U091 Checking Shading - Kyocera KM-3035 Service Manual

Maintenance
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. The screen for selecting an item is displayed.
2. Select the item to be operated. The selected item is displayed in reverse.
Display
SHD BEFORE
SHD AFTER
3. Press the start key. Scanning is performed under the selected conditions and the result is displayed.
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 assumed to be 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.
4. To return to the screen for selecting an item, press the stop/clear key.
Completion
Press the stop/clear key at the screen for selecting an item. The screen for entering a maintenance item is
displayed.
Description
Performs scanning before shading and displays the result.
Performs scanning after shading and displays the result.
20 mm from the machine left
200 mm from the machine left
400 mm from the machine left
100 mm from the
machine center
toward machine
front
Description
Machine center
Figure 1-4-4
2FD/2FF/2FG
100 mm from the
machine center
toward machine
rear
1-4-31