Konica Minolta bizhub 25e, Field Engineering Manual

Page: 229 / 353

4-23
4.5.4 Low image density / rough image
Scanner section
Section Step Check item Result Remedy
Scanner section 1 Do the connection from CIS to main
control board remain intact?
No Reconnect / Replace harness.
2 Are the document glass, document
pad and ADF glass dirty?
Yes Clean
3 Is the CIS lens dirty? Yes Clean, or replace the part and
adjust the background level
4 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
Paper 1 Is the paper damp? Yes Replace the paper.
LED print head 2 Is the lens dirty? Yes Clean
Drum cartridge 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
Transfer section 5 Is the transfer bias contact terminal
dirty or deformed?
Yes Clean / Replace
6 Is the transfer roller gap dirty? Yes Clean / Replace
Circuit boards 7 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
Toner sensor er-
ror
8 Is the toner sensor working?
(Use “3.20 Sensor input test” on page
3-98 and check that the sensor is
working.)
No Reconnect / Replace sensor
9 Is the trouble settled with above
steps?
No 1. Replace drum cartridge.
2. Replace LED print head.
3. Replace main control board.
4. Replace high-voltage power
board.
5. Replace transfer roller unit.