Improper modification of cited art in obviousness determination: how to define “principle of operation” or “intended purpose” of the art

Yoshiya Nakamura | February 11, 2015

Plas-Pak Industries v. Sulzer Mixpak AG

January 27, 2015

Panel: Before Lourie, Moore, and Reyna. Opinion by Lourie.


Sulzer Mixpak AG is the owner of Patent No. 7,815,384 (“the 384 patent”).  Plas-Pak Industries (Plas-Pak) is a requester of inter partes reexamination against the 384 patent.  In the reexamination, the examiner decided that the claims of the 384 patent are NOT obvious, and PTAB affirmed the decision.  Plas-Pak appealed to CAFC and argued that PTAB erred in finding that proposed modifications of prior art apparatus are improper because the modifications could destroy a “principle of operation” or “intended purpose” of the prior art apparatus.  CAFC agreed with PTAB’s narrower definition of the “principle operation” or “intended purpose” of prior art and affirmed that the 384 patent are not obvious.

本判決は、引用例の組み合わせに基づく自明性の認定において、主要引用例に第2引用例の要素を組み合わせると主要引用例の動作原理(principle of operation)あるいは意図された目的(intended purpose)を損なう場合は、組み合わせの動機付けがないので自明ではないとした米国特許庁の判断を維持したものである。本件では、主要引用例の改変がその発明の目的達成に必要である要素を取り除くような改変となる場合、あるいは主要引用例の技術の相当な再構築を必要とする場合は引用例の組み合わせを否定すべきであるとされた。引用例の組み合わせは主要引用例の動作原理あるいは意図された目的を損なわない範囲で可能であるというルールは従前とおりであるが、本判決において、先行技術の発明が従来技術に対してどのような技術的貢献を目的としているのか、それをどのような要素あるいはどのようなやり方で達成しているのかに着目して、主要引用例の動作原理や目的の内容をより具体的に定義できることが示唆された。


I. Patented subject matter

The 384 patent relates to apparatuses for mixing, and dispensing multi-component paints.  The representative claim 1 recites:

1.  A device for applying a coating, comprising:

at least two cylindrical cartridges,

a static mixing nozzle in fluid communication with the cartridges,

a spray tip, in fluid communication with the nozzle,

a first flexible hose is disposed between and in fluid communication with the nozzle and the spray tip, and

a second hose, in fluid communication with the spray tip, for supplying atomization air to the spray tip.

II.   Issues and PTO’s decisions

Issue 1: whether there is an error in finding that modification of Fukuta’s apparatus with a mixing and dispensing apparatus (two cylindrical cartridges) of Morris would have changed the “principle of operation” of Fukuta.

Plas-Pak first argues that replacing the components upstream of the mixer 3 (the set of paint suppliers, pumps, and valves, or only the paint suppliers and pumps) in Fukuta’s apparatus with the cartridges 70 of Morris is a simple substitution of known elements.  Plas-Pak particularly argues that the proposed modification does not require a substantial reconstruction of Fukuta simply because the apparatus of Fukuta and the two-component cartridges of Morris are combinable and still able to work as a dispenser.

PTAB disagrees and finds that Fukuta’s “contribution to the art” is not to merely provide an apparatus for bringing a two component mixture, but rather to provide an apparatus with the arrangement and implementation of additional components such as check valves, stop valves, escape valves, etc. for preventing a backflow problem.  Based on the narrower definition of “principle of operation” of Fukuta, PTAB rejected the Plas-Pak’s argument.

Plas-Pak also argues that only the two-component (suppliers and pumps) of Fukuta’s apparatus can be substituted with the cartridges of Morris as such known actuators are generally an obvious variation.  PTAB disagrees and reasons that Plas-Pak still fails to show how such modification would avoid a substantial reconstruction,  PTAB appears to note that it is unknown whether “using the manually actuated mixing gun” of Morris can attain the result intended by Fukuta.

Asserted definitions of “principle of operation”










Morris's apparatus








Issue 2: whether there is an error in finding that modification of Jacobsen’s apparatus with a spray nozzle of Hunter would have rendered the “intended purpose” of Jacobsen inoperable.

Jacobsen discloses a liquid dispensing device for establishing leakproof by directing a fluid into cracks in an underlying structure, while Hunter teaches a conventional spray nozzle.  Plas-Pak first argues that modifying Jacobsen’s apparatus with the spray nozzle of Hunter “would have nothing more than predictable variations of prior art elements.”  PTAB disagrees with the Plas-Pak’s argument by finding that the requester fails to show how the specific function of Jacobsen can be attained by using the spray nozzle of Hunter.   PTAB then concludes that such modification of Jacobsen would render the prior art “unsuitable for its intended purpose of dispensing the components into cracks.”

Asserted definitions of “intended purpose”




III. CAFC decision

Regarding the combination of Fukuta with Morris (issue 1), CAFC agrees with PTAB’s narrower definition of Fukuta’s “principle of operation” and with their finding that the proposed modification would fundamentally alter the principle operation of Fukuta.  CAFC refers to the uniqueness of Fukuta’s invention by citing its disclosures: “the inventors of the present invention have proposed placing stop valves disposed between the junction and the check valve in addition to the construction of the conventional two-component mixing type coating apparatus described above,” and “the present invention [] is characterized . . . by closing the stop valves when the spraying operation of the gun is stopped.”  CAFC then holds that “the Board correctly limited Fukuta’s “principle of operation” to that specific functionality.”

Regarding the combination of Jacobsen with Hunter (issue 2), CAFC agrees with PTAB’s narrower definition of Jacobsen’s “intended purpose” and with the PTAB’s finding that Jacobsen’s dispensing system has the very “specific function of dispensing fluid materials directly into surface[] cracks to minimize leakage.”  CAFC notes that “[a]dding a spray nozzle as Plas-Pak suggests would necessarily undermine that express goal of Jacobsen, i.e., “dispensing fluid materials directly into cracks.”  CAFC also notes that Jacobsen does not teach how a spray nozzle might accomplish the “intended purpose” of “dispensing fluid materials directly into cracks.”   Based on the specific purpose of Jacobsen, CAFC agrees with the PTAB’s decision that modifying Jacobsen to accommodate the spray nozzle of Hunter would render Jacobsen “inoperable for its intended purpose of dispensing fluid materials directly into cracks.”

Take Away

This may be a good case to note if you want to attack the combinability of references where a proposed modification of a main reference would result in requiring substantial reconstruction of the art in the main reference, such as removing or replacing some elements required for the “invention” or “features” (its contribution to the art) of the main reference.

Full Opinion

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