Brother HL-1070 - B/W Laser Printer Service Manual page 73

I-5 Dirt on the back of paper
Possible cause Step
Fixing unit 1
Dirt in the drum 2
unit
Note: Cleaning of the pressure roller
(1) Set three or more sheets of paper in MP sheet feeder 1 (or 2).
2)
(3) Turn on the power switch while holding down the switch on the control
(4) Release the panel switch when the Drum lamp is on.
(5) Close the top cover.
(6) Hold down the panel switch until the Ready lamp is on, and then release
(7)
(8)
(9)
(10) Turn on the power switch while holding down the switch on the control
(11) Release the panel switch when the Drum lamp is on.
(12) Press the panel switch again and release it immediately.
(13) Print a page of test pattern while cleaning the pressure roller.
Check
Is the pressure roller dirty?
Is any other area in the printer
dirty?
Is the transfer roller dirty?
is the problem solved after the
drum unit replaced?
Open the top cover.
panel.
the switch.
Print three patterns; grid, zip and solid black.
Turn off the power switch with the top cover closed.
Set paper in the manual slot with the solid black side up.
panel.
Result
Yes
Yes
No
IV-9
Remedy
Clean the pressure roller.
(See the following note.)
Replace the drum unit
Replace the H.V. power supply
PCB.