143
Troubleshooting 
 
Black lines down the page
Printed pages have toner stains 
down the page
 Clean the corona wire inside the drum unit by sliding the green tab.
uu Cleaning the corona wire uu page 110
 Make sure the green tab of the corona wire is at the home position (a).
 The toner cartridge may be damaged. Put in a new toner cartridge.
uu Replacing the toner cartridge uu page 95
 The drum unit may be damaged. Put in a new drum unit.
uu Replacing the drum unit uu page 103
 The fuser unit may be contaminated. Call your Brother customer service for 
support.
 
White lines down the page
 Make sure that foreign material such as a torn piece of paper, sticky notes or 
dust is not inside the machine and around the drum unit and toner cartridge.
 The toner cartridge may be damaged. Put in a new toner cartridge.
uu Replacing the toner cartridge uu page 95
 The drum unit may be damaged. Put in a new drum unit.
uu Replacing the drum unit uu page 103
 
Image skewed
 Make sure that the paper or other print media is loaded correctly in the paper 
tray and that the guides are not too tight or too loose against the paper stack.
 Set the paper guides correctly.
uu Printing on plain paper, thin paper or recycled paper from Tray 1 and 
Tray 2 uu page 9
 If you are using the MP tray, see Printing on plain paper, thin paper, recycled 
paper and bond paper from the MP tray uu page 12.
 The paper tray may be too full.
uu Loading paper and print media uu page 9
 Check the paper type and quality.
uu Acceptable paper and other print media uu page 2
 Check for loose objects such as torn paper inside the machine.
 If the problem only occurs during duplex printing, check for torn paper in the 
duplex tray, verify that the duplex tray is inserted completely and verify that 
the back cover is closed completely.
Examples of poor print quality Recommendation
ABCDEFGH
abcdefghijk
ABCD
abcde
01234
ABCDEFGH
abcdefghijk
ABCD
abcde
01234
ABCDEFGH
abcdefghijk
ABCD
abcde
01234