Brother HL-4200CN - Manual (Page 130)

7 - 4 ROUTINE MAINTENANCE AND CONSUMABLE REPLACEMENT
7
Grip the levers at each end of the toner cartridge
with your fingers, then push down firmly to rotate the
levers forward to the (
) position.
8
Pull the toner seal straight up to remove it.
■ Pull the toner seal straight up. Pulling the toner
seal diagonally may tear the seal.
■ If it takes more than five seconds until you
remove the toner seal after inserting the toner
cartridge in the printer, an error message may
appear. In this case, perform step 7 again, or
turn the printer off once and then on again.
9
Replace the top cover.