Invalidity dossier
US 5671001
Leak resistant ink containment for a printer
Current assignee: Hewlett Packard Development Co LP
Added 9/23/2026, 9:24:34 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 5,671,001 — "Leak resistant ink containment for a printer"
Bibliographic data (from supplied text). U.S. Patent 5,671,001 (application US08/397,823) was filed March 3, 1995, and published/granted September 23, 1997. Inventors listed: Joseph R. Elliot, J. Paul Harmon, Naoto Kawamura, and John M. Altendorf. Original assignee: Hewlett-Packard Co.; current assignee listed: Hewlett Packard Development Co LP. Status listed: Expired – Lifetime (anticipated expiration March 3, 2015). Earlier priority filings are listed to GB9514896A and DE19531361A. Classifications include B41J2/17513 (ink cartridge inner structure) and B41J2/17553 (outer structure).
Purpose. The patent addresses a foam-based ink containment system for inkjet print cartridges, including multi-color cartridges. Air trapped in foam (as many small bubbles) expands with temperature or atmospheric pressure changes, displacing ink and causing unwanted "drool" or leakage from printhead orifices—potentially depositing one color's ink onto the printhead.
Plain-language scope. The described ink container has an ink inlet near a first end, first and second opposing walls between the first end and a second end, and a porous member (foam) extending from the first end toward the second end, compressed between the opposing walls. A plurality of relief pockets is disposed in a surface of the first wall, each with a bottom recessed from that surface by a depth such that the compressed porous member does not follow the relief pocket contour. At least one vent channel communicates with at least a portion of the relief pockets and extends from the first end toward the second end. The description notes foam is compressed (increasing capillary force) and that ink fill holes are plugged by vent plugs allowing pressure equalization. It distinguishes extended vertical ribs (e.g., Canon BCI-21) as permitting ink to flow back to fill holes.
Source: https://patents.google.com/patent/US5671001/en
What the excerpt does not establish. It gives no full claim language, no complete figure descriptions, no prior-art analysis, and no litigation, validity, or ownership-transfer details. The excerpt also omits portions of the specification (it is explicitly marked as excerpted), and the bibliographic status and assignee entries are disclaimed as assumptions, not legal conclusions.
Generated 10/1/2026, 9:34:19 PM
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Litigation summary
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PTAB challenges
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Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
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Obviousness
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Extensions
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Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.