Writing instrument refill

Abstract

A writing instrument refill includes an ink storage tube storing an ink therein, a pen tip provided on a distal end side of the ink storage tube and including a writing part, and a pen tip holder to which the ink storage tube and the pen tip are respectively connected. The ink storage tube is a tubular body made of a metal. A rear end side outer circumferential surface of the pen tip holder and a front end side inner circumferential surface of the ink storage tube are press-fit inserted. A circumferential swaged part is formed on a front end side outer circumferential surface of the ink storage tube, and an outer diameter of the ink storage tube in the vicinity of the circumferential swaged part is φ4.5 mm or more. The circumferential swaged part is formed of a straight surface having a constant outer diameter in an axial direction and tapered surfaces formed on both front and rear sides of the straight surface.

Dependencies are inferred from the claim text.