Invalidity dossier
US 5144341
Thermal ink jet drivers device design/layout
Current assignee: Xerox Corp
Added 9/23/2026, 9:43:45 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 — US5144341A
Title: Thermal ink jet drivers device design/layout
Patent number: US5144341A
Application number: US07/692,087
Inventors: Abdul M. El Hatem, Steven A. Buhler, Putul D. Patel
Original assignee / current assignee (as listed): Xerox Corp
Priority date: 1991-04-26
Filing date: 1991-04-26
Publication (grant) date: 1992-09-01
Legal status (as listed; not a legal conclusion): Expired – Fee Related; anticipated expiration 2011-04-26
Purpose
The patent relates to thermal ink jet printing systems and, more particularly, to an improved printhead design incorporating multiple levels of interconnection and ballast resistors for the resistive thermal energy generators.
Plain-language scope (from the supplied text)
A thermal printhead has ink-filled channels opening at a nozzle, with heating resistors inside the channels spaced from the nozzle. A current pulse is applied to each resistor to momentarily vaporize ink, forming a bubble that expels a droplet. The excerpt notes that performance depends strongly on the resistor-to-nozzle distance, and that the high packing density needed for high-resolution printing means the electrical front lead connection to one end of the heating resistors must cross the front of the resistor array; the short nozzle-to-resistor distance requires that front lead to be narrower than 120 ppm (the text uses "ppm" in this context). Electrical heating pulses of a few microseconds must dissipate sufficient energy to raise the resistor surface temperature to about 300° C. for bubble nucleation, with typical drop-ejection energies of 10–50 microjoules and about 8 watts dissipated during the pulse.
What this excerpt does not establish
This text is explicitly an excerpt with omitted material. It does not reproduce the full specification, the claims in full, the drawings, or the detailed description of the multiple levels of interconnection and ballast resistors. It identifies no prior-art references, describes no embodiments in full, and provides no claim scope beyond the summary above. It states nothing about litigation, ownership transfers, or validity.
Source: https://patents.google.com/patent/[US5144341](/patent/US5144341)/en
Generated 10/1/2026, 9:34:04 PM
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Litigation summary
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Proceedings on file (0)
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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
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.