f927eafa__Printer_Warning_Light_Flashes__Action
[Number of flashes/Cause] Ten flashes: The Front Tray is not set to its correct position./The Front Tray was moved during printing. [Action] 
When printing from the Rear Tray, return the Front Tray to its normal printing position, make sure that paper is loaded in the Rear Tray, then press the RESUME/CANCEL button on the printer to resume printing. Refer to Loading Paper for details about how to return the Front Tray to its normal printing position. If you have moved the Front Tray during printing, return the Front Tray to the correct position, then press the RESUME/CANCEL button on the printer and try printing again. Do not move the Front Tray during printing.
The Meaning of Canon Printer Warning Light Flashes
Action