Generally, a claim’s preamble does not limit the scope of the claim. However, a preamble can limit claim scope when it breathes life and meaning into the claim. For example, a preamble may limit the claim scope when it provides antecedent support to recitations in the main body of the claim.

Patent drafters that effectively craft a preamble, even in claims where the preamble is limiting, can assist in overcoming later potential joint infringement issues. Infringement of a patented method requires that a single entity perform all the steps of the method. See McKesson Techs., Inc. v. Epic Sys. Corp., No. 2010-1291 (Fed. Cir. Apr. 12, 2011).

Under this rule, a patent claim requiring the actions of more than one party is infringed only when the accused infringer exercises direction and control over the third party. Notwithstanding this general rule, even if a preamble limits the claim scope by describing the environment in which the claim is performed, an accused infringer that performs only the steps in the body of the claim in the environment recited in the preamble infringes the claim.

A patent drafter can write steps requiring action by a third party in the patent preamble to avoid a potential joint infringement problem. For example, in a recent case decided by the Federal Circuit, Advanced Software asserted a method claim against Fiserv’s check security product that prevents fraud and forgery. The asserted claim contained three main steps: encrypting, printing, and validating. Both the encrypting and printing steps were recited in the claim’s preamble, while the validating step was in the body of the claim. Under McKesson, Fiserv argued that it did not infringe because it only performed one of the three disclosed steps and did not perform the two method steps of the preamble. However, the Federal Circuit found that the steps listed in the preamble of the method claim “define the environment in which an accused infringer must act or describe capabilities that an accused device must have.” Advanced Software Design Corp. v. Fiserv, Inc., No. 2009-1585, slip op. at 9 (Fed. Cir. June 2, 2011). The Court found that the preamble’s steps, while limiting, need not be performed by the direct infringer. The direct infringer need only perform the method steps in the body of the claim within the environment described by the preamble. Because Fiserv validated checks that had been encrypted and printed in accordance with the steps in the preamble, it infringed the asserted claim.

The Advanced Software Court relied on its earlier 2011 decision in Uniloc USA, Inc. v. Microsoft Corp. to resolve this joint infringement issue. 632 F.3d 1292 (Fed. Cir. 2011). The asserted claim in Uniloc covered a remote registration station that incorporates a “remote licensee unique ID generating means.” Microsoft admittedly supplied a remote registration station but did not supply or use the local licensee unique ID generating means. Nonetheless, the Court found that the claim exclusively covered a remote registration station. The portion of the claim discussing the unique ID generating means merely described the environment in which the claimed element must function. Thus, the Court found Microsoft guilty of infringement for supplying a remote registration station for use in the claimed environment.

To avoid potential joint infringement issues, patent drafters should draft method claims to a single entity. The Advanced Software case explains that, at least under the facts of that case, only the body of the claim must be drafted to a single entity, while the preamble can describe an environment requiring third parties to act. For example, a patent drafter can draft a claim such that a single entity can perform all of the method steps in the body of the claim and would likely perform these method steps in an environment described in the preamble. This type of patent drafting can avoid potential joint infringement issues, making it easier for a patentee to enforce its patent rights.