Brother HL-L8350CDWT - Manual (Page 161)

Routine Maintenance
154
5
Cleaning the corona wires
5
If you have print quality problems, clean the corona wires as follows:
a Make sure that the machine is turned on.
b Press the front cover release button and pull open the front cover.
c
Hold the blue handle of the drum unit. Pull the drum unit out until it stops.