Method of printing printed products using printing nozzles without defects and defective nozzles that have been compensated for

US11752760B2 · kind B2 · utility

Assignee

• Heidelberger Druckmaschinen AG · DE

Inventors

• Ralf Tita · Hirschhorn, DE
• Hans Köhler · Edingen-Neckarhausen, DE

Key dates

• Filing date: Jan 19, 2023
• Grant date: Sep 12, 2023
• Expiry date: Jan 19, 2043

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N1/4078
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A method of printing improved printed products using defect-free printing machine nozzles and compensated defective nozzles includes printing products and a test chart with test fields onto a transported substrate, the test fields having tonal values, every test field including an unprinted line from a nonactivated, nonprinting nozzle compensated by a neighboring nozzle having a compensation value, pairs of tonal value and compensation value being specified and used for the chart, recording an image of the chart, computer-analyzing the image and determining the compensation value. Every pair of tonal value and compensation value is used multiple times in the chart and a corresponding number of spaced apart test fields is created. A characteristic value representing test field homogeneity and determining compensation value quality is assigned to every measuring field. The best characteristic value regarding a specified criterion and the compensation value is determined for every tonal value.