Copier keeps telling us there is paper jam, we have looked where screen shows jam and find nothing. We have taken out the paper tray, still don't find even a tiny scrap of paper anywhere.

There are several possibilities. After you inspect for the Jam and close the drawer, does the copier come to ready? Have you checked the behind the doors on the right side. If the copier comes to ready and you press the start button does the copier jam right away. If so check the dial on the paper drawer and be sure its set to the right size paper. If its not the copier will jam, right away. It is important with a Canon to check all areas and open both the paper drawer and the right side doors when checking for jam, if the right sequence is not followed in checking for jams the jam may not clear. If still Jammed you might take some canned air open the right side door and blow out the paper feed area, a sensor may be blocked or dusty. If all else fails turn the machine off and un-plug it from the wall, let it set a few minutes and plug it in and try it again.