Canon ImageRunner iR8500 Series, Servise Manual

Page: 63 / 655

CHAPTER 2 NEW FUNCTIONS
2-19
COPYRIGHT© 2001 CANON INC. 2000 2000 2000 2000 CANON iR8500 REV.0 MAR. 2001
2.2.4 CCD Adjustment
The CCD is made up of two CCDs joined in the middle; as such, if the gain characteris-
tics differ between its first half and its last half, the image read at the seam will be different,
causing a line in the image.
If the reader controller PCB or the CCD/AP PCB has been replaced or the CCD correc-
tion data stored in the SRAM of the reader controller PCB is lost, you must execute CCD
adjustment in service mode, thereby equalizing the gain at the joint between the first half
and the last half.
The new parameters occurring after adjustment will all be stored in the SRAM of the
reader controller PCB.
Adjustments may be any of the following three in service mode:
A. CCD Shading Correction
COPIER>FUNCTION>CCD>CCD-ADJ
By executing CCD shading correction (as in the GP605 (iR600))
B. CCD Gain Simple Correction
COPIER>FUNCTION>CCD>LUT-ADJ
By executing automatic CCD gain correction using white paper
C. CCD Gain Full Correction
CCD>FUNCTION>CCD>LUT-ADJ2
By using a 10-gradation chart (if CCD simple correction fails)
One of the above needs to be selected to suit the conditions in question.
After executing A, be sure to execute B; if adjustment still fails, execute C.
Do not execute B or C alone.
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