JPH07214969A - Chip of ball point pen - Google Patents

Abstract

PURPOSE:To restrain the phenomenon of handwriting break from occurring at an early stage by keeping the reduction of ink due to discharge low relative to the advance of a ball sink phenomenon. CONSTITUTION:An ink passage 6 opening at the ball retainer seat 5 of a ball point pen chip A comprises a central bore 6a and radial grooves 6b, and the width (x) of the minimum width 6c in the opening is made 12-35% long with respect to the diameter of a ball, and the radial grooves 6b are formed at an angle of 20-60 deg. toward the diameter outside direction of the ball retainer seat 5 from the minimum width 6c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A ball holding chamber for holding a ball as a writing member by partially forming an opening having a diameter smaller than the diameter of the ball at the tip end so as to hold the ball as a writing member. The box
The present invention relates to a ball pen tip formed by opening an ink passage radially formed radially outward from the vicinity of the center of the ball receiving seat portion.

[0002]

2. Description of the Related Art Conventionally, two types of ink passages for ballpoint pen tips are known. One of them is composed of a central hole having a relatively low capillary force and a radial groove having a relatively high capillary force and communicating with the central hole. The other one is that a plurality of independent fan-shaped ink passages are formed point-symmetrically.

An ink passage having the above-described central hole and radial grooves communicating with the central hole is disclosed in Japanese Patent Publication No. 54-1.
There is one as disclosed in the drawing of No. 3811.
Further, as a plurality of independent ink passages, there is one which is disclosed in the drawing of Japanese Utility Model Application Laid-Open No. 57-136778.

[Problems to be Solved by the Invention]

The ink passage in the vicinity of the center of the ball receiving seat is apparently blocked by the ball held in the ball holding chamber, and the ball is directly blocked. The ink supplied to the opening of the ball holding chamber is ink that passes through the gap formed by the outermost ball of the ball holding chamber and the side wall of the ball holding chamber. .

The amount of ink supplied to the gap formed directly by the ball and the side wall of the ball holding chamber is equal to the opening area of the ink passage opening which is not blocked by the ball. To be affected.

When the ball rotates during writing, the ball receiving seat that comes into contact with the ball is gradually worn away. This is the so-called ball sinking phenomenon. When the ball sinking phenomenon occurs, the area of the ink passage opening blocked by the ball gradually increases, and the opening area of the ink passage opening described above gradually decreases. Therefore,
The amount of ink discharged decreases as the ball sinks. In the conventional ink passage, the reduction of the opening area of the ink passage opening tends to proceed in proportion to the wear of the ball receiving seat portion, and as the ball sinking phenomenon progresses, the handwriting is blurred during writing. The phenomenon occurred.

Further, due to the rotation of the ball, stress is likely to be concentrated at the edge portion of the ink passage opening portion, especially at the corner portion, and the material of this portion is deformed in the direction of blocking a part of the ink passage. However, there has been a problem that the fading phenomenon is likely to occur early in the process because it promotes a decrease in the ink discharge amount over time with use.

[0008]

The inventors of the present invention have earnestly studied the occurrence of the blurring phenomenon of the ball-pen as described above, and as a result, the shape of the ink passage is large in the occurrence of the blurring phenomenon. It was found that they contributed. That is, according to the present invention, a ball holding chamber for holding a ball as a writing member so as to partially project from the opening by forming an opening having a diameter smaller than the diameter of the ball at the tip. BO
In a ball-pen tip formed by opening an ink passage radially formed radially outward from the vicinity of the center of the ball-receiving seat, to the ball-receiving seat of the ink passage. The opening of the
Has a width length of 12% to 35% with respect to the diameter of the ball, and expands at an angle of 20 ° to 60 ° from the minimum width portion toward the radial outside of the ball receiving seat portion. The gist of the present invention is a ballpoint pen tip.

[0009]

The edge portion of the opening of the ink passage is susceptible to deformation due to stress concentration due to the rotation of the ball, but the deformed material grows in the direction of closing the ink passage due to the force. That is, in the edge portion of the opening portion of the ink passage, which corresponds to the corner portion, the deformed portions of the mutually grown materials are likely to close a part of the ink passage. Therefore, if this corner portion has an acute angle, a part of the ink passage is more likely to be blocked, and it is necessary that the minimum width portion of the ink passage has a certain width.

Further, since the ink passage is expanded outward from the minimum width portion at a certain large angle, the ink passage opening is blocked by the ball as the ball sinking phenomenon progresses. The reduction rate of the opening area of the part becomes low. In other words, even if the ink passage is slightly blocked by the ball, a large amount of ink is guaranteed in the outermost portion of the ink passage, so that the ink ejection is reduced depending on the progress of the ball sinking phenomenon. The rate is low, and the fading phenomenon of handwriting in the early stage is less likely to occur.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a main portion of a ball pen tip A according to the present invention, in which the diameter of the ball holding chamber 1 is smaller than the diameter of the ball 3 by caulking the tip 2 The opening 4 is formed, and the ball 3 as a writing member is held so as to partially project from the opening 4.

The ball receiving seat 5 of the ball holding chamber 1
After installing the ball 3 in the ball holding chamber 1 and caulking the tip portion 2, the ball 3 is pressed toward the ball receiving seat 5 (downward in the drawing), -The surface shape of the ball 3 is transferred to the vicinity of the center of the ball receiving seat 5. That is, when the ink having a lubricating effect is obtained by bringing the ball 3 and the ball receiving seat portion 5 into a state close to surface contact. This gives a smooth writing feel.

Further, as shown in FIG. 2 which is a sectional view taken along the line I--I of FIG. 1 (the ball 3 is omitted for convenience of explanation), the ball receiving seat portion 5 of the ball pen tip A is shown. In the
The ink passage 6 for supplying ink to the holding chamber 1 is opened. The ink passage 6 includes a central hole 6a having a relatively weak capillary force and a radial groove 6b communicating with the central hole 6a and having a relatively strong capillary force.

Here, in the ink passage 6, the width x of the minimum width portion 6c formed by the opening portion opening to the ball receiving seat 5 is 12% to the diameter of the ball 3. 35%
The radial groove 6b is formed to have a length 2 from the minimum width portion 6c toward the outside in the radial direction of the ball receiving seat portion 5.
It expands at an angle of 0 ° to 60 °. Note that this spread angle is hereinafter referred to as y.

Another example is shown in FIG. 3 and FIG. 4 which is a sectional view taken along line II-II of FIG. 3 (the ball 3 is omitted for convenience of description). Parts that are basically the same as those in FIG. 1 are assigned the same reference numerals as those in FIG. By forming the tip portion 2 of the ball holding chamber 1 as a portion having a diameter smaller than the diameter of the ball 2, the ball 3 serving as a writing member is held,
The point that it partially projects from the opening 4 is the same as that shown in FIG.

This example differs from the example shown in FIGS. 1 and 2 in that in the ink passage 6 shown in FIG. 1, a plurality of radial grooves 6b communicate with the central hole 6a, and one ink passage is provided as a whole. 6
While it was formed as shown in FIG.
In the ink passage of this example, a plurality of ink passages are formed at point-symmetrical positions with the center of the ball receiving seat portion as a target point without forming a central hole in the central portion of the ball receiving seat portion 5. This is a point.

In the ink passage 6, a minimum width portion 6c having a width x is formed at a position closest to the center of the ball receiving seat portion 5, and further outward from the center of the ball receiving seat portion 5. It is formed into a fan shape by expanding at an expanding angle y. BO
The center portion of the le receiving seat portion 5 has a substantially circular island portion 5a. The part of the ball receiving seat 5 that contacts the ball 3 is formed outside the island 5a without being formed in the front punch island 5a, and does not contact the ball 3 on the island 5a. Recess 5b
Has been formed. By doing so, ink can be supplied to the recess 5b even in the vicinity of the center of the ball receiving seat 5 which is apparently blocked by the ball 3 of the ink passage 6. In other words, even if a part of the ink passage 6 is apparently blocked, the sufficient ink supply in the vicinity of the ball 3 is secured and the blurring phenomenon of the handwriting is further suppressed.

The ink passage having such a shape has a large contact area with the ball 3 in the ball receiving seat 5, and the contact of the ball receiving seat 5 with the ball 3 is large. Even if a part is worn, the amount of ball sinking with respect to the amount of wear is small.
Therefore, the phenomenon that the ink passage is blocked by the ball 3 due to the ball sinking phenomenon is relatively unlikely to occur. Therefore, since the present example is advantageous in terms of molding and abrasion resistance, it can be said that it is suitable when used as a ball-pen tip made of synthetic resin.

Besides the above, various modifications can be made without departing from the gist of the present invention. As for the material of the ball pen tip, in addition to metals such as stainless steel, nickel silver, brass and aluminum, polyoxymethylene, polybutylene terephthalate, polycarbonate, polyethylene terephthalate, polyether ether ketone. Examples include injection-molded products of synthetic resin having excellent wear resistance. In particular, with respect to the one formed with the ink passage as shown in FIG. 3 described above, a synthetic resin having a complicated structure can be easily manufactured. Further, in the example shown in FIGS. 1 and 2,
FIG. 3 shows a case where three radial grooves 6b are formed.
Also, in the example shown in FIG. 4, three independent ink passages 6 are shown, but the number thereof is not limited to this. Further, the ink to be used can be variously used in consideration of the reactivity with the material, and is not limited to the ink viscosity. In particular, the example shown in FIGS. 1 and 2 has a viscosity of 1
It is advantageous because it is possible to guarantee a large amount of ink ejection even for high-viscosity ink having a viscosity of 500 centipoise or more.

[0020]

In the ball-point pen tip shown in FIG. 1, the width length x and the expansion angle y that expands outward from the minimum width portion 6c in the radial direction of the ball receiving seat portion 5 are specifically described. As a typical value, a ball-pen tip with a ball diameter of 0.8 mm is made of a ferrite diameter stainless steel material, and a pipe filled with ink (water-based ink having metal fine particles as a coloring material, viscosity 20000 centipoise) is connected, and The rate of occurrence of fading and the rate of decrease in ink discharge were measured by a writing test. The results are shown in Table 1, Table 2 and Table 3. In addition, the rate of occurrence of blurring is 7 cm / sec., A spiral writing tester that writes a circle with a diameter of 30 mm at a writing load of 100 g and a writing angle of 70 degrees (WEITING TE manufactured by Seiki Kogyo Kenkyusho).
800 in STAR MODEL TS-4C-10)
m Writing, measuring the blurring distance in the handwriting (the distance of the portion where the handwriting line is extremely thin or the handwriting line is broken), 800
The value is divided by m and multiplied by 100. Further, the reduction rate of ink discharge is a value calculated by the formula; (ink discharge amount of 600 m to 800 m writing / ink discharge amount of 0 m to 200 m writing) × 100. Where x = 0.30 mm y =
From 0 ° to 50 °, the load applied to the cutting blade for forming the ink passage is too large to process, and y = 70 ° x = 0.05 mm to 0.1.
Up to 0 mm, it is impossible to process due to the problem of durability of the cutting blade, and further, y ≧ 60 ° or more with x = 0.30 mm and x ≧ 0.15 mm with y = 70 ° are the reasons for both the above and It cannot be processed by.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

As described above, according to the present invention, by forming an opening portion having a diameter smaller than the diameter of the ball at the tip portion, the ball as a writing member holds the ball partially protruding from the opening portion. In a ball pen tip formed by opening an ink passage radially formed radially outward from the vicinity of the center of the ball receiving seat portion of the holding chamber, a ball pen of the ink passage is formed. -The opening to the ball receiving seat has a minimum width portion having a width length of 12% to 35% with respect to the diameter of the ball, and the opening of the ball receiving seat portion from the minimum width portion. Since it seems to spread outward at an angle of 20 ° to 60 ° toward the outside in the radial direction, the reduction rate of ink discharge is low with respect to the progress of the ball sinking phenomenon, and the handwriting blurring phenomenon at an early stage is minimized. It suppresses.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an example of the present invention.

FIG. 2 is a top view of the example of FIG.

FIG. 3 is a cross-sectional view of a main part showing another example.

FIG. 4 is a top view of the example of FIG.

[Explanation of symbols]

 A ball pen tip 1 ball holding chamber 2 tip 3 ball 4 opening 5 ball receiving seat 5a island 5b recess 6 ink passage 6a center hole 6b radial groove 6c minimum width x width y Expansion angle

Claims (1)

[Claims] 1. A ball in a ball-holding chamber for holding a ball as a writing member so as to partially project from the opening by forming an opening having a diameter smaller than the diameter of the ball at the tip. In a ball-pen tip formed by opening an ink passage radially formed radially outward from the vicinity of the center of the ball receiving seat portion, the ball receiving seat portion of the ink passage is formed. Has a minimum width portion having a width length of 12% to 35% with respect to the diameter of the ball, and extends outward from the minimum width portion in the radial direction of the ball receiving seat portion. Ball pen tip characterized in that it is spread at an angle of 20 ° to 60 °.