Canon MX720 Series Online Manual page 14

• Check 7: If two or more sheets of paper feed from the cassette at once,
clean the inside of the cassette.
For information on cleaning the inside of the cassette, refer to Cleaning the Pad in the Cassette.
• Check 8: Are the transport unit cover and the rear cover attached
properly?
Refer to Rear View for the position of the rear cover.