5. The automatic document handling system of claim 3 wherein if said documents are simplex documents and duplex copying thereof is selected said control means automatically causes said first circulation of said document set to be a non copying circulation and then initiates a special initial copying circulation of only the document sheets in only one of said two trays in a second circulation of said document set, and then automatically initiates alternately sequentially feeding from both of said two trays in subsequent circulations of said document set.
3. The automatic document handling system of claim 1 wherein said automatic sheet separation means separates said document sheets in their return from said imaging station to said two document trays.