Use standard envelopes with diagonal seams and flaps.
To prevent jams in the multi-purpose tray, do not use the following -Envelopes with windows, holes, perforations, cutouts, and double flaps -Envelopes made with special coated paper or deeply embossed paper -Envelopes with peel-off sealing strips -Envelopes with letter enclosed
You may be able to load other size envelopes than those specified. However, Canon cannot guarantee consistent performance on these.
When printing on envelopes, be sure to use face-up delivery.