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. 10, 1990
Filed:
Apr. 25, 1989
Robert D Haselby, San Diego, CA (US);
Jeffrey S Best, San Diego, CA (US);
Samuel A Stodder, Encinitas, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A media advance system for swath-type printers for precisely positioning the media for successive swath printing. A dual photodiode line sensor is mounted on the print head. The diode active areas are separated by less than the line widths of lines printed in the media margin. Circuitry is provided to provide a signal indicative of the difference between the photocurrents produced by each photodiode. For the first swath of the page or plot, marginal lines are drawn by the first and Nth print device of the print head. Without moving the media, the line sensor is positioned over the marginal line printed by the first device, and the resulting difference signal is saved as a reference value. The media is then advanced until the same value of the difference signal is obtained from the line image of the marginal line drawn by the Nth print device. The media is then advanced a predetermined amount to precisely position the media for the next successive swath to be printed.