Automatic document feeder with skew control

Abstract

The disclosed document feeder apparatus includes a document drive that comprises only a single line of feed rollers with a simple skew adjustment system. This drive is shown incorporated in a cassette-loaded automatic document feeder ('ADF') that is attachable to an existing independent engineering document copier in a non-intrusive manner. The cassette can be loaded, either when positioned in the ADF or at a location remote from the ADF, with a stack of large engineering documents of mixed media and varying sizes; and it is even possible for the cassette to carry a document several yards (meters) long. Documents are fed serially from the top of the stack through the ADF's document flow path by the document drive which is centered for alignment along a line positioned parallel to the document flow path. A speed control assembly, all parts of which are located within the ADF itself, adjusts the speed of the document in the ADF feed rollers to match the speed of the independent copier's constant velocity transport. The leading edge of each successive document is sensed and, if not perpendicular to the flow path, is correctly realigned by the skew adjustment system that momentarily reorients one of the ADF's in-line feed rollers to an adjustment position that is slightly out of angular alignment with the feed roller center line.