2) Control of communications with the interface controller
3) Power supply unit (fixing control circuit, low-voltage power supply circuit) control
4) High-voltage power supply PCB control
5) Drive control for the main motor
6) Sensor/switch controls
7) Clutch/solenoid controls
8) Reading/writing to the memory tag
9) 250-sheet paper feeder (option) control
c. Reset IC (IC105)
It monitors +3.3 V and resets the CPU and ASIC when the power is turned on.
d. Non-volatile memory (IC109)
It stores backup data.
IC 101
CPU
IC 102
ASIC
DCNT Board
250-sheet
paper feeder
(option)
H.V.T,
Sub-H.V.T
Fixing unit
Low-voltage
power supply
circuit
Fixing
control circuit
AC input
+3.3V
+5V
+24V
Power supply unit
Laser driver
BD circuit
Scanner
motor
Laser/scanner unit
T
oner cartridge
× 4
Main motor
Solenoids
×
2
Clutches
×
2
Toner
cartridge
motor
Cooling fan
Switch
×
1
Sensors
×
8
/BDI
Fixing motor
Engaging
motor
IC 106
Fixing motor
driver IC
IC 107
Engaging motor
driver IC
IC104
T
oner cartridge
motor driver IC
IC109
Non-volatile memory
Developing
rotary motor
Drum cartridge
IC105
Reset IC
/RESET
IC103
Developing rotary
motor driver IC
Fan motor
control circuit
Internal
temperature
detection
thermistor
Memory tag
: Multiple control lines
:Single control line
:
AC line
Memory tag
SCNT Board