Brother MFC-9550 Owner's Manual page 181

168
C H A P T E R S E V E N T E E N
4
Wait to unpack the new drum unit until immediately before installing
it. Place the old drum unit into the aluminum bag and discard it
according to local regulations.
New Drum Unit
5
Gently rock the new drum from side to side five or six times.
WARNING
Old Drum Unit