How should I load envelopes?

You can print on plain paper envelopes in this size: No. 10 (4.1 × 9.5 inches [105 × 241 mm]).
1. Flip the feeder guard forward.
   
2. Raise the paper support and its extension, pull out the output tray, then raise the paper stopper.
   
3. Slide the edge guide to the left.
   
4. Load up to 10 envelopes against the right side. Load them printable side up and flap edge left.
   
5. Slide the edge guide against the envelopes, but not too tightly.
   
6. Flip the feeder guard back.
Always follow these loading guidelines:
• If you have trouble loading a stack of envelopes, press each envelope flat before loading it or load one envelope at a time.
• Do not load envelopes above the arrow mark inside the edge guide.
• Do not load envelopes that are curled, folded, or too thin, or that have plastic windows.