Hewlett-packard Company

Pitney Bowes Inc.

Hewlett-packard Development Company, L.p.

Shailendra Kumar

William Berson

Gonzalo Gaston

Javier Lagares

Winthrop D Childers

Brian J Keefe

Steven L Webb

Josep Maria Serra

Frank Drogo

Hanno Ix

Kai Kong Iu

Joan Manuel Garcia

Juan Carles Vives

Barbara Parcells

A program creates a unitary mask for use over a whole image, with one pattern. The mask need not be full image size; it may be tiled. In the field a printer forms a mask and prints with it, best in the same session, before another image needing another mask, whether due to different image activity or type, or operating conditions. Constraints are controlled to ensure solution. Printout can start before a mask (even the part needed to finish a top swath) is done, going columnwise in each swath. In other invention facets, a program forms a mask of size significant relative to the program and prints with it. Other facets check print conditions and form adapted masks; or find nozzles that cannot back up a known-failed nozzle and to back it up form masks with all able nozzles; or assess image activity and inject mask randomness accordingly.

Masks on demand for use in incremental printing

Described is a dynamic multi-pass print mode correction method which corrects for malfunctioning or inoperable ink ejection elements by substituting a fully functioning ink ejection element. The method comprises the steps of obtaining a printmask; identifying ink ejection elements which are malfunctioning; ascertaining potential replacement ink ejection elements from the printmask for the ejection elements which are malfunctioning; selecting replacement ink ejection elements from the potential replacement ink ejection elements; and modifying the printmask by removing the malfunctioning ink ejection elements from the printmask and replacing them with the selected replacement ink ejection elements.

Dynamic multi-pass print mode corrections to compensate for malfunctioning inkjet nozzles

Full-color swaths produced in opposite scanning directions are offset to conceal or eliminate the color-cast effects of the varying deposition order which is inherent in bidirectional operation with in-line pens. Offsets are produced by unequal printing-medium advance between oppositely directed sweeps, or by alternating forward and reverse advance steps between oppositedly directed sweeps, or by both unequal and alternate-reverse steps; or by pen masking. Color-cast effects of varying drying/wicking time, too, are minimized.

Maximum-diagonal print mask and multipass printing modes, for high

In a inkjet print cartridge ink flows from the reservoir around the edge of the silicon substrate before being ejected out of the nozzles. During operation, warm thermal boundary layers of ink form adjacent the substrate and dissolved gases in the thermal boundary layer of the ink form the bubbles. If the bubbles to grow larger than the diameter of subsequent ink passageways these bubbles choke the flow of ink to the vaporization chambers. This results in causing some of the nozzles of the printhead to become temporarily inoperable. The disclosure describes a method of avoiding such a malfunction in a liquid inkjet printing system by providing a method for reducing residual air bubbles in an inkjet print cartridge by flushing the empty cartridge by passing carbon dioxide through the fill port or the ink ejection nozzles prior to filling the print cartridge with ink and thereby eliminating residual air bubbles from the print cartridge when the print cartridge is filled with ink.

Gas flush to eliminate residual bubbles

An identification card and method and apparatus for producing and authenticating such an identification card. A person whom the identification card will identify, is scanned to produce a digital signal which is compressed, encrypted, and coded as a two dimensional barcode or as some other appropriate form of coding, which is incorporated into one portion of the identification card. The image is also printed or otherwise embodied onto another portion of the identification card. A text message maybe appended to the signal before it is encrypted and also printed as plain text on the identification card. In one embodiment the signal representing the image is encrypted using a public key encryption system and the key is downloaded from a center. To validate the card the coded message is scanned, decoded, decrypted, expanded and displayed. The card may then be authenticated by comparison of the displayed representation of the image and the displayed text message with the image and text message with the image and text message printed on the card. A secure record of the verification transaction is made. In one embodiment the record is electronically notarized.

Method for verifying an identification card and recording verification

An identification card and method and apparatus for producing and authenticating such an identification card. An object or other entity for which the identification card will evidence identity, status or characteristics is scanned to produce a digital signal a portion of which is compressed, encrypted, and coded and which is recorded on a magnetic strip on the identification card. The image is also printed or otherwise embodied onto another portion of the identification card. A text message maybe appended to the signal before it is encrypted and also printed as plain text on the identification card. In one embodiment the signal representing the image is encrypted using a public key encryption system and the key is downloaded from a center. This key maybe changed from time to tome to increase security. To facilitate authentication the corresponding decryption key is encrypted with another key and incorporated on the card. To validate the card the coded message is scanned, decoded, decrypted, expanded and displayed. The card may then be authenticated by comparison of the displayed representation stroboscopically superimposed on the image and the displayed text message with the image and text message printed on the card.

Growing community of inventors

San Diego, CA, United States of America

Shailendra Kumar