Recirculating documents duplex copier

Claim 2

In a document handling apparatus for plurally recirculating a set of simplex original document sheets to a copier to be copied onto both sides of copy sheets to form pre-collated duplex copy sets, the improvement comprising: means for circulating the documents in reverse (descending) serial page order beginning with the last sheet in the document set and ending with the first sheet in the document set, odd/even determining means for automatically determining whether there are an odd or an even number of original documents in said document set before they are copied, and copying control means, controlled by said odd/even determining means, to inhibit copying of the last, or next to last, and alternate subsequent documents on the first copying circulation of said document set in response to a determination by said odd/even determining means whether there are an odd or even number of original documents in said set, to provide properly collated output duplex copy sets without variable output inversion.

Claim 3

The document handling apparatus of claim 1, wherein in response to the determination by said odd/even determining means that there is an odd number of original document sheets, said copying control means causes the single copying of only the next-to-last and subsequent alternate document sheets on the first copying circulation of said document set, and causes the single copying of only the last and alternate subsequent document sheets on the last copying circulation of said document set, and causes the copying of all said document sheets on all copying circulations of said document set between said first and last circulations thereof.

Claim 4

The document handling apparatus of claim 1, wherein said set of original document sheets is a collated face-up stack of 1 to N page order simplex documents which are individually circulated from the bottom of said stack to the platen of said copier and back to the top of said stack in N to 1 order, with N being the page number of the bottom page of said document stack; and wherein said odd/even determining means determines whether N is an odd or even page number, and wherein if N is determined to be an odd number, the document sheets are copied in the first copying circulation as controlled by said copying control means in the copying order sequence N minus 1, N minus 3, N minus 5, etc., up to the total number of document sheets in said document set, and in at least the second copying circulation all the document pages are copied and the Nth document page is first copied on only one side of a copy sheet as a simplex copy, and in the last copying circulation the document sheets are copied in the copying sequence N, N minus 2, N minus 4, etc., and wherein if N is determined to be an even number, the documents are copied in the first copying circulation in the order N, N minus 2, N minus 4, etc., and copied on the last copying circulation in the order N minus 1, N minus 3, N minus 5, etc.

Claim 5

The document handling apparatus of claims 1, 2 or 3, wherein said copying control means includes duplex buffer means for temporarily storing the copy sheets made of the alternately copied document sheets in said first copying circulation of said document set and for re-presenting all of said temporarily stored copy sheets for the copying of images of alternate document sheets on the opposite sides of all of said stored copy sheets during the subsequent circulation of said document set.

Claim 6

The document handling apparatus of claims 1, 2 or 3, wherein when said odd/even determining means determines that there are an odd number of original documents in said document set, the first copy made in at least the second copying circulation is made from the last document page in the document set onto only one side of a blank copy sheet as a simplex copy sheet.

Claim 7

The document handling apparatus of claims 1, 2 or 3, wherein said odd/even determining means comprises means for circulating the document set in a first single non-copying circulation before any of the documents are copied and counting the number of document sheets which are circulated in said first, non-copying circulation.

Claim 8

The document handling apparatus of claims 1, 2 or 3, wherein all of said copies made from said document set have the correct number of copy sheet inversions in their output whether there are an odd or even number of said original documents without an output inverter.

Claim 9

The document handling apparatus of claim 6, wherein if only two document sheets are counted in said document set during said non-copying circulation said copying control means causes said copier to make multiple copies of said two document sheets in the first copying circulation.

Claim 10

The document handling apparatus of claim 1, wherein in response to the determination by said odd/even determining means that there is an odd number of original document sheets, said copying control means causes the single copying of only the next-to-last and subsequent alternate document sheets on the first copying circulation of said document set, and causes the single copying of only the last and alternate subsequent document sheets on the last copying circulation of said document set, and causes the copying of all said document sheets on all copying circulations of said document set between said first and last circulations thereof, wherein said set of original document sheets is a collated face-up stack of 1 to N page order simplex documents which are individually circulated from the bottom of said stack to the platen of said copier and back to the top of said stack in N to 1 order, with N being the page number of the bottom page of said document stack; wherein said odd/even determining means determines whether N is an odd or even page number, and wherein if N is determined to be an odd number, the document sheets are copied in the first copying circulation as controlled by said copying control means in the copying order sequence N minus 1, N minus 3, N minus 5, etc., up to the total number of document sheets in said document set, and in at least the second copying circulation all the document pages are copied and the Nth document page is first copied on only one side of a copy sheet as a simplex copy, and in the last copying circulation the document sheets are copied in the copying sequence N, N minus 2, N minus 4, etc., wherein if N is determined to be an even number, the documents are copied in the first copying circulation in the order N, N minus 2, N minus 4, etc., and copied on the last copying circulation in the order N minus 1, N minus 3, N minus 5, etc., wherein said copying control means includes duplex buffer means for temporarily storing the copy sheets made of the alternately copied document sheets in said first copying circulation of said document set and for re-presenting all of said temporarily stored copy sheets for the copying of images of alternate document sheets on the opposite sides of all of said stored copy sheet during the subsequent circulation of said document set, and when said odd/even determining means determines that there are an odd number of original documents in said document set, the first copy made in at least the second copying circulation is made from the last document page in the document set onto only one side of a blank copy sheet as a simplex copy sheet, and wherein said odd/even determining means comprises means for circulating the document set in a first single non-copying circulation before any of the documents are copied and counting the number of document sheets which are circulated in said first, non-copying circulation, wherein all of said copies made from said document set have the correct number of copy sheet inversions in their output whether there are an odd or even number of said original documents without an output inverter.

Claim 13

The method of claim 10, wherein regardless of whether there are an odd or even number of original documents, the odd document pages are copied onto the front sides of the copy sheets so that pre-printed or pre-punched copy sheets may be consistently loaded into the copier in either case.

Claim 14

In the method of recirculatively copying a set of original documents in a copier onto both sides of copy sheets to form pre-collated duplex copy sets, including circulating the document set in reverse (descending) (N to 1) serial page order beginning with the last sheet (N) in the document set and ending with the first sheet (1) in the document set, the improvement comprising the steps of: automatically determining whether there are an odd or an even number of simplex original documents in said document set by counting the simplex documents as they are so circulated before they are copied, in the first copying circulation of the document set, copying in said N to 1 order only the last (Nth) and subsequent alternate simplex documents or alternatively only copying the next-to-last (N minus 1) and subsequent alternate simplex documents automatically in response to said determining of whether there are an odd or even number of simplex documents in said set, and in all intermediate copying circulations of the document set, copying all of said simplex documents in said N to 1 order, and in the last copying circulation of the document set, copying the alternate simplex documents not copied on said first copying circulation, to provide a properly collated output of duplex copy sets having consistent copy sheet output inversion.

Claim 15

In the method of recirculatively copying a set of original documents in a copier onto both sides of copy sheets to form pre-collated duplex copy sets, including circulating the document set in reverse (descending) (N to 1) serial page order beginning with the last sheet (N) in the document set and ending with the first sheet (1) in the document set, the improvement comprising the steps of: automatically determining whether there are an odd or an even number of simplex original documents in said document set by counting the simplex documents as they are so circulated before they are copied, in the first copying circulation of the document set, copying in said N to 1 order only the last (Nth) and subsequent alternate simplex documents or alternatively only copying the next-to-last (N minus 1) and subsequent alternate simplex documents automatically in response to said determining of whether there are an odd or even number of simplex documents in said set, and in all intermediate copying circulations of the document set, copying all of said simplex documents in said N to 1 order, and in the last copying circulation of the document set, copying the alternate simplex documents not copied on said first copying circulation, to provide a properly collated output of duplex copy sets having consistent copy sheet output inversion.