Invalidity dossier
US 6880921
Inkjet cartridge with tubular entrained ink chamber
Current assignee: Hewlett Packard Development Co LP
Added 9/23/2026, 10:13:55 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 6,880,921 B2
Title: "Inkjet cartridge with tubular entrained ink chamber"
Assignee: Hewlett-Packard Development Company, L.P. (original assignee, per the provided record; an earlier assignment to Hewlett-Packard Company is also noted).
Inventors: Mirayda A. Aponte and Julio A. Rodriguez-Mojica.
Key dates (as listed): Filed 2002-09-12; priority date 2002-09-12; published as US 2004/0051765 A1 on 2004-03-18; granted 2005-04-19. Status: "Expired - Lifetime"; adjusted expiration 2022-12-22. Related filings noted: JP 2003-314155 (JP 4220338 B2) and US 10/845,957 (US 7,029,108 B2).
Purpose: The disclosure concerns thermal inkjet printers and their ink cartridges — specifically, cartridges using foam (e.g., open-cell urethane) in which ink is "entrained" by capillary attraction. The text explains the general inkjet context: a nozzle assembly with capillary passages and selectively controlled heaters that vaporize ink to fire droplets, and the role of foam in creating "back pressure" to prevent drooling, while a vent system lets air displace consumed ink.
Plain-language scope (from the excerpt): The excerpt states the invention "pertains to thermal inkjet printers, and more specifically, to ink cartridges employed in conjunction therewith." It distinguishes prior-art configurations: (a) a single reservoir substantially filled with foam, and (b) a two-chamber design with a free-ink chamber and an entrained-ink chamber separated by a generally flat, rigid panel/barrier, with a port near the bottom allowing ink migration and a vent near the top of the entrained-ink chamber. The title indicates a "tubular" entrained ink chamber, but the excerpt provided describes only the rectilinear prior-art barrier arrangement and does not set out the tubular structure.
Classification: B41J 2/17513 (ink cartridges — inner structure).
Not established by this excerpt: No claims, detailed description of the tubular chamber, figures, or claim language are included. Nothing here establishes validity, enforceability, litigation history, or ownership changes beyond the recorded assignments shown.
Generated 10/1/2026, 9:33:40 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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