Scanner Motor Drive System Operation - Canon NP6320 Service Manual

CHAPTER 3 EXPOSURE SYSTEM
D.

Scanner Motor Drive System Operation

The scanner motor is a 4-phase stepping motor, and rotates CW and CCW depending on the
combination of pulses (A, A*, B, B*) to each phase.
a. Clockwise Rotation
The scanner motor driver outputs pulses, and the motor rotates CW. This moves the lens in the
direction for reduction, and the scanner moves forward.
For reduction copying, the motor speed increases to move the scanner faster (forward).
b. Counterclockwise Rotation
The scanner motor is driven CCW by pulses of phase relationship opposite of that used to drive
it CW. This moves the lens in the direction for enlargement, and moves the scanner in reverse.
c. Mechanism
The motor driver circuit controls the direction and speed of the scanner motor based on the
following signals generated by the microprocessor on the DC controller:
• scanner motor drive command (SCMD*)
• scanner forward command (SCFW*)
• scanner speed control command (SCCLK)
The motor driver circuit operates as shown in Table 3-302 based on the combinations of
SCMD* and SCFW*.
When the scanner is moving forward, the number of SCCLK pulses is varied according to the
reproduction ratio selected; when the scanner is moved in reverse, however, the number remains
the same.
E202 is indicated if the scanner does not reach the home position within a specific time after it
has started to move.
3-8
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SCMD*
Forward
Reverse
Braking
Still
* '1' and '0' are reversed from previous states.
**'1' or '0' is maintained.
Table 3-302
COPYRIGHT © 1999 CANON INC.
SCFW*
0 0
0 1
0 *
1 **
CANON NP6320 REV.0 DEC. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)