Eastman-kodak Company

Nexpress Solutions, Inc.

Ralph Petersen

Patrick Metzler

Ingo Klaus Dreher

Karlheinz Walter Peter

Heiko Hunold

Frank Pierel

Christopher B Liston

Stefan Schrader

Jan Dirk Boness

John R Thompson

Robert Michael Peffer

Donald Calvin Buch

Wolfgang Eberhard Luxem

Matthias Wecker

Soenke Schmidt

Dirk Kahl

Matthias Prinz

Norbert Freyer

G&uuml;nther Voss

Stephan Walter Pareigis

Tim D'Avis

Michael Mordhorst

Nikolai Neefe

Bernhard G Steuernagel

Ralf Jachmann

A method for detecting errors in individual color separation images of a multi-color printing machine, in particular an electrophotographic printing machine, comprising a plurality of printing units, is described. Using this method, first a plurality of first register lines is printed with a first printing unit, and a plurality of second register lines is printed with a second printing unit in such a manner that each of the first register lines, together with one of said second register lines, is positioned inside a respective registration frame. Then the plurality of the first and second register lines in the respective registration frame are detected with a register sensor, and an output signal of the register sensor relating to the respective second register line is compared with an intensity threshold value in order to determine whether the second register lines can be recognized. In an alternative embodiment of the method, a plurality of the first register lines is printed with a first printing unit in such a manner that each of the first register lines is printed within a respective registration frame. Subsequently, the plurality of the first register lines in the respective registration frames is detected with a register sensor, and an output signal of the register sensor relating to the respective first register lines is compared with a pre-specified intensity threshold value in order to determine whether the first register lines are recognizable.

Method for detecting errors in individual color separation images of a multi-color printing machine

Color separations of a printing image are aligned on a printing material perpendicular to the transport direction of the printing material. A front edge and a rear edge of a register mark are detected. Their distances and, at least in some regions, their widths along the traveled distance of the transport belt between the detection of the front edge and of the rear edge of the register mark are determined. Misalignments of the imaging devices used for the color separations are determined and corrected using these distances and widths.

Method for aligning color separations of a printing image on a printing material

The invention relates to a method of ensuring a correct lateral registration setting, in a digital multi-color electrographic sheet-printing machine, which the sheets adhere to a support, preferably a transport belt, are transported past printing units.

Method of ensuring a correct lateral registration setting and printing machine suitable therefor

In a method for automatically identifying a conveyor belt in a printer as being one of a plurality of belt types, the conveyor belt is moved along a circulatory path. A start and an end of a longitudinal marking on the moving conveyor belt are detected. A distance of travel of the moving conveyor belt between the detecting of the start and the end is sensed to provide a sensed marking length. The sensed marking length is allocated to a nearest of a plurality of nominal marking lengths. Each nominal marking length is associated with a respective one of said belt types. The belt type is associated with or defined by a set of one or more printer control parameters.

Method for automatically identifying a type of transparent conveyor belt

Controlling a sensor mechanism for a printing machine, in which the sensor mechanism in a printing machine detects, in an initial operational mode, at least one mark and the detection of the mark initiates a second operational mode in which the optical density and the color of the mark are detected by the sensor mechanism.

Sensor mechanism for a printing machine

The invention relates to a method and apparatus for minimizing the influence of register differences in multicolor printing, in particular in digital printing processes, register values () in the transport direction (), which are different transversely with respect to this direction being set to a value between the extremes ('). The invention is intended to carry out a development such that the influence of register differences on the image quality can be minimized reliably and to a great extent. This is achieved by a number of individual values of the register values () being measured and an average value (&#x2032;) being determined from these and brought into alignment with the average value (&#x2032;) from at least one further color printing unit (&#x2032;&#x2033;).

Method and apparatus for minimizing the influence of register differences

Detection of crosstrack aberrations of registration marks in order to prevent color errors during multicolor printing. The detection of crosstrack aberrations of registration marks is with a single sensor which detects each triangle as a registration mark per color selection, whereby the triangles are each assigned a color of the multicolor printing. Sensor values are detected and formed from these differential values.

Method and device for detecting and correcting chromatic aberrations in multicolor printing

Setting registration, with detection of the entry of a printing substrate ( ) into a printing machine ( ) and calculation of the beginning of digital production of color separations ( ) to achieve an in-register position of the color separation prints ( ) on a printing substrate ( ). This is achieved by the printing substrate ( ) being detected before it enters the printing machine ( ) and, following this detection, the relative positions of the color separations ( ) being calculated, and by precise detection of the leading edge ( ) of the printing substrate ( ) being performed as it enters the printing machine ( ) and being made the basis for determining the starts of the production of the color separations ( ), their relative position having been precalculated.

Method and apparatus for setting registration in a printing machine

A method and apparatus for setting register on a multicolor printing machine ( ) having color printing units ( ) allocated to various printing inks and having image cylinders ( ), equipment ( ) for producing images, in particular electrostatic latent images, on the image cylinders ( ), a carrier ( ) for printing substrates ( ) and image transfer points ( ) for the transfer of the color separations ( ) from the color printing units ( ) to the printing substrates ( ), an allocation of the image productions ( ) on the image cylinders ( ) to the printing substrates ( ) being carried out in order to achieve coincidence of register of the color separations ( ) in the print. This is achieved by a time-independent allocation of the positions of the image productions ( ) on the image cylinders ( ) to the printing substrates ( ) being carried out for at least one defined area ( ) of all the color separations ( ).

Method and apparatus for setting register on a multicolor printing machine by time independent allocation of positions of image productions to printing substrates

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Luetjenburg, Germany

Ralph Petersen