Auto document feeder for use with duplex copying machine

Abstract

The auto document feeder is for use with duplex copying machines, and is capable of inverting duplex sheet originals, having images on both surfaces, automatically and feeding the originals to an exposure station automatically. The feeder comprises trays for stacking a plurality of sheet originals to be copied, sheet feeding devices for feeding the sheet originals individually from the trays to the exposure station, a platen belt mounted on the exposure station and operable to transport a sheet original across the exposure station and to maintain each sheet original in close contact with the exposure station during exposure of the sheet original, from either side of the exposure station, sheet inverting devices for inverting sheet originals received from the exposure station, and a sheet transport device for transporting inverted sheet originals to the exposure station for completing the duplex copy. In one preferred embodiment, two substantially identical sheet original tables are disposed on opposite sides of the exposure station, and each original table has a sheet feeding device, a sheet inverting or reversing device, and the associated elements. In another embodiment, a single sheet original cassette is used as a tray and is combined with a single upright sheet inverting or reversing device, whereby sheet originals are automatically inverted and fed to the exposure station.