JPH1170775A - Ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ballpoint pen having a smooth operation of a valve and smooth writing by remarkably improving a dimensional accuracy of a valve chamber and optimizing a clearance between the valve and the chamber. SOLUTION: The ballpoint pen comprises a cylindrical body casing, and an ink cartridge. The cartridge has a pen tip, a connecting member, ink cylinder (ink housing member) and a spherical valve 8. The tip has a radially enlarged part 13 near a rear end opening of an ink guiding hole. And, a step part (valve locking part) is formed in the guiding hole. A part of the valve 8 is intruded into the part 13. In the case of moving the valve 8, the valve 8 is guided via the part 13 of the tip. The part 13 of the tip is formed by cutting or the like and has a remarkably high dimensional accuracy as compared with prior art.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen. INDUSTRIAL APPLICABILITY The present invention is particularly suitable as a configuration of a ballpoint pen containing a relatively low-viscosity ink such as an aqueous ink.

[0002]

2. Description of the Related Art Conventionally, ballpoint pens mainly contain oil-based ink. In recent years, instead of oil-based inks, those incorporating a lower-viscosity aqueous ink have been developed. By the way, the ballpoint pen using the water-based ink has a problem that the amount of the outflow of the ink is large and the dark line can be drawn, but the ballpoint pen is easily blurred. That is, the water-based ink has a lower viscosity than the oil-based ink, and the ink holding power of the ball storage chamber is weak. Therefore, if the pen tip is left with the tip up, the ink drops from the ball storage chamber toward the ink storage section. As a result, the ink in the ball storage chamber becomes empty, and the ink is faded during writing.

As a measure for preventing the backflow of ink, a ballpoint pen having a built-in valve is known (Japanese Utility Model Publication No. 4-52067, etc.). FIG. 15 is a cross-sectional view of a ballpoint pen with a built-in valve according to the related art. The ballpoint pen 100 of the prior art includes an ink core 1 in a main body shaft 101.
02 has been inserted. And the ink core 102
Is composed of a pen tip 105, an ink storage unit 106, a connection member 107, and a valve member 108. Here, the pen tip 105 is a member in which the writing ball 109 is built. The ink storage unit 10
Reference numeral 6 denotes a cylindrical member, in which a water-based ink is incorporated. The connection member 107 is a member that connects the pen tip 105 and the ink storage unit 106, and has a communication hole 11 at the center.
0 is provided. In the communication hole 110, a valve seat 111 and a projection 113 are provided.

[0004] The pen tip 105 is attached by being inserted into the distal end side of a connecting member 107.
On the other hand, the ink storage section 106 is mounted on the connecting member 107 so as to be exterior. In addition, the ballpoint pen 10 of the prior art
At 0, a valve chamber 115 is formed between the valve seat 111 and the projection 113 in the communication hole 110 of the connection member 107. A spherical valve element 108 is inserted into the valve chamber 115.

[0005] In the ballpoint pen 100 of the prior art, when the pen tip 105 is directed upward, the valve element 108 comes into contact with the valve seat 111 and closes the opening of the valve seat 111 as shown in FIG. Therefore, the backflow of the ink in the pen tip 105 is prevented. On the other hand, as shown in FIG.
When the valve 05 is turned downward, the valve element 108 leaves the valve seat 111, and the valve element 108 is locked by the projection 113. Therefore, the ink in the ink storage unit 106 is filled with the valve element 108 and the projection 11.
3 and flows into the pen tip tip 105 side.

[0006]

In the conventional ballpoint pen 100, the spherical valve body 108 moves in the valve chamber 115 by changing the attitude of the ballpoint pen 100 in the vertical direction, and the ink pen tip 105 side. Allow the outflow to
Backflow from the pen tip 105 toward the ink storage unit 106 is prevented. Therefore, blurring of ink at the time of writing is improved. However, prior art ballpoint pens 100
Since the outer wall of the valve chamber 115 is constituted by the inner wall of the communication hole 110 of the connecting member 107, the valve chamber 115
There is a drawback that the molding accuracy is low.

That is, the connecting member 107 is formed by injection molding, but since the projection 113 is provided on the inner peripheral surface of the hole, the portion of the valve chamber 115 is undercut. As a result, an excessive force is applied to the valve chamber 115 when the mold is removed, the dimensions are not stabilized, and the dimensional accuracy is limited. Under these circumstances, the conventional ballpoint pen 10
With the configuration of 0, it is difficult to optimally set the clearance between the valve chamber 115 and the valve element 108. Therefore, in the conventional ballpoint pen 100, the clearance is too small and the valve body 108 is caught in the middle of the movement, or conversely, the clearance is too large and the valve body 108 is loose and the valve seat 111 is
There was a problem that the adhesion with the film became insufficient.

Accordingly, the present invention focuses on the above-mentioned problems of the prior art, makes it possible to dramatically improve the dimensional accuracy of the valve chamber, achieves an appropriate clearance between the valve body and the valve chamber, and It is an object of the present invention to provide a ballpoint pen whose operation is smooth and writing is smooth.

[0009]

According to a first aspect of the present invention, there is provided a pen tip having a writing ball provided at a tip end thereof and an ink conducting hole provided in an axial direction. A tip, an ink storage section containing the ink, and a connecting member for connecting the nib tip and the ink storing section, wherein the connecting member is provided with a communication hole for communicating the ink storing section and the nib tip. In a ball-point pen in which a valve seat is provided in the communication hole and a valve body that comes into contact with the valve seat is stored so as to be movable in the axial direction, in the vicinity of the connection member side opening of the ink conduction hole of the pen tip, An enlarged diameter portion is provided, and a part or the whole of the valve body can be moved into the ink conducting hole. In the ink conducting hole, the valve body is locked, and a gap portion through which ink passes between the valve body and the valve body is provided. The valve body locking part to be formed When the tip is positioned upward, the valve body contacts the valve seat to prevent backflow of ink, and when the tip is positioned downward, the valve is partially or wholly A ballpoint pen, which moves into the ink passage hole, is locked by the valve body locking portion, and flows to the writing ball side via the gap.

In the ballpoint pen of the present invention, a part of the valve chamber is constituted by the rear end portion of the pen tip.
That is, in the ball-point pen of the present invention, the enlarged diameter portion is provided near the opening of the pen tip tip on the connection member side of the ink conduction hole, and a part or all of the valve body can be moved into the ink conduction hole. Further, a valve body locking portion for locking the valve body is provided in the ink conducting hole of the pen tip tip. Therefore, the valve element moves between the valve seat provided in the communication hole of the connection member and the valve element locking portion provided in the ink conduction hole, and the ink conduction hole itself of the pen tip tip functions as a valve chamber. I do. More specifically, in the present invention, the enlarged diameter portion of the ink conduction hole and the valve body locking portion function as a valve chamber. Here, since the pen point tip is generally formed by cutting or the like, the limit of the forming accuracy is much higher than that of the connecting member. Therefore, the enlarged diameter portion of the pen tip can be formed with high dimensional accuracy, and an appropriate clearance can be given to the valve body. Further, in the present invention, when the valve body is locked by the valve body locking portion, a gap is formed between the valve body locking portion and the valve body.
Therefore, when the pen tip is positioned downward,
The valve body is locked by the valve body locking portion, and the ink flows to the writing ball via the gap.

According to a second aspect of the present invention, the above-described invention is further improved, wherein the pen tip is inserted into the communication hole of the connecting member, and the inner surface of the communication hole is provided between the valve seat and the tip of the pen tip. 2. The ball-point pen according to claim 1, wherein the inner diameter of the end portion is substantially equal to the inner diameter of the enlarged portion of the pen tip.

The ballpoint pen according to the present invention is such that the inside diameter of the connecting member side of the parts constituting the valve chamber is substantially equal to the inside diameter of the enlarged diameter part of the pen tip, thereby further stabilizing the operation of the valve body. is there. That is, in the ballpoint pen of the present invention, the inner diameter of the connection member side is substantially equal to the inner diameter of the enlarged diameter portion of the pen tip. Therefore, the step between the enlarged portion of the pen tip and the inner periphery of the connecting member is reduced, and the barrier when the valve element enters the enlarged portion of the pen tip is reduced. As a result, the valve element smoothly moves between the enlarged diameter portion of the pen tip and the valve seat.

According to a third aspect of the invention in which the shape of the valve body is embodied, the valve body is a ball-point pen according to the first or second aspect, wherein the valve body is a sphere.

According to a fourth aspect of the present invention, wherein the valve body locking portion is embodied, a step portion is provided at a boundary portion between the enlarged diameter portion of the ink conduction hole and another portion, and the valve body is formed by the step portion. The ballpoint pen according to any one of claims 1 to 3, wherein a locking portion is formed, a groove is provided in the step portion, and a gap is formed by the groove. The step portion may have a vertical wall shape or an inclined wall shape.

According to a fifth aspect of the present invention, wherein the shape of the groove is further embodied, the groove has a cross-sectional shape of any one of a triangle, a circle, and a square, and a plurality of grooves are provided in the step portion. A ballpoint pen according to claim 4. It is sufficient that the groove communicates with the enlarged diameter portion of the ink conducting hole and the portion on the writing ball side.

[0016]

Embodiments of the present invention will be described below. FIG. 1 is a sectional view of a ballpoint pen according to the embodiment of the present invention. FIG. 2 is a perspective view of the tip end of the pen tip of the ballpoint pen of FIG. FIG. 3 is a cross-sectional perspective view of a pen tip tip rear end, a valve body, and a connection member front end of the ballpoint pen of FIG. FIG. 4 is an enlarged cross-sectional view of a joint portion between the pen point tip and the connection member. FIG. 5 is a cross-sectional view of FIG.
It is A sectional drawing. FIG. 6 is a sectional view taken along line BB of FIG.
FIG. 7 is an enlarged cross-sectional view of a joint portion between the pen tip and the connection member in a state where the pen tip is directed upward. FIG. 8 is an enlarged cross-sectional view of a joint portion between the pen tip and the connecting member in a state where the pen tip is directed downward. FIG. 9 is an enlarged cross-sectional view of a joint between a pen tip of a ballpoint pen and a connecting member according to another embodiment of the present invention, a cross-sectional view taken along line CC of the joint, and an enlarged cross-sectional view of a modification of the joint. FIG. 10 is an enlarged cross-sectional view of a joint portion between a pen point tip of a ball-point pen and a connecting member according to another embodiment of the present invention, and a DD cross-sectional view thereof. FIG. 11 is a cross-sectional perspective view of a pen tip tip rear end portion, a valve body, and a connection member front end portion of a ballpoint pen according to another embodiment of the present invention. FIG.
2 is an enlarged sectional view of a joint portion between the pen tip tip and the connecting member and an AA sectional view thereof. 13 and 14
Is an enlarged cross-sectional view of a joint portion between a pen tip of a ball-point pen and a connecting member according to another embodiment of the present invention, and FIG.
It is -C sectional drawing.

1 to 8, reference numeral 1 denotes a ballpoint pen according to an embodiment of the present invention. Ballpoint pen 1 of the present embodiment
Is the same as that of the prior art, and has a cylindrical main body shaft 2.
And an ink core 3. The ink core 3 includes a pen tip 5, a connection member 6, an ink cylinder (ink storage member) 7, and a spherical valve body 8.

To explain sequentially, the pen point tip 5 is a member having a writing ball 10 provided at the tip, and is made by cutting a metal material such as free-cutting steel. The outer shape of the nib tip 5 is almost the same as that of a known tip,
7 is conical and the rear side 18 is cylindrical.
A step 19 is provided at the rear end side, and the rear end side of the step 19 is made slightly smaller in diameter. Further, the front end portion on the rear end side is provided with a tapered shape so that it can be easily inserted into the connection member 6. The presence or absence of the step 19 is optional.

The internal shape of the pen point tip is as shown in FIG. 1. The tip portion has a ball storage chamber in which a writing ball 10 is stored, and an ink conducting hole 12 communicating from the ball storage chamber to the rear end side. Is provided.

It should be noted that the pen tip 5 employed in the present invention has an enlarged diameter portion 13 in the vicinity of the rear end opening of the ink passage hole 12 and the inside of the ink passage hole 12. Is formed with a stepped portion (valve body locking portion) 15. That is, as shown in FIGS. 3 and 4, the rear end portion of the ink passage hole 12 has a larger inner diameter than the other portion of the ink passage hole 12 (the pen tip insertion side). Enlarged part 1
3 has an inner diameter D of about 70% to 1
It is set to about 50%. A desirable range of the inner diameter D of the enlarged diameter portion 13 is about 110% of the diameter of the valve body 8 to 150%.
%. The lower limit of the desirable range of the inner diameter D is 110
The reason is that it is desirable that at least half of the valve body 8 can be immersed in the enlarged diameter portion 13. The reason why the upper limit is 150% is that if the inner diameter D is larger than this, the enlarged diameter portion 13 becomes larger. This is because the clearance between the valve body 8 and the valve body 8 becomes too large.

It is recommended that the axial length h of the enlarged diameter portion 13, that is, the depth of the enlarged diameter portion 13 be in the range of 30% to 90% of the diameter of the valve element 8. Further, the inside diameter d of the other portion of the ink passage hole 12, that is, the inside diameter of the center opening when the pen tip 5 is viewed from the rear end side is in the range of 70% to 90% with respect to the diameter of the valve body 8. It is recommended that The step portion 15 may be stood perpendicularly to the inner wall of the enlarged diameter portion 13, or may have a certain degree of inclination and a mortar shape as viewed from the rear end side. In the ballpoint pen 1 of the illustrated embodiment, the step portion 1
5 has an inclination of about 120 ° with respect to the inner wall of the enlarged diameter portion 13, and in a specific range, about 110 ° to 130 °.

In short, it is important that the shape and dimensions of each part of the enlarged diameter portion 13 are such that a part of the valve element 8 can enter the enlarged diameter portion 13 as shown in FIG. . Here, it is desirable that the amount of the valve body 8 entering the enlarged diameter portion 13 is equal to or larger than the equator when the valve body 8 is regarded as the earth.
That is, the amount of entry H of the valve element 8 (see FIG. 4)
Is desirably 50% or more of the diameter. In addition, valve body 8
The most recommended value of the penetration amount H is about 60% to 100% of the diameter of the valve body 8. The above-mentioned recommended range of the penetration amount H is not limited, and may be about 40% of the diameter of the valve body 8, and conversely, the entirety of the valve body 8 is immersed in the enlarged diameter portion 13 so as to be 120%. There may be a surplus state. When the amount of entry H is equal to or less than the equator when the valve element 8 is regarded as the earth, such as when the amount of entry H is about 40% of the diameter of the valve element 8, the valve element 8 moves quickly. There are advantages. When the valve element 8 is in the enlarged diameter portion 13, the valve element 8 comes into contact with a part of the step portion 15 and is prevented from moving toward the distal end. It is necessary to ensure a clearance through which ink passes between the inner circumferences of the diameter portion 13.

Another characteristic configuration is that the step portion 1
5 is that a kerf (void) 16 is provided.
In the present embodiment, the cut grooves 16 have one triangular shape as shown in FIGS. Kerf 1
The axial length of the valve body 6 is about one third of the diameter of the valve body 8 as shown in FIGS. Further, the depth of the cut groove 16 gradually decreases from the enlarged diameter portion 15 toward the writing ball 10.

The connecting member 6 is made by injection molding using a thermoplastic resin such as polypropylene resin as a raw material, and its outer shape is not much different from that of a known member. That is, the connecting member 6 has a conical shape on the tip end 20 side. The rear end side has a two-stage cylindrical shape, and a large-diameter portion 21 and a small-diameter portion 22 are sequentially provided. At the center of the connection member 6, a communication hole 23 penetrating in the axial direction is provided. A valve seat 25 is provided at an intermediate portion of the communication hole 23. The shape and dimensions of the valve seat 25 are the same as those known in the art. A positioning step 31 is provided at the tip end of the communication hole 23.

A characteristic part of the structure of the connecting member 6 is that the inner diameter of the inner peripheral surface of the communication hole 23 toward the distal end from the valve seat 25 is small. The inside diameter of the small diameter portion 28 is equal to the inside diameter D of the large diameter portion 13 of the pen tip 5 described above. The position of the small diameter portion 28 corresponds to a position between the rear end of the pen tip 5 and the valve seat 25 when the pen tip 5 is inserted.

The valve body 8 is a sphere made of a material which is hardly rusted such as stainless steel, cemented carbide or ceramic and has a certain weight.

The ink cylinder 7 is made by extrusion molding using a polyethylene resin, a polypropylene resin or the like as a material, and is filled with an aqueous ink.
The rear end of the aqueous ink is sealed with a gel sealing member such as polybutene.

As shown in FIG. 1, the ink core 3 is formed by connecting a pen tip 5 and an ink cylinder 7 via a connecting member 6, and the pen tip 5 is connected to a communication hole 23 of the connecting member 6. The ink cylinder 7 is provided on the small diameter portion 22 at the rear end of the connection member 6. When the pen tip 5 is inserted, the step 19 is positioned in contact with the step 31 of the connecting member 6. In a state where the pen tip 5 is inserted, the rear end of the pen tip 5 is located at a position close to the small diameter portion 28 of the connection member 6 as shown in FIG.

The valve element 8 is inserted in the connecting member 6 between the step 15 of the pen tip 5 and the valve seat 25 so as to be movable in the axial direction. That is, in the ball-point pen 1 of the present embodiment, the front portion of the valve seat 25 of the communication hole 23 of the connecting member 6 and the enlarged diameter portion 13 of the pen tip 5 are close to each other, and the two have a larger inner diameter than other portions. Are formed. In the ballpoint pen 1 of the present embodiment, a space having an inner diameter larger than that of the other parts is made to function as the valve chamber 27, and the valve body 8 is disposed inside.

The ballpoint pen 1 according to the present embodiment is provided on the large diameter portion 21 of the connection member 6 of the ink core 3 described above.

Next, the operation of the ballpoint pen 1 according to the present embodiment will be described. The ballpoint pen 1 of the present embodiment is
When the valve body 8 is oriented upward, as shown in FIG.
5 in a liquid-tight manner, and the backflow of ink from the pen tip 5 is prevented.

Next, when the ball-point pen 1 is turned upside down for writing and the pen tip 5 is oriented downward, the valve body 8 drops by gravity, and the enlarged portion of the pen tip 5 is used as shown in FIG. Move to 13 smoothly. That is, the pen tip 5
The rear end side is located at a position close to the small-diameter portion 28 of the connection member 6 as described above, and the inner diameter of the small-diameter portion 28 is equal to the inner diameter D of the large-diameter portion 13. The step at the connection with the 6 side is small. Therefore, the valve element 8 is
It moves smoothly from the 5 side to the enlarged diameter section 13 side. Then, as shown in FIG. 8, a part of the valve element 8 enters the enlarged diameter portion 13 and comes into contact with the step portion 15 of the pen tip 5.

Here, the step 15 of the pen tip 5 is
Since the cut groove 16 is provided as described above, a gap 33 as shown in FIG. 8 is formed between the step portion 15 and the valve element 8. In addition, there is a sufficient clearance between the inner peripheral wall of the enlarged diameter portion 13 and the valve body 8 for the ink to flow. Therefore, the ink in the ink cylinder 7 is filled with the inner peripheral wall of the enlarged diameter portion 13 and the valve body 8.
, Flows into the pen tip 5 via the gap 33, and is supplied to the writing ball 10.

When the pen tip 5 is turned up again after writing, the valve body 8 separates from the step portion 15 and comes into contact with the valve seat 25 as shown in FIG. When moving, the valve element 8 is guided by the enlarged diameter portion 13 of the pen tip 5. Here, the enlarged diameter portion 13 of the pen point tip 5 is made by cutting or the like, and the dimensional accuracy is remarkably higher than the conventional technology, and the clearance between the inner wall of the enlarged diameter portion 13 and the valve element 8 is appropriate. It is. Therefore, the valve body 8 moves smoothly and contacts the valve seat 25 to seal the opening of the valve seat 25.

In the above-described embodiment, the cut grooves 16 provided in the step portion 15 in the pen tip 5, that is, the grooves forming the voids are provided at equal intervals, but the number is arbitrary, and the number is arbitrary. It may be of the order of 10 or more than 10. As a design guide, it is desirable to take care that a void having as large an area as possible is formed when the valve element 8 comes into contact with the stepped portion 15. I can say.

The sectional shape of the cut groove is not limited to a triangle, and may be a square cut groove 51 as shown in FIG. A semi-circular shape is also recommended in consideration of ease of processing. Generally, it is desirable that the length of the kerf is longer, and the length of the kerf is determined depending on the processing method.
Therefore, the length of the kerf may be relatively short as in the example shown in FIG. 4 or longer than the kerf 51 in FIG. The shape of the end portion of the cut groove 51 may be a stepped shape as shown in FIG. 9B, but it is recommended that the cut groove 51 has a tapered shape as shown in FIG. 9C. That is, by forming the portion in a tapered shape, the air is easily released, and the flow of the ink becomes smoother. Further, by forming the portion in a tapered shape, an excessive load can be released during processing, and deformation can be prevented.

From the viewpoint of facilitating the escape of air, it is preferable that there is no gap between the tip of the pen tip 5 and the connecting member 6. In other words, from the viewpoint of facilitating the escape of air, it is recommended that the tip of the pen tip 5 and the connecting member 6 come into direct contact as shown in FIG. 9D. As shown in FIG. 9D, when a configuration is adopted in which the tip of the pen tip 5 is directly in contact with the connection member 6, the axial positioning when the pen tip 5 is inserted by the contact between them is performed. The pen tip 5 and the connecting member 6
It is not necessary to provide the step portion 19 and the step portion 31 at the bottom.

In the embodiment shown in FIG. 9 and FIG. 10 to be described later, the same members as those in the previous embodiment are denoted by the same reference numerals, and a detailed description thereof will be omitted.

When the ink conducting hole 12 of the pen tip 5 is small, it is also recommended to provide a groove between the step portion and the valve body 8 by providing an arrow-shaped groove. FIG. 10 shows an example in which an arrow-shaped groove 40 is provided. That is, when the ink conducting hole 12 is small as shown in FIG. 10, the opening of the groove is closed by the valve 8 even if the groove is provided in the axial direction. Therefore, a radial groove 40 is provided on the contact surface of the step portion 41, and the valve body 8 is designed to contact the step portion over this groove.

In each of the above-described embodiments, the example in which the tapered shape is provided on the rear end side of the pen point tip 5 is illustrated.
The presence or absence of the tapered shape of this portion is arbitrary, and the rear end side of the pen point tip 5 may have a so-called sloping shape. FIG. 11 is a cross-sectional perspective view of a portion corresponding to FIG. 3 of the first embodiment in the case where the configuration without the tapered shape is adopted, and FIG. FIG. 6 is a sectional view of a portion corresponding to FIGS. 4 and 5 of the embodiment. FIG. 13 shows an example in which the basic configuration is the same as that of the embodiment shown in FIG. 9 and the tapered shape on the rear end side of the pen tip 5 is eliminated. FIG. 14 shows an example in which the basic configuration is the same as that of the embodiment shown in FIG. 10 and the tapered shape on the rear end side of the pen tip 5 is eliminated. When the pen point tip 5 having no tapered shape is adopted, there is a disadvantage that the insertion into the connecting member 6 becomes somewhat difficult, but the pen point tip 5
Since the gap between the outer periphery of the connecting member 6 and the inner peripheral portion of the connecting member 6 is reduced, the problem that air stays in the portion is eliminated. That is, when a tapered shape is provided at the rear end of the nib tip 5 as in the embodiment of FIGS.
As shown in 7, 8, 9, and 10, an annular gap is formed between the outer peripheral surface of the tapered portion and the inner peripheral surface of the connection member 6. Then, air may accumulate in this gap, and there is a concern that the flow of ink may be obstructed. In contrast, if a pen tip having no tapered shape at the rear end as shown in FIGS.
There is no gap between the inner peripheral portion of the connecting member 6 and air does not accumulate.

In the above-described embodiment, the small-diameter portion 28 is provided on the inner peripheral surface of the communication hole 23 at a position from the valve seat 25 toward the distal end, but a rib extending in the axial direction is provided at the portion. It is also recommended that the inscribed circle is substantially coincident with the inner diameter of the enlarged diameter portion 13.

The enlarged diameter portion 13 and the cut groove 1 of the pen tip 5
The manufacturing method of No. 6 is arbitrary, and various methods including a known method can be adopted. For example, a prepared hole having a diameter corresponding to the ink conducting hole 12 is made in the in-process product of the nib tip 5, and then the opening portion is widened with a drill or a reamer having a diameter corresponding to the inner diameter of the enlarged diameter portion 13 to enlarge the enlarged diameter portion. 13 can be considered. Conversely, the enlarged diameter portion 13 may be provided first with a drill having a diameter corresponding to the inner diameter of the enlarged diameter portion 13, and a hole corresponding to the ink conducting hole 12 may be provided at the center. In addition, the cutting groove 16 is used to cut a tool such as a broach from the enlarged diameter side to the stepped portion 15.
And the inside of the step 15 is scraped in a groove shape. Further, in the case where an arrow groove-shaped groove 40 as shown in FIG. 10 is provided, a tool having a blade on the end face side is pressed against the step portion 15 in the same manner as an arrow groove normally provided in a ball storage chamber of a writing ball. Can be provided. Regardless of whether the groove 16 is provided or the arrow-shaped groove is provided, the enlarged diameter portion 13 functions as a tool guide when forming the groove. There is little blurring.

[0043]

The ball-point pen of the present invention has a portion of the valve chamber formed by the rear end of the pen tip, and the enlarged diameter portion of the pen tip functions as a valve chamber. Therefore, an appropriate clearance can be given to the valve element, and the operation of the valve element is smooth. Therefore, in the ballpoint pen of the present invention, the backflow of the ink is prevented, and the outflow of the ink to the writing ball side is smooth and the writing quality is good.

In the ballpoint pen according to the second aspect of the present invention, the inside diameter of the portion forming the valve chamber in the inner surface of the communication hole is substantially equal to the inside diameter of the enlarged diameter portion of the pen tip. The step between the enlarged diameter portion and the inner periphery of the connection member is small.
Therefore, in the ballpoint pen of the present invention, the movement of the valve body is further smoothed, and the effect of preventing the backflow of ink and the effect of smoothly flowing out of ink are high.

[Brief description of the drawings]

FIG. 1 is a sectional view of a ballpoint pen according to an embodiment of the present invention.

FIG. 2 is a perspective view of a rear end of a pen tip of the ballpoint pen of FIG. 1;

FIG. 3 is a cross-sectional perspective view of a pen tip tip rear end portion, a valve body, and a connection member front end portion of the ballpoint pen of FIG. 1;

FIG. 4 is an enlarged cross-sectional view of a joint portion between a pen point tip and a connection member.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a sectional view taken along line BB of FIG. 4;

FIG. 7 is an enlarged cross-sectional view of a joint portion between the pen tip and the connection member in a state where the pen tip is oriented upward.

FIG. 8 is an enlarged cross-sectional view of a joint portion between the pen tip and the connecting member in a state where the pen tip is directed downward.

FIG. 9 is an enlarged sectional view of a joint between a pen tip of a ballpoint pen and a connecting member according to another embodiment of the present invention, a sectional view taken along the line CC of FIG. 9 and an enlarged sectional view of a modification of the joint.

FIG. 10 is an enlarged cross-sectional view of a joint portion between a pen tip of a ball-point pen and a connecting member according to another embodiment of the present invention, and a DD cross-sectional view thereof.

FIG. 11 is a cross-sectional perspective view of a pen tip tip, a valve body, and a connecting member tip of a ballpoint pen according to another embodiment of the present invention.

FIG. 12 is an enlarged cross-sectional view of a joint portion between a pen tip tip and a connection member and an AA cross-sectional view thereof.

FIG. 13 is an enlarged cross-sectional view of a joint portion between a pen tip of a ball-point pen and a connecting member according to another embodiment of the present invention, a cross-sectional view taken along the line CC of FIG.

FIG. 14 is an enlarged cross-sectional view of a joint portion between a pen tip of a ball-point pen and a connecting member according to another embodiment of the present invention, and a CC cross-sectional view thereof.

FIG. 15 is a cross-sectional view of a conventional ballpoint pen with a built-in valve.

[Description of Signs] 1 Ballpoint pen 2 Body shaft 3 Ink core 5 Pen tip 6 Connection member 7 Ink cylinder (ink storage member) 8 Valve body 10 Writing ball 12 Ink conduction hole 13 Enlarged diameter part 15 Step part (Valve body member) Stop portion) 16 Cut groove (gap) 23 Communication hole 33 Gap D Inner diameter of enlarged diameter portion H Entrance amount of valve body

Claims (5)

[Claims] 1. A pen tip having a writing ball built in at a tip thereof and having an ink conducting hole communicating in the axial direction, an ink storage section storing ink, the pen tip tip and the ink storage section. A connection member that connects the ink storage unit and the pen tip, and a valve seat that is provided in the communication hole and abuts on the valve seat. In the ball-point pen which is accommodated so as to be movable in the axial direction, an enlarged diameter portion is provided near the opening of the pen tip tip on the connecting member side of the ink conducting hole, and a part or all of the valve element moves into the ink conducting hole. It is possible to provide a valve element locking portion that locks the valve element in the ink conduction hole and forms a gap through which ink passes between the valve element and the valve element. The valve body comes into contact with the valve seat When the tip of the pen tip is positioned downward, part or all of the valve body moves into the ink conducting hole and is locked by the valve body locking portion, and writing is performed via the gap. A ballpoint pen characterized by flowing to a ball for use. 2. The pen tip is inserted into a communication hole of the connecting member, and the inner diameter of the valve seat and the rear end portion of the pen tip on the inner surface of the communication hole is the inner diameter of the enlarged portion of the pen tip. The ballpoint pen according to claim 1, wherein 3. The ballpoint pen according to claim 1, wherein the valve body is a ball. 4. A step portion is provided at a boundary portion between the enlarged diameter portion of the ink conduction hole and another portion, a valve element locking portion is formed by the step portion, and a groove is provided at the step portion. 4. The ballpoint pen according to claim 1, wherein a void is formed by the groove. 5. The ballpoint pen according to claim 4, wherein the groove has a cross-sectional shape of any one of a triangle, a circle, and a rectangle, and a plurality of grooves are provided in the step portion.