T 476/09 – La Saga Continua

I dedicate this post to my dear friend Dimitris, a true apostle of G 2/98 [6.7].

This is an appeal against the revocation of the patent under consideration.

Claim 1 of the main request on file read:

1. A toner for developing a latent electrostatic image comprising:

a base of toner particle which comprises a binder resin and a coloring agent; and

an external additive,

wherein a plurality of the base of toner particle has a volume average particle diameter (Dv) of 3 µm to 7 µm, a ratio (Dv/Dn) of the volume average particle diameter (Dv) to a number average particle diameter (Dn) is 1.01 to 1.25, a plurality of the base of toner particle comprises 15% by number or less of the base of toner particle having a particle diameter of 0.6 µm to 2.0 µm, a plurality of the base of toner particle has a circularity of 0.930 to 0.990 on average, the binder resin comprises a modified polyester resin, and the toner comprises 0.3 parts by weight to 5.0 parts by weight of the external additive, relative to 100 parts by weight of the base of toner particle. (my emphasis)

One of the questions the Board had to answer was whether this claim was entitled to the claimed priority.

According to the proprietor, the patent was entitled to a priority date of 28 June 2002 for the circularity sub-range of 0.94 to 0.99 which was disclosed in the first priority document, D7. According to G 2/98 multiple priorities for one claim were allowed when two alternative features were claimed. This was confirmed by T 441/93 and T 665/00.

The opponent pointed out that the now claimed combination of technical features was not disclosed in any previous priority document. According to the decision G 2/98, multiple priorities cannot be claimed for so-called “and”-claims where distinct technical features were combined from different priority documents as in the present case. Moreover an arbitrary division of a numerical range such that a part of a claim was entitled with a certain priority date and another part was not entitled with the priority date was not allowable according to established practice at the EPO.

What was the Board’s verdict?

[5.1] The patent in suit claims two priority dates, the first priority date being 28 June 2002 from D7 and the second priority being 17 September 2002 from D8.

[5.2] D6 is an intermediate document having been published on 26 March 2003, after the two priority dates of the patent in suit and before the filing date thereof. In as far as the priorities of the patent in suit are valid, D6 is prior art under A 54(3) only and hence not relevant to inventive step. It therefore has to be decided whether the claims of the patent are entitled to the claimed priority right. In this respect, it has to be decided whether in the priority document(s) the same invention is disclosed as in the patent in suit (A 87(1)).

[5.3] Each claim 1 of the main request and auxiliary requests 1 to 3 refers to a toner comprising a base of toner particles and contains the requirement that the average circularity of the base of toner particles is in the range of 0.930 to 0.990.

[5.4] Priority document D8 discloses this circularity range but does not describe the remaining features of claim 1. It was therefore accepted by both parties that the patent in suit does not enjoy the priority of D8.

[5.5] It was also common ground that priority document D7 discloses all features of claim 1 in combination, except for the circularity, which is defined in D7 in a narrower range of 0.94 to 0.99. It was a matter of dispute between the parties whether out of the range of 0.930 to 0.990 in claim 1 of the appellant’s requests, the partial range of 0.94 to 0.99 enjoys the priority of D7.

[5.6] In this respect, decision G 2/98 [6.7] is relevant. In this decision the Enlarged Board of Appeal allowed the use of a generic term or formula in a claim for which multiple priorities were claimed, but that was made under the provision that such term « gives rise to the claiming of a limited number of clearly defined alternative subject-matters ». In the present case, however, the claimed range represents a continuum of a numerical range of values which does not correspond to distinctive alternative embodiments. Consequently, no separable alternative embodiments can be identified within this continuum which could enjoy the priority date of D7.

This is confirmed by the decision T 1877/08 [2.4]. In this decision priority was denied for a composition that was characterised by ranges overlapping with the corresponding ranges disclosed in the priority document, because no separable alternative embodiments could be identified in the ranges.

[5.7] The appellant in this respect cited decisions T 441/93 and T 665/00 in support of its arguments.

In T 441/93 multiple priorities were allowed but, contrary to the present case, in a situation wherein clearly separable alternatives were present (embodiment directed to the transformation of protoplasts versus embodiment not directed to the transformation of protoplasts).

In T 665/00 the question arose whether one specific value out of a range present in a claim could enjoy priority. This is different however from the present case which concerns the priority of a partial range rather than of one individual value. The case in T 665/00 differs further from the present one in that the specific value had been disclosed specifically in the priority document by way of an example.

[5.8] For these reasons no priority has been validly claimed for the subject-matter of claim 1 of the main request and auxiliary requests 1 to 3 with the consequence that document D6 is prior art pursuant to A 54(2).

Should you wish to download the whole decision, just click here.

The file wrapper can be found here.