Canon iR3570 Service Manual page 202

Chapter 5
Start key
Main power switch
ON
ON
WMUPR STBY
Dust detection control
F-5-22
<Particulars of Control>
-At the End of a Job (dust detection)
The contact image sensor (CIS) checks the light reflected by the surface of the platen roller of the ADF at the read point for the presence/absence of dust. Presence
of dust is detected at points A, B, and C in this order. The point where least dust is detected will be used as the read position for the next job.
The point selected here will be used as the read position for the next job.
- For control at the end of a job, if an original is placed in the ADF with dust detected at all points (A, B, C), the machine will indicate a message on its control panel
to prompt cleaning of the glass surface. The Start key will remain invalid until this message is cleared.
-At the Start of a Job (dust bypass)
Presence of dust is detected at points A, B, and C in this order in the same manner as at the end of the job. Read will take place at the point where least dust is detected.
A
F-5-23
-Between Sheets
The machine does not move the contact image sensor (CIS) for dust detection between sheets. It reads the original using the position determined at the end or start
of a job; if the presence of dust is detected, however, the machine will execute image correction.
5-12
1st
SCAN
Dust detection control
B C
Point
A
B
C
2nd
SCAN
Dust detection control
T-5-7
Discription
read reference position
about 0.5 mm from the reference position to the inner side
of the roller
about 1.0 mm from the reference position to the inner side
of the roller