Invalidity dossier
US 6309053
Ink jet printhead having a ground bus that overlaps transistor active regions
Current assignee: Hewlett-Packard Company, Hewlett-Packard Development Company, L.P.
Added 9/24/2026, 12:00:58 AM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US6309053B1
Title: Ink jet printhead having a ground bus that overlaps transistor active regions
Patent number: US6309053B1 | Application: US09/621,922 | Inventors: Joseph M. Torgerson, David M. Hurst
Assignee: Original assignee Hewlett Packard Co.; current assignee listed as Hewlett Packard Development Co LP (the source notes listed assignees "may be inaccurate").
Dates (as listed; the source states priority date is an assumption): Priority/filing date 2000-07-24; publication/grant 2001-10-30; anticipated expiration 2020-07-24. Legal status: Expired – Lifetime.
Purpose. The patent "generally relates to ink jet printing, and more particularly to a thin film ink jet printhead having FET drive circuits configured to compensate for parasitic power dissipation along a ground bus." The disclosed invention "is directed to an ink jet printhead having a ground bus that partially overlies active regions of heater resistor energizing FET drive circuits."
Plain-language scope (from the supplied text). A typical Hewlett-Packard ink jet printhead has nozzles in an orifice plate attached to an ink barrier layer, itself attached to a thin film substructure implementing ink firing heater resistors and apparatus for enabling them. The thin film substructure comprises a silicon substrate with thin film layers forming the resistors, enabling apparatus, and interconnections to bonding pads for external connections. Ink chambers over the resistors, with adjacent substructure and orifice plate portions, form ink drop generator regions. The stated improvement concerns the layout of the FET drive circuit array and its associated ground bus (see FIGS. 4, 6, 8), depicted by an electrical schematic of a heater resistor and FET drive circuit (FIG. 5) and an elevational cross section of a representative FET drive circuit (FIG. 7). The source also lists a printer (FIG. 9) in which the printhead can be employed.
What the excerpt does not establish. It provides no claim text, so the exact claimed scope is not established here. It does not establish details of the FET/ground-bus geometry, fabrication steps, or electrical performance. It does not establish validity, infringement, or the substance of the listed litigation or assignments.
Source: https://patents.google.com/patent/[US6309053](/patent/US6309053)/en
Generated 10/1/2026, 9:32:11 PM
Cases on file (2)
Group view →Specific litigation cases in our database that name US patent 6309053. The free-form analysis below may also discuss cases beyond this list.
- Hewlett-Packard Company et al. v. MicroJet Technology Co., Ltd. et al.filed May 25, 2010337-TA-723U.S. International Trade Commission, Washington, D.C.terminated Oct 24, 2011Violation found; general exclusion order issued; investigation terminated
Defendants: MicroJet Technology Co., Ltd., Asia Pacific Microsystems, Inc., Mipo Technology Limited, and 4 others
Other patents asserted: 6481817, 6234598, 6398347, 6402279, 6412917
- Hewlett-Packard Company v. MicroJet Technology Co., Ltd. et al.filed Mar 5, 2010337-TA-711U.S. International Trade CommissionInstituted; '817 inclusion probable but unverified
Defendants: MicroJet Technology Co., Ltd., Mipo Technology Limited, Mipo Science & Technology Co., Ltd., and 3 others
Other patents asserted: 6481817, 6234598, 6398347, 6402279, 6412917
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.
Current assignee: Hewlett-Packard Company, Hewlett-Packard Development Company, L.P.
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.
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This patent in court (2)
2 tracked lawsuits name US 6309053.