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:
Jun. 12, 2001
Filed:
Mar. 22, 1999
Paul David Gast, Vancouver, WA (US);
Keshava A Prasad, San Marcos, CA (US);
Brooke E Smith, Brush Prairie, WA (US);
Michel A. Riou, Milwaukie, OR (US);
Steven D Looman, Corvallis, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A black printhead is installed in a scanning carriage with at least one primary color printhead on both sides of the black printhead. To reduce the drying time of a printed black ink pattern and to achieve other benefits, a first one of the primary color inks underprints the black ink in a first scan direction, and a second one of the primary color inks underprints the black ink in an opposite second scan direction. To minimize hue shifts due to the different underprinted colors, the black ink is overprinted, during the same scan that printed the underprinted ink and black ink, by a color ink that is different from the underprinted ink, so that the resulting black image printed in both scan directions will contain the same three color components. In one embodiment, the order of print cartridges in the scanning carriage, as viewed from the front of the printer, is cyan, black, magenta, and yellow. Other orders may also be used, and additional colors may be used. The invention is also applicable to a color printer using a single printhead with multiple sets of nozzles, each set printing a different color ink.