Recirculating automatic document feeder

Abstract

A document feeder is disclosed wherein a document stack is bent or curved when it rests on a fixed curved stackholding tray. A stack of paper becomes rigid when curved, and therefore, capable of being raised by applying an upward force along the curved edge on each end of the stack provided by a pair of curved lifting blades which move horizontally relative to the ends of the stack to move in and out underneath the edges of the stack, and thereafter move vertically to lift the entire stack out of the path of the returning copy. The document to be copied may be lifted off the top of the document stack either before or after the lifting action of the blades. A vacuum belt type arrangement is provided for moving successive documents from the top of the stack. The document loops through the machine, and returns at a lower level, aligned with an opening beneath the bottom of the stack. A levered plate is provided at the trailing lateral edge of the stack to be sure that the edges of the stack are lifted out of the return paper document path. Moving the belts running beneath the stack carry the returning document into alignment under the stacks; a metal plate running horizontally or laterally along the edge of the stack perpendicular and very close to the belts acts as a stop to stop the returning document in alignment with the document stack being fed. Once the document is returned, the lifting blades move vertically downward, and laterally outward, resting the remainder of the document stack on the returned document and making it a part of the stack.