Controlling The Main Motor - Canon NP6330 Service Manual

CHAPTER 2 OPERATIONS AND TIMING
D. Controlling the Main Motor
1. Outline
The copier's main motor (M1) is a DC motor with a built-in clock pulse generator.
Figure 2-104 is a block diagram showing the circuit used to control the main motor, and
the circuit has the following functions:
Turning on and off the main motor.
Controlling the speed of the main motor.
Checking the rotation of the main motor for an error.
2. Operation
Turning On and Off the Main Motor
When the main motor drive command (MMD) from the DC controller goes '1', the
motor driver generates the drive command to turn on the main motor (M1). When the
MMD command goes '0', on the other hand, the drive command stops to turn off the
main motor.
Controlling the Speed of the Main Motor
When the main motor rotates, the hall IC generates pulse signals. The crystal
oscillator on the main motor driver PCB is used to generate reference pulses. These two
types of signals are sent to the phase control circuit; the phases of the frequencies of the
hall IC output pulses and the reference pulses are compared, and the output timing of
the drive signal to the main motor is controlled so that the phases match, causing the
speed of the motor to remain at a specific value.
Checking the Main Motor for an Error
The motor driver keeps the main motor lock signal (MMLOCK) at '0' as long as the
main motor is rotating at a specific speed. If a discrepancy occurs in the rotation of the
main motor for some reason, the MMLOCK signal goes '1'.
The DC controller identifies a main motor error if the MMLOCK remains '1' for about
2 sec, and stops the main motor and, at the same time, indicates 'E010'.
2-6
COPYRIGHT © 1997 CANON INC.
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CANON NP6330 REV.0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)