Canon iR1020 Series, Service Manual

Page: 83 / 304

Chapter 4
4-5
4.3.2 Dirt Sensor Control
4.3.2.1 Outline
0013-1096
iR1020J / iR1024J / iR1020 / iR1024 / iR1024A / iR1024N / iR1024F / iR1024i / iR1024iF
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
guide, 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-4-8
[Description of Control]
- At job end (Dust detection)
The contact sensor (CS) checks the light reflected by the ADF platen guide surface at the read position for presence/absence of dust. After completion of a job, dust
detection is performed three times. 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.
If presence of dust is detected at all points A, B, and C in this order at job end, the machine will indicate a reading glass cleaning message in the control panel.
F-4-9
- 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.
Main power
switch
ON
Dust detection control
Dust detection control
STBY WAIT
Start key
ON
1st
SCAN 2nd
SCAN
Dust detection control
Reading glass
lens
LED
Contact sensor
Platen guide
0.5mm 0.5mm
A B C