Printer and computer-implemented process for controlling a printer

A printer including

• a number of print heads extending across a print zone, each print head including at least one nozzle array extending in a direction of a print head axis, each nozzle array comprising a center section of nozzles and side sections of nozzles, wherein the side sections of neighboring nozzle arrays overlap defining an overlap region and the center sections of the neighboring nozzle arrays define non-overlap regions;
• a scanning device mounted on a carriage for scanning across a print medium;
• and
• a printer controller, the printer controller including instructions to:
• drive the print heads to print a test pattern using the neighboring nozzle arrays, the test pattern comprising an interferential-type pattern printed by the side sections of the neighboring nozzle arrays in the overlap region and a reference pattern printed by the center sections of the neighboring nozzle arrays in the non-overlap region, wherein the reference pattern includes reference images simulating alignment states;
• drive the scanner to scan the printed test pattern;
• compare with each other characteristics of the scanned test pattern in the overlap region and the non-overlap region;
• and
• derive alignment information from the comparison.

A method of controlling a printer, the printer including a number of print heads extending across a print zone, each print head including at least one nozzle array;

• the method comprising:
• printing a reference pattern;
• printing a test pattern, the test pattern comprising an interferential-type pattern printed by neighboring nozzle arrays of said print heads in an overlap region;
• wherein the reference pattern comprises at least one of:
• an image simulating the interferential-type pattern when printed in the overlap region when the neighboring nozzle arrays are in a nominal position;
• and
• an image simulating the interferential-type pattern when printed in the overlap region when the neighboring nozzle arrays are misaligned relative to each other;
• scanning the printed images resulting from the test pattern;
• comparing with the reference pattern the printed image resulting from the test pattern;
• and deriving alignment information from the comparison.