Apparatus for detecting number of remaining sheets

摘要

An improved paper feeding device, for example, for a copying machine is provided and is capable of warning a user of the status of available copy paper sheets. A movable support tray can be monitored to provide a measurement of the total initial height of the paper stack and subsequent movements of this paper stack to introduce individual copy paper sheets into a paper transport system can be correlated with the actual number of sheets that are transported. From these monitored values, it is possible to calculate the number of sheets remaining on the stack and to provide an audible, vocal or visual display of the actual number or relative condition to warn a user.