T 0156/84 (Pressure swing adsorption) of 09.04.1987

1. The principle of examination by the EPO of its own motion (Article 114(1) EPC) takes precedence over the possibility of disregarding facts or evidence not submitted in due time. This follows from the EPO's duty vis-à-vis the public not to grant or maintain patents which it is convinced are not legally valid.

2. The EPO has to examine the relevance of citations introduced late into the proceedings and has to communicate the results to the parties at least in its decision. No final decision on the opposition can be taken until such an examination has been performed.

3. Late-filed documents can be designated as not material by the EPO without having to give detailed reasons as it does in the case of citations referred to in due time.

4. Late-filed documents are not deemed not to have been submitted in due time simply because they have not been submitted during the opposition period; if careful preparation of the opposition proceedings would have revealed the late-filed documents earlier, it is the opponent's task to set out the circumstances that prevented him from mentioning the documents earlier.