Abstract: A print apparatus calibration method is disclosed. The method comprises printing, from each of a plurality of dies of a print head onto a printable substrate, an image in a first color according to a calibration pattern and an image in a second color according to the calibration pattern, the calibration pattern comprising a plurality of patches having a plurality of different densities. The method may comprise scanning, using a scanning unit, the images formed on the printable substrate to generate scanned image data, wherein the images in the first color are scanned by a first scanning module of the scanning unit and the images in the second color are scanned by a second scanning module of the scanning unit. The method may comprise analyzing, using processing apparatus, the scanned image data to identify any differences between printed densities of corresponding patches in different images of the same color. The method may comprise performing a calibration based on the analysis.

Abstract: In an example, a print system includes a redundancy engine, a separation engine, and a print engine. In that example, the redundancy engine may identify a group of nozzles based on a redundancy characteristic of a plurality of print head nozzles of a print head to be received at the print head station and the separation engine may select a color separation operation corresponding to a drop domain associated with the group of nozzles identified by the redundancy engine to operate the print head with redundancy. In that example, the print engine may generate instructions using the selected color separation operation to cause the print head to eject print fluid from a combination of nozzles corresponding to the group of nozzles based on the drop domain to operate the print head with a redundancy print mode.

Abstract: Certain examples describe a method of calibrating a printer and a printing system. An interferential pattern is printed in the form of a print calibration image on a print medium. Data representative of the interferential pattern as printed on the print medium is detected using an optical sensor. The printer is calibrated based on the captured data. The interferential pattern is based on a waveform that varies in amplitude along an axis perpendicular to a printing axis under calibration and has repeated sets of multiple patterns based on the waveform, the repeated sets having a varying pattern spacing in the printing axis under calibration.

Abstract: Certain examples describe a method of calibrating a printer and a printing system. An interferential pattern is printed in the form of a print calibration image on a print medium. Data representative of the interferential pattern as printed on the print medium is detected using an optical sensor. The printer is calibrated based on the captured data. The interferential pattern is based on a waveform that varies in amplitude along an axis perpendicular to a printing axis under calibration and has repeated sets of multiple patterns based on the waveform, the repeated sets having a varying pattern spacing in the printing axis under calibration.

Abstract: A computing device receives first data indicating a first metric of a first printed test area and second data indicating a second metric of a second printed test area. The first printed test area is associated with a first plurality of Neugebauer Primaries and each Neugebauer Primary in the first plurality of Neugebauer Primaries is associated with a respective area coverage in the first printed test area. The second printed test area is associated with a second plurality of Neugebauer Primaries, wherein each Neugebauer Primary in the second plurality of Neugebauer Primaries is associated with a respective area coverage in the second printed test area and the second plurality of Neugebauer Primaries is different from the first plurality of Neugebauer Primaries. The computing device generates third data associating a color in a color space with the first plurality of Neugebauer Primaries or the second plurality of Neugebauer Primaries in dependence on the first metric and the second metric.

Abstract: A computing device receives first data indicating a first metric of a first printed test area and second data indicating a second metric of a second printed test area. The first printed test area is associated with a first plurality of Neugebauer Primaries and each Neugebauer Primary in the first plurality of Neugebauer Primaries is associated with a respective area coverage in the first printed test area. The second printed test area is associated with a second plurality of Neugebauer Primaries, wherein each Neugebauer Primary in the second plurality of Neugebauer Primaries is associated with a respective area coverage in the second printed test area and the second plurality of Neugebauer Primaries is different from the first plurality of Neugebauer Primaries. The computing device generates third data associating a color in a color space with the first plurality of Neugebauer Primaries or the second plurality of Neugebauer Primaries in dependence on the first metric and the second metric.

Abstract: In an example, a print system includes a redundancy engine, a separation engine, and a print engine. In that example, the redundancy engine may identify a group of nozzles based on a redundancy characteristic of a plurality of print head nozzles of a print head to be received at the print head station and the separation engine may select a color separation operation corresponding to a drop domain associated with the group of nozzles identified by the redundancy engine to operate the print head with redundancy. In that example, the print engine may generate instructions using the selected color separation operation to cause the print head to eject print fluid from a combination of nozzles corresponding to the group of nozzles based on the drop domain to operate the print head with a redundancy print mode.

Abstract: In some examples, a printer determines a difference between an enlarged calibration pattern portion printed on a substrate by a first portion of a nozzle array of the printer and an enlarged reference pattern portion printed on the substrate by a second portion of the nozzle array, the enlarged calibration pattern portion produced by printing respective smaller calibration pattern portions at corresponding different relative positions between the nozzle array and the substrate, and the enlarged reference pattern portion produced by printing respective smaller reference pattern portions at corresponding different relative positions between the nozzle array and the substrate. The printer adjusts at least one drive signal to at least one of the first portion of the nozzle array and the second portion of the nozzle array to compensate for the determined difference.

Abstract: A method of controlling a printer to print a pattern using a number of print head dies, each print head die including a number of nozzle trenches wherein each one of the number of nozzle trenches is associated with a different color, wherein the nozzles of neighboring dies overlap in respective overlap zones, the method comprising applying masks to the nozzles of neighboring dies in the respective overlap zones to distribute, in the overlap zones, the pattern to be printed between the nozzles of the respective neighboring dies, wherein the masks, in the overlap zones, retain the order in which the nozzles of selected nozzle trenches associated with a selected one of the colors are fired.

Abstract: A method of controlling a printer to print a pattern using a number of print head dies, each print head die including a number of nozzle trenches wherein each one of the number of nozzle trenches is associated with a different color, wherein the nozzles of neighboring dies overlap in respective overlap zones, the method comprising applying masks to the nozzles of neighboring dies in the respective overlap zones to distribute, in the overlap zones, the pattern to be printed between the nozzles of the respective neighboring dies, wherein the masks, in the overlap zones, retain the order in which the nozzles of selected nozzle trenches associated with a selected one of the colors are fired.

Abstract: A calibration target is disclosed. The calibration target is created such that a color patch is sensitive to drop weight changes based on drop weight variations that show greater changes in color for a given change in drop weight.

Abstract: A calibration target is disclosed. The calibration target is created such that a color patch is sensitive to drop weight changes based on drop weight variations that show greater changes in color for a given change in drop weight.

Abstract: A calibration target is disclosed. The calibration target is created such that a color patch is sensitive to drop weight changes.

Abstract: In some examples, a printer determines a difference between an enlarged calibration pattern portion printed on a substrate by a first portion of a nozzle array of the printer and an enlarged reference pattern portion printed on the substrate by a second portion of the nozzle array, the enlarged calibration pattern portion produced by printing respective smaller calibration pattern portions at corresponding different relative positions between the nozzle array and the substrate, and the enlarged reference pattern portion produced by printing respective smaller reference pattern portions at corresponding different relative positions between the nozzle array and the substrate. The printer adjusts at least one drive signal to at least one of the first portion of the nozzle array and the second portion of the nozzle array to compensate for the determined difference.

Abstract: A calibration-pattern printing method in a page-wide array printer having an array of print nozzles extending in a transverse direction of the printer comprises printing a respective calibration pattern portion on a substrate by at least one first portion of the nozzle array, changing the relative position of the nozzle array and substrate in the transverse direction then printing a respective further calibration pattern portion on the substrate by the at least one first portion of the nozzle array so that a given first nozzle-array portion prints a calibration pattern portion and further calibration pattern portion that are at least partially aligned with each other in the longitudinal direction and join up in the transverse direction to form an enlarged calibration pattern portion.

Abstract: A calibration target is disclosed. The calibration target is created such that a color patch is sensitive to drop weight changes.

Abstract: A calibration-pattern printing method in a page-wide array printer having an array of print nozzles extending in a transverse direction of the printer comprises printing a respective calibration pattern portion on a substrate by at least one first portion of the nozzle array, changing the relative position of the nozzle array and substrate in the transverse direction then printing a respective further calibration pattern portion on the substrate by the at least one first portion of the nozzle array so that a given first nozzle-array portion prints a calibration pattern portion and further calibration pattern portion that are at least partially aligned with each other in the longitudinal direction and join up in the transverse direction to form an enlarged calibration pattern portion.