Ccd Adjustment - Canon iR8500 Service Manual

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CHAPTER 2 NEW FUNCTIONS

4.4 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

B. CCD Gain Simple Correction

C. CCD Gain Full Correction

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.

COPIER>FUNCTION>CCD>CCD-ADJ

By executing CCD shading correction (as in the GP605)

COPIER>FUNCTION>CCD>LUT-ADJ

By executing automatic CCD gain correction using white paper

CCD>FUNCTION>CCD>LUT-ADJ2

By using a 10-gradation chart (if CCD simple correction fails)

2000 2000 2000 2000

CANON iR8500/7200 REV.1 AUG. 2001

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