Abstract: A tail plug to be attached to a tail end of a shaft part of a writing instrument includes an inner plug that is fitted into the shaft part and an outer plug that is coupled with the inner plug. The inner plug has a first opening through which a fluid can flow in an axial direction of the shaft part; the outer plug has a second opening through which a fluid can flow in the axial direction of the shaft part, and at least one of the first opening and the second opening are configured to be closed when the outer plug and the inner plug are coupled with each other.

Abstract: A is a pen including: an ink reservoir that stores an ink including decorative particles and a pen tip section. The ink reservoir includes a tubular casing member having liquid blocking properties and an ink occlusion material disposed inside the casing member. The casing member has a first opening end and a second opening end. The ink occlusion material includes multiple fibers disposed in the casing member and the multiple fibers respectively having one ends and other ends each disposed at a position corresponding to the first opening end or the second opening end of the casing member.

Abstract: Provided is a tail plug to be attached to a tail end of a shaft part of a writing instrument. The tail plug includes an inner plug that is fitted into the shaft part and an outer plug that is coupled with the inner plug. The inner plug has a first opening through which a fluid can flow in an axial direction of the shaft part; the outer plug has a second opening through which a fluid can flow in the axial direction of the shaft part, and at least one of the first opening and the second opening are configured to be closed when the outer plug and the inner plug are coupled with each other.

Abstract: A pen includes: an ink reservoir configured to store an ink; and a pen tip section including an ink application part configured to apply the ink to an ink application object. The ink application part of the pen tip section includes: a rigid tip made of a rigid material and having a hemispherical outer surface, an inner surface facing toward the ink reservoir, and a penetration part penetrating from the inner surface side to the outer surface side of the rigid tip; and at least one foam body filled in the penetration part at least on the side of the penetration part close to the outer surface side of the rigid tip, and provided with at least one air bubble formed to communicate from the outer surface side of the foam body to the inner surface side of the foam body.

Abstract: Provided is a pen including: an ink reservoir that stores an ink including decorative particles and a pen tip section. The ink reservoir includes a tubular casing member having liquid blocking properties and an ink occlusion material disposed inside the casing member. The casing member has a first opening end and a second opening end. The ink occlusion material includes multiple fibers disposed in the casing member and the multiple fibers respectively having one ends and other ends each disposed at a position corresponding to the first opening end or the second opening end of the casing member.

Abstract: A pen includes: an ink reservoir configured to store an ink; and a pen tip section including an ink application part configured to apply the ink to an ink application object. The ink application part of the pen tip section includes: a rigid tip made of a rigid material and having a hemispherical outer surface, an inner surface facing toward the ink reservoir, and a penetration part penetrating from the inner surface side to the outer surface side of the rigid tip; and at least one foam body filled in the penetration part at least on the side of the penetration part close to the outer surface side of the rigid tip, and provided with at least one air bubble formed to communicate from the outer surface side of the foam body to the inner surface side of the foam body.