Slingshot Sues HP Over Alleged Inkjet Patent-Infringement

In a bit of an odd case, HP Inc. is being sued by Slingshot Printing, a non-practicing patent holder – otherwise known as a ” patent troll” – for alleged patent-infringement of 16 inkjet-printer patents by that were developed by Lexmark International decades ago. The case was filed on June 11th in the U.S. District Court for the Western District of Texas, Waco Division.


The inkjet-printer patents were developed by Lexmark before it sold its inkjet technology and patents to Funai Electric Company of Japan for $100 million in 2013. Subsequently, Slingshot says that it purchased the patents from Funai for an undisclosed sum.

Among the patents are a patent involving technology for supplying and delivering ink through an ink-cartridge system (U.S. Patent No. 6,243,115); a vent system for an “inkjet pen” (U.S. Patent No. 6,394,593); a pressure-controlled inkjet print-head assembly (U.S. Patent No. 6,817,707); and an improved fluid-supply tank for a micro-fluid injection head U.S. Patent No. 7,938,523).

Slingshot also alleges that HP infringed upon U.S Patent No. 6,137,502, U.S. Patent No. 7,244,015, U.S. Patent No. 7,014,299, U.S. Patent No.. 6,213,587, U.S. Patent No. 6,485,124, U.S. Patent No. Patent No. 6,666,449, U.S. Patent No. 6,773,088, U.S. Patent Patent No. 7,311,385, U.S. Patent No. 7,819,498, and U.S. Patent No. 8,113,618.

Slingshot alleges that a long list of HP inkjet printers infringe upon at least one of the patents, including various Deskjet, Envy, Photosmart, and OfficeJet, and OfficeJet Pro models.

Slingshot also asserts that various HP inkjet printers and ink cartridges infringe upon these patents. It alleges that these ink cartridges infringe upon at least one of the patents: HP 60, HP 60XL, HP 61, HP 61XL, HP 62, HP 62XL, HP 63, HP 63 XL, HP 64, HP 64 XL, HP 65, HP 65XL, HP 97, HP 564, HP 564XL, HP 902, HP 902XL, HP 920XL, HP 931, HP 951, HP 971 HP 932, HP 933, HP 950, HP 950XL, HP 970, HP 970 XL, HP 971 XL, HP 972, and HP 980.

Slingshot is requesting a jury trail and damages.

The lawsuit filings – which contains an interesting history of the development of inkjet printing – can be accessed here, here, and here.

Our Take

We aren’t patent attorneys, but it seems likely that HP may argue that it hasn’t infringed upon the Lexmark patents either because a) its inkjet technology is substantially different from the technology developed by Lexmark, or b) HP’s inkjet technology was developed before or at the same time as the Lexmark technology, and thus Lexmark had no actual legal right to patent it.

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