Methods for sheet scheduling in an imaging system having an endless duplex paper path loop

In a method of scheduling a series of sheets for insertion into, forming of images on, and outputting from an imaging system, said imaging system having an endless duplex paper path loop providing a plural copy sheet capacity duplexing path equal to M pitches for recirculating therein plural copy sheets imaged on one side back to be imaged on their opposite side to make duplex copies, said imaging system including means for forming images on sheets in a portion of said duplex paper path loop, means for inverting copy sheets imaged on one side prior to being recirculated back to be imaged on their opposite side, and control means for controlling the flow of copy sheets through said duplex paper path loop so that sheets to be duplex imaged are inverted and recirculated back to said means for forming images after being imaged on one side while sheets to be simplex imaged are outputted from said duplex paper path loop after being imaged on one side, said method of scheduling including scheduling sheets for simplex imaging by determining a pitch of said duplex paper path loop into which the sheet will be inserted and imaged on one side and scheduling sheets for duplex imaging by determining a pitch of said duplex paper path loop into which the sheet will be inserted and imaged on side one, said same pitch being reserved for said same sheet to receive its side two image upon being recirculated back to said means for forming images, the improvement comprising:

• (a) determining whether a pitch located adjacent an insertion station is reserved for a duplex sheet side two image and scheduling the side two image to be formed on this sheet if so reserved, then repeating step (a);
• otherwise
• (b) determining the number of pitches since the last sheet which was a duplex side one was scheduled;
• and
• (c) scheduling the next available unscheduled sheet for side one imaging at the pitch located adjacent said insertion station and reserving said pitch for said same sheet to receive its side two image if it is a duplex sheet unless the determined number of pitches in step (b) is less than M, said next available unscheduled sheet is simplex, and an immediately previous scheduled pitch was for a side one duplex image, then repeating step (a).

A method of scheduling sheets for printing and outputting collated sets of plural copy sheets from a multiple job set of multiple electronically reorderable page images, wherein said collated outputted copy sheets include at least duplex sheets having one said page image printed on one side of a copy sheet and another page image printed on an opposite side of said copy sheet, and wherein said printer includes an endless duplex paper path loop providing a plural copy sheet capacity duplexing path for recirculating therein plural copy sheets image on one side back to be image on their opposite side to make said duplex copies, said method comprising:

• scheduling a series of sheets for being passed through said duplex loop, said scheduling including:
• determining when each sheet is to be inserted into the duplex loop;
• determining when a side one image for each sheet in the duplex loop is to be printed on each sheet;
• determining when a side two image for each sheet in the duplex loop which has been printed with a side one image is to be printed on an opposite side of each sheet and
• determining when each sheet is to be outputted from said duplex loop;
• inserting each consecutive sheet into the duplex loop at an insertion station according to said scheduling;
• monitoring said inserting, and determining whether and where any scheduled sheet gaps exist between sheets in said duplex loop which have been printed with a side one image;
• and
• modifying said scheduling so that said unexpected gap is filled when said gap is located adjacent said insertion station by inserting and scheduling the next available sheet for side one imaging in said unexpected gap.

In a method of scheduling a series of sheets for insertion into, forming of images on, and outputting from an imaging system, said imaging system having an endless duplex paper path loop providing a plural copy sheet capacity duplexing path equal to M pitches for recirculating therein plural copy sheets imaged on one side back to be imaged on their opposite side to make duplex copies, said imaging system including means for forming images on sheets in a portion of said duplex paper path loop, means for inverting copy sheets imaged on one side prior to being recirculated back to be imaged on their opposite side, and control means for controlling the flow of copy sheets through said duplex paper path loop so that sheets to be duplex imaged are inverted and recirculated back to said means for forming images after being imaged on one side while sheets to be simplex imaged are outputted from said duplex paper path loop after being imaged on one side, said method of scheduling including scheduling sheets for simplex imaging by determining a pitch of said duplex paper path loop into which the sheet will be inserted and imaged on one side and scheduling sheets for duplex imaging by determining a pitch of said duplex paper path loop into which the sheet will be inserted and imaged on side one, said same pitch being reserved for said same sheet to receive its side two image upon being recirculated back to said means for forming images, the improvement comprising:

• (a) determining whether a pitch located adjacent an insertion station is reserved for a duplex sheet side two image and scheduling the side two image to be formed on this sheet if so reserved, then repeating step (a);
• otherwise
• (b) determining whether the next available unscheduled sheet is duplex and scheduling said next available unscheduled sheet for side one imaging at the pitch located adjacent said insertion station and reserving said pitch for said same sheet to receive its side two image if its is a duplex sheet, then repeating step (a);
• otherwise
• scheduling said next available unscheduled sheet for simplex imaging unless said sheet has a final destination the same as an immediately previously scheduled sheet, said immediately previously scheduled sheet is duplex and pitches reserved for receiving duplex side two images exist in said duplex paper path loop, then repeating step (a).

A method of scheduling sheets for printing and outputting collated sets of plural copy sheets from a multiple job set of multiple electronically reordable page images, wherein said collated outputted copy sheets include at least duplex sheets having one said page image printed on one side of a copy sheet and another page image printed on an opposite side of said copy sheet, and wherein said printer includes an endless duplex paper path loop providing a plural copy sheet capacity duplexing path for recirculating therein plural copy sheets imaged on one side back to be imaged on their opposite side to make said duplex copies, said method comprising:

• determining a duplex printing schedule for printing a series of sheets to be passed through said duplex loop and having duplex printing performed thereon, said determining including:
• determining when each sheet is to be inserted into the duplex loop;
• determining when a side one image for each sheet in the duplex loop is to be printed on each sheet;
• determining when a side two image for each sheet in the duplex loop which has been printed with a side one image is to be printed on an opposite side of each sheet;
• and
• determining when each sheet is to be outputted from said duplex loop;
• determining whether any sheet gaps exist in said duplex printing schedule between said side one image printing and said side two image printing;
• and
• modifying said duplex printing schedule if gaps exist therein by inserting any simplex sheets which have been scheduled for printing immediately prior to said duplex printing schedule into said gaps.

In a method of scheduling a series of sheets for insertion into, forming of images on, and outputting from an imaging system, said imaging system having an endless duplex paper path loop providing a plural copy sheet capacity duplexing path equal to M pitches for recirculating therein plural copy sheets imaged on one side back to be imaged on their opposite side to make duplex copies, said imaging system including means for forming images on sheets in a portion of said duplex paper path loop, means for inverting copy sheets imaged on one side prior to being recirculated back to be imaged on their opposite side, and control means for controlling the flow of copy sheets through said duplex paper path loop so that sheets to be duplex imaged are inverted and recirculated back to said means for forming images after being imaged on one side while sheets to be simples imaged are outputted from said duplex paper path loop after being imaged on one side, said method of scheduling including scheduling sheets for simplex imaging by determining a pitch of said duplex paper path loop into which the sheet will be inserted and image on one side and scheduling sheets for duplex imaging by determining a pitch of said duplex paper path loop into which the sheet will be inserted and imaged on side one, said same pitch being reserved for said same sheet to receive its side two image upon being recirculated back to said means for forming images, the improvement comprising:

• (a) determining whether a pitch located adjacent an insertion station is reserved for a duplex sheet side two image and scheduling the side two image to be formed on this sheet if so reserved, then repeating step (a);
• otherwise
• (b) determining whether a simplex-to-duplex side one transition occurs within a group of M sheet which have not yet been scheduled, if said transition does occur, shifting all sheets in a first subgroup of contiguous duplex sheets within said group of M sheets ahead of a first simplex sheets in said group of M sheets, and proceeding to schedule all of the sheets in said Group of M sheets after said shifting, then repeating step (a).

In a method of scheduling a series of sheets for insertion into, forming of images on, and outputting from an imaging system, said imaging system having an endless duplex paper path loop providing a plural copy sheet capacity duplexing path equal to M pitches for recirculating therein plural copy sheets imaged on one side back to be imaged on their opposite side to make duplex copies, said imaging system including means for forming images on sheets in a portion of said duplex paper path loop, means for inverting copy sheets imaged on their opposite side, and control means for controlling the flow of copy sheets through said duplex paper path loop so that sheets to be duplex imaged are inverted and recirculated back to said means for forming images after being imaged on one side while sheets to be simplex imaged are outputted from said duplex paper path loop after being imaged on one side, said method of scheduling including scheduling sheets for simplex imaging by determining a pitch of said duplex paper path loop into which the sheet will be inserted and imaged on one side and scheduling sheets for duplex imaging by determining a pitch of said duplex paper path loop into which the sheet will be inserted and imaged on side one, said same pitch being reserved for said same sheet to receive its side two image upon being recirculated back to said means for forming images, the improvement comprising:

• (a) determining whether a pitch located adjacent an insertion station is reserved for a duplex sheet side two image and scheduling the side two image to be formed on this sheet if so reserved, then repeating step (a);
• otherwise
• (b) determining whether a simplex-to-duplex side one transition occurs within a group of M sheets which have not yet been scheduled, and if said transition does occur, shifting all sheets G, in a first subgroup of contiguous duplex located after said simplex-to-duplex transition ahead of a number M-G of simplex sheets located just prior to said transition if G is less than M, and proceeding to schedule all of the shifted sheets after said shifting, then repeating step (a).