Canon imageRunner 2022, Service Manual

Page: 160 / 418

Chapter 4
4-14
4.3.5 Dirt Sensor Control
4.3.5.1 Outline
0017-2635
iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018i
The machine changes the original read position or corrects the read image depending on the presence/absence of dust on the stream reading glass or ADF platen
roller, thus preventing dust from showing up in the image. This control is performed only when the ADF is used and it is closed.
[Control Timing]
- At job end
- Immediately before scanning (one sheet at a time)
F-4-26
[Description of Control]
- At job end (Dust detection)
The contact image sensor (CIS) checks the light reflected by the ADF platen roller surface at the read position for presence/absence of dust. After completion of a
job, dust detection is performed maximum six times in 3 point of A, B and C. First, dust detection is performed once at position A. If no dust is detected at position
A, dust detection is performed twice there. If no dust is detected, the original is scanned at position A. If dust is detected at position A, move to position B and dust
detection is performed twice at position B. If no dust is detected at position B, the original is scanned at position B. If dust is also detected at position B, move to
position C and dust detection is performed once at position C. If dust is also detected at position C, a relevant message is displayed on the operation panel. In this
case, move back to position A and the original is scanned at position A.
F-4-27
- Immediately before scanning (one sheet at a time)
The contact image sensor (CIS) does not move to detect dust.
The original is read at the position determined at job end or start. If presence of dust is detected there, the read image is corrected.
- At job start (Dust bypass)
Presence/absence of dust is detected at all points A, B, and C in this order at job end. The original is read at the point where least dust is detected.
Main power
switch
ON
Dust detection control
Dust detection control
STBY WMUPR
Start key
ON
1st
SCAN 2nd
SCAN
Dust detection control
A
B C