HP Inc v. Memjet Technology Ltd

1. Case Identification

• Case #: IPR2016-00746
• Patent #: 6,575,549
• Filed: March 11, 2016
• Petitioner(s): HP Inc.
• Patent Owner(s): Memjet Technology Limited
• Challenged Claims: 1-16, 19-20

2. Patent Overview

• Title: Inkjet Printhead with Fault Tolerance
• Brief Description: The ’549 patent is directed to a printer and method for modifying a digital image to compensate for the failure of one or more ink jet nozzles. The technology identifies a failed nozzle and shifts the ink dot originally intended for that location to an alternative location to be printed by an adjacent, functioning nozzle.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-4, 6-12, 16, and 19 by Adler

• Prior Art Relied Upon: Adler (WO 97/31781).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Adler discloses every limitation of the challenged claims. Adler teaches a method for compensating for unprinted ink dot lines caused by a defective ink jet head by manipulating adjacent printed lines. Specifically, Adler discloses identifying the defective nozzle locations using an ink jet head test module and shifting the printed position of the ink to an alternative location using operative adjacent nozzles to restore the intended dot percentage. Petitioner asserted that Adler's teachings also meet dependent claim limitations, such as shifting ink "transversely" (claim 2), having shifted locations be "immediately adjacent" (claim 8), printing "oversize drops of ink" (claim 9), and printing "extra drops of ink" (claim 10). For apparatus claim 11, Adler was argued to disclose a printer with a row of devices (print head arrays), means to move the substrate (a rotatable drum and controller), means to determine non-operating devices (a test module with a camera), and control means (an ink jet printer controller) to shift the dot position to adjacent nozzles.

Ground 2: Anticipation of Claim 5 by JPH10-006488

• Prior Art Relied Upon: JPH10-006488.
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that JPH10-006488 anticipates claim 5, which adds the limitation that when multiple shifted locations are possible, the chosen location is "influenced by the position of any nearby shifted ink or most recently printed shifted ink." JPH10-006488 describes a compensation method where, upon nozzle failure, "complementary dots...are incorporated on both sides thereof in an alternating manner on the left and right." Petitioner argued this explicit teaching of alternating the placement of replacement dots between the left and right sides of the failed nozzle line directly discloses that the choice for the current replacement dot's location is influenced by the location of the most recent one (i.e., if the last dot was placed on the left, the next is placed on the right). This directly meets the "influenced by" limitation of claim 5.

Ground 3: Anticipation of Claims 15 and 20 by McClellan

• Prior Art Relied Upon: McClellan (Patent 6,439,681).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that McClellan anticipates claims 15 and 20, which depend from apparatus claim 11. Claim 15 requires the control means to activate devices "immediately adjacent" the failed device. McClellan teaches compensating for a failed printing element by increasing output from printing elements that are "adjacent to a failed printing element" and preferably "closest to the failed element." Claim 20 requires that the selected adjacent device be activated at a "higher frequency." McClellan explicitly discloses that adjacent ink-energizing elements can be fired at an "increased rate" or "increased frequency" to deposit additional ink to compensate for the failure. Petitioner asserted these teachings directly map to the limitations of claims 15 and 20.

• Additional Grounds: Petitioner asserted that claims 12-14 are obvious over Adler. The argument was that even if Adler does not explicitly disclose the specific logic for choosing among available adjacent nozzles, a POSITA would find it obvious to implement a simple, predictable sequence (e.g., check same-row nozzles first, then other-row nozzles) to optimize print quality by placing the replacement dot at the closest possible location.

4. Key Claim Construction Positions

• "longitudinally" & "transversely": Petitioner proposed these terms be construed as "parallel to the defective or blank line caused by the failed nozzle" and "perpendicular to the defective or blank line caused by the failed nozzle," respectively. This construction was argued to be broader and more consistent with the patent's disclosure than a narrower definition (e.g., paper feed direction) proposed by the patentee during European prosecution.
• Means-Plus-Function Terms (Claims 11-20): Petitioner argued that several "means" limitations are means-plus-function elements for which the specification fails to disclose adequate corresponding structure, rendering them indefinite. However, for the purposes of the IPR, Petitioner proposed broad constructions:
  • "means to move the substrate": The corresponding structure is "any suitable structure to cause the substrate to move relative to a printhead."
  • "means to determine if one or more of said devices is not operating correctly": The corresponding structure is "a diagnostic system or equivalents thereto."
  • "control means": The corresponding structure is "a control system or equivalents thereto." Petitioner argued these terms in the specification are generic and merely recite the claimed function.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-16 and 19-20 of the ’549 patent as unpatentable under 35 U.S.C. §§ 102 and 103.