PTAB

IPR2016-00913

HP Inc v. Memjet Technology Ltd

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Printhead Assembly
  • Brief Description: The ’986 patent relates to a drop-on-demand printhead assembly, suitable for pagewidth printing, that utilizes an ink distribution assembly to supply ink from multiple sources to multiple printhead modules. The core of the distribution assembly is a "laminated stack of ink distribution sheets" with precisely formed holes and slots that create pathways for ink to travel to the printhead chips.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, and 6 are obvious over Boyd, Waller, Silverbrook, and Kubota.

  • Prior Art Relied Upon: Boyd (Patent 6,322,206), Waller (Patent 6,250,738), Silverbrook (WO 99/03681), and Kubota (Japanese Publication No. 09-187939).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of Boyd and Waller disclosed the primary elements of claim 1, including a printhead assembly with a laminated stack, an ink distribution molding, and a network of slots and apertures for fluid communication. Boyd, in particular, was argued to teach a multi-layered substrate with laminated layers that distribute ink, as well as slots and apertures of different shapes. To meet the limitation of “micro-electromechanical printheads,” Petitioner relied on Silverbrook, which discloses using thermoelastic bend actuators (a type of micro-electromechanical system) for ink ejection. To meet the limitation of sheets having "fewer and fewer said apertures" in sequence, Petitioner pointed to Kubota, which discloses a multi-layered stack where the number of ink passages decreases from four to one across successive layers. For claim 2, Boyd was argued to disclose the required "printhead driver circuitry" in the form of an integrated circuit or electronic controller. For claim 6, Waller was argued to teach an ink distribution molding with "elongate channels."
    • Motivation to Combine: A POSITA would combine the related teachings of Boyd and Waller to improve ink distribution in pagewidth printers. A POSITA would have been motivated to replace the thermal printheads of Boyd/Waller with the micro-electromechanical printheads of Silverbrook to achieve known benefits such as reduced cost and lower power consumption. Finally, a POSITA would incorporate Kubota's design of decreasing apertures as it represented a predictable and obvious solution for routing multiple fluids through a layered structure to their respective distribution points.

Ground 2: Claim 3 is obvious over Boyd, Waller, Silverbrook, Kubota, and Toganoh.

  • Prior Art Relied Upon: Boyd (Patent 6,322,206), Waller (Patent 6,250,738), Silverbrook (WO 99/03681), Kubota (Japanese Publication No. 09-187939), and Toganoh (Patent 4,559,543).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground adds Toganoh to the combination from Ground 1 to address the additional limitation in claim 3, which requires that the "printhead driver circuitry is mounted to a printed circuit board." While Petitioner argued Boyd's integrated circuit was equivalent to a printed circuit board (PCB), Toganoh was introduced as explicitly disclosing a "wiring plate" (the claimed PCB) with a "drive controlling portion" and a "multi-layer wiring plate" (the claimed driver circuitry).
    • Motivation to Combine: A POSITA would have been motivated to mount the integrated circuit driver of Boyd onto the wiring plate of Toganoh. The primary motivation asserted was to replaceably secure the integrated circuit, as Toganoh teaches that its components are constituted separately and are readily exchangeable. This modification would improve the serviceability and modularity of the printhead assembly.

Ground 3: Claims 7-9 are obvious over Boyd, Waller, Silverbrook, Kubota, and Miura.

  • Prior Art Relied Upon: Boyd (Patent 6,322,206), Waller (Patent 6,250,738), Silverbrook (WO 99/03681), Kubota (Japanese Publication No. 09-187939), and Miura (Patent 4,555,717).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground adds Miura to the combination from Ground 1 to address limitations in claims 7-9 concerning the elongate channels. Claim 7 requires that at least one channel includes an "air inlet port" while others comprise "printing fluid channels." Boyd and Waller were asserted to teach the fluid channels. Miura was introduced to teach the air inlet port, as it discloses an inkjet printhead with a laminar airflow chamber connected to a pressurized air source. Claim 8’s requirement for parallel channels and Claim 9’s requirement for a cover molding with ports were argued to be met by the base combination of Boyd and Waller.
    • Motivation to Combine: A POSITA would combine Miura's air inlet port with the printhead design of Boyd/Waller to solve the known problem of nozzle clogging. The motivation was to create a positive air pressure at the nozzle location to prevent particulates or ink mist from accumulating, which would predictably result in improved drop formation stability and overall printhead reliability.

4. Key Claim Construction Positions

  • Petitioner proposed a construction for the key term “laminated stack of ink distribution sheets” that was central to its invalidity arguments.
  • Proposed Construction: "an ink distribution structure manufactured by layering thin, flat sheets one on top of the other and gluing or otherwise bonding them together."
  • Significance: This construction was argued to be supported by the patent’s specification and dictionary definitions. It was critical for Petitioner’s case because it allowed the multi-layered, bonded substrates of the prior art (e.g., Boyd and Kubota) to be mapped directly onto this claim limitation, which Petitioner contended was the broadest reasonable interpretation of the term.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-3 and 6-9 of the ’986 patent as unpatentable under 35 U.S.C. §103.