DCT
5:25-cv-01772
Kingmark Mfg Co v. Ningbo Xinrun Textile Co Ltd
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Kingmark Manufacturing Company (California)
- Defendant: Ningbo Xinrun Textile Co., Ltd. (China) and Machimpex USA, LLC (Massachusetts)
- Plaintiff’s Counsel: Hawkinson Yang LLP
- Case Identification: 5:25-cv-01772, C.D. Cal., 07/14/2025
- Venue Allegations: Plaintiff alleges venue is proper because its principal place of business is in the Central District of California, and Defendants purposefully directed patent enforcement activities into the district.
- Core Dispute: Plaintiff seeks a declaratory judgment that its microfiber cleaning products do not infringe Defendants' patent, and that the patent is invalid and unenforceable.
- Technical Context: The technology concerns the manufacturing of continuous textile cloths with integrated tear-off perforations created by ultrasonic melting.
- Key Procedural History: The complaint alleges that this action was precipitated by Defendants' use of Amazon's "Report Infringement" system to accuse Plaintiff of infringement. The complaint further alleges that the U.S. patent's corresponding Chinese counterpart patent was invalidated by Chinese authorities for lack of inventiveness. It also raises questions of improper inventorship, alleging that a U.S. inventor was added to the patent nearly two years after the priority application was filed in China.
Case Timeline
| Date | Event |
|---|---|
| 2022-03-24 | Chinese Priority Application Filed ('354 Patent) |
| 2022-07-05 | U.S. Application for '354 Patent Filed |
| 2024-03-21 | Request to add Robert Poirier as inventor on U.S. Application |
| 2024-04-28 | Chinese Counterpart Patent allegedly invalidated by Chinese authorities |
| 2025-01-28 | U.S. Patent No. 12,209,354 Issued |
| 2025-05-02 | Defendants allegedly file Amazon infringement notice against Plaintiff |
| 2025-07-14 | Complaint for Declaratory Judgment Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 12,209,354 - "CONTINUOUS POLYESTER FIBER TEXTILE CLOTH, PROCESSING EQUIPMENT AND METHOD," issued January 28, 2025
The Invention Explained
- Problem Addressed: The patent's background notes that conventional manufacturing of textile cloths, such as for wiping, requires cutting continuous fabric into individual sheets, a process that involves multiple steps, high production costs, and is inconvenient for end-users (’354 Patent, col. 1:39-45).
- The Patented Solution: The invention is a continuous roll of polyester fiber cloth featuring "thin line melting bodies" at set intervals, which act as perforations (’354 Patent, Abstract). These lines are created using an "ultrasonic hot-melting technology" where a metal knife mold and an ultrasonic welding head resonate together, generating a localized "linear high temperature zone" that melts the fabric threads to form a tearable seam (’354 Patent, col. 4:13-22). This allows a user to tear off single pieces from the continuous roll.
- Technical Importance: This method aims to simplify the production and packaging of products like cleaning towels by creating a continuous roll with built-in tear-off points, potentially reducing manufacturing costs by eliminating separate cutting and stacking steps (’354 Patent, col. 1:49-56).
Key Claims at a Glance
- The complaint identifies Claim 1 as the sole independent claim asserted (’354 Patent, col. 9:1-13; Compl. ¶15).
- Essential elements of Independent Claim 1 include:
- A continuous polyester fiber textile cloth comprising a base layer and a loop layer.
- A plurality of "thin line melting bodies" at intervals, which allow a single piece of cloth to be separated by tearing.
- The melting bodies are formed by heating and melting the base and loop layers using "high-frequency ultrasonic waves."
- The process of using high-frequency ultrasonic waves comprises a specific "heating temperature of an ultrasonic welding head being 150-400° C."
- The process also comprises "a duration for a knife edge to press down and contact the polyester fiber textile cloth being 0.02-1 second."
- The complaint asserts non-infringement of all dependent claims based on the non-infringement of Claim 1 (Compl. ¶24).
III. The Accused Instrumentality
Product Identification
- The accused products are "microfiber cleaning cloth products" sold by Plaintiff Kingmark Manufacturing Company on its "LULUCATCH Amazon storefront" (Compl. ¶¶7, 9).
Functionality and Market Context
- The complaint does not describe the specific manufacturing process of Kingmark's products. Instead, it makes a direct denial that the products are made using the process claimed in the '354 Patent (Compl. ¶23). The complaint alleges that Defendants' infringement accusations are intended to "force competing products off of Amazon" and interfere with Kingmark's business (Compl. ¶¶11, 20).
- No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint seeks a declaratory judgment of non-infringement. The following table summarizes Kingmark's asserted basis for its non-infringement position as alleged in the complaint.
'354 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged (Non-)Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| wherein being heated and melted by high-frequency ultrasonic waves comprises a heating temperature of an ultrasonic welding head being 150-400° C. | Kingmark alleges its products "do not meet the claim limitations of claim 1," including the required heating temperature of an ultrasonic welding head. | ¶23 | col. 9:9-11 |
| and a duration for a knife edge to press down and contact the polyester fiber textile cloth being 0.02-1 second. | Kingmark alleges its products do not meet the limitation requiring a specific duration for a knife edge to press down and contact the cloth. | ¶23 | col. 9:11-13 |
| wherein the base layer and the loop layer(s) are heated and melted by high-frequency ultrasonic waves; | Kingmark alleges its products do not meet the limitation requiring the use of "high-frequency ultrasonic waves." | ¶23 | col. 9:7-8 |
Identified Points of Contention
- Factual Question: The central dispute appears to be a factual one regarding Kingmark's manufacturing process. The case will require evidence establishing whether Kingmark's process uses ultrasonic welding and, if so, whether the operational parameters (temperature, duration, frequency) fall within the ranges specified in Claim 1.
- Evidentiary Question: The complaint alleges that Defendants have not provided any evidence that Kingmark infringes (Compl. ¶22). A key question for the court may be what pre-suit investigation, if any, Defendants conducted before filing infringement reports on Amazon's platform.
V. Key Claim Terms for Construction
The Term: "high-frequency ultrasonic waves"
Context and Importance: This term defines the energy source for the claimed melting process. Kingmark specifically denies that its products are made using this method (Compl. ¶23). The construction of this term will therefore be critical to determining infringement.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party might argue the term should be given its plain and ordinary meaning, covering any ultrasonic frequency sufficient to melt the specified fabric.
- Evidence for a Narrower Interpretation: The specification provides a specific, narrowing definition in a preferred embodiment, stating "a vibration frequency of the ultrasonic welding head is 2000-50000 times/second" (’354 Patent, col. 3:13-16). This provides strong intrinsic evidence to construe the term as being limited to this frequency range.
The Term: "thin line melting body"
Context and Importance: This term describes the resulting structure that enables the cloth to be torn. Its definition is central to the claimed invention. Practitioners may focus on this term because its construction will dictate the physical characteristics a product must have to infringe.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language broadly defines it as a body formed by "heating, melting and pressing" that allows for tearing (’354 Patent, col. 9:1-6).
- Evidence for a Narrower Interpretation: The specification describes the "thin line melting body" as a "tearing notch" where fibers are "thermally damaged and become brittle" (’354 Patent, col. 6:5-14). Preferred embodiments also provide specific dimensions, such as a thickness of 0.01-2 mm and a width of 1-5 mm (’354 Patent, col. 6:56-58), which could be used to argue for a more limited scope.
VI. Other Allegations
- Invalidity: The complaint presents multiple grounds for invalidity, alleging the '354 Patent is invalid under 35 U.S.C. §§ 102 and 103 because its Chinese counterpart was "wholly invalidated...for lack of inventiveness over the prior art" (Compl. ¶¶19, 32). It further alleges invalidity for incorrect inventorship under 35 U.S.C. §§ 115 and 256, based on the allegedly improper addition of a U.S. inventor, Robert Poirier, who was not listed on the Chinese priority application (Compl. ¶33).
- Unenforceability / Inequitable Conduct: The complaint alleges that the '354 Patent is unenforceable due to inequitable conduct. The basis for this claim is the allegation that Mr. Poirier was improperly added as an inventor through a declaration to the USPTO that was "falsely stated" and violated the duty of candor (Compl. ¶37).
- Unfair Competition: Plaintiff brings a claim for unfair competition under California law, alleging Defendants asserted the '354 Patent via Amazon's reporting system in bad faith, knowing it was likely invalid or not infringed, in an effort to "thwart Kingmark's business" (Compl. ¶¶38, 41).
VII. Analyst’s Conclusion: Key Questions for the Case
- A primary issue will be one of validity and foreign proceedings: how will the alleged invalidation of the '354 Patent's Chinese counterpart for lack of inventiveness affect the validity of the U.S. claims? The court will likely have to consider whether the prior art and claims at issue in the Chinese proceeding are substantially the same as those in the U.S. case.
- A second critical issue concerns inventorship and enforceability: did the named U.S. inventor, Robert Poirier, make a contribution sufficient to be named on the patent? If not, the inquiry may shift to whether his addition involved the submission of false information to the USPTO with deceptive intent, which could render the entire patent unenforceable.
- Finally, should the patent survive these challenges, a central evidentiary question will be one of process comparison: does Kingmark's manufacturing process for its microfiber cloths, as a matter of fact, employ the specific ultrasonic heating parameters—including temperature, pressure duration, and frequency—recited in Claim 1 of the '354 Patent?