Brother HL-5450DNT - Manual (Page 124)

118
Routine Maintenance
5
m
Put the toner cartridge back into the drum unit until you hear it lock into place. If you put the cartridge in
correctly, the green lock lever on the drum unit will lift automatically.
Note
Make sure that you put in the toner cartridge properly or it may separate from the drum unit.
n
Put the drum unit and toner cartridge assembly back into the machine.
o Close the front cover of the machine.
p Turn on the machine.