JP2021014097A - Ball-point pen tip and ball-point pen manufacturing method and spindle - Google Patents

Abstract

To provide a manufacturing method for forming an undercut groove portion in a series of manufacturing steps of a ball-point pen tip.SOLUTION: A manufacturing method of a ball-point pen tip 10 comprises: attaching a columnar workpiece W to a processor; forming, at one end of the workpiece W, a taper portion 15 corresponding to a pointed end portion of the ball-point pen tip 10; forming an annular and undercut groove portion 16 in the taper portion 15; and taking the ball-point pen tip 10 out of the processor.SELECTED DRAWING: Figure 3

Description

The present invention relates to a ballpoint pen tip, a method for manufacturing a ballpoint pen, and a spindle.

The ballpoint pen tip is a process of manufacturing a ball holder by stepwise cutting a columnar workpiece attached to a processing machine, and a ball is set on the manufactured ball holder and the tip of the ball holder is set. Manufactured by going through a caulking process. Generally, these series of steps are performed using one processing machine.

By the way, there is known a ballpoint pen tip in which an annular groove portion is formed at the tip end portion of the ballpoint pen tip formed in a tapered shape, and the groove portion is colored in the same color as the ink color (Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-34874

Patent Document 1 does not specifically disclose how the groove of the ballpoint pen tip is processed. In a general processing machine as described above, a spindle attached to the tip of a cutting tool is moved along the axial direction of a cylindrical workpiece to perform cutting, and therefore the undercut described in Patent Document 1 is performed. It is difficult to provide a shaped groove. If the groove is cut in a post-process after the ballpoint pen tip is manufactured, there is a risk that chips may be mixed in the gaps around the ball.

An object of the present invention is to provide a manufacturing method for forming an undercut-shaped groove in a series of manufacturing steps of a ballpoint pen tip.

According to one aspect of the present invention, in the method for manufacturing a ballpoint pen tip, a step of attaching a columnar work to a processing machine, a step of forming a tapered portion corresponding to the tip of the ballpoint pen tip at one end of the work, and the above-mentioned Provided is a method for manufacturing a ballpoint pen tip, which comprises a step of forming an annular and undercut-shaped groove portion in the tapered portion and a step of taking out the ballpoint pen tip from the processing machine. Further, in the method for manufacturing a ballpoint pen tip, a step of attaching a cylindrical work to a processing machine, a step of forming a tapered portion corresponding to the tip of the ballpoint pen tip at one end of the work, and an annular and undercut on the tapered portion. The processing machine includes a spindle and a cutting tool attached to the tip of the spindle, and the cutting tool includes the spindle and a step of taking out a ballpoint pen tip from the processing machine. A method for manufacturing a ballpoint pen tip, characterized in that the groove portion is formed by moving the ballpoint pen tip in a direction orthogonal to the rotation axis of the ballpoint pen, may be provided.

The groove may be formed by cutting from the outside to the inside in the radial direction with respect to the work. The processing machine may have a spindle and a cutting tool attached to the tip of the spindle, and the cutting tool may be moved in a direction orthogonal to the rotation axis of the spindle to form the groove. The cutting edge of the cutting tool may be arranged so as to have the same inclination as the inclination of the tapered portion. The groove may be further colored with the same color as the ink contained in the refill to which the ballpoint pen tip is attached.

Further, according to another aspect of the present invention, there is provided a method for manufacturing a ballpoint pen having a refill provided with the above-mentioned ballpoint pen tip. Further, according to another aspect of the present invention, a spindle for a ballpoint pen tip processing machine that forms an annular and undercut-shaped groove in the tapered portion of the ballpoint pen tip, and a cutting tool attached to the tip of the spindle is used. Provided is a spindle for a processing machine of a ballpoint pen tip, which is characterized in that the cutting tool is configured to be movable in a direction orthogonal to the rotation axis of the spindle.

According to the aspect of the present invention, in a series of manufacturing steps of a ballpoint pen tip, a common effect of providing a manufacturing method for forming an undercut-shaped groove portion is obtained.

FIG. 1 is a perspective view of a refill provided with a ballpoint pen tip manufactured by the manufacturing method according to the embodiment of the present invention. FIG. 2 is a partial vertical sectional view of the ballpoint pen tip of FIG. FIG. 3 is a diagram illustrating a part of a ballpoint pen tip manufacturing process. FIG. 4 is a partial vertical sectional view of a spindle for a ballpoint pen tip processing machine. FIG. 5 is a diagram illustrating a cutting process of a groove portion of a ballpoint pen tip. FIG. 6 is a vertical cross-sectional view of the compound writing instrument having the refill of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. A common reference code is attached to the corresponding components throughout the drawings.

FIG. 1 is a perspective view of a refill 1 provided with a ballpoint pen tip 10 manufactured by the manufacturing method according to the embodiment of the present invention. In the present specification, the ballpoint pen tip 10 side is defined as the "front" side and the side opposite to the ballpoint pen tip 10 is defined as the "rear" side in the axial direction of the refill 1 or the writing instrument described later. Similarly, in the ballpoint pen tip 10, the ball 11 side is defined as the "front" side, and the side opposite to the ball 11 is defined as the "rear" side.

The refill 1 has an ink storage tube 2 that stores ink. The outer surface of the rear end of the joint 3 is fitted to the inner surface of the front end of the ink storage tube 2. The outer surface of the rear end of the ballpoint pen tip 10 is fitted to the inner surface of the front end of the joint 3. Therefore, the ballpoint pen tip 10 is connected to the ink storage tube 2 via the joint 3. The outer surface of the front end of the tail plug 4 is fitted to the inner surface of the rear end of the ink storage tube 2.

FIG. 2 is a partial vertical sectional view of the ballpoint pen tip 10 of FIG. The ballpoint pen tip 10 has a ball 11 as a writing member and a ball holder 12 that rotatably holds the ball 11. The ball holder 12 has a large diameter portion 13 formed to have a larger diameter, a small diameter portion 14 formed to have a smaller diameter at the rear portion of the large diameter portion 13 and fitted with the front end portion of the joint 3, and the large diameter portion 13. It has a tapered portion 15 formed in a tapered shape at the front portion. An annular or band-shaped and undercut-shaped groove portion 16 is formed on the outer peripheral surface of the tapered portion 15. The ballpoint pen tip 10 is formed with an ink flow hole 17 penetrating in the axial direction. At the end of the ink flow hole 17, the ball 11 is rotatably held without the ball 11 coming off by crimping the tip of the tapered portion 15.

FIG. 3 is a diagram illustrating a part of the manufacturing process of the ballpoint pen tip 10. The ballpoint pen tip 10 has a step of manufacturing a ball holder 12 by stepwise cutting a columnar blank or a work W attached to a processing machine, and a ball 11 is set on the manufactured ball holder 12. , Manufactured through a step of crimping the tip of the ball holder 12. Generally, these steps are performed by one processing machine. In the present embodiment, the MULTISTAR LX-24 manufactured by MIKRON is used as the processing machine for manufacturing the ballpoint pen tip 10, but the present invention is not limited to this.

In FIG. 3A, the rear portion of the work W attached to the processing machine, that is, the rear portion of the large diameter portion 13 is machined to form the small diameter portion 14. In FIG. 3B, the front portion of the work W, that is, the front portion of the large diameter portion 13 is machined to form the tapered portion 15. In FIG. 3C, the outer peripheral surface of the tapered portion 15 is machined to form an annular or strip-shaped and undercut-shaped groove portion 16. In FIG. 3D, the ball 11 is attached to the manufactured ball holder 12, and then the completed ballpoint pen tip 10 is taken out from the processing machine. As a matter of course, the manufacturing process of the ballpoint pen tip 10 includes a plurality of steps such as forming the ink flow hole 17 in addition to the steps described with reference to FIG.

FIG. 4 is a partial vertical sectional view of a spindle 100 for a ballpoint pen tip processing machine. The spindle 100 is used to form the groove 16 shown in FIG. 3 (C) with respect to the tapered portion 15 shown in FIG. 3 (B). The spindle 100 includes a cylindrical outer housing 101, a hollow inner housing 102a and an inner housing 102b arranged on the inner circumference of the outer housing, a cam shaft 103 arranged in the inner housing 102a and the inner housing 102b, and a diamond. It has a cam lever 104 formed in a shape, a tool fitting 105, and a cutting tool 106 attached to the tool fitting 105. A cutting edge 107 is provided at the tip of the cutting tool 106. In the axial direction of the spindle 100, the cutting tool 106 side is defined as the "front" side, and the side opposite to the cutting tool 106 is defined as the "rear" side.

The camshaft 103 is movable in the front-rear direction with respect to the inner housing 102a and the inner housing 102b, and is urged rearward by a spring (not shown). An inclined cam surface 108 is provided on the side surface of the cam shaft 103. The cam lever 104 is provided so as to be swingable around the fulcrum 109. A cylindrical cam receiving surface 110 is provided at the rear end of the cam lever 104. A connecting portion 111 is provided at the front end portion of the cam lever 104. The tool fixture 105 is reciprocally attached to the front end surfaces of the inner housing 102a and the inner housing 102b along the radial direction of the outer housing 101. Therefore, the cutting tool 106 is configured to be movable in a direction orthogonal to the rotation axis of the spindle 100.

When the camshaft 103 moves forward, the cam surface 108 of the camshaft 103 and the cam receiving surface 110 of the cam lever 104 cooperate with each other to swing the cam lever 104 around the fulcrum 109. Specifically, in FIG. 4, the cam lever 104 swings counterclockwise. The connecting portion 111, which is the other end of the cam lever 104, is inserted into the engaging hole 112 provided in the tool fitting 105. Therefore, when the connecting portion 111 of the cam lever 104 swings, the tool fitting 105 receives the pressing force and moves in the radial direction due to the engagement between the connecting portion 111 and the engaging hole 112. Specifically, in FIG. 4, the tool fixture 105 moves to the right. By this movement, cutting with the cutting edge 107 is performed as described later. The tool fixture 105 is urged by the spring 113 in the direction of returning to the original position, that is, in the left direction in FIG.

When the camshaft 103 moves rearward, the pressing force by the cam lever 104 is released, so that the tool fitting 105 returns to its original position due to the urging force of the spring 113. At this time, due to the engagement between the engaging hole 112 of the tool fitting 105 and the connecting portion 111 of the cam lever 104, the cam receiving surface 110 of the cam lever 104 comes into contact with the cam surface 108 of the cam shaft 103, and the cam lever 104 is shown in FIG. At 4, it swings clockwise.

The inner housing 102a, the inner housing 102b, the camshaft 103, the cam lever 104, the tool fitting 105, the cutting tool 106, and the spring 113 are integrally integrated with the outer housing 101 of the spindle 100 by the processing machine. Rotate. This rotation is supported by bearings 114. As described above, the camshaft 103 moves back and forth while these members rotate, whereby the tool fixture 105 reciprocates.

FIG. 5 is a diagram illustrating a cutting process of the groove portion 16 of the ballpoint pen tip 10. In FIG. 5, the lower part in the figure is the vertical lower part, and the upper part in the figure is the vertical upper part. As shown in FIG. 5, a work W having a tapered portion 15 is attached to a processing table S of a processing machine.

FIG. 5A shows a state in which the spindle 100 is lowered by the processing machine. FIG. 5B shows a state in which the lowering of the spindle 100 is completed and the cutting tool 106 is moved in a direction orthogonal to the rotation axis of the spindle 100. That is, the camshaft 103 moves forward by the processing machine, and the tool fixture 105 moves in the radial direction via the cam lever 104. FIG. 5C shows a state in which the cutting edge 107 of the cutting tool 106 is in contact with the tapered portion 15 of the work W and cutting is being performed. That is, when the cutting tool 106 rotates around the work W, the cutting tool 106 is cut over the entire circumference of the tapered portion 15 of the work W, and an annular and undercut-shaped groove portion 16 is formed. Next, the camshaft 103 is moved rearward by the processing machine, and the step of forming the groove portion 16 is completed.

According to the spindle 100, after the spindle 100 is lowered, the cutting tool 106 can be moved in a direction orthogonal to the rotation axis of the spindle 100, so that it is not possible to perform machining simply by lowering the spindle 100. , The annular and undercut-shaped groove portion 16 can be machined.

The method for manufacturing the ballpoint pen tip 10 according to the present embodiment is, in short, a step of attaching a columnar work W to the processing machine, and a step of forming a tapered portion 15 corresponding to the tip of the ballpoint pen tip 10 at one end of the work W. It includes a step of forming an annular and undercut-shaped groove portion 16 in the tapered portion 15 and a step of taking out the ballpoint pen tip 10 from the processing machine after all the steps are completed. That is, the cutting process of the undercut-shaped groove portion 16 can be performed not in a separate step but in a series of manufacturing steps for manufacturing the ballpoint pen tip 10. Therefore, it is possible to prevent chips from being mixed into the gaps around the ball 11 by cutting the groove 16 in a post-process after the ballpoint pen tip 10 is manufactured.

The groove portion 16 may be cut with respect to the tapered portion 15 at any time as long as the tapered portion 15 is already formed. For example, in FIG. 3, the groove portion 16 is formed before the ball 11 is attached, but in FIG. 5, the groove portion 16 is formed after the ball 11 is attached.

As described above with reference to FIG. 5, the groove portion 16 is formed by cutting from the outside to the inside in the radial direction with respect to the work W. That is, the processing machine has a spindle 100 and a cutting tool 106 attached to the tip of the spindle 100, and the cutting tool 106 is moved in a direction orthogonal to the rotation axis of the spindle 100 to form the groove portion 16. When cutting the groove portion 16, as shown in FIG. 5, the cutting edge 107 of the cutting tool 106 is arranged so as to have the same inclination as the inclination of the tapered portion 15. By changing the shape of the cutting edge 107, the shape of the groove portion 16 can be arbitrarily formed.

FIG. 6 is a vertical cross-sectional view of the compound writing tool 50 having the refill of FIG. The compound writing tool 50 covers the axle cylinder 51, a plurality of refills 1 housed in the axle cylinder 51, the knock rod 52, the erasing member 53 provided at the rear end of the knock rod 52, and the erasing member 53. It has a knock cover 54 to be used. The compound writing tool 50 can selectively put one of the plurality of refills 1 into the writing state by knocking the rear end portion.

Each of the refills 1 of the compound writing tool 50 contains inks of different colors. In particular, when the barrel 51 is opaque, or when the ink storage tube 2 is opaque even if the barrel 51 is transparent, the color of the ink contained in the refill 1 is unknown until the writing is done and the handwriting is seen. It is inconvenient to have it. Therefore, the groove 16 of the refill 1 is colored with a paint having the same color as the ink contained in the refill 1 to which the ballpoint pen tip 10 is attached. Since the groove 16 of the ballpoint pen tip 10 protrudes from the front end of the barrel 51 in the writing state, the color of the ink contained in the refill 1 can be recognized by observing the color of the colored groove 16.

Further, by changing the density of the color colored in the groove 16 as well as the inks of different colors, it is possible to recognize different ink types such as oil-based ink, water-based ink, gel ink, and heat-discoloring ink. May be good.

In the case of the compound writing tool 50, since the refill 1 bends when the ballpoint pen tip 10 of the refill 1 selected by the knock operation protrudes from the shaft cylinder 51, the ballpoint pen tip 10 is at the edge of the opening at the front end of the shaft cylinder 51. Rub with. As a result, the paint in the groove 16 may peel off. Therefore, it is preferable to use an ultraviolet curable paint as a paint for coloring the groove portion 16. As a result, the durability of the paint applied to the groove 16 against friction is improved, and peeling of the paint is prevented.

The ultraviolet curable coating material is composed of a solvent, a polymerization initiator, a viscosity modifier, a colorant, a coating component containing a main resin, an additive, etc., and in particular, the number of (meth) acrylic groups in one molecule as the main resin is 1 to 7. Contains 20 to 90% by mass of a reactive oligomer composed of a mixture of acrylic acrylate and polyester acrylate having (meth) acryloyl groups in one molecule of 1 to 5 with respect to the coating material components (excluding solvent). By doing so, it is possible to color the ball pen tip 10 with excellent adhesion to the groove 16 and hardness.

Examples of the acrylic acrylate include compounds having a structure in which one or more (meth) acryloyl groups are introduced into one molecule of oligomer. Here, the (meth) acryloyl group refers to an acryloyl group or a methacryloyl group (hereinafter, the same applies). The number of (meth) acryloyl groups in one molecule of the oligomer is preferably 2-4. The mass average molecular weight is preferably 5,000 to 100,000. If the molecular weight is too low, basic coating film physical characteristics cannot be obtained. In addition, the cross-linking reaction due to ultraviolet irradiation is less likely to proceed, so that the coating film tends to remain sticky. Further, it is considered that it volatilizes in the same manner as the solvent when it dries, which deteriorates the curability and the uniformity of the coating film. On the other hand, if the molecular weight is too high, the appearance (smoothness) is deteriorated, and the thinner dilution ratio at the time of coating needs to be increased due to the increase in viscosity due to the polymerization, which lowers the coating adhesion efficiency.

Examples of the polyester acrylate include compounds having a structure in which one or more (meth) acryloyl groups are introduced into one molecule of polyester. The number of (meth) acryloyl groups in one molecule of the oligomer is preferably 1-5. The mass average molecular weight is preferably 3,000 to 100,000. If the molecular weight is too low, basic coating film physical characteristics cannot be obtained. In addition, the cross-linking reaction due to ultraviolet irradiation is less likely to proceed, so that the coating film tends to remain sticky. Further, it is considered that it volatilizes in the same manner as the solvent when it dries, which deteriorates the curability and the uniformity of the coating film. On the other hand, if the molecular weight is too high, the appearance (smoothness) is deteriorated, and the thinner dilution ratio at the time of coating needs to be increased due to the increase in viscosity due to the polymerization, which lowers the coating adhesion efficiency.

Since the mixture of the acrylic acrylate and the polyester acrylate can be suitably used as the main resin in the UV paint for metals of the present invention, the content thereof is the coating film excluding the solvent which is a volatile component of the UV paint for metals. It requires 10% by mass or more with respect to the constituent components, preferably 20 to 90% by mass, and more preferably 40 to 80% by mass. If the content is too small, the adhesiveness with the metal material is lowered, and if the content is too large, it becomes difficult to adjust the physical characteristics (hardness, etc.) of the coating film other than the adhesiveness.

The step of coloring the groove 16 with the same color as the ink contained in the refill 1 to which the ballpoint pen tip 10 is attached is performed after the step of taking out the ballpoint pen tip 10 from the processing machine. However, coloring may be performed in one step in the processing machine.

In addition to the paint or instead of the paint, the groove 16 may be coated with a water repellent that repels the ink ejected from the refill 1. As a result, it is possible to prevent the ink ejected from the refill 1 but not transferred to the writing surface from adhering to the tapered portion 15. That is, when such ink adheres to the tapered portion 15 and accumulates in a certain amount, it suddenly shifts to the writing surface and causes the writing surface to be soiled. By applying the water repellent agent to the groove portion 16, it is possible to prevent the ink from adhering to the tapered portion 15. It should be noted that, instead of the compound writing tool, as a single writing tool, only one refill 1 having the ballpoint pen tip 10 having the groove 16 formed therein may be accommodated in the shaft cylinder.

The groove 16 may be colored to determine the properties of the ink, regardless of the color of the ink contained in the refill 1. For example, among a plurality of refills 1, the groove 16 of the ballpoint pen tip 10 of the refill 1 containing the heat-discoloring ink is colored black, and the groove 16 of the ballpoint pen tip 10 of the refill 1 containing the non-heat-discoloring ink is colored black. May be colored in white.

Here, the thermochromic ink maintains a predetermined color (first color) at room temperature (for example, 25 ° C.), and when the temperature is raised to a predetermined temperature (for example, 60 ° C.), it changes to another color (second color). Ink that has the property of returning to the original color (first color) when cooled to a predetermined temperature (for example, −5 ° C.). In a writing instrument using a heat-changing ink, the second color is made colorless, and the temperature of the drawn line drawn with the first color (for example, red) is raised to make it colorless, which is referred to as "erasing" here. Therefore, the erasing member 53 made of a highly wearable material as a friction body rubs against the writing surface or the like on which the drawn lines are written to generate frictional heat, thereby changing the drawn lines to colorless, that is, erasing them. As a matter of course, the second color may be a color other than colorless.

Further, the heat-discoloring ink is a heat-discoloring composition containing at least a leuco pigment, a color developer, and a suitable discoloration temperature adjusting agent, and is microencapsulated so that the average particle size is 0.2 to 3 μm. Therefore, the authenticity of the ink can be easily determined by including the heat-discoloring microcapsule pigment having a low-temperature side discoloration temperature of -30 ° C or higher and the heat-discoloring microcapsule pigment having a low-temperature side discoloration temperature of less than -30 ° C. It is possible to provide a thermochromic writing tool that is possible. The "average particle size" is a value of D50 calculated on a volume basis with a refractive index of 1.81 using a particle size analyzer [Microtrack HRA9320-X100 (manufactured by Nikkiso Co., Ltd.)].

1 Refill 2 Ink storage tube 3 Fitting 4 Tail plug 10 Ballpoint pen tip 11 Ball 12 Ball holder 13 Large diameter part 14 Small diameter part 15 Tapered part 16 Groove part 17 Ink flow hole 50 Double writing tool 51 Shaft cylinder 52 Knock rod 53 Erase member 54 Knock cover 100 Spindle 101 Outer housing 102a, 102b Inner housing 103 Camshaft 104 Cam lever 105 Tool fixture 106 Cutting tool 107 Cutting edge 108 Cam surface 109 fulcrum 110 surface 111 Connecting part 112 Engagement hole 113 Spring 114 Bearing

Claims (7)

In the method of manufacturing ballpoint pen tips
The process of attaching a columnar workpiece to the processing machine and
A step of forming a tapered portion corresponding to the tip of a ballpoint pen tip at one end of the work, and
A step of forming an annular and undercut-shaped groove in the tapered portion, and
A method for manufacturing a ballpoint pen tip, which comprises a step of taking out the ballpoint pen tip from the processing machine. The method for manufacturing a ballpoint pen tip according to claim 1, wherein the groove is formed by cutting from the outside to the inside in the radial direction with respect to the work. The second aspect of the present invention, wherein the processing machine has a spindle and a cutting tool attached to the tip of the spindle, and the cutting tool is moved in a direction orthogonal to the rotation axis of the spindle to form the groove. The method for manufacturing a ballpoint pen tip described. The method for manufacturing a ballpoint pen tip according to claim 3, wherein the cutting edge of the cutting tool is arranged so as to have the same inclination as the inclination of the tapered portion. The method for manufacturing a ballpoint pen tip according to any one of claims 1 to 4, further comprising a step of coloring the groove portion with the same color as the ink contained in the refill to which the ballpoint pen tip is attached. A method for manufacturing a ballpoint pen having a refill provided with the ballpoint pen tip according to any one of claims 1 to 5. A spindle for a ballpoint pen tip processing machine that forms an annular and undercut groove in the tapered portion of the ballpoint pen tip.
A spindle for a ballpoint pen tip processing machine, which has a cutting tool attached to the tip of the spindle and is configured to be movable in a direction orthogonal to the rotation axis of the spindle. ..

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