![Canon GP405 Service Manual Download Page 74](http://html1.mh-extra.com/html/canon/gp405/gp405_service-manual_4161525074.webp)
CHAPTER 3 EXPOSURE SYSTEM
3-8
COPYRIGHT © 1999 CANON INC.
CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
When the copyboard cover is brought down to about 30¡, the photointerrupter (PS2) mounted
at the rear turns on (i.e., light-blocking plate covers PS2). For 15 sec or until the Copy Start key is
pressed after PS2 has turned on, the output level of each sensor is read at 0.1-sec intervals. The
machine will identify the presence of an original at the sensor if its output level remains the same,
and will then identify the size of the original according to specific combinations of sensor states
(Tables 3-301, -202). This way of identification enables the use of dark originals.
The output level of each sensor, however, will not change under the conditions a or b below; in
the case of c, A3 paper will be selected first (if the appropriate cassette is absent, the standard mode
cassette will be selected).
a.
An A3 dark original is used.
b.
A book original is used. (The thickness of a book prevents the copyboard cover from closing
enough, not changing the output levels of the sensors.)
c.
The copyboard cover is not closed. (PS2 remains off.)
Reference:
In the case of a, b, or c, the size of the original may be identified wrongly.
Figure 3-402
Paper sensor 2
Copyboard
glass
30
Original
Copyboard cover
PS2:ON
PS2:ON
Paper sensor 1
Copyboard cover
PS2:OFF
No change
in the level
Change in
the level
Summary of Contents for GP405
Page 16: ......
Page 44: ......
Page 66: ......
Page 84: ......
Page 86: ......
Page 112: ......
Page 114: ......
Page 126: ......
Page 128: ......
Page 162: ......
Page 232: ......
Page 234: ......
Page 276: ......
Page 306: ......
Page 308: ......
Page 344: ......
Page 358: ......
Page 408: ......
Page 410: ......
Page 418: ......
Page 453: ...COPYRIGHT 1999 CANON INC CANON 405 335 REV 0 JAN 1999 PRINTED IN JAPAN IMPRIME AU JAPON 14 35 ...
Page 454: ......
Page 662: ......
Page 676: ...A 14 COPYRIGHT 1999 CANON INC CANON 405 335 REV 0 JAN 1999 PRINTED IN JAPAN IMPRIME AU JAPON ...
Page 680: ......