METHODS FOR SHEET SCHEDULING IN AN IMAGING SYSTEM HAVING AN ENDLESS DUPLEX PAPER PATH LOOP

Methods for scheduling sheets in an imaging system having an endless duplex paper path loop are disclosed. Preferably, the duplex loop includes a single sheet inverter without a buffer tray so as to eliminate the problems associated therewith. The basic method involves consecutively inserting copy sheets to be imaged into the duplex loop without placing any skipped pitches therebetween regardless of set or job boundaries. Duplex side ones from subsequent sets or jobs are used to fill any gaps which exist in the duplex side one sheet stream of earlier sets or jobs. Additional refinements include using simplex sheets to fill potential skipped pitches in a duplex side one sheet stream by converting simplex sheets located immediately subsequent to the duplex sheets into duplex sheets having a blank back side and scheduling the side one imaging of the now-converted duplex sheets into the potential skipped pitches. Potential skipped pitches can also be filled by shifting an appropriate number of simplex sheets at a simplex-to-duplex transition into any potential skipped pitches in an immediately subsequent duplex side one sheet stream. Further refinements include using duplex or simplex sheets to fill gaps which exist in a duplex side two sheet stream due to skip requests which occurred during the side one scheduling, inserting or imaging.