Illinois Tool Works Inc. v. Independent Ink, Inc.

Illinois Tool Works (defendant) sold printing systems combining patented printheads and containers with unpatented ink, requiring manufacturer-buyers to also purchase all their ink exclusively from Illinois Tool as a condition of the license; Independent Ink (plaintiff) began selling competing, identical ink and, after Illinois Tool's infringement suit was dismissed, sued alleging the tying arrangement violated antitrust law. The court of appeals, applying the traditional rule presuming market power from patent ownership, reversed summary judgment for Illinois Tool, and Illinois Tool appealed.