US 5,467,182 A · Sheet transport for high productivity trayless duplex

Abstract

A duplex path loop having a acceleration nip cooperating with a belt transport and retime nip to allow duplexing of sheets while minimizing skipped pitches on the photoreceptor. As each sheet to be duplex printed is removed from the process path after first side imaging it is accelerated to create a gap between it and subsequent sheets. The sheet is then stalled or slowed in a retime nip, while subsequent sheets to be duplexed are simultaneously driven by the same transport, the first mentioned sheet being reinserted into the process path at the proper time for receiving the second side image before the arrival of the second sheet at the retime nip. Subsequent duplex sheets are handled in the same manner so that duplex copies are interleaved or otherwise reinserted into the process path with first side copies so that skipped pitches on the photoreceptor are minimized.

Claims11

Dependent claims

A sheet feeding apparatus for feeding cut sheets in timed relationship comprising:

a first sheet drive;
a second sheet drive adjacent said first drive so that a sheet is fed from said first drive and then controlled by said second drive;
a timing mechanism adjacent said second drive to sequence the copy sheet into a process path, said second drive positively driving the sheet to said timing mechanism and then slipping relative to the sheet while simultaneously driving a second sheet toward said timing mechanism so that the speed of the first sheet is altered so that it is fed in the proper timed relation into the process path.

An electrophotographic printing machine having a given sheet printing rate in which copy sheets are selectively printed in a duplex mode having printed image data printed on both sides of a sheet having a trayless, high-productivity duplex path for transporting a sheet having an image on one side of the sheet from an output portion of a process path back into the process path to have a second image transferred to the second side thereof, comprising:

a first sheet drive adjacent the output portion of the process path operating at a speed substantially higher than the sheet printing rate;
a second sheet drive adjacent said first drive operating at a speed substantially equal to the sheet printing rate so that a copy sheet is accelerated from the process path into the duplex path and then controlled by said second drive;
a timing mechanism adjacent said second drive to sequence the copy sheet into the process path to the transfer station to complete duplex printing, said second drive positively driving the sheet to the timing mechanism and then slipping relative to the sheet while simultaneously driving a second sheet toward the timing mechanism so that the speed of the first sheet is altered to achieve proper reimage timing and the first sheet is then forwarded into the process path.

Dependencies are inferred from the claim text.

Sheet transport for high productivity trayless duplex

Life of this patent

Sheet transport for high productivity trayless duplex

Life of this patent

Abstract

Claims11