Abstract: A method of duplex printing on a cut sheet printer having a sheet supply system for feeding sheets to a print station in a first orientation for printing a first image on the first side of the sheet and then in a second orientation for printing a second image on a second side of the sheet includes, for each sheet: (a) estimating a likelihood P1 that, in a print process for printing the first image, the sheet will become damaged to such an extent that the damage will compromise a later print process for printing the second image; (b) comparing the likelihood P1 to a threshold T; and (c) if the likelihood P1 exceeds the threshold T, reversing the print order so that the second image is printed before the first image. The method ensures that the riskier image is printed on the duplex pass. The chances of the sheet with the simplex image then successfully passing through the duplex pass are then increased.

Abstract: A method of duplex printing on a cut sheet printer having a sheet supply system for feeding sheets to a print station in a first orientation for printing a first image on the first side of the sheet and then in a second orientation for printing a second image on a second side of the sheet includes, for each sheet: (a) estimating a likelihood P1 that, in a print process for printing the first image, the sheet will become damaged to such an extent that the damage will compromise a later print process for printing the second image; (b) comparing the likelihood P1 to a threshold T; and (c) if the likelihood P1 exceeds the threshold T, reversing the print order so that the second image is printed before the first image. The method ensures that the riskier image is printed on the duplex pass. The chances of the sheet with the simplex image then successfully passing through the duplex pass are then increased.

Abstract: The present invention provides a printing system with an apparatus for defect detection comprising a sensing unit for sensing a surface geometry or topology of a sheet and for generating data representative of that surface geometry or topology, a processor device for processing the data to detect and classify deformations, and a controller for controlling further progress of the sheet along the transport path of the printing system in dependence upon the deformations detected and classified by the processor device. Furthermore, the invention provides a corresponding method of detecting defects in a printing system.

Abstract: A printing system comprising an apparatus for defect detection in a printing system. The printing system comprises, an image forming device, a sensing unit for sensing a surface geometry of a sheet to be printed and for generating data representative of that surface geometry, a processor device for processing the data; and a controller for controlling further progress of the sheet along a transport path of the printing system in dependence upon the deformations in the surface geometry of the sheet detected and classified by the processor device. The operating conditions the sheet is exposed to at the sensing unit are similar to the operating conditions the sheet is exposed at the image forming.

Abstract: The present invention provides a conveyor mechanism for conveying sheets. The conveyor mechanism comprises a movable conveyor body, a drive mechanism, and an adjustment system configured to detect and correct skewing of the conveyor body, comprising one or more markers provided on or in the conveyor body, a sensor arrangement for detecting each marker at two or more discrete positions, and a processor to determine the skewing of the conveyor body. The conveyor body and the drive mechanism of the conveyor mechanism are mounted on a movable conveyor frame, and the adjustment system includes a frame shifting device comprising one or one or more actuator for shifting or moving the conveyor frame relative to a fixed framework. The invention also provides a related method of correcting skewing in a conveyor mechanism for conveying sheets along a transport path.

Abstract: The present invention provides a printing system with an apparatus for defect detection comprising a sensing unit for sensing a surface geometry or topology of a sheet and for generating data representative of that surface geometry or topology, a processor device for processing the data to detect and classify deformations, and a controller for controlling further progress of the sheet along the transport path of the printing system in dependence upon the deformations detected and classified by the processor device. Furthermore, the invention provides a corresponding method of detecting defects in a printing system.

Abstract: A printing system comprising an apparatus for defect detection in a printing system. The printing system comprises, an image forming device, a sensing unit for sensing a surface geometry of a sheet to be printed and for generating data representative of that surface geometry, a processor device for processing the data; and a controller for controlling further progress of the sheet along a transport path of the printing system in dependence upon the deformations in the surface geometry of the sheet detected and classified by the processor device. The operating conditions the sheet is exposed to at the sensing unit are similar to the operating conditions the sheet is exposed at the image forming.

Abstract: The present invention provides an apparatus (20) for defect detection in a printing system (1). The apparatus (20) comprises: a sensing unit (21) having at least one first sensor device (22) for sensing a surface geometry or topology of a sheet (S) to be printed as the sheet (S) travels on a transport path (P) of the printing system (1) and for generating data (I) representative of that surface geometry or topology; and a processor device (25) for processing the data (I) from the first sensor device (22) to detect and classify deformations (D) in the surface geometry or topology of the sheet (S) based on at least one predetermined criterion, wherein the at least one predetermined criterion is adjustable or variable to suit operating conditions in the printing system (1). Further, the invention provides a corresponding method of detecting defects in a printing system (1).

Abstract: A sheet transport assembly is provided for transporting a sheet along a process unit configured for applying a process to the sheet. The sheet transport assembly comprises a conveying unit comprising a transport belt, which transport belt comprises air permeable openings, the sheet being placed with a contact side on a support surface of the transport belt; a separating unit for separating the sheet from the transport belt, the separating unit comprising a blowing unit connected to an air supply source and arranged adjacent the transport belt to direct a detach air flow through said air permeable openings of the transport belt in a detach area to lift the sheet from the transport belt; and a control unit configured for controlling the units of the sheet transport assembly. The separating unit further comprises a sheet attraction unit arranged for attracting the sheet to the support surface of the transport belt in two attraction areas.

Abstract: The present invention provides a calibration system, comprising a movable conveyor body configured to hold a plurality of sheets, and a drive mechanism which supports and/or drives the movement of the conveyor body to convey the sheets along a transport path. The calibration system is adapted or configured to detect a position and/or a speed of the conveyor body as it conveys the sheets, the calibration system comprising one or more markers which are provided on or in the conveyor body and a sensor arrangement for detecting each marker at two or more discrete positions spaced apart from one another. The markers are distributed along and fixed with respect to the conveyor body, wherein each marker is uniquely identifiable or distinguishable by the sensor arrangement. The present invention also provides an associated method of calibrating a sheet conveyor mechanism.

Abstract: The present invention provides a conveyor mechanism for conveying sheets. The conveyor mechanism comprises a movable conveyor body, a drive mechanism, and an adjustment system configured to detect and correct skewing of the conveyor body, comprising one or more markers provided on or in the conveyor body, a sensor arrangement for detecting each marker at two or more discrete positions, and a processor to determine the skewing of the conveyor body. The conveyor body and the drive mechanism of the conveyor mechanism are mounted on a movable conveyor frame, and the adjustment system includes a frame shifting device comprising one or one or more actuator for shifting or moving the conveyor frame relative to a fixed framework. The invention also provides a related method of correcting skewing in a conveyor mechanism for conveying sheets along a transport path.

Abstract: The present invention provides an apparatus (20) for defect detection in a printing system (1). The apparatus (20) comprises: a sensing unit (21) having at least one first sensor device (22) for sensing a surface geometry or topology of a sheet (S) to be printed as the sheet (S) travels on a transport path (P) of the printing system (1) and for generating data (I) representative of that surface geometry or topology; and a processor device (25) for processing the data (I) from the first sensor device (22) to detect and classify deformations (D) in the surface geometry or topology of the sheet (S) based on at least one predetermined criterion, wherein the at least one predetermined criterion is adjustable or variable to suit operating conditions in the printing system (1). Further, the invention provides a corresponding method of detecting defects in a printing system (1).

Abstract: A sheet conveying device includes a belt arranged to carry sheets from an upstream end to a downstream end of a transport path, the belt having an array of perforations; and an array of suction nozzles arranged below the belt for sucking-in ambient air through the perforations of the belt. At least one blow nozzle is arranged at the downstream end of the transport path for blowing out a gas through the perforations of the belt. The downstream end of the transport path is defined by a deflection roller. A plurality of blow nozzles are formed by circumferential grooves in the peripheral surface of the deflection roller.

Abstract: A reproduction apparatus includes a print unit with print elements for ejecting an amount of ink on a plurality of sheets, of which each size in the direction perpendicular to the transport direction of the sheets under the print unit is smaller than the size of the print unit in the same direction, and a displacing mechanism for displacing the sheets in the same direction. The displacement of the displacing mechanism is so extreme that an alignment of a sheet is variable from an alignment of one side of the sheet with one end of the print unit to an alignment of the other side of the sheet with the other end of the print unit. Also a method for application by such a reproduction apparatus is disclosed.

Abstract: A method of adjusting a lateral position of an endless belt that is passed around at least two rollers, comprising the steps of: controlling a tilt position of a first roller of the at least two rollers; and adjusting a lateral position of the first roller, wherein the lateral position of the first roller is adjusted in combination with controlling the tilt position of the first roller.

Abstract: A printing system includes a marking engine for applying a marking substance onto a sheet and a sheet conveying device. The sheet conveying device includes a belt arranged to carry sheets from an upstream end to a downstream end of a transport path, the belt having an array of perforations; an array of suction nozzles arranged below the belt for sucking-in ambient air through the perforations of the belt; and at least one blow nozzle arranged at the downstream end of the transport path for blowing out a gas through the perforations of the belt. The conveying device further includes an array of anti-friction blow nozzles interleaved with the array of suction nozzles and connected to a blower for blowing-out a gas towards the bottom surface of the belt during the traverse of the sheet along the marking engine.

Abstract: A reproduction apparatus includes a print unit with print elements for ejecting an amount of ink on a plurality of sheets, of which each size in the direction perpendicular to the transport direction of the sheets under the print unit is smaller than the size of the print unit in the same direction, and a displacing mechanism for displacing the sheets in the same direction. The displacement of the displacing mechanism is so extreme that an alignment of a sheet is variable from an alignment of one side of the sheet with one end of the print unit to an alignment of the other side of the sheet with the other end of the print unit. Also a method for application by such a reproduction apparatus is disclosed.

Abstract: A roller for a printer includes an outer tube and at least one inner tube. The inner tube is position within the outer tube. The outer tube extends in an axial direction from a first to a second end and the inner tube extends substantially parallel to the outer tube, defining an inter tubular space between the outer and the inner tube and an intra tubular space within the inner tube. The roller also includes a blocking element dividing the inter tubular space and the intra tubular space into a first part extending substantially from the first end to the blocking element and a second part extending substantially from the blocking element to the second end. A first and a second duct connects the first and second part of the inter tubular space with the second and first part, respectively, of the intra tubular space via the blocking element.

Abstract: A transporting device and method for depositing sheet material on a tray, the transporting device including at least two rollers which can be displaced with respect to each other, with a belt extending between the rollers above the tray, the belt being connected at its ends to the two rollers, whereby the belt can be rolled up onto and unrolled from at least one of said rollers.

Abstract: A roller for a printer includes an outer tube and at least one inner tube. The inner tube is position within the outer tube. The outer tube extends in an axial direction from a first to a second end and the inner tube extends substantially parallel to the outer tube, defining an inter tubular space between the outer and the inner tube and an intra tubular space within the inner tube. The roller also includes a blocking element dividing the inter tubular space and the intra tubular space into a first part extending substantially from the first end to the blocking element and a second part extending substantially from the blocking element to the second end. A first and a second duct connects the first and second part of the inter tubular space with the second and first part, respectively, of the intra tubular space via the blocking element.