Brother HL-7050 Service Manual page 249

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 cassette.
(2) Turn off the power switch of the printer.
(3) While holding down the Go switch, press – switch, + switch, and then Set switch. The
LCD display shows "TEST MENU".
(4) Press the Set switch and "SINGLE TEST PRINT" will appear on the LCD display.
(5) Press the + switch and "REPEAT TEST PRINT" will appear on the LCD display.
(6) Press the Set switch and "TEST PRINT NORMAL" will appear on the LCD display.
(7) Press the + switch four times and "TEST PRINT WHITE" will appear on the LCD display.
(8) Press the Set switch and release it immediately. A blank page is printed while cleaning
the pressure roller.
(9) Press the Job Cancel switch after printing three or more pages to stop printing.
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?
6-39
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.
HL-7050 SERVICE MANUAL