Please check the following points to solve the problem:

• (For models with Automatic Document Feeder only)
  Wipe the scanner glass strip with a dry lint free soft cloth.
   
• Clean the primary corona wire inside the drum unit by sliding the green tab.
  Please refer to the instructions, "Clean the corona wire of the drum unit.".
   
• Make sure the green tab of the primary corona wire is at the home position ().
   
• The drum unit may be damaged. Put in a new drum unit.
  Please refer to the instructions, "REPLACE DRUM".
   
• The toner cartridge may be damaged. Put in a new toner cartridge.
  Please refer to the instructions, "REPLACE TONER".
   
• The fuser unit may be contaminated. Call your dealer or Brother Customer Service.