JP2004130651A - Ball-point pen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure the secure adhesion of a joint part for a metallic ball-point pen tip by appropriately setting the surface roughness of the joint part, in the ball-point pen of the structure that a part of the metallic ball-point pen tip is forcibly fitted into the apex of a resin ink storage tube and the joint part is thermally melted or softened/closely bonded. <P>SOLUTION: This ball-point pen 10 is structured of the resin ink storage tube 20 storing an ink 25 internally and the metallic ball-point pen tip 30 fitted with a part of the rear end side forcibly fitted into the apex side of the ink storage tube 20. The ball-point pen tip 30 and the ink storage tube 20 are melted or softened/closely bonded together by heating up the joint part between the ball-point pen tip 30 and the ink storage tube 20. The arithmetic average roughness of the surface of the part where the rear end of the bal1-point pen chip 30 is forcibly fitted is 0.5 to 3.0 μm. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ball-point pen in which a part of a metal ball-point pen tip is press-fitted to the tip of a resin ink container tube.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, ballpoint pens in which a part of a metal ballpoint pen tip is press-fitted to the tip of a resin ink container tube have been widely manufactured and sold.
In such a ball-point pen, since the rear end of the ball-point pen tip is press-fitted into the front end of the ink storage tube, the outer diameter of the rear end of the ball-point tip is larger than the inner diameter of the front end of the ink storage tube. I have. It is known that, after press-fitting, the joined portion is heated and melted or softened so that the ink container tube and the ball-point pen tip are more tightly joined.
[0003]
Particularly, in a ball-point pen (a so-called pressurized ball-point pen) in which a pressurized gas is sealed in the rear end portion of the ink storage tube to give a force for pushing out the ink in the front end direction, a ball-point pen tip attached to the ink storage tube Also, pressure is applied in the tip direction. For this reason, in the case of a pressurized ballpoint pen, it is necessary to more closely join the ballpoint pen tip and the ink storage tube. Therefore, in the pressurized ball-point pen, importance is attached to melting or softening adhesion due to a rise in the temperature of the joint between the ink storage tube and the ball-point pen tip.
[0004]
Here, the ink storage tube is formed of a single ink tube, and a so-called joint portion for directly holding the ballpoint pen tip is formed separately from the ink tube, and finally formed in the ink tube. This includes a part in which the joint portion is joined to form an ink storage tube.
As a prior art, a method of manufacturing a pressurized ball-point pen that allows direct observation of ink consumption is disclosed in Patent Document 1 below, and a method of mounting a writing tool chip by welding is disclosed in Patent Document 2 below.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 50-96334 [Patent Document 2]
JP-A-56-44694
[Problems to be solved by the invention]
As described above, when a resin ink container is melted or softened and adhered around a metal ballpoint pen tip, it is desirable that the melted or softened resin be well entangled with the joint portion of the ballpoint pen tip. Therefore, the periphery of the joint portion of the ballpoint pen tip needs to have a certain surface roughness. However, there is no technology that has considered this point.
[0007]
In view of the above, the present invention provides a ballpoint pen in which a part of a metal ballpoint pen tip is press-fitted and mounted at the tip of a resin ink storage tube, and the bonding portion is heated and melted or softened and adhered. It is an object of the present invention to ensure that the joints are brought into close contact by appropriately setting the surface roughness. It is another object of the present invention to increase the durability against the pressure of the sealed gas and to secure the airtightness, particularly in a pressurized ballpoint pen, by ensuring that the joints are brought into close contact with each other.
[0008]
[Means for Solving the Problems]
In view of the above problems, the present invention provides a resin ink storage tube 20 for storing ink 25 therein, and a metal that is partially press-fitted to the front end side of the ink storage tube 20 and mounted on the front end side. A ball-point pen 10 provided with a ball-point pen tip 30 made of a resin, wherein the ball-point pen tip 30 and the ink storage tube 20 are melted or softened and adhered by increasing the temperature of the joint between the ball-point tip 30 and the ink storage tube 20. In addition, the arithmetic mean roughness of the surface of the portion at the rear end of the ball-point pen tip 30 which is press-fitted is not less than 0.5 μm and not more than 3.0 μm.
[0009]
Here, when the arithmetic mean roughness of the surface of the portion of the ball-point pen tip 30 to be press-fitted at the rear end is less than 0.5 μm, even if the resin of the ink containing tube 20 is welded by heating, the ball-point tip 30 It becomes difficult for the molten resin to enter the minute concave portions on the surface. Therefore, the biting of the ink containing tube 20 to the ball-point pen tip 30 becomes poor, and the force of the ink containing tube 20 holding the ball-point pen tip 30 becomes weak.
[0010]
On the other hand, if the arithmetic mean roughness of the surface of the portion of the ball-point pen tip 30 to be press-fitted is more than 3.0 μm, the inner surface of the ink-pipe 20 is easily damaged when pressed into the ink container 20. As a result, cracks are likely to occur. Further, it is rather difficult for the molten resin to reach the bottom of the concave portion on the surface of the ballpoint pen tip 30, so that the welding is incomplete. In particular, in the case where a pressurized gas is sealed at the rear end side of the ink storage tube 20 in the ink storage tube 20, the cause of gas leakage at the time of pressurization may be caused by incomplete welding. Become.
[0011]
Further, a joint 22 member provided separately is provided at a tip portion of the ink storage tube 20, and the ballpoint pen tip 30 may be directly connected to the joint 22 member at the tip of the ink storage tube 20.
In the case of a pressurized ball-point pen, since it is necessary to more securely join the ink storage tube 20 and the ball-point pen tip 30 by welding, the arithmetic average roughness of the surface of the portion at the rear end of the ball-point pen tip 30 that is press-fitted is fitted. Is desirably 0.5 μm or more and 1.5 μm or less.
[0012]
Here, “heating” refers to increasing the temperature of the junction. For example, it is possible to generate an eddy current on the surface of the ballpoint pen tip 30 by induction heating and generate heat by a resistor to raise the temperature.
Therefore, if the arithmetic mean roughness of the surface of the portion where the ball-point pen tip 30 is press-fitted at the rear end is within the above-described range, it is possible to reliably bring the joint portion between the ball-point pen tip 30 and the ink storage tube 20 into close contact. Become.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 7 schematically illustrate an embodiment of the present invention, and are not necessarily based on an accurate scale.
(1) First Embodiment The ballpoint pen 10 according to the first embodiment is one in which a pressurized gas is sealed inside the ink containing tube 20. In the present embodiment, the refill 11 shown in FIG. 1 is employed. That is, the ink storage tube 20 includes an ink storage unit 21 that directly stores ink, and a joint 22 that is attached to a tip of the ink storage unit 21. Further, a ball-point pen tip 30 is attached to the tip of the joint 22 of the ink storage tube 20. Further, a tail plug 24 is attached to the rear end of the ink storage tube 20.
[0014]
(1-1) Ink storage tube 20
In the ink container 20, the ink container 21 is formed of a cylindrical tube made of ethylene-vinyl alcohol copolymer (EVOH). The ink container 21 is filled with oil-based ink as the ink 25.
The joint 22 of the ink container 20 is formed of EVOH. The inner diameter D2 of the joint 22 is 1.84 mm. An approach 23 having a slightly enlarged inner diameter is formed at the distal end of the joint 22 (see FIG. 2A). The length L2 of this approach 23 portion is 0.1 mm.
[0015]
(1-2) Ballpoint pen tip 30
The ballpoint pen tip 30 is formed by cutting a cylindrical material made of stainless steel, and has an outer diameter as shown in FIG. 2A.
Specifically, the distal end side of the columnar material is cut into a conical shape to form the tapered portion 31. Then, a ball house (not shown) is formed by cutting the inside on the tip side. On the other hand, the outer diameter of the rear end side of the columnar material is reduced by cutting to form the press-fit portion 32. The outer diameter D1 of the press-fit portion 32 is 1.9 mm.
[0016]
The arithmetic average roughness (Ra) of the outer periphery of the press-fitting portion 32 is measured using a non-contact three-dimensional measuring device (Mitaka Optical, NH-3) at a measuring pitch of 5 μm, a measuring distance of 2 mm, and a cutoff value of 0.8 mm. It was measured under the conditions. According to this, Ra was 1.47 μm.
The rear end of the press-fitting portion 32 is chamfered for convenience of insertion at the time of press-fitting. The length of the portion of the press-fitting portion 32 excluding the chamfered portion, that is, the length L1 of the portion holding the outer diameter D1 is 3.25 mm.
[0017]
Hereinafter, a back hole (not shown) is formed from the rear end side of the columnar material to the middle part. Then, an ink hole (not shown) connecting the ball house and the back hole is formed from the tip end side, and several grooves (not shown) (not shown) penetrate radially around the ink hole.
After the cemented carbide ball 34 is inserted into the ball house, the tip of the tapered portion 31 is crimped inward to form the caulked portion 33.
[0018]
The overall length of the ballpoint pen tip 30 thus formed is 12.3 mm.
(1-3) Manufacturing Process of Refill 11 The manufacturing process of the refill 11 is as follows.
First, the ink container 21 is filled with the ink 25. On the other hand, the press-fitting portion 32 of the ballpoint pen tip 30 is press-fitted into the tip of the joint 22 (see FIG. 2B). Then, the rear end portion of the joint 22 into which the ball-point pen tip 30 is press-fitted is press-fitted into the front end of the ink container 21.
[0019]
Here, assuming that the length of the portion of the press-fitting portion 32 of the ball-point pen tip 30 where the outer diameter holds D1 is L1, and the length of the approach 23 of the joint 22 of the ink containing tube 20 is L2. In the process of press-fitting, the length (press-fitting length) L of the portion that deformed the inner wall of the ink storage tube 20 is:
L = L1-L2 = 3.25-0.1 = 3.15
Becomes 3.15 mm (see FIG. 2C).
[0020]
After the ball-point pen tip 30 is press-fitted, the temperature of the junction between the ball-point pen tip 30 and the joint 22 of the ink storage tube 20 is increased to 200 ° C. by induction heating, and the melted adhesion is achieved. Then, centrifugal processing is performed so that centrifugal force is applied in the direction of the tip of the ballpoint pen tip 30 to remove bubbles remaining in the refill 11.
Thereafter, the refill 11 is moved into a pressurized atmosphere of 3 atm (absolute pressure) filled with nitrogen gas, and then a tail plug 24 is pressed into the rear end, and this is melted and fixed. As a result, the pressurized nitrogen gas is sealed inside the ink container 20 behind the ink 25.
[0021]
The front half of the refill 11 thus manufactured is inserted into the front shaft 12 which is internally threaded at the rear end. Then, the rear shaft 13 and the front shaft 12 are screwed together while the latter half portion is inserted into the rear shaft 13 having a male screw cut outside the front end portion. Then, the cap 14 is attached to the tip, and the ballpoint pen 10 is completed (see FIG. 3).
In addition to the manner in which the tail plug 24 is attached to the rear end of the ink storage tube 20 and hermetically sealed as in the case of the above-described refill 11, the ink storage tube 20 is further compressed in a pressurized atmosphere by a tube having a larger diameter. An embodiment in which the tube is covered and hermetically sealed is also possible.
[0022]
(2) Second Embodiment In a ball-point pen according to a second embodiment, the inside of the ink container 20 has an open structure. In the present embodiment, the refill 11 shown in FIG. 4 is employed. That is, the ink storage tube 20 includes an ink storage unit 21 that directly stores the ink 25 and a joint 22 that is attached to a tip of the ink storage unit 21. Further, a ball-point pen tip 30 is attached to the tip of the joint 22 of the ink storage tube 20. Further, an ink follower 26 is provided at the rear end of the ink 25 to prevent the ink 25 from flowing backward.
[0023]
(2-1) Ink storage tube 20
The ink container 21 of the ink container 20 is formed of a polypropylene cylindrical tube. The ink container 21 is filled with a so-called medium viscosity aqueous gel ink as the ink 25.
The joint 22 of the ink container 20 is formed of modified polyphenyl ether (m-PPE). The inner diameter D2 of the joint 22 is 1.85 mm. An approach 23 having a slightly enlarged inner diameter is formed at the distal end of the joint 22 (see FIG. 2A). The length L2 of this approach 23 portion is 0.6 mm.
[0024]
(2-2) Ballpoint pen tip 30
The ballpoint pen tip 30 is formed by cutting a cylindrical material made of stainless steel, and has an outer diameter as shown in FIG. 2A.
Specifically, the distal end side of the columnar material is cut into a conical shape to form the tapered portion 31. Then, a ball house (not shown) is formed by cutting the inside on the tip side. On the other hand, the outer diameter of the rear end side of the columnar material is reduced by cutting to form the press-fit portion 32. The outer diameter D1 of the press-fit portion 32 is 1.9 mm.
[0025]
The arithmetic average roughness (Ra) of the outer periphery of the press-fitting portion 32 is measured using a non-contact three-dimensional measuring device (Mitaka Optical, NH-3) at a measuring pitch of 5 μm, a measuring distance of 2 mm, and a cutoff value of 0.8 mm. It was measured under the conditions. According to this, Ra was 0.83 μm.
The rear end of the press-fitting portion 32 is chamfered for convenience of insertion at the time of press-fitting. The length of the portion of the press-fitting portion 32 excluding the chamfered portion, that is, the length L1 of the portion holding the outer diameter D1 is 3.25 mm.
[0026]
Hereinafter, a back hole (not shown) is formed from the rear end side of the columnar material to the middle part. Then, an ink hole (not shown) connecting the ball house and the back hole is formed from the tip end side, and several grooves (not shown) (not shown) penetrate radially around the ink hole.
After the cemented carbide ball 34 is inserted into the ball house, the tip of the tapered portion 31 is crimped inward to form the caulked portion 33.
[0027]
The overall length of the ballpoint pen tip 30 thus formed is 12.3 mm.
(2-3) Manufacturing Process of Refill 11 The manufacturing process of the refill 11 is as follows.
First, the tip of the ink containing section 21 is filled with the ink 25, and further filled with the ink follower 26. On the other hand, the press-fitting portion 32 of the ballpoint pen tip 30 is press-fitted into the tip of the joint 22 (see FIG. 2B). Then, the rear end portion of the joint 22 into which the ball-point pen tip 30 is press-fitted is press-fitted into the front end of the ink container 21.
[0028]
Here, assuming that the length of the portion of the press-fitting portion 32 of the ball-point pen tip 30 where the outer diameter holds D1 is L1, and the length of the approach 23 of the joint 22 of the ink containing tube 20 is L2. In the process of press-fitting, the length (press-fitting length) L of the portion that deformed the inner wall of the ink storage tube 20 is:
L = L1-L2 = 3.25-0.6 = 2.65
Becomes 2.65 mm (see FIG. 2C).
[0029]
After the ball-point pen tip 30 is press-fitted, the temperature of the junction between the ball-point pen tip 30 and the joint 22 of the ink storage tube 20 is increased to 200 ° C. by induction heating, and the melted adhesion is achieved. Then, centrifugal processing is performed so that centrifugal force is applied in the direction of the tip of the ballpoint pen tip 30 to remove bubbles remaining in the refill 11.
(3) Third Embodiment In the ball-point pen according to the third embodiment, the inside of the ink container 20 communicates with the outside. In the present embodiment, as shown in FIG. 5, the ink containing pipe 20 has an ink containing section 21 for directly containing the ink 25 in the second half thereof and a press-fitting collector 27 in the first half thereof. And a joint 22 attached to the tip of the. Further, a ball-point pen tip 30 is attached to the tip of the joint 22 of the ink storage tube 20. The collector 27 has a structure for buffering a pressure difference between the inside of the ink storage tube 20 and the outside, and is formed of ABS resin. A guide core 28 for guiding the ink 25 to the ballpoint pen tip 30 by capillary force is provided at the axis of the collector 27. The guide core 28 is formed by a fiber bundle.
[0030]
(3-1) Ink storage tube 20
In the ink storage tube 20, the ink storage section 21 is configured as a shaft cylinder having a blind end made of polypropylene. The ink container 21 is filled with a low-viscosity aqueous ink as the ink 25.
The joint 22 of the ink container 20 is formed of polyacetal (POM). The inner diameter D2 of the joint 22 is 2.25 mm. An approach 23 having a slightly enlarged inner diameter is formed at the distal end of the joint 22 (see FIG. 6A). The length L2 of this approach 23 portion is 0.1 mm.
[0031]
(3-2) Ballpoint pen tip 30
The ballpoint pen tip 30 is formed by cutting a stainless steel cylindrical material, and has an outer diameter as shown in FIG. 6A.
Specifically, the distal end side of the columnar material is cut into a conical shape to form the tapered portion 31. Then, a ball house (not shown) is formed by cutting the inside on the tip side. On the other hand, the outer diameter of the column material is 2.3 mm. Therefore, the outer diameter D1 of the press-fitting portion 32 that is press-fitted into the ink storage tube 20 is 2.3 mm.
[0032]
The arithmetic average roughness (Ra) of the outer periphery of the press-fitting portion 32 is measured using a non-contact three-dimensional measuring device (Mitaka Optical, NH-3) at a measuring pitch of 5 μm, a measuring distance of 2 mm, and a cutoff value of 0.8 mm. It was measured under the conditions. According to this, Ra was 0.52 μm.
The rear end of the press-fitting portion 32 is chamfered for convenience of insertion at the time of press-fitting. The length of the portion of the press-fit portion 32 excluding the chamfered portion, that is, the length L1 of the portion having the outer diameter D1 is 2.8 mm.
[0033]
Hereinafter, a back hole (not shown) is formed from the rear end side of the columnar material to the middle part. Then, an ink hole (not shown) connecting the ball house and the back hole is formed from the tip end side, and several grooves (not shown) (not shown) penetrate radially around the ink hole.
After the cemented carbide ball 34 is inserted into the ball house, the tip of the tapered portion 31 is crimped inward to form the caulked portion 33.
[0034]
The overall length of the ballpoint pen tip 30 thus formed is 8.2 mm.
(3-3) Manufacturing Process of Ink Storage Tube 20 The manufacturing process of the ink storage tube 20 is as follows.
First, the ink 25 is filled with the open end of the barrel facing upward. On the other hand, the press-fitting portion 32 of the ballpoint pen tip 30 is press-fitted into the tip of the joint 22 (see FIG. 6B). Then, the joint 22 is inserted into the collector 27 into which the guide core 28 has been inserted in advance. Further, while inserting the collector 27 into the barrel filled with the ink 25, the rear end of the joint 22 is pressed into the open end of the barrel.
[0035]
Here, assuming that the length of the portion of the press-fitting portion 32 of the ball-point pen tip 30 where the outer diameter holds D1 is L1, and the length of the approach 23 of the joint 22 of the ink containing tube 20 is L2. In the process of press-fitting, the length (press-fitting length) L of the portion that deformed the inner wall of the ink storage tube 20 is:
L = L1-L2 = 2.8-0.1 = 2.7
Is 2.7 mm (see FIG. 6C).
[0036]
After the ball-point pen tip 30 is press-fitted, the temperature of the junction between the ball-point pen tip 30 and the joint 22 of the ink storage tube 20 is increased to 200 ° C. by induction heating, and the melted adhesion is achieved.
(4) Others In the first embodiment, the joint 22 is provided separately as in the refill 11 shown in FIG. However, as in the case of the refill 11 shown in FIG. 7, the ball-point pen tip 30 may be directly press-fitted without providing the joint 22 at the tip of the ink storage tube 20. The manufacturing process of such a refill 11 is as follows.
[0037]
First, the press-fitting portion 32 of the ballpoint pen tip 30 is press-fitted into the tip of the ink container 21 filled with the ink 25. Note that Ra of the outer periphery of the press-fit portion 32 is as described in the first embodiment.
After the ball-point pen tip 30 is press-fitted, the temperature of the junction between the ball-point pen tip 30 and the joint 22 of the ink storage tube 20 is increased to 200 ° C. by induction heating, and the melted adhesion is achieved. Then, centrifugal force is applied in the direction of the tip of the ballpoint pen tip 30 to remove the air bubbles remaining in the ink storage tube 20.
[0038]
Thereafter, the refill 11 is moved into a pressurized atmosphere of 3 atm (absolute pressure) filled with nitrogen gas, and then a tail plug 24 is pressed into the rear end, and this is melted and fixed. As a result, the pressurized nitrogen gas is sealed inside the ink container 20 behind the ink 25.
[0039]
【The invention's effect】
Since the present invention is configured as described above, it has the following effects.
That is, according to the description of the present invention, in a ball-point pen in which a part of a metal ball-point pen tip is press-fitted and mounted at the tip of a resin ink storage tube and the joint thereof is heated or melted and softened and adhered, By appropriately setting the surface roughness of the portion, it is possible to ensure that the joining portion is in close contact. In particular, in a pressurized ballpoint pen, by ensuring that the joints are brought into close contact with each other in this manner, it becomes possible to increase the durability against the pressure of the sealed gas and to secure airtightness.
[Brief description of the drawings]
FIG. 1 shows a shape of a refill according to a first embodiment of the present invention. Note that the ink storage tube is shown in cross section.
FIG. 2 illustrates a joint portion between a ballpoint pen tip and an ink container according to the first embodiment and the second embodiment of the present invention.
FIG. 3 shows the appearance of a ballpoint pen according to the first embodiment of the present invention. The cap is shown in a partial cross section.
FIG. 4 shows the shape of a refill according to a second embodiment of the present invention. Note that the ink storage tube is shown in cross section.
FIG. 5 is a partial cross-sectional view illustrating the shape of an ink container according to a third embodiment of the present invention.
FIG. 6 shows a joint portion between a ballpoint pen tip and an ink storage tube according to a third embodiment of the present invention.
FIG. 7 shows the shape of a refill according to another embodiment of the present invention. Note that the ink storage tube is shown in cross section.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Ball-point pen 11 Refill 12 Front shaft 13 Rear shaft 14 Cap 20 Ink storage tube 21 Ink storage part 22 Fitting 23 Approach 24 Tail plug 25 Ink 26 Ink follower 27 Collector 28 Guide core 30 Ball-point pen tip 31 Tapered part 32 Press-fit part 33 Press-fit part 34 ball

Claims (3)

A resin ink storage tube for storing ink inside,
A ball-point pen having a metal ball-point pen tip mounted on the front end side of the ink storage tube, a part of the rear end side being press-fitted,
By raising the temperature of the joint between the ball-point pen tip and the ink containing tube, the ball-point tip and the ink containing tube are melted or softened and adhered,
A ball-point pen characterized in that the arithmetic mean roughness of the surface of the portion at the rear end of the ball-point tip which is press-fitted is 0.5 μm or more and 3.0 μm or less. A resin ink storage tube for storing ink inside,
A ball-point pen having a metal ball-point pen tip mounted on the front end side of the ink storage tube, a part of the rear end side being press-fitted,
By raising the temperature of the joint between the ball-point pen tip and the ink containing tube, the ball-point tip and the ink containing tube are melted or softened and adhered,
A ball-point pen characterized in that the arithmetic mean roughness of the surface of the portion at the rear end of the ball-point pen which is press-fitted is 0.5 μm or more and 1.5 μm or less. The ballpoint pen according to claim 1, wherein a pressurized gas is sealed in a rear end side of the ink storage tube.

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