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4. Driving the Scanner Motor
a. Outline
The scanner motor (M2) is a 4-phase control stepping motor. The direction and the
speed of the scanner motor (M2) are switched by controlling the output timing of drive
power SC-COMA and SC-COMB and pulse signals A, A*, B, and B*.
b. Mechanism
The microprocessor (Q301) on the DC controller PCB receives such instructions as
on copy mode and reproduction ratio from the control panel circuit; in response, it sends
drive pulses to the scanning motor (M2) through the motor drive circuit.
The scanner motor is a 4-phase control stepping motor, and is used to control the
sequence of drive pulses (SC-A through SC-B*) and frequency, thereby controlling the
direction of scans and speed.
The motor drive voltage ON/OFF switching circuit supplies or deprives the motor with
or of power, thereby controlling the motor drive.
The current switching control circuit sets the current that flows through the motor
according to the revolution, and the motor driver circuit controls the constant current
according to the value that has been set.
Figure 3-303
COPYRIGHT
©
1997 CANON INC. CANON NP6218 REV. 0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 3 EXPOSURE SYSTEM
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