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:
Mar. 06, 2001
Filed:
Dec. 22, 1997
Marilyn Louise Zuber, Shedd, OR (US);
Donald L. Michael, Monmouth, OR (US);
Susan A. Chavez, Corvallis, OR (US);
Nancy Leigh Herald, Corvallis, OR (US);
Brian L. Helterline, Salem, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A method and apparatus for detecting the end of life of a print cartridge for a thermal ink jet printer determines the status of the print cartridge and warns the user if the print cartridge is at or near the end of its useful life. In a first mode of operation, an initial temperature of a printhead contained in the print cartridge is checked after a threshold amount of ink is expelled from the printhead, such as for a high density print swath or during a service routine. This initial temperature is then compared with a maximum initial temperature. If the initial temperature exceeds the maximum initial temperature, a warning about the status of the print cartridge is sent to a user. If the initial temperature does not exceed the maximum initial temperature, the user is informed of the remaining life portion of the print cartridge. In a second mode of operation, a final temperature is checked after a period of time elapses since the threshold amount of ink is expelled from the printhead. This final temperature is then compared to a maximum final temperature. If the final temperature exceeds the maximum final temperature, a warning about the status of the print cartridge is sent to a user. If the final temperature is less than the maximum final temperature, the user is informed of the remaining life portion of the print cartridge. In a third mode of operation, the heat transfer efficiency of the print cartridge is calculated. If the heat transfer efficiency of the print cartridge is below a minimum heat transfer efficiency, a warning about the status of the print cartridge is sent to a user. If the heat transfer efficiency exceeds a minimum heat transfer efficiency, the user is informed of the remaining life portion of the print cartridge.