Abstract: A sheet inverter includes a sheet path, such as a curved sheet path. A sheet driver is positioned to receive a sheet along the sheet path. The sheet driver is adapted to draw in the sheet and reverse a direction of the sheet. An exit path is positioned to receive the sheet from the sheet driver. An inverter path is also positioned to receive the sheet from the sheet driver. The curve of the sheet path biases the sheet's trailing edge into the exit path and the inverter path, and the sheet is directed to the exit path or the inverter path depending only upon how far the sheet is drawn into the sheet driver.

Abstract: A substrate inverter, comprising: an inversion channel having an input path having an input nip and output path having an output nip; input drive means for driving a substrate into the inversion channel means in an initial incoming direction so that a leading edge and trailing edge of the substrate pass by the input nip until the trailing edge of substrate reaches a first position in the inversion channel; output drive means for driving the substrate out of the inversion channel in an output direction generally opposite the initial incoming direction; the output drive means includes a nip for engaging the leading edge of the substrate when the substrate is in the first position; a Controller, responsive to the output drive means, for adjusting speed of the output drive means so that substrate is driven a first speed until the trailing edge of substrate reaches a second position in the inversion channel, and second speed when the trailing edge passes the second position or stop.

Abstract: A substrate inverter, comprising: an inversion channel having an input path having an input nip and output path having an output nip; input drive means for driving a substrate into said inversion channel means in an initial incoming direction so that a leading edge and trailing edge of said substrate pass by said input nip until said trailing edge of substrate reaches a first position in said inversion channel; output drive means for driving said substrate out of said inversion channel in an output direction generally opposite said initial incoming direction; said output drive means includes a xnip for engaging said leading edge of said substrate when said substrate is in said first position; a Controller, responsive to said output drive means, for adjusting speed of said output drive means so that substrate is driven a first speed until said trailing edge of substrate reaches a second position in said inversion channel, and second speed when said trailing edge passes said second position.

Abstract: In accordance with one aspect of the invention, there is provided an apparatus for guiding a sheet in a stream of sheet progressing through a paper path of a printing machine. The apparatus includes an input feed mechanism for feeding the sheets in a first direction. The apparatus also includes a guide which is operably associated with the input feed mechanism for guiding the sheets along the first direction. The apparatus further includes a movable gate operably associated with the guide. The gate and the guide define a passageway therebetween for passing sheets therethrough. The passageway has a first width at a first position of the gate selected for passing sheets therethrough having a thickness less than a first thickness. The first width of the passageway is selected for inhibiting sheets therethrough having a thickness greater than the first thickness.

Abstract: In accordance with one aspect of the invention, there is provided an apparatus for guiding a sheet in a stream of sheet progressing through a paper path of a printing machine. The apparatus includes an input feed mechanism for feeding the sheets in a first direction. The apparatus also includes a guide which is operably associated with the input feed mechanism for guiding the sheets along the first direction. The apparatus further includes a movable gate operably associated with the guide. The gate and the guide define a passageway therebetween for passing sheets therethrough. The passageway has a first width at a first position of the gate selected for passing sheets therethrough having a thickness less than a first thickness. The first width of the passageway is selected for inhibiting sheets therethrough having a thickness greater than the first thickness.

Abstract: A pretransfer sheet feeding device for an electrophotographic printing machine that minimizes impact with and delivers a sheet to a photoreceptor at a desired tangential position. The sheet feeding device includes a selectively engageable drive nip and a biased baffle member which forms a buckle chamber. There is further a plurality of rollers located so as to provide substantially frictionless directional guidance to the sheet while also inducing a predetermined bend to the sheet so as to deliver the sheet to the photoreceptor. The pretransfer rollers are also moveable so that the angle of approach of a sheet can be adjusted based on sheet weight or other characteristics. Once the sheet is tacked to the photoreceptor in the transfer zone, the disengageable drive nip is released and the sheet is controlled by the photoreceptor so that speed mismatch is not a problem.

Abstract: A sheet aligning and registration device for a printing machine. In a stalled roll registration device there is provided a drive mechanism preceding the stalled roll and a sensor to determine the size of a buckle formed in a sheet as it is fed into the registration nip formed by the stalled roll pair. When the buckle reaches a predetermined size the sensor generates a signal which causes the drive controller to briefly pulse the registration roll pair. This brief pulse of the registration roll pair captures the sheet in the nip in a deskewed and registered position for subsequent feeding in a timed relationship to a machine subsystem. A baffle located between the drive nip and registration nip directs the sheet buckle formation in a controlled manner so that proper deskewing and registration forces are obtained.

Abstract: A device for inverting a sheet along a path in an electric photographic printing machine. A gateless sheet inverter is provided in which a curved portion of a sheet path branch intersects a second portion of the sheet path to form a curved inverter throat. As the sheet is driven from the curved branch portion of the path into the throat portion the beam strength of the sheet causes the trail edge of the sheet to flip toward a second nip leading to the second sheet path. A pair of reversing rolls captures the lead edge of the sheet to be inverted and then reverses to drive the sheets out of the second nip formed by a tri-roll arrangement. A sheet having a radius of curvature equal to or greater than the radius of curvature of the throat will be guided along the throat baffle and fed through the second nip. To further assist in assuring the trail edge flips to the second sheet path an air knife can be added at the intersection of the path branches to assist in moving the trail edge into the second path branch.

Abstract: A prefuser vacuum transport apparatus that increases the latitude of sheet acquisition includes at least one perforated belt entrained around a vacuum plenum to provide a limited drive force on sheets being driven by the vacuum transport apparatus. The vacuum plenum includes a vacuum port surface having a profile that is contoured to follow the profile of the stiffest sheet to be transported with the maximum specified curl. The belt follows the port surface contour.

Abstract: An apparatus in which a sheet is registered during the movement thereof. The sheet is moved along a path in a forward direction of movement and a lateral force is applied thereto. The lateral force causes the sheet edge to engage a moving registration edge at which time the lateral motion is discontinued and the sheet continues along its path with virtualy no loss of velocity. As a result of the movement of the registration guide the relative velocity between the sheet and the guide is zero thereby substantially eliminating wear to the guide.

Abstract: A non-contact, transmissive energy sensor is utilized for determining the thickness of paper sheets in a feed path. The sensor includes an energy emitting source and an energy detector, the output of the energy detecting source being proportional to the amount of energy received by the energy detector. The signal output level of the detector is utilized in a model to determine the basis weight of paper in the detecting zone of the detector. Heuristic sampling techniques can be utilized to reduce or eliminate the effects of images printed on the paper and flutter of the paper as it moves. An automatic calibration routine utilizing boundary coefficients is used to calibrate the paper basis weight detection system. The paper basis weight determination is utilized to control subsequent operations to which the paper sheet is subjected in order to optimize image quality and sheet handling, and to control finishing operations.

Abstract: A reproduction machine adapted for producing copies of an original on both sides of a copy sheet and forwarding the finished copy to a collator. An inverter-reverser is employed which allows single-sided copy to a waiting station for subsequent processing to allow copying on the reverse side of the sheet to produce duplex copies, and for inverting duplex copies prior to delivery to the collator to provide the required sheet orientation in the collator. A sheet buckle control device cooperates with the inverter-reverser to insure that papers of widely different paper sizes, weights and stiffness will be inverted during the inverting stage of delivery of duplex copies.