Abstract: An apparatus monitors the motion of sheet, such as in a digital printer. An optical sensor is capable of recording an image in a two-dimensional array of pixels, and has acuity to recognize a terrain of a small area on a sheet that is substantially blank to a human eye. The optical sensor views a portion of a sheet moving in a process direction through a path. A detection system compares at least two recorded terrain images from the sheet, thereby directly measuring velocity and direction of the sheet.

Abstract: A finisher for an image forming apparatus includes a pair of rotatable downstream rollers and a pair of rotatable upstream roller between which a path on which an imaged medium travels. The finisher determines when a trailing edge of the medium is about to leave a nip of the upstream rollers and then stops a leading edge of the medium. By stopping the leading edge of the medium, the medium buckles and the trailing edge registers against the upstream nip line. A finishing device performs a hole punch, staple, or other finishing operation to the medium when the trailing edge registers against the upstream nip line. The finishing operation is performed at a speed equal to or greater than a speed at which the image forming apparatus forms the image on the medium and outputs the medium to the finisher.

Abstract: A semi-active retard feeder employs a hysteresis clutch to provide the resisting torque to a retard roll. A low cost Hall Effect sensor is added to the clutch assembly to provide a feedback signal during the feeding cycle in order to detect the onset of degraded feeding performance. This signal can be used to instruct a user to order and replace the retard roll.

Abstract: An improved method for monitoring stack quality in a finisher of a printer includes examining the net displacement of a compiling tray after each set has been ejected. A deviation from the normal increments of displacement for each set triggers a “tray full” condition which alerts a user to empty the tray.

Abstract: A semi-active retard feeder employs a hysteresis clutch to provide the resisting torque to a retard roll. A low cost Hall Effect sensor is added to the clutch assembly to provide a feedback signal during the feeding cycle in order to detect the onset of degraded feeding performance. This signal can be used to instruct a user to order and replace the retard roll.

Abstract: An improved sloped stack detection system for a multi-function finisher includes a reflective sensor which suspends the conveying of stapled sets to an output tray when staple build-up in small stapled sets causes the stacked output to become sloped.

Abstract: A finisher for an image forming apparatus includes a pair of rotatable downstream rollers and a pair of rotable upstream roller between which a path on which an imaged medium travels. The finisher determines when a trailing edge of the medium is about to leave a nip of the upstream rollers and then stops a leading edge of the medium. By stopping the leading edge of the medium, the medium buckles and the trailing edge registers against the upstream nip line. A finishing device performs a hole punch, staple, or other finishing operation to the medium when the trailing edge registers against the upstream nip line.

Abstract: An improved method for monitoring stack quality in a finisher of a printer includes examining the net displacement of a compiling tray after each set has been ejected. A deviation from the normal increments of displacement for each set triggers a “tray full” condition which alerts a user to empty the tray.

Abstract: An improved sloped stack detection system for a multi-function finisher includes a reflective sensor which suspends the conveying of stapled sets to an output tray when staple build-up in small stapled sets causes the stacked output to become sloped.

Abstract: A system of deskewing sheets moving in a process direction in a sheet path, such for a printer, by variably differentially driving the sheet in transversely spaced apart sheet driving nips formed by sheet driving rollers and mating idler rollers in response to sheet skew sensing. A variable differential nip force is applied via the respective idlers sufficient to provide a differential sheet driving velocity of a sheet in the respective sheet driving nips. The idler rollers may be mounted on a common shaft which is pivoted by a pivoting system to provide sufficiently different nip forces on the two driving rollers for a sufficient time to deskew the sheet. The sheet driving rollers may be commonly driven on a single fixed shaft by a single drive system.

Abstract: Sheet registration with improved sheet deskewing of print media sheets may be provided with an intermediately transversely pivotal baffle member overlying and engaging at least part of a buckled sheet being edge registered so that the effective buckle chamber size and sheet path length on one side of the sheet is automatically different from the other side of the sheet with said pivoting of said pivotal baffle member, to assist in the deskewing of the sheet as it is being partially buckled by the sheet registration system. The direction and amount of baffle pivoting may be self-pivoted by the extent of transverse buckle difference, or positively driven in response to a detected sheet skew.

Abstract: An apparatus monitors the motion of sheet, such as in a digital printer. An optical sensor is capable of recording an image in a two-dimensional array of pixels, and has acuity to recognize a terrain of a small area on a sheet that is substantially blank to a human eye. The optical sensor views a portion of a sheet moving in a process direction through a path. A detection system compares at least two recorded terrain images from the sheet, thereby directly measuring velocity and direction of the sheet.

Abstract: Sheet registration with improved sheet deskewing of print media sheets may be provided with an intermediately transversely pivotal baffle member overlying and engaging at least part of a buckled sheet being edge registered so that the effective buckle chamber size and sheet path length on one side of the sheet is automatically different from the other side of the sheet with said pivoting of said pivotal baffle member, to assist in the deskewing of the sheet as it is being partially buckled by the sheet registration system. The direction and amount of baffle pivoting may be self-pivoted by the extent of transverse buckle difference, or positively driven in response to a detected sheet skew.