Canon BJ-20 User Manual page 54

Turn the printer on, and the printer is ready for auto paper feed printing.
Caution
Before removing the paper from the bin, always close the bin
first.
Loading Envelopes,
Transparencies, or
Thick paper
Check that the ON LINE indicator is off. Turn it off by pressing the ON LINE
1
switch, if necessary.
2
While referring to the paper guide, insert the envelope ensuring it is straight.
The example below show how to load an envelope. Make sure
the paper thickness adjustment dial (page 46) is set toward the
back of the printer.
Turn on the printer if it is not.