Section 13 of the Patents Act, 1970 specifically provides that the examiner must conduct an investigation for the purpose of ascertaining whether the invention which the applicant is preparing to apply for its registration for is already in public domain or not? In other words we can say that before applying for the registration of Patent of a novel invention, one has to make sure that the invention is not already in the public domain or has not registered it on a prior basis.
For instance, A filed for complete specification of invention in India, and B claimed over A’s application on prior basis, but A filed its application before B’s and B’s invention being published after the filing of A, then in this case B will anticipate the claims of A by Prior Claim.
Prior claiming is not only limited to examination, but could also be raised by any person at the time of pre-grant opposition under section 25(1) or by a person interested in a post grant opposition unders section 25(2) of the Act.
Clause (c) of subsection (1) of section 25 states that-
That the invention so far is claimed in any claim of the complete specification is claimed in a claim of a complete specification published on or after the priority date of the applicant’s claim and filed in pursuance of an application for a patent in India being a claim of which the priority date is earlier than that of the applicant’s claim.
It can described further as the invention so far as claimed in any claim of the complete specification is claimed in a claim of a complete specification published on or after the priority date of the claim of the patentee and filed in pursuance of an application for a patent in India, being a claim of which a priority date is earlier than that of of the claim of the patentee.
It can be anticipated here that applications which are published prior to the filing of the application for patent registration, could be claimed by the owner before the registry is prior use.
Only in case of seeking revocation of a Patent unders section 64 of the Patent Act, i.e. an application that is filed before the Intellectual Property Appellate Board (IPAB) or in a counter claim against a suit for infringement before a court, does the claim of a earlier complete specification which anticipates by prior claim have to valid claim in a complete specification of a patent grants in India.
Section 64 (1)(a) provides that-
That the invention so far as claimed in any claim of a complete specification, was claimed in a valid claim of earlier priority date contained in the complete specification of another Patent granted in India.
According to the 4th edition of reference to Patent law by P. Narayanan makes clear that in order to establish a prior claim it must be shown that the subject matter of a claim in a specification forms the subject matter of the distinct claim in a cited specification.