Load Envelopes You can print on plain paper envelopes in 4 1/8 × 9 1/2 inch (#10) (105 × 241 mm) size. 1. Open the paper support and pull up the extensions. 2. Open the output tray, pull out the extensions, and flip up the stopper. 3. Flip the feeder guard up, out of the way, then squeeze the edge guide and slide it left. 4. 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. 5. Slide the edge guide to the edge of the envelopes, but not too tightly. See also: Load Paper for Photos Load Paper for Documents