Restriction of amendment of claims after the Final OA or Examiner's decision of refusal is issued

When responding to a Final office action or an Examiner's decision of refusal, claim amendment procedures are restricted to following (a) to (d).

(a) Deletion of a claim (Article 17bis(5)(i))
(b) Restriction in a limited way of the claims (Article 17bis(5)(ii))
(c) Correction of errors (Article 17bis(5)(iii))
(d) Clarification of an ambiguous statement (Article 17bis(5)(iv))

Therefore, an examiner will not allow the scope of the claims to be expanded in most cases.  If an applicant would like to expand the scope of claims, it is recommended filing a divisional application.

JPO's Examination guidelines regarding restriction of amendment of claims are described on another page (Link).