Canon BJC-55 - Manual (Page 54)

4.
With the tip of your finger, lift up the green tab on the corner of the
BJ Cartridge then raise the cartridge and green print head unit out of
the cartridge holder. The white and Grey tabs are used for replacing
the ink cartridge.
Always hold a BJ Cartridge by its sides and never touch the wet print
head or metal contacts.
52 Chapter 3 Printing
Hold the green tab
to remove the BJ
Cartridge.
Do not touch here!