If a divisional application is desired, then it must be filed before or at the time of paying the grant fee.
Please be apprised that a divisional application is maintainable in India only for a distinct invention disclosed in the parent application.
In this respect the current stance of the Indian Patent Office (IPO) is that divisional applications are filed in response to the examination reports which bring upon an objection regarding the lack of unity of inventions under Section 10 (5) of the Indian Patents Act, 1970. When filed suo moto, an objection on maintainability of the divisional application is raised in view of Section 16(1) of the Act, wherein the existence of plurality of inventions of the parent application which necessitated filing of the divisional application should be established to the Examiner during the prosecution of the divisional application.
In a case with no objection pertaining to lack of unity of invention raised, it is advisable to file a divisional application only if there is a possibility of explaining to the Examiner the existence of a plurality of inventions in the parent application which necessitated the filing of the divisional.
Furthermore, a divisional application must be filed before a decision is issued in respect of the parent application. Please note that as the IPO does not issue a Notice of Intention to Grant, the application may be granted as soon as we file written submissions in response to the hearing notice. Therefore, in case the Applicant wishes to file a voluntary divisional application, it is advisable to file the same before filing the written submissions, as in case the present application gets granted immediately after filing the written submissions, the Applicant would miss the opportunity to file a divisional application.