Overview; Scanner Motor Fault Detection - Canon LBP6000 Series Service Manual

Table of Contents

2.3.4.3 Overview

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.

Engine controller

CPU

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

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.

ASIC

+24VA

Frequncy

comparator