2C9
1-4-19
Maintenance
Description
item No.
U091 Checking shading
Description
Performs scanning under the same conditions as before and after shading is performed, displaying the original
scanning values at nine points of the contact glass.
Purpose
To check the change in original scanning values before and after shading. The results may be used to decide
the causes for fixing unevenness (uneven density) of the gray area of an image: either due to optical (shading
or CCD) or other problems.
Also to check the causes for a white or black line appearing longitudinally.
Method
1. Press the start key. A selection item appears.
2. Select the item to be operated using the zoom +/– keys.
Display Operation
on Performs scanning before shading and displays the result.
oFF Performs scanning after shading and displays the result.
3. Press the start key. Scanning is performed under the selected conditions and the result is displayed.
4. Change the measurement point by lighting a copy exposure indicator or making one flash using the copy
exposure adjustment keys. For the correspondence between the measurement points and the copy
exposure indicators, see Figure 1-4-4.
Figure 1-4-4
When scanning is performed before shading, the scan value at the machine center should be slightly
different from those at the machine front and rear. When scanning is performed after shading, there should
be no difference between respective values. Any differences between the values at machine front and rear
indicates that scanner problem causes the fixing unevenness.
If the displayed results indicate no shading problems, the fixing unevenness (uneven copy density) is
caused by factors other than in the scanner section (shading or CCD).
If a black line appears, the cause may be assumed based on the results of the scanning operation before
shading: if a white line appears, they may be assumed based on the results of the scanning operation after
shading. Note that depending on the thickness and location of the black or white line, it may not be possible
to use this method to determine the cause. This is because the displayed values obtained from scanning at
the limit of nine points are insufficient to provide significant information.
5. Press the stop/clear key. The selected item appears.
Completion
Press the stop/clear key while a selection item is displayed. The indication for selecting a maintenance item No.
appears.
100 mm from the machine
center toward machine rear
Machine center
100 mm from the machine
center toward machine front
200 mm from
machine left
20 mm from the machine left
400 mm from machine left
123
456
789
Point Copy exposure indicator
1 exp. 1 (lit)
2 exp. 2 (lit)
3 exp. 3 (lit)
4 exp. 4 (lit)
5 exp. 5 (lit)
Point Copy exposure indicator
6 exp. 1 (flashing)
7 exp. 2 (flashing)
8 exp. 3 (flashing)
9 exp. 4 (flashing)
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