3.3.1 Sale to a single customer

According to the established legal practice a single sale was sufficient to render the article sold available to the public within the meaning of Art. 54(2) EPC 1973 provided the buyer was not bound by an obligation to maintain secrecy. It was not necessary to prove that others also had knowledge of the relevant article (T 482/89, OJ 1992, 646, see also T 327/91, T 462/91, T 301/94 and T 783/12).

The sale of an object to a single customer who is not obliged to maintain secrecy renders the invention public, even where the object is to be used in a prototype, which is itself to be kept confidential until it is mass-produced (T 1022/99).

If a product can be analysed, its composition also becomes public on its sale to a third party (T 897/07).