JP2003048393A - Ball point pen tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball point pen tip, by which no writing blurring develops in the change of a writing direction, the discharge of ink is smooth and, in addition, neither ink dripping phenomenon nor irruption of foreign matter through a writing tip part develops. SOLUTION: By forming a ball receiving seat 13a1 and a side face seat part 13b on the lines of the surface of a transfer ball 20 by setting the ratio of the maximum diameter of the ball receiving seat 13a1 to the inner diameter of a ball house 13 in the range of about 70 to 90% between the site on the end side hinderer than the midway site in the inner side surface of the ball house 13 and the surface of the transfer ball 20 and between the bottom surface 13a of the ball house 13 and the surface of the transfer ball 20, an ink well space part 16 for temporarily storing a proper amount of ink therein is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball-point pen tip which rotatably holds a transfer ball in a ball house.

[0002]

2. Description of the Related Art Conventionally, this type of ball-point pen tip rotatably holds a transfer ball inserted in a ball house by crimping the front end of the tip.
Immediately after writing or at the time of display, so-called ink dripping phenomenon in which ink flows out from the tip of the writing, the phenomenon that the transfer ball is caught in the ball house by foreign substances such as paper fibers, the transfer ball rotates unstable when the writing direction is changed. By doing so, there may be various problems such as a phenomenon that blurring of writing occurs. Therefore, in the ballpoint pen tip disclosed in Japanese Patent Publication No. 5-64120, the front end side of the tip is caulked in two steps, so that the first gap 5 is formed on the front end side between the inner surface of the ball house and the transfer ball. (Refer to FIG. 1 of the publication), a second void portion 7 is formed on the rear side thereof, and the ink is returned by the first void portion 5 and the second void portion 7. Therefore, the ink dripping phenomenon is prevented. Further, Japanese Patent Laid-Open No. 3-230
In the ballpoint pen tip disclosed in No. 21, by caulking the tip front end in two steps, the gap between the front end portion on the inner surface of the ball house and the transfer ball is reduced, and the transfer ball transfers foreign matter such as paper fibers to the ball. We try to prevent the phenomenon of being caught in the house.

However, in the prior art disclosed in the former publication, there is a case where the foreign matter that has entered from the first gap 5 is caught in the second gap 7 and the ejection of ink is hindered. Further, in the related art disclosed in the latter publication, there is a concern that the volume of the ink storage space for temporarily storing ink on the bottom surface side of the ball house cannot be sufficiently secured, and writing blurring may occur. Further, in any of the above-mentioned prior arts, when the writing pressure is small and smooth handwriting is to be obtained by setting the ball diameter of the transfer ball to be relatively large,
It was difficult to prevent all phenomena such as blurring of writing, ink dripping, and entry of foreign matter from the tip of writing.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and its problem is that even if the ball diameter of the transfer ball is increased to obtain smooth handwriting with a small writing pressure, An object of the present invention is to provide a ball-point pen tip which is free from writing blurring, has a smooth ink ejection, and is free from ink dripping phenomenon and foreign matter from the writing tip.

[0005]

Means for Solving the Problems The technical means of the present invention for solving the above-mentioned problems is to press a transfer ball inserted into a ball house to cause the surface of the transfer ball on the bottom surface of the ball house. A ball receiving seat consisting of an indentation conforming to is formed, further, by performing a two-step caulking process on the outer periphery of the front end side of the chip body, a first caulking portion and a second caulking portion are formed, and with this, A ballpoint pen tip formed on the inner side surface of the ball house, the side surface seat portion extending from the midway portion to the frontmost end portion following the surface of the transfer ball, and a portion on the rear end side of the midway portion of the inner side surface of the ball house. Between the bottom surface of the ball house and the surface of the transfer ball, the ratio of the maximum diameter of the ball seat to the inner diameter of the ball house is set within the range of about 70 to 90%. Wherein the ink reservoir space for temporarily reserving an appropriate amount of ink is ensured.

According to the above technical means, the ball receiving seat on the bottom surface of the ball house is formed in an arcuate cross-section that follows the surface shape of the transfer ball due to the indentation due to the pressing of the transfer ball. Further, the side surface seat portion, by the two-stage caulking process, to form the first caulking portion and the second caulking portion, along with it, the inner surface of the ball house, the range from the midway portion to the frontmost portion, It is plastically deformed into a shape that follows the surface of the transfer ball. Therefore, the transfer ball comes into contact with the ball receiving seat with a uniform surface pressure, and also comes into contact with the side surface seat portion with a uniform surface pressure. In addition, the ink reservoir space is formed to have a volume that stores an appropriate amount of ink by setting the ratio of the maximum diameter of the ball receiving seat to the inner diameter of the ball house within the above range, that is, the ink ejection is smooth. In addition, the volume is formed so as not to cause ink dripping.

In order to stabilize the rotation of the transfer ball during writing, the opening angle of the bottom surface of the ball house is set within the range of about 80 to 120 degrees.

Further, in order to surely prevent foreign matter from penetrating from the writing tip portion and ink dripping during writing, the crimping angle of the first crimping portion is set within a range of about 45 to 60 degrees, and The crimping angle of the second crimping portion is set within a range of approximately 80 to 110 degrees.

Further, in order to obtain a smooth handwriting with a small writing pressure, it is conceivable to increase the ball diameter of the transfer ball. Preferably, the ball diameter of the transfer ball is set to about 0.5 to 2.0 mm. To do.

Further, in order to prevent ink drip more reliably, a biasing member for biasing the transfer ball forward is provided behind the transfer ball.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show an example of a ballpoint pen tip according to the present invention. This ballpoint pen tip A
Is a ball house 13 formed at the front end of the chip body 10.
The transfer ball 20 is rotatably held therein.

The tip body 10 has a substantially conical shape on the front end side, and a ball house 13 is formed in the front end portion by cutting. The angle β on the front end side of the unprocessed chip body 10 is formed to be about 14 degrees (see FIG. 2).
(See (a)), after the transfer ball 20 is inserted into the ball house 11 and pressed, an indentation (ball receiving seat 13a1) is formed on the bottom surface 13a of the ball house 13, and then two-step caulking is performed. Thus, the first caulking portion 11 and the second caulking portion 12 are formed near the front end portion (see FIGS. 3C and 3D).

The opening angle θ of the bottom surface 13a of the ball house 13 is set within the range of about 80 to 120 degrees, preferably about 90 degrees. When the opening angle θ is larger than the above range, the difference in the ink ejection amount depending on the rotation direction of the transfer ball 20 is likely to occur, and the ink ejection amount becomes too large. Further, when the opening angle θ is smaller than the above range, the area where the ink guide groove 15 is blocked by the transfer ball 20 increases, so that the ink ejection amount becomes too small and writing blurring easily occurs. Will end up. And
On the axial center side of the bottom surface 13a, an indentation by the transfer ball 20 inserted into the ball house 13 and pressed forms a ball receiving seat 13a1. The ball receiving seat 13a1 has an arc-shaped cross section formed following the surface of the transfer ball 20. Therefore, the contact pressure that contacts the transfer ball 20 is made substantially uniform, and the rotation of the transfer ball 20 is stabilized.

The range of the opening angle θ of the bottom surface 13a is set so that the rotation of the transfer ball 20 is stable during writing. That is, when the opening angle θ is larger than the above range, an angle θ ′ between the perpendicular lines of the transfer balls 20 contacting the bottom surface 13a of the ball house 13 (FIG. 2A).
Transfer ball 20 that becomes smaller and rotates during writing.
The rotation becomes unstable due to the large vibration in the horizontal direction. Further, when the opening angle θ is smaller than the above range, the sandwiching angle θ ′ between the perpendicular lines of the transfer balls 20 in contact with the bottom surface 13a of the ball house 13 becomes large, and the transfer balls 20 are sandwiched. The frictional resistance between the transfer ball 20 that rotates during writing and the ball receiving seat 13a1 becomes too large, and the transfer ball 20 will not rotate smoothly.

The maximum diameter a of the ball receiving seat 13a1 is about 70 to 90% of the inner diameter b of the ball house 13.
In the preferred example of the present embodiment, the maximum diameter a of the ball receiving seat 13a1 is defined as follows.
The ratio is about 74% with respect to the inner diameter b of the ball house 13.

By forming the maximum diameter a of the ball receiving seat 13a1 within the above range, a portion of the inner surface of the ball house 13 on the rear end side of the midway portion, a bottom surface 13a of the ball house 13, An ink storage space 16 for temporarily storing an appropriate amount of ink is secured between the surface of the transfer ball 20 and the surface.

The ink reservoir space 16 temporarily stores ink and supplies it to the transfer ball 20 so as to follow the ink drawn by the rotation of the transfer ball 20 during writing. When the maximum diameter a of the ball receiving seat 13a1 is larger than the above range, the ink reservoir space portion 16 becomes too narrow, so that the amount of ink supplied to the writing tip portion at the time of writing decreases and ink spillage occurs. It tends to occur. Further, since the contact area between the ball receiving seat 13a1 and the transfer ball becomes large, the writing feeling becomes heavy. When the maximum diameter a of the ball receiving seat 13a1 is smaller than the above range, the ink reservoir space portion 16 becomes too wide, and the amount of ink temporarily stored becomes too large, which easily causes ink drip. Since the contact area between the ball receiving seat 13a1 and the transfer ball 20 becomes small, the rotation of the transfer ball 20 becomes unstable, and the difference in the ink ejection amount depending on the rotation direction of the transfer ball 20 easily occurs.

In addition, an ink guide hole 14 for guiding ink from an ink tank (not shown) is formed in the center of the bottom surface 13a of the ball house 13, and a flat surface is formed on the bottom surface 13a of the ball house 13. A plurality of ink guide grooves 15 are radially formed (see FIG. 4). The ink guide groove 15 is pressed by the transfer ball 20 inserted into the bottom surface 13a of the ball house 13 to form a ball receiving seat 13a.
After the indentation No. 1 is formed, as shown in FIG. 5, the plan view shape thereof has a tapered shape toward the ink guide hole 14.

After the ball receiving seat 13a1 which is an indentation by the transfer ball 20 is formed in the ball house 13 as described above, the first caulking portion 11 is formed on the front end side of the chip body 10 by caulking. Further, the second caulking portion 12 on the front end side of the first caulking portion 11 is formed.

As shown in FIG. 3C, the first caulking portion 11 is formed by caulking the front end side of the chip body 10 with a caulking roller or the like, and the caulking angle α1 is about 45.
It is formed so as to fall within a range of -60 degrees, preferably about 48 degrees. If the crimp angle α1 is larger than the above range, the difference in the ink ejection amount depending on the rotation direction of the transfer ball 20 is likely to occur, and the ink ejection amount becomes too large. Further, when the crimping angle α1 is smaller than the above range, ink dripping is likely to occur (see Table 2).

As shown in FIG. 3D, the second caulking portion 12 is formed by caulking the front end side of the first caulking portion 11 with a caulking roller or the like, and the caulking angle α2 is
It is formed to have a range of about 80 to 110 degrees, preferably about 100 degrees. If the caulking angle α2 is larger than the above range, caulking of the second caulking portion 12 is difficult in manufacturing, and if the caulking angle α2 is smaller than the above range, ink drip is likely to occur. (See Table 3).

Then, by the two steps of caulking,
On the inner side surface of the ball house 13, a side surface seat portion 13b that follows the surface of the transfer ball 20 is provided in a range from the midway portion to the inward tip edge 13b1 of the frontmost end portion (range of arcuate dimension w shown in FIG. 1). It is formed.

The side surface seat portion 13b has the inner surface of the ball house 13 formed by the two-step caulking process as described above.
It is formed by plastic deformation in an arc shape after becoming 0. Therefore, the transfer ball 20 comes into contact with the side surface seat portion 13b with a uniform surface pressure.

Then, the transfer ball 20 and the side seat portion 13b
Since there is almost no gap between the front end and the inward leading edge 13b1 of the front end, foreign matter such as fibers on the paper surface is not caught during writing.

The diameter of the transfer ball is appropriately selected according to the use, but conventionally, the diameter is generally 0.
It was 5 to 1.2 mm. However, for those with diameters larger than this range or those with smaller diameters, although there were some specifications, there was a limit to the processing of the chip body that could be effectively used, and it was not implemented. Is the current situation. According to the present invention, it is possible to obtain the above-mentioned chip body 10 which can solve the problems such as the writing blurring phenomenon, the ink dripping phenomenon, and the entrainment phenomenon of foreign matter, which are caused by the increase in the diameter of the transfer ball 20. And
The diameter of the transfer ball 20 of the present embodiment is in the range of about 0.5 to 2.0 mm based on the relationship with the chip body 10, and a transfer ball 20 having a particularly preferable diameter is about 0.7 to. It is in the range of 1.6 mm, most preferably about 1.2 to 1.6 mm.

Further, as shown in FIG. 6, the chip body 10
On the rear side of the transfer ball 20 inside, the transfer ball 2
Urging member 30 for urging 0 forward, and the urging member 30
A receiving member 40 for receiving the rear end portion is provided. The urging member 30 is a compression spring, and by pressing the transfer ball 20 against the side surface seat portion 13b, ink dripping can be prevented more reliably.

The ball-point pen tip A having the above-mentioned structure is applicable to both oil-based ball-point pens and water-based ball-point pens, but is particularly suitable for a ball-point pen filled with so-called shear thinning ink.

Next, the result of the ink dripping confirmation test of the ball-point pen tip A having the above structure will be described. In this test, the front end side of the tip body 10 was crimped only once at an angle of 48 degrees (hereinafter referred to as "single-step crimping"), and the front end side of the tip body 10 was angled as in the above embodiment. After caulking at about 48 degrees, the angle is about 1
Caulking at 00 degrees (hereinafter referred to as "two-step caulking")
Prepared ballpoint pen tips, and each of these two types of ballpoint pen tips is given a different ink color (black, blue, red).
A total of 6 types of ball-point pens (samples 1 to 6) are configured by mounting each of the 3 types of oil-based ball-point pens, and 100 tests are performed on each sample.

The test method is as follows. An oil-based ballpoint pen equipped with the above-mentioned ballpoint pen tip A is used at a temperature of 30 degrees and a humidity of 80.
%, After being left for 72 hours in a suspended state in a hollow state, it is confirmed whether or not ink is dripping at the tip of the writing.

The results of the above tests are shown in Table 1 below.

[Table 1]

As a result of the above-mentioned test, as shown in Table 1, 30 out of 100 in the sample 1 of the one-step caulking and black ink, 79 out of 100 in the sample 2 of the one-step caulking and the blue ink,
In sample 3 of the first-stage caulking and red ink, ink dripping was confirmed in 56 out of 100 inks. In addition, no ink dripping was confirmed in the two-step caulking samples 4 to 6.

In other words, ink dripping occurred in the first-stage caulking samples 1-3, but the second-stage caulking samples 4-6.
The result is that ink dripping does not occur.
In addition, it is considered that the difference in the number of occurrence of ink dripping due to the difference in ink color was caused by the difference in ink viscosity between the first to third-stage caulked samples 1-3.

Next, with respect to the ball-point pen tip A having the above-mentioned structure, the result of the test for confirming how the number of ink dripping changes depending on the difference in the caulking angle α1 will be described. In this test, three types of ballpoint pen tips having different swaging angles α1 and 70 ° of swaging angles were prepared, and each of these three types of ballpoint pen tips was used with three different ink colors (black, blue, red). By attaching to each of the oil-based ballpoint pens, a total of 9 types of ballpoint pens (Sample 19
~ 27), and 100 tests are conducted for each sample.

In this test, an oil-based ballpoint pen equipped with the above-mentioned ballpoint pen tip A was tested at a temperature of 30 degrees and a humidity of 80.
%, After being left for 72 hours in a suspended state in a hollow state, it is confirmed whether or not ink is dripping at the tip of the writing.

The results of the above tests are shown in Table 2 below.

[Table 2]

As a result of the above test, as shown in Table 2, samples 19 to 21 having a caulking angle α1 of 40 degrees produced a total of 15 ink drops, and samples 22 to 22 having a caulking angle α1 of 48 degrees.
In No. 24, a total of two ink sags occurred, and in Samples 25 to 27 with a caulking angle α1 of 55 degrees, a total of three ink sags occurred.

That is, the crimping angle α1 is 48 degrees and 5
In the case of the 5 ° sample, almost no ink dripping was caused, and particularly when the crimping angle α1 was 48 °, the ink dripping was smallest. It is considered that the difference in the number of ink drips due to the difference in ink color is due to the difference in ink viscosity.

Next, with respect to the ball-point pen tip A having the above-mentioned structure, the result of a test for confirming how the number of ink dripping changes depending on the difference in the caulking angle α2 will be described. In this test, four types of ballpoint pen tips having a swaging angle α1 of 48 degrees and different swaging angles α2 were prepared, and each of the four types of ballpoint pen tips was tested with three different ink colors (black, blue, red). A total of 12 types of ballpoint pens (samples 7-1
8) is configured and 100 pieces of each sample are tested.

In this test, an oil-based ballpoint pen equipped with the above-mentioned ballpoint pen tip A was tested at a temperature of 30 degrees and a humidity of 80.
%, After being left for 72 hours in a suspended state in a hollow state, it is confirmed whether or not ink is dripping at the tip of the writing.

The results of the above tests are shown in Table 3 below.

[Table 3] As a result of the above-mentioned test, as shown in Table 3, two ink sags occur in Samples 7 to 9 having a caulking angle α2 of 70 degrees, and one ink sagging occurs in Samples 10 to 12 having a caulking angle α2 of 80 degrees. , Sample 13 with the same crimping angle α2 of 90 degrees
No. 15 causes one ink sag, and Samples 13 to 15 having the same caulking angle α2 of 90 degrees cause one ink sag.
In Samples 16 to 18 having the same crimping angle α2 of 100 degrees, no ink dripping occurred.

That is, in the sample having the crimping angle α2 of 80 or more, almost no ink dripping occurred. It is considered that the difference in the number of ink drips due to the difference in ink color is due to the difference in ink viscosity.

Next, another example of the ball-point pen tip according to the present embodiment will be described. This ballpoint pen tip B
In the ball-point pen tip A having the above-described configuration, the shape of the front end side of the tip body 10 ′ before caulking and the opening angle θ of the bottom surface 13a of the ball house 13 are changed. In the description, the same components as those of the ball-point pen tip A will be denoted by the same reference numerals and redundant description will be omitted.

As shown in FIG. 7A, the tip body 10 'has an angle β1 of the outer peripheral surface on the front end side before caulking.
(Rear side) is about 14 degrees, Angle β2 (Front side) is about 3
It is formed at 0 degrees. Then, the first caulking portion 11 and the second caulking portion 12 are formed in the portion having the angle β2 by the two-stage caulking processing (see FIG. 7B). At that time, the crimping angle α1 of the first crimping portion 11 and the crimping angle α2 of the second crimping portion 12 are set in the same manner as the ballpoint pen tip A described above. Therefore, as in the ballpoint pen tip A, the side surface seat portion 1 that is plastically deformed following the surface of the transfer ball 20 is provided in the ball house 13.
3b is formed.

The opening angle θ of the bottom surface 13a in the ball house 13 is set to about 120 degrees in the illustrated example. The opening angle θ is set within a range of about 80 to 120 degrees, as is the case with the ballpoint pen tip A, in order to further stabilize the rotation of the transfer ball 20.

When the transfer ball 20 is pressed, a ball receiving seat 13a1 which is an indentation conforming to the surface of the transfer ball 20 is formed on the bottom surface 13a of the ball house 13.
Is formed. The maximum diameter a of the ball receiving seat 13a1 is about 70 to 90 with respect to the inner diameter b of the ball house 13.
It is formed to be within the range of%.

[0046]

According to the present invention, since the ball receiving seat and the side surface seat portion are formed in a shape that follows the surface of the transfer ball, the front end portion (inward leading edge) of the side surface seat portion and the transfer ball are formed. The transfer ball comes into contact with the ball receiving seat and the side seat with a uniform surface pressure with almost no space between them. Also, by setting the maximum diameter ratio of the ball receiving seat,
The ink reservoir space is formed in a suitable volume. Therefore,
Due to these synergistic effects, the rotation of the transfer ball is stable, and when the writing direction is changed as well as at the time of writing, there is no blurring of writing and ink ejection becomes smooth. In addition, it is possible to prevent foreign matter from penetrating from the tip of the writing portion during writing, and prevent ink dripping immediately after writing or during display. Further, according to the aspect in which the opening angle of the bottom surface in the ball house is set, the rotation of the transfer ball can be more stabilized, and the blurring of writing when the writing direction is changed can be reliably prevented. Moreover, according to the aspect in which the caulking angle of the first caulking portion and the caulking angle of the second caulking portion are respectively set, the gap between the front end portion (inward leading edge) of the side surface seat portion and the transfer ball is made smaller. Since the contact pressure between the transfer ball and the side seat can be made more uniform, foreign matter can enter from the tip of the writing during writing, and ink drip immediately after writing or during display. Can be reliably prevented. Further, the mode in which the diameter of the transfer ball is set is particularly effective in preventing ink dripping. Furthermore, if a biasing member that biases the transfer ball forward is provided behind the transfer ball, ink dripping can be prevented more reliably.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an example of a ballpoint pen tip according to the present invention.

2A and 2B are cross-sectional views of a main part showing a manufacturing process of the ball-point pen tip, where FIG. 2A shows a state in which a transfer ball is inserted into a ball house, and FIG. 2B shows a ball receiving seat by pressing the transfer ball. The formed state is shown.

3A and 3B are cross-sectional views of a main part showing the manufacturing process of the ballpoint pen tip, in which FIG. 3C shows a state where the first caulking portion has been caulked, and FIG. 3D shows a state where the second caulking portion has been caulked. .

FIG. 4 is a sectional view taken along line (IV)-(IV) in FIG. 2, in which a transfer ball is omitted.

5 is a sectional view taken along line (V)-(V) in FIG.
The transfer ball is omitted.

FIG. 6 is a sectional view showing the entire ball-point pen tip.

FIG. 7 is a cross-sectional view of main parts showing a manufacturing process of another example of the ball-point pen tip according to the present invention, in which (a) is a state in which a ball receiving seat is formed by pressing a transfer ball inserted into a ball house. (B) shows a state in which the first caulking portion and the second caulking portion are caulked.

[Explanation of symbols]

10, 10 ': chip body 11: First caulking part 12: Second caulking part 13: Ball House 13a1: Ball seat 13b: Side seat 20: Transfer ball 16: Ink storage space 30: Energizing member A, B: Ballpoint pen tip a: Maximum diameter of ball seat α1: Caulking angle of the first caulking part α2: Caulking angle of the second caulking part θ: Angle of the bottom surface in the ball house

Claims (5)

[Claims] 1. A ball receiving seat made of an indentation conforming to the surface of the transfer ball is formed on the bottom surface of the ball house by pressing the transfer ball inserted into the ball house, and the front end of the chip body is further formed. By performing a two-stage caulking process on the side outer periphery, a first caulking portion and a second caulking portion are formed, and along with this, on the inner surface of the ball house, a side surface seat portion extending from the midway portion to the foremost end portion, A ball-point pen tip formed following the surface of the transfer ball, between the bottom surface of the ball house and the surface of the transfer ball, which is located on the inner side of the ball house on the rear end side of the intermediate part,
By setting the ratio of the maximum diameter of the ball receiving seat to the inner diameter of the ball house within a range of about 70 to 90%, an ink reservoir space for temporarily storing an appropriate amount of ink is secured. Ballpoint pen tip. 2. The ball-point pen tip according to claim 1, wherein an opening angle of the bottom surface of the ball house is set within a range of about 80 to 120 degrees. 3. The caulking angle of the first caulking portion is about 4
The ballpoint pen tip according to claim 1 or 2, wherein the crimping angle of the second crimping portion is set within a range of approximately 80 to 110 degrees while being set within a range of 5 to 60 degrees. 4. The diameter of the transfer ball is about 0.5 to
The ball-point pen tip according to any one of claims 1 to 3, wherein the ball-point pen tip is set within a range of 2.0 mm. 5. The ball-point pen tip according to claim 1, further comprising an urging member that urges the transfer ball forward, behind the transfer ball.