PTAB

IPR2020-00645

Stahls' Inc v. Schwendimann Jodi

Key Events

Petition

petition

Title: Image Transfer on a Colored Base
Brief Description: The ’581 patent discloses a multi-layer image transfer article, or "iron-on," for applying images to colored or dark fabrics. The invention integrates a white pigment into one or more layers of the transfer sheet to create an opaque background, eliminating the need for a conventional two-step process where a white background is applied to the fabric first.

Prior Art Relied Upon: Keino (Patent 4,515,849).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Keino discloses every element of the challenged claims. Keino teaches a thermal transfer sheet comprising a base sheet (removable substrate), a releasing resin layer (coating), and a "pattern layer" (image-imparting member). Critically, Keino describes that this pattern layer can be a composite subdivided into a colored pigment bottom sub-layer (for the indicia) and a white pigment top sub-layer. When transferred, this white sub-layer, containing pigments like titanium oxide, provides the claimed opaque background for the indicia on a colored textile. Keino also discloses suitable coating materials (e.g., silicone, resins) for the release layer. Petitioner asserted that because Keino teaches the same types of polymeric materials and application temperatures as the ’581 patent, the layers would inherently melt and mix during application, satisfying the construction of "opaque background" advanced by the Petitioner.

Prior Art Relied Upon: Oez (Patent 5,665,476).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner contended that Oez's heat transfer paper anticipates the claims. Oez describes a structure with a carrier paper (removable substrate), an optional release layer (coating), and a polymeric coating (image-imparting member). Oez explicitly teaches incorporating a white pigment, such as titanium dioxide, directly into its polymeric coating mixture. This is taught for the express purpose of eliminating the prior need for a separate white coating on dark textiles, allowing a print to be transferred in a single step. Petitioner mapped Oez’s polymeric coating containing white pigment to the claimed "image-imparting member" with an "opaque background." Oez also discloses a silicone release layer and teaches pigment concentrations that fall within the range recited in dependent claim 8.

Prior Art Relied Upon: Oez (Patent 5,665,476) and Takao (Patent 5,753,589).
Core Argument for this Ground:
- Prior Art Mapping: This ground addresses claims requiring a discrete "white layer" separate from the "indicia-receptive layer." Petitioner argued that Oez teaches the basic single-film transfer sheet with a removable substrate, release coating, and an indicia-receptive layer containing white pigment. Takao, in the same technical field, teaches improving image quality by adding a separate, independent "whiteness-improving layer" between the substrate and the receptive layer.
- Motivation to Combine: A POSITA would combine Oez's transfer sheet with Takao's separate whiteness-improving layer to achieve a more effective and distinct opaque background, resulting in a better-quality image on colored fabrics. Takao explicitly states that using an independent layer improves whiteness without sacrificing image quality, providing a clear reason for the combination.
- Expectation of Success: Combining known layers from references in the same field to improve a known quality (opacity/whiteness) would have been a straightforward design choice with a high expectation of success.

Prior Art Relied Upon: Oez (Patent 5,665,476) and Keino (Patent 4,515,849).
Core Argument for this Ground:
- Prior Art Mapping: This ground presents an alternative combination for the claims requiring a separate white layer. Oez provides the foundational heat transfer paper. Keino teaches that a single printable polymer layer can be subdivided into two distinct sub-layers: one that receives the image (indicia) and another that contains white pigment to act as an opaque background.
- Motivation to Combine: A POSITA would have been motivated to modify the single pigmented polymeric layer of Oez by subdividing it into two distinct sub-layers as taught by Keino. This modification would achieve a more effective opaque background for the image, a problem addressed by both references. Both Oez and Keino are in the same technical field of printed heat-transfer sheets and use similar materials.
- Expectation of Success: The modification involves applying a known layering technique (subdividing a layer, from Keino) to an existing product (Oez's sheet) to achieve a predictable improvement, ensuring a reasonable expectation of success.

Petitioner argued that the terms "white layer" and "opaque background" should be construed to require "a polymer that melts and mixes with another layer or layers during application."
This proposed construction was not based on the patent's text but on what Petitioner characterized as a clear and unmistakable disavowal by the Patent Owner during a prior interference proceeding (Interference No. 109,966). In that proceeding, the Patent Owner allegedly distinguished prior art by arguing that the layers in the ’581 patent "must melt, and must combine" to effect the image transfer. Petitioner contended this prosecution history estoppel limits the claim scope and that the prior art references meet this "melt and mix" requirement because they use similar polymers and application temperatures.

Petitioner requests institution of an inter partes review and cancellation of claims 1-6, 8, 11, 12, 17, 19, and 24-26 of the ’581 patent as unpatentable.