Hello, my canon ip 1700 printer keeps telling to refill the paper , and there's alot of paper in it already? i know it might be dust on the optical sensor that reads the amount of paper put on to it , but i don't know how to take it out and clean it or where it is located?
I don't think there is an "Optical Sensor " there, more like a mechanical arm that is pushed back once the paper is loaded in the tray.
What you need is a can of compressed air and after removing the cartridge, very carefully clean by blowing into the end of the tray where you load the paper.
Check if the small mechanical arm is not broken or bent or then pushed upwards towards the top of the tray or towards the back of the tray.