Heidelberger Druckmaschinen Ag

Joerg Schmitt

Nikolaus Pfeiffer

A method for closed-loop color control in printing machines using a computer includes initially coating a printing substrate with opaque white to set up closed-loop color control in the course of a print job, subsequently applying process colors and, in the process, color measurement strips onto the opaque white, recording the opaque white and the color measurement strips using a measuring device, and, based on data recorded by the measuring device, performing closed-loop color control for process colors and opaque white using the computer. The measuring device is an inline measuring device and is initially calibrated at a fixed position of the printing substrate, then the application of opaque white is adjusted and, when a deviation stays below a maximum deviation, closed-loop control of both the opaque white and the process colors is done using the computer by taking measurements in the color control strip.

Method for inline opaque white control in printing machines

A method monitors a color standard for a machine for processing printing material. The color standard results from various parameters of the printing operation and correspondingly associated set points. The color standard may be modified and individually adapted to every machine. The machine is equipped such that current values of the parameters of the color standard are measured and forwarded to a computer. The computer compares these values and predefined set points of the color standard, and based on this information, makes an assessment of the color and quality level achieved in the printing operation. The computer outputs control signals based on the monitoring. The control signals influence the machine control and/or the determining of the current values of the parameters of the color standard in a feedback loop. The color standard is modifiable by the operator by a different selection and weighting of the parameters and the set points.

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Seeheim-Jugenheim, Germany

Joerg Schmitt