Abstract: A double-head writing instrument has a barrel having a partition formed inside thereof, first and second ink-tanks provided inside the barrel so as not to communicate each other, first and second ink-retaining members connected with first and second nibs provided on an opening of the first and second ink-tanks, respectively, first and second ink reserved inside first and second ink-reservoirs, respectively. The partition is extended in an axial direction so as that the first and second ink-reservoirs overlap each other in a radial direction, and thickness C of the partition and thickness D of a side wall of the barrel connected with the partition satisfy a relation of 0.2?C/D?2.5.

Abstract: A double-head writing instrument has a barrel having a partition formed inside thereof, first and second ink-tanks provided inside the barrel so as not to communicate each other, first and second ink-retaining members connected with first and second nibs provided on an opening of the first and second ink-tanks, respectively, first and second ink reserved inside first and second ink-reservoirs, respectively. The partition is extended in an axial direction so as that the first and second ink-reservoirs overlap each other in a radial direction, and thickness C of the partition and thickness D of a side wall of the barrel connected with the partition satisfy a relation of 0.2?C/D?2.5.

Abstract: A double-head writing instrument has a barrel having a partition formed inside thereof, first and second ink-tanks provided inside the barrel so as not to communicate each other, first and second ink-retaining members connected with first and second nibs provided on an opening of the first and second ink-tanks, respectively, first and second ink reserved inside first and second ink-reservoirs, respectively. The partition is extended in an axial direction so as that the first and second ink-reservoirs overlap each other in a radial direction, and thickness C of the partition and thickness D of a side wall of the barrel connected with the partition satisfy a relation of 0.2?C/D?2.5.

Abstract: A double-head writing instrument has a barrel having a partition formed inside thereof, first and second ink-tanks provided inside the barrel so as not to communicate each other, first and second ink-retaining members connected with first and second nibs provided on an opening of the first and second ink-tanks, respectively, first and second ink reserved inside first and second ink-reservoirs, respectively. The partition is extended in an axial direction so as that the first and second ink-reservoirs overlap each other in a radial direction, and thickness C of the partition and thickness D of a side wall of the barrel connected with the partition satisfy a relation of 0.2?C/D?2.5.

Abstract: A double-head writing instrument has a barrel having a partition formed inside thereof, first and second ink-tanks provided inside the barrel so as not to communicate each other, first and second ink-retaining members connected with first and second nibs provided on an opening of the first and second ink-tanks, respectively, first and second ink reserved inside first and second ink-reservoirs, respectively. The partition is extended in an axial direction so as that the first and second ink-reservoirs overlap each other in a radial direction, and thickness C of the partition and thickness D of a side wall of the barrel connected with the partition satisfy a relation of 0.2?C/D?2.5.

Abstract: A double-head writing instrument has a barrel having a partition formed inside thereof, first and second ink-tanks provided inside the barrel so as not to communicate each other, first and second ink-retaining members connected with first and second nibs provided on an opening of the first and second ink-tanks, respectively, first and second ink reserved inside first and second ink-reservoirs, respectively. The partition is extended in an axial direction so as that the first and second ink-reservoirs overlap each other in a radial direction, and thickness C of the partition and thickness D of a side wall of the barrel connected with the partition satisfy a relation of 0.2?C/D?2.5.

Abstract: A writing instrument has a cap including an inner cylinder portion having an open end and a close end, a cylindrical outer cylinder portion having open ends, a plurality of connection rib integrally connected to an outer surface of the inner cylinder portion and extending in an axial direction and a plurality of vent hole respectively formed between adjacent ones of the connection ribs and a writing instrument body including a pen tip. The open end of the inner cylinder portion extends rearwardly of the connection ribs, the inner cylinder portion seals the pen tip when the cap is fitted on a pen tip side of the writing instrument body and an annular seal portion which is closely contact with an annular airtight portion on the pen tip side of the writing instrument body is provided on the outer peripheral surface of the open end portion of the inner cylinder portion.

Abstract: A writing instrument has a cap including an inner cylinder portion having an open end and a close end, a cylindrical outer cylinder portion having open ends, a plurality of connection rib integrally connected to an outer surface of the inner cylinder portion and extending in an axial direction and a plurality of vent hole respectively formed between adjacent ones of the connection ribs and a writing instrument body including a pen tip. The open end of the inner cylinder portion extends rearwardly of the connection ribs, the inner cylinder portion seals the pen tip when the cap is fitted on a pen tip side of the writing instrument body and an annular seal portion which is closely contact with an annular airtight portion on the pen tip side of the writing instrument body is provided on the outer peripheral surface of the open end portion of the inner cylinder portion.

Abstract: An ink occuluding member made of a porous material is disposed between a pen point and an ink tank. A partition wall is disposed between the ink occuluding member and the ink tank. The partition wall extends in the lengthwise direction. A first communication hole connected to the front portion of the ink occuluding member provided with the pen point is formed in the front portion of the partition wall. A second communication hole connected to the rear portion of the ink occuluding member is formed in the rear portion of the partition wall.

Abstract: The writing implement 1 comprises a shaft barrel 4 and a tail plug 2. The shaft barrel 4 includes an ink storing body 7 stored in an interior portion thereof and a pen point 8 mounted on a front end portion thereof. The tail plug 2 is removably mounted on an opening formed at the rear end of the shaft barrel 4. The tail plug 2 includes a flange portion 21 which is provided backwardly of the rear end portion of the shaft barrel 4. Between the front surface of the flange portion 21 and the rear end portion of the shaft barrel 4, there is formed a groove 5 for forcibly opening. The groove 5 is formed more deeply inwardly in the diameter direction of the shaft barrel 4 than the inner surface of the rear end opening of the shaft barrel 4.

Abstract: A direct ink supply writing implement according to the present invention is provided with an ink reservoir made of a porous material disposed between a nib and an ink tank; a partition wall disposed between the ink reservoir and the ink tank and arranged to partition the ink reservoir and the ink tank from each other; a communication hole formed in the partition wall for establishing communication between the ink reservoir and the ink tank; a rod-shape ink guiding member which penetrates the partition wall and with which ink is supplied from the ink tank to the nib; and a compressed portion formed at a rear end of the ink reservoir and arranged to enhance capillary force as compared with other portions.