Hewlett-packard Development Company, L.p.

Carles Flotats

Jose M Rio Doval

Rodrigo Ruiz

David Claramunt

Francesc Subirada

Marcos Casaldaliga

Marc Jansa

Raimon Castells De Monet

Fernando Juan

Antonio Monclus

David Toussaint

Francisco Guerrero

Gonzalo Gaston

Xavier Soler

Ezequiel Jordi Rufes

Raimon Castells

Marti Rius

Jordi Ferran Cases

Francisco Javier Rodriguez

Joaquim Veciana

Jonas Ingemar Åström

Abel Martinez

Isabel Borrell

Laura Sanchez

Fancesc Subirada

Jose M Rio

Calibrating a media drive, comprising advancing media with a media drive while detecting media advances within the printer, determining an error in the media advances, and calibrating the media drive so as to at least partly compensate for the determined error.

Media advance

In one embodiment, printing, on a first side of a media, of a first plurality of plots and a plurality of associated fiducials is caused. For each of a second plurality of plots, using data from a sensor, a distance to one of the plurality of associated fiducials is measured to discern a reference for printing that plot on a second side of the media. Printing of the second plurality of plots on the second side is caused so that each of the second plurality of plots is substantially in registration with one of the first plurality of plots.

Method and system for two sided printing

A system for adjusting measurements is disclosed. In one embodiment, the system includes an optical sensor having a window marked with two fiducials and at least one processor coupled to the optical sensor.

Adjusting measurements

A method for automatic pen alignment in a printing apparatus, wherein the printing apparatus has a scan direction or x-axis and a media advance direction or y-axis, orthogonal to said scan direction or x-axis, the method comprising the steps of performing a pen alignment process, determining an alignment correction algorithm to be applied during subsequent printing, to compensate for the misalignment determined in said pen alignment process, measuring an output angle of the media, defined as the angle between the y-axis and the actual direction of advance of the media, with at least one optical sensor arranged stationary on the printing apparatus, and employing the measured output angle to modify the alignment correction algorithm to be applied during subsequent printing.

Method for automatic pen alignment in a printing apparatus

Illumination utilizing a plurality of light sources is disclosed. In one embodiment, an illumination level is set to result in a desired contrast level. Calculations are made to derive electrical current values for each of the plurality of light sources which will illuminate a plurality of selected locations at the set illumination level.

Illumination utilizing a plurality of light sources

A printer device comprising a mechanism adapted to generate an image on an image surface, the device comprising a sensor adapted to image a predetermined optical object located substantially on the image surface, the device being adapted to determine at least one dimension of the object's image and thereby determine the distance separating the mechanism and the image surface.

Media-position sensor system

A multicolor-printer has at least a first and a second print station, first and second optical sensors and a surface recordings comparator. The first and second print stations are arranged to print images on a surface of a moving recording medium. The first and second optical sensors view, at the first and second print stations, an area of the recording medium surface to obtain at least one first surface recording, in a manner related to the first print station's image printing, and second surface recordings, respectively. A storage is arranged to store the first surface recording. The surface recordings comparator is arranged to test, during the recording medium movement, for correspondence of second surface recordings with the stored first surface recording. The printer is arranged to repeatedly, within one image, register raster lines of the image of the second print station to corresponding raster lines of the image of the first print station in response to correspondences found between the first and second surface recordings.

Multicolor-printer and method of printing images

A method for image recognition. In the method, a section of an element is imaged while the element is at a first speed to obtain a first image pattern. The section of the element is also imaged while the element is at a second speed to obtain a second image pattern. The first speed differs from the second speed. In addition, the apparent speeds of the element in the first image pattern and the second image pattern are made to appear approximately the same.

Making the apparent speed of elements imaged at different speeds approximately the same for image recognition

A media-positioning sensor assembly in one embodiment of the invention is disclosed that includes a mechanism and a media-positioning sensor. The mechanism moves back and forth over media along a first axis. The media advances past the mechanism along a second axis perpendicular to the first axis. The media-positioning sensor is situated on the mechanism and is to detect positioning of the media relative to the mechanism along at least one of the first axis and the second axis.

Dual-axis media-positioning sensor

A method and apparatus is used to detect and compensate for printhead rotation in an inkjet printer. The detecting operation includes receiving an initial image of a pattern taken from a medium as the printhead passes over the medium, receiving a subsequent image of the pattern taken from the medium as the printhead continues to pass over the medium, comparing the initial image of the pattern and the subsequent image of the pattern taken from the medium and identifying a rotation of the printhead in the inkjet printer passing over the medium if the comparison indicates the initial image of the pattern is rotated relative to the subsequent image of the pattern. The compensation operation includes modifying the timing settings associated with the firing of the nozzles in the inkjet printhead to compensate for the rotation of the printhead.

Method and system for printhead rotation detection using photosensors

A sensor system for detecting skew in print media along the feed path of a hardcopy device is disclosed. In one embodiment of the invention the system is arranged to generate a first image of a portion of print media at a first position along the feed path and to generate a second image of the portion of print media at a second position along the feed path, the system is arranged to compare the first and second images and thereby detect a change in the angle of skew of the media between the first and second positions.

Media-position media sensor

The printheads of an inkjet printer have a service station movable in a direction transversely of a printhead scanning direction and comprising servicing modules for undertaking different functions, one of the modules being detachable from the rest. The detachable connection comprises a rotating hook and a fixed hook which automatically interengage and disengage.

Printhead service station

A sensor system for detecting skew in print media along the feed path of a hardcopy device is disclosed. In one embodiment of the invention the system is arranged to generate a first image of a area of print media at a first position along the feed path and to generate a second image of the area of print media at a second position along the feed path, the system is arranged to compare the first and second images and thereby detect a change in the angle of skew of the media between the first and second positions.

An embodiment of the invention is disclosed in which media advances at a first speed to an interim position based on signals from a first sensor having a first accuracy. While the media is advancing at the first speed, signals are accumulated from a second sensor having a second accuracy greater than the first accuracy. Upon the media reaching the interim position, an actual position of the media is adjusted based on the signals accumulated from the second sensor.

Media positioning with differently accurate sensors

A method of an embodiment of the invention is disclosed in which a linear imaging array captures a first one pixel-wide image of media, and the media is effectively advanced relative to the linear imaging array. The linear imaging array captures a second one pixel-wide image of the media, and the first and the second one pixel-wide images are compared to determine relative advancement of the media.

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Barcelona, Spain

Carles Flotats