Canon USA Inc v. Slingshot Printing LLC

1. Case Identification

• Case #: IPR2022-01414
• Patent #: 7,195,341
• Filed: August 23, 2022
• Petitioner(s): Canon U.S.A., Inc., and Canon Inc.
• Patent Owner(s): Slingshot Printing LLC
• Challenged Claims: 1-5 and 8

2. Patent Overview

• Title: Semiconductor Substrate for Micro-Fluid Ejection Device
• Brief Description: The ’341 patent discloses a specific layout for a semiconductor substrate used in micro-fluid ejection devices, such as inkjet printers. The invention aims to provide improved conductor layouts that reduce substrate size while accommodating increased functionality by arranging actuators, power transistors, and logic circuits in adjacent columnar arrays and routing power and ground busses in a second metal layer to overlap the active circuit areas.

3. Grounds for Unpatentability

Ground 1: Claims 1-5 and 8 are obvious over Torgerson in view of Bruce.

• Prior Art Relied Upon: Torgerson (Patent 6,412,917) and Bruce (Patent 7,240,997).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Torgerson, which describes an inkjet printhead substrate with a nearly identical layout, discloses every limitation of claim 1 except for the final element: a ground conductor routed in a second metal layer that overlaps the logic circuit area. Torgerson teaches a ground bus but does not place it in the second metal layer overlapping the logic. Petitioner contended that Bruce remedies this deficiency by explicitly teaching a fluid ejection device with a second metal layer where a ground conductor is routed to overlie the logic portions, precisely as claimed. Dependent claims 2-5 and 8 were argued to be obvious as they recite features also taught by Torgerson, such as using heater resistors for actuators (claim 2) and comprising FETs as power transistors (claim 4).
  • Motivation to Combine: Petitioner asserted a person of ordinary skill in the art (POSITA) would combine Torgerson and Bruce because both are analogous art addressing the same problem of reducing substrate size in inkjet printheads. A POSITA seeking to make Torgerson’s design more compact would have looked to known space-saving techniques, such as the one taught by Bruce. Bruce explicitly states that placing the ground conductor in the second metal layer over the logic area "avoids costs associated with increased die sizes." Therefore, incorporating Bruce’s ground conductor layout into Torgerson’s otherwise similar design was presented as a predictable design choice.
  • Expectation of Success: A POSITA would have had a high expectation of success because the combination involved applying a known layout technique (from Bruce) to a well-understood substrate architecture (from Torgerson) to achieve the predictable result of a smaller die size.

Ground 2: Claims 1-5 and 8 are obvious over Furukawa in view of Torgerson.

• Prior Art Relied Upon: Furukawa (Japanese Application No. 1996-108536) and Torgerson (Patent 6,412,917).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Furukawa discloses a miniaturized recording head with many core features of claim 1, including a layout with adjacent power transistors and logic circuits, and routing both a power supply line and a ground line in a second metal layer to overlap the power transistor and logic circuit areas, respectively. However, Furukawa allegedly fails to explicitly teach (i) a fluid supply slot adjacent to the ejection actuators and (ii) connecting the logic circuits to the power transistors via a polysilicon conductor layer. Petitioner asserted that Torgerson supplies these missing elements. Torgerson explicitly teaches a printhead substrate with three ink feed slots adjacent to columnar arrays of heater actuators and discloses connecting FET power transistors to decoder logic circuits using polysilicon gate fingers.
  • Motivation to Combine: The motivation to combine was based on improving Furukawa’s design with well-known and advantageous features from Torgerson. Both references are in the same field and address the goal of miniaturization. A POSITA would have recognized that Furukawa’s recording head, to be functional in an inkjet printer, would require a method for ink supply; Torgerson’s use of ink feed slots was argued to be a known and obvious solution. Furthermore, a POSITA would have been motivated to replace the power transistors in Furukawa with Torgerson’s FETs, which offer better performance without increasing substrate size, and connect them using Torgerson’s taught polysilicon layer, a standard practice when using FETs.
  • Expectation of Success: A POSITA would have reasonably expected success in incorporating Torgerson's conventional ink supply slots and standard FET-based control circuitry into Furukawa’s layout to create a more functional and efficient compact printhead.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not exercise its discretion to deny institution under §314(a) based on the Fintiv factors. The petition asserted that the parallel district court proceeding was in its earliest stages, with no trial date set and key deadlines, such as for claim construction, falling well after the Board's deadline for a Final Written Decision (FWD). Petitioner contended that because the FWD would issue long before any potential trial, institution would conserve both judicial and party resources. The petition also highlighted that the invalidity challenges were compelling and relied on prior art that the patent examiner had not previously considered during prosecution.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-5 and 8 of Patent 7,195,341 as unpatentable under 35 U.S.C. §103.