IV. OTHERSA. Original Size Detection1. Outline of DetectionThe machine is equipped with auto paper selection and auto ratio selection func-tions, which necessitate the identification of the size of originals.As many as four original detection circuits are mounted under the copyboard glass(Figure 3-401). The outputs of these circuits are checked by the DC controller when thecopyboard cover is closed so as to identify the original as being A3, B4, A4, or B5.An original detecting circuit consists of an LED which emits light against the originaland a phototransistor which checks the light reflected by the original for output to the DCcontroller.Figure 3-401A4B5A4RB5RA3B5 A4 B5R A4R B4 A3Phototransistor LED PS5Copyboard coveropen/closedsensorOriginal detectioncircuit 2Original detection circuit 3Original detectionsignal 3Original detection signal 2Original detectionsignal 0Original detection signal 1Copyboard cover detection signal 1DC controller PCBOriginaldetectioncircuit 0Originaldetectioncircuit 1CHAPTER 3 EXPOSURE SYSTEM3-20 COPYRIGHT © 1997 CANON INC. CANON NP6560/NP6360/NP6260 REV. 0 NOV. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
