Brother mfc8440 Service Manual page 247
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Also See for mfc8440:
- User manual (426 pages) ,
- Software user's manual (183 pages) ,
- Quick setup manual (52 pages)
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CHAPTER 6 TROUBLESHOOTING
I-6
Black and blurred vertical streaks
Possible cause
Dirt on the
scanner glass.
Dirt on the CCD.
Corona failure
Dirt in the paper
feed system
Scratch on the
drum
Cleaning failure
Scratch on the
heat roller
NOTE:
• If you print the same pattern (especially vertical streaks) continuously, electrostatic charge
performance of the drum will decrease temporarily and black vertical streaks may appear
on the paper.
• This problem may occur with noise due to the corona wire being dirty. In that case, clean
the corona wire with the wire cleaner.
User Check
(1) Clean the corona wire in the drum unit.
(2) Check that the corona wire cleaner is at the home position.
(3) Check that the toner cartridge is not empty.
(4) The drum unit may be damaged. Install a new drum unit.
(5) The toner cartridge may be damaged. Install a new toner cartridge.
Step
Check
Is there any dirt on that?
1
Is there any dirt on that?
2
3
Is the vertical block streak
about 10mm wide?
(Check if the wire cleaner is at
its home position.)
4
Is the paper tray or feed
system on the drum unit dirty
with toner?
5
Is the drum surface scratched?
6
Is the drum surface dirty with
toner in streaks?
7
Is the surface of the heat roller
scratched?
Result
Yes
Clean the scanner glass.
Yes
Replace the CCD.
Yes
Return the wire cleaner to its
home position.
Yes
Clean the toner off.
Yes
Replace the drum unit.
Yes
Replace the drum unit.
Yes
Replace the fixing unit.
6-40
Remedy
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Troubleshooting
