Canon Color Bubble Jet BJC-2000 Series User Manual page 72

Lower the
lock lever.
C
Do not manually move the mechanism that houses the
BJ cartridge. Attempting to move the BJ cartridge holder will
damage the printer.
Set the paper
thickness lever.
Chapter 4
Press the blue lock lever down completely;
do not use excessive force.
The BJ cartridge is now positioned and locked.
If you plan to load envelopes, fabric sheets, or thick paper,
set the lever to the right.
For all other print media, set the lever to the left.
Maintaining the Printer 4-13