HP Inc v. Memjet Technology Ltd

1. Case Identification

• Case #: IPR2016-00791
• 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 discloses a pagewidth inkjet printhead assembly featuring replaceable printhead modules. The invention uses a multi-part system, including an ink distribution molding and a connected laminated stack of thin sheets, to distribute multiple inks from various sources to an array of printhead chips for single-pass printing.

3. Grounds for Unpatentability

Ground 1: Claims 1-4 are anticipated under pre-AIA 35 U.S.C. § 102(b) over Silverbrook

• Prior Art Relied Upon: Silverbrook (WO 01/89849 A1).
• Core Argument for this Ground:
  • Priority Date Challenge: A central argument of the petition is that the ’550 patent is not entitled to its purported May 24, 2000 priority date. Petitioner asserted that a predecessor application in the priority chain (Application No. 10/974,751) failed to properly claim priority to an earlier application within the statutory timeframe. The applicant later filed an untimely amendment to correct the priority claim but failed to meet the statutory requirements for accepting such a delayed claim, which included providing evidence that the delay was unintentional and paying a required surcharge. Petitioner argued this failure broke the priority chain, making the ’550 patent’s earliest valid priority date October 28, 2004.
  • Prior Art Mapping: Because the Silverbrook reference was published on November 29, 2001, more than one year before the corrected priority date, Petitioner argued it qualifies as anticipating prior art under §102(b). Petitioner contended that the disclosure of Silverbrook is nearly identical to that of the ’550 patent and teaches every limitation of the challenged claims.
    • Claim 1 (Independent): Petitioner mapped the elements of claim 1 to Silverbrook’s disclosure. It argued Silverbrook teaches a pagewidth printhead assembly with an ink distribution molding (35) comprising longitudinal ink ducts (40) for different colored inks and transitional ducts (51) extending from them. Silverbrook was also shown to disclose a connected laminated ink distribution stack (36) comprising a plurality of bonded layers (52, 56, 60, 62, 64), with the uppermost layer (52) having inlets (ink holes 53) to receive ink from the transitional ducts. Further, Petitioner argued Silverbrook discloses a cover (39) with ink inlet ports (34) corresponding to each ink duct and a plurality of print chips (27) arranged in a staggered, overlapping configuration across a pagewidth. Finally, Petitioner asserted Silverbrook shows each print chip is in fluid communication with outlets (e.g., bottoms of slots 59) in the laminated stack to receive ink from each of the ink ducts.
    • Dependent Claims 2-4: Petitioner argued Silverbrook anticipates the dependent claims by disclosing their additional limitations. For claim 2, Silverbrook was shown to teach that the plurality of layers have ink slots (57, 59) and ink holes (53) for distributing ink. For claim 3, Silverbrook’s ink ducts (40) were described as extending longitudinally across the pagewidth of the printhead array. For claim 4, Silverbrook was argued to disclose that the entire printhead assembly (11) is supported by a chassis (10) fabricated from pressed steel or aluminum, which constitutes a "metal chassis."

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." Petitioner argued this construction is supported by the specification's description of "laminated layers" being "glued or otherwise bonded together" and is consistent with dictionary definitions. This construction was presented as narrower than an overly broad construction proposed by the Patent Owner in co-pending litigation, which Petitioner contended would improperly encompass non-laminated structures joined by other means like screws.
• "transitional ducts": Petitioner proposed this term be construed as "channels for carrying ink from one structure to an adjoining structure." This construction was based on the specification's disclosure of ink traveling from the ink distribution molding to the laminated stack via transitional ducts (51) that bridge the two separate components.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-4 of the ’550 patent as unpatentable under 35 U.S.C. § 102(b).