JP2003276383A - Ball-point pen tip and method for manufacture thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball-point pen tip which prevents the feel of catch occurring during writing with the ball-point pen, especially a feel of catch which is apt to occur when the ball diameter is small. <P>SOLUTION: A contour line, in the longitudinal section, of a point where the outside of a housing of the ball-point pen tip comes into contact with a plane for writing when the ball-point pen is tilted, is curved or straight-line or polygonal at more than 150°. In addition, the contour line, in the longitudinal section, of the housing on the tip side beyond said contact point, is curved or straight-line or polygonal at more than 150°. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen tip using a ball as a writing medium and a method for manufacturing the ballpoint pen tip.

[0002]

2. Description of the Related Art Conventionally, a ballpoint pen 50 as shown in FIG. 8 is known. The ballpoint pen 50 has a ballpoint pen tip 100 at its tip, and the ballpoint pen tip 100 has a housing 105 and a ball 12. In addition, at the time of writing, the ink attached to the ball 12 is attached to the surface to be written and written. FIG. 10 is an enlarged view of the tip portion of the ballpoint pen tip in the ballpoint pen of FIG. A ball holding portion 11 for rotatably holding a ball 12 is provided on the tip side of the housing 105 of the ball-point pen tip 100.
The rear end side has a rear hole 16 serving as an ink flow passage, and the ink guide hole 14 for communicating ink from the rear hole 16 to the ball holding portion 11 to guide the ink to the vicinity of the ball 12 is provided. There is. Further, there is a gap 20 between the ball 12 and the tip of the housing 105.
2 rotates, and the ink adhering to the ball 12 is appropriately discharged in a substantially constant amount.

Next, a conventional method of manufacturing the ball-point pen tip 100 will be described. First, a metal round bar having a predetermined length is cut into a predetermined length, a taper portion 13 is formed on the outer side so that the diameter becomes smaller toward the tip side, and a ball holding portion 11 and an ink guiding hole 14 are formed on the inner side. Further, the rear hole 16 and the like are formed to form the housing 105. The rear side of the ball holding portion 11 has a seat surface 17, and the seat surface 17 receives the force acting on the ball 12 by the writing pressure during writing. Also, the ink guide hole 1
The inner diameter of 4 is smaller than the ball diameter D. Then, with the tip of the ball 12 protruding by the length H, the housing 1
05, the housing 105
The tip side of the is crimped to form the crimped portion 102.

This caulking process is a process in which the opening width L at the tip of the housing 105 is made smaller than the diameter D of the ball 12 and the tip of the ballpoint pen tip is deformed toward the inside, while allowing the ball 12 to rotate. , Ball 12
It is performed to prevent the falling of the tip from the tip direction.

When using the ballpoint pen 50, the ballpoint pen 50 itself is often tilted as shown in FIG. Here, as shown in FIG. 9, when the ball-point pen 50 is gradually tilted, the ball-point pen tip 100 is eventually obtained.
The housing 105 contacts with the surface A of the paper (writing material) at any contact point 22 (FIG. 10). In order for the ballpoint pen 50 to be writable, at least the exposed portion of the ball 12 must be in contact with the paper surface. Therefore, the range of the inclination angle at which a line or the like can be drawn using the ballpoint pen 50 is It is the range from the state where the ballpoint pen 50 is perpendicular to the surface of the paper (the state where there is no inclination) to the point where the ballpoint pen tip 100 contacts the paper surface at the contact point 22. That is, if the ball-point pen 50 is tilted further, the ball 12 will leave the plane of the paper.

A person skilled in the art can gradually write the ballpoint pen 50 as shown in FIG.
Value α of the inclination angle (angle θ between the ballpoint pen and the paper)
Is called the minimum writable angle. Using the example above,
As shown in FIG. 10, when the contact point 22 of the housing 105 and the ball 12 come into contact with the paper surface A at the same time, the angle α between the axis line B of the ballpoint pen tip and the paper surface A is the minimum writable angle. Note that when writing with an inclination, the ball 12 moves laterally by the amount of the gap 20, so that the minimum writable angle actually decreases by about 1 to 2 °. However, since this influence is small, the minimum writable angle α in the present application will be described as the minimum writable angle that does not consider this influence.

Further, the conventional ballpoint pen tip 100
10, the contact point 22 is a polygonal line, and the angle S on the housing side at the contact portion is shown in FIG.

In view of the performance of the ball-point pen 50, it is desirable that the minimum writable angle α is as small as possible. The minimum writable angle α is generally the ball diameter D and the housing 105.
It is determined by the shape and the like, and is designed to reduce the minimum writable angle α.

For example, it is disclosed in Japanese Patent Application Laid-Open No. 11-348486, that the thickness of the rim at the tip of the ball-point pen tip is reduced so that the outer peripheral edge of the tip of the housing 105 is less likely to contact the writing material. By forming the caulked portion 102 of the ball-point pen tip into a convex curved surface toward the ball 12 as shown in FIG. 13A as in the technology, the thickness of the tip of the ball-point pen tip is maintained while maintaining the thickness of the bent portion. It has been proposed that the outer peripheral edge of the ball-point pen tip is less likely to come into contact with the writing material when writing is performed with a reduced thickness and with an inclination. According to the above-mentioned conventional technique, the minimum writable angle α is reduced, the outside of the housing 105 is less likely to come into contact with the material to be written, the feeling of being caught is less likely to occur, and the feeling of writing is improved.

[0010]

By the way, in recent years, a ball-point pen tip having an extremely small ball diameter and, conversely, a ball-point pen tip having an extremely large ball diameter have been proposed. In a ballpoint pen using these ballpoint pen tips, the writing operation is often performed by inclining it to an angle close to the minimum writable angle α. That is, in recent years, in order to make the writing line of the ballpoint pen 50 thin, a ballpoint pen 50 having a small ball diameter D has been put into practical use. Even if the ball diameter D is small, the thickness of the ball holding portion 11 and the caulking portion 102 of the housing 105 needs to be strong enough to withstand the writing pressure and needs to be a certain thickness or more.
Therefore, the thickness of the ball holding portion 11 and the caulking portion 102 becomes relatively thick with respect to the ball diameter D, and as a result,
The minimum writable angle α becomes large. Therefore, even if the ball-point pen is slightly tilted, it comes close to the minimum writable angle α, and the user is forced to tilt the ball-point pen at an angle close to the minimum writable angle α for writing.

Further, if the ball diameter D is small, the contact area with the surface of the paper which is the writing material becomes small, so that the stress of the writing portion increases even with the same writing pressure, and the deformation of the paper increases. In this case, as shown in FIG. 12, the paper is deformed into a shape like the surface A ′ of the paper, and the housing 105 comes into contact with the tip side of the contact point 22.

On the other hand, in many cases, even if the ball diameter D is large, the writing operation is performed by inclining it to an angle close to the minimum writable angle α. That is, when the ball diameter D is increased and the writing line is reduced, the housing 105
It is necessary to reduce the opening width L at the tip after caulking. However, when the opening width L is the same, as the ball diameter D increases, the height H of the portion of the ball 12 protruding from the housing 105 (ball ejection amount) decreases, and the minimum writable angle α decreases. It gets bigger.
Therefore, even if the ball-point pen is slightly tilted, it comes close to the minimum writable angle α, and the user is forced to tilt the ball-point pen at an angle close to the minimum writable angle α for writing.

Further, in the ball-point pen tip 120 which is another example of the prior art shown in FIG. 11, the minimum writable angle α is further large. In the ballpoint pen tip 120 shown in FIG. 11, a spring 27, which is an urging means for urging the ball 12 toward the protruding side, is provided behind the ball 12 in the housing 105 of the ballpoint pen tip 120, and the ball 12 moves in the axial direction. Yes, ball 1 when not writing
2 is biased to the protruding side. On the other hand, when the ball 12 is pressed by writing or the like and a force larger than that of the biasing means acts on the ball 12, the ball 12 moves to the seat surface 17 side.
Therefore, the height H ′ of the portion of the ball 12 protruding from the housing during writing becomes smaller than the height H of the portion of the ball protruding from the housing when not writing,
The minimum writable angle α becomes large.

By the way, as described above, writing is possible even if the ball-point pen is tilted at an angle close to the minimum writable angle α, and it is possible to write even if it is tilted at the minimum writable angle α. However, the conventional ballpoint pen has a very poor writing feeling when tilted at an angle close to the minimum writable angle α. That is, when the ballpoint pen 50 is used while being inclined at an angle close to the minimum writable angle α, the writing material such as paper comes into contact with the housing 105 of the ballpoint pen tip 100, and a feeling of being caught is generated. The feeling of being caught by the writing instrument in the prior art is a feeling of scraping the paper surface. That is, when the conventional ballpoint pen 50 is tilted at an angle close to the minimum writable angle α, discontinuous resistance is felt in the direction opposite to the writing direction.

Further, the ball-point pen tip manufactured by the conventional method is as shown in FIG. 13 (a) or FIG. 14 (a). As shown in FIG. 13B and FIG. 14B, the caulked portion 102 may have a portion (so-called burr) that is locally deformed more than the shape before processing. That is, the caulking process is performed by the ballpoint pen tip 1
Since the tip end portion of No. 00 is subjected to plastic deformation by applying stress from the outside to the inside, the burr has an acute angle shape as shown in FIGS. 13B and 14B. The tip of this burr becomes the contact point 22. Therefore, when writing with an inclination, the writing material and the burr come into contact with each other, and a strong feeling of being caught is felt.

The above-mentioned feeling of catching may be alleviated by long-term use, but when the material of the ball-point pen tip is stainless steel, the feeling of catching remains. Therefore, an object of the present invention is to suppress the feeling of being caught when writing with a ballpoint pen.

[0017]

As described above, the catching feeling may be reduced by long-term use, but when the ballpoint pen tip is made of stainless steel, the catching feeling remains. Therefore, a ballpoint pen attached with a ballpoint pen tip made of stainless steel and a ballpoint pen attached with a ballpoint pen tip made of a copper alloy material were simultaneously used for a long period of time, and the two were compared. As a result, the ball-point pen tip made of copper alloy has a portion (contact point 22) that comes into contact with the surface of the paper due to long-term use, and becomes rounded, whereas the ball-point pen tip made of stainless steel has a portion that comes into contact with the surface of the paper. It was found that the (contact point 22) maintains the shape at the time of processing and causes a feeling of being caught.

Therefore, the inventors of the present invention considered, when processing a ball-point pen tip made of a stainless material, previously processing the same shape as that after long-term use.

The invention of claim 1 thus completed is a ball-point pen tip having a ball and a stainless steel housing, and rotatably holding the ball in the housing, the ball-point pen tip being pressed against a flat surface. When tilted and the housing is in contact with the plane,
The ball-point pen tip is characterized in that a contour line of the contact portion in a vertical cross section of the housing is a curved line, a straight line, or a polygonal line of 150 ° or more.

Here, stainless steel includes ferrite type, austenite type, and martensite type, and is generally a material having excellent corrosion resistance and wear resistance.

According to the first aspect of the present invention, when the ball-point pen tip is tilted while the ball is pressed against the flat surface and the housing is brought into contact with the flat surface, the contour line of the contact portion in the longitudinal section of the housing is Since it has a curved shape, a linear shape, or a bent line shape of 150 ° or more, a feeling of being caught does not occur, and good writing comfort can be obtained. In addition, especially because it is a ballpoint pen tip made of stainless steel,
If there is a feeling of being caught at the beginning, the feeling of catching will continue because the material is less likely to wear, but according to the present invention, there is no feeling of getting caught from the beginning.

The invention according to claim 2 is the ball-point pen tip according to claim 1, wherein the ball has a diameter of 0.5 mm or less.

According to the second aspect of the invention, the ball diameter of the ball-point pen tip is 0.5 mm or less, and the thickness of the ball holding portion and the caulking portion becomes relatively thicker than the ball diameter D. The minimum writable angle α becomes large.
Therefore, when writing with an inclination, the ballpoint pen tip is more likely to come into contact with the writing material, which is particularly effective.

The invention according to claim 3 is characterized in that the height H of the portion of the ball protruding from the housing when not writing is less than 30% of the diameter D of the ball. This is a ballpoint pen tip.

Further, the invention according to claim 4 is a ball-point pen tip which has a ball and a housing, and rotatably holds the ball in the housing, wherein the diameter D of the ball is 0.8 mm or more, The height H of the portion of the ball protruding from the housing when not writing was less than 30% of the diameter D of the ball, and the ballpoint pen tip was tilted while the ball was pressed against the flat surface to bring the housing into contact with the flat surface. At this time, the contour line of the contact portion in the vertical cross section of the housing is a curved line, a straight line, or a polygonal line of 150 ° or more.

According to the third aspect of the invention, the height H of the portion of the ball protruding from the housing when not writing is H.
Is less than 30% of the diameter D of the ball, and the minimum writable angle α becomes large. According to the invention of claim 4, the diameter D of the ball is 0.8 mm or more, and the height H of the portion of the ball protruding from the housing when not writing is less than 30% of the diameter D of the ball. Therefore, the minimum writable angle α becomes large. Therefore, when a ballpoint pen using the ballpoint pen tip according to the invention of claim 3 or 4 is written while being inclined, the ballpoint pen tip is more likely to come into contact with the writing material, which is particularly effective.

According to a fifth aspect of the present invention, the contour line between the tip of the housing and the contact portion of the housing in the vertical cross section of the housing is a curved line, a straight line or 150 °.
The ball-point pen tip according to any one of claims 1 to 4, wherein the ball-point pen tip is a polygonal line composed of the above corners.

According to the fifth aspect of the present invention, even if the surface of the paper as the writing material is deformed by the writing pressure and enters the housing side from the virtual plane A, from the tip of the housing in the vertical cross section of the housing. Since the contour line of the housing reaching the contact portion is a curved line, a straight line, or a polygonal line composed of corners of 150 ° or more, even if the writing material comes into contact with the writing material, a feeling of being caught is not generated, which is excellent. Writing comfort is obtained.

According to a sixth aspect of the present invention, the angle between the axis of the ballpoint pen tip and the plane is 50 ° or less when the ballpoint pen tip is tilted while the ball is pressed against the plane and the housing is brought into contact with the plane. The ball-point pen tip according to any one of claims 1 to 5, wherein:

According to the sixth aspect of the present invention, the angle between the axis of the ballpoint pen tip and the plane is 50 ° when the ballpoint tip is tilted while the ball is pressed against the plane and the housing is brought into contact with the plane. Since it is below, the minimum writable angle α is 50 ° or less, and even if the ball-point pen tip is largely tilted, the housing is unlikely to contact the surface of the paper, and the writing feeling is particularly good.

The invention according to claim 7 is characterized in that biasing means for biasing the ball toward the projecting side is provided behind the ball inside the housing, and the ball is movable in the axial direction. Item 7. A ball-point pen tip according to any one of items 1 to 6.

In the invention according to claim 7, since the ball is movable in the axial direction, if the ball-point pen tip is tilted while the ball is pressed against a plane, the minimum writable angle α becomes large. Therefore, when writing with an inclination,
Since the ballpoint pen tip is more likely to come into contact with the writing material, it is particularly effective in improving the writing feeling.

According to an eighth aspect of the invention, the thickness W of the ball holding portion of the housing in a plane perpendicular to the axis of the ballpoint pen tip through the center of the ball is 20 μm to 50 μm with reference to the state where the ball is pressed against the plane. The ballpoint pen tip according to any one of claims 1 to 7, wherein:

According to the invention of claim 8, the thickness W of the ball holding portion of the housing in the plane perpendicular to the axis of the ball-point pen tip through the center of the ball is 20 μm to 50 μm with reference to the state where the ball is pressed against the plane. Because there is
The ball-point pen tip is not easily damaged during writing.

The invention described in claim 9 is the invention according to claims 1 to 8.
In the method for producing the ball-point pen tip according to any one of 1 to 3, the ball is inserted into the housing, the open end of the housing is closely contacted with the ball and caulked, the outer corner of the housing is removed, and then the ball is tipped. The ball-point pen tip manufacturing method is characterized in that the ball-point pen tip is pressed from the direction toward the housing.

According to a tenth aspect of the present invention, in a method of manufacturing a ball-point pen tip having a ball and a stainless steel housing, the ball being rotatably held in the housing, the ball is inserted into the housing, A method for manufacturing a ball-point pen tip, characterized in that after the open end of the housing is brought into close contact with the ball and caulked, the outer corner of the housing is removed, and then the ball is pressed from the tip direction toward the housing side.

By using the manufacturing method according to the ninth or tenth aspect of the present invention, it is possible to easily manufacture a ballpoint pen tip without a feeling of being caught. In other words, if the tip of the ballpoint pen tip is swaged and then the corner is cut off with a knife or a file, not only the corner but also the tip of the ballpoint pen tip will be deformed.
The gap between the ball and the ball-point pen tip is likely to be non-uniform, making it impossible to manufacture an accurate ball-point pen tip. According to the present invention, since the ball tip is intimately contacted with the ball inside and crimped, the ball and the ball-point tip remain in contact during the process of removing the corners, and the ball is moved in the tip direction later. By pressing from the bottom to plastically deform the rear end side of the ball holding portion of the ball-point pen tip, a uniform gap can be formed between the ball and the ball-point tip and the ball-point tip can be manufactured with high accuracy.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Specific embodiments of the present invention will be described below. FIG. 1 is a sectional view of a ball-point pen tip according to the first embodiment of the present invention. Figure 2
It is sectional drawing at the time of caulking of the ball-point pen tip in the 1st Embodiment of this invention. FIG. 3 is an enlarged cross-sectional view of a caulking portion at the time of caulking the ballpoint pen tip according to the first embodiment of the present invention. FIG. 4A is a sectional view of a ball-point pen tip according to the second embodiment of the present invention. FIG. 4B is an enlarged sectional view of the vicinity of the inclined writing contact portion of the ball-point pen tip according to the second embodiment of the present invention. FIG. 5: is sectional drawing of the ball-point pen tip in the 3rd Embodiment of this invention. FIG. 6 is a sectional view of a ball-point pen tip according to the fourth embodiment of the present invention. FIG. 7 is a cross-sectional view at the time of pressing with a pressing tool at the time of manufacturing the ball-point pen tip according to the first embodiment of the present invention.

The ball-point pen tip 1 according to the first embodiment of the present invention is shown in FIG. 1 and is attached to the tip of a ball-point pen like the ball-point pen tip 100 of the prior art. The ballpoint pen tip 1 includes a housing 5 and a ball 1.
When writing, the ink adhered to the ball 12 held in the housing 5 adheres to the writing surface and is written.

Then, on the front end side of the housing 5,
A ball holding portion 11 that holds the ball 12 rotatably is provided, and a rear hole 16 that serves as an ink flow path is provided at the rear end side. The ball 12 is communicated from the rear hole 16 to the ball holding portion 11. An ink guide hole 14 for guiding ink is provided in the vicinity. Further, there is a gap 20 between the ball 12 and the ballpoint pen tip 1 so that the ball 12 can be used for writing.
Is rotated and the ink adhering to the balls 12 is appropriately discharged in a substantially constant amount. The ball holding portion 11 has a seating surface 17 on the rear side, and the ball 12 is pressed by the writing pressure during writing.
The seat surface 17 receives a force acting on the seat surface 17.

The diameter of the ball 12 is 0.5 mm. The size relationship among the inner diameter of the ink guiding hole 14, the inner diameter of the rear hole 16, and the depth of the ball holding portion 11 is the same as that of the ballpoint pen tip 100 of the related art. Further, the caulking portion 30 of the ball-point pen tip 1 is caulked inward,
On the outside of the tip, the contour line in the vertical section is a curved surface. The opening width L of the opening at the tip of the housing 5 is 0.45.
mm to 0.49 mm, preferably 0.47 mm to
It is smaller than 0.5 mm, which is the diameter D of the 0.485 mm ball 12. Further, the height H of the ball 12 protruding from the housing 5 when not writing is 0.150 to 0.165.
mm, and the ratio (H / D) to the ball diameter is 30 to
33.3%.

The ball holding portion thickness W is the thickness of the housing 5 on a plane that passes through the center of the ball 12 and is perpendicular to the axis B of the ballpoint pen tip 1 with the ball pressed against the plane. The thickness W of the ball holding portion of the ballpoint pen tip 1 is about 40 μm, preferably 20 μm to 50 μm.

The manufacturing process of the ball-point pen tip 1 is the same as that of the conventional ball-point pen tip except for the crimping process. Caulking of the ballpoint pen tip 1 is shown in FIGS. Contact surface 4 of the caulking tool 40
1 is pressed against the tip of the housing 5 of the ballpoint pen tip. As shown in FIG. 3, the contact surface 41 of the caulking tool 40 has a protrusion 42 that is convex toward the axis of the ball-point pen tip 5, and the rear end side root 43 of the protrusion 42 is R-shaped. is there. If caulking is performed by the caulking tool 40, the tip of the ball-point pen tip is bent inward, and at the same time, the R-shaped shape of the rear end side root 43 is transferred,
The outside of the tip of the ballpoint pen tip is curved. That is, during crimping, the outer side of the tip end portion of the ballpoint pen tip is pressed by the rear end side base 43 and becomes a curved surface shape without being a corner. When the caulking process is performed by the caulking device 40, just like the conventional caulking process, the outside of the tip of the ballpoint pen tip becomes a curved surface, and the ballpoint pen chip is processed without increasing the number of processing steps. You can

Further, since the caulking process is performed while the ball 12 is in contact with the seat surface 17, there is no gap in which the ball 12 can move in the axial direction after the caulking process, and the ball 12 hardly moves in the axial direction. .

Next, the situation when the ball-point pen tip 1 tilts and comes into contact with the housing 5 will be described. When writing with a ballpoint pen, the ballpoint pen tip 1 tilts while the ball 12 is pressed backward. A virtual plane A in FIG. 1 is a surface that contacts both the ball 12 and the housing 5. As described above, the ball 12 hardly moves in the axial direction. Therefore, the position of the ball in FIG. 1 is the position of the ball in the pressed state, and the position of the ball 12 in the non-written state and the state of the written and pressed state is substantially the same.

Then, the ball 1 is placed on a flat surface such as a paper surface.
When the ball-point pen tip 1 is tilted while the two are in contact with each other and the outside of the housing 5 contacts the plane, the housing 5 and the ball 12 simultaneously contact the plane.
The state at this time is the writing state, in which the ball-point pen tip is most inclined, and the virtual plane A and the ball-point tip 1
The angle with respect to the axis B is the minimum writable angle α. In this embodiment, the minimum writable angle α is about 49 °.

The housing 5 in the first embodiment is
The virtual plane A and the housing 5 are in contact with each other at a contact point 22, and the contact point 22 has a curved surface. The minimum writable angle α is 50 ° or less. That is, the contour line of the portion of the contact point 22 in the vertical cross section of the housing 5 is a curve. Therefore, even if the ball-point pen tip 1 is tilted during writing, the minimum writable angle α is as small as 50 ° or less, so that it is difficult to contact the surface of the paper as the writing material. Even when the housing 5 contacts the paper, the contour line of the contact point 22 in the vertical cross section of the housing 5 is a curve, and the contact point 22
Since it has a curved surface, it does not feel caught. The contact point 22 is the tip of the housing 5, and the housing 5
Since the contour line from the tip to the contact point 22 is a curved line or a straight line, even if the writing material deforms and enters the inside of the virtual plane A, there is no catching feeling, and a good writing feeling is obtained.

Further, in this embodiment, the ball diameter D is 0.
Although it is 5 mm, when the ball diameter D is small, it is an effective means for obtaining a good writing feeling. That is, even if the ball diameter D becomes small, the ball holding portion thickness W of the housing needs to have a strength to withstand the writing pressure.
A certain thickness or more is required. However, when the ball diameter D is small, the thickness W of the ball holding portion is relatively large, so that the minimum writable angle α is large. Therefore, although the housing 5 is likely to come into contact with the surface of the paper even with the same inclination, the contact point 22 has a curved shape, so that there is no feeling of being caught and a good writing feeling is obtained.

The ball-point pen tip 2 in the second embodiment is shown in FIGS. 4 (a) and 4 (b). The ball-point pen tip 2 is composed of the ball 12 and the housing 6 similarly to the ball-point pen tip 1 in the first embodiment, and is the same as the ball-point pen tip 1 except for the caulking portion 31 of the housing 6. The caulking portion 31 of the ball-point pen tip 2 has three corners 25, and the angle of the corner 25 in the vertical cross section of the housing 6 is about 170 °. Second
The manufacturing process of the ball-point pen tip 2 in the embodiment of
Except for the caulking process, it is the same as the ball-point pen tip 1 of the first embodiment. And ballpoint pen tip 2
The caulking process is performed by using a caulking tool having no protrusions, which is the same as in the prior art, and caulking three times while changing the caulking angle by about 10 °. Therefore, the caulking portion 31 is shown in FIG.
It becomes the shape as shown in.

As shown in FIG. 4B, the contact point 22 of the ball-point pen tip 2 in the second embodiment is the second corner 25a from the tip side of the ball-point pen tip. Also,
The second corner 25a in the longitudinal section of the housing 6
The angle S of (contact point 22) is about 170 °. That is, since the contact point 22 has a polygonal line shape and the angle S of the housing 6 at the contact portion is 170 °, which is 150 ° or more, the feeling of being caught is less likely to occur. Further, the vertical cross section of the housing 6 at the contact point 22 is preferably 165 ° or more. Further, since the ball-point pen tip 2 is caulked in three stages, the amount of plastic deformation per one time becomes small and so-called burr hardly occurs. The minimum writable angle α is about 48 °, which is 50 ° or less.

The housing 6 in the second embodiment is
Similar to the housing 5 of the first embodiment, it does not easily come into contact with the surface of the paper, and even if the housing 5 comes into contact with the paper, there is no feeling of being caught, so that a good writing feeling can be obtained.

The housing 6 in the second embodiment is
It can also be manufactured by a manufacturing method different from the above-described manufacturing method. The other manufacturing method of the housing 6 is the same as the above manufacturing method except for the caulking process, and only the caulking process is different. That is, the caulking process of another manufacturing method of the housing 6 is performed by performing the same caulking as in the conventional technique once and then cutting the outside so as to have the shape of the housing 6.

The ball-point pen tip 3 in the third embodiment is shown in FIG. Ballpoint pen tip 3
Is composed of a ball 12 ′ and a housing 7 as in the ballpoint pen tip 1 of the first embodiment. Since the ball-point pen tip 3 has a larger ball diameter D than the ball-point pen tip 1 in the first embodiment, the height H of the ball 12 ′ protruding from the housing 7 when not writing is short and the height H is high. Ratio of ball to ball diameter (H /
D) is small. Specifically, it is as follows.

The diameter of the ball 12 'is 1.0 mm,
The diameter is larger than that of the ball 12 of the first embodiment. The size relationship among the inner diameter of the ink guide hole 14, the inner diameter of the rear hole 16, and the depth of the ball holding portion 11 is the same as that of the ballpoint pen tip 1 of the first embodiment. Further, the caulking portion 32 of the ball-point pen tip 3 is caulked inward, and the tip end side of the caulking portion 32 has a curved contour line in a vertical cross section. The height H of the ball 12 ′ protruding from the housing 7 when not writing is 0.28 mm,
The ratio (H / D) to the ball diameter D is 28%, which is 3
It is 0% or less. The minimum writable angle α is 53 °
Is.

The ball-point pen tip 3 in the third embodiment is a large-diameter ball having a ball 12 'diameter D of 0.8 mm or more, and the ratio of the height H to the ball diameter D (H /
D) is small, and the minimum writable angle α is large. Therefore, when writing with the ball-point pen tip 3 tilted, the surface of the paper and the ball-point pen tip 3 are likely to come into contact with each other, but the contact point 22 has a curved contour line in the vertical cross section, and thus the writing feeling is good.

The ball-point pen tip 4 in the fourth embodiment is shown in FIG. The ball-point pen tip 4 comprises a ball 12, a housing 8 and a spring 27, and the housing 8 is the same as the housing 5 of the ball-point pen tip 1 in the first embodiment except for the caulking portion 33.

The spring 27 is located behind the ball 12,
The ball 12 is biased toward the protruding side. More specifically, the spring 27 is a cylindrical metal rod, one of which contacts the rear end side of the ball 12 and the other of which is a spring fixing portion (not shown) behind the rear hole 16 of the housing 8. It is fixed at. Then, after the ball 12 is held by caulking the tip of the housing 8, the ball 12 is in a state of protruding toward the tip side and the spring 27 is compressed and bent, as shown in FIG. .

Further, the caulking portion 33 of the ball-point pen tip 4
Is caulked inward, and further has a contact point 22 on the tip side of the caulking portion 33, and the contour line of the vertical cross section of the contact point 22 is a curve. After the caulking, the caulking is performed so that the ball 12 can move in the axial direction.

Since the ball-point pen tip 4 in the fourth embodiment is constructed as described above, the ball 12 is moved to the rear end side by the pressing of the ball 12 performed at the time of writing. That is, when the ball 12 is not pressed from the tip side, it is positioned on the tip side by the spring 27. When the ball 12 is pressed from the tip side and the pressing force is larger than the repulsive force of the spring 27, the spring 27 is further deformed and the ball 12 moves to the rear end side.

In this way, the ball 12 moves to the rear end side during writing, and the clearance 20 between the housing 8 and the ball 12 is increased.
In the case of a type with a large ink, especially when the ink has a high viscosity or when a solid is added to the ink, the outflow of the ink is improved and the ink runs out less, and when the writing is not performed, the gap 20 Has the advantage of less ink leakage, but the housing 8 of the ball 12
The height H ′ of the portion protruding from the height was smaller than the height H when not writing, and the minimum writable angle α was small, and the housing was likely to contact the surface of the paper during writing.

However, in the ball-point pen tip 4 according to the fourth embodiment, the contact point 22 has a curved contour line in the vertical cross section of the housing 8, so that the writing feeling is good.

Next, another method for manufacturing the ball-point pen tip 1 will be described. The method for manufacturing the ballpoint pen tip 1 is
The process up to the insertion of the ball 12 is the same as that of the first embodiment, but the steps after caulking are different. Similar to the first embodiment, the ball 12 is inserted, and then the tip of the ballpoint pen tip is brought into close contact with the ball 12 and caulked.
The outside of the tip of the housing 5 is ground to remove the corners.
Further, as shown in FIG. 7, the ball 12 is manufactured by pressing the ball 12 from the tip end direction with the pressing tool 45. When pressed, the bearing surface 17 of the housing 5 is plastically deformed and recessed, so that a gap 20 is formed between the housing 5 and the ball 12.

According to this manufacturing method, since there is no gap between the ballpoint pen tip 1 and the ball 12 when the outside of the ballpoint pen tip 1 is polished, even if a force is applied to the ballpoint pen tip 1 on the ball side, The corners can be removed by polishing or the like without making the gap between the ball 1 and the ball 12 uneven.

Further, other means for removing the corner is not limited to the above-mentioned polishing, but there is a method of removing the corner by a blade or a file, a method of removing it by an etching treatment (electrolytic treatment), and the like. Then, by any of these methods, the interval between the ballpoint pen tip 1 and the ball 12 does not become uneven.

[0065]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it is difficult to contact the surface of paper even when the ballpoint pen is tilted to write, and even if the surface of paper is contacted, there is little feeling of being caught. Even if it is deformed by the writing pressure, it does not cause a feeling of being caught, and good writing comfort can be obtained. Also,
An accurate ballpoint pen tip can be manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view of a ball-point pen tip according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the ball-point pen tip according to the first embodiment of the present invention when caulking.

FIG. 3 is an enlarged cross-sectional view of a caulking portion at the time of caulking the ball-point pen tip according to the first embodiment of the present invention.

FIG. 4A is a cross-sectional view of a ballpoint pen tip according to a second embodiment of the present invention, and FIG. 4B is an enlargement of an inclined writing contact portion of the ballpoint pen tip according to the second embodiment of the present invention. FIG.

FIG. 5 is a sectional view of a ball-point pen tip according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a ball-point pen tip according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view when pressing with a pressing tool during manufacturing of the ball-point pen tip according to the first embodiment of the present invention.

FIG. 8 is a cross-sectional view of a ballpoint pen according to the related art.

FIG. 9 is an explanatory diagram showing a usage state of a writing instrument.

FIG. 10 is a cross-sectional view of a ballpoint pen tip according to a conventional technique.

FIG. 11 is a cross-sectional view of a ball-point pen tip in another example of the related art.

FIG. 12 is an enlarged cross-sectional view of the tip of the ball-point pen tip when the writing material is deformed when the ball-point pen tip in the prior art is used.

FIG. 13A is an enlarged view of a caulking portion of a ballpoint pen tip according to an example of the related art, and FIG.
FIG.

FIG. 14A is an enlarged view of a caulking portion of a ballpoint pen tip in another example of the related art, and FIG. 14B is an enlarged view of FIG.

[Explanation of symbols]

1,2,3,4 ballpoint pen tip 5,6,7,8 housing 11 Ball holder 12,12 'ball 20 gap 22 Contact point 25 angle 27 springs 30, 31, 32, 33 Caulking part

Claims (10)

[Claims] 1. A ball-point pen tip having a ball and a stainless steel housing and rotatably holding the ball in the housing, wherein the ball-point pen tip is tilted while the ball is pressed against the plane, and the housing is placed on the plane. A ball-point pen tip, characterized in that, when brought into contact with each other, a contour line of the contact portion in a vertical cross section of the housing is curved, linear, or bent at 150 ° or more. 2. The ball-point pen tip according to claim 1, wherein the ball has a diameter of 0.5 mm or less. 3. The ballpoint pen tip according to claim 1, wherein the height H of the portion of the ball protruding from the housing when not writing is less than 30% of the diameter D of the ball. 4. A ball-point pen tip having a ball and a housing, and rotatably holding the ball in the housing, wherein the ball has a diameter D of 0.8 mm or more,
The height H of the portion of the ball protruding from the housing when not writing was less than 30% of the diameter D of the ball, and the ballpoint pen tip was tilted while the ball was pressed against the flat surface to bring the housing into contact with the flat surface. In this case, the ball-point pen tip is characterized in that a contour line of the contact portion in a vertical cross section of the housing is a curved line, a straight line, or a bent line of 150 ° or more. 5. The contour line between the tip of the housing and the contact portion of the housing in the vertical cross section of the housing is a curved line, a straight line, or a polygonal line composed of corners of 150 ° or more. The ball-point pen tip according to any one of 1 to 4. 6. An angle between the axis of the ball-point pen tip and the plane when the ball-point pen tip is tilted while the ball is pressed against the plane and the housing is brought into contact with the plane is 50 ° or less. Item 6. A ball-point pen tip according to any one of items 1 to 5. 7. The urging means for urging the ball toward the protruding side is provided behind the ball inside the housing, and the ball is movable in the axial direction.
The ballpoint pen tip according to any one of 1. 8. The thickness W of the ball holding portion of the housing is 20 μm to 50 μm in a plane that passes through the center of the ball and is perpendicular to the axis of the ballpoint pen tip with the ball pressed against the plane as a reference. The ballpoint pen tip according to any one of claims 1 to 7. 9. The method of manufacturing a ball-point pen tip according to claim 1, wherein the ball is inserted into the housing, the open end of the housing is brought into close contact with the ball and caulked, and then the outer surface of the housing is covered. A method for manufacturing a ball-point pen tip, characterized in that a corner is removed, and thereafter, the ball is pressed from the tip direction toward the housing side. 10. A method of manufacturing a ball-point pen tip having a ball and a stainless steel housing, wherein the ball is rotatably held in the housing, wherein the ball is inserted into the housing and the open end of the housing is formed into the ball. A method for manufacturing a ball-point pen tip, which comprises contacting and caulking, removing an outer corner of the housing, and then pressing the ball from the tip direction toward the housing.