Canon PC920 Service Manual page 213

2. Identifying the Length of the Original
The registration paper sensor (PI2) is used to identify the length of the original, if any.
The ADF controller computes the length of the original based on the time it takes for the
original to move past the registration paper sensor (PI2).
Using the result of the computation, the ADF controller determines whether the size of the
original is A4/LTR or smaller or LGL, thereby switching to the appropriate ADF operation.
Table 8-101 shows the lengths of originals that determines ADF operation sequence.
COPYRIGHT © 1999 CANON INC.
ADF controller PCB
Figure 8-107
Original Lengths and Operation Sequences
Length
~313cm
314cm~
Table 8-101
CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Original
Original tray
PI3
PI2
Sequence
For A4/LTR originals
For LGL originals
CHAPTER 8 ADF
8-7