Hewlett-packard Development Company, L.P.

Purdue Research Foundation

Utpal Kumar Sarkar

Leticia Rubio

Xavier Quintero Ruiz

Jan Morovic

Peter Morovic

Robert Alan Ulichney

Jan Philip Allebach

M Isabel Borrell Bayona

Marcos Casaldaliga Albisu

Juan Manuel Garcia Reyero Vinas

Marti Rius Rossell

Lluis Abello Rosello

Andreas Muller

Yngvar Rossow Sethne

Xavier Farina Vargas

Jaime Fernandez

Martin Urrutia Nebreda

Salvador Sanchez Ribes

Jacint Humet Pous

Joan Vidal Fortia

Josep-Maria Serra

M Isabel Borrell

Barret Kammerzell

Carles Carmona Calpe

Jaime Fernandez Del Rio

Alex Campa Coloma

Jesús Garcia Maza

Raul Rodriguez Alonso

David Vendrell Tornero

Pablo Vidal Alvarez

Andreas Müller

Yafei Mao

Juan Manuel Garcia Reyero Viñas

Marina Ferran Farrés

Yngvar Rossow

MIsabel Borrell Bayona

Andreas Mueller

Enric Odena Garcia

Nuria Jomet

Ruiyi Mao

Wanling Jiang

Xavier Farina

Alejandro Manuel De Peña Hempel

Pablo Vidal ÃLvarez

A pagewide array (PWA) print bar of a printing device prints a calibration pattern on a print medium. The print bar is nominally perpendicular to a media advancement direction in which the print medium advances relative to the PWA print bar during printing. An image of the printed calibration pattern is optically scanned, and a skew angle by which the PWA print bar deviates from true perpendicular to the media advancement direction is calculated based on the optically scanned image. The printing device is calibrated to compensate for the calculated skew angle during subsequent printing.

Calibration to compensate for print bar skew angle

Image data may indicate an average number of drops of printer fluid per pixel. Print data may be generated such that a total number of drops of printing fluid are deposited to a print medium during a pass in a forward direction and a pass in the reverse direction according to a distribution.

Generating a print data for an image

In an example, a processor comprises an ancillary print agent distribution module to determine instructions for a print control module. The print control module may be to control the distribution of print agent onto a first region of a layer of build material in an object fabrication chamber in an additive manufacturing process in which at least one object is generated by selective solidification of each of a plurality of layers of build material and the selective solidification of build material is determined by the distribution of at least one print agent. The instructions determined by the ancillary print agent distribution module may be to cause the print control module to control the distribution of print agent in a second region of a layer of build material in an object fabrication chamber as part of a process which is ancillary to object generation. The first and second regions may be spatially distinct.

Distribution of print agent

A method of printing on a printable medium is disclosed. The method of printing may use a print head having a plurality of nozzles. The printable medium may have a leading edge and a defined zone adjacent to the leading edge. The print head may deposit print agent onto the printable medium via the plurality of nozzles during successive printing passes. The method may comprise printing outside, and not within, the defined zone on the printable medium using a first subset of nozzles of the plurality of nozzles. The method may further comprise printing within, and not outside, the defined zone on the printable medium using a second subset of nozzles of the plurality of nozzles.

Printing within defined zones

A circuitfor controlling a plurality of fluid dispense nozzles(N), the circuitto change an order in which the fluid dispense nozzles(N) are actuated.

Nozzle firing order controller

A printing apparatus comprises a printhead and a controller. The printhead includes dies, each die comprising rows of nozzles, wherein, in an overlapping region, the rows of nozzles of two dies overlap in a first direction, in which a relative movement between the printhead and a print medium takes place during operation of the printing apparatus. The controller is to apply a first weaving mask to a first row of nozzles of a first die and a second weaving mask to a second row of nozzles of the first die, the second weaving mask being different from the first weaving mask, the weaving masks defining, independent of print data, which of the nozzles of the corresponding row are to be used for printing in the overlapping region.

Applying first and second weaving masks

Print apparatus is controlled to execute a print operation comprising a plurality of print sweeps onto a print zone of a print substrate and a corresponding plurality of print advances of the print substrate between successive print sweeps. Print apparatus is controlled to execute an intermediate cutting operation between a pre-cut print sweep and a successive post-cut print sweep of the plurality of print sweeps.

Cutting print substrates

Cells of an n-dimensional object are indexed. A plurality of indexing digits are grouped for each axis of the n dimensions of the n-dimensional object. A first indexing digit of a given group is allocated to each of at least two cells resulting from at least one subdivision of the dimension of the object along the axis of the given group; and an msubsequent indexing digit of the given group is allocated to any subsequent at least two cells resulting from any subsequent at least one subdivision of at least one cell of the at least two cells resulting from the m&#x2212;1subdivision of the dimension of the object along the axis of the given group.

Indexing cells of N-dimensional objects

In some examples, an imaging device may include a controller including processing circuitry to detect, a first quantity of rows of pixels to be included as a first band of a contone image, process the pixels of each row of the first band in parallel raster order, detect a second quantity of rows of pixels to be included as a second band of the contone image; and process the pixels of each row of the second band in response to the completion of the pixels of the first band, where the rows of the second band are processed in parallel in serpentine order with respect to the first band.

Parallel image processes

According to an example, an apparatus may include a processor and a memory. The memory may have stored thereon machine readable instructions that may cause the processor to access an initial halftone image of a three-dimensional (3D) object, the initial halftone image being generated from a continuous tone image of the 3D object. The instructions may also cause the processor to iteratively modify voxel data for the initial halftone image to identify updated voxel data that more accurately corresponds to the continuous tone image than the initial halftone image and to generate halftone image printing data for the 3D object containing the updated voxel data.

3D printed object halftone image generation containing updated voxel data

An example media handling system provides a print media () along a media path () and at least part of the media handling system includes an adhesive material for locating the print media () on the at least part of the media path ().

Media handling system

In an example, a method includes receiving print data indicative of an image to be printed on a substrate. The print data may indicate an image portion in which an image is present and a void portion in which the image is absent. An amount of background print agent to be applied to a region of the substrate corresponding to the locations of the image portion and the void portion on the substrate when the image is printed may be determined. In examples, the amount of background print agent determined to be applied to a region of the substrate corresponding to the location of the void portion on the substrate when the image is printed is greater than the amount of a background print agent to be applied to the region of the substrate corresponding to the location of the image portion on the substrate when the image is printed.

Printing background print agents

A printer for printing on a print medium as said print medium advances through a print zone, the printer including a number of print heads extending over the print zone, each print head including at least one nozzle array wherein at least two adjacent nozzle arrays overlap forming at least one stitching zone in the overlap region; and a printer controller for generating a sequence of nozzle firing commands for each nozzle array to selectively deposit droplets of print fluid on said print medium from said nozzle arrays in accordance with an image to be printed, wherein the printer controller further applies masks having decorrelated patterns to said sequence of firing commands for at least those overlapping nozzles of the nozzle arrays coinciding with the at least one stitching zone to obtain a predetermined optical parameter of the printed image in the stitching zone, irrespective of an offset between two adjacent nozzle arrays.

Printer and computer-implemented process for controlling a printer

In some examples, a printing system includes a printhead comprising a nozzle array including plural columns of nozzles to deliver printing fluid to a print medium, wherein nozzles in a first column of the columns are offset from nozzles in a second column of the columns. A controller is to control printing onto the print medium using the printhead by, for each respective pass of a plurality of passes of the printhead over the print medium, controlling an advance of the print medium for a print mask pattern that controls firing of the nozzles of the printhead, where the controlled advance of the print medium causes nozzles from different columns of nozzles of the nozzle array to deliver dots of printing fluid to a given row of a swath in successive passes of the plurality of passes.

Controlling advance of print media to deliver printing fluid from plural columns of nozzles

Example implementations relate to swath height error compensation. Some examples may determine a density of an image to be printed in an overlap area of a printing material. The overlap area may include target pixels capable of being printed by a first set of drop ejection elements and a second set of drop ejection elements that are redundant to the first set of drop ejection elements. Some implementations may also determine a mask to apply to the first and second set of drop ejection elements based on the determined density, and the mask may designate at least one additional drop to apply to at least one target pixel in the overlap area by at least one of the first and second set of drop ejection elements. Some implementations may also apply the mask to the first set of drop ejection elements and the second set of drop ejection elements.

Compensating swath height error

Growing community of inventors

Sant Quirze del Valles, Spain

Utpal Kumar Sarkar