Hewlett-packard Development Company, L.p.

Hewlett-packard Company

Jose Luis Valero

Ramon Vega

Oscar Martinez

Michael W Cumbie

Mark H MacKenzie

Garrett E Clark

Xavier Bruch

Francesc Subirada

Gianni Cessel

Martin Urrutia

Gonzalo Gaston

Corrina Hall

Jeffrey A Wagner

A temperature of one printing element is adjusted based upon a temperature of another of printing element.

Printing element temperature adjustment

In a method of printing a plurality of pages during a print job, a page-wide-array printing device having redundant dot-forming elements is used. Print masks distribute dot-forming-element activity between the redundant dot-forming elements in a manner taking into account known malfunctions of dot-forming elements to hide such malfunctions, or reduce a visible effect of such malfunctions in the pages printed. The method includes generating a plurality of print masks which are different, as they distribute the dot-forming-element activity in different ways, but are equivalent, since they are based on the same knowledge of dot-forming-element malfunctions; dividing the print job into page-sets of at least one page; and printing the different page-sets of the print job using different equivalent print masks, thereby distributing the dot-forming-element activity in different ways from page-set to page-set.

Error reduction by print masks

Fixer is detected on a print mediaby applying a predetermined pattern, FIG., of fixer to the media, and over or under-printing it with a fill of coloured ink, and then optically detecting the predetermined pattern. For example, magenta ink may be applied over the fixer pattern on a glossy media, areas with both fixer and ink having a detectable increase in optical density compared to areas with ink alone. The pattern is scanned and the image information is used to check fixer nozzle functionality and fixer printhead alignment.

Detecting fixer in hardcopy apparatus

An incremental printer comprising a plurality of printing elements arranged to print different portions of an image, the printer being arranged, prior to printing an image, to identify elements that are not required for printing the image and to implement an element servicing routine, the printer being arranged to exclude one or more of the identified elements from the servicing routine.

Method and apparatus for operating a printer

To check that nozzles of printheadsapplying fixer or an ink to a print mediaare operating correctly, the fixer or ink is applied to selected locations on a fluorescent print media which is then subjected to ultra-violet radiation; the reflectivities at these locations are detected in the visible spectrum and the information is analyzed using appropriate image processing algorithms. In an ink-jet printer, for example, applied fixer may be irradiated with ultra-violet light by a sourceand applied inks may be irradiated with visible light, with a common detector in the visible light range being employed.

Fixer or ink detection in hardcopy apparatus

A printer apparatus comprising one or more printing elements arranged to print on print media located in a print position, the apparatus further comprising first and second media paths respectively adapted to feed media to and away from the print position, the apparatus being arranged to selectively divert a print media sheet from the second media path to the print position, the apparatus being arranged to implement a servicing routine comprising marking the diverted sheet with one or more of the printing elements.

Printer device and method

A printer apparatus comprising one or more printing elements arranged to print on print media in a print zone and a transport path arranged to transport printed sheets from the print zone to an output position, the apparatus further comprising a scanner arranged to scan a printed sheet, and diverting means arranged to selectively divert a printed sheet to the scanner, the scanner being located such that the apparatus may continue to print and transport sheets to the output position during the scanning process.

The present invention is directed to a method and apparatus for testing the operational status of printhead nozzles. High throughput drop detection devices are used to detected ink drops that are fired from the printhead nozzles, and the operational status is determined from the ink drop characteristics. The ink drop characteristics may include the presence or absence of an ink drop. Ink drop characteristics may also include the size and the location of an ink drop. The drop detection devices are capable of detecting a plurality of ink drops that are ejected substantially simultaneously.

High throughput parallel drop detection scheme

The presence of invisible ink drops may be relatively easily detected on a print medium by detecting the changes in specular reflection between the print medium and the print medium upon which invisible ink drops are located. An optical sensor having a detector for capturing diffuse reflections and a detector for capturing specular reflections may be implemented to detect the presence of both sufficiently colored ink drops as well as invisible ink drops. In one respect, the location of the detected invisible inks may be utilized to determine whether an ink ejection element that fired the drops of invisible inks is offset or misaligned. In another respect, the drop size of the ink drops may be detected to determine the health of the nozzles. In this regard, the method of detecting the presence of invisible ink drops may be implemented as a routine or sub-routine to determine ink ejection element alignment, apply a positional calibration of the ink ejection element, and apply a printing mask.

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Barcelona, Spain

Jose Luis Valero