Canon Color iR C3480 Service Manual page 128

Chapter 2
5) Adjust the DADF angle by right-side hinge adjustment screw [1].
Loosen the fixing nut [2] before adjustment. Tighten it after adjustment.
* For A > B => Rotate clockwise.
* For A < B => Rotate counterclockwise.
F-2-167
6) Tighten all of the hinge fixing screw loosened in the step 3).
5. Reading Position Adjustment
1) Select the screen from the service mode screen in the following order, to
display the adjustment screen.
COPIER > FUNCTION > INSTALL
2) Press STRD-POS (highlighted).
3) Press OK key.
The scanner starts scanning by pressing OK. Auto adjustment of scanning
position is completed in a few seconds, OK is displayed.
If auto adjustment is failed and NG is displayed, perform the following
steps.
1. Clean the white roller of DADF and the copyboard glass of the main unit,
and perform auto adjustment again.
2. If it fails again, perform manual adjustment in the following step by the
service mode.
COPYER > ADJUST > ADJ-XY > STRD-POS
The default is 30.
Modify the value and check the actual copy image, and determine the
optimum value.
6. Reproduction Ratio Adjustment
2-46
MEMO:
DADF reproduction ratio adjustment is performed by comparing the stream
reading copy image and pressing plate reading copy image (because the
DADF is for color machine). Comparison between stream reading copy
image and original is performed at DADF for the previous monochrome
machine, so perform adjustment taking this difference into account. When
reproduction ratio adjustment by comparing stream reading copy image and
original is performed as in the case of monochrome DADF, the following
problems may occur.
- ACS erroneous decision
- Black text enhancement erroneous decision
1) Set test chart to DADF, copy one set. This is to be copy B.
2) Set the test chart used in the step 1) to the copyboard glass of the main unit,
copy one sheet. This is to be copy A.
3) Compare the image length in the feeding direction between copy A and
copy B. Perform adjustment at the service mode if necessary.
FEEDER > ADJUST > LA-SPEED (highlighted)
Copy B image is short => Decrease the value (Make the document stream
reading speed lower)
Copy B image is long => Increase the value (Make the document stream
reading speed higher)
Adjustment value unit 1=0.1mm
7. Horizontal Registration Adjustment
1) Set the test chart to DADF, copy one set.
2) Compare the test chart and the copy paper horizontal registration. Perform
adjustment at the service mode if necessary.
COPIER > ADJUST > ADJ-XY > ADJ-Y-DF
Image is displaced to the front side => Decrease the value
Image is displaced to the rear side => Increase the value
Adjustment value unit 1=0.1mm
8. Rear End Registration Adjustment
1) Set the test chart to DADF, copy one set.
2) Compare the test chart and the copy paper rear end registration. Perform
adjustment at the service mode if necessary.
FEEDER > ADJUST > DOCST
Image is displaced to the front side => Decrease the value
Image is displaced to the rear side => Increase the value
Adjustment value unit 1=0.1mm
9. White Level Adjustment
MEMO:
This is the adjustment to adjust the white level of the stream reading image
to the white level of the pressing plate reading image (because DADF is for
color). If this adjustment is not performed, the following problems may
occur.
- Incorrect under-color density of the stream reading image
- Wrong detection of solid in the stream reading mode
1) Set paper (for user normal use) on the copyboard glass, close DADF.
2) Select the screen from the service mode screen in the following order, to
display the adjustment screen.
COPIER > FUNCTION > CCD
3) Press DF-WLVL1 (highlighted).
4) Press OK key.
Auto adjustment is performed. When it is correctly completed, 'OK!' is