Canon iR C2880 series, Руководство по обслуживанию

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Chapter 5
5-13
F-5-24
F-5-25
5.3.6 Dirt Sensor Control
5.3.6.1 Overview
0013-8592
/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
When reading an original, the machine changes the point of reading or corrects image data in reference to the presence/absence of dust on the stream reading glass/
ADF platen roller, thereby avoiding the effects of dust on images. The machine executes this control only when the ADF is used and, in addition, when it is closed.
1. Timing of Control
(1) at the end of a job
(2) between sheets (each time a sheet is read)
(3) at the start of a job (only if any of the following is met)
(a) first job after power-on
(b) presence of dust at all points of detection at the end of the previous job
(c) failure of dust detection at the end of the previous job (e.g., the ADF is opened)
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2. Particulars of Control
(1) At the End of a Job (dust detection)
The contact image sensor (CIS) checks the light reflected by the platen roller of the ADF at a point of reading to find out the presence/absence of dust. If the
presence of dust is detected, the contact image sensor moves to the next candidate point (2 times max.; A -> B -> C; B -> C -> A; or C -> A -> B).
The point identified will be used as the point of reading for the next job.
- For the control at the end of a job, the sensor will never move to point D.
- For the control at the end of a job, a message prompting cleaning of the glass surface will be indicated if an original is placed in the ADF while the presence of
dust has been detected at all points (A, B, C). The Start key is disabled until the message is cleared.
(2) At the Start of a Job (dust avoidance)
The same detection mechanism as used at the end of a job is executed; if the presence of dust is detected at all points (A, B, C), the sensor is moved to point D
for reading operation.
If the control is at the end of a job that takes place at point D, it will be after moving the sensor to point D.
CIS HP
Copyboard glass
AB-Configuration
A3
A4
B4
B5
A4R
A5
B5R
No original
Original
size
1 2 3 4
Original
sensor1
Inch-Configuration
11"X17"
LTR
LGL
LTR-R
STMT-R
No original
Original
size
1 2 3
Original
sensor2
: Change absent
: Change present
Main power
switch
ON
Dust detection control
Dust detection control
Dust detection control
STBY WMUPR
Start key
ON
1st
SCAN 2nd
SCAN