Oce-Technologies B.v.

Daisuke Kawaguchi

Catharinus Van Acquoij

Ernest J J Clevers

Peter George La Vos

Roy H R Jacobs

Johannes H A Dinnissen

Albert M Van Beek

Jeroen P J Huijbers

Johannes P J C Rooijakkers

Hendricus F M Jeurissen

Cornelius M F Janssen

Petrus L J Oteman

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.

Printing system and method for defect detection in a printing system

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.

A method for transferring a sheet in a sheet transport assembly from a supplying conveyor to a receiving conveyor. The method includes arranging a contact side of a sheet in contact with a transport belt of the supplying conveyor, advancing the sheet on the transport belt in a transport direction along a process unit, which applies a process to a process side of the sheet opposite to the contact side, and to a transfer area where the sheet is transferred to a receiving conveyor. To correct for curl deformation of the sheet, air flow is directed onto the process side of sheet, which urges the sheet towards a supporting element. The air flow is controlled in response to a curl deformation behavior of the sheet.

Method for transferring a sheet between two conveyors

A method is provided for determining a sheet height of a sheet conveyed by a sheet transportation unit. An optical sensor is used for sensing the surface geometry of the sheet, resulting in a two-dimensional height image of the sheet. The height image has pixels that have a value representing a local height of the sheet. The method comprises the steps of: a) selecting from the height image pixels that have a deviating value; b) substituting the deviating value of a selected pixel by a realistic value that is derived from not selected pixels; and c) determining a sheet height by finding a maximum value from the values of the not selected pixels and the substituted values. Furthermore, a print system is provided that comprises a control unit that is configured to apply the invented method.

Method for determining a sheet height

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 includes: a conveying unit including a transport belt and a deflection element. The transport belt is configured for advancing the sheet in a transport direction along the process unit to the deflection element, the sheet being placed with a contact side on the belt and a process side towards the process unit. The deflection element is arranged in contact with the transport belt to deflect the transport belt downstream in the transport direction relative to the process unit. The sheet transport assembly further includes a separating unit for separating the sheet from the transport belt. The separating unit is connected to an air supply source. The separating unit includes a restrain blowing device arranged for directing a restrain air flow onto the process side of the sheet in a restrain area for urging the sheet towards the transport belt proximate to the deflection element. The separating unit further includes a lifting blowing device arranged for directing a lifting air flow onto the contact side of the sheet in a lifting area for lifting the sheet from the transport belt. The lifting area is arranged extending only over a middle portion of a width of the sheet, the width being a dimension of the sheet in a lateral direction perpendicular to the transport direction.

Sheet transport assembly

The present invention provides a method of optimizing the operating conditions for printing sheets, comprising the following steps: introducing a sheet into the printing system; treating the sheet by exposing the sheet to a physical operating condition of the printing system at a predetermined level; sensing a surface geometry of the exposed sheet to generate data representing a height map of the surface of the at least one exposed sheet for that predetermined level of that operating condition; and comparing the data to one another and/or a reference value to determine the suitable level of the least one physical operating condition. The invention further provides an apparatus optimizing the operating conditions for printing sheets.

Apparatus and method for determining suitable printing conditions for printing sheets in a printing system

The present invention provides an apparatus () for defect detection in a printing system (). The apparatus () comprises: a sensing unit () having at least one first sensor device () 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 () and for generating data (I) representative of that surface geometry or topology; and a processor device () for processing the data (I) from the first sensor device () 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 (). Further, the invention provides a corresponding method of detecting defects in a printing system ().

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Venlo, Netherlands

Daisuke Kawaguchi