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:
Sep. 15, 1998
Filed:
May. 26, 1995
Donald E Wenzel, Albany, OR (US);
David E Hackleman, Monmouth, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A ferromagnetic ink is formed by a dispersion of ferromagnetic particles mixed with an ink base. Drops of the ink are ejected from an inkjet printhead to print characters or markings onto a print media sheet. To resist clogging printhead nozzles, the dispersed ferromagnetic particles have an average diameter equal to or less than approximately 1/10 of the average nozzle diameter. A magnetic field is applied to the ejected ink drops during printing to direct, or more specifically bias, the ink drops toward the print media. The magnetic 'biasing' force aids in maintaining drop shape along the ejection path, and in reducing bounce. As a result, edge roughness and spray are decreased so as to improve print quality. In alternative embodiments, the magnetic field source is formed by a permanent magnet or electromagnet. Such a field source is integral to or adjacent to a printer platen. The field source is located adjacent to the printhead and in several embodiments extends along the scan path of the printhead. In one embodiment the field source is formed on the ink cartridge.