Original Size Detection 2 - Canon DADF-Q1 Service Manual

2.3.4 Original Size Detection 2

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.
Default size
A5, A4R
A4, A3
B5R
If the original is identified
as being large-size
ADF controller PCB
Reflected light detected
Original
S7
Slide guide
SSW0
ON
ON
ON
ON
ON
ADF controller PCB
S7
If the original is identified
as being small-size
ADF controller PCB
Reflected light absent
Original
F-2-15
ADF controller PCB
Original width
detecting switch (SW301)
F-2-16
T-2-3
SSW1 SSW2
ON OFF
OFF OFF
OFF OFF
OFF OFF
OFF OFF
S7
SSW3 SSW4
ON ON
ON ON
ON OFF
OFF OFF
OFF ON
Chapter 2
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