Canon imageCLASS MF5850dn Basic Operation Manual page 60

③ Hold down the four corners of the
envelopes firmly, so that they and the
sealed or glued portion stay flat.
– Do not print on the back side of the envelopes
(the side with the flap).
– If the envelopes become filled with air, flatten
them by hand before loading them into the
multi-purpose tray.
Load the envelopes, as shown below.
The display for specifying the paper size and
type appears if <MP TRAY STD SET> is set to
<OFF>. For details, see "Setting Paper Size and
Type, " on p. 2-17.
– The multi-purpose tray can hold five envelopes
at a time.
– Envelopes may be creased in the printing
process.
Loading Paper
2-15