US 7938523

Search verification

I searched for the specific number 7938523 (and its PTAB/CAFC litigation dockets). All results confirmed the correct patent — U.S. Patent No. US7938523B2, Application No. 11/762,101 — and I did not conflate it with similarly numbered patents. The USPTO/PTAB materials (e.g., the IPR2022-01416 record) repeatedly identify "U.S. Patent No. 7,938,523," Application No. 11762101, titled "FLUID SUPPLY TANK VENTILATION FOR A MICRO-FLUID EJECTION HEAD" (source: ptacts.uspto.gov document download; portal.unifiedpatents.com IPR case page).

Concise patent summary

Title: Fluid supply tank ventilation for a micro-fluid ejection head

Inventor: Charles Stanley Aldrich (sole inventor; Nicholasville, KY per PTAB records)

Assignee history (per assignment records / Google Patents):

• Original assignee: Lexmark International, Inc. (assignment recorded June 13, 2007)
• Later: Funai Electric Co., Ltd. (assignment effective April 1, 2013)
• Current listed assignee: Slingshot Printing LLC (assignment effective March 29, 2019)

Filing date: June 13, 2007 (U.S. Application No. 11/762,101, utility under 35 U.S.C. § 111(a))

Issue date: May 10, 2011

Legal status: Active (Google Patents shows adjusted expiration of March 7, 2030; maintenance fees paid through the 12th year).

Abstract (verbatim): "An improved fluid supply tank for a micro-fluid ejection head and method for improving operation of a micro-fluid ejection device. The fluid supply tank has a body portion for holding a fluid to be ejected. The body portion includes a fluid exit port on an exit end thereof and a cover on an opposing end thereof. An internal vent conduit is disposed in the tank between the exit end and the cover for air removal adjacent to the exit port."

Technology in brief: The patent addresses trapped air adjacent to the connection between a replaceable ink/fluid supply tank and a micro-fluid ejection (printhead) structure. When trapped air expands or contracts (due to altitude or atmospheric pressure changes, tank swapping, etc.), it can cause nozzle seepage, air ingestion, or cross-contamination in multi-color systems. The solution is an internal vent conduit inside the tank running between the exit-port end and the top cover, which has a serpentine atmospheric vent. Air near the exit port is channeled around the capillary felts and out through the cover vent, avoiding the need for large air-collection volumes or purge/maintenance stations. Dimensions of ~0.5–2 mm (width and depth), optional hydrophobic/hydrophilic coatings, and disposable-head embodiments are described.

Plain-language overview of the independent claims

There are 18 claims total; the independent claims are claim 1 (apparatus) and claim 10 (method).

Claim 1 — Fluid supply tank (apparatus):
Requires (a) a tank body holding fluid, having a fluid exit port at its exit end and a cover at the opposite end, where the cover has an opening open to the atmosphere; (b) an internal vent conduit running between the exit end and the cover, for removing air near the fluid exit port and releasing it through the cover to the atmosphere; and (c) an air space in the fluid exit port, with the vent conduit in air-flow communication with both that air space and the cover.
Plain meaning: An ink tank with an internal air channel built in from near the outlet port up to a top cover that vents to outside air, so air trapped at the outlet can escape to the atmosphere instead of disturbing printhead fluid pressure.

Claim 10 — Method of enhancing operation of a micro-fluid ejection device:
Requires (a) disposing an internal vent conduit in a fluid supply container, in air-flow communication between an air space at the container's fluid-exit end and the container cover (opposite the exit end, with an opening to the atmosphere); and (b) installing the container on the micro-fluid ejection device so trapped air between container and device is urged through the internal vent conduit and out through an atmospheric vent in the cover.
Plain meaning: A method of fitting/installing a vented fluid container so any air trapped at the container/device interface is pushed through an internal channel and exhausted through the top cover's atmospheric vent.

Related proceedings (relevant to CAFC/USPTO docket searches)

• IPR2022-01416 — Canon U.S.A., Inc. and Canon Inc. v. Slingshot Printing LLC, PTAB. Petition filed August 23, 2022; institution granted April 13, 2023; Final Written Decision issued April 9, 2024; Director Review denied June 6, 2024. Per the hearing transcript, the dispute centered on whether the prior-art "Studer '708" reference's vent conduit anticipated the "internal vent conduit … removing air adjacent to the fluid exit port" limitation of the independent claims. Status is listed as "Final Written Decision Appealed."
• CAFC Appeal 24-2132 — Slingshot Printing LLC v. Canon U.S.A., Inc. / Canon Inc. Docketed July 26, 2024; oral argument held May 6, 2026; the CAFC website lists a nonprecedential Rule 36 judgment posted on or about May 7, 2026, affirming the PTAB decision (source: cafc.uscourts.gov notice for 24-2132). IPWatchdog reporting characterizes the underlying PTAB final written decisions as finding Slingshot claims unpatentable as obvious.

Uncertainty notes

• Date discrepancy: Your prompt states "Current Date: April 26, 2026," but the live CAFC website search results show the Rule 36 judgment in 24-2132 was posted May 7, 2026 — after that date. Per the operating rule that live search results are ground truth, I am reporting the May 2026 posting; please reconcile the apparent date mismatch on your end.
• I confirmed that a Final Written Decision and Rule 36 affirmance exist, but I did not retrieve the full FWD text within these searches, so I cannot state with certainty the exact claim-by-claim unpatentability outcome (which specific claims of the 18 were cancelled) or the precise grounds (anticipation vs. obviousness) for every claim.
• The Rule 36 judgment is a summary affirmance without opinion; the "Unified Patents" and Justia docket pages confirm case number 24-2132 and party/attorney details (Mark Borsos for Slingshot; Dion Bregman for Canon).

Key sources: patents.google.com/patent/US7938523B2; freepatentsonline.com/7938523.html; ptacts.uspto.gov IPR2022-01416 records; portal.unifiedpatents.com/ptab/case/IPR2022-01416; cafc.uscourts.gov (24-2132 Rule 36 judgment, May 7, 2026); dockets.justia.com/docket/circuit-courts/cafc/24-2132.