Canon iR4570 Series Service Manual page 228

Chapter 5
Start key
Main power switch
ON
STBY
WMUPR
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
5-20
ON
1st
SCAN
Dust detection control
Dust detection control
B C
2nd
SCAN
Dust detection control