Canon NP6218, FY8-13EX-000 service manual Driving the Scanner Motor Outline, Mechanism

CHAPTER 3 EXPOSURE SYSTEM

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) 3-7