SCANNER UNIT August, 2006
6-36
6.5.5 DUST DETECTION
Overview
When an original is put on the original feed table of the A RDF, the ARDF exposure
glass is checked for dust.
The dust check is done before the first original is scanned. This is done only once
at the beginning of a job. The check is not done for originals added during a long
scanning job.
The ARDF transport belt turns with no paper fed across the ARDF scanning glass.
The surface (white) of the ARDF transport belt is scanned. The IPU checks if dust
is present.
• If dust is detected, the scanner carriage position for ARDF scanning is moved by
0.7 mm.
• The next time that dust is detected, the scanning position is moved again by 0.7
mm.
• The third time that dust is detected, the scanning position is not moved. An alert
message is displayed but the job does not stop.
• Then, at the start of the next job, the procedure starts again, but the scanner
does not go back to home position.
Start
Do dust detection?
SP4020 001 ON
SP4020 001 OFF
Dust Check Processing
NO
YES
Dust detected? NO
YES
3 turnovers?
NO
YES
Scan Position Movement
Processing
Alert
display
Copying
No alert
display
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