Controlling The Belt Motor - Canon NP6412 Service Manual

H.

Controlling the Belt Motor

1. Outline
Figure 8-122 is a diagram showing the control circuit for the belt motor (M2).
The belt motor is a 4-phase control stepping motor.
The CPU (Q1) on the ADF controller PCB sends control pulse signals (A, A*, B, B*) to the
motor driver (Q4).
In response, the motor driver changes the output timing of the pulse signals (MA, MA*, MB,
MB*) used for driving the motor to rotate the belt motor clockwise or counterclockwise.
The motor driver is equipped with a limiter function used to keep the motor supplied with a
specific current so that current greater than specified will not flow.
If loads large enough to activate the limiter function occur in succession, the belt motor cannot
rotate as specified, possibly leading to feeding faults. Any feeding fault will cause the ADF con-
troller to flash the Jam indicator on the controller and stop the belt motor at the same time.
A
Q1
CPU
A*
B
B*
COPYRIGHT © 1999 CANON INC.
ADF controller PCB
Figure 8-122
CANON NP6512/6612/7120/7130/7130F REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
+24V
MA
Q4
Motor
driver
MA*
MB
MB*
CHAPTER 8 ADF
Belt motor
M1
8-15