DCT

1:20-cv-00187

Slingshot Printing LLC v. HP Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 6:19-cv-00549, W.D. Tex., 09/20/2019
  • Venue Allegations: Plaintiff alleges venue is proper in the Western District of Texas because Defendant HP Inc. maintains a significant and continuous physical presence, including a corporate office and data centers in Austin, employs Texas residents, and conducts substantial business in the district through direct sales and an extensive network of resellers participating in its "HP Partners First Program."
  • Core Dispute: Plaintiff alleges that Defendant’s inkjet printers, printheads, and ink cartridges infringe a portfolio of ten U.S. patents related to the design, construction, and operation of thermal inkjet printhead components.
  • Technical Context: The patents concern the micro-scale engineering of thermal inkjet printheads, focusing on optimizing the physical dimensions and power delivery parameters of heating elements to enhance reliability and print quality.
  • Key Procedural History: The patents-in-suit originated with Lexmark International, Inc., were acquired by Funai Electric Co., Ltd. in 2013, and subsequently assigned to Plaintiff Slingshot Printing LLC. The complaint alleges Defendant had notice of U.S. Patent No. 6,213,587 at least as early as June 11, 2019, due to a prior lawsuit, a fact which may be relevant to allegations of willful infringement for that patent.

Case Timeline

Date Event
1999-07-19 U.S. Patent No. 6,213,587 Priority Date
2001-04-10 U.S. Patent No. 6,213,587 Issued
2002-05-14 U.S. Patent No. 7,410,246 Priority Date
2002-08-05 U.S. Patent No. 6,575,563 Priority Date
2002-11-20 U.S. Patent No. 6,676,246 Priority Date
2002-12-17 U.S. Patent No. 6,786,575 Priority Date
2003-06-10 U.S. Patent No. 6,575,563 Issued
2003-11-14 U.S. Patent No. 7,018,012 Priority Date
2004-01-13 U.S. Patent No. 6,676,246 Issued
2004-09-07 U.S. Patent No. 6,786,575 Issued
2004-09-30 U.S. Patent No. 7,195,341 Priority Date
2005-09-29 U.S. Patent No. 7,559,629 Priority Date
2005-09-30 U.S. Patent No. 7,290,864 Priority Date
2005-12-30 U.S. Patent No. 7,484,823 Priority Date
2006-03-28 U.S. Patent No. 7,018,012 Issued
2007-03-27 U.S. Patent No. 7,195,341 Issued
2007-11-06 U.S. Patent No. 7,290,864 Issued
2008-08-12 U.S. Patent No. 7,410,246 Issued
2009-02-03 U.S. Patent No. 7,484,823 Issued
2009-07-14 U.S. Patent No. 7,559,629 Issued
2019-06-11 Alleged Notice of ’587 Patent via Prior Lawsuit
2019-09-20 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 6,213,587 - “Ink jet printhead having improved reliability,” issued April 10, 2001

The Invention Explained

  • Problem Addressed: The patent’s background section identifies a need to improve the reliability of inkjet printheads, which is directly linked to the operational lifespan of the energy-generating transducers, or heaters, that eject ink droplets (’587 Patent, col. 1:40-47).
  • The Patented Solution: The invention proposes that transducer life can be increased by controlling specific physical and operational parameters. The solution involves an inkjet printhead with a nozzle plate of a specific thickness (less than 62 microns) and a transducer that operates below a specific power density (less than 2.159 GW/m²) to reduce stress and wear on the components (’587 Patent, Abstract; col. 2:46-51).
  • Technical Importance: This approach provided a method to engineer more durable and reliable printheads, a critical factor for market competitiveness and consumer satisfaction in the inkjet printer industry (Compl. ¶ 33).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 29.
  • Essential elements of independent claim 1 include:
    • A transducer arranged within a chamber.
    • A plate with an aperture that cooperates with the chamber for ink ejection.
    • The plate has a thickness of less than 62 microns.
    • The transducer is capable of being energized with a power density less than 2.159 GW/m².
  • The complaint reserves the right to assert dependent claims (Compl. ¶ 73).

U.S. Patent No. 6,575,563 - “Power/volume regime for ink jet printers,” issued June 10, 2003

The Invention Explained

  • Problem Addressed: To achieve high-quality printing, it is imperative to maintain a stable and predictable velocity for ejected ink droplets, as inconsistencies can lead to misaligned dots on the print medium (’563 Patent, col. 1:12-29).
  • The Patented Solution: The invention establishes a specific "power/volume regime" to ensure stable droplet velocity. It defines a "heating element volume" as the heater resistor's surface area multiplied by the combined thickness of the resistor and its adjacent protective layer. The solution claims that providing a power density of at least 1.5×10¹⁵ watts per cubic meter within this defined volume accomplishes the goal of stable ink ejection (’563 Patent, Abstract; col. 2:24-35).
  • Technical Importance: This patent introduced a precise volumetric power density parameter for designing and operating heater elements, enabling more consistent performance critical for high-resolution printing (Compl. ¶ 37).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 11.
  • Essential elements of independent claim 1 include:
    • An inkjet print head with a heater chip comprising a plurality of heating elements.
    • Each heating element comprises a heater resistor (with an area and thickness) and an adjacent protective layer (with a thickness).
    • A "heating element volume" is defined as the resistor area multiplied by the sum of the resistor and protective layer thicknesses.
    • Each heating element is operable to provide a predetermined minimum power density per unit volume within that heating element volume.
    • A power supply provides the minimum power level to the heater resistors.
  • The complaint reserves the right to assert dependent claims (Compl. ¶ 100).

U.S. Patent No. 6,676,246 - “Heater construction for minimum pulse time,” issued January 13, 2004

  • Technology Synopsis: This patent addresses the need for faster printhead operation by disclosing a heater chip structure that achieves stable ink ejection with a very short energy pulse time (less than 0.73 microseconds). This is accomplished by operating within a specific energy per unit volume range (2.9 to 4.0 GJ/m³) and using one or more protective layers with a total thickness of less than 7200 angstroms (Compl. ¶ 41; ’246A Patent, col. 2:46-55).
  • Asserted Claims: 1, 4, 5, 6, 8, and 11 are asserted (Compl. ¶ 131).
  • Accused Features: The complaint alleges that the HP 831 printhead's heater resistor, protective layers, and operational parameters meet the claimed energy, pulse time, and thickness limitations (Compl. ¶¶ 143-147).

U.S. Patent No. 6,786,575 - “Ink jet heater chip and method therefor,” issued September 7, 2004

  • Technology Synopsis: This patent describes a specific multi-layer construction for an inkjet heater chip to improve thermal efficiency. The invention details a sequence of layers—a first metal resistive layer, a second metal conductive layer, a passivation layer, a cavitation layer, and a dielectric layer—and specifies that their thicknesses are defined by separate deposition and etching processes to enable independent control over thermal and electrical properties (’575 Patent, Abstract).
  • Asserted Claims: 1, 4, and 6 are asserted (Compl. ¶ 157).
  • Accused Features: The infringement allegations focus on the layered construction of the heater chip within the HP 75XL ink cartridge, mapping the accused product's structure to the claimed layers (Compl. ¶¶ 161-167).

U.S. Patent No. 7,018,012 - “Microfluid ejection device having efficient logic and driver circuitry,” issued March 28, 2006

  • Technology Synopsis: This invention aims to reduce the substrate area required for printhead circuitry. It discloses a semiconductor substrate where the driver transistors for the fluid ejection actuators have a specific active area (from about 1000 to less than 15,000 µm²) and are driven by logic circuits composed of a high-density array of MOS transistors with small gate lengths (’012 Patent, Abstract).
  • Asserted Claims: 1, 2, 5, 6, and 11 are asserted (Compl. ¶ 178).
  • Accused Features: The complaint accuses the semiconductor substrate of the HP 64XL ink cartridge, alleging its driver transistors and logic circuits have the size and construction claimed in the patent (Compl. ¶¶ 184-190).

U.S. Patent No. 7,195,341 - “Power and ground buss layout for reduced substrate size,” issued March 27, 2007

  • Technology Synopsis: This patent discloses a space-saving layout for a semiconductor substrate in a micro-fluid ejection device. The layout arranges ejection actuators, power transistors, and logic circuits in adjacent columnar arrays. To reduce the substrate footprint, power and ground conductors are routed in a second metal layer that physically overlaps the active areas of the power transistors and logic circuits, respectively (’341 Patent, Abstract).
  • Asserted Claims: 1, 2, 3, and 8 are asserted (Compl. ¶ 201).
  • Accused Features: The allegations target the substrate layout of the HP 64XL cartridge, claiming its power and ground conductors are routed over the top of the transistor and logic circuit areas as described in the patent (Compl. ¶¶ 210-211).

U.S. Patent No. 7,290,864 - “Heater chips with a reduced number of bondpads,” issued November 6, 2007

  • Technology Synopsis: This invention seeks to reduce the chip area consumed by electrical connection points (bondpads). It describes a heater chip where a single bondpad supplies power to at least a portion of a first heater array and at least a portion of a second heater array, which are often located on opposite sides of an ink via, through one or more power traces (’864 Patent, Abstract).
  • Asserted Claims: 1, 3, 5, and 6 are asserted (Compl. ¶ 224).
  • Accused Features: The complaint accuses the heater chip in the HP 64XL cartridge, alleging that it uses a single bondpad to supply power to two distinct heater arrays located on either side of an ink via (Compl. ¶¶ 231-234).

U.S. Patent No. 7,410,246 - “Heater chip configuration for an inkjet printhead and printer,” issued August 12, 2008

  • Technology Synopsis: This patent claims a heater chip with specific dimensional constraints to optimize performance. The asserted claim requires a heater with an area (length multiplied by width) of less than 400 micrometers squared and a heater thickness (defined by the resistor and overcoat layers) between about 500 and 6000 angstroms (’246B Patent, Abstract; Claim 24).
  • Asserted Claims: Claim 24 is asserted (Compl. ¶ 245).
  • Accused Features: The allegations focus on the measured dimensions of the heater elements in the HP 64XL cartridge's heater chip, contending they fall within the claimed ranges (Compl. ¶¶ 258-259).

U.S. Patent No. 7,484,823 - “Methods and apparatuses for regulating the temperature of multi-via heater chips,” issued February 3, 2009

  • Technology Synopsis: This patent addresses thermal management in printheads with multiple ink vias. It discloses a heater chip with a temperature sensing element positioned in the region between a first heater array and a second heater array. This sensor's reading is used to regulate heating applied to those arrays, controlling the local temperature (’823 Patent, Abstract).
  • Asserted Claims: 1, 2, 5-9, 11, 12, and 15-17 are asserted (Compl. ¶ 269).
  • Accused Features: The complaint accuses the heater chip in the HP OfficeJet Pro 6978 printer of infringing by positioning temperature sensors between adjacent heater arrays to regulate their temperature (Compl. ¶¶ 275-277).

U.S. Patent No. 7,559,629 - “Methods and apparatuses for implementing multi-via heater chips,” issued July 14, 2009

  • Technology Synopsis: This invention discloses a space-efficient layout for controlling multiple heater arrays. It describes a chip where at least one logic array, comprising first and second sets of logic cells, is disposed physically between a first heater array and a second heater array. This arrangement allows the single logic array to control both adjacent heater arrays simultaneously (’629 Patent, Abstract).
  • Asserted Claims: 1-4, 8, 9, and 14 are asserted (Compl. ¶ 299).
  • Accused Features: The allegations target the heater chip of the HP OfficeJet Pro 6978, claiming it infringes by placing a logic array between two heater arrays to control their operation (Compl. ¶ 303).

III. The Accused Instrumentality

Product Identification

  • The complaint accuses a wide range of HP products across its ten counts, including HP Latex series printers, HP OfficeJet and DeskJet printers, HP ENVY photo printers, and their corresponding inkjet printheads (e.g., HP 831) and ink cartridges (e.g., HP 75XL, HP 64XL) (Compl. ¶¶ 73, 100, 131, 157, 178, 201, 224, 245, 269, 299).

Functionality and Market Context

  • The accused products are thermal inkjet printing systems where printheads or integrated cartridges eject ink droplets by rapidly heating ink with resistive elements. The complaint provides detailed technical analysis of specific product exemplars, including the HP 831 printhead and HP 64XL and 75XL cartridges, using annotated micrographs to illustrate the allegedly infringing components like transducers, firing chambers, nozzle plates, and layered semiconductor substrates (Compl. ¶¶ 77, 161, 184). For example, a micrograph of the HP 831 printhead identifies the location of the "Transducer" within the printhead structure (Compl. p. 18). The complaint alleges these products are sold nationwide through HP's website, major retailers, and a formal "HP Partners First Program" with resellers located in the judicial district (Compl. ¶¶ 14, 21-22).

IV. Analysis of Infringement Allegations

6,213,587 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a) a transducer, at least a portion of which is arranged within a chamber The accused HP 831 printhead contains a resistive heater transducer, a portion of which is arranged within a firing chamber. ¶77 col. 5:16-21
b) a plate provided with at least one aperture capable of cooperating with the chamber to allow ink to be ejected from the chamber The HP 831 has a nozzle plate with apertures (nozzles) that work with the firing chamber to eject ink. ¶78 col. 6:35-39
wherein the plate has a thickness of less than 62 microns The nozzle plate of the HP 831 allegedly has a thickness of approximately 13.4 microns. ¶79 col. 2:48-49
and the transducer is capable of being selectively energized with a power density less than 2.159 GW/m² to cause droplets of ink to be ejected from the chamber On information and belief, the transducer in the HP 831 is capable of being energized with a power density below this claimed threshold. ¶80 col. 2:49-51

6,575,563 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a heater resistor having a heater resistor area and a heater resistor thickness The HP 831 printhead's heater resistor allegedly has an area of approximately 622 µm² and a thickness of 98.8 nm. ¶111, ¶112 col. 2:20-22
and a protective layer adjacent the heater resistor having a protective layer thickness The HP 831 has an adjacent protective layer made of SiN and SiC with a combined thickness derived from its constituent layers. ¶114 col. 2:22-23
where the heater resistor area multiplied by a sum of the heater resistor thickness and the protective layer thickness represents a heating element volume The complaint calculates the heating element volume by multiplying the alleged heater area by the sum of the alleged resistor and protective layer thicknesses. ¶115 col. 2:24-27
where each heating element is operable to provide a predetermined minimum power density per unit volume within the heating element volume... On information and belief, the HP 831's power supply provides a power level sufficient to generate a power density per unit volume greater than 1.5×10¹⁵ watts per cubic meter. ¶118 col. 2:28-32

Identified Points of Contention

  • Scope Questions: Many allegations concerning specific numerical values (e.g., power density, thickness, volumetric power density) are made "on information and belief." A central point of contention will be whether Plaintiff can produce sufficient factual evidence from testing and reverse engineering to prove that the accused products meet these precise quantitative limitations as defined in the patents.
  • Technical Questions: For the ’587 Patent, a key question is what evidence supports the allegation that the accused transducer is "capable" of operating below the claimed power density, as infringement may not require it to always operate in that mode. For the ’563 Patent, the dispute may focus on the calculation of the "heating element volume," specifically which layers of the accused device constitute the "protective layer" for the purposes of the claim's explicit formula. An annotated micrograph shows the circuitry and heating element sectioned for analysis (Compl. p. 28).

V. Key Claim Terms for Construction

Term: "power density" (from ’587 Patent)

  • Context and Importance: This quantitative limitation is central to the infringement theory for the '587 patent. The method of calculating and measuring this value will be critical. Practitioners may focus on this term because the patent's specification details its calculation based on specific test conditions, which could be argued to limit its scope.
  • Evidence for a Broader Interpretation: The claims themselves do not specify a measurement methodology, which could support using any method accepted by a person of ordinary skill in the art at the time of the invention (’587 Patent, col. 17:20-25).
  • Evidence for a Narrower Interpretation: The patent's detailed description and examples provide specific calculations and contour plots (e.g., FIG. 14) showing how power density relates to other variables under test conditions (’587 Patent, col. 7:51-61). A defendant may argue these examples implicitly define and constrain the term's meaning.

Term: "heating element volume" (from ’563 Patent)

  • Context and Importance: The infringement allegation for the '563 patent hinges on a calculation of "power density per unit volume," making the definition of this volume critical. The dispute will likely be less about the term's legal definition and more about its factual application to the accused device's physical structure.
  • Evidence for a Broader Interpretation: Claim 1 provides an explicit definition: "the heater resistor area multiplied by a sum of the heater resistor thickness and the protective layer thickness" (’563 Patent, col. 12:29-32). Plaintiff will likely argue this definition should be applied directly to the physical layers of the accused device, which the complaint alleges includes a multi-layer protective structure (Compl. ¶ 114).
  • Evidence for a Narrower Interpretation: A defendant could argue that not all layers adjacent to the heater resistor in its product serve a "protective" function as contemplated by the patent. The specification distinguishes between passivation and cavitation layers, suggesting a potential basis to argue certain layers should be excluded from the "protective layer thickness" used in the volume calculation (’563 Patent, col. 4:35-49).

VI. Other Allegations

Indirect Infringement

  • For all ten patents, the complaint alleges induced infringement. The factual basis is that Defendant HP provides user guides, manuals, advertisements, and website support that instruct and encourage customers and resellers to set up, use, and sell the accused inkjet printers and cartridges in their intended, infringing manner (Compl. ¶¶ 92, 123, 150).

Willful Infringement

  • For the ’587 patent, the complaint alleges pre-suit knowledge of infringement based on a prior lawsuit filed against HP on June 11, 2019, involving the same patent (Compl. ¶ 91). For the remaining nine patents, the complaint asserts that HP has had knowledge at least since the filing of the current action, forming a basis for post-suit willfulness (Compl. ¶¶ 122, 148, 169).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A central issue will be one of evidentiary proof: can the Plaintiff, through reverse engineering and expert testing, produce sufficient evidence to demonstrate that HP's numerous accused products meet the specific, quantitative limitations recited in the claims across a ten-patent portfolio, particularly for the many allegations made "on information and belief"?
  • A key legal question will be one of definitional scope: for the '563 patent and others that rely on it, will the patent’s explicit definition of "heating element volume" be interpreted to unambiguously include all adjacent layers as "protective," or is there room for a narrower construction that excludes certain layers in HP's multi-layer chip designs from the infringement calculation?
  • A critical question for damages will be the impact of pre-suit notice for the '587 patent. The court will need to determine if HP's alleged infringement after being served in a prior lawsuit for the same patent constitutes objective recklessness, which could support a finding of willfulness and potential for enhanced damages on that count.