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:
Aug. 27, 2002
Filed:
Nov. 23, 1999
Kirkpatrick William Norton, San Diego, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A method and apparatus for controlling firing energy in an inkjet printer are embodied in a control circuit and a regulated pen voltage source for an inkjet printer pen. The control circuit includes switches connected between the nozzle resistors of the pen and a low voltage rail. The control circuit is configured to control the voltages across the switches within a known tolerance, independent of variations in the switch current, integrated circuit process variations, temperature variations, and variations in the resistances of the nozzle resistors. The voltage provided to each nozzle resistor by the pen voltage source is adjusted to compensate for changes in the voltages across the switches.