3–24OPERATIONS AND TIMINGCOPYRIGHT © 1998 CANON INC. CANON NP6621 REV.0 FEB. 1998 PRINTED IN JAPAN (IMPRIME AU JAPON)when the copyboard cover is closed and identify theoriginal as being any of the default paper sizes.Each original size sensor consists of a LED anda phototransistor: the LED illuminates the original,and the photodiode receives the reflected light andsends the output to the DC controller circuit.The size of originals in the DF (option) is identi-fied by the DF and communicated to the machine.When the DF is used, the machine executes autopaper selection, auto reproduction selection, re-duction layout, and enlargement layout based onthis size data.J. Original Size DetectionControl1. OutlineThe machine offers auto paper selection, autoreproduction selection, reduction layout, and en-largement layout functions, all of which require theidentification of the size of the originals being used.To identify the size, the machine has two to fouroriginal size sensors under its copyboard glasswhich check the presence/absence of an originalFigure 3-123 (A configuration)A4 A3A4RPS11Copyboard cover open/closed sensorDC controller PCBOriginal size sensor 1Original size sensor 2
