Load Envelopes You can print on plain paper or air mail envelopes in 4 1/8 × 9 1/2 inch (105 × 241 mm) [#10] size. 1. Open the paper support, then open the output tray and pull out the extension. 2. Flip the clear plastic feeder guard forward, then squeeze the edge guide and slide it left. 3. Load up to 10 envelopes against the right side and beneath the tab. Load them printable side up and flap edge left. Tip:Press each envelope flat before loading it or load one envelope at a time. 4. Slide the edge guide to the edge of the envelopes, but not so tight that the envelope bows. 5. Flip the clear plastic feeder guard back. See also: Load Paper for Photos Load Paper for Documents