Canon LBP7210Cdn Manual page 254

Loading Envelopes in the Multi-purpose Tray
The following envelopes can be loaded in the multi-purpose tray.
Envelope Monarch (98.4 mm x 190.5 mm)
Envelope No.10 (COM10) (104.7 mm x 241.3 mm)
Envelope DL (110.0 mm x 220.0 mm)
Envelope C5 (162.0 mm x 229.0 mm)
Envelope B5 (176.0 mm x 250.0 mm)
IMPORTANT
Loading orientation of envelopes
Load envelopes in the correct orientation as follows.
( : Feeding direction)
Detailed information about usable paper
"Usable Paper and Unusable Paper"
Handling the multi-purpose tray
"Paper Source"
Open the multi-purpose tray.
Holding the opening at the center of the printer, open the multi-purpose tray.