Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
A recirculating automatic document feeder (RADF) having an antireflective, interrupt optical sensor to detect the returning of a sheet to the document stack, after copying. In Fig. 1, RADF 10 is shown associated with copier platen 11. This RADF is a top-feed/bottom-restack device. A housing 12 is movable, as indicated by arrow 13, in order to place a stack-pick-up mechanism 14 at the proper location relative the left-hand edge of stack 15. This range of movement is about one-half inch. Stack 15 is also supported somewhat elevated by operation of air-table 40. The optical sensor of Fig. 2 is in the bottom of housing 12, and is movable therewith. This optical sensor comprises a light-emitting diode (LED) 20 and a light-receiving photocell 21. LED 20 directs light vertically downward.