Brother HL-7050N - Manual (Page 158)

ROUTINE MAINTENANCE 5 - 9
HL7050_US_UG_FM5.5
4 Unpack the new drum unit.
Figure 5-14
5 Put the toner cartridge in the new drum unit. If you put the
cartridge in properly, the blue lock lever is lifted automatically.
Figure 5-15
■ Wait to unpack a drum unit until immediately before you
put it in the printer. Exposure to direct sunlight or room
light may damage the drum unit.
■ Do not touch the shaded parts shown in Figure 5-14.
■ Make sure you install the toner cartridge properly, or it may
separate from the drum when you pick up the drum unit.