Dirt Sensor Control; Stream Reading Dust Detection Control - Canon imagerunner C5180 Service Manual

6.3.5 Dirt Sensor Control

6.3.5.1 Stream Reading Dust Detection Control

The machine checks the stream reading glass and the ADF platen roller for the presence/absent of dust. It then
changes the point of reading or executes image correction depending on the result of detection, thereby avoiding
reproduction of dust particles in its output images. The machine executes the detection mechanism only when
the ADF is used:
1. Timing of Detection
(1) at the end of a job
(2) between sheets (for every sheet read)
Start key
ON
*Executed only if dust has been detected at all points, i.e., A, B, C, D, and E in the previous job. If so, the
machine uses the point with least dust as the reading position and executes dust correction before starting
reading operation.
2. Particulars of Control
(1) at the end of a job (makes a change to the point of stream reading dust reading position)
The machine checks the light reflected by the platen roller at the reading position to see if there is dust,
moving to the next point if it finds dust (from A to B, C, D, and then to E; 5 points max.). It uses the first
point that is free of dust as the reading point for the next job.
1st
SCAN
Dust detection* Dust detection
2nd
SCAN
Dust detection
F-6-27
Chapter 6
6-17