Please check the following points to solve the problem:

1. Check the machine's environment. Conditions such as high humidity and high temperatures may cause this print quality problem.
   
   
2. The drum unit or toner cartridges may not be installed correctly. Re-install the drum unit and toner cartridges.
   
   
   • Click here to see the details of how to install the drum unit.
   • Click here to see the details of how to install the toner cartridges.
     
     
3. Clean the drum unit. Click here to see the details of how to clean the drum unit.
   
   
4. Update your Brother machine's firmware to the latest version.
   Click here to download and install the Firmware Update Tool, and update your machine's firmware.
   
   
5. The toner cartridge may be damaged. Put in a new toner cartridge as follow:
   
   
   1. Click here to print the chart. [345KB/ PDF]
   2. Compare your printed document with the printed chart to identify the color causing the problem.
   3. Replace the toner cartridge of the color. Click here to see the details of how to replace the toner cartridge.
      
      
6. The drum unit may be damaged. Put in a new drum unit. Click here to see the details of how to replace the drum unit.