JP4680751B2

JP4680751B2 - Writing instrument

Info

Publication number: JP4680751B2
Application number: JP2005325801A
Authority: JP
Inventors: 久嗣岩田
Original assignee: Pilot Ink Co Ltd
Current assignee: Pilot Ink Co Ltd
Priority date: 2004-12-24
Filing date: 2005-11-10
Publication date: 2011-05-11
Anticipated expiration: 2025-11-10
Also published as: JP2006199024A

Description

本発明は、筆記具に関する。尚、本発明で「前」とは、キャップの閉塞側及び筆記具本体のペン先側を指し、「後」とは、キャップの開口側及び筆記具本体のインキタンク側を指す。 The present invention relates to a writing instrument. In the present invention, “front” refers to the closed side of the cap and the pen tip side of the writing instrument body, and “rear” refers to the opening side of the cap and the ink tank side of the writing instrument body.

従来、この種の筆記具において、特許文献１には、「ペン先を備えた軸筒の先端部に内部にインナキャップを備えたキャップを装着してキャップ内部を気密に保つ筆記具のキャップ装着構造であって、前記インナキャップを軟質弾性樹脂材で成形するとともに、前記キャップを前記軸筒に装着したときに互いに圧接する前記軸筒の先端面および／またはインナキャップの端面部分に環状の突起を設けたことを特徴とする筆記具のキャップ装着構造」が開示されている。
実開平２−１４４４８８号明細書 Conventionally, in this type of writing instrument, Patent Document 1 states that “a cap mounting structure for a writing instrument that keeps the inside of the cap airtight by attaching a cap with an inner cap to the tip of a shaft cylinder with a pen tip. The inner cap is formed of a soft elastic resin material, and an annular protrusion is provided on a front end surface of the shaft tube and / or an end surface portion of the inner cap which are in pressure contact with each other when the cap is mounted on the shaft tube. A writing instrument cap mounting structure characterized by the above is disclosed.
Japanese Utility Model Publication No. 2-144488

前記特許文献１のキャップは、キャップ装着時に、ペン先がインナキャップの端面の環状突起（気密シール部）に接触し、環状突起にインキが付着し環状突起を汚すおそれや、あるいは環状突起を損傷させ気密不良を発生させるおそれがある。 In the cap of Patent Document 1, when the cap is attached, the pen tip may contact the annular protrusion (airtight seal portion) on the end surface of the inner cap, and ink may adhere to the annular protrusion to contaminate the annular protrusion or damage the annular protrusion. There is a risk of causing airtight defects.

特に、前記環状突起にインキが付着すると、環状突起に付着したインキがキャップ装着によって、軸筒に付着し、その軸筒を把持した際に手にインキが付着し、手が汚れるおそれがある。 In particular, when ink adheres to the annular protrusion, the ink attached to the annular protrusion adheres to the shaft cylinder when the cap is attached, and when the shaft cylinder is gripped, the ink may adhere to the hand and the hand may become dirty.

また、前記特許文献１のキャップ装着構造は、軸筒の前端面に気密シール部が形成され、該気密シール部が外部に露出しているため、誤って気密シール部を傷つけ、気密不良が発生するおそれがある。 Further, in the cap mounting structure of Patent Document 1, an airtight seal portion is formed on the front end surface of the shaft cylinder, and the airtight seal portion is exposed to the outside, so that the airtight seal portion is accidentally damaged and an airtight defect occurs. There is a risk.

また、前記特許文献１のキャップ装着構造は、キャップ装着時のインナキャップ内部の空気を圧縮すること回避する目的で、軸筒との固定用の環状突起に切り欠きが形成されている。それにより、前記特許文献１のキャップ装着構造は、インナキャップ内部の空気が、軸筒外面とキャップ内面との隙間を通って、キャップの開口端部から外部に排出される構造である。しかし、前記軸筒外面とキャップ内面との間の隙間は、実際、あまり大きく設定できないため、キャップ装着動作が急激に行われた場合、キャップ内の加圧空気（圧縮空気）が外部に十分に排出できず、軸筒内に加圧空気を入れたり、あるいは、キャップ取り外し動作が急激に行われた場合、キャップ内の空気が減圧されることにより、ペン先側よりインキが漏出するおそれがある。 In addition, the cap mounting structure of Patent Document 1 has a notch formed in an annular protrusion for fixing to the shaft tube in order to avoid compressing the air inside the inner cap when the cap is mounted. Thereby, the cap mounting structure of Patent Document 1 is a structure in which air inside the inner cap is discharged to the outside through the gap between the outer surface of the shaft tube and the inner surface of the cap. However, since the gap between the outer surface of the shaft cylinder and the inner surface of the cap cannot actually be set so large, when the cap mounting operation is performed rapidly, the compressed air (compressed air) in the cap is sufficiently outside. If the air cannot be discharged and pressurized air is put into the cylinder or the cap is removed rapidly, the air in the cap may be decompressed, causing ink to leak out from the pen tip side. .

本発明は前記従来の課題を解決するものであって、キャップ装着時にキャップ内の気密シール部にペン先が接触することを回避して、キャップ内の気密シール部の損傷及び気密シール部へのインキ付着を防止し、また、軸筒の気密シール部の損傷を防止し、しかも、急激なキャップ装着が行われた場合でもキャップ内部の空気を加圧することを十分に回避できるとともに、急激なキャップ取り外しが行われた場合でもキャップ内部の空気を減圧することを十分に回避できる筆記具を提供しようとするものである。 The present invention solves the above-described conventional problems, and avoids contact of the pen tip with the hermetic seal portion in the cap when the cap is attached, and damages to the hermetic seal portion in the cap and to the hermetic seal portion. Prevents ink adhesion, prevents damage to the airtight seal part of the cylinder, and even when the cap is suddenly attached, it is possible to sufficiently avoid pressurizing the air inside the cap and An object of the present invention is to provide a writing instrument that can sufficiently avoid depressurizing the air inside the cap even when the cap is removed.

本発明は、前端が閉鎖され且つ後端が開口された内キャップと、前記内キャップの外面に固着され且つ少なくとも後端が開口された外キャップとからなるキャップと、前記キャップが着脱自在の、前端にペン先を有する軸筒を備えた筆記具本体とからなり、前記キャップを前記軸筒のペン先側に装着した際、前記内キャップがペン先を密封し、前記外キャップの内面と前記軸筒の外面とが嵌合してなる筆記具であって、前記内キャップの開口端部に、後方に突出する後端筒部を形成し、前記後端筒部の外周面に環状の外向シール部を形成し、前記外キャップの側壁または頂壁に通気孔を貫設し、一方、前記軸筒の前端部に、前方に突出する前端筒部を形成し、前記前端筒部の内周面に環状の内向シール部を形成し、キャップを軸筒のペン先側に装着した際、前記外向シール部と前記内向シール部とが径方向に密接し、前記外向シール部と前記内向シール部とが密接状態にない場合、前記通気孔を介してキャップ内部と外気とが連通してなり、前記通気孔が、前記内キャップの後端筒部の径方向外方の外キャップの側壁に貫設され、前記通気孔が内キャップの開口端部近傍に位置すること（構成１）を特徴とする。 The present invention comprises a cap comprising an inner cap having a front end closed and a rear end opened, an outer cap fixed to an outer surface of the inner cap and at least a rear end opened, and the cap is detachable. A writing instrument body having a shaft cylinder having a pen tip at the front end, and when the cap is mounted on the pen tip side of the shaft tube, the inner cap seals the pen tip, and the inner surface of the outer cap and the shaft A writing instrument formed by fitting with an outer surface of a cylinder, wherein a rear end cylindrical portion protruding rearward is formed at an opening end portion of the inner cap, and an annular outward seal portion is formed on an outer peripheral surface of the rear end cylindrical portion. And a vent hole is formed through the side wall or the top wall of the outer cap, while a front end tube portion protruding forward is formed at the front end portion of the shaft tube, and an inner peripheral surface of the front end tube portion is formed. An annular inward seal is formed, and the cap is on the pen tip side of the shaft When the outer seal part and the inward seal part are in close contact with each other in the radial direction when mounted, and the outer seal part and the inward seal part are not in close contact with each other, the inside of the cap and the outside air are connected via the vent hole. Ri Na communicating, said vent, formed through the side wall of the outer cap radially outward of the rear cylindrical portion of the internal cap, the vent is located near the open end of the inner cap ( It is characterized by Configuration 1 ).

本発明は、前端が閉鎖され且つ後端が開口された内キャップと、前記内キャップの外面に一体に連結され、前端が閉鎖され且つ後端が開口された外キャップとからなるキャップと、前記キャップが着脱自在の、前端にペン先を有する軸筒を備えた筆記具本体とからなり、前記キャップを前記軸筒のペン先側に装着した際、前記内キャップがペン先を密封し、前記外キャップの内面と前記軸筒の外面とが嵌合してなる筆記具であって、前記内キャップの開口端部に、後方に突出する後端筒部を形成し、前記後端筒部の外周面に環状の外向シール部を形成し、前記外キャップの側壁または頂壁に通気孔を貫設し、一方、前記軸筒の前端部に、前方に突出する前端筒部を形成し、前記前端筒部の内周面に環状の内向シール部を形成し、キャップを軸筒のペン先側に装着した際、前記外向シール部と前記内向シール部とが径方向に密接し、前記外向シール部と前記内向シール部とが密接状態にない場合、前記通気孔を介して内キャップ内部と外キャップ外部とが連通してなり、前記通気孔が、前記内キャップの後端筒部の径方向外方の外キャップの側壁に貫設され、前記通気孔が内キャップの開口端部近傍に位置すること（構成２）を特徴とする。 The present invention comprises an inner cap having a front end closed and a rear end opened, and an outer cap integrally connected to the outer surface of the inner cap, the front end being closed and the rear end being opened, A writing instrument body having a shaft cylinder having a nib at the front end, the cap being detachable, and when the cap is mounted on the pen nib side of the shaft cylinder, the inner cap seals the nib and the outer A writing instrument in which an inner surface of a cap and an outer surface of the shaft tube are fitted to each other, and a rear end tube portion protruding rearward is formed at an opening end portion of the inner cap, and an outer peripheral surface of the rear end tube portion An annular outward seal portion is formed, and a vent hole is formed through a side wall or a top wall of the outer cap. On the other hand, a front end cylindrical portion protruding forward is formed at a front end portion of the shaft cylinder, and the front end cylinder is formed. An annular inward seal is formed on the inner peripheral surface of the When the outer seal portion and the inward seal portion are in close contact with each other in the radial direction and the outward seal portion and the inward seal portion are not in close contact with each other, Ri Na communicates with the cap inside the outer cap outside, the vent hole is formed through the side wall of the outer cap radially outward of the rear cylindrical portion of the internal cap, the vent hole of the inner cap opening It is characterized by being located in the vicinity of the end (Configuration 2 ).

本発明は、前記外向シール部よりも前方の内キャップ外面に、前記軸筒の前端筒部の前端が当接可能な規制壁部を形成したこと（構成３）を特徴とする。 The present invention is characterized in that a regulating wall portion with which the front end of the front end tube portion of the shaft tube can abut is formed on the outer surface of the inner cap in front of the outward seal portion (Configuration 3 ).

本発明は、前記内向シール部よりも後方の軸筒内面に、前記内キャップの後端筒部の後端が当接可能な規制壁部を形成したこと（構成４）を特徴とする。 The present invention is characterized in that a regulating wall portion with which the rear end of the rear end cylinder portion of the inner cap can abut is formed on the inner surface of the shaft cylinder behind the inward seal portion (Configuration 4 ).

本発明は、前記外向シール部と前記内向シール部との軸方向の密接摺動長さを、０．１ｍｍ〜１．０ｍｍの範囲に設定したこと（構成５）を特徴とする。 The present invention is characterized in that an axial close sliding length between the outward seal portion and the inward seal portion is set in a range of 0.1 mm to 1.0 mm (Configuration 5 ).

本発明は、前記筆記具本体が、ペン先を前端に備えるインキ保溜部材と、該インキ保溜部材を前部に収容した軸筒と、該軸筒内の前記インキ保溜部材の後方に形成したインキタンクとを備え、前記インキ保溜部材が、前記インキタンク内の内圧上昇に応じた余剰インキを一時的に保持してなること（構成６）を特徴とする。 In the present invention, the writing instrument main body is formed behind an ink reservoir member having a pen tip at the front end, a shaft cylinder housing the ink reservoir member in a front portion, and the ink reservoir member in the shaft cylinder. The ink storage member temporarily holds excess ink corresponding to an increase in internal pressure in the ink tank (Configuration 6 ).

本発明は、前記規制壁部よりも後方の後端筒部が薄肉円筒状であること（構成７）を特徴とする。 The present invention is characterized in that the rear end cylinder part behind the regulation wall part is a thin cylindrical shape (Configuration 7 ).

本発明は、前記規制壁部よりも前方の前端筒部が薄肉円筒状であること（構成８）を特徴とする。 The present invention is characterized in that the front end cylinder portion in front of the restriction wall portion is a thin-walled cylinder (Configuration 8 ).

本発明は、前記通気孔の総開口面積が０．５ｍｍ^２以上であること（構成９）を特徴とする。 The present invention is characterized in that the total opening area of the vent holes is 0.5 mm ² or more (Configuration 9 ).

請求項１の筆記具によれば、キャップ装着時にキャップ内の気密シール部にペン先が接触することを回避して、キャップ内の気密シール部の損傷及び気密シール部へのインキ付着を防止し、また、軸筒の気密シール部の損傷を防止できる。しかも、急激なキャップ装着が行われた場合でもキャップ内部の空気を加圧することを十分に回避できるとともに、急激なキャップ取り外しが行われた場合でもキャップ内部の空気を減圧することを十分に回避できる。 According to the writing instrument of claim 1 , the pen tip is prevented from coming into contact with the hermetic seal portion in the cap when the cap is attached, and damage to the hermetic seal portion in the cap and ink adhesion to the hermetic seal portion are prevented, Moreover, damage to the hermetic seal portion of the shaft cylinder can be prevented. Moreover, it is possible to sufficiently avoid pressurizing the air inside the cap even when the cap is suddenly attached, and to sufficiently depressurize the air inside the cap even when the cap is suddenly removed. .

請求項２の筆記具によれば、キャップ装着時にキャップ内の気密シール部にペン先が接触することを回避して、キャップ内の気密シール部の損傷及び気密シール部へのインキ付着を防止し、また、軸筒の気密シール部の損傷を防止できる。しかも、急激なキャップ装着が行われた場合でもキャップ内部の空気を加圧することを十分に回避できるとともに、急激なキャップ取り外しが行われた場合でもキャップ内部の空気を減圧することを十分に回避できる。 According to the writing instrument of claim 2 , when the cap is attached, the pen tip is prevented from coming into contact with the hermetic seal portion in the cap, and damage to the hermetic seal portion in the cap and ink adhesion to the hermetic seal portion are prevented, Moreover, damage to the hermetic seal portion of the shaft cylinder can be prevented. Moreover, it is possible to sufficiently avoid pressurizing the air inside the cap even when the cap is suddenly attached, and to sufficiently depressurize the air inside the cap even when the cap is suddenly removed. .

請求項３の筆記具によれば、外向シール部と内向シール部とが密接を開始してから終了するまでの軸方向の移動長さ（即ち密接摺動長さ）を一定に保つことができる。 According to the writing instrument of the third aspect , it is possible to keep the axial movement length (that is, the close sliding length) from the start to the end of the close contact between the outward seal portion and the inward seal portion.

請求項４の筆記具によれば、外向シール部と内向シール部とが密接を開始してから終了するまでの軸方向の移動長さ（即ち密接摺動長さ）を一定に保つことができる。 According to the writing instrument of the fourth aspect , the axial movement length (that is, the close sliding length) from when the outward seal portion and the inward seal portion start to close to each other can be kept constant.

請求項５の筆記具によれば、外向シール部と内向シール部との十分なシール性が得られ、且つ、キャップ装着時に内キャップ内の空気を加圧することを十分に回避できるとともに、キャップ取り外し時に内キャップ内の空気を減圧することを十分に回避できる。 According to the writing instrument of claim 5 , sufficient sealing performance between the outward seal portion and the inward seal portion is obtained, and it is possible to sufficiently avoid pressurizing the air in the inner cap when the cap is mounted, and at the time of removing the cap. Depressurizing the air in the inner cap can be sufficiently avoided.

請求項６の筆記具によれば、前記請求項１乃至請求項５による効果を備えた直液式筆記具を得る。 According to the writing instrument of the sixth aspect , a direct liquid writing instrument having the effects of the first to fifth aspects is obtained.

請求項７の筆記具によれば、後端筒部の径方向の弾性変形を容易にし、後端筒部の外周面の外向シール部と前端筒部の内周面の内向シール部とのスムーズな密接摺動を可能にする According to the writing instrument of claim 7 , the elastic deformation in the radial direction of the rear end tube portion is facilitated, and the outward seal portion on the outer peripheral surface of the rear end tube portion and the inward seal portion on the inner peripheral surface of the front end tube portion are smooth. Enable close sliding

請求項８の筆記具によれば、前端筒部の径方向の弾性変形を容易にし、後端筒部の外周面の外向シール部と前端筒部の内周面の内向シール部とのスムーズな密接摺動を可能にする。 According to the writing instrument of claim 8 , the elastic deformation in the radial direction of the front end tube portion is facilitated, and the smooth intimate contact between the outward seal portion on the outer peripheral surface of the rear end tube portion and the inward seal portion on the inner peripheral surface of the front end tube portion. Allows sliding.

請求項９の筆記具によれば、急激なキャップ着脱動作が行われた場合でも、十分な通気性能が得られ、キャップ内を加圧・減圧することを確実に防止できる。 According to the writing instrument of the ninth aspect , even when a rapid cap attaching / detaching operation is performed, sufficient ventilation performance can be obtained, and the inside of the cap can be reliably prevented from being pressurized and depressurized.

本発明を実施するための最良の形態を説明する。 The best mode for carrying out the present invention will be described.

本発明は、前端が閉鎖され且つ後端が開口された内キャップ３と、前記内キャップ３の外面に固着され且つ少なくとも後端が開口された外キャップ４とからなるキャップ２と、前記キャップ２が着脱自在の、前端にペン先８を有する軸筒６を備えた筆記具本体５とからなり、前記キャップ２を前記軸筒６のペン先８側に装着した際、前記内キャップ３がペン先８を密封し、前記外キャップ４の内面と前記軸筒６の外面とが嵌合してなる筆記具であって、前記内キャップ３の開口端部に、後方に突出する後端筒部３１を形成し、前記後端筒部３１の外周面に環状の外向シール部３１aを形成し、前記外キャップ４の側壁に通気孔４１を貫設し、一方、前記軸筒６の前端部に、前方に突出する前端筒部６１を形成し、前記前端筒部６１の内周面に環状の内向シール部６１ａを形成し、キャップ２を軸筒６のペン先８側に装着した際、前記外向シール部３１aと前記内向シール部６１ａとが径方向に密接し、前記外向シール部３１ａと前記内向シール部６１ａとが密接状態にない場合、前記通気孔４１を介して内キャップ３内部と外キャップ４外部とが連通してなり、前記通気孔４１が、前記内キャップ３の後端筒部３１の径方向外方の外キャップ４の側壁に貫設され、前記通気孔４１が内キャップ３の開口端部近傍に位置すること（構成１）を特徴とする。 The present invention includes a cap 2 comprising an inner cap 3 having a front end closed and a rear end opened, and an outer cap 4 fixed to an outer surface of the inner cap 3 and having at least a rear end opened. And a writing instrument body 5 provided with a shaft cylinder 6 having a pen tip 8 at the front end. When the cap 2 is mounted on the pen tip 8 side of the shaft barrel 6, the inner cap 3 is attached to the pen tip. 8 is a writing instrument in which the inner surface of the outer cap 4 and the outer surface of the shaft cylinder 6 are fitted, and a rear end cylindrical portion 31 protruding rearward is formed at the opening end of the inner cap 3. formed, said annular outward facing seal portion 31a formed on the outer peripheral surface of the rear tubular portion 31, and formed through the vent hole 41 in the side wall of the outer cap 4, on the other hand, the front end portion of the barrel 6, A front end cylindrical portion 61 protruding forward is formed, and a ring is formed on the inner peripheral surface of the front end cylindrical portion 61. When the cap 2 is mounted on the pen nib 8 side of the shaft tube 6, the outward seal portion 31a and the inward seal portion 61a are in close contact with each other in the radial direction, and the outward seal portion 31a is formed. said inward when the seal portion 61a is not in close contact, the Ri Na through the inner cap 3 inside and outside the cap 4 outside communicates through a vent hole 41, said vent hole 41, after the inner cap 3 A feature is that the vent hole 41 is located in the vicinity of the opening end of the inner cap 3 and penetrates through the side wall of the outer cap 4 radially outward of the end tube portion 31 (configuration 1 ).

前記筆記具１（構成１）は、後端筒部３１の外周面に環状の外向シール部３１aを形成したことにより、キャップ装着時にペン先８が外向シール部３１aに接触することを回避できる。それにより、外向シール部３１aにインキが付着すること及び外向シール部３１aが損傷することを回避できる。また、前記筆記具１（構成１）は、前端筒部６１の内周面に環状の内向シール部６１aを形成したことにより、内向シール部６１aが外部に露出していないため、誤って内向シール部６１aを傷つけることを回避できる。その結果、外向シール部３１aと内向シール部６１aの適正な密接が可能となり、気密不良が発生するおそれがない。 The writing instrument 1 (Configuration 1 ) can prevent the pen tip 8 from coming into contact with the outward seal portion 31a when the cap is mounted by forming the annular outward seal portion 31a on the outer peripheral surface of the rear end cylindrical portion 31. Thereby, it can avoid that ink adheres to the outward seal part 31a and the outward seal part 31a is damaged. Further, the writing instrument 1 (Configuration 1 ) is formed by forming the annular inward seal portion 61a on the inner peripheral surface of the front end cylinder portion 61, so that the inward seal portion 61a is not exposed to the outside. It is possible to avoid damaging 61a. As a result, the outward seal portion 31a and the inward seal portion 61a can be properly brought into close contact with each other, and there is no possibility that an airtight defect will occur.

さらに、前記筆記具１（構成１）は、前記外キャップ４の側壁に通気孔４１を貫設し、外向シール部３１aと内向シール部６１aとが密接状態にない場合、前記通気孔４１を介して内キャップ３内部と外キャップ４外部（外気）とが連通してなることによって、急激なキャップ装着を行った場合でも、内キャップ３内部の空気が通気孔４１を通って外キャップ４外部に排出され、内キャップ３内部の空気を加圧することを十分に回避できるとともに、急激なキャップ取り外しを行った場合でも、内キャップ３内部の空気を減圧することを十分に回避できる。その結果、ペン先側よりインキが外部に漏出するおそれがない。 Moreover, the writing instrument 1 (Configuration 1), and penetrated the vent holes 41 in the side wall of the outer cap 4, when the outward facing seal portion 31a and inward facing seal portion 61a is not in close contact, through the vent holes 41 By connecting the inside of the inner cap 3 and the outside of the outer cap 4 (outside air), the air inside the inner cap 3 passes through the vent hole 41 to the outside of the outer cap 4 even when the cap is suddenly attached. While being discharged, it is possible to sufficiently avoid pressurizing the air inside the inner cap 3, and even when abrupt cap removal is performed, it is possible to sufficiently avoid depressurizing the air inside the inner cap 3. As a result, there is no risk of ink leaking from the pen tip side.

また、本発明は、前端が閉鎖され且つ後端が開口された内キャップ３と、前記内キャップ３の外面に一体に連結され、前端が閉鎖され且つ後端が開口された外キャップ４とからなるキャップ２と、前記キャップ２が着脱自在の、前端にペン先８を有する軸筒６を備えた筆記具本体５とからなり、前記キャップ２を前記軸筒６のペン先８側に装着した際、前記内キャップ３がペン先８を密封し、前記外キャップ４の内面と前記軸筒６の外面とが嵌合してなる筆記具であって、前記内キャップ３の開口端部に、後方に突出する後端筒部３１を形成し、前記後端筒部３１の外周面に環状の外向シール部３１aを形成し、前記外キャップ４の側壁に通気孔４１を貫設し、一方、前記軸筒６の前端部に、前方に突出する前端筒部６１を形成し、前記前端筒部６１の内周面に環状の内向シール部６１aを形成し、キャップ２を軸筒６のペン先８側に装着した際、前記外向シール部３１aと前記内向シール部６１aとが径方向に密接し、前記外向シール部３１aと前記内向シール部６１aとが密接状態にない場合、前記通気孔４１を介して内キャップ３内部と外キャップ４外部とが連通してなり、前記通気孔４１が、前記内キャップ３の後端筒部３１の径方向外方の外キャップ４の側壁に貫設され、前記通気孔４１が内キャップ３の開口端部近傍に位置することを特徴とすること（構成２）を特徴とする。 The present invention also includes an inner cap 3 whose front end is closed and whose rear end is opened, and an outer cap 4 which is integrally connected to the outer surface of the inner cap 3 and whose front end is closed and whose rear end is opened. When the cap 2 is mounted on the pen tip 8 side of the shaft tube 6, the cap 2 is detachable, and the writing tool body 5 is provided with a shaft tube 6 having a pen tip 8 at the front end. A writing instrument in which the inner cap 3 seals the nib 8 and the inner surface of the outer cap 4 and the outer surface of the shaft cylinder 6 are fitted to each other at the opening end of the inner cap 3 at the rear. the rear tubular portion 31 which protrudes form, an annular outward facing seal portion 31a formed on the outer peripheral surface of the rear tubular portion 31, and formed through the vent hole 41 in the side wall of the outer cap 4, on the other hand, the A front end tube portion 61 protruding forward is formed at the front end portion of the shaft tube 6, and the front end tube When an annular inward seal portion 61a is formed on the inner peripheral surface of the portion 61 and the cap 2 is mounted on the pen tip 8 side of the shaft tube 6, the outward seal portion 31a and the inward seal portion 61a are in close contact with each other in the radial direction. and, wherein the outward facing seal portion 31a and the inward facing when the seal portion 61a is not in close contact, Ri Na through the inner cap 3 inside and outside the cap 4 outside communicate through the vent holes 41, said vent hole 41 The inner cap 3 is provided in a side wall of the outer cap 4 radially outward of the rear end cylindrical portion 31 of the inner cap 3, and the vent hole 41 is positioned in the vicinity of the opening end of the inner cap 3 ( It is characterized by configuration 2 ).

前記筆記具１（構成２）は、後端筒部３１の外周面に環状の外向シール部３１aを形成したことにより、キャップ装着時にペン先８が外向シール部３１aに接触することを回避できる。それにより、外向シール部３１aにインキが付着すること及び外向シール部３１aが損傷することを回避できる。また、前記筆記具１（構成２）は、前端筒部６１の内周面に環状の内向シール部６１aを形成したことにより、内向シール部６１aが外部に露出していないため、誤って内向シール部６１aを傷つけることを回避できる。その結果、外向シール部３１aと内向シール部６１aの適正な密接が可能となり、気密不良が発生するおそれがない。 The writing instrument 1 (Configuration 2 ) can prevent the pen tip 8 from coming into contact with the outward seal portion 31a when the cap is mounted by forming the annular outward seal portion 31a on the outer peripheral surface of the rear end cylindrical portion 31. Thereby, it can avoid that ink adheres to the outward seal part 31a and the outward seal part 31a is damaged. In addition, the writing instrument 1 (Configuration 2 ) is formed by forming the annular inward seal portion 61a on the inner peripheral surface of the front end cylinder portion 61, so that the inward seal portion 61a is not exposed to the outside. It is possible to avoid damaging 61a. As a result, the outward seal portion 31a and the inward seal portion 61a can be properly brought into close contact with each other, and there is no possibility that an airtight defect will occur.

さらに、前記筆記具１（構成２）は、前記外キャップ４の側壁に通気孔４１を貫設し、外向シール部３１aと内向シール部６１aとが密接状態にない場合、前記通気孔４１を介して内キャップ３内部と外キャップ４外部（外気）とが連通してなることによって、急激なキャップ装着を行った場合でも、内キャップ３内部の空気が通気孔４１を通って外キャップ４外部に排出され、内キャップ３内部の空気を加圧することを十分に回避できるとともに、急激なキャップ取り外しを行った場合でも、内キャップ３内部の空気を減圧することを十分に回避できる。その結果、ペン先側よりインキが外部に漏出するおそれがない。 Moreover, the writing instrument 1 (Configuration 2), the pierced vent 41 in the side wall of the outer cap 4, when the outward facing seal portion 31a and inward facing seal portion 61a is not in close contact, through the vent holes 41 By connecting the inside of the inner cap 3 and the outside of the outer cap 4 (outside air), the air inside the inner cap 3 passes through the vent hole 41 to the outside of the outer cap 4 even when the cap is suddenly attached. While being discharged, it is possible to sufficiently avoid pressurizing the air inside the inner cap 3, and even when abrupt cap removal is performed, it is possible to sufficiently avoid depressurizing the air inside the inner cap 3. As a result, there is no risk of ink leaking from the pen tip side.

前記筆記具１（構成１及び２）は、急激なキャップ装着を行った際、内キャップ３の外向シール部３１aと軸筒６の内向シール部６１aとが密接する直前まで、内キャップ３内部が外気と通気孔４１を通して連通している。そのため、急激なキャップ装着を行った場合でも、内キャップ３内部の空気を加圧することを、より一層、回避できる。また、前記筆記具１（構成１及び２）は、急激なキャップ取り外しを行った際、外向シール部３１aと内向シール部６１aとが密接が解除されると即座に、通気孔４１を介して内キャップ３内部と外気とが連通する。そのため、急激なキャップ取り外しを行った場合でも、内キャップ３内部の空気が減圧されることを十分に回避できる。尚、前記通気孔４１が前記内キャップ３の後端筒部３１の径方向外方の外キャップ４の側壁に貫設されるとは、前記通気孔４１が内キャップ３の開口端部近傍に位置すること、または前記通気孔４１と前記後端筒部３１との軸方向の位置が略一致することをいう。 When the writing instrument 1 (configurations 1 and 2 ) is abruptly attached to the cap, the inside of the inner cap 3 is outside air until just before the outward seal portion 31a of the inner cap 3 and the inward seal portion 61a of the shaft tube 6 are in close contact with each other. And through the vent hole 41. Therefore, even when the cap is suddenly attached, pressurization of the air inside the inner cap 3 can be further avoided. Further, when the writing instrument 1 (Configurations 1 and 2 ) is subjected to abrupt cap removal, the inner cap is immediately inserted through the vent hole 41 when the outward seal portion 31a and the inward seal portion 61a are released from close contact with each other. 3 The inside and outside air communicate. Therefore, even when the cap is suddenly removed, it is possible to sufficiently prevent the air inside the inner cap 3 from being depressurized. Note that the vent hole 41 is provided in the side wall of the outer cap 4 radially outward of the rear end cylindrical portion 31 of the inner cap 3. The vent hole 41 is located in the vicinity of the opening end of the inner cap 3. It means that the position in the axial direction of the vent hole 41 and the rear end cylinder part 31 substantially coincides.

もし、通気孔４１が内キャップ３の後端筒部３１よりも後方に大きく離れて位置していると、急激なキャップ装着を行った場合、内キャップ３の外向シール部３１aと軸筒６の内向シール部６１aとが密接する以前に、内キャップ３内部の空気が加圧され、その加圧空気を軸筒６内に入れるおそれがある。同様に、もし、通気孔４１が内キャップ３の後端筒部３１よりも後方に大きく離れて位置していると、急激なキャップ取り外しを行った場合、内キャップ３の外向シール部３１aと軸筒６の内向シール部６１aとの密接が解除されても、完全にキャップ内から筆記具本体５が除去されるまでの過程で、内キャップ３内部の空気が減圧されるおそれがある。 If the vent hole 41 is located far behind the rear end cylindrical portion 31 of the inner cap 3, when the cap is suddenly attached, the outward seal portion 31a of the inner cap 3 and the shaft tube 6 Before the inward seal portion 61a comes into close contact, the air inside the inner cap 3 is pressurized, and the pressurized air may enter the shaft tube 6. Similarly, if the vent hole 41 is located far behind the rear end cylindrical portion 31 of the inner cap 3, when the cap is removed suddenly, the outer seal portion 31a of the inner cap 3 and the shaft Even if the close contact with the inward seal portion 61a of the cylinder 6 is released, the air inside the inner cap 3 may be decompressed in the process until the writing instrument body 5 is completely removed from the cap.

また、本発明は、前記外向シール部３１aよりも前方の内キャップ３外面に、前記軸筒６の前端筒部６１の前端が当接可能な規制壁部３２を形成したこと（構成３）を特徴とする(図１乃至図４、図７及び図８参照)。それにより、外向シール部３１aと内向シール部６１aとが密接を開始してから終了するまでの軸方向の移動長さ（即ち密接摺動長さＬ）を一定に保つことができる。 Further, in the present invention, the regulation wall portion 32 on which the front end of the front end tube portion 61 of the shaft tube 6 can contact is formed on the outer surface of the inner cap 3 in front of the outward seal portion 31a (Configuration 3 ). It is characterized (see FIGS. 1 to 4 , 7 and 8 ). Thereby, the axial movement length (that is, the close sliding length L) from when the outward seal portion 31a and the inward seal portion 61a start to close to each other can be kept constant.

また、本発明は、前記内向シール部６１aよりも後方の軸筒６内面に、前記内キャップ３の後端筒部３１の後端が当接可能な規制壁部６２を形成したこと（構成４）を特徴とする（図５乃至図６、図９乃至図１０参照）。それにより、外向シール部３１aと内向シール部６１aとが密接を開始してから終了するまでの軸方向の移動長さ（即ち密接摺動長さＬ）を一定に保つことができる。 Further, according to the present invention, a regulation wall portion 62 on which the rear end of the rear end cylinder portion 31 of the inner cap 3 can abut is formed on the inner surface of the shaft cylinder 6 behind the inward seal portion 61a (Configuration 4). (See FIGS. 5 to 6 and FIGS. 9 to 10 ). Thereby, the axial movement length (that is, the close sliding length L) from when the outward seal portion 31a and the inward seal portion 61a start to close to each other can be kept constant.

また、本発明は、前記外向シール部３１aと前記内向シール部６１aとの軸方向の密接摺動長さＬを、０．１ｍｍ〜１．０ｍｍ（好ましくは０．１ｍｍ〜０．５ｍｍ）の範囲に設定したこと（構成５）を特徴とする。それにより、外向シール部３１aと内向シール部６１aとの十分なシール性が得られ、且つ、キャップ装着時に内キャップ３内の空気を加圧することを十分に回避できるとともに、キャップ取り外し時に内キャップ３内の空気を減圧することを十分に回避できる。 In the present invention, the axially close sliding length L between the outward seal portion 31a and the inward seal portion 61a is in the range of 0.1 mm to 1.0 mm (preferably 0.1 mm to 0.5 mm). (Configuration 5 ). Thereby, sufficient sealing performance between the outward seal portion 31a and the inward seal portion 61a can be obtained, and it is possible to sufficiently avoid pressurizing the air in the inner cap 3 when the cap is attached, and the inner cap 3 when removing the cap. Depressurizing the air inside can be sufficiently avoided.

もし、前記密接摺動長さＬが、０．１ｍｍよりも小さい場合、外向シール部３１aと内向シール部６１aとの間の十分なシール性が得られず、ペン先８の密封が不完全になるおそれがある。一方、もし、前記密接摺動長さＬが、１．０ｍｍよりも大きい場合、通常のキャップ装着の際に、内キャップ３内の空気を加圧して、インキタンク内に加圧空気を入れたり、通常のキャップ取り外しの際に、内キャップ３内の空気を減圧したりするおそれがある If the close sliding length L is less than 0.1 mm, sufficient sealing performance between the outward seal portion 31a and the inward seal portion 61a cannot be obtained, and the pen tip 8 is not completely sealed. There is a risk. On the other hand, if the close sliding length L is larger than 1.0 mm, the air in the inner cap 3 is pressurized and the pressurized air is put into the ink tank when the normal cap is attached. When removing the normal cap, the air in the inner cap 3 may be depressurized.

また、本発明は、前記筆記具本体５が、ペン先８を前端に備えるインキ保溜部材７と、該インキ保溜部材７を前部に収容した軸筒６と、該軸筒６内の前記インキ保溜部材７の後方に形成したインキタンク６５とを備え、前記インキ保溜部材７が、前記インキタンク６５内の内圧上昇に応じた余剰インキを一時的に保持してなること（構成６）を特徴とする。それにより、外向シール部３１aにインキが付着すること及び外向シール部３１aが損傷することを回避でき、外向シール部３１aと内向シール部６１aの適正な密接が可能となり、気密不良が発生するおそれがない直液式筆記具を得る。しかも、急激なキャップ装着を行った場合や、急激なキャップ取り外しを行った場合でも、ペン先側よりインキが外部に漏出するおそれがない直液式筆記具を得る。 In the present invention, the writing instrument body 5 includes an ink reservoir member 7 provided with a pen tip 8 at the front end, a shaft cylinder 6 in which the ink reservoir member 7 is accommodated in the front portion, and the above-described inside of the shaft cylinder 6. An ink tank 65 formed behind the ink reservoir member 7, and the ink reservoir member 7 temporarily holds excess ink corresponding to an increase in internal pressure in the ink tank 65 (Configuration 6). ). As a result, it is possible to prevent ink from adhering to the outward seal portion 31a and damage to the outward seal portion 31a, and to allow the outward seal portion 31a and the inward seal portion 61a to be properly in close contact with each other. Get no direct liquid writing instrument. In addition, even when the cap is suddenly attached or when the cap is suddenly removed, a direct liquid writing instrument is obtained in which there is no risk of ink leaking outside from the pen tip side.

また、本発明は、前記規制壁部３２よりも後方の後端筒部３１が薄肉円筒状であること（構成７）を特徴とする。それにより、後端筒部３１の径方向の弾性変形を容易にし、後端筒部３１外周面の外向シール部３１ａと前端筒部６１内周面の内向シール部６１ａとのスムーズな密接摺動を可能にする。尚、前記後端筒部３１が薄肉であるとは、後端筒部３１が、内キャップ３の後端筒部３１よりも前方部分と比較して薄肉であることをいう。 In addition, the present invention is characterized in that the rear end cylindrical portion 31 behind the regulating wall portion 32 has a thin cylindrical shape (Configuration 7 ). Thereby, the elastic deformation in the radial direction of the rear end cylinder part 31 is facilitated, and smooth intimate sliding between the outward seal part 31a on the outer peripheral surface of the rear end cylinder part 31 and the inward seal part 61a on the inner peripheral surface of the front end cylinder part 61 is achieved. Enable. In addition, the said rear end cylinder part 31 means that the rear end cylinder part 31 is thin compared with the front part rather than the rear end cylinder part 31 of the inner cap 3. As shown in FIG.

また、本発明は、前記規制壁部６２よりも前方の前端筒部６１が薄肉円筒状であること（構成８）を特徴とする。それにより、前端筒部６１の径方向の弾性変形を容易にし、後端筒部３１外周面の外向シール部３１ａと前端筒部６１内周面の内向シール部６１ａとのスムーズな密接摺動を可能にする。尚、前記前端筒部６１が薄肉であるとは、前端筒部６１が、内キャップ３の前端筒部６１よりも後方部分と比較して薄肉であることをいう。 Further, the present invention is characterized in that the front end cylinder part 61 in front of the regulation wall part 62 is a thin cylindrical shape (Configuration 8 ). Thereby, the elastic deformation in the radial direction of the front end cylinder part 61 is facilitated, and smooth intimate sliding between the outward seal part 31a on the outer peripheral surface of the rear end cylinder part 31 and the inward seal part 61a on the inner peripheral surface of the front end cylinder part 61 is achieved. enable. In addition, the said front end cylinder part 61 means that the front end cylinder part 61 is thin compared with the back part rather than the front end cylinder part 61 of the inner cap 3. As shown in FIG.

また、本発明は、前記通気孔の総開口面積が０．５ｍｍ^２以上（好ましくは１ｍｍ^２以上、さらに好ましくは３ｍｍ^２以上）であること（構成９）を特徴とする。それにより、急激なキャップ着脱動作が行われた場合でも、十分な通気性能が得られ、キャップ内を加圧・減圧することを確実に防止できる。もし、前記通気孔の総開口面積が０．５ｍｍ^２（平方ミリメートル）未満の場合、急激なキャップの着脱動作が行われた場合、通気性能が不十分となり、内キャップ３内が加圧・減圧されるおそれがある。尚、前記通気孔４１の総開口面積とは、通気孔４１が複数の場合は、各通気孔４１の開口面積の総和をいう。 In addition, the present invention is characterized in that the total opening area of the vent holes is 0.5 mm ² or more (preferably 1 mm ² or more, more preferably 3 mm ² or more) (Configuration 9 ). Thereby, even when a rapid cap attaching / detaching operation is performed, sufficient ventilation performance is obtained, and it is possible to reliably prevent pressurization and decompression of the inside of the cap. If the total opening area of the vent holes is less than 0.5 mm ² (square millimeter), if the cap is suddenly attached / detached, the venting performance becomes insufficient, and the inside cap 3 is pressurized / depressurized. There is a risk of being. The total opening area of the vent holes 41 is the sum of the opening areas of the vent holes 41 when there are a plurality of vent holes 41.

本発明の筆記具１の実施例を図面に従って順に説明する。 Embodiments of the writing instrument 1 of the present invention will be described in order with reference to the drawings.

［第１実施例］
図１乃至図４に本発明の筆記具１の第１実施例を示す。図１は本実施例の筆記具１のキャップ装着状態を示す。図２は図１のＡ部拡大図である。図３は図１のキャップ２を示す。図４は図１の筆記具本体５のペン先８側を示す。本実施例は、キャップ２と、該キャップ２をペン先８側に着脱自在に構成した筆記具本体５とからなる。 [First embodiment]
1 to 4 show a first embodiment of the writing instrument 1 of the present invention. FIG. 1 shows a cap mounted state of the writing instrument 1 of this embodiment. FIG. 2 is an enlarged view of part A of FIG. FIG. 3 shows the cap 2 of FIG. 4 shows the pen tip 8 side of the writing instrument body 5 of FIG. The present embodiment is composed of a cap 2 and a writing instrument body 5 in which the cap 2 is detachably attached to the pen tip 8 side.

（キャップ）
本実施例のキャップ２について説明する。前記キャップ２は、内キャップ３と、該内キャップ３を内面に固着した、内キャップ３と別部品よりなる外キャップ４とからなる。 (cap)
The cap 2 of the present embodiment will be described. The cap 2 is composed of an inner cap 3 and an outer cap 4 that is fixed to the inner surface of the inner cap 3 and an outer cap 4 that is a separate part.

（内キャップ）
前記内キャップ３は、前端が閉鎖され且つ後端が開口された円筒状の有底筒体からなる。前記内キャップ３は、合成樹脂（例えばポリプロピレン）の射出成形より得られる。本実施例では、前記内キャップ３は、透明な合成樹脂により形成されるが、不透明な合成樹脂により形成されてもよい。 (Inner cap)
The inner cap 3 is formed of a cylindrical bottomed cylinder having a front end closed and a rear end opened. The inner cap 3 is obtained by injection molding of a synthetic resin (for example, polypropylene). In the present embodiment, the inner cap 3 is formed of a transparent synthetic resin, but may be formed of an opaque synthetic resin.

前記内キャップ３の外周面には、外向突起３３が環状に一体に形成される。前記外向突起３３には、軸方向に通気溝３３aが貫設される。前記通気溝３３aは、具体的には軸線に対して対称位置に２本、設けられる。 On the outer peripheral surface of the inner cap 3, outward projections 33 are integrally formed in an annular shape. The outward projection 33 is provided with a ventilation groove 33a extending in the axial direction. Specifically, two ventilation grooves 33a are provided at symmetrical positions with respect to the axis.

前記内キャップ３の開口端部には、薄肉円筒状の後端筒部３１が一体に形成される。前記後端筒部３１の外周面には環状の外向シール部３１aが一体に形成される。前記外向シール部３１aは、環状平滑面または環状突起のいずれであってもよいが、本実施例では環状平滑面が採用される。前記外向シール部３１aより前方の内キャップ３外周面（即ち後端筒部３１の基部の外周面）には、段形状の規制壁部３２が一体に形成される。即ち、前記規制壁部３２よりも後方の後端筒部３１は、薄肉円筒状に形成される。 A thin cylindrical rear end cylindrical portion 31 is integrally formed at the opening end of the inner cap 3. An annular outward seal portion 31 a is integrally formed on the outer peripheral surface of the rear end cylindrical portion 31. The outward seal portion 31a may be either an annular smooth surface or an annular protrusion, but an annular smooth surface is employed in this embodiment. On the outer peripheral surface of the inner cap 3 in front of the outward seal portion 31a (that is, the outer peripheral surface of the base portion of the rear end cylindrical portion 31), a step-shaped regulation wall portion 32 is integrally formed. That is, the rear end cylinder part 31 behind the restriction wall part 32 is formed in a thin cylindrical shape.

また、前記規制壁部３２の径方向内方（即ち後端筒部３１と規制壁部３２との接続部分）には、環状凹部３４が形成される。それにより、成形後の軸筒６の前端筒部６１の前端内周縁にバリが突出していても、キャップ装着時、前記バリを環状凹部３４に収容し、前記バリと内キャップ３外面との接触を回避し、規制壁部３２と前端筒部６１の前端との適正な当接を可能にする。 An annular recess 34 is formed on the inner side in the radial direction of the restriction wall portion 32 (that is, the connection portion between the rear end cylindrical portion 31 and the restriction wall portion 32). Thereby, even if a burr protrudes from the inner peripheral edge of the front end of the front end cylinder part 61 of the shaft cylinder 6 after molding, the burr is accommodated in the annular recess 34 when the cap is mounted, and the burr and the inner cap 3 are in contact with each other. This makes it possible to properly contact the restriction wall portion 32 and the front end of the front end cylindrical portion 61.

（外キャップ）
前記外キャップ４は、前端が閉鎖され且つ後端が開口された円筒状の有底筒体からなる。前記外キャップ４は、合成樹脂（例えばポリカーボネイト）の射出成形より得られる。前記外キャップ４の内周面には、環状の内向突起４２が一体に形成される。本実施例では、前記外キャップ４は、透明な合成樹脂により形成されるが、不透明な合成樹脂により形成されてもよい。 (Outer cap)
The outer cap 4 is formed of a cylindrical bottomed cylindrical body whose front end is closed and whose rear end is opened. The outer cap 4 is obtained by injection molding of a synthetic resin (for example, polycarbonate). An annular inward projection 42 is integrally formed on the inner peripheral surface of the outer cap 4. In the present embodiment, the outer cap 4 is formed of a transparent synthetic resin, but may be formed of an opaque synthetic resin.

前記外キャップ４内部に内キャップ３を固着する際、前記内キャップ３を外キャップ４内に挿入し、前記外キャップ４の内向突起４２を前記内キャップ３の外向突起３３と乗り越え嵌合させると同時に、内キャップ３の頂壁外面を外キャップ４の頂壁内面と前後に当接させる。それにより、内キャップ３の外面と外キャップ４の内面とが、前後のがたつきなく固着される。また、前記内キャップ３外面の外向突起３３の通気溝３３aにより、内キャップ３外面と外キャップ４内面との間に前後の空気流通可能な隙間が形成される。 When the inner cap 3 is fixed inside the outer cap 4, the inner cap 3 is inserted into the outer cap 4, and the inward projection 42 of the outer cap 4 is fitted over the outer projection 33 of the inner cap 3. At the same time, the outer surface of the top wall of the inner cap 3 is brought into contact with the inner surface of the top wall of the outer cap 4 in the front-rear direction. Thereby, the outer surface of the inner cap 3 and the inner surface of the outer cap 4 are firmly fixed without back and forth rattling. Further, a front and rear air flow gap is formed between the outer surface of the inner cap 3 and the inner surface of the outer cap 4 by the ventilation groove 33a of the outward projection 33 on the outer surface of the inner cap 3.

前記外キャップ４の側壁には通気孔４１が径方向に貫設される。前記通気孔４１は、後端筒部３１の径方向外方（即ち内キャップ３の開口端部近傍）に位置している。前記通気孔４１の大きさ及び個数は、十分な空気流通路が確保できるよう適宜設定される。本実施例では、前記通気孔４１は、軸線と対称位置の２箇所に形成される。また、前記通気孔４１の形状は、円、楕円、多角形等いずれであってもよい。また、本実施例では、各通気孔の開口面積が１．７７ｍｍ^２のものが２個であるため、前記通気孔４１の総開口面積が、３．５４ｍｍ^２に設定される。即ち、前記通気孔４１の総開口面積が、０．５ｍｍ^２以上である。それにより、急激なキャップ着脱動作が行われた場合でも、十分な通気性能が得られ、内キャップ３内を加圧及び減圧することを確実に防止できる。 A vent hole 41 is formed through the side wall of the outer cap 4 in the radial direction. The vent hole 41 is located radially outward of the rear end cylinder portion 31 (that is, near the opening end portion of the inner cap 3). The size and number of the vent holes 41 are appropriately set so that a sufficient air flow passage can be secured. In this embodiment, the vent holes 41 are formed at two positions symmetrical to the axis. The shape of the vent hole 41 may be any of a circle, an ellipse, a polygon, and the like. Further, in this embodiment, since there are two air holes having an opening area of 1.77 mm ² , the total opening area of the air holes 41 is set to 3.54 mm ² . That is, the total opening area of the vent holes 41 is 0.5 mm ² or more. Thereby, even when a rapid cap attaching / detaching operation is performed, sufficient ventilation performance is obtained, and it is possible to reliably prevent the inside cap 3 from being pressurized and depressurized.

また、前記通気孔４１より後方の外キャップ４の内面には、嵌合用突起４３が一体に形成される。前記外キャップ４内面の嵌合用突起４３は、キャップ装着時、軸筒６外面の嵌合用突起６４と乗り越え嵌合する。前記嵌合用突起４３及び嵌合用突起６４は、一方が環状突起であり、他方が複数個が周状に分散された点状突起である構成が好ましく、それにより、急激なキャップの着脱操作が行われても、嵌合用突起４３と嵌合用突起６４との間に通気路が形成され、外キャップ４内面と軸筒６外面との間の空気の加圧及び減圧を、一層回避できる。これ以外にも、前記嵌合用突起４３及び嵌合用突起６４は、両者が環状突起よりなる構成であってもよい。 A fitting projection 43 is integrally formed on the inner surface of the outer cap 4 behind the vent hole 41. The fitting protrusion 43 on the inner surface of the outer cap 4 is fitted over the fitting protrusion 64 on the outer surface of the shaft tube 6 when the cap is mounted. It is preferable that one of the fitting protrusion 43 and the fitting protrusion 64 is an annular protrusion, and the other is a point-like protrusion in which a plurality of the protrusions are circumferentially dispersed. Even if this is done, an air passage is formed between the fitting projection 43 and the fitting projection 64, and pressurization and decompression of air between the inner surface of the outer cap 4 and the outer surface of the shaft tube 6 can be further avoided. In addition to this, the fitting protrusion 43 and the fitting protrusion 64 may be configured by both annular protrusions.

（筆記具本体）
次に、本実施例の筆記具本体５について説明する。本実施例の筆記具本体５は、前端が開口された円筒状の軸筒６と、該軸筒６の前端開口部の内面に嵌入される複数の櫛歯７１からなるインキ保溜部材７と、該インキ保溜部材７の前端に保持されるペン先８と、該ペン先８と接続され該インキ保溜部材７の軸心孔に挿着されるインキ誘導芯９とを備える。 (Writing instrument body)
Next, the writing instrument body 5 of the present embodiment will be described. The writing instrument main body 5 of the present embodiment includes a cylindrical shaft cylinder 6 having a front end opened, and an ink storage member 7 including a plurality of comb teeth 71 fitted into the inner surface of the front end opening of the shaft cylinder 6; A pen tip 8 held at the front end of the ink reservoir member 7 and an ink guide core 9 connected to the pen tip 8 and inserted into the axial hole of the ink reservoir member 7 are provided.

前記軸筒６は、合成樹脂（例えばポリプロピレン）の射出成形により得られる。前記軸筒６内のインキ保溜部材７の後方には、インキを直に貯留するためのインキタンク６５が、軸筒６と一体に構成されるか、または軸筒６に着脱自在に取り付けられるカートリッジ容器により構成される。前記軸筒６の開口端部には、薄肉円筒状の前端筒部６１が一体に形成される。前記前端筒部６１の内周面には環状の内向シール部６１aが一体に形成される。前記内向シール部６１aは、環状平滑面または環状突起のいずれであってもよいが、本実施例では環状平滑面が採用される。 The shaft cylinder 6 is obtained by injection molding of a synthetic resin (for example, polypropylene). An ink tank 65 for directly storing ink is formed integrally with the shaft tube 6 or attached to the shaft tube 6 in a detachable manner behind the ink storage member 7 in the shaft tube 6. Consists of a cartridge container. A thin cylindrical front end tube portion 61 is integrally formed at the opening end portion of the shaft tube 6. An annular inward seal portion 61 a is integrally formed on the inner peripheral surface of the front end cylinder portion 61. The inward seal portion 61a may be either an annular smooth surface or an annular protrusion, but an annular smooth surface is employed in this embodiment.

前記前端筒部６１（内向シール部６１a）よりも後方の軸筒６の内周面には、環状の抜け止め突起６３が一体に形成される。前記抜け止め突起６３は、インキ保溜部材７の他の櫛歯７１より大きい外径を有する支持用櫛歯７１aと乗り越え嵌合して、インキ保溜部材７の脱落を防止する。前記抜け止め突起６３よりも前方の軸筒６の開口端部は、インキ保溜部材７と非接触状態にあるため、インキ保溜部材７の嵌入が、内向シール部６１aの内径寸法に影響を与えない。 An annular retaining protrusion 63 is integrally formed on the inner peripheral surface of the shaft tube 6 behind the front end tube portion 61 (inward seal portion 61a). The retaining protrusion 63 is fitted over the supporting comb teeth 71 a having an outer diameter larger than that of the other comb teeth 71 of the ink retaining member 7 to prevent the ink retaining member 7 from falling off. Since the opening end portion of the shaft cylinder 6 in front of the retaining protrusion 63 is not in contact with the ink reservoir member 7, the insertion of the ink reservoir member 7 affects the inner diameter of the inward seal portion 61a. Don't give.

前記インキ保溜部材７は、合成樹脂（例えば、ＡＢＳ樹脂）の射出成形により得られる。前記インキ保溜部材７は、インキタンク６５内の圧力上昇に応じた溢出インキを一時的に保持する部材である。前記インキ保溜部材７は、複数の円板状の櫛歯７１と、前記櫛歯７１間に形成したインキ保溜溝７２と、前記複数の櫛歯７１に軸方向に貫設されたインキ誘導スリット７３と、前記櫛歯７１に形成された切り欠き状の空気溝７４とを備える。また、インキ保溜部材７の軸心には軸心孔が貫設され、前記軸心孔にインキ誘導芯９（例えば、合成樹脂押出成形体または繊維束樹脂加工体）が挿着される。また、前記インキ保溜部材７の前端部には、ペン先８（例えば、先端にスリットを備えた金属板の折り曲げ加工体よりなる万年筆状のペン先）が取り付けられる。前記インキ誘導芯９の前端は、前記ペン先８と接続され、前記インキ誘導芯９の後端は、インキタンク６５内に接続される。 The ink reservoir member 7 is obtained by injection molding of a synthetic resin (for example, ABS resin). The ink reservoir member 7 is a member that temporarily holds overflow ink in response to a pressure increase in the ink tank 65. The ink retaining member 7 includes a plurality of disc-shaped comb teeth 71, an ink retaining groove 72 formed between the comb teeth 71, and an ink guide penetrating the plurality of comb teeth 71 in the axial direction. A slit 73 and a notched air groove 74 formed in the comb tooth 71 are provided. In addition, an axial hole is formed through the shaft center of the ink retaining member 7, and an ink guide core 9 (for example, a synthetic resin extruded body or a fiber bundle resin processed body) is inserted into the axial hole. Further, a pen tip 8 (for example, a fountain pen-like pen tip made of a bent metal plate body provided with a slit at the tip) is attached to the front end portion of the ink storage member 7. The front end of the ink guide core 9 is connected to the pen tip 8, and the rear end of the ink guide core 9 is connected to the ink tank 65.

（本実施例の作用）
本実施例において、キャップ２を筆記具本体５のペン先８側に装着した場合、図１及び図２に示すように、内キャップ３の外向シール部３１aと軸筒６の内向シール部６１aとが径方向に密接(即ち気密嵌合)するとともに、内キャップ３の規制壁部３２に軸筒６の前端筒部６１の前端が軸方向に当接し、さらに、外キャップ４内面の嵌合用突起４３と軸筒６外面の嵌合用突起６４とが乗り越え嵌合する。 (Operation of this embodiment)
In this embodiment, when the cap 2 is mounted on the pen tip 8 side of the writing instrument body 5, as shown in FIGS. 1 and 2, the outward seal portion 31a of the inner cap 3 and the inward seal portion 61a of the shaft tube 6 are provided. The front end of the front end tube portion 61 of the shaft tube 6 abuts in the axial direction on the regulating wall portion 32 of the inner cap 3 and the fitting projection 43 on the inner surface of the outer cap 4 is further provided. And the fitting protrusion 64 on the outer surface of the shaft tube 6 are fitted over.

また、キャップ装着過程において、外向シール部３１aと内向シール部６１aとが密接する直前まで、通気孔４１を介して内キャップ３内部と外気とが十分に連通している。そのため、急激なキャップ装着を行ったとしても、内キャップ３内部の空気が加圧されることを十分に回避できる。また、キャップ取り外し過程において、外向シール部３１aと内向シール部６１aとが密接が解除されると即座に、通気孔４１を介して内キャップ３内部と外気とが連通する。そのため、急激なキャップ取り外しを行ったとしても、内キャップ３内部の空気が減圧されることを十分に回避できる。 Further, in the cap mounting process, the inside of the inner cap 3 and the outside air are sufficiently communicated with each other through the vent hole 41 until immediately before the outward seal portion 31a and the inward seal portion 61a are in close contact with each other. Therefore, even if the cap is suddenly attached, it is possible to sufficiently prevent the air inside the inner cap 3 from being pressurized. Further, in the cap removal process, when the outward seal portion 31 a and the inward seal portion 61 a are released from close contact with each other, the inside of the inner cap 3 communicates with the outside air through the vent hole 41. Therefore, even if the cap is removed suddenly, it is possible to sufficiently prevent the air inside the inner cap 3 from being depressurized.

また、本実施例は、キャップ装着時のキャップ２内の外向シール部３１a（気密シール部）にペン先８が接触することを回避でき、それにより、外向シール部３１aの損傷及び外向シール部３１aへのインキ付着を回避でき、しかも、軸筒６の内向シール部６１a（気密シール部）が、外部に露出していないため、誤って内向シール部６１aに接触して内向シール部６１aを傷つけることを回避できる。 Further, in this embodiment, it is possible to prevent the pen tip 8 from coming into contact with the outward seal portion 31a (airtight seal portion) in the cap 2 when the cap is mounted, thereby damaging the outward seal portion 31a and the outward seal portion 31a. Ink sticking to the ink can be avoided, and the inward seal portion 61a (airtight seal portion) of the shaft tube 6 is not exposed to the outside, so that the inward seal portion 61a is accidentally contacted and damaged. Can be avoided.

前記外向シール部３１aと前記内向シール部６１aとの軸方向の密接摺動長さＬ(即ち、外向シール部３１aと内向シール部６１aとが密接を開始してから終了するまでの軸方向の密接摺動長さＬ)は、０．１ｍｍ〜１．０ｍｍ（好ましくは、０．１ｍｍ〜０．５ｍｍ)の範囲が好ましい。それにより、外向シール部３１aと内向シール部６１aとの十分なシール性が得られ、且つ、キャップ装着時に内キャップ３内の空気を加圧することを十分に回避できるとともに、キャップ取り外し時に内キャップ３内の空気を減圧することを十分に回避できる。 A close sliding length L in the axial direction between the outward seal portion 31a and the inward seal portion 61a (that is, close contact in the axial direction from the start of close contact between the outward seal portion 31a and the inward seal portion 61a to the end thereof). The sliding length L) is preferably in the range of 0.1 mm to 1.0 mm (preferably 0.1 mm to 0.5 mm). Thereby, sufficient sealing performance between the outward seal portion 31a and the inward seal portion 61a can be obtained, and it is possible to sufficiently avoid pressurizing the air in the inner cap 3 when the cap is attached, and the inner cap 3 when removing the cap. Depressurizing the air inside can be sufficiently avoided.

もし、前記密接摺動長さＬが、０．１ｍｍより小さい場合、外向シール部３１aと内向シール部６１aとの間の十分なシール性が得られず、ペン先８の密封が不完全になるおそれがある。一方、もし、前記密接摺動長さＬが、１．０ｍｍより大きい場合、キャップ装着の際、内キャップ３内の空気を加圧して、インキタンク６５内に加圧空気を入れたり、キャップ取り外しの際、内キャップ３内の空気を減圧するおそれがある。尚、本実施例では、密接摺動長さＬを、０．３ｍｍに設定している。 If the close sliding length L is less than 0.1 mm, sufficient sealing performance between the outward seal portion 31a and the inward seal portion 61a cannot be obtained, and the pen tip 8 is not completely sealed. There is a fear. On the other hand, if the close sliding length L is larger than 1.0 mm, when the cap is attached, the air in the inner cap 3 is pressurized and pressurized air is put into the ink tank 65 or the cap is removed. At this time, the air in the inner cap 3 may be decompressed. In this embodiment, the close sliding length L is set to 0.3 mm.

［第２実施例］
図５及び図６に本発明の第２実施例を示す。
本実施例は、前端筒部６１の内向シール部６１aの後方の軸筒６内面に、段形状の規制壁部６２が一体に形成される。キャップ装着時、内キャップ３の外向シール部３１aと軸筒６の内向シール部６１aとが径方向に密接すると同時に、内キャップ３の後端筒部３１の後端が前記規制壁部６２と軸方向に当接される。前記規制壁部６２よりも前方の前端筒部６１は薄肉円筒状に形成される。尚、本実施例の他の構成及び作用は、第１実施例と同様であるため、説明を省略する。 [ Second Embodiment]
5 and 6 show a second embodiment of the present invention.
In the present embodiment, a step-shaped regulation wall 62 is integrally formed on the inner surface of the shaft tube 6 behind the inward seal portion 61a of the front end tube portion 61. When the cap is mounted, the outward seal portion 31a of the inner cap 3 and the inward seal portion 61a of the shaft tube 6 are in close contact with each other in the radial direction, and at the same time, the rear end tube portion 31 of the inner cap 3 is connected to the regulation wall portion 62 and the shaft. Abutted in the direction. The front end cylinder part 61 ahead of the regulation wall part 62 is formed in a thin cylindrical shape. In addition, since the other structure and effect | action of a present Example are the same as that of 1st Example, description is abbreviate | omitted.

［第３実施例］
図７及び図８に本発明の第４実施例を示す。
本実施例では、キャップ２は、合成樹脂(例えばポリプロピレン)の射出成形により得られ、内キャップ３外面と外キャップ４内面とが環状の連結壁部２１により一体に連結される。前記内キャップ３及び前記外キャップ４は、前端が閉鎖され且つ後端が開口された円筒状の有底筒体からなる。即ち、本実施例では、キャップ２が内キャップ３と外キャップ４とが一体に形成され、キャップ２が一部品よりなるものであるのに対し、前記第１実施例及び第２実施例では、キャップ２が内キャップ３と外キャップ4の二部品からなる。尚、本実施例の他の構成及び作用は、第１実施例と同様であるため、説明を省略する。 [ Third embodiment]
7 and 8 show a fourth embodiment of the present invention.
In the present embodiment, the cap 2 is obtained by injection molding of a synthetic resin (for example, polypropylene), and the outer surface of the inner cap 3 and the inner surface of the outer cap 4 are integrally connected by an annular connecting wall portion 21. The inner cap 3 and the outer cap 4 are formed of a cylindrical bottomed cylindrical body whose front end is closed and whose rear end is opened. That is, in the present embodiment, the cap 2 is formed integrally with the inner cap 3 and the outer cap 4, and the cap 2 is composed of one component, whereas in the first and second embodiments, The cap 2 consists of two parts, an inner cap 3 and an outer cap 4. In addition, since the other structure and effect | action of a present Example are the same as that of 1st Example, description is abbreviate | omitted.

［第４実施例］
図９及び図１０に本発明の第４実施例を示す。
本実施例では、第３実施例同様、キャップ２は、合成樹脂(例えばポリプロピレン)の射出成形により得られ、内キャップ３外面と外キャップ４内面とが環状の連結壁部２１により一体に連結される。前記内キャップ３及び前記外キャップ４は、前端が閉鎖され且つ後端が開口された円筒状の有底筒体からなる。本実施例は、第２実施例同様、前端筒部６１の内向シール部６１aの後方の軸筒６内面に、段形状の規制壁部６２が一体に形成される。キャップ装着時、内キャップ３の外向シール部３１aと軸筒６の内向シール部６１aとが径方向に密接すると同時に、内キャップ３の後端筒部３１の後端が前記規制壁部６２と軸方向に当接される。尚、本実施例の他の構成及び作用は、第１実施例及び第２実施例と同様であるため、説明を省略する。 [ Fourth embodiment]
9 and 10 show a fourth embodiment of the present invention.
In this embodiment, as in the third embodiment, the cap 2 is obtained by injection molding of a synthetic resin (for example, polypropylene), and the outer surface of the inner cap 3 and the inner surface of the outer cap 4 are integrally connected by an annular connecting wall portion 21. The The inner cap 3 and the outer cap 4 are formed of a cylindrical bottomed cylindrical body whose front end is closed and whose rear end is opened. In this embodiment, like the second embodiment, a step-shaped regulating wall portion 62 is integrally formed on the inner surface of the shaft tube 6 behind the inward seal portion 61a of the front end tube portion 61. When the cap is mounted, the outward seal portion 31a of the inner cap 3 and the inward seal portion 61a of the shaft tube 6 are in close contact with each other in the radial direction, and at the same time, the rear end tube portion 31 of the inner cap 3 is connected to the regulation wall portion 62 and the shaft. Abutted in the direction. In addition, since the other structure and effect | action of a present Example are the same as that of 1st Example and 2nd Example, description is abbreviate | omitted.

尚、本発明で、軸筒６とは、ペン先８を保持し且つ軸筒６の前端開口部に取り付けられるペン先ホルダーを含む。また、本発明で、ペン先８は、前記実施例以外にも、ボールペンチップ、繊維ペン体、多孔質ペン体、合成樹脂押出成形によるプラスチックペン体、毛筆ペン体等いずれであってもよい。また、本発明で、筆記具本体５のタイプは、前記実施例の、軸筒６内部に直にインキを貯溜する直液式の他にも、繊維加工体等よりなるインキ吸蔵体にインキを含浸保持させる構成（いわゆる中綿式）でもよい。また、本発明で、外キャップ４は、本実施例のような一端が閉鎖されるタイプの他、両端が開口されるタイプでもよい。また、第１実施例、第２実施例、第３実施例及び第４実施例において、外キャップ４の外面にクリップを設けてもよい。 In the present invention, the shaft tube 6 includes a pen tip holder that holds the pen tip 8 and is attached to the front end opening of the shaft tube 6. Further, in the present invention, the pen tip 8 may be any of a ballpoint pen tip, a fiber pen body, a porous pen body, a plastic pen body by synthetic resin extrusion molding, a brush pen body, etc. in addition to the above embodiments. In the present invention, the type of the writing instrument body 5 is impregnated with ink in an ink occlusion body such as a fiber processed body in addition to the direct liquid type in which the ink is directly stored in the shaft cylinder 6 of the above embodiment. The structure to hold (so-called batting type) may be used. Further, in the present invention, the outer cap 4 may be of a type in which both ends are opened as well as a type in which one end is closed as in the present embodiment. The first embodiment, second embodiment, in the third and fourth embodiments may be provided with a click-liter up to the outer surface of the outer cap 4.

本発明の第１実施例のキャップ装着状態を示す要部縦断面図である。It is a principal part longitudinal cross-sectional view which shows the cap mounting state of 1st Example of this invention. 図１のＡ部拡大図である。It is the A section enlarged view of FIG. 図１のキャップの縦断面図である。It is a longitudinal cross-sectional view of the cap of FIG. 図１の筆記具本体の縦断面図である。It is a longitudinal cross-sectional view of the writing instrument main body of FIG. 本発明の第２実施例のキャップ装着状態を示す要部縦断面図である。It is a principal part longitudinal cross-sectional view which shows the cap mounting state of 2nd Example of this invention. 図５のＢ部拡大図である。It is the B section enlarged view of FIG. 本発明の第３実施例のキャップ装着状態を示す要部縦断面図である。It is a principal part longitudinal cross-sectional view which shows the cap mounting state of 3rd Example of this invention. 図７のＣ部拡大図である。It is the C section enlarged view of FIG. 本発明の第４実施例のキャップ装着状態を示す要部縦断面図である。It is a principal part longitudinal cross-sectional view which shows the cap mounting state of 4th Example of this invention. 図９のＤ部拡大図である。It is the D section enlarged view of FIG.

１筆記具
２キャップ
２１連結壁部
３内キャップ
３１後端筒部
３１a 外向シール部
３２規制壁部
３３外向突起
３３a 通気溝
３４環状凹部
４外キャップ
４１通気孔
４２内向突起
４３嵌合用突起
５筆記具本体
６軸筒
６１前端筒部
６１a 内向シール部
６２規制壁部
６３抜け止め突起
６４嵌合用突起
６５インキタンク
７インキ保溜部材
７１櫛歯
７１a 支持用櫛歯
７２インキ保溜溝
７３インキ誘導スリット
７４空気溝
８ペン先
９インキ誘導芯
Ｌ密接摺動長さ DESCRIPTION OF SYMBOLS 1 Writing instrument 2 Cap 21 Connection wall part 3 Inner cap 31 Rear end cylinder part 31a Outward seal part 32 Restriction wall part 33 Outward protrusion 33a Ventilation groove 34 Annular recess 4 Outer cap 41 Vent hole 42 Inward protrusion 43 Fitting protrusion 5 Writing instrument body 6 Shaft cylinder 61 Front end cylinder part 61a Inward seal part 62 Restriction wall part 63 Retaining protrusion 64 Fitting protrusion 65 Ink tank 7 Ink storage member 71 Comb tooth 71a Supporting comb tooth 72 Ink storage groove 73 Ink guide slit 74 Air groove 8 Nib 9 Ink guide core L Close sliding length

Claims

A cap comprising an inner cap having a closed front end and an open rear end; and an outer cap fixed to the outer surface of the inner cap and having at least a rear end opened; A writing instrument body having a shaft cylinder, and when the cap is mounted on the pen tip side of the shaft cylinder, the inner cap seals the pen tip, and the inner surface of the outer cap and the outer surface of the shaft cylinder, Is a writing instrument formed by fitting,
A rear end cylindrical portion protruding rearward is formed at the opening end portion of the inner cap, an annular outward seal portion is formed on the outer peripheral surface of the rear end cylindrical portion, and a vent hole is provided in the side wall of the outer cap. On the other hand, a front end tube portion protruding forward is formed at the front end portion of the shaft tube, an annular inward seal portion is formed on the inner peripheral surface of the front end tube portion, and the cap is placed on the pen tip side of the shaft tube. When the outer seal portion and the inward seal portion are in close contact with each other in the radial direction when mounted, and the outer seal portion and the inward seal portion are not in close contact with each other, the inner cap and the outer cap are interposed via the vent holes. The vent hole communicates with the outside, the vent hole penetrates the side wall of the outer cap in the radial direction of the rear end cylindrical portion of the inner cap, and the vent hole is positioned near the opening end of the inner cap. Writing instrument characterized by that.

A cap comprising an inner cap having a closed front end and an open rear end; and an outer cap integrally connected to the outer surface of the inner cap, the front end being closed and the rear end being opened; and the cap is detachable A writing instrument main body having a shaft cylinder having a pen tip at the front end, and when the cap is mounted on the pen tip side of the shaft tube, the inner cap seals the pen tip, and the inner surface of the outer cap A writing instrument formed by fitting the outer surface of the shaft cylinder,
A rear end cylindrical portion protruding rearward is formed at the opening end portion of the inner cap, an annular outward seal portion is formed on the outer peripheral surface of the rear end cylindrical portion, and a vent hole is provided in the side wall of the outer cap. On the other hand, a front end tube portion protruding forward is formed at the front end portion of the shaft tube, an annular inward seal portion is formed on the inner peripheral surface of the front end tube portion, and the cap is placed on the pen tip side of the shaft tube. When the outer seal portion and the inward seal portion are in close contact with each other in the radial direction when mounted, and the outer seal portion and the inward seal portion are not in close contact with each other, the inner cap and the outer cap are interposed via the vent holes. The vent hole communicates with the outside, the vent hole penetrates the side wall of the outer cap in the radial direction of the rear end cylindrical portion of the inner cap, and the vent hole is positioned near the opening end of the inner cap. Writing instrument characterized by that.

The writing instrument according to claim 1 or 2, wherein a regulating wall portion capable of contacting a front end of a front end cylinder portion of the shaft cylinder is formed on an outer surface of the inner cap in front of the outward seal portion .

The writing instrument according to claim 1 or 2, wherein a regulating wall portion on which a rear end of the rear end cylinder portion of the inner cap can abut is formed on the inner surface of the shaft cylinder behind the inward seal portion .

The writing instrument according to any one of claims 1 to 4, wherein a close sliding length in an axial direction between the outward seal portion and the inward seal portion is set in a range of 0.1 mm to 1.0 mm .

The writing instrument body includes an ink reservoir member having a nib at the front end, a shaft cylinder that houses the ink reservoir member in a front portion, and an ink tank that is formed behind the ink reservoir member in the shaft cylinder; 6. The writing instrument according to claim 1, wherein the ink storage member temporarily holds excess ink corresponding to an increase in internal pressure in the ink tank .

The writing instrument according to claim 3, wherein a rear end cylinder part behind the regulation wall part is a thin cylindrical shape .

The writing instrument according to claim 4, wherein the front end cylinder part in front of the restriction wall part is a thin cylindrical shape .

The writing instrument according to any one of claims 1 to 8 , wherein a total opening area of the air holes is 0.5 mm ² or more .