Invalidity dossier
US 4506272
Thermal printing head
Current assignee: Panasonic Holdings Corp
Added 9/23/2026, 11:04:53 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 — US4506272A
Title: Thermal printing head
Patent number: US4506272A
Application number: US06/439,643
Inventor: Shoji Arai
Original assignee: Matsushita Electric Industrial Co., Ltd. (current assignee listed as Panasonic Holdings Corp)
Prior art date: 1981-11-06
Filing date: 1982-11-05
Publication (grant) date: 1985-03-19
Legal status: Expired – Lifetime
Purpose. The invention addresses a thermal printing head that integrally combines a heater array with multiple semiconductor devices, each containing a shift register. The stated object is a compact, low-cost head. The excerpt identifies the central difficulties as the electrical connections between numerous arrayed heaters and the semiconductor devices, and the formation of head terminals — both of which affect head shape, apparatus design, manufacturing cost, and reliability.
Plain-language scope. A set of straight lead wires, supported on an electrically insulating flexible film, and a set of L-shaped or inverted L-shaped lead wires are formed by a TAB (tape automated bonding) method. One end of each straight lead wire connects to one end of a heater in the array, and the other end connects to one end of a semiconductor device. One end of each L-shaped/inverted L-shaped lead wire connects to the other end of a semiconductor device, and the other end connects to one of a set of multi-layer conductors, part of each being formed in a multi-layer. The excerpt states this construction permits a head terminal formation applicable under various head operating conditions. The semiconductor device includes npn transistors, a gate circuit, buffers, and a shift register performing serial-parallel conversion.
Not established by the excerpt. The full text is omitted; therefore the complete claims, their exact scope and limitations, all drawing details, and the full description are not established. No litigation, ownership-transfer, validity, or prior-art conclusions are made or supported here.
Source: https://patents.google.com/patent/[US4506272](/patent/US4506272)/en
Generated 10/1/2026, 9:32:53 PM
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Litigation summary
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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
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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.