Canon F-1, Service Manual

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Technology > Controls > DADF > Original Scanning Assembly
Technology > Controls > DADF > Original Scanning Assembly
Scanning glass dust detection control
In the case of 2-side scanning with this equipment, dust and smudges on the scanning glass
(attached when scanning the back side) can cause lines on the image.
To prevent this symptom, there is a dust detection correcting function with this equipment.
This function makes the reader controller to shift the scanning glass to the scanning position
at detection timing for detecting the degree of smudges on scanning surface.
In the case of smudges detected at the scanning position, the scanner unit is shifted to
smudge-free position to prevent image fault.
There are 3 scanning positions to be detected in the order as shown below. If there is smudge
at the first position, the scanning position is shifted to the next scanning position to execute
scanning of the backside.
If smudge is detected at all 3 scanning positions, a user message is displayed to encourage
cleaning of the scanning glass (DF operation is available when this message is shown).
[1] Glass shift home position detection signal
[2] Glass shift motor drive signal
[3] Scanning glass
[4] Standard white plate
[5] Scanner unit
[6] Home position
[7] Scanning position ([A], [B], [C])
M9 Glass shift motor
Service Mode
(Lv.1) COPIER > OPTION > IMG-RDR > DF2DSTL1
Adj:Dust detct lvl at DADF STintrvl:Back
(Lv.1) COPIER > OPTION > IMG-RDR > DF2DSTL2
Adj:Dust detect lvl at DADF job end:Back
M9
DADF driver PCB
[3] [4]
[5]
[4]
[3]
[7] [6]
[A] [C] [B]
0.5 mm 0.5 mm
14.5 mm
SR11
[2]
[1]
Scanning position
F-2-71