PTAB

IPR2020-00635

Stahls' Inc v. Schwendimann Jodi

Key Events

Petition

petition Intelligence

Title: Method of Image Transfer on a Colored Base
Brief Description: The ’042 patent discloses a multi-layer image transfer sheet and method for transferring an image onto a colored or dark base, such as fabric. The invention purports to enable a single-step application by integrating a white pigment into one of the sheet's layers to provide an opaque background, preventing the dark base color from obscuring the transferred image.

Prior Art Relied Upon: Asajima (Patent 5,418,207), Oez (Patent 5,665,476).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Asajima taught a multi-layer thermal transfer sheet with various polymer layers (dye-receiving, intermediate, adhesive) and disclosed that incorporating a white pigment into any of these layers provides "excellent whiteness" independent of the substrate color. While Asajima provided the core structure of an "image-imparting member," it did not explicitly describe a "peel first" application method for dark fabrics. Oez supplied this missing element by teaching a transfer paper specifically for dark textiles that uses a "peel first" method where the image-bearing film is peeled from its backing and then applied to the textile.
- Motivation to Combine: A POSITA would combine Asajima's pigmented multi-layer sheet with Oez's "peel first" application method. The motivation stemmed from Oez's explicit teaching that this method was advantageous for transferring images to dark fabrics, a known problem that Asajima's pigmented sheet was designed to address.
- Expectation of Success: A POSITA would have had a reasonable expectation of success in making the combination, as both references operated in the same field of heat transfer sheets and addressed the common goal of improving image quality on various substrates using compatible materials and processes.

Prior Art Relied Upon: Oez (Patent 5,665,476).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner contended that Oez disclosed every element of the challenged method claims. Oez described a heat transfer paper for printing on dark textiles which included a polymeric coating with white pigment (titanium dioxide) to obviate the need for a separate white base coat. Oez's taught method involved printing an image on the coating, peeling the coating as a film away from its carrier paper, placing the film on the textile, and applying heat to bond it. Petitioner asserted this directly mapped to the claimed steps of obtaining an article with an opaque "image-imparting member," peeling the removable substrate, contacting a dark base, and applying heat. Oez also disclosed protecting the film during ironing by placing the removed paper back on top, anticipating limitations in dependent claims.

Prior Art Relied Upon: Williams (Patent 6,875,487).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Williams disclosed a "heat-setting label sheet" that anticipated the claimed method. Williams taught a multi-layer sheet with an image-receiving layer, an opaque layer, and an adhesion layer on a removable support. The reference specified that the opaque layer could include white pigment to "render the image visible against a dark receptor." The method described in Williams involved peeling the functional layers from the support base and then using a heating device (e.g., an iron) to apply the label to the receptor element, which explicitly included textiles. Petitioner also asserted that Williams' teaching that the adhesion and opaque layers "melt and flow" upon heating met the "melt and mix" construction required by prosecution history.
Additional Grounds: Petitioner asserted additional obviousness challenges against claims 16-22 based on combinations including DeVries (Patent 4,058,644) or Keino (Patent 4,515,849) with Oez, arguing these primary references also taught multi-layer transfer sheets with opacifying agents for use on colored fabrics.

Petitioner argued that the terms "white layer" and "image-imparting member" required a specific construction based on prosecution history estoppel arising from a prior Interference proceeding involving the ’042 patent.
Based on the Patent Owner's alleged "clear and unmistakable" disavowal during that proceeding to distinguish the claims from prior art, Petitioner contended the terms must be construed to require "a polymer that melts and mixes with another layer or layers during application." This construction was central to Petitioner's arguments that the prior art, which disclosed compatible adjacent polymer layers that would inherently melt and mix under heat and pressure, met all claim limitations.

Petitioner requested the institution of an inter partes review and cancellation of claims 16-22 of the ’042 patent as unpatentable.