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. 26, 2001
Filed:
Mar. 04, 1997
Josep Maria Serra, Barcelona, ES;
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
Bidirectional scanning printheads discharge color-ink drops at ultrahigh resolution while scanning in each direction, to form color swaths on a print medium. The heads are at least partially aligned with respect to the longitudinal axis of the medium, so that the swaths at least partly overlap in that direction. An advance mechanism intermittently steps the print medium longitudinally, to enable displacement of successive swaths. A control system alternates (1) one full reciprocation of the heads, to discharge drops while scanning each way across the medium, with (2) each step of the advance mechanism. Preferably the heads print, while scanning each way, a respective generally fixed nonzero fraction of the total amount of each secondary color to be printed. In this way the overall appearance of each secondary is essentially consistent and partway between two appearances respectively produced by scanning two ways. This invention avoids the long-printzone drawbacks associated with full-height-staggered heads. Preferably the fractions for all the swaths are about equal, so that the consistent appearance for each secondary is essentially the average of two appearances respectively produced by scanning two ways. Various printmasks complete each swath in eight passes with four print-medium advances, or four passes and two advances, or two and one—in each case printing in every pass.