.By Zi Wang
In Markem-Imaje Corp. v. Zipher Ltd., 657 F.3d 1293 (Fed. Cir. 2011), the Federal Circuit per curiam majority overturned the district court’s claim construction and summary judgment of noninfringement.
Markem-Imaje Corp. sued Zipher Ltd. and Videojet Technologies, Inc. (together “Zipher”), requesting a declaratory judgment that Zipher’s ‘572 patent is not infringed by Markem. The ‘572 patent is directed to a heat transfer printing apparatus that provides increased control over the acceleration, deceleration, speed, and positional accuracy of the printing operation. In transfer printers in general, the ink ribbon is wound on two spools, one spool for supplying the ribbon for positioning on the substrate, and the other spool for taking up the ribbon after use. Maintaining correct ribbon tension is essential for proper functioning of the printer. The patent specification explains the problems with the mechanism that has been used to provide ribbon tension in prior art printers. It then distinguishes the prior apparatus from what the ‘572 patent calls the “push-pull” mechanism of the ‘572 apparatus, and claims that this new mechanism solves various problems encountered with prior devices. The “push-pull” mechanism is implemented using microcontroller-controlled stepper motors.
Claim 1, the broadest claim of the ‘572 patent, is directed to a tape drive that corrects tension divergences from the predetermined limit in this manner:
A tape drive comprising:
two motors, at least one of which is a stepper motor;
two tape spool supports on which spools of tape are mounted, each spool being driveable by a respective one of said motors;
a controller adapted to control energization of said two motors such that tape is transported in at least one direction between spools of tape mounted on the spool supports;
wherein the controller energizes both said motors to drive the spools in a tape transport direction, and
said controller calculates a length of tape to be added to or subtracted from tape extending between said spools in order to maintain tension in said tape between predetermined limit values and controls said motors to drive the spools to add or subtract the calculated length of tape to or from the tape extending between said spools.
The district court construed “driveable” and “drive” to mean “rotateable” and “rotate”, rejecting Zipher’s broader construction. The district court reasoned that although the ordinary meaning of “drive” can be broad enough to encompass not only the rotation of the spools but also application of a holding torque that prevents the spool from rotating and that references to driving the spools in the specification could accommodate either construction, giving “drive” a meaning broader than “rotation” would be contradictory to the meaning of “drive” in the tape transport clause, which states that “the controller energizes both said motors to drive the spools in a tape transport direction.” Moreover, according to the district court, because the claim clause “controls said motors to drive the spools” already used the word “control,” the patentee could not have intended “control” and “drive” to mean the same thing. The district court also pointed to a few places in the specification that use the word “drive” narrowly. The district court further construed the use of the plural word “spools” in the claim clause “to drive the spools to add or subtract the calculated length of tape” to mean that both spools must rotate to add or subtract a single calculated length of tape.
Because only a single spool is rotated to achieve each tension adjustment in Markem’s accused devices, the district court readily found noninfringement. Zipher then appealed the district court’s claim construction and summary judgment to the Federal Circuit.
On appeal, Zipher argued that “drive”, similar to “control”, has the inclusive meaning of not only rotate but also “hold steady in a commanded position.” Markem, on the other hand, relied on Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc) for its position. Phillips court stated that “claim terms are normally used consistently throughout the patent,” and that “a claim term should be construed consistently with its appearance in other places in the same claim or in other claims of the same patent.” The Federal Circuit majority sided with Zipher, holding that “drive” need not be narrowly construed merely because a broader construction would make it similar to the word “control” that is also used in the claim. The majority also stated that nothing in the specification or the overall invention as presented in the claim and as argued to the patent examiner requires the narrow construction.
In addition to the district court’s construction of “drive the spools”, Zipher also appealed its construction that the claims require “some method of deriving a tension measurement.” The district court opined that “without having a reasonable estimate of the current tape tension, it is not possible to identify whether the tension is approaching or exceeding the limit values.” Zipher argued that since the claim does not recite measuring tension, the district court’s construction would import a limitation into the claims from the specification and violate the mandate of Rambus Inc. v. Infineon Tech. AG, 318 F.3d 1081 (Fed. Cir. 2003) that “the claims need not recite every component necessary to enable operation of a working device.” The majority again agreed with Zipher and drew an analogy with a car engine: “a claim to an engine providing motive power to a car should not be construed to incorporate a limitation for an exhaust pipe, though an engine may not function without one.”
Judge Newman dissented in part. She disagreed with the majority’s reliance on the “mandate” of Rambus. According to Newman, the panel majority ignored “the paramount importance of the specification in claim construction.” Citing a series of cases to support her position, Newman stated that she would hold that “while the invention is flexible as to how tension is measured, and permits measurement through indirect methods, some method of measurement is contemplated and required.”
This is the third time in 2011 that the Federal Circuit has been divided and reached contradictory decisions on the issue as to how to reconcile claim language with the description in the specification. The other two cases are Arlington Industries Inc. v. Bridgeport Fittings Inc.,632 F.3d 1246 (Fed. Cir. 2011), and Retractable Technologies Inc. v. Becton, Dickinson & Co., 653 F.3d 1296 (Fed. Cir. 2011). J. Lourie and CJ. Rader were on opposite sides of the issue in these two cases, each in turn penning the majority opinion in one and the dissenting opinion in the other. The Federal Circuit rejected the opportunity to rehear Retractable en banc in Retractable Technologies Inc. v. Becton Dickinson & Co., 659 F.3d 1369 (Fed. Cir. 2011), before it was presented with the same problem in the present case.
Take-away points: Patent prosecutors should use the same word in a consistent manner throughout the whole application to avoid ambiguity. What’s more, contrary to good general practice in writing, it is probably preferable to stick with the same word when expressing the same idea in patent applications.