Outline; Main Motor Control Circuit; Mechanism - Canon NP6218 Service Manual

CHAPTER 2 BASIC OPERATION
D. Main Motor Control Circuit

1. Outline

Figure 2-104 shows the circuit used to control the main motor (M1); the circuit has
the following functions:
turns on and off the main motor.
controls the main motor to a specific rotation speed.
The main motor (M1) is a DC motor that has a built-in clock pulse generator. When
the motor rotates, it generates clock pulse signals (MMCLK*) according to the revolution
of the motor. The speed control circuit matches the phases of the frequency of these
clock pulses and that of the reference signals to control the main motor (M1) to a specific
revolution speed.

2. Mechanism

When the main motor drive signal (MMD) from the DC controller circuit goes '1', the
drive circuit of the motor driver turns on, thereby rotating the main motor (M1) at a
constant speed.
While the main motor is rotating at a specific speed, the motor driver PCB keeps
sending the specific speed state signal=0 (MLOCK*) to the DC controller PCB. If, for
some reason, an irregularity occurs in the rotation of the main motor, the MLOCK* signal
goes '1'.
If the main motor drive signal (MMD) remains '1' and the MLOCK*=0 remains
unchanged for about 1 sec, the DC controller identifies a main motor error and stops the
main motor and, at the same time, indicates 'E010'.
J 303
DC controller
PCB
J 303
2-4
J 206
+34V
J 501
- 1
- 2
J 502
- 3 - 2
MMD
J 502
- 4 - 1
MLOCK*
Reference signal
Figure 2-104
COPYRIGHT © 1997 CANON INC.
Drive circuit
Phase control
circuit
MMCLK
CANON NP6218 REV. 0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
Clock pulse generator
Drive
current
M1
Main motor
Hall IC output
Main motor driver PCB