JPH08207486A - Ball-point pen - Google Patents

Abstract

PURPOSE: To obtain an adequate ink-backflow preventive function and to facilitate assembly by installing a valve cylinder body equipped with a regulation part which contacts a valve body when the valve body is moved forward and a valve seat which prevents ink from flowing by the contact with the valve body when the valve body is moved backward separately from an ink receiving tube. CONSTITUTION: The small-diameter part 71, middle-diameter part 72, and large-diameter part of an ink receiving tube 7, which are arranged in sequence from the front end to the rear part of the tube 7, are formed integrally, and a valve unit 4 and a pen point 3 are pushed into the inner wall of the small diameter part to be fixed. The valve unit 4 is composed of a valve cylinder body 5 made of an elastic material and a valve body made of a metal ball, and in the cylindrical valve cylinder body 5, a regulation part 52 and a valve seat 51 are formed integrally in the front and rear parts of the inner wall. A valve chest 53 is formed between the valve seat 51 and the regulation part 52, a valve body 6 is placed freely movably in the valve chest 53, and the valve chest 53 is made to communicate with the outside from both ends of the valve cylinder body 5 through the valve hole 54 of the valve seat 51 and the ink passage hole 55 of the regulation part 52.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a ballpoint pen.
More specifically, the present invention relates to a ballpoint pen in which a valve chamber is provided on a front inner wall of an ink containing tube and a valve element for preventing backflow is housed in the valve chamber in a freely movable manner.

[0002]

2. Description of the Related Art Conventionally, many ballpoint pens of this type are provided with a backflow prevention valve mechanism for the purpose of preventing the ink from flowing backward to the rear (tail end side) of the main body due to gravity when the pen tip is in the upward state. It is disclosed (for example, Japanese Utility Model Publication No. 6-74378).

[0003] In the above-mentioned specification No. 6-74378,
A valve seat is provided on the inner peripheral surface of the front end side where the tip of the ink containing tube is mounted, and a regulating portion for restricting the amount of sway of the ball valve is further provided on the inner peripheral surface of the front end side with a proper distance from the valve seat. Is provided to form a valve chamber between the restricting portion and the valve seat, and a ball valve is inserted in the valve chamber so that the ball valve is freely movable therein. Disclosed, specifically, a structure in which the valve seat and the restriction portion are integrally molded and provided by injection molding of a hard synthetic resin such as vinyl chloride is disclosed, which makes it possible to easily and inexpensively manufacture a backflow prevention. It is described that a ballpoint pen having a mechanism can be provided at low cost.

However, a hard material (hard synthetic resin or metal) is generally used for the ink containing tube in order to securely hold the pen tip without wobbling. Therefore, when the ink containing pipe and the valve chamber (that is, the valve seat and the restricting portion) are integrally formed as in the conventional configuration, the valve seat and the restricting portion are naturally formed of a hard material.

When the valve seat is made of a hard material, if the shape of the valve seat varies greatly, the close contact (sealing property) with the valve body may become insufficient. Further, when the valve body is structured to be pushed into the valve chamber by expanding the valve seat or the restricting portion by utilizing the elastic deformation of the valve chamber wall, the valve seat or the restricting portion on the side where the valve body is press-fitted is If it is made of a hard material, the valve seat or the restriction portion may be plastically deformed by the valve body at the time of press fitting, and the sealing function of the valve seat or the stopper function of the restriction portion may be lost.

Further, in the case of the above-mentioned construction in which the valve body is press-fitted into the valve chamber from the valve seat side or the regulating portion side to be assembled, the valve seat or the regulating portion on the side where the valve body is press-fitted due to the risk of plastic deformation. It is not possible to make the amount of inward projection of the extremely large. That is, normally, the difference between the maximum outer diameter of the valve body and the minimum inner diameter of the valve seat (valve hole) or the restriction portion (ink passage hole) cannot be set to a large value, and the valve seat or the restriction portion from the valve chamber inner wall cannot be set. The amount of protrusion is small. In addition, when the inner wall of the valve chamber and the valve seat or restriction part are made of synthetic resin by injection molding, the valve seat or restriction part is an undercut part, so there is a limit to its size and it is set too large. Can not.

If the amount of protrusion of the restriction portion is small, the reliable contact between the valve element and the restriction portion, that is, the function of preventing the valve ball from falling out is insufficient depending on the dimensional variation of the valve element and the restriction portion. . Furthermore, when the manufacturing process has a step of pushing out the ink to the pen tip by a centrifuge, the valve element bites into the restriction portion and the valve element smoothly moves back and forth because the protruding amount of the restriction portion is small. There is also a risk of inhibiting.

Further, since the amount of protrusion of the valve seat is small, a rearward impact (for example, an impact between the tail end side and the floor due to a drop, or a ballpoint pen refill of a knock-type writing instrument, the refill is There is a risk that the valve element may drop behind the valve seat or bite into the valve seat due to the impact of the spring when stored in the writing instrument body.

Further, in the above-mentioned Japanese Utility Model Laid-Open No. 6-74378, an ink backflow prevention mechanism is built in a tail plug having an outside air intake hole which is fitted and mounted in a rear end opening of an ink containing tube. Even if a low-viscosity ink is used as the ink to be filled in the ink containing tube, or if the ball-point pen is dropped and a fairly large impact is applied, it is possible to achieve a synergistic effect with the built-in ink backflow prevention mechanism on the front end side. It is stated that the backflow of ink can be prevented more completely.
However, when a plurality of valve chambers are provided as described above, the valve chambers and the valve body components must be manufactured and controlled, which is not efficient.

Further, the specification of Japanese Utility Model Laid-Open Publication No. 6-74378 describes a structure in which the tip is directly attached to the tip opening of the ink containing tube. In this case,
It is difficult to fix a ballpoint pen tip having an outside diameter that is too small, and generally, a cutting type ballpoint pen tip (i.e., a ball holding portion with a ball receiving seat and a tapered taper portion is cut at the tip of a metal material). Molded type)
Is adopted, and the outer diameter of the rear part of the ballpoint pen tip is 2.3 mm
It has a relatively large diameter in the front and back. That is, the conventional configuration is
It is not suitable for a pipe type ball-point pen tip having an outer diameter as small as 2 mm or less (a type in which a ball receiving seat is obtained by an inward protruding portion formed by pressing and deforming the vicinity of the tip of a metal pipe inwardly).

[0011]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems of the prior art, in which the material and shape of the valve chamber are
It can be set independently from the ink storage tube,
An object of the present invention is to provide a ball-point pen which has a sufficient backflow prevention function, is easy to manufacture, and has a simple structure. Another object of the present invention is to provide a ballpoint pen having a backflow prevention function with an optimal structure for a pipe type ballpoint pen tip.

[0012]

According to the present invention, a fixing portion 74 to which the pen tip 3 is fixed is provided on the inner wall of the front portion of the ink containing tube 7, and a valve is provided inside the ink containing tube 7 behind the fixing portion 74. A ball-point pen having a chamber 53 in which the valve body 6 for backflow prevention is movably accommodated in the valve chamber 53. The ball-point pen has a restricting portion 52 with which the valve body 6 comes into contact when moved forward and a rearward movement. The valve seat 5 that prevents the ink flow by the contact of the valve body 6 when
1 is provided in the front and rear positions of the inner wall of the valve chamber 53 separately from the ink containing tube 7, and the valve chamber 53 of the valve cylinder 5 is provided.
It is required that the valve unit 6 be accommodated in the inside of the valve unit 4 and that the valve unit 4 be disposed on the inner wall of the front portion of the ink containing pipe 7.

In the ballpoint pen, the valve cylinder 5
However, it is preferable that the restricting portion 52 and the valve seat 51 are integrally formed with the inner wall of the valve chamber 53 by a synthetic resin.

Further, in the above ballpoint pen, the pen tip 3 is made of a metal cylindrical ballpoint pen tip 1 which rotatably holds the ball 14 at its tip, and a synthetic resin which holds the ballpoint pen tip 1 in the front part. It is preferable that the structure is composed of the cylindrical holder 2. More specifically, the ball-point pen tip 1 includes a tip edge portion 12 formed by pressing and deforming the tip of a metal pipe 11 having a substantially uniform thickness from the outside to the inside in the radial direction, and the pipe 11. A pipe type having a configuration in which the ball 14 is rotatably held at the tip by the ball receiving seat 13 formed by pressing and deforming the vicinity of the tip inward is effective.

In the ballpoint pen, the valve unit 4
However, it is preferable that the pen tip 3 is brought into contact with the rear end of the pen tip 3 (specifically, the rear end of the holder 2 or the rear end of the ballpoint pen tip 1).

Further, in the ball-point pen of the present invention, the valve unit 4 is arranged on the inner wall of the front portion of the ink containing tube 7, and the valve unit 4 is provided on the inner wall of the rear end of the ink containing tube 7.
Can also be provided. At this time, the ink containing tube 7
The valve unit 4 arranged on the inner wall of the front part of the
It is preferable that the valve unit 4 disposed on the inner wall of the rear end has the same size and the same configuration.

[0017]

With the structure of claim 1, the material and shape of the valve chamber 53 can be formed independently of the ink containing tube 7. Thereby, the desired material and shape of the valve chamber 53 can be freely set so as to have a sufficient backflow prevention function.

According to the structure of claim 2, the ink containing tube 7
Independently of the above, it is possible to select a relatively soft material as the material of the valve chamber 53, and as a result, it is possible to set the soft valve seat 51 and the soft restricting portion 52 with a large protruding amount. The soft valve seat 51 can absorb variations in the shape of the valve seat 51, and a reliable sealing property with the valve body 6 can be obtained. Further, the soft restriction portion 52 allows the valve element 6 to be smoothly inserted into the valve chamber 53 without damaging the restriction portion 52 when the valve element 6 is press-fitted. The large protrusion amount of the restricting portion 52 ensures reliable contact with the valve body 6, and the valve body 6 during the ink discharging process by the centrifuge.
Is prevented from biting.

According to the structure of claim 3, the ink containing tube 7
By interposing the holder 2 between the ball-point pen tip 1 and the ball-point pen tip 1, it becomes possible to attach the ball-point pen tip 1 having a relatively small diameter (for example, a pipe-type ball-point pen tip).

According to the structure of claim 4, since the rear end of the pen tip 3 has a function of positioning and abutting the valve unit 4, it is not necessary to provide a protrusion or a step for abutting on the inner wall of the ink containing tube 7, which is simple. It becomes a structure. Further, when the holder 2 is attached to the ink containing tube 7, the rear end of the holder 2 and the valve unit 4 are
The valve unit 4 can be mounted at the same time with the tip end abutted, and the assembly process can be simplified.

According to the fifth aspect of the present invention, in addition to the prevention of ink backflow that occurs when the pen tip 3 is stored in the upward direction, the ink backflow that occurs due to a momentary large rearward impact can be prevented more reliably. . Further, since the valve unit 4 is unitized, even if the number of parts is increased, the parts can be shared and the quality control is sufficiently performed, which is advantageous in manufacturing.

[0022]

Embodiments of the present invention will be described with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. In this embodiment, a refill having a structure in which an ink containing tube 7 and a ball-point pen tip 1 made of metal are connected via a holder 2 made of synthetic resin which is a cylindrical connecting member (that is, a main body having a grip portion (not shown)). It is a replaceable ballpoint pen refill that is housed inside). The refill has a ball-point pen tip 1 and a support tube 8 at the tip of the holder 2.
And the holder 2 (pen tip 3) to which the ball-point pen tip 1 and the support cylinder 8 are fixed is press-fitted and fixed to the tip opening (fixing portion 74) of the ink containing tube 7.

The ink containing tube 7 is made of a relatively hard material, that is, synthetic resin (for example, polyacetal, polypropylene, polyethylene, ABS resin, PET resin, etc.).
Or metal (for example, copper alloy such as brass or stainless steel). This securely holds the pen tip 3 without wobbling. The ink containing tube 7 of the present embodiment is a cylindrical injection molded body made of a transparent or translucent synthetic resin (for example, polypropylene, polyretien) resin, and has a small diameter portion 71 and a medium diameter portion 72 in order from the tip to the rear. , And the large-diameter portion 73 are integrally connected.

Further, inside the ink containing tube 7 (mainly in the large diameter portion 73), a low-viscosity ink, a low-viscosity to medium-viscosity oil-based ink, or an ink 76 having a shear thinning property (for example, a shear rate of 384 s) is used. Ink having a viscosity at ^-1 of 10 to 150 mPa · s at a temperature of 20 ° C) is stored. At the rear end of the ink 76, a backflow preventing agent 77 (for example, a grease-like material) that moves forward as the ink 76 is consumed is stored.

Further, at the rear end opening of the ink containing tube 7,
A tail plug 9 made of a synthetic resin (for example, polypropylene, polyethylene, etc.) injection molded body is fitted. The tail plug 9
Has an air passage hole 91 penetrating the shaft center thereof, and a flange portion 92 that abuts the rear end edge portion of the ink containing tube 7 is formed at the rear end, and the inner wall of the ink containing tube 7 is in front of the flange portion 92. And a mounting tube portion 93 that is fitted in the concave and convex portions are integrally provided. In addition, at the tip of the tail plug 9 in front of the mounting cylinder portion 93, the small diameter cylinder portion 9
4 are formed integrally with each other, whereby an annular space 95 is formed between the outer peripheral surface of the small diameter cylindrical portion 94 and the inner peripheral surface of the ink containing tube 7.
Is formed. The space portion 95 serves as a storage space for the backflow preventing agent 77 when it moves rearward, and prevents the backflow preventing agent 77 and the ink 76 from leaking from the rear end of the ink containing tube 7. Further, the tail plug 9 is colored in substantially the same color as the ink 76, and the ink color is displayed by the colored collar portion 92 exposed from the rear end of the ink containing tube 7.

The valve unit 4 and the pen tip 3 (specifically, the ball-point pen tip 1 and the support) are attached to the inner wall of the small diameter portion 71 of the ink containing tube 7 (the valve unit fixing portion 75 and the pen tip fixing portion 74). A holder 2) having a tube 8 is press-fitted and fixed. Due to the press-fitting and fixing, the inner diameter of the inner wall of the small diameter portion 71 is set to be slightly smaller than the outer diameter of the valve unit 4 (valve tubular body 5) and the outer diameter of the mounting tubular portion 24 of the holder 2.

The holder 2 is, like the ink containing tube 7, a relatively hard material, that is, a synthetic resin (for example, polyacetal, polypropylene, polyethylene, ABS).
It is formed of a resin or the like) or a metal (for example, a copper alloy such as brass or stainless steel). Thereby, the ball-point pen tip 1 is securely held without wobbling. In this embodiment, a polypropylene resin injection molded body is used.

The holder 2 has a chip mounting hole 2 at the front.
1 and the locking wall portion 22 are provided, and the ballpoint pen tip 1
However, the rear end is brought into contact with the locking wall portion 22 and, at the same time, is press-fitted and fixed in the chip mounting hole 21. A communication hole 23 is provided in the locking wall portion 22 to connect the chip mounting hole 21 and the ink circulation hole 26 in the rear portion. A mounting cylinder portion 24 is provided so as to project from the rear portion of the holder 2, and the mounting cylinder portion 24 serves as a tip opening portion (small diameter portion 7) of the ink containing tube 7.
1 is press-fitted and fixed to the fixing portion 74) on the inner peripheral surface. A step 25 is formed at the base of the mounting tube 24, and the step 25
The leading edge of the small diameter portion 71 is in contact with.

The ballpoint pen tip 1 used in this embodiment is a so-called pipe type ballpoint pen,
It is composed of a cylindrical pipe 11 made of metal (for example, made of stainless steel) having a substantially uniform wall thickness. Then, in the vicinity of the tip of the pipe 11, a plurality of inner protrusions are formed on the outer peripheral surface at equal intervals at a plurality of locations (three or more locations) from the outside by being radially deformed (plastically deformed). Ball seat 1
3 is formed. An inwardly tapered tip edge portion 12 is formed at the tip of the pipe 11 by being pressed and deformed (plastically deformed) inward. A ball 14 made of cemented carbide is disposed between the front surface of the ball receiving seat 13 and the rear surface of the tip edge portion 12 and is rotatably held by the ball receiving seat 13 and the tip edge portion 12. It Here, the outer diameter of the pipe 11 is 1.1 mm or less, the wall thickness of the pipe 11 is 0.15 mm or less, and the outer diameter of the ball 14 is 0.7 mm.
It is effective to have a diameter of 5 mm or less, whereby the ballpoint pen tip 1 for fine characters having a narrow handwriting width can be applied. More preferably, it is effective that the outer diameter of the pipe 11 is 0.75 mm or less, the wall thickness of the pipe 11 is 0.15 mm or less, and the outer diameter of the ball 14 is 0.45 mm or less. An ultrafine ballpoint pen tip 1 having a narrower width can be applied. In this embodiment, the ball-point pen tip 1 is in the shape of a thin pipe, and the front portion of the holder 2 (the outer peripheral surface of the tip mounting hole 21) is made of metal for the purpose of preventing wobbling and bending during writing. Support tube 8
Is stuck. The support cylinder 8 has a small-diameter front part supporting the outer peripheral surface of the ball-point pen tip 1, and a large-diameter rear part attached to the front peripheral surface of the holder 2.

2 and 3 show the valve unit 4 of the first embodiment. The valve unit 4 is made of an elastically deformable material, that is, a soft synthetic resin (for example, polypropylene,
A valve cylinder 5 made of polyethylene, synthetic rubber, various elastomers, etc., and a metallic spherical valve body 6. In this embodiment, the valve tubular body 5 has a substantially cylindrical shape,
It is obtained by injection molding of soft polypropylene or polyethylene, and the restricting portion 52 and the valve seat 51 are integrally provided at the front and rear positions of the inner wall of the valve cylinder 5. Further, the valve seat 51
And the restriction portion 52, a valve chamber 53 having a space having an inner diameter larger than the outer diameter of the valve body 6 (a metallic spherical body) is formed, and the valve body 6 floats in the valve chamber 53. It can be accommodated. The valve chamber 53 communicates with both ends of the valve cylinder 5 to the outside through the valve hole 54 of the valve seat 51 and the ink passage hole 55 of the restriction portion 52. Further, it is effective that the valve body 6 has a specific gravity heavier than the specific gravity of the ink 76 so that the valve body 6 can quickly drop and move in the ink 76 due to gravity.
Here, a metal material is used. Further, tapered chamfers 56 are formed on the outer peripheral portions of both ends of the valve tubular body 5, and when the valve unit 4 is press-fitted into the inner wall (fixed portion 75) of the small diameter portion 71 of the ink containing tube 7, Allows smooth insertion without getting caught.

The restricting portion 52 is preferably a plurality of inward projecting portions, and here two projecting ridges provided at opposing positions are adopted. When the valve body 6 is in contact with the regulating portion 52,
The size and shape are set so that the valve body 6 can be prevented from falling off and ink can flow. That is, since the lateral cross-sectional shape of the ink passage hole 55 formed by the restriction portion 52 is a substantially quadrangular non-circular shape as shown in FIG. 3, even if the spherical valve body 6 contacts the restriction portion 52. , Ink can be distributed. In the valve unit 4 of the present embodiment, in the downward state of the pen tip 3 of the ballpoint pen, the valve body 6 moves downward due to gravity and is stopped by the regulating portion 52 to prevent the valve body 6 from coming off, and the ink It can be distributed and written.

On the other hand, the valve seat 51 is formed in the shape of a conical concave surface, and a valve hole 54 (having an inner diameter smaller than the outer diameter of the valve body 6) which communicates the valve chamber 53 with the outside is provided at the center thereof. Has been done. In the valve unit 4 of this embodiment, when the pen tip 3 of the ballpoint pen is in the upward state, the valve body 6 falls downward due to gravity and is brought into close contact with the valve seat 51, so that backflow of ink is prevented. Alternatively, when an impact is applied to the rear end of the ballpoint pen, the valve body 6 is momentarily brought into close contact with the valve seat 51 before the ink moves rearward, and the backflow of the ink is blocked.

FIG. 4 shows a method of assembling the valve unit 4 of FIG. 2, in which the valve body 6 is press-fitted into the valve chamber 53 of the valve cylinder 5 from the side of the restricting portion 52. At this time, the valve body 6 has the regulating portion 5
2 is momentarily pushed outward in the radial direction and elastically deformed. Then, the valve body 6 is movably accommodated in the valve chamber 53, and the valve unit 4 is completed. Here, the regulation unit 5
Since the front surface of 2 (projection) is a gentle slope,
It becomes possible to press-fit the valve body 6 more smoothly.

The valve unit 4 can be inserted from the front end opening portion of the ink containing tube 7 and press-fitted and fixed to the fixing portion 75 in the small diameter portion 71. Either method of press-fitting and fixing to the fixing portion 75 on the inner surface of the portion 71 may be used. In the present embodiment, the method of inserting from the tip opening of the ink containing tube 7 is adopted, and the holder 2
The rear end can press-fit the holder 2 at the same time when the holder 2 is press-fitted while pressing the end of the valve unit 4 on the side of the restricting portion 52 toward the rear side, which simplifies the assembling work. The valve unit 4 is tightly fitted to the fixing portion 75 on the inner circumference of the small diameter portion 71 of the ink containing tube 7, and the valve tube body 5 is attached to the rear end of the holder 2.
The tip (end on the side of the restricting portion 52) is stopped.

5 and 6 show another example of the valve unit 4 (first
-Valve unit applicable to the ballpoint pen of the fifth embodiment 4)
Indicates. As in FIGS. 2 and 3, the valve unit 4 includes a valve cylinder 5 made of a flexible material, that is, an elastically deformable soft synthetic resin (for example, polypropylene, polyethylene, synthetic rubber, various elastomers), and a metal. And a spherical valve body 6 made of steel. In this embodiment, the valve cylinder 5 has a substantially cylindrical shape and is obtained by injection molding of soft polypropylene or polyethylene, and the restricting portion 52 and the valve seat 51 are integrally formed at the front and rear positions of the inner wall of the valve cylinder 5. It is provided in. Further, between the valve seat 51 and the restriction portion 52, a valve chamber 5 having a space having an inner diameter larger than the outer diameter of the valve body 6 (a metallic spherical body).
3 is formed, and the valve body 6 is movably accommodated in the valve chamber 53. The valve chamber 53 has a valve hole 54 in the valve seat 51.
Through the ink passage hole 55 of the restriction portion 52, the both ends of the valve cylinder 5 communicate with the outside. Further, the valve body 6 is
It is effective to have a specific gravity heavier than that of the ink 76 so that the ink 76 can quickly drop and move in the ink 76. Here, a metal material is used. Also,
A tapered chamfer 56 is formed on the outer peripheral portion of both ends of the valve cylinder 5.
Is formed, which enables smooth insertion without catching when the valve unit 4 is press-fitted into the inner wall (fixed portion 75) of the small diameter portion 71 of the ink containing tube 7.

The restriction portion 52 is preferably a plurality of inward projections. Specifically, a plurality of projections (specifically three projections) provided on the inner wall of the valve cylinder 5 and having a gentle spherical surface are provided. Protrusion)
Has been adopted. The size and shape of the regulating portion 52 are set so as to regulate the drop-out of the valve body 6 and allow the ink to flow when the valve body 6 abuts. That is,
As shown in FIG. 6, the cross-sectional shape of the ink through hole 55 formed by the restriction portion 52 is a substantially triangular non-circular shape, so that even if the spherical valve body 6 abuts on the restriction portion 52,
Ink can be distributed. The valve unit 4 of this embodiment (see FIG.
6), in the downward state of the pen tip 3 of the ballpoint pen, the valve body 6 moves downward due to gravity, and
The valve body 6 is prevented from coming into contact with the valve body 6 and the valve body 6 is prevented from coming off, and ink circulation and writing are possible.

On the other hand, the valve seat 51 is formed in the shape of a conical concave surface, and a valve hole 54 (having an inner diameter smaller than the outer diameter of the valve body 6) which communicates the valve chamber 53 with the outside is provided at the center thereof. Has been done. The valve unit 4 (FIGS. 5 and 6) of this embodiment is
In the upward state of the pen tip 3 of the ballpoint pen, the valve body 6 falls downward due to gravity and is brought into close contact with the valve seat 51, preventing backflow of ink. Alternatively, when an impact is applied to the rear end of the ballpoint pen, the valve body 6 is momentarily brought into close contact with the valve seat 51 before the ink moves rearward, and the backflow of the ink is blocked.

7 and 8 show another example of the valve unit 4 (first
-Valve unit applicable to the ballpoint pen of the fifth embodiment 4)
Indicates. The valve unit 4 is made of a flexible material, that is,
Valve cylinder 5 made of soft synthetic resin (for example, polypropylene, polyethylene, synthetic rubber, various elastomers, etc.)
And a spherical valve body 6 made of metal. In this embodiment,
The valve cylinder 5 has a substantially cylindrical shape, is obtained by injection molding of soft polypropylene or polyethylene, and a valve seat 51 is integrally provided on the front portion of the inner wall of the valve cylinder 5. On the other hand, a regulating member (a member different from the valve tubular body 5) made of a plate made of metal or hard synthetic resin is press-fitted and fixed to the rear portion of the inner wall of the valve tubular body 5, whereby the regulating portion 52 is formed. are doing. Further, a space between the valve seat 51 and the restriction portion 52 is a valve chamber 53 having a space having an inner diameter larger than the outer diameter of the valve body 6.
Is formed, and the valve body 6 is accommodated in the valve chamber 53 in a freely movable manner. The valve chamber 53 includes a valve hole 54 of the valve seat 51,
Through the ink passage hole 55 of the restriction portion 52, the valve cylinder body 5 is opened to the outside from both ends. Further, it is effective that the valve body 6 has a specific gravity heavier than the specific gravity of the ink 76 so that the valve body 6 can quickly drop and move in the ink 76 due to gravity. Here, a metallic material is adopted. Further, the outer peripheral portions of both ends of the valve cylinder body 5 are provided with tapered chamfers 56, and are smooth without being caught when they are press-fitted into a fixing portion 75 provided on the inner wall of the small diameter portion 71 of the ink containing tube 7. Allows easy insertion.

The restricting portion 52 (restricting member) is dimensioned and shaped so as to restrict the drop-off of the valve body 6 and allow ink to flow when the valve body 6 is abutted. That is, the regulating member is provided so as to extend substantially in the center of the rear end opening of the valve cylinder 5. As shown in FIG. 8, the cross-sectional shape of the ink through hole 55 formed by the regulation member is a substantially semicircular non-circular shape which is divided into two by the regulation member and the inner wall of the valve cylinder body 5, so that the spherical valve is formed. Even if the body 6 contacts the regulation portion 52, the ink can flow. In the valve unit 4 (FIGS. 7 and 8) of the present embodiment, when the ballpoint pen is in the downward state of the pen tip 3, the valve body 6 moves downward due to gravity and abuts against the restricting portion 52, so that the valve body 6 comes off. In addition to being prevented, ink circulation and writing are possible.

On the other hand, the valve seat 51 is formed in the shape of a conical concave surface, and a valve hole 54 (having an inner diameter smaller than the outer diameter of the valve body 6) which communicates the valve chamber 53 with the outside is provided at the center thereof. Has been done. The valve unit 4 (FIGS. 7 and 8) of this embodiment is
When the ballpoint pen is in the upward state of the pen tip 3, the valve body 6 falls downward due to gravity and is brought into close contact with the valve seat 51, so that backflow of ink is blocked. Alternatively, when an impact is applied to the rear end of the ballpoint pen, the valve body 6 is momentarily brought into close contact with the valve seat 51 before the ink moves rearward, and the backflow of the ink is blocked.

Further, the valve unit 4 (FIGS. 2 and 3, 5, 5 and 6, 7 and 8) of the present invention includes the ink containing tube 7
The inner wall of the small diameter portion 71 (fixed portion 75) of the valve tubular body 5
It is preferable that the ink flow is prevented from flowing between the outer peripheral surface and the inner peripheral surface of the fixing portion 75. For that purpose, a structure in which the small diameter portion 71 having the same shape as the outer circumference of the valve cylinder 5 is press-fitted is simple and effective. However, in addition to this, the outer peripheral surface of the valve cylinder 5 and the small diameter portion 7
1 The inner peripheral surface (fixed portion 75) may be adhered, screwed, fitted with concavities and convexities, or attached by interposing an elastic body such as an O-ring.

FIG. 9 shows a second embodiment of the present invention. The present embodiment is a modification of the first embodiment, and is a ballpoint pen refill different from the first embodiment only in the shape of the ink containing tube 7. That is, the ink containing tube 7 is a straight pipe, and is specifically obtained by extrusion molding a transparent or translucent synthetic resin (for example, polypropylene, polyethylene, etc.). Since the ink containing tube 7 is an extruded body, it can be manufactured at a lower cost than the ink containing tube 7 by injection molding of the first embodiment.

The other structure of the second embodiment is the same as that of the first embodiment. That is, a pen tip 3 having the same structure as that of the first embodiment (a metal ballpoint pen tip 1 and a support cylinder 8 is fixed to the front portion of a holder 2 made of synthetic resin) at the tip opening of the ink containing tube 7. ) Is attached. Also,
The valve unit 4 having the same configuration as that of the first embodiment is press-fitted and fixed to the inner wall (fixing portion 75) of the front portion of the ink containing tube 7, and the tip of the valve unit 4 (regulation) is fixed to the rear end of the holder 2. The portion 52 side is abutted. In addition, the same ink 76 and backflow preventive agent 77 as those in the first embodiment are also accommodated in the ink accommodating tube 7. Further, the valve unit 4 is mounted at the same time when the holder 2 is mounted, from the opening of the front end of the ink containing tube 7 as in the first embodiment. Further, the valve unit 4 used in this embodiment may be the valve unit 4 shown in FIG. 5 or 8 in addition to FIG.

FIG. 10 shows a third embodiment. In this embodiment,
It is a modified example of the second embodiment (FIG. 9), and is a ballpoint pen refill different from the second embodiment only in the configuration of the pen tip 3. That is, the pen tip 3 is the ball-point pen tip 1 in which the ball receiving seat 13 and the ball holding portion are formed by cutting at the tip of the metal cylindrical body, and the tip of the tip holds the ball 14 rotatably. . This embodiment is a cutting type ball-point pen tip 1, and since the outer diameter is relatively large, the ink containing tube 7 is directly inserted without interposing another member such as the holder 2.
7 Can be attached to the tip, and the structure is simple.

The other structure of the third embodiment is the same as that of the second embodiment. That is, the same ink containing tube 7 as in the second embodiment.
An ink 76 and a backflow preventive agent 77, which are the same as those in the first and second embodiments, are housed inside the (straight pipe formed by extrusion molding of synthetic resin). In addition, the ink containing tube 7
The same valve unit 4 of the first and second embodiments is press-fitted and fixed to the front inner wall (fixed portion 75) of the above. Further, the valve unit 4 employed in this embodiment may be the valve unit 4 shown in FIG. 5 or 8 in addition to FIG.

FIG. 11 shows a fourth embodiment. In this embodiment,
It is a modification of the first embodiment (FIG. 1) and is an ink containing tube 7
The valve unit 4 is press-fitted and fixed to the inner wall (fixed portion 75) of the front small-diameter portion 71, and the valve unit 4 having the same configuration is also arranged in the tail plug 9. Specifically, the valve unit 4 has a tail plug 9 (tail plug 9 similar to FIG. 1).
It is press-fitted and fixed to the inner wall (fixed portion 96) of the air circulation hole 91. As the valve unit 4, the one shown in FIG. 5 or 8 in addition to FIG. 1 can be applied.

FIG. 12 shows the fifth embodiment. In this embodiment,
It is a modification of the second embodiment (FIG. 9) and is an ink containing tube 7
The valve unit 4 is press-fitted and fixed to the front inner wall (fixed portion 75) of the ink storage tube 7, and the rear end inner wall (fixed portion 7) of the ink containing tube 7 is fixed.
5) The valve unit 4 is directly press-fitted and fixed to 5).
The two valve units 4 have the same configuration (the valve cylinder 5 and the valve body 6 having the same shape and the same size).

With the arrangements shown in FIGS. 11 and 12, the two valve units 4 act simultaneously, so that more reliable backflow prevention is achieved. The valve unit 4 at the rear end portion of the ink containing pipe 7 has the ink 76 and the backflow preventive agent 7
The valve body 6 is located at the rear of the valve 7, and as soon as ink backflow occurs, the valve body 6 is brought into close contact with the valve seat 51, and the compressed air between the ink 76 and the backflow preventive agent 77 and the valve seat 51 is blocked. Prevent backflow.

[0050]

According to the first aspect of the invention, the material and shape of the valve chamber can be formed independently of the ink containing tube. As a result, a desired material and shape of the valve chamber can be set freely, and as a result, a ballpoint pen having a sufficient backflow prevention function, easy assembly, and a simple structure can be provided.

According to the second aspect of the present invention, a relatively soft material can be selected as the material of the valve chamber independently of the ink containing tube, and as a result, a soft valve seat and a soft and large amount of protrusion are restricted. The department can be set. The soft valve seat provides a reliable seal with the valve body.
Further, due to the soft restricting portion, when the valve body is press-fitted, the restricting portion is not damaged and a smooth insertability of the valve body is obtained. The large protrusion amount of the restricting portion ensures reliable contact with the valve element, and prevents the valve element from biting during the ink removal process by the centrifuge.

According to the third aspect of the invention, the ballpoint pen tip having a relatively small diameter can be attached by interposing the holder between the ink containing tube and the ballpoint pen tip.

According to the structure of claim 4, the rear end of the pen tip has a positioning function of the valve unit, so that the structure of the ink containing tube is simple and the manufacturing is easy. Further, when the holder is attached to the ink containing tube, the valve unit can be attached at the same time with the rear end of the holder and the tip of the valve unit in contact with each other, which facilitates the assembly.

According to the fifth aspect of the present invention, in addition to the prevention of ink backflow that occurs during storage with the pen tip facing upward, it is possible to more reliably prevent ink backflow that occurs due to a large momentary rearward impact. Further, since it is a valve unit, parts can be made common and quality control is fully performed, which is advantageous in manufacturing.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of the valve unit according to the first embodiment of the present invention.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a vertical sectional view showing an assembling process of the valve unit of FIG.

FIG. 5 is an enlarged vertical sectional view showing another example of the valve unit applied to the present invention.

6 is a sectional view taken along line BB of FIG.

FIG. 7 is an enlarged vertical sectional view showing another example of the valve unit applied to the present invention.

8 is a sectional view taken along line CC of FIG.

FIG. 9 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 10 is a vertical cross-sectional view showing a third embodiment of the present invention.

FIG. 11 is a vertical sectional view showing a fourth embodiment of the present invention.

FIG. 12 is a vertical sectional view showing a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ballpoint pen tip 11 Pipe 12 Tip edge 13 Ball receiving seat 14 Ball 2 Holder 21 Tip mounting hole 22 Locking wall 23 Communication hole 24 Mounting cylinder 25 Step 26 Ink flow hole 3 Pen tip 4 Valve unit 5 Valve cylinder 51 valve seat 52 regulating part 53 valve chamber 54 valve hole 55 ink through hole 56 chamfer 6 valve body 7 ink containing pipe 71 small diameter part 72 medium diameter part 73 large diameter part 74 fixing part 75 fixing part 76 ink 77 backflow preventive 8 support Cylinder 9 Tail plug 91 Air flow hole 92 Collar part 93 Mounting cylinder part 94 Small diameter cylinder part 95 Space part 96 Fixing part

Claims (5)

[Claims] 1. A fixing part (74) to which a pen tip (3) is fixed is provided on the inner wall of the front part of the ink containing tube (7), and inside the ink containing tube (7) behind the fixing part (74). Valve chamber (5
3 is a ball-point pen in which a valve body (6) for preventing backflow is movably accommodated in the valve chamber (53), and the valve body (6) comes in contact with the valve body (6) when moved forward. (52)
And a valve seat (51) for preventing ink flow due to contact of the valve body (6) when it is moved backward, the valve cylinder (5) having front and rear positions of the inner wall of the valve chamber (53). Tube (7)
The valve unit (4) is provided separately from the above, and the valve body (6) is housed in the valve chamber (53) of the valve cylinder body (5) to form a valve unit (4). A ball-point pen characterized in that it is arranged on the inner wall of the front part of 7). 2. The ball-point pen according to claim 1, wherein the valve cylinder body (5) is formed by integrally molding the regulating portion (52) and the valve seat (51) with the inner wall of the valve chamber (53) with a synthetic resin. . 3. The pen tip (3) has a ball (1
4) A ball-point pen tip (1) made of metal, which rotatably holds the ball-point tip, and a holder (2) made of synthetic resin, which holds the ball-point pen tip (1) at the front. Item 1. The ballpoint pen according to Item 1 or 2. 4. The ballpoint pen according to claim 1, 2 or 3, wherein the valve unit (4) is brought into contact with the rear end of the pen tip (3). 5. The ball-point pen according to claim 1, wherein the valve unit (4) is arranged on the inner wall of the rear end of the ink containing tube (7).