At first power off your printer.
Hold down STOP/RESET button then Press and Hold down Power button
Keep Power button down and Release STOP/RESET button.
Push STOP/RESET button twice.
Release the power button.
Wait 20-30 seconds - Display usually shows "canon Idle".
Push STOP/RESET button four times.
Push Power button twice.
Power off.
your printer have been reset now.