Konica Minolta PagePro 1380 MF User Manual page 32

Before loading envelopes, press them down to make sure that all
air is removed, and make sure that the folds of the flaps are firmly
pressed; otherwise, the envelopes may become wrinkled or a
media misfeed may occur.
Load envelopes lengthwise with the side to be printed facing up as
shown in the illustration.
4
Squeeze the right media guide
and adjust the media guides so
that both the left and right sides
of the media are secure. Then,
replace the tray cover on the
media tray.
After the envelope is fed into the output tray, immediately open its
flap (before it has cooled). Because the envelopes pass through
heated rollers, the gummed flaps may seal. Using envelopes with
emulsion-based glue avoids this problem.
34 Loading media