Heidelberger Druckmaschinen Ag

Peter Weinholz

Bernd Stritzel

Frank Gnutzmann

Uwe-Jens Krabbenhoeft

Boris Von Neindorff

Volkmar Funke

Eike Siemsen

A method for inkjet printing machine color control includes color transformation of print data from first color space to process color space in a first stage using a computer transforming print data from the first to an intermediate color space while keeping special colors, and a second stage transforming corrected print data including special colors from intermediate to process color space. The computer uses print data corrected after the first stage as second stage starting values. Print data transformed into the process color space are printed. First color space corresponds to CMYK, flexographic printing or RGB color space with special colors, intermediate color space corresponds to CMYK color space with special colors, process color space corresponds to CMYK color space with additional process colors. The computer corrects CMY, not K print data or special not transformed colors, when correcting print data in the intermediate color space after the first stage.

Method for controlling ink in an inkjet printing machine by simulating the film thickness of CMY inks

A method for preserving the black composition of at least one object positioned to overprint a special color in a print image for preprint color management of a printing operation using a computer, includes transforming the special color and the object into a combination of process colors of the printing operation during the color management process and then using this combination of process colors to generate the print image in a printing machine. The color transformation into the process colors of the printing operation is achieved in two stages. In a first stage, the color transformation into the process colors is carried out while keeping the special colors, then checking if the object is overprinted onto the special color, then removing the black proportion of the object and then in a second stage, transforming the special color into the process colors and subsequently maximizing the black proportion of the object.

Method for preserving the black composition of objects

The method generates trapping contours on color edges in a page to be printed that is defined in digital data. The trapping contours reduce the defects that are caused by register errors in the printing machine. The method operates similarly to a filter, using a window that is moved over the entire page, picture element by picture element. Certain neighboring picture elements of the central element are selected and used for calculating a trapping color. The color separation proportions of the central picture element are compared with the corresponding color separation proportions of the trapping color. The result of the comparison determines which color separation proportions of the central picture element are to be changed.

Method for generating trapping contours in a print page

A method for compressing digital image data present as matrix of M&times;N pixels, to a reduced data set, includes dividing the matrix of M&times;N pixels into blocks of u&times;v pixels, classifying the blocks of u&times;v pixels into blocks containing only pixels of one block color or single-color blocks, blocks containing pixels of a foreground color and pixels of a background color or two-color blocks, and blocks containing pixels with more than two colors or multicolor blocks, and coding, in the image data of the single-color blocks and the two-color blocks, by command code words and data words, pixel patterns which are repeated in at least one manner selected from the group consisting of from block to block and within a block, respectively.

Growing community of inventors

Tuettendorf, Germany

Peter Weinholz