Konica Minolta BIZHUB 25E Field Engineering Manual page 236

4.5.11 Uneven image density
Scanner section
Section Step Check item
Scanner section 1
2
3
4
5
Printer section
Section Step Check item
Drum cartridge 1
2
3
4
Fuser unit 5
Transfer section 6
7
Discharge plate 8
Circuit boards 9
10
Are the ADF glass and document
glass dirty?
Is the shading-sheet located under
the size cover dirty?
Is the CIS (lens and lamp) dirty or
deteriorated?
Do the connection from CIS to main
control board remain intact?
Is the trouble settled with above
steps?
Is the drum cartridge driven properly?
Is the OPC drum dirty or damaged?
Are the developing bias, supply bias
and blade bias contact terminal dirty
or deformed?
Are the grid bias, charge bias and
drum ground contact terminal dirty or
deformed?
Are the fusing rollers or separation
scraper dirty or damaged?
Is the transfer bias contact terminal
dirty or deformed?
Is the transfer roller dented or dam-
aged?
Is the discharge plate deformed?
Are the connections from LED print
head and from high-voltage board to
main control board in good condition?
(Check plugs firmly plugged and
snapped harness.)
Is the trouble settled with above
steps?
Result Remedy
Yes Clean
Yes Clean or replace CIS, and ad-
just the background level
Yes Clean or replace CIS, and ad-
just the background level
No Reconnect / Replace harness.
No 1. Adjust the background level.
2. Replace CIS.
3. Replace main control board.
Result Remedy
No Correct / Replace drive cou-
pling mechanism of drum
cartridge and machine.
Replace the drum cartridge.
Yes Replace OPC drum
Yes Clean / Repair
Yes Clean / Repair
Yes Clean / Replace
Yes Clean / Repair
Yes Replace
Yes Replace
No Reconnect / Replace harness
No 1. Replace drum cartridge.
2. Replace fuser unit.
3. Replace LED print head.
4. Replace main control board.
5. Replace high-voltage power
board.
6. Replace transfer roller unit.
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