Canon MG3500 Series Online Manual page 73

Note
Do not overload envelopes by stacking until the top of the stack touches the
paper guides.
(5) Open the output tray extension.
3. Open the paper output tray.
(1) Open the paper output tray gently, and extend the paper output support.
Important
Be sure to open the paper output tray when printing. If not open, the machine
cannot start printing.
73