摘要:
In a process for assessing the quality of a print image produced on a printing material in a multi-color printing process, in which signals which reproduce print-image elements are generated with an image-recording arrangement, in which color values are derived from the signals for every print-image element, in which the color values are transformed into color measures of a predetermined color space, in which color distances between an actual color site and a desired reference color site are determined for the print-image elements, correction variables of the control elements (18, 19, 20, 21), whose effect on a control element (18) would cause the actual color sites to be as close as possible to the reference color sites, are calculated from the color distances and stored in memory, that the color-distance vectors (.DELTA.L.sub.Bn, .DELTA.a.sub.Bn, .DELTA.b.sub.Bn) and color distances (.DELTA.E.sub.Bn) of at least one predetermined reference image (B.sub.n) with homogeneous area coverage are determined as a measure for the quality in the said print-image region, the correction variables (.DELTA.s.sub.B, .DELTA.s.sub.C, .DELTA.s.sub.M, .DELTA.s.sub.Y) which are necessary for compensation of the color distances (.DELTA.E.sub.Bn) in the reference image (B.sub.n) corresponding to the previously calculated and stored correction variables.
摘要:
A method is proposed for generating a color profile using the determination of a mapping A′ of a device-independent process space Q(m) of dimension m, m being a natural number, to a device-dependent process space K′(n) of dimension n, n being a natural number, for a first set of specific parameters, which is distinguished by the mapping being represented by a concatenation of mappings, which includes a known mapping A from Q(m) to a device-dependent process space K(n) of dimension n, n being a natural number, for another set of specific process parameters, which differs at least in one element from a first set of specific process parameters; and either of a mapping TK from K(n) to K′(n) or a self-mapping TQ by Q(m).
摘要:
To obtain colorimetric values intended for regulating inking on a printing press (1) from a printed image (3) produced by the printing press (1), the printed image is measured calorimetrically in a plurality of pixels (4) with respect to a selected color coordinate system. The color vectors thus obtained for each pixel (4) are used to calculate color difference vectors to predetermined reference color vectors based on the same color coordinate system or reference color vectors determined from a reference printed sheet (3). The color difference vectors are multiplied by a weighting factor determined from the ink coverage of the pixels (4) and/or the color differences between the pixels (4) and their neighboring pixels (4). The color difference vectors weighted in this way can then be used as colorimetric values for regulating the inking on the printing press (1).
摘要:
For determining the ink coverages of printing inks involved in printing in one pixel of a print image, the pixel is scanned photoelectrically in the visible range of the spectrum and also in the near infrared range. Color coordinates of a perceptually approximately equidistant color system and at least one infrared value are formed from the scanned signals thus obtained. The ink coverages of the printing inks involved in the printing are then calculated from these color coordinates and from the minimum of one infrared value and are allocated to the pixel.
摘要:
In order to control ink application in a printing press, a sheet (3) printed by the printing press (1) is colorimetrically measured in a number of pixels (4) with respect to a selected color coordinate system that has been expanded to be four-dimensional by also taking into account an infrared component. Color difference vectors with respect to the desired color vectors, predefined or determined from a reference sheet (3) and referred to the same color coordinate system, are computed from the color vectors obtained for each pixel (4). A sensitivity matrix is determined for each measured pixel (4) of the sheet (3). The pixels (4) are classified by sensitivity class. The color difference vectors and sensitivity matrices of the pixels (4) pertaining to the same sensitivity class are averaged for each sensitivity class, and input parameters, in particular film thickness modification vectors, are computed from the averaged color difference vectors and averaged sensitivity matrices of all sensitivity classes for a control unit (9) of the inking mechanisms of the printing press (1). The inking of the printing press (1) is then controlled on the basis of the input parameters thus computed.
摘要:
Method for zonally controlling and regulating inking in a printing machine having a plurality of printing units includes photo-electrically measuring, at least at one location of each inking zone, a printed product provided in the printing machine, determining an actual color locus from the measurements, comparing the determined actual color locus with a prescribed setpoint color locus of the respective location and, in the event of a spacing between the compared color loci, calculating corrective control data for inking elements of the printing machine and transmitting the control data to the printing units so as to minimize the spacing between the actual and setpoint color loci, the actual color locus meeting tolerance requirements by lying within a prescribed color tolerance and within a permissible region at a setpoint color locus characterized by an absence of color change; and device for performing the method.
摘要:
Operation of printing presses can typically require that various printing jobs be performed consecutively, or that is, one printing job may need to be performed immediately after a previous printing job is completed. Such printing operations can preferably be conducted, without a complete shutdown of the press, by providing a transitional, or changeover operation during which the various settings for the printing press can be changed from the previous settings to settings needed for the subsequent printing job.
摘要:
Method of regulating inking when printing is performed with more than three printing colors, which includes comparing, in a control, actual value color locations derived from a color measuring arrangement with reference value color locations in a given user color space; deriving control signals from the attained comparison values, in accordance with a predetermined relationship, for an inking device containing ink distribution devices which influence the thickness of a layer of printing ink applied zonally in the form of halftone dots or solid full-tone areas to a material to be printed; and further deriving the actual value color locations from measurement locations in the printed image. When printing with n printing colors wherein n is greater than 3, deriving the actual value color locations from measurement locations of at least (n-2) regions, wherein vectors of area coverage of all of the n printing colors involved are, respectively, linearly independent of one another.
摘要:
A color measurement on printed materials produced by a printing press is performed by at least a first color measuring device installed in the printing press and at least a second color measuring device. A signal is output by the first color measuring device in the printing press when the measured color values registered on the printing materials are located within a predefined tolerance limit for a predefined period and that, after the signal has been output, a color measurement on one of the printed materials thus produced is performed with the second color measuring device.
摘要:
The invention relates to a trimming strip for the shaping of cigarettes and/or filters, comprising at least one warp thread and several weft threads. The at least one warp thread comprises several fibres made from a liquid crystal polymer and at least one further fibre which has a greater roughness than the fibre made from liquid crystal polymer.