Shading Correction; Parts Replacement Procedure; Copyboard Glass; Removing The Copyboard Glass - Canon iR3570 Service Manual

5.3.6.7 Shading Correction

iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N /
/ iR4570N / iR2230 / / / iR3530 /
The machine executes this correction for every scan made in main shading
unit. It measures the density of the standard white plate, and compares the
result against the target value stored in the shading correction circuit; the dif-
ference between the two will be held as the shading correction value for use
in correcting variation among CCD pixels when scanning the original, thus
evening out the density levels of the image.
CCD output
Target value
Measurement
F-5-28

5.4 Parts Replacement Procedure

5.4.1 Copyboard glass

5.4.1.1 Removing the Copyboard Glass

iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N /
/ iR4570N / iR2230 / / / iR3530 /
1) Open the copyboard cover (or ADF).
2) Remove the 2 screws [1], and detach the glass retainer [2]; then, detach
the copyboard glass [3].
F-5-29
When removing the copyboard glass, take care not to touch the following:
- glass surface
- standard white plate
The presence of dirt can cause white/black lines in the images. If dirt is
found, clean it with lint-free paper moistened with alcohol.
Characteristics after co
Characteristics before
White
Original density
Standard white plate
0006-5938
0006-9714
F-5-30

5.4.1.2 Removing the ADF Reading Glass

iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N /
/ iR4570N / iR2230 / / / iR3530 /
1) Open the copyboard glass (or ADF).
2) Remove the 2 screws [1], and detach the glass retainer [2].
3) Remove the ADF reading glass [3].
F-5-31
When removing the ADF reading glass, take care not to touch the glass sur-
face.The presence of dirt can cause white/black lines in the images. If dirt is
found, be sure to clean it using lint-free paper moistened with alcohol.

5.4.2 Reader Controller PCB

5.4.2.1 Before Replacing the Reader Controller PCB

iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N /
Chapter 5
0006-9730
0007-0740
5-15