Canon F-1, Service Manual

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Technology > Controls > Reader > Dust detection control
Technology > Controls > Reader > Dust detection control
● Dust detection correction control (non-continuous lines)
The machine detects and corrects the lines due to the dust other than dust between sheets.
The dust on the original is not detected before the leading edge of original. This dust sometimes stops at the reading position due to the friction with the reading glass and sticks to the original again.
In this case, the dust is fed together with the original and will not be detected after the trailing edge of the original. This control detects the non-continuous lines appears between the leading edge and
the training edge formed as above and corrects the image.
This correction targets the lines in the sub scanning direction on the read image. The machine determines whether the lines are due to the dust or not by the length, color and brightness of lines and
the correction is executed if the lines are deemed as dust-related lines.
Also, if the dust causing lines exceeds the specified amount, the machine displays an alarm to prompt cleaning.
Before reading After reading Result of reading
Stream reading
glass
Floating dust
Scanning position
Platen roller 1
Original
It sticks on the original
during scanning.
Note:Additional function mode (removing the faulty lines)
At the original reading, you can specify whether to execute the removing function or not
when non-continuous lines are detected.
Setting items are as below.
• ON: Detect and remove the non-continuous lines (default).
• OFF: Do not remove the non-continuous lines.
When there are extra-fine lines on the original, if this item is set to ON, the machine
sometimes detects them as non-continuous lines erroneously and they may be
removed from the image. If the extra-fine lines on the original are removed frequently
due to wrong detection, specify this item to OFF.
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