Hewlett-packard Development Company, L.p.

Jordi Sender Beleta

Jan Morovic

Peter Morovic

M Isabel Borrell Bayona

Marti Rius Rossell

Marcos Casaldaliga Albisu

Montserrat Solano Pallarol

Joshua A Mann

Alejandra Terron Arregui

Hector Gomez Minano

Maria Isabel Borrell Bayona

Xavier Bruch Pla

MIsabel Borrell Bayona

Montserrat Sorano Pallarol

Peter Norovic

Isabel Borell Bayona

A method of detecting printing fluid mixing is provided. A test pattern for at least one printing fluid is printed with a printing device. The test pattern for the at least one printing fluid is scanned with a scanning device. Colorimetric data of the test pattern for the at least one printing fluid are obtained. Metric values are determined from the colorimetric data. A statistical analysis is performed on the determined metric values. Based on the statistical analysis, it is determined whether printing fluid mixing has occurred and where printing fluid mixing has occurred.

Print pattern and algorithm for automatic ink mix detection

Certain examples described herein relate to evaluating print quality. In these examples, a check image is printed at a first print quality in accordance with test image data for at least one test image, and a reference image is printed at a second print quality with reference image data corresponding to the one or more test images modified to simulate one or more print defects. A comparison of the printed reference image and the printed check image allows evaluation of a quality level for the printed check image.

Print quality evaluation

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.

Adjusting a drive signal to compensate for a difference between pattern portions

The present disclosure discloses a page wide array (PWA) printer () particularly but not exclusively for performing print jobs while maximizing print bar performance uniformity within the printer. The PWA printer includes a print bar which can be moved laterally and a controller which causes the print bar to laterally move from a first to a second position and causes the nozzles within the print bar to print an image while the print bar is in the second position without modifying the lateral alignment of the image.

Page wide array printer

A method and system of controlling at least one printbar in a printing system are described. The printing system has one or more of printbars distributed along a media transport. A first image including a reference pattern is generated on a print medium with a first printbar. A pattern is then detected on the print medium. The reference pattern and the detected pattern are used to determine a position of the first image relative to a second printbar. This position is used to configure nozzle data for a second image to be generated on the print medium by the second printbar.

Printing system control

A method of generating a diagnostic plot for a printing system includes printing a first half of a diagnostic pattern representative of a first state of the printing system, and printing a second half of the diagnostic pattern representative of a second state of the printing system. Variation of the diagnostic pattern from an adjacent diagnostic pattern indicates the printing system is out of specification.

Diagnostic plot for printing system

Examples include estimation of pen to paper spacing (PPS). Examples include an alignment pattern printed on a medium at a target speed, an optical scan procedure performed on the printed alignment pattern to determine values of cross-media misalignment for first and second portions of the alignment pattern, determination of a dynamic swath height error (DSHE) effect value based on the values of cross-media misalignment, and estimation of an amount of PPS based on the determined DSHE effect value and the target print speed.

Estimation of pen to paper spacing

A method and system of controlling at least one printbar in a printing system are described. The printing system has one or more of printbars () distributed along a media transport. A first image including a reference pattern (A,B) is generated on a print medium () with a first printbar (). A detector () then detects a pattern on the print medium. The reference pattern and the detected pattern are used to determine a position of the first image relative to a second printbar (). This position is used to configure nozzle data for a second image to be generated on the print medium by the second printbar.

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.

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Barcelona, Spain

Jordi Sender Beleta