Patent ID: 7942598

Claim:
A writing implement, comprising: a cap comprising: an inner cap having a closed front end portion and an opened rear end portion; and an outer cap fixed to an outer surface of the inner cap, at least a rear end of the outer cap being opened; and a writing implement main body for mounting the cap removably thereon, and including a barrel having a pen tip on a front end portion and an ink storing member disposed inside the barrel, wherein, when the cap is mounted on the pen tip side of the barrel, the inner cap seals the pen tip and an inner surface of the outer cap is fitted with an outer surface of the barrel, a backwardly projecting rear end shell portion is formed in the opened rear end portion of the inner cap, a non-threaded ring-shaped outward facing seal portion is formed in an outer peripheral surface of the rear end shell portion, a forwardly projecting front end shell portion is formed in the front end portion of the barrel, a non-threaded ring-shaped inward facing seal portion is formed in an inner peripheral surface of the front end shell portion, a removal preventive projection is formed in the front end portion of the barrel rearward of the non-threaded ring-shaped inward facing seal portion of the barrel, the removal preventive projection retaining the ink storing member within the barrel, and when the cap is mounted onto the pen tip side of the barrel, the outward facing seal portion closely contacts with the inward facing seal portion in a radial direction and a first fitting projection on an inner surface of the outer cap is moved over and fitted with a second fitting projection on an outer surface of the barrel by the first fitting projection moving out of engagement with the second fitting projection in an axial direction and back into engagement with the second fitting projection, wherein an axial-direction close contact sliding length between the ring-shaped outward facing seal portion and the ring-shaped inward facing seal portion is set in a range of 0.1 mm to 1.0 mm.