Brother HL-1070 Service Manual page 74

I-6
Possible cause
Corona failure
Corona failure
Dirt in the paper
feed system
Scratch on the
drum
Cleaning failure
Scratch on the
heat roller
Note:
I-7
Possible cause
Scratch on the
drum
Toner stuck on
the developer
roller
Scratch on the
fixing roller
SR PCB
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Black vertical streaks
Step
1 Is the corona wire dirty?
2 Is the vertical block streak
about 10mm wide?
Is the corona wire cleaner not
in its home position?
3 Is the paper tray or feed
system on the drum unit soiled
with toner?
4 Is the drum surface scratched?
5 Is the drum surface dirty with
toner in streaks?
6 Is the surface of the heat roller
scratched?
Is you print the same pattern continuously, the drum will be worn away and
black vertical streaks appear on the paper.
Black and blurred horizontal stripes
Step
1 Are the horizontal stripes at
94mm (OPC drum) intervals?
2 Are the horizontal stripes at
25mm (developer roller)
intervals?
3 Are the horizontal streaks at
63mm (heat roller) intervals?
4 Is the problem solved after the
SR PCB replaced?
Black and blurred vertical streaks
Check Result
Yes
Yes
Yes
Yes
Yes
Yes
Check Result
Yes
Yes
Yes
Yes
IV-10
Remedy
Clean the corona
wire with the wire
cleaner.
Return the wire
cleaner to its home
position.
Clean the toner off.
Replace the drum
unit.
Replace the drum
unit.
Replace the fixing
unit.
Remedy
Replace the drum unit.
Print several sheet and see
what happens.
The problem will disappear
after a while. If not, replace the
drum unit.
Replace the fixing unit.
Replace the SR PCB.
HV.GND
contacts
(Fig.4-5)