The rotation speed control circuit compares
the scanner speed signal and the clock pulses
(M2CLK) generated by the scanner motor and
sends control signals to the motor drive circuit
according to the difference.
The motor drive circuit does not change the
voltage applied to the motor but rather turns
ON/OFF the power to the motor at short intervals
(while keeping the voltage constant), thereby con-
trolling the speed by varying the intervals.
The DC controller PCB generates the repro-
duction ratio selection signal (M2MD0, 1, 2) as
shown in Table 3-203 to change the speed of
scanner motor according to the selected repro-
duction ratio.
Table 3-203
3. OPERATIONS AND TIMING
COPYRIGHT © 1996 CANON INC.
CANON NP6085 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-46
M2
MD2
M2
MD1
M2
MD0
DC
controller
PCB
Scanner
motor
driver PCB
Motor stop
circuit
0
0
0
0
1
200%~
172%
0
1
0
171%~
151%
0
1
1
150%~
91%
1
0
0
92%~
72%
1
0
1
71%~
68%
64%~
62%
1
1
0
67%~
64%
61%~
50%
1
1
1
Motor drive circuit
0
Figure 3-216
Copy Start key ON
Scanner forward signal
(M2F/R)
Scanner motor drive
signal (M2ON)
Scanner speed control
signal (M2FS)
Scanner stop signal
(M2BRK)
INTR
SCFW
SCRV
Scanner home position
sensor (Q5)
Scanner original leading
edge 1 sensor (Q4)
LSTR
*2
*1
*1 Scanner slow-down braking
*2 Scanner stop braking