Hewlett-Packard Development Company, L.p.

Marti Rius Rossell

Peter Morovic

Jan Morovic

Juan Manuel Garcia Reyero Vinas

Jordi Sender Beleta

M Isabel Borrell Bayona

Marcos Casaldaliga Albisu

Montserrat Solano Pallarol

Raul Rodriguez Alonso

Sergio Puigardeu Aramendia

Utpal Kumar Sarkar

Martin Urrutia Nebreda

MIsabel Borrell Bayona

Javier Maestro Garcia

Xavier Quintero Ruiz

Joan Vidal Fortia

Leticia Rubio

Ezequiel Jordi Rufes Bernad

Alex Campa Coloma

Jordi Ferran Cases

Jordi Bas Ferrer

Adria Gallart Del Burgo

Javier Gonzalez Bruno

Nuria Jornet Jaumot

Andreu Gonzalez Oliva

Utpal Kumar Sarker

Raùl Rodriguez Alonso

Leyre Hernandez Martinez

Victor Serra Fernandez

An interferential pattern is printed to a print media using an upper row die. A first portion of an additional interferential pattern is printed to a print media using a lower row die. A second portion of the additional interferential pattern is printed to the print media using the upper row die. An alignment error between the upper row die and the lower row die is determined based on interferential pattern and the additional interferential pattern.

Interferential patterns for alignment calibration of printheads

According to some examples, a skew detection device comprises a first roller rotatable around a first axis, a second roller rotatable around a second axis, a first sensor, and a second sensor. The first sensor measures a first rotation parameter from the first roller and the second sensor measures a second rotation parameter from the second roller. A movement of a print media over the device rotates the first contact roller and the second roller, and a controller determines a skew of the print media based on the first and second rotation parameters captured by the first sensor and the second sensor.

Skew detection

Certain examples described herein relate to halftone level adjustment for Neugebauer Primaries (NPs). In certain examples, halftone levels for NPs are obtained for a halftone for printing an image. It is determined whether the halftone corresponds to a line or an area fill. The halftone levels may be adjusted in response to these levels exceeding a printing attribute threshold. The printing attribute threshold may be dependent on whether the halftone corresponds to a line or an area fill. The image may then be printed using the adjusted halftone levels.

Neugebauer primaries halftone level adjustment

Example implementations provide a controller for controlling printing of a printer, the controller comprising:

Printers and controllers

A method of printing is disclosed. The printing may involve printing on a printable medium using a print head having a plurality of nozzles, the printable medium having a leading edge and a defined zone adjacent to the leading edge. The print head may be to deposit print agent onto the printable medium via the plurality of nozzles during successive printing passes. The method may comprise: during a first printing pass, depositing print agent from a subset of the plurality of nozzles onto the printable medium outside the defined zone. The method may further comprise: advancing the printable medium by a defined distance. The method may further comprise: during a second printing pass, depositing print agent from a subset of the plurality of nozzles onto the printable medium within the defined zone.

Depositing print agent

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

Certain methods of generating a color mapping are described. In one method, an output of a color halftone processing pipeline is processed so as to determine a set of Neugebauer Primary area coverage (NPac) values that are representative of the output of the color halftone processing pipeline. These NPac values are then used, together with knowledge of an original input image, to generating the color mapping.

Color mapping generation including application of a halftone operation on continuous tone color data

Methods for configuring and calibrating a printing system are described. Configuring a printing system involves obtaining data for determining a reference print element in the printing system. The reference print element is then used to determine calibration data for a given print element. The calibration data is applied for the given print element to generate a print output.

Print calibration

A printer includes a page wide array of printing elements extending in a first orientation and co-located with a media path extending in a second orientation generally perpendicular to the first orientation. The printer is selectively operable according to a calibration involving current calibration values for a first subset of the page wide array of printing elements and a substitute calibration value for at least one non-first subset printing element of the page wide array immediately adjacent to at least one of the first subset printing elements.

Printer calibration

A method of color halftone processing is disclosed. A plurality of color mappings each provide a mapping from a color value in a color space to a set of Neugebauer Primary area coverage (NPac) values in an NPac space. An imaging metric is obtained for each NPac value in the set. An NPac value in the set is selected based on the imaging metric. The selected NPac value is used as an output NPac value in a combined color mapping for the color value.

Color halftone processing with mapping color values to NPac values

A method for color mapping is disclosed. A color mapping is generated based on an imaging model and a color model for an imaging device. The imaging model allows a set of perturbations to be modelled. A set of metamers is determined for one or more colors. For each metamer, at least the imaging model is used to estimate a color output with at least one modelled perturbation. The color outputs are used to select a metamer from the set to be used for the color mapping.

Color mapping modeling printing device perturbations

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.

Growing community of inventors

Sant Cugat del Valles, Spain

Marti Rius Rossell