D. Main Motor Control Circuit
1. Outline
Figure 2-101D shows the circuit that controls the main motor (M1), and the circuit
has the following functions:
a.
turns the main motor ON and OFF.
b.
controls the main motor speed (constant)
The main motor (M1) is a DC motor and is equipped with a motor rotation sensor
(Q901) to serve as a clock pulse generator. Clock pulses (MMCLK) corresponding to
the revolution of the motor are generated while the motor is rotating. The speed control
circuit controls the speed of the motor with reference to these clock pulses.
2. Operation
The drive circuit on the DC controller/DC power supply PCB causes the main motor
drive command (MMD) to go ‘0’ in response to instructions from the microprocessor,
thereby causing the main motor to rotate at a specific speed.
3. Overcurrent Sensor
When the overcurrent sensor circuit detects an overload in the main motor (M1), the
speed controller circuit exerts control so that the rotation of the motor is slowed down.
If the revolution of the main motor falls below a specific revolution, however, an error
associated with ‘E2’ can occur.
COPYRIGHT © 1998 CANON INC. CANON PC400/420/430,FC200/220 REV.0 JAN.1998 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 2 BASIC OPERATION
2-5
Overcurrent
detection
circuit
Q101
DC controller/DC power supply PCB
M1
Q901
Main motor clock pulse
signal (MMCLK)
Main motor drive
command (MMD)
J201
-5
-4
-1
(+)
(-)
Motor rotation detection PCB
+24V
Main motor
Microprocessor (Q101)
Speed control circuit
Drive circuit
Figure 2-101D
