Canon DADF-Q1, Service Manual

Page: 33 / 156

Chapter 2
2-11
F-2-15
2.3.4 Original Size Detection 2
0011-2243
a. Outline
In original size detection 2, the original width detecting switch (SW301) and the registration roller clock sensor (PI5) are used to identify a default size.
The original width detecting switch is designed to find out the width of originals. As many as five contact plates (SSW0 through 4) are in contact with the original
width detecting switch, operating in keeping with the slide guide. The state (ON or OFF) of each contact plate is communicated to the ADF controller PCB, which
uses the input to determine the width of the original.
The following table shows the states of the contact plates in relation to default sizes; the states other than those indicated are assumed to indicate the presence of an
original which is not of a default size.
F-2-16
T-2-3
Default size SSW0 SSW1 SSW2 SSW3 SSW4
A5, A4R ON ON OFF ON ON
ON OFF OFF ON ON
A4, A3 ON OFF OFF ON OFF
ON OFF OFF OFF OFF
B5R ON OFF OFF OFF ON
ADF controller PCB
ADF controller PCB
If the original is identified
as being large-size
If the original is identified
as being small-size
ADF controller PCB
Reflected light detected Reflected light absent
S7 S7
S7
Original Original
T
AILS
Slide guide
ADF controller PCB
ON/OFF
Original width
detecting switch (SW301)