Initial Document Size Detection (Width Direction) - Canon DADF-H1 Service Manual

CHAPTER 2 OUTLINE OF OPERATION

2.3.5 Initial document size detection (width direction)

a. Overview
Initial document size detection (width direction) is accomplished by the document width
detection variable resistor (VR1) in the document tray. The document width detection vari-
able resistor works in synchronization with the slide guide to vary its resistance in an analog
form. The ADF controller receives changes in this resistance as a document size signal
(VR) and replaces it with a size in the width direction.
A dedicated A4R/LTRR identification sensor (PI2) in the document tray assures that
document width detection variable resistor (VR1) is able to detect the widths of A4R (210
mm wide) and LTRR (216 mm wide) accurately. The A4R/LTRR identification sensor gen-
erates a 1 on the A4/LT identification on detecting a document width that is 197mm or more
but less than 214mm.
Slide guide (rear)
2-20
ADF controller PCB
A4R/LTRR
identification sensor
Gear
Document width
detection variable resistor
F02-203-03
COPYRIGHT © 2001 CANON INC.
Slide guide (front)
2000 2000 2000 2000 CANON DADF-H1 REV.0 MAR. 2001