Patent ID: 8246041

Claim:
A system for monitoring media stack height in an image forming machine, comprising: a pick mechanism having a pick arm and at least one sheet feeding pick roller, said pick arm rotatably mounted at one end for undergoing pivotal movement about an axis so that the angular position of said pick arm can change relative to said axis, said pick roller mounted to an opposite end of said pick arm, contacting a top of a media stack and driven to feed sheets one at a time from the top of the media stack which changes the height of the media stack such that the angular position of said pick arm relative to the media stack changes as the height of the media stack changes; a media stack height sensing mechanism operatively coupled to said pick mechanism arm to sense angular displacement of said pick arm as the height of the media stack changes to provide an output indicating the quantity of sheets remaining in the media stack, said pick mechanism thereby performing dual functions of feeding sheets from the media stack thereby decreasing the media stack height and of enabling the sensing of the remaining media stack height for providing of an indication of the quantity of sheets remaining in the media stack; and a controller coupled to said media height sensing mechanism that estimates a quantity of sheets remaining in the media stack based on the angular displacement of said pick arm sensed and provides an output indicating the quantity of sheets remaining.