Hewlett-packard Development Company, L.p.

Hector Gomez Minano

Jan Morovic

Peter Morovic

Sergio Etchebehere Juan

Rafael Ulacia Portoles

Francisco Gomez

Alejandro Mielgo Barba

Jose Miguel Felguera

Jordi Arnabat Benedicto

Javier Maestro Garcia

Marcos Casaldaliga Albisu

Jordi Sender Beleta

Peter Norovic

Joan Jordi Coll Sicluna

Systems, apparatuses, and methods may provide for technology to control the printing of halftoning screen signatures for various levels of prints. For example, such prints may include regular edition prints or limited edition prints. During printing, a first halftoning screen is associated with one or more of the regular edition prints and a second halftoning screen is associated with the limited edition print, in some implementations. The second halftoning screen has a spatial frequency that is substantially the same as the first halftoning screen while having a spatial signature different from the first halftoning screen. Additionally, the second halftoning screen further may have spectral properties that are substantially the same as the first halftoning screen. During printing, two different printed copies of an image are formed using the first halftoning screen and the second halftoning screen.

Custom halftone for limited edition prints

Certain examples described herein relate to adjusting a printing system. In certain cases, a lookup table, LUT, is obtained where the lookup table comprises a plurality of nodes that map a plurality of input first color space values to a plurality of Neugebauer Primary area coverage, NPac, vectors in a second color space and each NPac vector comprises at least one Neugebauer Primary, NP. Each NPac vector in the LUT is adjusted by the determination of a colorimetric value of the NPac vector and the modification of the NPac vector based on a characteristic of the corresponding at least one NP and the colorimetric value such that the modification is specific to the NPac vector. The lookup table is updated with the modified NPac vector and stored for referral by the printing system in any future printing.

Color calibration in a printing system

A method is described in which sets of corresponding colorimetric values are obtained. In a set, a colorimetric value is associated with a device color. A number of device colors are selected according to the color differences between colorimetric values associated with the same device color. A color calibration pattern is elaborated for a printer to be calibrated using the selected device colors and calibration is performed using the sets of colorimetric values.

Printer calibration with colors selected according to color differences between corresponding colormetric values

A method is described in which a reflection is obtained of a laser light pattern reflected from a substrate. A reflection of diffuse light may be obtained from the substrate. A first parameter may be determined, relating to the substrate from the reflected laser light pattern. A second parameter may be determined, relating to the substrate from the reflected diffuse light and a characteristic of the substrate may be determined from the first and second parameters. A print apparatus and a machine-readable medium are also disclosed.

Determining a characteristic of a substrate

A print calibration system comprising a printing device to apply print material to a print target in a printing process, a memory for storing a lookup table; and a processor. The processor causes the printing device to print calibration points for reproducing a color ramp, by receiving a plurality of Neugebauer Primary area coverage ('NPac') points representing the plurality of calibration points and determining a hue angle and color space based on the NPac points. A plurality of nodes distributed between a first node and a second node of a sectional representation of the NPac points is determined. A lookup table is generated based on a relationship between the plurality of nodes and the NPac points for use during the printing process, wherein the lookup table comprises values to map between a first color space and a second color space, the lookup table is then provided to the printing device.

Print calibration system and method

Certain examples described herein relate to color calibration. In certain cases, a plurality of test patches are printed with a printing system, the test patches corresponding to a set of initial color sample points and a set of test colors. Color properties of the printed test patches are measured. In certain examples, a gamut descriptor is identified from a plurality of gamut descriptors using the color properties of the test colors. Each gamut descriptor defines a set of up-sampling parameters for a particular color gamut. Measured color properties for the initial color sample points are up-sampled using the set of up-sampling parameters for the identified gamut descriptor to generate up-sampled data. In certain cases, the up-sampled data is used to generate a color mapping to be applied to print job data received by the printing system.

Color calibration

A method of obtaining a calibration factor for color calibration of a printing system. The method includes printing, using the printing system, a plurality of Neugebauer primaries (NPs) each defined by a respective Neugebauer primary area coverage (NPac) vector. For each of the NPs, an area coverage change of the NP is determined from a measurement of a visual property for the NP and a measurement of the visual property for a corresponding reference NP corresponding to the respective NPac vector. The calibration N factor for the printing system is obtained based on the area coverage change for respective NPs of the plurality of NPs.

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

A method of calibrating a printing system. Data defining a color mapping that maps a first set of n-dimensional color Input points to a corresponding second set of n-dimensional color output points, the color mapping representing a measured behavior of the printing system, is obtained. A smoothed mapping function of color input points that satisfies a predetermined optimization condition based on a mapping error between the smoothed mapping function and the color mapping is determined. The mapping error is a function of individual errors between outputs of the smoothed mapping function as applied to respective color input points in the first set of color input points and corresponding color output points from the second set of color output points as mapped from the respective color input points by the color mapping. The smoothed mapping function is used to calibrate the printing system.

An apparatus and method for use in generating calibration parameters for a printing apparatus comprising a plurality of print modules are disclosed. The method comprises printing a first plurality of test patches for each print module of the plurality of print modules, analysing the first plurality of test patches to identify at least two clusters of print modules, wherein each cluster comprises a sub-group of print modules having substantially similar performance, printing a second plurality of test patches comprising an extended calibration test patch set for each cluster of print modules, the second plurality of test patches being distributed across the print modules of the cluster, and analysing extended calibration test patch set for each cluster to determine a calibration parameter for the printing apparatus.

Multi-module printer calibration

The present invention is directed at a printhead cleaning assembly, comprising: a frame; a wipe cartridge receptacle mounted on the frame, the receptacle being movable relative to the frame between a first receptacle position and a second receptacle position; a wipe cartridge fixing latch, mounted on the wipe cartridge receptacle, wherein the latch is movable between a closed position and an open position, wherein the latch is coupled to a lock/unlock mechanism that moves the latch between the closed position and the open position in response to a movement of the receptacle between the first receptacle position and the second receptacle position.

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Sant Cugat del Valles, Spain

Hector Gomez Minano