Invalidity dossier
US 4567493
Liquid jet recording head
Current assignee: Canon Inc
Added 9/17/2026, 1:16:00 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US4567493A
Title: Liquid jet recording head
Patent number: US4567493A
Application number: US06/598,974
Inventors: Masami Ikeda; Hiroto Matsuda; Makoto Shibata; Hiroto Takahashi
Original/current assignee: Canon Inc. (assignment recorded to Canon Kabushiki Kaisha, a corp. of Japan)
Prior art date: 1983-04-20 (listed as an assumption, not a legal conclusion)
Filing date: 1984-04-11
Publication/grant date: 1986-01-28
Legal status: Expired – Lifetime; anticipated expiration 2004-04-11 (status listed as an assumption, not a legal conclusion)
Purpose: The patent addresses a liquid jet recording head. According to the excerpted text, its recurring concern is a protection layer — specifically an "upper protection" layer — on the recording head, intended to shield head components from the liquid being discharged. The excerpt indicates the disclosure deals with deterioration, defect, penetration, and shock in long-term repetitive use, and with organic and inorganic materials, resins, metals, oxides, nitrides, and the like as candidate layer materials.
Plain-language scope: In general terms, the patent describes a liquid jet recording head in which an upper protection layer is provided over head structure to protect it from the liquid. The excerpt shows the claimed subject matter centers on the protection layer, the material(s) forming it (organic materials such as resins including polyimide, and inorganic materials such as metals, oxides, nitrides, silicides, and glasses), and a method of making the head. Fewer than a handful of terms dominate the claims, abstract, and description (liquid, material, inorganic material, organic material, discharging), which is consistent with a focus on layer composition and protection rather than on overall printer architecture.
What the excerpt does not establish:
- The full text of any claim, the claim count, or the exact claim language.
- The complete specification, examples, or figures (the excerpt omits an indeterminate amount of text and figure descriptions).
- The specific identity of the "upper protection" layer, its thickness, or its deposition sequence.
- Any statement about validity, enforceability, or the scope of prior art.
- Any litigation, licensing, or ownership-transfer history.
Source: https://patents.google.com/patent/[US4567493](/patent/US4567493)/en
Generated 10/1/2026, 10:03:16 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.