When dealing with an allegation that an object or process has been used in such a way that it is comprised in the state of the art (prior use), the division will have to determine the following details:
On the basis of the submissions and the evidence already available, e.g. documents confirming sale, or affidavits related to the prior use, the division will first establish the relevance of the alleged prior use. If on the basis of this assessment it is of the opinion that the prior use is sufficiently substantiated and relevant, and if the prior use is not contested, the division may take a decision using the submissions and the evidence already available. If the prior use or certain circumstances relating to it are contested, the division will need to take further evidence (e.g. hearing witnesses or performing an inspection) for those facts which are relevant to the case and which cannot yet be considered proven on the basis of the evidence already submitted. According to the circumstances of a particular case, such further evidence might have to be submitted by the party(ies). Evidence is always taken under participation of the party(ies), normally in oral proceedings. For details concerning means of evidence see E‑IV, 1.2.
Source: http://www.epo.org/law-practice/legal-texts/html/guidelines/e/g_iv_7_2.htm
Date retrieved: 17 May 2021