Please check the following points to solve the problem:

• Make sure that you use paper that meets our specifications. Rough-surfaced paper may cause the problem.
  Please refer to the FAQs "What kind of paper can I use?" and "What is the recommended paper?"
  
  
• Clean the corona wire and the drum unit.
  Please refer to the FAQs  "Clean the corona wire." and "Clean the drum unit."
  
  
• The drum unit may be damaged.
  Put in a new drum unit. Please refer to the FAQ "REPLACE DRUM".
  
  
• The fuser unit may be contaminated. Please contact Brother Customer Service from "Contact Us"