Hybrid sequenced dadf duplexing system

Abstract

Disclosed is a hybrid copying system including a document feeder for a copier with a document bypass loop for copying documents in desired non-linear page sequences for improved copying efficiency, particularly for duplex copying. As shown, documents from a stacked set of document sheets may be fed to the copying station of the copier and then selectively returned directly back to the opposite side of the copying station for copying interleaved between the feeding of other documents fed from the stack, by a document return loop bypass path bypassing the stack and having a path length greater than the dimension of a document sheet. A duplex document which has been copied on one side may be moving in this return loop bypass path while another fed from the stack is being copied, and also be inverted by an integral inverter therein. A post-collation duplex copying system is provided with this document feeder for making duplex copies from duplex document sheets by making two separate buffer sets of plural copies on one side of copy sheets at a time of one side of two different document sheets fed by this document feeder and temporarily retaining and maintain these two separate buffer sets in a duplexing buffer tray in the copier and then copying onto the other sides thereof the other sides of documents fed through the document bypass loop and outputting these completed copies to be sorted by being separately placed in the bins of a multiple bin sorter at the output of the copier, and repeating this until all the documents have been copied. Various examples are disclosed for compatible hybrid simplex and/or duplex and pre or post collation copying, including alternative trayless duplexing and hybrid or non-sequential postcollation sorter operation.