DYSFUNCTIONAL EJECTION UNIT DETERMINATION IN INKJET PRINTING

• Main Author: GERRITS, Carolus E.P
• Format: Patent
• Language: English; French; German
• Published: 28.02.2024
• Subjects: CORRECTION OF TYPOGRAPHICAL ERRORS; i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; LINING MACHINES; PERFORMING OPERATIONS; PRINTING; SELECTIVE PRINTING MECHANISMS; STAMPS; TRANSPORTING; TYPEWRITERS

The present invention relates to a method for establishing a list of dysfunctional ejection units, i.e. a list of ejection units in an inkjet printer that are to be discarded during printing of image data in order to obtain a better print quality. The method comprises the steps of: printing and scanning a first test pattern (9) wherein individual dots of a single ejection unit can be discerned; printing and scanning a second test pattern (8) with uniform grayscale areas that are processed in a similar way as image data; determining a drop ejection characteristic of a single ejection unit from the scanned first test pattern; determining an optical profile of the second test pattern in a direction of the array; composing a list of ejection units that yield dots outside a predetermined range; adding to the list the ejection units that show a deviating optical density compared to their direct environment, and passing the list of ejection units to the printer control software as a list of dysfunctional ejection units.