Hewlett-packard Development Company, L.p.

Hsue-Yang Liu

Matthew Allen Shepherd

Weiyun Sun

Mark H MacKenzie

Tod S Heiles

Michael Brookmire

Elizabeth Ezetta

David E De Bellis

Teresa Gene Trueba Embree

Jay Stephen Gondek

Jason M Quintana

Bradley D Chung

Luke P Sosnowski

Brooke E Smith

Anthony Peter Carcia

Miguel Angel Lopez Alvarez

Edward L Feldhousen

Thieu X Dang

Jan Elizabeth Casey

R Joseph Megaw

Mark H Mackenzie

Color values are measured for a set of color targets printed by a reference printing device on a medium of a reference media type. A different printing device prints a subset of the set of color targets on another medium of this reference media type. The color values of the subset of color targets printed by the different printing device are measured, and the different device calibrated based on the measured color values for both the set that the reference printing device printed and the subset that the different device printed. The different printing device can then also be calibrated for a different media type, based on a transformation of the set of color targets printed by the reference printing device on a medium of the different media type relative to the set of color targets printed by the reference device on the medium of the reference media type.

Printing system calibration using reference printing device

According to examples, an apparatus may include a processor and a memory on which is stored machine readable instructions that are to cause the processor to determine a size of a chip gap between a first sensor chip and a second sensor chip, access a model that estimates an amount of positional shift of a target centroid, and apply the determined chip gap size and the accessed model on an image captured using the first sensor chip and the second sensor chip to compensate for an estimated positional shift in a centroid of a calibration target in the captured image by causing a location of the calibration target centroid in the captured image to more accurately correspond to an actual location of the calibration target centroid on an object from which the captured image was captured.

Calibration target shift compensation

A method including printing a calibration pattern with a wide array printhead having a plurality of printhead dies. The method includes scanning the calibration pattern with a scanbar having a width less than a width of the wide array printhead by indexing the scanbar to a plurality of selected positions across a width of the calibration pattern and providing a scanned calibration image at each selected position, the calibration images together providing a scan of the full width of the calibration pattern, and measuring alignment between successive printhead dies based on the calibration images.

Die alignment with indexing scanbar

A skew sensor calibration unit including a scanner providing a scanned image of a sheet as the sheet is conveyed along a transport path, the scanned image including a leading edge of the sheet and a skew detection pattern printed thereon by a printhead. A calibration module measures a top skew of the sheet based on position signals from a plurality of skew sensors indicating a position of a leading edge of a sheet as the sheet is conveyed along the transport path, measure an image skew of the sheet relative to the printhead based on the scanned image, and generates a calibration factor that when applied to the measured top skew provides a calibrated top skew that matches the image skew.

Skew sensor calibration

A printer is disclosed. The printer has a print engine that mounts a first printhead and a second printhead adjacent to the first printhead in a staggered line of overlapping printheads. Each printhead has at least one row of nozzles. The blending nozzles in the first printhead overlap with blending nozzles in the second printhead. When printing, the non-overlapping nozzles in the first printhead use a default ink modulation amount and the blending nozzles in both printheads use a scaled ink modulation amount.

Ink modulation for nozzles

A printer includes a printbar having plural dice partially overlap in the direction of rows and a halftoner. The dice receive nozzle firing data which determines when and where the individual print nozzles are to be operated in order to emit the colorant onto the media so as to form the desired printed image on a media. The halftoner is a bidirectional error diffusion halftoner that is structured to generate halftoned data. The halftoned data is mappable into the firing data. The halftoner includes a serpentine direction reverser which is structured to halftone print data image pixels in a first serpentine direction to form halftoned data and then to halftone print data image pixels in an opposite serpentine direction to form the halftoned data.

Serpentine direction reversal in bidirectional error diffusion halftoning

A sweep speed is determined for sweeping a printer head of a printer across a print medium for printing a swath of an image on the print medium. A distance by which to advance the print medium is at least partially determined in accordance with the determined sweep speed and the print medium is advanced by the determined distance.

Print medium advancing distance adjustment

A method for calibrating one or more printheads includes printing a reference image using a first portion of image forming points of a first printhead, printing a diagnostic image using a second portion of image forming points of either the first printhead or a second printhead, detecting an optical density of the combined reference image and the diagnostic image and determining a compensation value based upon the optical density.

Printhead error compensation

A method of registering an image onto a sheet of media on an imaging surface of a printer having a printhead for imaging onto the sheet, comprising: detecting a position of said sheet of media being advanced onto the imaging surface using a first sensor positioned along said media path upstream of the printhead; and firing the printhead at a time based on the detected position and a calibrated distance between the sensor and the printhead.

Method and apparatus for image registration

A multi-carriage printing device has a first member, a first bar mounted on the first member, and a first printer carriage mounted on the first bar. The device further has a second bar mounted on the first member, a second printer carriage mounted on the second bar, and a first temperature sensor positioned to sense a first temperature of the member.

Multi-carriage printing device and method

Exemplary embodiments of the invention include systems and methods of reducing visible print defects in drum printers having multi-die printheads oriented substantially perpendicular to the print media path. The exemplary embodiments include printing very small amounts of additional ink via empirically determined printing masks in addition to the normal image content, such that the print defects become less visible. Further exemplary embodiments include printing the additional ink during times typically utilized for print drying.

System and method to hide die-to-die boundary banding defects in a drum printer

A method for locating a cutter in a web fed photo imaging system including the steps of measuring an actual fiducial distance between consecutive fiducials, comparing a measured actual fiducial distance between consecutive fiducials to an imaging engine feed distance, calculating a feed distance scaling factor equal to a difference between an average actual fiducial distance and the imaging engine feed distance divided by a total number of discrete incremental moves between fiducials and adjusting the imaging engine feed distance in an amount equal to the scaling factor.

Growing community of inventors

Vancouver, WA, United States of America

Hsue-Yang Liu