HP Inc v. Memjet Technology Ltd

1. Case Identification

• Case #: IPR2016-00790
• Patent #: 8,678,550
• Filed: March 22, 2016
• Petitioner(s): HP Inc.
• Patent Owner(s): Memjet Technology Limited
• Challenged Claims: 1-4

2. Patent Overview

• Title: Printhead Assembly with Laminated Ink Distribution
• Brief Description: The ’550 patent relates to a pagewidth inkjet printhead assembly that includes an ink distribution system for supplying multiple inks to an array of replaceable printhead modules. The system utilizes a laminated stack of thin sheets with precisely positioned holes and slots that, when bonded together, form channels to distribute ink from a molding to the printhead chips.

3. Grounds for Unpatentability

Ground 1: Claims 1-3 are obvious over Boyd in view of Waller

• Prior Art Relied Upon: Boyd (Patent 6,322,206) and Waller (Patent 6,250,738).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the combination of Boyd and Waller discloses every element of claims 1-3. Boyd was asserted to teach a printhead with a multi-layered substrate (a "laminated ink distribution stack") that distributes multiple inks to a staggered, overlapping array of printhead dies. Petitioner contended that Waller, a continuation-in-part of Boyd, supplies the remaining key elements of claim 1: an "ink distribution molding" (Waller's manifold 33), "transitional ducts" that carry ink from the molding to the stack (Waller's fill openings 61a-c), and a "cover" with corresponding ink inlets (Waller's housing 82 with inlets 37). For dependent claim 2, Petitioner asserted that the intermediate layers of Boyd's substrate disclose the required "plurality of ink slots and ink holes." For dependent claim 3, Petitioner argued that the longitudinally extending channels in Waller's manifold extend across a pagewidth.
  • Motivation to Combine: A POSITA would combine these references because they are directed to highly similar inkjet technologies and Waller is a continuation-in-part of Boyd. Petitioner argued a POSITA would be motivated to incorporate Waller's molded manifold ink delivery system into Boyd's design to more effectively distribute ink across an extended pagewidth and to supply ink to Boyd's multiple subassemblies without feeding ink to the seams between them.
  • Expectation of Success: Given the technical compatibility and shared lineage of the references, a POSITA would have had a high expectation of success in combining their respective features to achieve a more robust and efficient pagewidth printing system.

Ground 2: Claim 4 is obvious over Boyd and Waller in view of Ayata

• Prior Art Relied Upon: Boyd (Patent 6,322,206), Waller (Patent 6,250,738), and Ayata (Patent 4,463,359).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addresses dependent claim 4, which adds the limitation that "the assembly is supported by metal chassis." Petitioner asserted that the printhead assemblies of Boyd and Waller are both supported by a "mounting assembly." The tertiary reference, Ayata, was introduced for its explicit teaching of mounting staggered inkjet head blocks on a metal substrate (chassis).
  • Motivation to Combine: A POSITA would be motivated to fabricate the mounting assembly of the primary Boyd/Waller combination from metal, as taught by Ayata, for several well-understood benefits. These motivations included providing rigid structural support for the pagewidth assembly, creating an effective heat sink to manage heat from the thermal inkjet components, and using a material that is inexpensive and easy to manufacture for such structural components.
  • Expectation of Success: Modifying the known mounting assembly by fabricating it from a well-known material like metal for its known properties would have been a simple and predictable design choice with a clear expectation of success.

4. Key Claim Construction Positions

• "laminated ink distribution stack": Petitioner proposed this term be construed as "an ink distribution structure manufactured by layering thin, flat sheets one on top of the other and gluing or otherwise bonding them together." This construction was argued to be consistent with the ’550 patent’s specification, which describes the stack as comprising a number of individual layers that are glued or bonded to form a sealed unit.
• "transitional ducts": Petitioner proposed this term be construed as "channels for carrying ink from one structure to an adjoining structure." This was based on the specification's disclosure that ink travels from the "ink distribution molding" through a "transfer port" to the "laminated stack," fulfilling a transitional role between the two distinct components.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that institution was proper despite the examiner having previously considered the Boyd reference during prosecution of the ’550 patent. The petition asserted that the examiner never considered the specific combination of Boyd and Waller, nor the combination of Boyd, Waller, and Ayata. Therefore, the arguments and prior art presented in the petition were substantially different from those previously evaluated by the USPTO, making review appropriate under 35 U.S.C. § 325(d).

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-4 of Patent 8,678,550 as unpatentable under 35 U.S.C. § 103.