JP2000211284A - Metal tip for oil-based ballpoint pen - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a metal ball-point pen tip that is less likely to be flared at the start of writing and a backflow state. [Structure] The ink guide hole (20) on the side of the back hole (60) in the ball house (10), the radial groove (30) around the ink guide hole (20), and the ball (60) rotate smoothly. The diameter of the radial groove (30) is in the range of 100% to 110% of the diameter of the ball receiving seat (40). I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal ballpoint pen used in an oil-based ballpoint pen.

[0002]

2. Description of the Related Art FIG. 2 shows a general metal tip for a conventional ballpoint pen. In the metal tip for a ballpoint pen shown here, a wire material such as stainless steel as a material is processed from both ends. First, a step of cutting into a predetermined length, a step of forming an outer shape of the cut wire, and a step of forming an inner shape are performed.

[0003] In the formation of the inner shape, the ball house 10 is used to hold the ball 70 that fits into the tip of the chip.
And In addition, in order to hold the ball 70 so that the ball 70 can rotate smoothly, the inner surface is finished to form a ball receiving seat portion 40. In order to guide ink to the ball house 10,
A back hole 60 is provided to penetrate the ball house 10 from the opposite side. An ink guide hole 20 for guiding the ink to the vicinity of the ball 70 and a radial groove 30 for guiding the ink to an ink pool 50 for storing the ink actually used for writing are provided.

[0004] Usually, the diameter (φD) of the radial groove 30 is empirically set to 1 with respect to the diameter (φC) of the ball receiving seat 40.
It was often in the range of 15% to 130%.

[0005]

However, the above technique has the following problems. That is, in actual writing, the rotation of the ball 70 entrains air into the ink reservoir 50. If the entrained air enters deep into the ink guide holes 20 and the radial grooves 30, it is difficult to discharge the air.

If the chip is left facing upward in the presence of air that is not discharged, the ink guide holes 20 and the radial grooves 3
0 ink returns to the back hole 60. Then
When writing next time, there is no ink in the radial groove 30 so that blurring occurs at the beginning of writing. In a more extreme case, the ink in the tube fitted to the rear end of the chip may fall to the rear end of the tube. In such a case, a state where the ball-point pen cannot be used (hereinafter, referred to as a “backflow state”) also occurs.

An object to be solved by the present invention is to provide a metal ballpoint pen tip technology which makes it difficult to cause a blur or a backflow state at the start of writing. Here, an object of the invention described in claims 1 and 2 is to provide a metal ball-point pen tip which is less likely to be flared at the start of writing and a backflow state.

[0008]

SUMMARY OF THE INVENTION The present invention is to achieve the above object. (Claim 1) The invention according to claim 1 is a ball house (10).
The ink guide hole (20) on the side of the back hole (60), the radial groove (30) centered on the ink guide hole (20), and the ball (6).
In the metal tip for oil-based ballpoint pens provided with a ball receiving seat (40) for smoothly rotating
The diameter of (30) is 10 times the diameter of the ball seat (40).
The range is 0% to 110%.

(Definition of terms) An oil-based ballpoint pen is generally one in which the ink satisfies the condition of 3000 to 15000 cps.
It may be in the range of ~ 3000 cps. The metal referred to as the material of the pole pen tip holder includes, for example, various stainless steels, titanium alloys, aluminum alloys, copper alloys such as nickel silver, phosphor bronze, and brass.

The ball is formed of a material such as a metal such as cemented carbide or stainless steel, or a material such as ceramic such as zirconia or silicon carbide. The diameter of the radial groove (30) is 100% to 1 of the diameter of the ball receiving seat (40).
It is claimed that the range is 10%, but it is more preferably 103% to 106%. 103%
If it is less than or equal to 106%, no backflow occurs, and the blurring length at the start of writing is extremely short.

(Function) Since the diameter of the radial groove (30) is appropriate for the diameter of the ball receiving seat (40),
It is unlikely that the radial groove (30) has no ink.
Therefore, it is unlikely that the beginning of writing or the backflow state will occur.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments and drawings. The drawing used here is FIG. FIG. 1 is a longitudinal sectional view and a transverse sectional view showing an embodiment of the present invention. The tip body, which is the tip of the ballpoint pen, is formed from a stainless steel wire rod as a material from both ends. As a material of the wire, a metal material such as a copper alloy and a titanium alloy may be used in addition to stainless steel.

The material of the ball 70 is a cemented carbide. 3000 to 15000 cps as ink
An oil-based ink that satisfies the above condition was adopted. As in the prior art, in the present embodiment, the ball house 10 holds the ball 70 that fits into the tip of the chip. Further, in order to guide the ink to the ball house 10, a back hole 60 is provided to penetrate the ball house 10 from the opposite side.

In order to guide the ink while holding the ball 70 in the ball house 10, the radial groove 3 is inserted into the ball receiving seat 40 existing between the back hole 60 and the ball house 10.
0 is provided, but broaching is performed to form the radial groove 30. The diameter (φB) of the radial groove 30 and the diameter (φA) of the ball receiving seat portion 40 were appropriately changed, and a backflow experiment was performed by the following method. Table 1 shows the results.

[0015]

[Table 1]

Here, the "number" of the "backflow test"
The term “number” refers to the number of balls that have flowed back to 100 ball-point pen tips under the same conditions such as the ball diameter, receiving seat diameter, radiation groove diameter, and ink type. The test is performed as follows. First, the sample is written freehand on 20 rounds of a spiral having a diameter of about 20 mm, and the pen tip is set up. Next, the sample is put in a decompression chamber in that state, the pressure is reduced to 15 mmHg, and the sample is left for 5 minutes. After leaving to stand, the pressure is returned to the original pressure, and the ink that has leaked from the rear end of the refill is recognized as "backflow". It was confirmed by visual observation that a large amount of air accumulated in the chip easily caused backflow.

[0017] The "shear length at the start of writing" is an average value for ten ballpoint pen tips under the same conditions such as a ball diameter, a seat diameter, a radiation groove diameter, and an ink type. is there. The test is performed as follows. First, the sample is written freehand on 20 rounds of a spiral having a diameter of about 20 mm, and the tip is left standing for 1 hour with the pen pointed upward. Then, after leaving, the spiral is written freehand, and the length of the sharpened portion at the start of writing is measured with a free ruler.

(Conclusion derived from Table 1) As is apparent from Table 1, the diameter (φB) of the radial groove 30 is 100% to 110% of the diameter (φA) of the ball receiving seat portion 40.
In the range, the backflow did not occur, and the bleeding length at the start of writing could be made as short as possible.
More effectively, the diameter (φB) of the radial groove 30 is 103% to 106% of the diameter (φA) of the ball receiving seat portion 40. This is because, as shown in Table 1, the rubbing length at the start of writing can be 1 mm or less.

Table 1 does not describe the case where the diameter (φB) of the radial groove 30 is less than 100% of the diameter (φA) of the ball receiving seat 40. This is because, although an experiment was conducted, it was confirmed that there was a problem in the supply of ink, the writing followability was deteriorated, and the device was not practical. (Relation between Ball Diameter and Depth of Radiation Groove) The depth of the radiation groove with respect to the ball diameter is preferably in the range of 10% to 30%. More preferably, it is 15% to 25%.

If it is less than 10%, the ejection of ink becomes worse and the rubbing length at the start of writing increases. On the other hand, if it is larger than 30%, the backflow of the ink tends to occur, which is not practical. If it is 10% to 30%, the bleeding length at the start of writing is short, but no ink backflow occurs. 15% to 25
%, The backflow of the ink does not occur, and the blurring length at the start of writing is extremely short, that is, 1 mm or less.

[0021]

According to the first aspect of the present invention, it is possible to provide a metal ball-point pen tip which is less likely to be blurred at the start of writing and a backflow state.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view and a transverse sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Ball house 20 Ink guide hole 30 Radial groove 40 Ball receiving seat part 50 Ink pool 60 Back hole 70 Ball

Claims (1)

[Claims] An ink guide hole on a back hole side of a ball house, a radial groove centered on the ink guide hole,
In a metal tip for an oil-based ball-point pen provided with a ball receiving seat for smoothly rotating a ball, the diameter of the radial groove is in the range of 100% to 110% of the diameter of the ball receiving seat. Metal tip for oil-based ballpoint pens.