Konica Minolta bizhub 25e, Field Engineering Manual

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4-30
4.5.11 Uneven image density
Scanner section
Section Step Check item Result Remedy
Scanner section 1 Are the ADF glass and document
glass dirty?
Yes Clean
2 Is the shading-sheet located under
the size cover dirty?
Yes Clean or replace CIS, and ad-
just the background level
3 Is the CIS (lens and lamp) dirty or
deteriorated?
Yes Clean or replace CIS, and ad-
just the background level
4 Do the connection from CIS to main
control board remain intact?
No Reconnect / Replace harness.
5 Is the trouble settled with above
steps?
No 1. Adjust the background level.
2. Replace CIS.
3. Replace main control board.
Printer section
Section Step Check item Result Remedy
Drum cartridge 1 Is the drum cartridge driven properly? No Correct / Replace drive cou-
pling mechanism of drum
cartridge and machine.
Replace the drum cartridge.
2 Is the OPC drum dirty or damaged? Yes Replace OPC drum
3 Are the developing bias, supply bias
and blade bias contact terminal dirty
or deformed?
Yes Clean / Repair
4 Are the grid bias, charge bias and
drum ground contact terminal dirty or
deformed?
Yes Clean / Repair
Fuser unit 5 Are the fusing rollers or separation
scraper dirty or damaged?
Yes Clean / Replace
Transfer section 6 Is the transfer bias contact terminal
dirty or deformed?
Yes Clean / Repair
7 Is the transfer roller dented or dam-
aged?
Yes Replace
Discharge plate 8 Is the discharge plate deformed? Yes Replace
Circuit boards 9 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.)
No Reconnect / Replace harness
10 Is the trouble settled with above
steps?
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.