Canon LBP6000 Series, Руководство по обслуживанию

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Chapter 2
2-9
2.3.4.3 Overview
0025-1148
LBP6000 / LBP6000B
This is the control to rotate the scanner motor at a constant speed to emit the laser beam on the correct position on the photosensitive drum.
The following is the control circuit of the scanner motor.
F-2-8
The engine controller creates standard clock based on oscillation frequency of the oscillator (X300); the cycles of the standard clock is compared with that of BD
input signal (/BDI) with a frequency comparator and the rotations of the scanner motor is monitored.
The engine controller sends the scanner motor acceleration signal (ACC) and scanner motor deceleration signal (DEC) to the scanner motor driver according to the
detected rotation speed to control the rotation speed.
2.3.4.4 Scanner Motor Fault Detection
0025-1149
LBP6000 / LBP6000B
This is the detection of faults in the laser scanner unit.
When the laser unit scanner unit falls into either of the following status, the engine controller judges it as a fault in the laser/ scanner unit system and notices the
status of fault to the main controller.
The operations of the host machine are stopped.
1) Fault in BD input
At startup of the scanner, /BDI signal cannot be detected within 0.1 sec from the completion of forced acceleration of the scanner motor.
2) Fault in startup
During activating the scanner motor at startup of the scanner, the motor rotation exceeds the specified range (98.3 to 102.1%).
3) Fault in control
After startup of the scanner completes correctly, /BDI signal exceeds the specified value of cycle 10 consecutive times.
Engine controller
Motor driver PCB
BD PCB
Oscillator
Reference
clock
Frequncy
comparator
Laser/scanner unit
Integration
circuit
M
Scanner driver
Scanner motor
ACC
DEC
/BDI
Drive
circuit
CPU
ASIC
+24VA
+24VA