PTAB

IPR2020-01122

Stahls' Inc v. Schwendimann Jodi

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Image Transfer on a Colored Base
  • Brief Description: The ’475 patent is directed to a multi-layer image transfer sheet, commonly known as an "iron-on," and a method for its use. The technology aims to improve image transfers onto colored or dark substrates by integrating an opaque white layer into the transfer sheet, thereby creating a white background in a single application step.

3. Grounds for Unpatentability

Ground 1: Obviousness of Claims 1-3, 5-15, and 18 over Akada in view of Takao

  • Prior Art Relied Upon: Akada (Patent 5,248,543) and Takao (Patent 5,753,589).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Akada taught a multi-layer image transfer sheet with nearly all claimed elements, including a substrate, an intermediate layer comprising polyurethane, and an image-reception layer also comprising polyurethane. However, Akada disclosed admixing a white pigment directly into its image-reception layer. The challenged claims require a separate "opaque first layer" containing the pigment, distinct from the "second layer" that receives the image. Petitioner contended that Takao supplied this missing element by explicitly teaching a thermal transfer sheet with a discrete "whiteness-improving layer" separate from the receptive layer.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would have been motivated to modify Akada’s transfer sheet by incorporating Takao’s separate whiteness-improving layer. Petitioner asserted that Takao expressly disclosed that using an independent white layer improves whiteness without sacrificing the quality and fastness of the image—a known trade-off when pigment is mixed directly into the receptive layer. As both references address the same problem in the same field, this combination was presented as a predictable solution to a known problem.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the references. Both Akada and Takao employed similar materials (e.g., polyurethanes, titanium dioxide) and heat-transfer processes. Therefore, integrating Takao's separate pigmented layer into Akada's structure would predictably yield the benefits described by Takao without disrupting the overall function of the transfer sheet.

Ground 2: Obviousness of Claim 4 over Akada in view of Takao and Kronzer

  • Prior Art Relied Upon: Akada (Patent 5,248,543), Takao (Patent 5,753,589), and Kronzer (Patent 5,242,739).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination of Akada and Takao. Claim 4 adds the limitation that a "third layer" (a hot-melt adhesive layer) comprises specific fillers, such as a "heat fusion reducing filler" or an "adhesion altering filler." Petitioner argued that while the Akada/Takao combination provided the basic layered structure, Kronzer taught the use of these specific additives. Kronzer disclosed a multi-layer heat transfer paper where various processing aids and fillers are included in the layers to improve properties like melt-flow and achieve a smooth film upon transfer.
    • Motivation to Combine: The motivation to add Kronzer was to optimize the performance of the hot-melt layer in the Akada/Takao combination. A POSITA seeking to improve the physical properties and application characteristics of the transfer sheet would have been motivated to incorporate the well-known fillers and processing aids taught by Kronzer to achieve a better final product.

Ground 3: Anticipation of Claims 13-15 and 18 by Asajima

  • Prior Art Relied Upon: Asajima (Patent 5,418,207).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Asajima, standing alone, disclosed every element of these claims under 35 U.S.C. §102. Asajima taught a thermal transfer image-receiving sheet comprising a dye-receiving layer, an intermediate layer, and an adhesive layer, all on a releasable sheet. Crucially, Petitioner highlighted Asajima’s teaching that "incorporation of a filler, a white pigment... in at least one of the above-described layers can provide a receiving layer having an excellent whiteness independently of the ground color of the transfer material." Petitioner contended that placing this white pigment in Asajima’s intermediate layer or adhesive layer would satisfy the claims’ requirement for an "opaque white layer" that is separate from the primary ink-receptive layer.

  • Additional Grounds: Petitioner asserted additional challenges, including obviousness of claim 19 over Akada, Takao, and either Hare (Patent 5,948,586) or Oez (Patent 5,665,476) for teaching the use of protective sheets during heat transfer. Further grounds alleged obviousness of claims 13, 15, 16, and 18 based on combinations of Asajima, Kronzer, Oez, and Takao, relying on similar rationales for combining known elements to achieve predictable results.

4. Key Claim Construction Positions

  • Petitioner dedicated significant argument to the construction of the term "white layer" (and its equivalents in the claims, e.g., "opaque first layer").
  • Based on alleged prosecution history disavowal during a prior interference proceeding (Interference No. 109,966), Petitioner argued that any claimed "white layer" must be construed to require that its polymer component "must melt and must mix" with another layer during application.
  • The proposed construction was: "a layer comprising a concentration or configuration of pigment providing a white background for received indicia and which further comprises a polymer that melts and mixes with another layer or layers during application." This construction was asserted to be critical, as it aligns the claimed invention with the inherent properties of the prior art, which disclosed similar polymeric materials used at similar heat-transfer temperatures.

5. Relief Requested

  • Petitioner requested the Board institute an inter partes review of claims 1-16 and 18-19 of the ’475 patent and cancel all challenged claims as unpatentable.