“Method of Manufacturing Paper Packaging Container and Paper Packaging Container”


The Plaintiff in this case, requested a reversal of a prior decision rendered in an invalidation trial, in which the Japanese Patent Office (JPO) held the patent at issue to be valid.

Legal Issue:

Error in determining a difference (“Difference A”) between the subject matter of claim 2 of the patent at issue, and German Utility Model No. 29716230(“Exhibit A5″).

Summary of Conclusions:

Exhibit A5 illustrates a slanted roof configuration of a container, in which a front surface panel is lower than a rear surface panel, and right and left triangular folded pieces are formed on a top part.  The court held that while “lateral seal portions” are not illustrated in the Figures of Exhibit A5 nor described in the specification, the two small triangles drawn at the upper side of the tips of the right and left triangular folded pieces disclose the “lateral seal portions”. The court further held that, in the slanted roof configuration of Exhibit A5, the “lateral seal portions” are formed transversely in a lateral direction to have the same length, so that the “lateral seal portions” are positioned closer to the rear.  The court held that consequently, in relation to Difference A, Exhibit A5 includes the configuration in which “a lateral seal provided at a tip portion is located at a side closer to a rear panel than a front panel, and is inclined to a side of the rear panel” as recited in claim 2 of the patent.  Accordingly, the court held that the feature related to Difference A, is common to Exhibit A5 rather than presenting a difference, and that the JPO erred in the finding of a difference with respect to this feature, in the trial decision.


The Defendant alleged that a number of examples of existing slanted roof containers have a “lateral seal” located close to a front, and that the lateral seal is not necessarily positioned close to the rear in terms of the design of a slanted roof container.  However, the court did not adopt the Defendant’s position, stating instead that Exhibit A5 discloses a foldable package container with an inclined top surface which is well known in itself, and that it is natural to understand that the shape of a top surface of Exhibit A5 is in accordance with a general shape known for foldable package containers at the time of the priority date of the patent, and that taking into consideration the overall description of Exhibit A5, it is not reasonable to adopt the elaborate view alleged by the Defendant on the disclosure of Exhibit A5.