US 11,752,775 B2
Method for determining print defects in a printing operation carried out on an inkjet printing machine for processing a print job
Jan Krieger, Heidelberg (DE); and Frank Schumann, Heidelberg (DE)
Assigned to Heidelberger Druckmaschinen AG, Heidelberg (DE)
Filed by HEIDELBERG DRUCKMASCHINEN AG, Heidelberg (DE)
Filed on Jan. 13, 2020, as Appl. No. 16/740,687.
Claims priority of application No. 19151348 (EP), filed on Jan. 11, 2019.
Prior Publication US 2020/0223230 A1, Jul. 16, 2020
Int. Cl. B41J 2/21 (2006.01); B41J 29/393 (2006.01)
CPC B41J 2/2142 (2013.01) [B41J 2/2139 (2013.01); B41J 2/2146 (2013.01); B41J 29/393 (2013.01); B41J 2029/3935 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for determining print defects in a printing operation carried out on an inkjet printing machine for processing a print job, the method comprising the following steps:
using a camera system to record and digitize printed products generated during the printing operation;
feeding a camera image generated in the camera system to a detection algorithm on a computer, using the detection algorithm to separate color separations of the camera images, detect the print defects in the color separations, link images of individual color separations to form a candidate image, filter the candidate image, enter remaining detected print defects into a list, and forward the list to a machine control unit of the printing machine;
alerting the machine control unit when print defects are found; and
ejecting a printed product by using a waste ejector if necessary.