Brother HL-5240 Service Manual page 170

CHAPTER 4 TROUBLESHOOTING
(I-24) Toner specks
User Check
(1) Check the paper used meets the recommended paper specifications. A rough
surfaced paper may cause the problem.
(2) The toner cartridge may be damaged. Install a new toner cartridge.
(3) The drum unit may be damaged, or may be nearly at the end of life. Install a new
drum unit.
4-56 Confidential