DCT

1:20-cv-00184

Slingshot Printing LLC v. HP Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 6:19-cv-00362, W.D. Tex., 09/20/2019
  • Venue Allegations: Plaintiff alleges venue is proper in the Western District of Texas because HP Inc maintains a regular and established place of business in Austin, Texas, including a corporate office, data centers, and the employment of numerous specialized engineers and other key personnel.
  • Core Dispute: Plaintiff alleges that Defendant’s inkjet printers, printheads, and ink cartridges infringe five patents related to systems for ink supply, pressure regulation, and gas purging within printer cartridges.
  • Technical Context: The technology concerns the fluid mechanics of managing and delivering ink from a replaceable cartridge to a printhead, a fundamental function in the highly competitive consumer and commercial inkjet printer market.
  • Key Procedural History: The patents-in-suit originated with Lexmark International, Inc., were acquired by Funai Electric Co., Ltd. in 2013 as part of a larger technology and asset purchase, and were subsequently assigned to Plaintiff Slingshot Printing LLC. The complaint also notes that Defendant HP has previously litigated other patent cases in the Western District of Texas without contesting jurisdiction or venue.

Case Timeline

Date Event
1991-01-01 Lexmark formed from IBM divestiture
2000-03-09 U.S. Patent No. 6,243,115 Priority Date
2001-05-30 U.S. Patent No. 6,394,593 Priority Date
2001-06-05 U.S. Patent No. 6,243,115 Issues
2002-05-28 U.S. Patent No. 6,394,593 Issues
2003-06-18 U.S. Patent No. 6,817,707 Priority Date
2004-11-16 U.S. Patent No. 6,817,707 Issues
2004-12-01 U.S. Patent No. 7,438,397 Priority Date
2007-06-13 U.S. Patent No. 7,938,523 Priority Date
2008-10-21 U.S. Patent No. 7,438,397 Issues
2011-05-10 U.S. Patent No. 7,938,523 Issues
2013-04-01 Funai Electric Co., Ltd. acquires Lexmark's inkjet technology
2019-09-20 Complaint Filing Date

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

U.S. Patent No. 6,243,115 - “Pressurized ink supply and delivery system for an ink jet printer”

Issued June 5, 2001

The Invention Explained

  • Problem Addressed: The patent addresses the limitations of conventional inkjet printers. Systems with ink supplies on the moving printhead carriage have small capacities, requiring frequent and costly replacement. Systems with larger, stationary ink tanks require a reliable method to transport ink to the printhead, and existing pressure-based systems were often complex, expensive, or orientation-dependent (’115 Patent, col. 1:9-44).
  • The Patented Solution: The invention proposes a system that uses an air pump to create positive pressure within the main interior of a printer cartridge. This pressure acts upon a resilient ink container (e.g., a flexible bag) inside the cartridge, squeezing it and forcing ink to flow out of an outlet towards the printhead. This creates an on-demand, pressurized delivery system that can support larger ink volumes (’115 Patent, Abstract; Fig. 1).
  • Technical Importance: This approach enabled the use of larger, more economical ink supplies by providing a simple and robust mechanism for delivering ink from a stationary source to a moving printhead, addressing key market demands for lower cost-per-page and longer user intervention intervals (’115 Patent, col. 1:13-19).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶53).
  • Essential elements of claim 1 include:
    • A printer cartridge with an interior, an air inlet, and an ink outlet.
    • An air pump connected to the air inlet to create positive pressure in the interior.
    • An ink source within the interior.
    • A resilient air container within the interior, in fluid communication with the air inlet, that expands from the positive pressure to force ink from the ink source through the ink outlet.
  • The complaint reserves the right to assert other claims, including dependent claims 3, 5, and 6 (Compl. ¶53).

U.S. Patent No. 6,394,593 - “Vent system for ink jet pen having internal pressure regulator”

Issued May 28, 2002

The Invention Explained

  • Problem Addressed: Inkjet cartridges often use an internal pressure regulator (described as a "lung") to maintain a slight vacuum, or "backpressure," on the ink supply. These regulators are often made of materials permeable to water vapor. As air enters the regulator from the outside to compensate for used ink, its potentially lower humidity can cause water to evaporate from the ink, altering its properties and degrading print quality and head longevity (’593 Patent, col. 1:19-44).
  • The Patented Solution: The patent discloses a specialized vent that provides air communication but restricts moisture from escaping. This is achieved through an "elongate air flow path," such as a serpentine channel, molded into an exterior surface of the cartridge body. This long, narrow path allows air to slowly enter but "substantially inhibit[s]" water vapor from diffusing out, thereby maintaining a stable, humid environment within the pressure regulator chamber (’593 Patent, Abstract; col. 2:8-17).
  • Technical Importance: By preventing the ink from drying out, the invention helps maintain consistent ink viscosity and print performance over the life of the cartridge, a critical factor for print quality and reliability (’593 Patent, col. 1:50-54).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 12 (Compl. ¶87).
  • Essential elements of claim 1 include:
    • An ink cartridge body with first and second panel portions defining a cavity for ink.
    • A chamber and a "lung type pressure regulator" within the cavity.
    • An "air diffusion path" providing flow communication between the chamber and the atmosphere, comprising an elongate flow path on the body that enables air flow while "substantially inhibiting" water vapor flow out of the chamber.
  • The complaint reserves the right to assert other claims, including dependent claims 2, 3, 5, 6, 12-14, and 16-18 (Compl. ¶87).

U.S. Patent No. 6,817,707 - “Pressure controlled ink jet printhead assembly”

Issued November 16, 2004

  • Technology Synopsis: This patent describes a printhead assembly designed for more efficient manufacturing. It discloses using a first material with a higher melting point for the main ink reservoir and a second, polymeric material with a lower melting point for an internal "pressure control structure." This allows different components to be optimized for their specific functions (e.g., structural rigidity vs. compatibility with a heat-sealed film) and simplifies assembly (’707 Patent, Abstract).
  • Asserted Claims: Claims 1, 5, and 6 are asserted (Compl. ¶136).
  • Accused Features: The complaint accuses the HP 831 Printhead and associated printers, alleging the printhead's body and internal pressure control structure are made of different materials with different melting points (Compl. ¶¶139, 141, 143).

U.S. Patent No. 7,438,397 - “Methods and devices for purging gases from an ink reservoir”

Issued October 21, 2008

  • Technology Synopsis: This invention addresses the problem of air or other gases accumulating in an ink reservoir, which can block ink flow and cause print failures. It discloses a device and method for purging these gases, typically involving a valve assembly (such as a check valve) that allows trapped gas to be withdrawn from a "gas accumulation area" and expelled from the printhead, thereby increasing its operational longevity (’397 Patent, Abstract).
  • Asserted Claims: Claim 20 is asserted (Compl. ¶158).
  • Accused Features: The complaint accuses the HP T Series printers and their HP 711 printhead assemblies. It alleges these products perform a method of displacing and withdrawing gas from the ink reservoir via a check valve (identified as a metal ball valve) (Compl. ¶¶163, 164, 168).

U.S. Patent No. 7,938,523 - “Fluid supply tank ventilation for a micro-fluid ejection head”

Issued May 10, 2011

  • Technology Synopsis: This patent describes a ventilation system for a removable fluid supply tank (ink cartridge) to prevent problems caused by air trapped during installation. It features an "internal vent conduit" located between the fluid exit port and the cartridge cover. When the cartridge is installed, this conduit allows trapped air to be pushed out through an atmospheric vent on the cover, rather than being forced into the printhead or causing ink to seep out (’523 Patent, Abstract).
  • Asserted Claims: Claims 1-3, 5, and 6 are asserted (Compl. ¶178).
  • Accused Features: The complaint accuses the HP 902 ink cartridge and associated printers, such as the HP OfficeJet Pro 6970. It alleges the HP 902 cartridge contains an internal vent conduit that removes air from near the fluid exit port (Compl. ¶¶183, 185).

III. The Accused Instrumentality

Product Identification

  • The complaint names an extensive list of HP products. The infringement allegations focus on specific examples, including the HP PageWide Pro series printers (e.g., MFP 477dw), HP OfficeJet Pro series printers (e.g., 7740), and their associated ink cartridges, such as the HP 972 and HP 952 families (Compl. ¶¶ 53, 58, 68).

Functionality and Market Context

  • The complaint alleges that the accused HP printers and cartridges operate as a system. The printers, such as the HP PageWide Pro, allegedly contain an "air pump" that connects to an "air inlet" on the installed cartridge (Compl. ¶¶ 60, 70). This pump allegedly creates positive pressure inside the cartridge. This pressure acts on what the complaint identifies as a "resilient air container (air bag)," causing it to expand and force ink out of the cartridge's "ink outlet" to the printhead (Compl. ¶¶ 63, 64, 73, 74). The complaint provides an annotated photograph of an HP 972 cartridge showing the alleged "Resilient air container (air bag)" inside an "Ink cavity" (Compl. ¶63, p. 21). Plaintiff alleges these products are sold through numerous channels in the judicial district, including HP's own website and authorized resellers (Compl. ¶¶ 16-22).

IV. Analysis of Infringement Allegations

'115 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An ink supply and delivery system for a printer cartridge, comprising: a printer cartridge having an interior, at least one air inlet to the interior, and at least one ink outlet from the interior; The accused system includes an HP PageWide Pro printer and an HP 972 ink cartridge. The cartridge is alleged to have an interior, an air inlet, and an ink outlet. An annotated photograph shows the location of the air inlet and ink outlet. ¶58, ¶59 col. 4:30-34
an air pump connected to the air inlet for creating a positive pressure in the interior of the printer cartridge; The HP PageWide Pro printer is alleged to have an air pump that connects to the cartridge's air inlet. The complaint includes a photograph demonstrating that turning on the pump causes bubbles to form when a tube from the pump is submerged in water, which purports to show the creation of positive pressure. ¶60, ¶61 col. 4:35-37
an ink source including ink in the interior of the printer cartridge and in fluid communication with the ink outlet; and The HP 972 cartridge contains an "ink source" (the ink-filled cavity) that is in fluid communication with the ink outlet. ¶62 col. 4:50-54
a resilient air container in the interior of the printer cartridge and in fluid communication with the air inlet, the air container expanding from the positive pressure created by the air pump for forcing the ink from the ink source through the ink outlet. The HP 972 cartridge is alleged to have a "resilient air container (air bag)" inside its interior that is in fluid communication with the air inlet. The complaint alleges this bag expands under pressure from the air pump to force ink out of the ink source. ¶63, ¶64 col. 6:53-61
  • Identified Points of Contention:
    • Technical Question: The complaint's theory relies on the "air bag" expanding to force ink out. A central factual question will be whether the accused air bag functions in this manner, as opposed to another mechanism. The patent describes multiple configurations (e.g., air bag inside, next to, or encapsulating the ink source), and the court will require evidence to determine if the accused product's operation maps onto the specific functions claimed.
    • Scope Question: Does the accused "air bag" meet the claim limitation of a "resilient air container"? While the complaint labels it as such, the construction of this term and its functional requirement of "expanding... for forcing the ink" will be a primary focus. Defendant may argue its structure operates differently or that the term should be limited to the specific embodiments shown in the patent's figures.

'593 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An ink cartridge for an ink jet printer, the cartridge comprising a body portion including a first panel portion having an interior surface opposite an exterior surface exposed to an atmosphere..., a second panel portion attachable to the body portion to define a cavity for containing ink...; The HP 972 cartridge is alleged to have a body portion comprised of a "first panel portion" and an attachable "second panel portion" that together define an "Ink Cavity." Photographs show these components. ¶92, ¶93, ¶94 col. 2:20-25
a chamber defined within the cavity adjacent the interior surface of the first panel portion of the body portion, a lung type pressure regulator disposed within the cavity adjacent the chamber; The HP 972 cartridge is alleged to contain a "chamber (air chamber inside an air bag)" and a "lung type pressure regulator (air bag)" within the ink cavity. ¶95 col. 2:25-28
and an air diffusion path for providing flow communication between the chamber and the atmosphere, the air diffusion path comprising an elongate flow path defined on the first panel portion of the body portion, the flow path having a first end in flow communication with the chamber and a second end located on the exterior surface... The HP 972 is alleged to have an "air diffusion path/flow path" on the exterior of its first panel portion that provides communication between the internal chamber and the atmosphere. An annotated photograph traces this alleged path from an internal aperture to an external terminal portion. ¶96 col. 2:28-35
  • Identified Points of Contention:
    • Scope Question: The claim requires the "air diffusion path" to perform the function of "substantially inhibiting flow of water vapor out of the chamber." The complaint alleges this function is met (Compl. ¶97) and provides a calculated ratio of path length to cross-sectional area as evidence (Compl. ¶100). The central dispute will be whether this physical structure actually performs the claimed function to the required degree, a question that will likely require expert testimony and testing.
    • Technical Question: Is the accused "air bag" (Compl. ¶95), which is part of a system actively pressurized by an air pump per the '115 patent allegations, properly characterized as a "lung type pressure regulator" as understood in the '593 patent, whose background describes regulating a passive vacuum or "backpressure" system? The court will need to determine if there is a fundamental operational mismatch between the patented environment and the accused environment.

V. Key Claim Terms for Construction

U.S. Patent No. 6,243,115

  • The Term: "resilient air container"
  • Context and Importance: This term is the central novel element of claim 1. The infringement case hinges on whether the accused "air bag" in HP's cartridges is properly defined as this element, both structurally and functionally. Practitioners may focus on this term because its construction will determine whether the claim reads on a component that expands under pressure to actively expel ink.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification describes the element functionally, stating that "the air container expand[s] from the positive pressure... for forcing the ink from the ink source through the ink outlet" (e.g., ’115 Patent, col. 6:58-61). This supports a construction focused on the function of expansion-driven ink expulsion, regardless of specific form.
    • Evidence for a Narrower Interpretation: The detailed description and figures disclose several specific embodiments: an air container inside the ink container (Fig. 4), encapsulating the ink container (Fig. 3), or adjacent to it (Fig. 2). A defendant could argue that the term should be construed as limited to one or more of these specific structural relationships, rather than covering any component that expands within the cartridge interior.

U.S. Patent No. 6,394,593

  • The Term: "air diffusion path"
  • Context and Importance: This term defines the invention itself. The dispute will turn on whether the accused channel on the HP cartridge meets the full definition, which includes both structural ("elongate flow path") and functional ("substantially inhibiting flow of water vapor") limitations.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claims and summary describe the invention broadly as an "elongate air flow path defined adjacent the exterior of the pen" (’593 Patent, col. 2:11-12). Plaintiff may argue this suggests any long, narrow channel designed for this purpose would suffice.
    • Evidence for a Narrower Interpretation: The specification repeatedly describes the path as "serpentine" or a "labyrinth" (’593 Patent, col. 5:48-51) and provides specific exemplary ratios of channel length to cross-sectional area (from 20 mm⁻¹ to 6000 mm⁻¹) (’593 Patent, col. 5:56-59). Defendant may argue the term should be limited to paths with these specific geometric or mathematical characteristics.

VI. Other Allegations

  • Indirect Infringement: For all asserted patents, the complaint alleges induced infringement under 35 U.S.C. § 271(b). The factual basis is HP’s alleged actions in "instructing and encouraging customers to use (and resellers to use, sell and offer to sell) HP inkjet printers and ink cartridges through HP’s user guides/manuals, advertisement, promotional materials and instructions" (e.g., Compl. ¶¶ 80, 128). This alleges HP provides the means and intends for its customers to assemble and use the products in an infringing manner.
  • Willful Infringement: The complaint alleges willful infringement for all asserted patents, but the allegations are based on knowledge acquired after the lawsuit was filed. The complaint states, "On information and belief, at least since its post-filing knowledge of the '[patent number]' patent, HP knowingly encourages, and continues to encourage..." (e.g., Compl. ¶¶ 79, 128). No pre-suit knowledge or notice is alleged.

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

  • A core issue will be one of functional interpretation: For the '115 patent, does the accused "air bag" in HP's cartridges actually function by "expanding... for forcing the ink" out, as the claim requires? Or does it serve a different purpose within HP's pressurized system? This presents a central evidentiary question about the true mechanism of the accused products.
  • A second key issue will be one of definitional scope and context: Can the term "lung type pressure regulator" from the '593 patent, which is described in the context of maintaining a passive vacuum ("backpressure"), be construed to read on the accused "air bag" component, which operates within a system that is actively pressurized by an air pump? This raises a fundamental question of whether a component designed for one type of physical environment can infringe when placed in a different one.
  • A third dispositive question will be one of proving functional limits: For the '593 patent, Plaintiff must prove not just that the accused cartridges have a "serpentine" channel, but that this channel "substantially inhibit[s] flow of water vapor," a functional limitation. This will likely require a battle of experts and empirical testing to determine if the accused structure performs this function to the degree required by the claim.