Hewlett-Packard Development Company, L.p.

Purdue Research Foundation

Joan Vidal Fortia

Lluis Abello Rosello

Jorge Martinez De Salinas Vazquez

Peter Morovic

Jan Morovic

Javier Maestro Garcia

Ron Burns

Fernando Viciano Martin

Ivan Perez Laka

Robert Alan Ulichney

Jan Philip Allebach

Sergio Puigardeu Aramendia

Gideon Amir

Jordi Arnabat Benedicto

Utpal Kumar Sarkar

Marti Rius Rossell

Noam Shaham

Ram Dagan

Jose Galmes

Frank Perdicaro

Ronald J Burns

Yafei Mao

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

In an example, a method includes acquiring data representing an article to be printed, the data comprising an element set associated with a print addressable location, the element set comprising a first element subset and a second element subset, wherein the first element subset and the second element subset comprise an element identifying a print material selection which is associated with a probability that the print material selection is to be applied to the associated print addressable location. The method further includes determining a first set of cumulative probability values associated with the elements of the first element subset and determining a second set of cumulative probability values associated with the elements of the second element subset. The first set of cumulative probability values may span a first predetermined value range and the second set of cumulative probability values may span a second predetermined value range.

Determining cumulative probability values for subsets of elements

In an example, an image processing system may include an identification engine, a map engine, and a control engine. In that example, the identification engine may identify a color mapping resource in response to a classification identifier corresponding to image data, the map engine may map the image data with the color mapping resource having color space clause corresponding to the classification identifier, and the control engine may generate control data for operating a print apparatus to print based on the color mapping resource.

Color space values corresponding to classification identifiers

A method of recirculating fluid in a printhead die is provided. The method comprises generating ejection data specifying a nozzle of the printhead from which a drop is to be ejected and storing the ejection data in a first memory. Recirculation data is generated for the nozzle for which a recirculation operation is to be performed, and the recirculation data is stored in a second memory different from the first memory. Fluid is recirculated in the nozzle on the basis of the recirculation data in advance of ejecting a drop from the nozzle on the basis of the ejection data. The recirculation data is generated based on the respective ejection data for the nozzle.

Recirculating fluid in a printhead

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

An example system includes a controller. The controller is to determine a first end point of a previous frame in a first image. The first image is to be printed on a first ribbon. The controller is to determine a second end point of the previous frame in a second image to be printed on a second ribbon. The controller is to create a current frame containing first image data from the first image starting after the first end point, second image data from the second image starting after the second end point, and third image data from a beginning of the first image. The system includes an image engine to form an image corresponding to the current frame on a medium.

Print frames creation

Examples relate to providing synchronized look-up table loading. In some examples, a print job is processed using an initial look-up table in processor memory. In response to the processing of the print job reaching a buffer trigger row of a portion of the print job, look-up metadata is accessed to locate a next look-up table. At this stage, the next look-up table is dynamically loaded into the processor memory as the processor continues to process the print job, where the processing of the print job begins using the next look-up table after a target row of the portion of the print job is reached.

Synchronized look-up table loading

The present disclosure relates to a printhead control system for a printer, wherein the printer includes at least one printhead comprising a plurality of nozzles for ejecting printing fluid, wherein the nozzles include high drop weight nozzles and low drop weight nozzles ejecting drops of different drop weight, and are each arranged to eject printing fluid on a print medium such as to print images in frame areas of the print medium and such as to clean nozzles in spit bar areas of the print medium; the printer further includes a transport unit for moving the print medium relative to the printhead, wherein the print medium includes frame areas for printing images and spit bar areas for cleaning the nozzles; the printhead control device including: a module to determine a first group of said nozzles located over a frame area of the print medium and a second group of said nozzles located over a spit bar area of the print medium; a module to operate the high drop weight nozzles of the first group such as to eject printing fluid and print an image in the frame area; a module to operate disable the low drop weight nozzles of the first group such as to not eject printing fluid in the frame area; and a module to operate the high drop weight nozzles and the low drop weight nozzles of the second group such as to alternately eject printing fluid in the spit bar area.

Printhead control system and inkjet printer system

Examples relate to providing synchronized look-up table loading. In some examples, a print job is processed using an initial look-up table in processor memory, in response to the processing of the print job reaching a buffer trigger row of a portion of the print job, look-up metadata is accessed to locate a next look-up table. At this stage, the next look-up table is dynamically loaded into the processor memory as the processor continues to process the print job, where the processing of the print job begins using the next look-up table after a target row of the portion of the print job is reached.

A color input image comprising a plurality of pixels, each pixels encoded in RGB color space, is processed to convert the RGB pixels to another color space domain for printing the color input image. The number of colors within a cell of the input image is reduced. Each cell comprises an N&#xd7;M array of pixels and the number of colors is reduced to a maximum of b source colors, wherein b is a positive integer equal to or greater than 2. Each of the resulting colors of each cell is calibrated to generate a printable color. The cells are then processed to convert the pixels of each cell into another color space, for example, to determine ink vectors, in another color space, for each calibrated color.

Image processing that includes reducing a number of colors within a cell of an image

A method to selectively compress an image in a printing process comprises the steps of providing a first representation of an image to be printed on a printer to a printing pipeline, processing the first representation in the printing pipeline to derive a second representation of the image, wherein the second representation comprises physical printing parameters adapted to the image and the printer, and compressing the second representation to obtain a compressed third representation of the image. The third representation of the image is again supplied to the printing pipeline, and is processed in the printing pipeline to derive a fourth representation of the image. The fourth representation of the image is provided to a printhead of the printer for printing. The invention also relates to a corresponding system to selectively compress an image in a printing process, as well as to a computer-readable medium comprising computer-readable instructions to cause a computer coupled to or integrated into a system to selectively compress an image in the printing process to perform a method with the steps described above.

Methods and systems to compress an image in a printing process

A method and apparatus for printing is disclosed. The printing is done with multiple printhead dies. The nozzles in the different printhead dies are fired using different phases in an up-sampled encoder signal. The different phases correspond to a print offset between the different printhead dies.

Printing with multiple printhead dies

A method to code print data where print data to control a print head of a printer is received, where a coding strategy to change the size of the print data is determined based on at least one characteristic of a print mode of the printer, and the size of the print data is changed using the determined coding strategy.

Apparatus and methods to code print data

An image may be printed at variable speed. An image density profile provides an estimation of power to be consumed while printing the image. A power consumption profile is generated based on the image density profile and by taking into account distance offsets between nozzles that are used to print the image. The image may be printed at different speeds based on the power consumption profile.

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Barcelona, Spain

Joan Vidal Fortia