Brother HL-1020 Service Manual page 76

I-5 Dirt on the back of paper
Possible cause Step
Fixing unit 1
Dirt in the drum 2
unit
Note: Clean the pressure roller as follows;
(1) Set three or more sheets of paper in the MP sheet feeder.
(2) Open the top cover.
(3) Turn on the power switch while holding down the switch on the control panel.
(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, then release the
switch.
(7) Print three patterns; grid, zip and solid black.
(8) Turn off the power switch with the top cover closed.
(9) Set paper in the manual slot with the solid black side up.
(10) Turn on the power switch while holding down the switch on the control panel.
(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 is replaced?
IV-9
Result Remedy
Yes Clean the pressure roller.
(See the following note.)
Yes Replace the drum unit
No Replace the high-voltage
power supply PCB.