Invalidity dossier
US 6252617
Ink jet recording method
Current assignee: Canon Inc
Added 9/23/2026, 8:54:45 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 6,252,617 B1
Title: Ink jet recording method
Patent number: US6252617B1
Application number: US08/067,850
Inventor(s): Kenji Hasegawa; Koichi Toma; Isao Kimura; Atsushi Shiozaki
Original assignee / current assignee (as listed): Canon Inc. / Canon Kabushiki Kaisha
Priority date: 1992-05-29
Filing date: 1993-05-27
Publication/grant date: 2001-06-26
Anticipated expiration: 2018-06-26
Legal status: Expired – Fee Related
Source: https://patents.google.com/patent/US6252617/en
Purpose and plain-language scope
The patent concerns an ink jet recording method. According to the supplied text, the disclosure relates to an ink jet recording head that uses a heating resistor, and to ink used with it. Recurring themes in the excerpt include heating/heat treatment of ink, alkali metal ions and other cationic ions in the ink, and water as a component. The text also associates the invention with heat generation, heat treatment, and the ink jet recording head itself, and mentions materials such as iridium, tantalum, platinum, ruthenium, and various oxides (including ruthenium(IV) oxide) in connection with the description.
The excerpt further indicates discussion of passivation, erosive effects on the recording head, electrochemical reactions, oxidation, and protective effects — suggesting the disclosed method addresses durability or reaction issues at the head/ink interface. The prior-art keywords listed are: ink, ink jet, recording head, jet recording, heating resistor.
No claim text is reproduced in the excerpt, so the precise metes and bounds of the claims cannot be stated from the supplied material.
What the excerpt does not establish
The supplied source is an excerpt. It does not provide the full description, the numbered claims, the abstract, or the drawings. It therefore does not establish the specific claim limitations, the exact ink composition or concentration ranges, the claimed method steps, or the precise relationship between the listed components. It also does not independently establish the accuracy of the listed dates, assignee, or legal status, which the source itself labels as assumptions. No litigation, ownership transfer, validity, or prior-art analysis is presented here, and none should be inferred from this overview.
Generated 10/1/2026, 9:41:04 PM
Cases on file (0)
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Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
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
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.