Here are the steps
1. Turn off the printer
2. Hold down the Resume button and press the Power button.
3. Keep holding down the Power button and let the Resume button go.
4. Press the Resume button 2 times then let BOTH buttons go.
5. Green lights will flash and then stop blinking.
6. When green lights are solid, press the Resume button 4 times.
7. Press the Power button and the printer should turn off, if not,
press the Power button once more.
8. Your printer should respond as normal
You can also visit "how to reset Canon printer to factory settings" to read the full blog.