Jam detector for intermediate tray of a copying machine

摘要

A jam detector for a copying machine includes an optical system with a light emitting element and a light receiving element placed above an intermediate tray for temporarily supporting copy paper after one of its sides has been processed until it is transported away to be processed for the second time. The optical system passes a light beam along the entire length of the tray in the direction of motion of the paper such that the beam is obstructed whenever a sheet is dropped from above into the tray and the jam is detected if the beam is not obstructed at regular intervals.