Brother HL 5030 - B/W Laser Printer Service Manual page 209

I-5 Dirt on the back of paper
Possible cause Step
Fixing unit dirty 1
Dirt in the drum 2
unit
NOTE:
This problem may disappear after printing approximately 10 pages of completely blank sheets.
How to clean the pressure roller
Clean the pressure roller as follows;
(1) Set three or more sheets of paper in the paper tray.
(2) Open the front cover, and turn on the power switch while holding down the Go button.
(3) Release the panel button when the Toner LED is on.
(4) Close the front cover.
(5) Hold down the panel button until the Drum LED is on, then release the button. Cross
stripes are printed.
(6) Print approximately 5 pages then press the Job Cancel button.
(7) Make sure that the dirt on the back of paper has disappeared.
Check
Is the pressure roller dirty?
Is any other area in the printer
dirty?
Is the transfer roller dirty?
Is the problem solved after
replacing the drum unit?
6-29
HL-5030/5040/5050/5070N SERVICE MANUAL
Result Remedy
Clean the pressure roller
Yes
referring to the following
procedure.
Yes Replace the drum unit
No Replace the high-voltage power
supply PCB.