Duplex system and method for pre-collation copiers

Abstract

A method and apparatus for providing duplex copies in pre-collated output copy sets from a set of documents recirculated in order by first copying only the even-ordered documents in the set once onto the first sides of substrates and transporting those copies to a buffer; then making individual copies in order of all the documents by alternately copying odd order documents on the reverse side of copies fed from the buffer while alternately copying even ordered documents onto copy substrates fed from a different copy substrate source, and transporting the copies made from the buffer to an output tray to create pre-collated sets while simultaneously transporting the copies from the other copy substrate source to the buffer to replace the copies fed therefrom; repeatedly individually copying all of the documents in the set in the latter manner by a number of document recirculations equal to one less than the total number of copy sets desired, and then, for a last copy set, making copies of only the odd ordered documents onto the reverse side of copies fed only from the buffer.