Canon MF55DD Series Basic Manual page 98

6
While grasping the cartridge with one hand, firmly and slowly pull
the sealing tape tab with the other hand to remove the sealing
tape completely. Throw the tape away.
IMPORTANT
To avoid breaking the tape, do not pull out the tape at an upward or downward angle.
7
Hold the cartridge and position the arrow mark on the cartridge
towards the inside of the machine as shown below.
8
8-16 Replacing the Cartridge
Arrow mark