The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 31, 2020
Filed:
Feb. 11, 2019
Heidelberger Druckmaschinen Ag, Heidelberg, DE;
Johannes Muehl, Ennepetal, DE;
Hans Koehler, Edingen-Neckarhausen, DE;
Roland Stenzel, Heidelberg, DE;
Andreas Henn, Neckargemuend, DE;
Martin Mayer, Ladenburg, DE;
Steffen Neeb, Bensheim, DE;
Frank Muth, Karlsruhe, DE;
Jan Krieger, Heidelberg, DE;
Nicklas Raymond Norrick, Heddesheim, DE;
Mina Abosetta, Mannheim, DE;
Heidelberger Druckmaschinen AG, Heidelberg, DE;
Abstract
A method for detecting defective printing nozzles in an inkjet printing machine includes printing a multi-row printing nozzle test chart formed of horizontal rows of equidistant vertical lines periodically underneath one another, with only printing nozzles in a print head contributing to every row of the test chart corresponding to the horizontal rows. An area coverage element geometrically associated with the test chart is printed, both elements are recorded by an image sensor and analyzed by the computer. The computer analyzes the recorded area coverage element to detect print defects and allocates defects to a region of geometrically close printing nozzles. An analysis of the test chart in the region identifies nozzles causing the defect. Defective printing nozzles are detected based on thresholds, the detected printing nozzles are then compensated, and in the analysis of the recorded area coverage element, influences of the sensor are eliminated by shading correction.