Vertical black lines appear on the printout. : Brother

Date:04/26/2013 ID:faq000006_011

Title:
Vertical black lines appear on the printout.

Please check the following points:

Clean the primary corona wire inside the drum unit. To see how to clean the corona wire of the drum unit, click here.
Make sure the primary corona wire cleaner is at the home position.
The toner cartridge may be damaged. Put in a new toner cartridge. To see how to replace the toner cartridge, click here.
The drum unit may be damaged. Put in a new drum unit. To see how to replace the drum unit, click here.
The fuser unit may be smudged. Call your dealer or Brother Customer Service.