US 11,724,516 B2
Failing nozzle compensation and non-uniformity correction in inkjet printing
Arnoldus Theodorus Steenkamer, Boxmeer (NL); Tom Tilly Norbert Lebouille, Boxmeer (NL); and Petrus Leonardus Johannes Welten, Boxmeer (NL)
Assigned to SPGPrints B.V., Boxmeer (NL)
Appl. No. 17/607,535
Filed by SPGPrints B.V., Boxmeer (NL)
PCT Filed May 27, 2020, PCT No. PCT/EP2020/064669
§ 371(c)(1), (2) Date Oct. 29, 2021,
PCT Pub. No. WO2020/239820, PCT Pub. Date Dec. 3, 2020.
Claims priority of application No. 2023206 (NL), filed on May 27, 2019.
Prior Publication US 2022/0219463 A1, Jul. 14, 2022
Int. Cl. B41J 29/393 (2006.01); B41J 2/21 (2006.01); G06K 15/02 (2006.01)
CPC B41J 2/2139 (2013.01) [B41J 2/2142 (2013.01); G06K 15/027 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for detecting one or more failing nozzles in an inkjet printhead of an inkjet printer for printing an image on a substrate and compensating failing nozzles, as well as for correcting colour uniformity of a printed image in inkjet printing an image on a substrate,
which method comprises:
a first printing step of printing a first test pattern on a test substrate having a receiving layer adapted to the nature of the inkjet ink by jetting inkjet ink from an inkjet printhead of the inkjet printer, wherein each nozzle of the inkjet printhead is controlled to print at least one line;
a first scanning step of scanning the printed first test pattern using a scanner having a resolution at least equal to that of the inkjet printhead, thereby obtaining a first test pattern scan of the printed first test pattern;
a first computing step of acquiring the nozzle status of each nozzle from the first test pattern scan and determining compensation factors for failing nozzles thus identified, thereby obtaining compensated nozzle control data;
a second printing step of printing a second test pattern on a test substrate having a receiving layer adapted to the nature of the inkjet ink, by jetting inkjet ink from an inkjet printhead of the inkjet printer, which is controlled using the compensated nozzle control data, wherein the second test pattern comprises at least two areas, each area having a different greyscale;
a second scanning step of scanning the printed second test pattern using the scanner having a resolution at least equal to that of the inkjet printhead, thereby obtaining a second test pattern scan of the printed second test pattern;
a second computing step of analysing the second test pattern scan in each of the at least two areas having a different greyscale for local deviations from the greyscale of the respective area and determining correction factors for local deviations thus identified for each of the greyscales, thereby obtaining corrected nozzle control data for the respective greyscale;
wherein the second pattern also comprises at least two areas having the same greyscale, of which a first area is printed by non-neighbouring nozzles of the inkjet printhead and a second area is printed by other non-neighbouring nozzles of the inkjet printhead; and
wherein the second computing step also comprises analysing from the second test pattern scan in each of the at least two areas having the same greyscales for local deviations from the greyscale of the respective area and determining additional correction factors for local deviations thus identified for each of the greyscales, thereby obtaining additionally corrected nozzle control data for the respective greyscale.