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

roller, 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)

[Description of Control]

- At job end (Dust detection)

The contact image sensor (CIF) checks the light reflected by the ADF platen roller 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.

- At job start (Dust bypass)

Presence/absence of dust is detected at all points A, B, and C in this order at job end. The original is read at the point where least dust is detected.

4-10

AB-Configration

Original

size

sensor 1

sensor 3

sensor 2

B4(8K)*1

B5(16K)*1

A4R

B5R(16K)*1

No original