Please check the following points to solve the problem.
NOTE: The illustration shown below is from a representative product, and may differ from your Brother machine.

1. Check the machine's environment. Conditions such as high humidity and high temperatures may cause this print quality problem.
   
   
2. Check that you use the paper that meets our specifications. Click here to see the details of the recommended paper.
   
   
3. Make sure that the media type settings in the printer driver and in the machine's Paper Type menu match the type of paper you are using.
   
   
4. Make sure that the two gray levers inside the back cover, one on the left-hand side and one on the right-hand side, are in the up position.
   
   
   
   
5. 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.
     
     
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.