The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 25, 2000
Filed:
Mar. 01, 1999
David C Barton, Vancouver, WA (US);
William J Allen, Portland, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
In color graphics printing, incompatible inks, such as true black and color inks, tend to bleed across color field boundaries. Moreover, in four-color systems, there is a discontinuity in the physical color gamut, as distinguished from the logical color gamut, associated with the redundant color. A method is disclosed for alleviating both problems by adjusting image data prior to dithering. The method slightly shifts the logical color indicated in the image data so as to avoid the discontinuity that arises with neutral colors. Preferably, in a four-color printing system, yellow is depleted in the image data, so that after dithering, more dots of blue ink are printed in a given area than would be printed otherwise. For each pixel, the amount of correction is inversely related to the color saturation. The presence of blue ink dots within the substantially black field reduces bleed along the field edges.