Hewlett-packard Development Company, L.P.

David Gaston

Ramon Vega

Francesc Subirada

Angel Martinez

Sergio Puigardeu

Alex Andrea

Jordi Sender

Marti Rius

Silvia Miramanda

Xavier Soler

Joan Jorba

Marc Serra

Oscar Ciordia

Joan Joroa

Josep Antoni Rodenas

A method of printing an image on a substrate using a page-wide-array printer and a page wide array printer is provided. The method includes printing a first portion of the image as relative movement occurs between the substrate and the print heads, and printing a second portion of the image as relative movement occurs between the substrate and the print heads, such that there exists an area of overlap between the first portion of the image and the second portion of the image. The substrate may be moved in a first direction relative to the print heads whilst the first portion of the image is printed, moved in a second direction opposite to the first direction; and moved in the first direction again whilst the second portion of the image is printed. The substrate may be printed whilst the substrate is moved in the second direction.

Method and printer for multi-pass page-wide array printing

Printing is performed at a full resolution using a first set of nozzles and a second set of nozzles arranged on a printhead. Printing is performed at less than the full resolution using the first set of nozzles less any nozzles in the first set of nozzles that have been determined to be defective. The second set of nozzles is not used for printing at less than the full resolution except for a subset of nozzles in the second set of nozzles that are used to replace nozzles from the first set of nozzles that have been determined to be defective.

Defective nozzle replacement in a printer

A method of printing on a substrate and a printer are provided. The method uses a printer comprising a print head and a mask having a hole therethrough, the mask being disposed between the print head and the substrate, and comprises aligning the hole with the print head; printing on the substrate through the hole; and misaligning the hole with the print head so that the print head is covered by the mask. The method may allow the servicing of a print head in the array while the printer is printing on the substrate using at least one of the remainder of the print heads in the array.

Printers and printhead cleaning primarily in page-wide array printers

A printer is configured to manage a signal-to-noise ratio of a signal produced by a sensor scanning a print test pattern. The print test pattern is printed while controlling ink density printed by each of one or more pens. Each ink density is selected so that the signal-to-noise ratio exceeds a threshold as the print test pattern is scanned. Pens within the printer are aligned or otherwise maintained by adjusting nozzle firings as indicated by data obtained from the signal during the scanning.

Ink density impact on sensor signal-to-noise ratio

Techniques for calibrating a scanner mounted on a scanning carriage of an image forming device. In one embodiment, a method of calibrating an optical sensor of a color image forming device includes positioning a prefabricated optical sensor target at the service area of the image forming device, the target including a plurality of target patches of predetermined different colors, moving the carriage to the service area, acquiring one or more images of the plurality of target patches, and using the one or more images to perform a plurality of calibrations of the optical sensor. In another embodiment, a method of measuring a reference position of a carriage mounted sensor array for an image forming device includes moving the carriage to a service area, generating a light beam from a carriage-mounted light source at a position adjacent an end of a sensor array, the light beam at an acute angle relative to an array axis, reflecting the beam from a reference target mounted in the service area at a known position, acquiring an image of the reflected beam by the sensor array, and using the location of a high intensity area of the image to determine the reference position of the optical sensor.

Calibration and measurement techniques for printers

By implementation of an optical scanner, the calibration of printheads of a printing mechanism may be performed in a relatively short period of time as compared to known techniques. In one respect, the time required to perform the calibration may be substantially reduced by virtue of the relatively wide field of view of the optical scanner. The relatively wide field of view generally enables for the scanning of test patterns to be performed with a relatively fewer number of scanning passes, thus reducing the time required to perform the scanning operations as well as the calibration operations. In addition, the scanning operations may yield relatively more accurate results as compared to known scanning operations. In one respect, optical scanners are capable of detecting smaller drops of ink on print media by virtue of their higher resolution capabilities. In another respect, all of the printed colors may be accurately detected through implementation of a red, green, blue (RGB) charge coupled device (CCD) contained in the optical scanners.

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Barcelona, Spain

David Gaston