If the paper has not been raised to the feed position, the CPU turns on the main motor and the paper lift clutch. The paper lift gear turns the sector gear and the bottom plate raises until the top sheet pushes up the paper lift sensor feeler [I]. When the paper lift sensor is de-actuated, the paper lift sensor sends a Low signal to the main board, and then the main motor and the paper lift clutch are turned off. If the tray lift sensor stays HIGH for 7 seconds after the paper lift clutch is turned on, "U5" lights in the operation panel. As paper is fed into the copier, the level of paper stack gets lower. If the level becomes too low, the paper lift sensor is actuated and the CPU energizes the paper lift clutch until the top sheet raises the feeler to de-actuate the paper lift sensor again. This ensures that the paper is always at the correct feed height. 10.3.2 Paper End Detection When the cassette runs out of paper, the paper end feeler [J] drops through a slot in the cassette bottom plate. As it drops, the paper end sensor [K] is actuated by the feeler. The paper end sensor then sends a HIGH signal to the main board. The Add Paper indicator then turns on. The Wait indicator keeps turning on and the machine stops after the copy cycle is finished.
