Align the edges of the envelope on a flat surface.
Loading Envelopes in the Multi-Purpose Tray
Load the envelopes Monarch, COM10, DL, or ISO-C5 in portrait orientation (with the short edge toward the machine),
with the non-glued side (front side) face up. You cannot print on the reverse side of envelopes.
Load the envelopes so that the edge with the flap is toward the left side as shown in the illustration.