Patent attributes
The outer surface of an inner cap 3 is fixedly secured to the inner surface of an outer cap 4. In the opened end portion of the inner cap 3, there is formed a rear end shell portion 31 which projects backwardly. On the outer peripheral surface of the rear end shell portion 31, there is provided a ring-shaped outward facing seal portion. In the front end portion of a barrel 6, there is formed a front end shell portion 61 projecting forwardly. In the inner peripheral surface of the front end shell portion 61, there is formed a ring-shaped inward facing seal portion. When a cap 2 is mounted on the pen tip 8 side of the barrel 6, the outward facing seal portion can be closely contacted with the inward facing seal portion in the radial direction.
