The substantive examination of a divisional application should in principle be carried out as for any other application but the following special points need to be considered. The claims of a divisional application need not be limited to subject-matter already claimed in claims of the parent application. Furthermore, no abuse of the system of divisional applications can be identified in the mere fact that the claims of the application on which the Examining Division had then to decide had a broader scope than the claims granted in relation with the parent application (see T 422/07).
However, under Art. 76(1), the subject-matter may not extend beyond the content of the parent application as filed. If a divisional application as filed contains subject-matter additional to that contained in the parent application as filed, it can be amended later in order that its subject-matter no longer extends beyond the earlier content, even at a time when the earlier application is no longer pending (see G 1/05). If the applicant is unwilling to remedy the defect by removal of that additional subject-matter, the divisional application must be refused under Art. 97(2) due to non-compliance with Art. 76(1).
It cannot be converted into an independent application taking its own filing date. Moreover, a further divisional application for this additional subject-matter should also be refused under Art. 97(2) due to non-compliance with Art. 76(1).
Amendments made to a divisional application subsequent to its filing must comply with the requirements of Art. 123(2), i.e. they may not extend the subject-matter beyond the content of the divisional application as filed (see G 1/05 and T 873/94). If those amendments have not been identified and/or their basis in the application as filed not indicated by the applicant (see H-III, 2.1) and the application is one of those mentioned in H-III, 2.1.4, the Examining Division may send a communication according to Rule 137(4) requesting the applicant to provide this information (see H-III, 2.1.1).
If the subject-matter of a divisional application is restricted to only a part of the subject-matter claimed in the parent application, this part of the subject-matter must be directly and unambiguously derivable from the parent application as being a separate part or entity, i.e. one which can even be used outside the context of the invention of the parent application (see T 545/92).
In the case of a sequence of applications consisting of a root (originating) application followed by divisional applications, each divided from its predecessor, it is a necessary and sufficient condition for a divisional application of that sequence to comply with Art. 76(1), second sentence, that anything disclosed in that divisional application be directly and unambiguously derivable from what is disclosed in each of the preceding applications as filed (see G 1/06).