Brother MFC-8440 B - Manual (Page 193)

TROUBLESHOOTING AND ROUTINE MAINTENANCE 12 - 32
5
Remove the protective cover.
6
Insert the new toner cartridge in the drum unit until it clicks into
place. If you put it in properly, the lock lever will lift automatically.
7
Clean the primary corona wire inside the drum unit by gently
sliding the blue tab from right to left several times. Return the
blue tab to the Home position (
▼) before reinstalling the drum
unit and toner cartridge assembly.
Toner Cartridge
Drum Unit
Corona Wire
Tab
Home Position(
▼)