Test pattern for compensating for a lateral offset in the detection of an impaired nozzle

A method for detecting an impaired nozzle of a print head of an inkjet printing device, wherein the print head comprises K nozzles, with K>10, that are designed to print corresponding K dots in corresponding K columns of a line of a print image onto a recording medium, the method comprising

• printing a test pattern by the print head onto the recording medium, the test pattern comprising a matrix with matrix points, wherein
• the matrix of matrix points has K columns for the corresponding K nozzles and N rows, with N>1;
• the test pattern has a respective sequence of N matrix points in each of the K columns, of which N matrix points one or more are printed matrix points and one or more are non-printed matrix points;
• a printed matrix point in a defined column and in a defined row indicates that the nozzle corresponding to the defined column prints a dot upon printing the defined row of the test pattern;
• a non-printed matrix point in the defined column and in the defined row indicates that the nozzle corresponding to the defined column does not print a dot upon printing the defined row of the test pattern;
• and
• the sequences of N matrix points in the K columns differ from one another such that a lateral offset of up to ±V columns of the test pattern can be detected and compensated for, with V≥1;
• recording sensor data with regard to the test pattern printed onto the recording medium;
• and
• detecting an impaired nozzle of the print head on the basis of the sensor data.

An inkjet printing device, comprising:

• a print head comprising K nozzles, with K>10, the K nozzles designed to print corresponding K dots in corresponding K columns of a line of a print image onto a recording medium;
• a sensor unit configured to acquire sensor data with regard to the print image printed onto the recording medium;
• and
• a control unit comprising a processor configured to:
• instruct the print head to print a test pattern onto the recording medium, the test pattern comprising a matrix with matrix points, wherein
• the matrix of matrix points has K columns for the corresponding K nozzles and N rows, with N>1;
• the test pattern has a respective sequence of N matrix points in each of the K columns, of which N matrix points one or more are printed matrix points and one or more are non-printed matrix points;
• a printed matrix point in a defined column and in a defined row indicates that the nozzle corresponding to the defined column prints a dot upon printing the defined row of the test pattern;
• a non-printed matrix point in the defined column and in the defined row indicates that the nozzle corresponding to the defined column does not print a dot upon printing the defined row of the test pattern;
• and
• the sequences of N matrix points in the K columns differ from one another such that a lateral offset of up to ±V columns of the test pattern can be detected and compensated for, with V≥1;
• record the sensor data with regard to the test pattern printed onto the recording medium from the sensor unit;
• and
• detect an impaired nozzle of the print head based on the sensor data.