How to Load Envelopes into a Canon PIXMA PM970 Series Printer

Insure the envelopes are prepared for printing by pressing down on all four corners and along the edges to flatten them down. Flatten the leading edge of any envelope that is curled or puffed up by pressing down on it with a pen until its crease is sharp and defined.
Load up to 10 envelopes into the upper paper tray, print side up and flap side down. Align the envelopes with the bottom of the envelope against the right side of the Paper Support Guide. Pinch the Guide and slide it to the left until it is snug against the envelopes.
Press the 'Paper Feed Switch' located below the 'ON/OFF' switch on the operations panel to select the rear paper feed. The light above the Paper Feed Switch should indicate the Rear Paper Tray has been selected.
Open the print application on your computer. Select the 'Media Type' option. Select 'Envelope,' and under the Page Size option select either 'Comm. Env. #10' or '#10 Envelope.' Under Orientation select 'Landscape' and hit 'Print.'