When Does The Patent Practitioner Carry The Burden of Proof?

MARK TERRY, ESQ.

In Ex parte Zechlin, the Board of Patent Appeals and Interferences reiterated that attorney argument alone may not satisfy an applicant’s evidentiary burden during patent prosecution.

The examiner found that a characteristic of the claimed chemical process was inherent in a prior-art process. The applicant disputed that conclusion on appeal but supplied no affidavit, technical literature, experimental evidence, or other supporting material.

When claimed and prior-art products or processes are identical or substantially identical, the USPTO may require the applicant to show that the prior art does not necessarily possess the claimed characteristic. Once a legitimate inherency finding is made, the applicant must come forward with sufficient reasoning, authority, or evidence to rebut it.

The Board held that the applicant did not meet that burden. The practical lesson is that a serious inherency rejection should generally be answered with evidence—potentially including a declaration from a qualified scientist or engineer and supporting technical publications—rather than relying solely on attorney argument.