Moving The Lens - Canon NP6251 Service Manual

CHAPTER 3 EXPOSURE SYSTEM

4. Moving the Lens

a. At Power-On
When the power switch is turned on, the lens X motor (M4) starts to rotate, and the
lens moves in the direction of the lens X home position sensor (PS6). Then the lens Y
motor (M5) rotates to move the lens in the direction of the lens Y home position sensor
(PS7). When the signal plate on the lens housing blocks the lens X home position sensor
(PS6), the X motor starts to rotate in reverse; when the signal plate on the lens stage
blocks the Y home position sensor (PS7), the lens Y motor (M5) starts to rotate in
reverse.
The motors stop to rotate when the lens has reached Direct/A4 width position. (See
period I of Figure 3-204.)
b. While Making Copies
The microprocessor slave (Q140) remembers the location of the lens in Direct/A4
position. When a different ratio is selected, it immediately applies drive pulses to the lens
X motor (M4)/Y motor (M5) to change the position of the lens. (See period II of Figure 3-
204.)
The lens Y motor (M5) starts to rotate to move the lens when the Copy Start key has
been pressed and the sizes of the original and the copy paper have been determined.
(See period III of Figure 3-204.)
• Sequence of Operations
Lens X motor (M4)
Lens Y motor (M5)
Lens X home
position (PS6)
Lens Y home
position sensor (PS7)
3-4
COPYRIGHT © 1997 CANON INC.
Power switch Ratio change
ON (Reduce)
WMUP/WMUPR
I
Motor CW/sensor ON
Motor CCW
Motor ON (direction depends on conditions)
Figure 3-204
CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
Ratio change
(Enlarge)
STBY
II II
Copy Start key
ON
INTR
III