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:
May. 24, 1994
Filed:
Jan. 04, 1993
Izadpour Khormaee, West Linn, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A method and apparatus for detecting ink flow through the printhead of an inkjet pen includes sensing the temperature of the printhead substrate as the inkjet pen prints a test pattern into the printer spittoon. The method includes printing a test pattern and storing data representing the temperature of the printhead. The method includes summing the change in temperature of the printhead between an initial point and points at intervals during the printing of a test pattern to provide a thermal history of the printhead. Ink flow is determined from the rate of temperature change during the printing of a test pattern, and from the change in thermal history of the printhead among test patterns.