JP2010006055A - Writing utensil and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a writing utensil which can securely prevent a plug body from being left out to the rear part of a barrel and also, a projecting member from likewise being left out to the rear part of the barrel. <P>SOLUTION: This writing utensil is structured of a writing utensil body 2 with a pen point 21 which can store an ink internally and discharge the ink, disposed at the forward end, and the rear end part of the writing utensil body 2 is constituted of a cylindrical tube 4. The cylindrical tube 4 has an inner hole opened through in the forward and backward directions, as well as a forward end opening 41 and a rear end opening 42 which communicate with the inner hole. The plug body 5 is forced in and anchored to the inner surface of the cylinder tube 4, and the internal breathing of the cylindrical tube 4 between the forward end opening 41 and the rear end opening 42, is stopped by the plug body 5. Next, the ink is accommodated in the cylindrical tube 4 located forward of the plug body 5. Further, an internal sealing part 43 which is airtightly fitted to the outer surface of the plug body 5, is formed on the inner surface of the cydrindrical tube 4. Besides, regulating wall part 44 which comes into contact with the rear face of the plug body 5 in the forward and backward directions and checks the movement of the plug body 5 to the rear, is formed in one piece, on the inner surface of the cylindrical tube 4 located at the rear of the inner sealing part 43. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a writing instrument. Specifically, the writing tool main body comprises a cylindrical body at the rear end thereof, a stopper is press-fitted and fixed to the inner surface of the cylinder, and ink is stored inside the cylinder in front of the stopper, and the manufacturing thereof. Regarding the method.

Conventionally, Patent Document 1 discloses a configuration in which a tail plug (corresponding to a plug body of the present application) is fitted to a rear end opening of a shaft cylinder, and the rear end opening of the shaft cylinder is closed. Further, Patent Document 1 discloses a configuration in which a fitting protrusion on the inner surface of the rear end opening of the shaft cylinder and a fitting protrusion on the outer surface of the tail plug are fitted and fitted.

Further, Patent Document 2 discloses a configuration in which a tail crown (corresponding to a protruding member of the present application) is fitted into a recess provided at the rear end of the shaft cylinder, specifically, an inward projection on the inner peripheral surface of the recess. A configuration is disclosed in which the outward projection on the outer peripheral surface of the tail crown gets over and fits.

Japanese Utility Model Publication No. 63-23179 Utility Model Registration No. 2607568

In the writing instrument of Patent Document 1, when the shaft cylinder is obtained by injection molding of a synthetic resin, the fitting protrusion on the inner surface of the shaft cylinder becomes an undercut portion at the time of mold release and cannot be protruded too much. Therefore, depending on manufacturing variations, there is a weak fitting force between the tail plug and the shaft tube, and the fitting force is reduced due to creep deformation of the fitting protrusion on the inner surface of the shaft tube over time, and the tail plug is moved backward. Dropout is likely to occur.

In the writing instrument of Patent Document 2, as described above, when the shaft tube is obtained by injection molding of synthetic resin, the inward projection on the inner surface of the shaft tube becomes an undercut portion at the time of mold release and protrudes too much. I can't. For this reason, depending on manufacturing variations, there are cases where the fitting force between the tail cap and the shaft tube is weak, and the fitting force is reduced due to creep deformation of the inward projection on the inner surface of the shaft tube, causing the tail crown to fall backward. Is likely to occur.

The present invention solves the above-mentioned conventional problems, and can reliably prevent the plug body from falling off the rear of the shaft tube, and reliably prevent the projecting member from falling off the rear of the shaft tube. An object of the present invention is to provide a writing instrument that can be prevented and a method for manufacturing the writing instrument. In the present invention, in the cylindrical body, “front” refers to the pen tip side, and “rear” refers to the opposite side.

[1] The first invention of the present application is composed of a writing instrument body 2 having a pen tip 21 at the front end in which ink is accommodated and can discharge the ink, and the rear end portion of the writing instrument body 2 is formed as a cylinder 4. The cylindrical body 4 includes an inner hole penetrating in the front-rear direction, a front end opening 41 and a rear end opening 42 communicating with the inner hole, and the plug body 5 is provided on the inner surface of the cylindrical body 4. It is press-fitted and fixed, the ventilation inside the cylinder 4 between the front end opening 41 and the rear end opening 42 is blocked by the plug 5, and ink is accommodated inside the cylinder 4 in front of the plug 5. An inner seal portion 43 that is airtightly fitted to the outer surface of the plug body 5 is formed on the inner surface of the cylinder body 4 on the writing instrument, and the rear surface of the plug body 5 and the front and rear sides are formed on the inner surface of the cylinder body 4 behind the inner seal section 43. It is a requirement that the regulating wall portion 44 that contacts the direction and prevents the rearward movement of the plug body 5 is integrally formed. (Corresponding to FIGS. 1 to 7)

In the writing instrument 1 of the first invention, an inner seal portion 43 is formed on the inner surface of the cylindrical body 4 so as to be airtightly fitted to the outer surface of the plug body 5, and the plug is formed on the inner surface of the cylindrical body 4 behind the inner seal portion 43. By integrally forming a regulating wall portion 44 that abuts the rear surface of the body 5 in the front-rear direction and prevents the plug body 5 from moving backward, the plug body 5 is reliably prevented from falling off the shaft cylinder. As a result, the hermetic fitting between the inner surface of the plug 5 and the outer surface of the cylinder 4 can be maintained for a long time.

In the first aspect of the invention, the configuration in which the ink is accommodated in the cylindrical body 4 is, for example, a configuration in which the ink is directly stored in the cylindrical body 4 (so-called direct liquid type), or an ink occlusion impregnated with ink. The structure (what is called batting type) which accommodates a body in the cylinder 4 is mentioned.

[2] A second invention of the present application is the writing instrument according to the first invention, wherein an inner diameter of the inner surface of the cylindrical body 4 in front of the inner seal portion 43 is formed larger than an inner diameter C of the inner seal portion 43, It is a requirement that the inner diameter D of the regulation wall portion 44 is smaller than the inner diameter C of the inner seal portion 43. (Corresponding to FIGS. 1 to 7)

In the writing instrument 1 of the second invention, the inner diameter of the inner surface of the cylindrical body 4 in front of the inner seal portion 43 is larger than the inner diameter C of the inner seal portion 43 (that is, from the front end of the cylindrical body 4 to the inner seal portion. The inner seal portion 43 has the smallest inner diameter in the inner diameter of the cylinder 4 up to 43), whereby the plug body 5 can be smoothly inserted into the cylinder 4 from the front end opening 41 of the cylinder 4, and the inner seal An appropriate airtight fit between the portion 43 and the outer surface of the plug body 5 is obtained. Moreover, since the writing instrument 1 of the second invention can insert the plug 5 into the cylinder 4 from the front end opening 41 of the cylinder 4, the plug 5 can be inserted from the rear end opening 42 of the cylinder 4. There is no need to insert the inside of the cylindrical body 4, and as a result, the inner diameter D of the regulating wall portion 44 can be set sufficiently small (that is, the protruding amount in the radial direction of the regulating wall portion 44 can be set sufficiently large). 5 A sufficient amount of contact between the rear surface and the regulating wall portion 44 can be obtained, and the plug body 5 can be reliably prevented from falling backward. The inner diameter C of the inner seal portion 43 refers to the minimum inner diameter of the inner seal portion 43. The inner diameter D of the restriction wall portion 44 is the minimum inner diameter of the restriction wall portion 44.

[3] In a third invention of the present application, in the first or second invention, the ink storage body 22 impregnated with ink is accommodated in the cylindrical body 4 in front of the plug body 5, and the ink storage body is stored. The pen tip 21 is connected to the front end of the ink cartridge 22, the rear end of the ink storage body 22 and the front surface of the plug body 5 are brought into contact with each other in the front-rear direction, and the plug body 5 is connected to the ink storage body 22 and the restriction wall portion 44. It is a requirement to hold in the front-rear direction. (Corresponding to FIGS. 1 to 7)

In the writing instrument 1 according to the third aspect of the present invention, the stopper 5 is sandwiched in the front-rear direction by the ink occlusion body 22 and the restriction wall portion 44 so that the ink occlusion body 22 moves the stopper 5 forward. While being blocked, the restriction wall 44 prevents the plug body 5 from moving backward. That is, the movement of the plug body 5 in the front-rear direction is reliably prevented, and the airtight fitting between the outer surface of the plug body 5 and the inner seal portion 43 of the inner surface of the cylinder body 4 is properly maintained for a long time.

[4] In a fourth invention of the present application, in the first, second, or third invention, the protruding member 6 is fitted on the inner surface of the rear end opening 42 of the cylindrical body 4, and the protruding member 6 A rear end portion is projected rearward from the rear end of the cylindrical body 4, an outward projection 61 is formed on the outer surface of the protruding member 6, and an inward projection 45 is formed on the inner surface of the cylindrical body 4 behind the regulating wall portion 44. Formed integrally, the outward projection 61 on the outer surface of the projecting member 6 and the inward projection 45 on the inner surface of the cylindrical body 4 are ridden in the front-rear direction, the outward projection 61 and the inward projection 45 are prevented from being detached, and It is a requirement that the inner diameter E of the inward projection 45 is smaller than the inner diameter D of the restriction wall portion 44. (Corresponding to FIGS. 1 to 5)

In the writing instrument 1 according to the fourth aspect of the present invention, the inward projection 45 formed integrally with the inner surface of the cylindrical body 4 is separated from the mold by forming the inner diameter E of the inward projection 45 smaller than the inner diameter D of the restriction wall portion 44. It is possible to avoid an undercut part at the time of molding. As a result, the amount of protrusion of the inward protrusion in the radially inward direction can be significantly larger than that of the inward protrusion formed of the conventional undercut portion, and the inward protrusion 45 and the outward protrusion 61 of the protrusion member 6 It is possible to firmly prevent the locking of the protruding member 6 and to prevent the protruding member 6 from falling off. The inner diameter E of the inward protrusion 45 is the minimum inner diameter of the inward protrusion 45.

[5] In the fifth invention of the present application, the writing instrument body 2 includes a pen tip 21 in which ink is accommodated and can eject ink at the front end, and the rear end portion of the writing instrument body 2 is formed by the cylinder 4. The cylindrical body 4 includes an inner hole penetrating in the front-rear direction, a front end opening 41 and a rear end opening 42 communicating with the inner hole, and the plug body 5 is press-fitted into the inner surface of the cylindrical body 4 A writing instrument that is fixed, blocks the ventilation inside the cylinder 4 between the front end opening 41 and the rear end opening 42 by the plug body 5, and contains ink in the cylinder 4 in front of the plug body 5. The plug body 5 is inserted into the cylinder body 4 from the front end opening of the cylinder body 4 so that the outer surface of the plug body 5 is airtightly fitted to the inner surface of the cylinder body 4, and at the same time, the plug body 5 It is required that the rear surface is brought into contact with the regulating wall portion 44 on the inner surface of the cylindrical body 4 in the front-rear direction.

According to the writing instrument manufacturing method of the fifth aspect of the present invention, it is not necessary to insert the plug 5 into the cylindrical body 4 from the rear end opening 42 of the cylindrical body 4, and as a result, the inner diameter D of the regulating wall 44 is reduced. It can be set sufficiently small (that is, the amount of protrusion of the regulating wall 44 inward in the radial direction can be set sufficiently large), and a sufficient amount of contact between the rear surface of the plug body 5 and the regulating wall 44 can be obtained. It is possible to reliably prevent the body 5 from falling backward, and as a result, the airtight fitting between the inner surface of the plug body 5 and the outer surface of the cylindrical body 4 can be maintained for a long time.

In the fifth aspect of the invention, the configuration in which the ink is accommodated in the cylinder 4 is, for example, a configuration in which the ink is directly accommodated in the cylinder 4 (so-called direct liquid type), or an ink occlusion impregnated with ink. The structure (what is called batting type) which accommodates a body in the cylinder 4 is mentioned.

[6] According to a sixth invention of the present application, in the method for manufacturing a writing instrument according to the fifth invention, the protruding member 6 is inserted into the rear end opening of the cylindrical body 4 from the rear to the front, It is a requirement that it is inserted into the inner surface of the rear end opening of the cylindrical body 4 behind the regulating wall 44 in a state of protruding rearward from the rear end of the cylindrical body 4.

According to the writing instrument manufacturing method of the sixth aspect of the present invention, since the plug body 5 and the protruding member 6 are inserted into the cylindrical body 4 from different directions, the plug body 5 and the protruding member 6 can easily interfere with each other. Therefore, the plug body 5 and the protruding member 6 can be properly attached.

In the present invention, the inner seal portion 43 includes, for example, an annular protrusion or an annular smooth surface. In the present invention, on the outer surface of the plug body 5, an annular seal portion (that is, the outer seal portion 51) formed of an annular protrusion or an annular smooth surface that is airtightly fitted to the inner seal portion 43 of the inner surface of the cylindrical body 4 is formed. It is preferred that

In the present invention, the restriction wall portion 44 includes, for example, an annular small inner diameter portion or a plurality of ribs extending in the axial direction. The inner diameter D of the restriction wall portion 44 refers to the diameter of an inscribed circle that is in contact with the radial top portions of the plurality of ribs in the cross section when the restriction wall portion 44 is a plurality of ribs extending in the axial direction.

In the present invention, the cylindrical body 4 only needs to constitute at least the rear end portion of the writing instrument main body 2, and the cylindrical body 4 may constitute substantially the entire writing instrument main body 2, or the cylindrical body 4. May constitute only the rear end of the writing instrument body. In the present invention, the configuration in which the cylinder 4 is fixed to the pen tip 21 is, for example, a configuration in which the pen tip 21 is directly fixed to the cylinder 4 or another member such as the pen tip holding cylinder 3 is attached to the cylinder 4. The structure which fixes the pen point 21 via is mentioned.

In the present invention, the protruding member 6 is, for example, a frictional discoloration member made of an elastic material that rubs thermochromic handwriting and thermally discolors the handwriting with frictional heat at that time, a pen tip 21 in front of the plug 5 and Examples thereof include a writing unit having a pen tip and an ink container independent from the ink container (such as the ink occluding body 22 and an ink tank), or a tail cap colored in ink color for ink color display.

According to the writing instrument of the present invention, it is possible to reliably prevent the plug body from dropping off to the rear of the shaft tube, and as a result, the hermetic fitting between the inner surface of the plug body and the outer surface of the cylinder body can be maintained for a long time.

According to the writing instrument manufacturing method of the present invention, it is possible to reliably prevent the plug body from falling off the rear side of the shaft cylinder, and as a result, the airtight fitting between the inner surface of the plug body and the outer surface of the cylinder body can be maintained for a long time.

It is a longitudinal cross-sectional view which shows the 1st Embodiment of this invention. It is a principal part expanded longitudinal cross-sectional view of FIG. It is the sectional view on the AA line of FIG. FIG. 3 is a sectional view taken along line BB in FIG. 2. It is a longitudinal cross-sectional view of the cylinder which fixed the stopper and the protrusion member in FIG. It is a longitudinal cross-sectional view which shows the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the cylinder which fixed the stopper in FIG.

<First Embodiment>
1 to 5 show a first embodiment of the present invention.
The writing instrument 1 of the present embodiment includes a pen tip 21, a pen tip holding cylinder 3 to which the pen tip 21 is fixed, a cylinder 4 connected to the rear end of the pen tip holding cylinder 3, and the cylinder. 4, the protruding member 6 fixed to the rear end opening 42, the plug 5 fixed to the inner surface of the cylinder 4 in front of the protruding member 6, the inside of the cylinder 4 in front of the plug 5, and the pen tip holding The writing instrument main body 2 is provided with an ink occlusion body 22 housed inside the cylinder 3.

Pen nib The pen nib 21 is made of a fiber resin processed body. In addition to this, the pen tip 21 may be, for example, a ballpoint pen tip, a heat-bonded processed body of fiber bundles, a felt processed body, a pipe-shaped pen body, a fountain pen type plate-shaped pen body having a slit at the tip, a brush pen body, Examples thereof include a porous foam of a synthetic resin and an extruded product of a synthetic resin having an axial ink guide path.

Ink occlusion body The ink occlusion body 22 only needs to be made of a member having continuous pores that can be impregnated with ink (that is, a porous material). Examples include a processed body, a felt resin processed body, a felt needle punch processed body, and an open-cell body of a synthetic resin. Further, the ink occluding body 22 may be provided with an outer skin made of a synthetic resin film or the like on its outer peripheral surface. The rear end portion of the pen tip 21 is pierced and connected to the front surface of the ink storage body 22.

Pen nib holding cylinder The pen nib holding cylinder 3 is obtained by injection molding of synthetic resin. In the pen tip holding cylinder 3, the pen tip 21 is press-fitted and fixed to the tapered front end portion, and the front end of the pen tip 21 projects forward from the tapered front end portion. A front portion of the ink storage body 22 is accommodated in the pen tip holding cylinder 3, and a rear end of the pen tip 21 is pierced and connected to the front end of the ink storage body 22. The rear end opening of the pen tip holding cylinder 3 is connected to the front end opening 41 of the cylinder 4 by airtight fitting. An air passage (not shown) is formed between the outer surface of the pen tip 21 and the inner surface of the pen tip holding cylinder 3 to allow communication between the inside of the pen tip holding cylinder 3 and the outside air.

-Cylindrical body The said cylindrical body 4 consists of a cylindrical body obtained by the injection molding of a synthetic resin. The cylindrical body 4 has an inner hole penetrating in the axial direction, and the inner hole communicates with the outside through the front end opening 41 and the rear end opening 42. The inner surface of the front end opening 41 of the cylinder 4 is connected to the outer surface of the rear end opening 42 of the pen tip holding cylinder 3 by airtight fitting.

An annular inner seal portion 43 is formed on the inner surface of the intermediate portion or the rear portion of the inner seal portion cylinder 4. The inner seal portion 43 is formed of an annular smooth surface or an annular protrusion. The inner diameter of the inner surface of the cylindrical body 4 from the front end opening 41 of the cylindrical body 4 to the inner seal portion 43 is formed so that the inner diameter C of the inner seal portion 43 is the smallest.

Restriction wall portion A restriction wall portion 44 is formed integrally on the inner surface of the cylindrical body 4 behind the inner seal portion 43. The restriction wall portion 44 includes a plurality of (here, four) ribs extending in the axial direction, but may be an annular small inner diameter portion. An inner diameter D (that is, a diameter of an inscribed circle in contact with the radial top of the rib) of the restriction wall portion 44 is formed smaller than an inner diameter C of the inner seal portion 43. The front end surface of the restriction wall portion 44 is formed perpendicular to the axis. still. The inner diameter D of the restriction wall 44 is the inner diameter of the front end of the restriction wall 44 in the present embodiment.

Inward protrusion An inward protrusion 45 is integrally formed on the inner surface of the cylinder 4 behind the regulating wall 44 (that is, the inner surface of the rear end opening 42 of the cylinder 4). The inward protrusion 45 includes an annular protrusion or a plurality of dispersed protrusions. An inner diameter (minimum inner diameter) E of the inward projection 45 is formed smaller than an inner diameter D of the restriction wall portion 44. The corner of the front end of the inward projection 45 is formed at an acute angle or a right angle. The rear surface of the inward projection 45 has an inclined surface that gradually increases in inner diameter toward the rear.

-Plug body The said plug body 5 is a bottomed cylindrical body obtained by the injection molding of a synthetic resin with the front end opened and the rear end closed. The plug body 5 is obtained by injection molding of a synthetic resin. The outer surface of the plug body 5 includes a small outer diameter portion at the front portion and a large outer diameter portion at the rear portion.

On the front end surface of the plug body 5 (the front end surface of the small outer diameter portion), a notch 52 that opens forward and penetrates in the radial direction is formed. The rear end surface of the ink occluding body 22 is brought into contact with the front end surface of the plug body 5. The notch 52 allows the rear end surface of the ink storage body 22 and the outside air to be vented.

An annular outer seal portion 51 is integrally formed on the outer surface of the plug body 5 (the outer surface of the large outer diameter portion of the plug body 5). The outer seal portion 51 is composed of an annular protrusion or an annular smooth surface. The outer seal portion 51 has an outer diameter slightly larger than the inner diameter C of the inner seal portion 43. Thereby, reliable airtight fitting between the outer seal portion 51 and the inner seal portion 43 is obtained.

The rear end surface of the plug body 5 (the bottom surface of the plug body 5) is a plane perpendicular to the axis. The rear end of the plug body 5 has an outer diameter larger than the inner diameter D of the restriction wall portion 44. The rear end of the plug body 5 abuts on the restriction wall portion 44, is disposed in front of the restriction wall portion 44, and does not protrude rearward from the rear end of the cylinder body 4. Thereby, a space in which the protruding member 6 can be sufficiently inserted into the rear end opening 42 of the cylinder 4 can be secured, and the protruding member 6 can be easily inserted into the inner surface of the rear end opening 42 of the cylinder 4. it can.

Further, the rear end of the plug 5 and the front end of the protruding member 6 are arranged in a non-contact state. Thereby, mutual interference between the plug body 5 and the protruding member 6 can be prevented, proper airtight fitting between the outer seal portion 51 of the plug body 5 and the inner seal portion 43 of the cylindrical body 4, and outward projection of the protruding member 6 Appropriate retaining locking between 61 and the inward projection 45 of the cylinder 4 is obtained.

Projecting member The projecting member 6 includes a large-diameter portion and a small-diameter portion integrally provided in front of the large-diameter portion, and is integrally formed of an elastic material. The protruding member 6 is made of an elastic material such as synthetic rubber or elastomer. In the present embodiment, the protruding member 6 employs a frictional discoloration member that rubs the surface of the thermochromic handwriting to thermally discolor the handwriting. In addition to this, the protruding member 6 made of the elastic material includes an eraser or an input member of an input pen used for a portable information terminal. The protruding member 6 is inserted into the rear end opening of the cylinder 4 from the rear to the front.

The rear surface of the large diameter portion has a convex curved surface shape. At the front end of the large-diameter portion, a shoulder is formed that can contact the opening end of the rear end opening 42 of the cylinder 4 (specifically, the rear end of the cylinder 4). The maximum outer diameter of the large diameter portion is set larger than the inner diameter of the rear end opening 42 of the cylinder 4 and smaller than the outer diameter of the rear end of the cylinder 4.

An annular outward projection 61 is integrally formed on the outer peripheral surface of the front end portion of the small diameter portion. The front surface of the outward projection 61 has an inclined surface (that is, a conical surface) whose outer diameter gradually increases toward the rear. The rear end of the outward projection 61 has a right or acute corner.

An outer diameter (maximum outer diameter) of the outward projection 61 is formed larger than an inner diameter E (minimum inner diameter) of the inward projection 45, and the outward projection 61 and the inward projection 45 can be securely locked. The outer diameter (maximum outer diameter) of the outward projection 61 is formed smaller than the inner diameter of the rear end opening 42 of the cylindrical body 4 behind the inward projection 45, and thereby the cylindrical body behind the outward projection 61 and the inward projection 45. 4 is maintained in a non-fitted state with the rear end opening inner surface, and the protruding member 6 can be smoothly inserted until just before the outward projection 61 gets over the inward projection 45. In a state where the insertion of the protruding member 6 into the rear end opening 42 of the cylindrical body 4 has been completed (override fitting is completed), the outer surface of the protruding member 6 behind the outward projection 61 and the inward projection 45 are fitted. To do.

In a state where the insertion of the protruding member 6 into the rear end opening 42 of the cylindrical body 4 is completed (a state where the overpass fitting is completed), the rear end (that is, the maximum outer diameter portion) of the outward projection 61 is the inward projection 45. An axial gap is formed between the front end of the inward projection 45 and the rear end of the outward projection 61, which is located in front of the front end (that is, the minimum inner diameter portion). Thereby, when the outward projection 61 rides over the inward projection 45 from the rear to the front, the outward projection 61 can surely get over the inward projection 45 even if the outward projection 61 and the inward projection 45 slip poorly.

Further, in a state where the insertion of the protruding member 6 into the rear end opening 42 of the cylindrical body 4 is completed (a state where the overpass fitting is completed), the outer surface of the outward projection 61 and the inner surface of the cylindrical body 4 (that is, the restriction wall). A gap in the radial direction is formed between the inner surface of the portion 44 and the inner surface of the portion 44. Thereby, when the outward projection 61 rides over the inward projection 45 from the rear to the front, the outward projection 61 can surely get over the inward projection 45 even if the outward projection 61 and the inward projection 45 slip poorly.

<Second Embodiment>
6 and 7 show a second embodiment of the present invention. The second embodiment is a form in which the protruding member 6 of the first embodiment is not provided, and other configurations are the same as those of the first embodiment.

The writing instrument 1 of the present embodiment includes a pen tip 21, a pen tip holding cylinder 3 to which the pen tip 21 is fixed, a cylinder 4 connected to the rear end of the pen tip holding cylinder 3, and a cylinder 4. From the writing instrument main body 2 provided with the stopper 5 fixed to the inner surface of the rear end opening 42 of the rear end, and the ink occlusion body 22 accommodated in the cylinder 4 in front of the stopper 5 and the nib holding cylinder 3. Become.

Pen nib The pen nib 21 is made of a fiber resin processed body. In addition to this, the pen tip 21 may be, for example, a ballpoint pen tip, a heat-bonded processed body of fiber bundles, a felt processed body, a pipe-shaped pen body, a fountain pen type plate-shaped pen body having a slit at the tip, a brush pen body, Examples thereof include a porous foam of a synthetic resin and an extruded product of a synthetic resin having an axial ink guide path.

Ink occlusion body The ink occlusion body 22 only needs to be made of a member having continuous pores that can be impregnated with ink (that is, a porous material). Examples include a processed body, a felt resin processed body, a felt needle punch processed body, and an open-cell body of a synthetic resin. Further, the ink occluding body 22 may be provided with an outer skin made of a synthetic resin film or the like on its outer peripheral surface. The rear end portion of the pen tip 21 is pierced and connected to the front surface of the ink storage body 22.

Pen nib holding cylinder The pen nib holding cylinder 3 is obtained by injection molding of synthetic resin. In the pen tip holding cylinder 3, the pen tip 21 is press-fitted and fixed to the tapered front end portion, and the front end of the pen tip 21 projects forward from the tapered front end portion. A front portion of the ink storage body 22 is accommodated in the pen tip holding cylinder 3, and a rear end of the pen tip 21 is pierced and connected to the ink storage body 2. The rear end opening of the pen tip holding cylinder 3 is connected to the front end opening 41 of the cylinder 4 by airtight fitting. An air passage (not shown) is formed between the outer surface of the pen tip 21 and the inner surface of the pen tip holding cylinder 3 to allow communication between the inside of the pen tip holding cylinder 3 and the outside air.

-Cylindrical body The said cylindrical body 4 consists of a cylindrical body obtained by the injection molding of a synthetic resin. The cylindrical body 4 has an inner hole penetrating in the axial direction, and the inner hole communicates with the outside through the front end opening 41 and the rear end opening 42. The inner surface of the front end opening 41 of the cylinder 4 is connected to the outer surface of the rear end opening 42 of the pen tip holding cylinder 3 by airtight fitting.

An annular inner seal portion 43 is formed on the inner surface of the intermediate portion or the rear portion of the inner seal portion cylinder 4. The inner seal portion 43 is formed of an annular smooth surface or an annular protrusion. The inner diameter of the inner surface of the cylindrical body 4 from the front end opening 41 of the cylindrical body 4 to the inner seal portion 43 is formed so that the inner diameter C of the inner seal portion 43 is the smallest.

Restriction wall portion A restriction wall portion 44 is formed integrally on the inner surface of the cylindrical body 4 behind the inner seal portion 43. The restriction wall portion 44 includes a plurality of (here, four) ribs extending in the axial direction, but may be an annular small inner diameter portion. An inner diameter D (that is, a diameter of an inscribed circle in contact with the radial top of the rib) of the restriction wall portion 44 is formed smaller than an inner diameter C of the inner seal portion 43. The front end surface of the restriction wall portion 44 is formed perpendicular to the axis. still. The inner diameter D of the restriction wall 44 is the inner diameter of the front end of the restriction wall 44 in the present embodiment.

-Plug body The said plug body 5 is a bottomed cylindrical body obtained by the injection molding of a synthetic resin with the front end opened and the rear end closed. The plug body 5 is obtained by injection molding of a synthetic resin. The outer surface of the plug body 5 includes a small outer diameter portion at the front portion and a large outer diameter portion at the rear portion.

On the front end surface of the plug body 5 (the front end surface of the small outer diameter portion), a notch 52 that opens forward and penetrates in the radial direction is formed. The rear end surface of the ink occluding body 22 is brought into contact with the front end surface of the plug body 5. The notch 52 allows the rear end surface of the ink storage body 22 and the outside air to be vented.

An annular outer seal portion 51 is integrally formed on the outer surface of the plug body 5 (the outer surface of the large outer diameter portion of the plug body 5). The outer seal portion 51 is composed of an annular protrusion or an annular smooth surface. The outer seal portion 51 has an outer diameter slightly larger than the inner diameter C of the inner seal portion 43. Thereby, reliable airtight fitting between the outer seal portion 51 and the inner seal portion 43 is obtained.

The rear end surface of the plug body 5 (the bottom surface of the plug body 5) is a plane perpendicular to the axis. The rear end of the plug body 5 has an outer diameter larger than the inner diameter D of the restriction wall portion 44. The rear end of the plug body 5 abuts on the restriction wall portion 44, is disposed in front of the restriction wall portion 44, and does not protrude rearward from the rear end of the cylinder body 4. As a result, it is possible to avoid inadvertently pressing the rear end of the plug body 5 forward, and as a result, the airtight fitting state between the outer seal portion 51 of the plug body 5 and the inner seal portion 43 of the cylinder body 4 is erroneously released. Can be prevented.

DESCRIPTION OF SYMBOLS 1 Writing instrument 2 Writing instrument main body 21 Pen tip 22 Ink occlusion body 3 Pen tip holding cylinder 4 Tube body 41 Front end opening part 42 Rear end opening part 43 Inner seal part 44 Restriction wall part 45 Inward protrusion 5 Plug body 51 Outer seal part 52 Notch 6 Protruding member 61 Outward projection C Inner seal inner diameter D Inner diameter E of regulating wall E Inward projection inner diameter

Claims (6)

It consists of a writing instrument body with a pen tip at the front end that contains ink inside and can eject the ink,
The rear end portion of the writing instrument body is constituted by a cylinder, and the cylinder includes an inner hole penetrating in the front-rear direction, and a front end opening and a rear end opening communicating with the inner hole.
A stopper is press-fitted and fixed to the inner surface of the cylindrical body, the ventilation inside the cylindrical body between the front end opening and the rear end opening is blocked by the plug, and ink is accommodated inside the cylindrical body in front of the plug. A writing instrument,
An inner seal portion is formed on the inner surface of the cylindrical body to be airtightly fitted to the outer surface of the plug body. The inner surface of the cylindrical body behind the inner seal portion is in contact with the rear surface of the plug body in the front-rear direction and to the rear of the plug body. A writing instrument characterized in that a regulating wall portion for preventing movement is integrally formed. 2. The writing instrument according to claim 1, wherein an inner diameter of the inner surface of the cylindrical body in front of the inner seal portion is formed larger than an inner diameter of the inner seal portion, and an inner diameter of the regulation wall portion is smaller than an inner diameter of the inner seal portion. . An ink storage body impregnated with ink is accommodated in the inside of the cylindrical body in front of the plug body, a pen tip is connected to the front end of the ink storage body, and the rear end of the ink storage body and the front surface of the plug body are connected. The writing instrument according to claim 1, wherein the writing instrument is abutted in the front-rear direction, and the stopper is sandwiched in the front-rear direction by the ink occlusion body and the restriction wall portion. A projecting member is fitted to the inner surface of the rear end opening of the cylindrical body, the rear end portion of the projecting member is projected rearward from the rear end of the cylindrical body, and outward projections are formed on the outer surface of the projecting member, An inward projection is integrally formed on the inner surface of the cylindrical body behind the regulating wall, and the outward projection on the outer surface of the protruding member and the inward projection on the inner surface of the cylindrical body are moved over in the front-rear direction, and the outward projection and the inward The writing instrument according to any one of claims 1 to 3, wherein a projection is prevented from coming off and an inner diameter of the inward projection is smaller than an inner diameter of the restriction wall portion.
The writing instrument main body is provided with a pen nib in which ink is accommodated and the ink can be discharged at the front end, the rear end portion of the writing instrument main body is formed of a cylindrical body, and the cylindrical body penetrates in the front-rear direction. And a front end opening and a rear end opening communicating with the inner hole, and a stopper is press-fitted and fixed to the inner surface of the cylinder, and the cylinder between the front end opening and the rear end opening by the stopper A method of manufacturing a writing instrument that blocks ventilation inside the body and contains ink inside the cylindrical body in front of the plug body, the plug body is inserted into the cylindrical body from the front end opening of the cylindrical body, A method of manufacturing a writing instrument, wherein the outer surface of the plug body is airtightly fitted to the inner surface of the cylindrical body, and the rear surface of the plug body is brought into contact with the regulating wall portion of the inner surface of the cylindrical body in the front-rear direction. A projecting member is inserted into the rear end opening of the cylindrical body from the rear and the rear end opening of the cylindrical body behind the regulating wall in a state where the projecting member projects rearward from the rear end of the cylindrical body. The manufacturing method of the writing instrument of Claim 5 inserted in an inner surface.

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