JPH0966692A - Ball point pen tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ink ball point pen of superior ink introducing properties to be manufactured easily and optimum for writing small characters. SOLUTION: A plurality of inward protrusions 31 are formed in the vicinity of the end of a metal cylindrical fine tube 3 by press deforming. The front faces of the inward protrusions 31 are used as ball seats, and a ball 2 is disposed revolvably on the end of the fine tube 3. An ink leading refill 4 is inserted loosely in the fine tube 3, and the end of the ink leading refill 4 is brought into contact with the rear faces of the inward protrusions 31. A cylindrical ink flow clearance 7 is formed between the inner face of the fine tube 3 and the outer face of the ink leading refill 4. The ink leading refill 4 is a metal bar having the outer diameter E smaller than the inner diameter D of the fine tube 3 by 0.04mm-0.24mm.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a ballpoint pen tip. More specifically, the present invention relates to a pipe-type ballpoint pen tip suitable for a relatively low-viscosity water-based ink.

[0002]

2. Description of the Related Art In a conventional ball-point pen tip of this type, the purpose is to prevent the ink on the back of the ball from dropping back when the pen tip is left facing upward or when a shock is applied during transportation or carrying. In Japanese Utility Model Publication No. 3-56385, for example, "a chip for rotatably mounting a ball at the tip and for arranging an ink guiding member (corresponding to the ink guiding core of the present invention) inside, respectively. There is a plurality of inward projections formed by pressing deformation from the outside as a ball seat, in a metal pipe tip for a ballpoint pen using water-based ink, by forming a crack during the pressing deformation, A metal pipe tip for a ballpoint pen, characterized in that a groove is formed on the inner wall surface of the inward protruding portion. " Further, in the examples of the above-mentioned publications, as an example of the ink guiding member, "ink bundles, resin sintered bodies, foamed bodies, extruded bodies, or ink flow passages on inner and outer walls made of metal rods or ceramic rods, etc. Is appropriately formed. "

[0003]

The conventional ball-point pen tip generally employs a ball having an outer diameter of 0.5 mm to 0.7 mm, has a wide handwriting width, and is suitable for writing on details such as a notebook. Not suitable. Therefore, in order to obtain a ballpoint pen tip for fine characters having a small handwriting width, a ball having a smaller outer diameter, for example, an outer diameter of 0.3 mm or 0.4 mm
If such balls are used, it is necessary to prepare thin metal pipes and ink guide cores correspondingly.

When the ink guide core is made of synthetic resin, it is difficult to form an ink guide core having a small outer diameter (specifically, one having a diameter smaller than 0.4 mm), and at the same time, it is lightweight. It is not easy to handle because it tends to be electrostatically attracted by friction between the induction cores. Furthermore, when the rear end of the ink guide core is connected to a fibrous body or a porous body in a pierced state, in the case of a small diameter ink guide core made of synthetic resin,
The strength is insufficient and the material is easily bent, and there is a risk that it will not normally stick into a fibrous body or a porous body.

Further, in the case of a metal ink induction core, the shape of the end portion of the ink induction core varies during manufacture. Therefore, the ink guide core does not make proper contact with the inward protrusions, and the space formed between the tip of the ink guide core and the back surface of the ball is enlarged, thereby deteriorating the ink derivability and breaking the handwriting. May occur, or the tip of the ink guide core may come into contact with the back surface of the ball, which hinders smooth rotation of the ball. In addition, as the outer diameter of the metallic ink guide core becomes smaller, it becomes more difficult in manufacturing to provide grooves or holes for guiding ink in the longitudinal direction on the inner and outer surfaces.

The present invention solves the above-mentioned conventional problems, and is intended to provide a ball-point pen tip for water-based ink which is easy to manufacture and at the same time excellent in ink derivation, and which is most suitable for writing fine letters. is there.

[0007]

SUMMARY OF THE INVENTION The present invention provides a plurality of inward projections 31 by pressing deformation in the vicinity of the tip of a metal cylindrical thin tube 3, and uses the front surface of the inward projections 31 as a ball receiving seat. The ball 2 is rotatably arranged at the tip of the thin tube 3, and the ink guiding core 4 is loosely inserted in the thin tube 3, and the tip of the ink guiding core 4 is set at the inner projection 31.
The inner surface of the thin tube 3 and the ink guide core 4 are brought into contact with the rear surface.
A ball-point pen tip having a cylindrical ink circulation gap 7 formed between the ink guide core 4 and the outer surface of the thin tube 3 having an outer diameter E smaller by 0.04 mm to 0.24 mm. It is a requirement that it be a metal rod-shaped body.

Ink guide core (outer diameter E) The ink guide core 4 is a rod-shaped body made of metal such as stainless steel, aluminum, or brass, and its cross-sectional shape is circular, elliptical, regular polygonal (for example, triangular). , Square, hexagon) and the like. Ink induction core 4 of the present invention
The outer diameter dimension E of is the diameter when the cross-sectional shape is circular,
An irregular shape such as an ellipse or a regular polygon is defined by the maximum value of the outer diameter. The outer diameter E of the ink guide core 4 is preferably set to be smaller than the inner diameter D of the thin tube 3 by 0.04 mm to 0.24 mm (preferably 0.1 mm to 0.2 mm). When the difference between the inner diameter D of the thin tube and the outer diameter E of the ink guide core (that is, D minus E) is smaller than 0.04 mm,
The ink flow gap 7 formed between the inner surface of the thin tube 3 and the outer surface of the ink guide core 4 becomes too small, which hinders smooth ink extraction and causes handwriting interruption. On the other hand, when the difference between the inner diameter D of the thin tube and the outer diameter E of the ink guide core is larger than 0.24 mm, the ink circulation gap 7 becomes excessively large and the ink holding force becomes weak. The ink may be dragged back, or the ink may excessively flow out from the tip of the pen when writing. In particular, the difference between the inner diameter D of the thin tube and the outer diameter E of the ink guide core 4 is 0.1 mm to
When it is in the range of 0.2 mm, the ink flow gap 7 has a reliable ink derivation without discontinuity of handwriting and a stable ink holding force without drop haddock.

(Tapered portion) The ink guide core 4 has a tapered portion 41 (for example, a convex curved surface, a concave curved surface or a tapered surface) in a circumferential shape at its tip, and the tapered shaped portion 41 is an inward projection. It is preferable to contact the rear surface of 31.

(Surface Treatment) The ink guiding core 4 may have an ink guiding path such as a longitudinal groove or hole in its outer peripheral surface or inside, or may not have it at all.
In the ink guiding core 4 in which the ink guiding path does not exist, a surfactant is applied to the surface thereof in order to improve the wettability of the ink, or fine irregularities are formed by acid corrosion treatment or sand blasting, that is, It is preferable to apply a roughening treatment. Examples of the corrosion treatment include a method of corroding with an acid such as hydrochloric acid, sulfuric acid or nitric acid to form fine irregularities on the surface thereof at the metal crystal grain level.

(Ink Impregnated Body) The ink guide core 4 is
The rear end is preferably connected to the ink impregnated body 5 in a pierced state. Examples of the ink impregnated body 5 include a resin processed body of a fiber bundle, a synthetic resin porous body having open cells, and the like.

Ink distribution gap The ink distribution gap 7 formed between the inner surface of the thin tube 3 and the outer surface of the ink guide core 4 is preferably cylindrical. The ink guide core 4 is 0.04 mm to 0.2 mm larger than the inner diameter D of the thin tube 3.
By having an outer diameter E smaller by 4 mm, the ink flow gap 7 has a gap size F (more accurately, the minimum value of the gap size on one side in the radial direction) of 0.02 mm to 0.12 m.
It is set in the range of m (preferably 0.05 mm to 0.1 mm). In particular, the gap dimension F is 0.05 mm
In the range of 0.1 mm, there is no risk of ink dropback during upward storage of the pen tip, and moreover, smooth derivation of ink during writing is possible.

The thin tube 3 is preferably a straight cylindrical shape having a substantially uniform wall thickness, that is, a substantially uniform inner and outer diameter. The material is austenitic stainless steel (for example, SUS304,
SUS305, SUS321). further,
The inner diameter D of the thin tube 3 is 0.25 in order to obtain a narrow handwriting.
The range of mm to 0.5 mm is effective, and the diameter is set to be slightly larger than the outer diameter of the ball 2. Specifically, the thin tube 3
Inner diameter D is 0.01 mm to 0.05 m greater than ball outer diameter
It is set to about m, so that a smooth rotation of the ball 2 with less rattling can be obtained during writing.

Ball The outer diameter of the ball 2 is slightly smaller than the inner diameter D of the thin tube 3 (specifically, 0.01 mm to 0.
(Small about 05 mm), specifically 0.2 mm to 0.
It is in the range of 45 mm.

Inner protrusions It is preferable that a plurality (specifically, three or four) of the inner protrusions 31 are provided on the outer peripheral surface of the thin tube 3 at equal intervals in a circumferential shape. Between the adjacent inward projections 31 is a capillary gap 31a having a size similar to the gap size F of the ink flow gap 7.
(Gap dimension G is 0.02 mm to 0.12 mm).

[0016]

The ink is supplied from the rear to the back surface of the ball 2 by the ink flow gap 7 and the capillary gap 31a between the adjacent inner protrusions 31. In particular, the ballpoint pen tip 1 of the present invention
Since the ink guide core 4 has an outer diameter E smaller than the inner diameter D of the thin tube 3 by 0.04 mm to 0.24 mm, the ink flow gap 7 is set so that there is no risk of ink dropback or dripping. The ink can be derived smoothly without interruption. Further, since the ink guide core 4 is a metal rod-shaped body, the ink guide core 4 having a small diameter can be easily manufactured and the ink guide core 4 can be easily handled. Improve the assembly work to 1.

At the tip of the ink guide core 4, a tapered portion 41 is formed.
Is provided in a circumferential shape, the tip of the ink guide core 4 is stabilized in a tapered shape without variation. Further, the tapered portion 41 (for example, a curved surface or a tapered surface) is provided with an inward projection 31.
The ink guide core 4 is surely brought into contact with the rear surface.
Can be made closer to the back surface of the ball 2, and the space between the tip of the ink guide core 4 and the back surface of the ball 2 can be set to a relatively small and stable size without variation. Thereby, the ball 2
Improves ink retention on the back surface and prevents breaks in handwriting during writing.

By providing fine irregularities on the surface of the ink guiding core 4, the surface of the ink guiding core 4 is small even though the ink guiding core 4 is a thin metal rod for which it is difficult to form an ink guiding path. Ink wettability can be improved, and as a result, stable ink derivation performance can be satisfied.

When the rear end of the ink guiding core 4 is connected to the ink impregnated body 5 in a piercing manner, the ink guiding core 4
Is a metal rod-shaped body, has sufficient strength against bending and is reliably connected to the ink impregnated body 5.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 (FIGS. 1 to 4) FIG. 1 is a vertical sectional view of a first embodiment of a ball-point pen tip 1 of the present invention. The ball-point pen tip 1 is mainly composed of a metal thin tube 3 that rotatably holds a ball 2 at its tip, and the thin tube 3
It comprises a metal rod-shaped ink guide core 4 loosely inserted therein, and a holder 6 made of synthetic resin in which the thin tube 3 is held in the front part and an ink impregnated body 5 is inserted in the rear part.

The holder 6 is obtained by injection molding a synthetic resin such as polyacetal, polypropylene or polyethylene. Further, the holder 6 is a tubular body, and has a thin tube mounting hole 61 in the front part, an impregnating body mounting hole 62 in the rear part, and a communication hole 63 between the two mounting holes 61, 62. It is provided. The rear portion of the thin tube 3 is press-fitted and fixed into the thin tube mounting hole 61, and the rod-shaped ink impregnated body 5 (for example, a resin processed body of polyester fiber) front portion is inserted into the impregnating body mounting hole 62. The holder 6 is heat-sealed to the outer peripheral surface of the ink impregnated body 5 at its rear end.

An ink guide core 4 is loosely inserted in the thin tube 3. The tip of the ink guide core 4 is an inward projection 3
The back end of the ink impregnated body 1 is abutted against the rear surface of the ink impregnated body 1, and the rear end is pierced by the tip of the ink impregnated body 5, that is, is sandwiched and fixed by the inward projection 31 and the ink impregnated body 5. Then, the outer surface of the ink guide core 4, the inner surface of the thin tube 3, and the communication hole 63.
A cylindrical ink flow gap 7 having a capillary force is formed between the inner surface and the inner surface.

A support cylinder 64 made of metal (for example, brass) is press-fitted and fixed to the outer peripheral surface of the front portion of the holder 6. The support tube 64 supports the outer peripheral surface of the thin tube 3 during writing and prevents the thin tube 3 from wobbling and bending.

Next, the tip of the ballpoint pen tip 1 of FIG. 1 will be described in more detail with reference to FIGS. FIG.
1 is an enlarged view of part A of FIG. 1, FIG. 3 is a sectional view taken along line BB of FIG. 2, and FIG. 4 is a sectional view taken along line CC of FIG.

As the thin tube 3, the outer diameter: 0.5 mm, the inner diameter D: 0.32 mm, the outer diameter: 0.65 mm, the inner diameter D:
0.42mm stainless steel (specifically SUS30
Two types of cylinders of 4) are prepared. In the vicinity of the tip of the thin tube 3, three inward projections 31 are provided in a circumferential shape at equal intervals in a conical surface shape or a spherical shape by pressing and deforming from the outside to the inside. An inwardly deformed conical surface-shaped tip edge portion 32 is provided. The ball 2 is attached to the tip of the thin tube 3 by the inward projection 31 and the tip edge portion 32.
Is rotatably held. The ball 2 has two kinds of outer diameters made of cemented carbide (specifically, an outer diameter of 0.3 mm corresponding to a thin tube 3 having an inner diameter of 0.32 mm and 0 corresponding to a thin tube 3 having an inner diameter of 0.42 mm. Those having an outer diameter of 0.4 mm) are prepared. Further, a capillary gap 31a (the minimum value of the gap dimension G is 0.05 m) is provided between each of the inward projections 31.
m-about 0.1 mm) is provided. Also, the inward projection 31
The diameters H of the virtual inscribed circles contacting the vertices of each are 0.1
3 mm (corresponding to ball outer diameter 0.3 mm), 0.15 mm
(Corresponding to a ball outer diameter of 0.4 mm), which is smaller than the outer diameter E of the ink guide core 4 and the outer diameter of the ball 2.

The outer diameter E of the ink guide core 4 is 0.2 m.
made of stainless steel having a circular cross section of m and 0.3 mm (specifically, SUS having a Vickers hardness of 150 to 500)
304) straight rod-shaped body (or linear body).
The ink guide core 4 having an outer diameter E of 0.2 mm has an inner diameter of 0.
Compatible with 32 mm thin tubes and balls with an outer diameter of 0.3 mm,
The ink guide core 4 having an outer diameter E of 0.3 mm has an inner diameter of 0.
It corresponds to a 42 mm thin tube and a ball with an outer diameter of 0.4 mm. The ink guide core 4 is cut into an appropriate size and then barrel-polished to form an R curved surface (convex curved surface) in an annular shape at both ends thereof. As a concrete method of the barrel polishing, for example, in a unit of 1000 to 10000 pieces, a spherical grindstone having an outer diameter of 1 mm to 10 mm and water are used to form 0.5 to
A method of performing polishing treatment for 2 hours can be mentioned. By the barrel polishing, a large amount of the ink guide core 4 can be efficiently processed in a short time. The ink guide core 4 does not have an ink lead-out path formed by grooves or holes in the longitudinal direction on its inner and outer surfaces, but its surface is corroded by acid (specifically, the ink guide core 4 is % Aqueous solution of hydrochloric acid for 5 hours) to form fine irregularities having a metal crystal grain size, and the ink wettability sufficient to lead out the ink is imparted.

Since the tip of the ink guide core 4 is in contact with the rear surface of the inward projection 31 at its tapered portion 41,
The gap in the longitudinal direction between the back surface of the ball 2 and the tip of the ink guide core can be set to be relatively small, and the ink holding force by the capillary tube on the back surface of the ball 2 is improved. Moreover, since the tip of the ink guide core 4 is not in contact with the back surface of the ball 2, it does not hinder the smooth rotation of the ball.

Application Example 1 (FIG. 5) FIG. 5 shows an application example of the ball-point pen tip 1 of FIG. This is the ball-point pen tip 1 of the first embodiment (FIG. 1) (that is, the ball-point pen tip 1 consisting of the ball 2, the thin tube 3, the ink guide core 4, the ink impregnation body 5, the holder 6, and the support cylinder 64). A direct liquid type composed of a fixed ink storage member 9 and a shaft cylinder 8 having the ink storage member 9 mounted on the front part and an ink tank 81 for storing raw ink (low viscosity water-based ink) formed on the rear part. It is an aqueous ballpoint pen.

The ink storage member 9 is the ink tank 8
The overflow ink according to the pressure change in 1 is temporarily held, and a plurality of comb teeth 91 that form a large number of retaining grooves 92 on the peripheral surface, and the comb teeth 91 are provided so as to penetrate in the axial direction. Slit 93 communicating with the retaining groove 92, and the slit 93
Air exchange concave groove 94 disposed on the comb teeth 91 at the opposite position
And the central hole 95 penetrating the shaft center are integrally formed of synthetic resin (for example, ABS resin).

Into the central hole 95, an ink supply core 96 (specifically made of a synthetic resin extruded body) having an axial ink lead-out passage having a capillary force on the outer peripheral surface or the inner peripheral surface is inserted. It is worn. The tip of the ink supply core 96 is sharpened by grinding and connected to the rear end of the ink impregnated body 5 in a pierced state.

Application Example 2 (FIG. 6) FIG. 6 shows an application example of the ball-point pen tip 1 of FIG. This is a so-called batting type water-based ink ballpoint pen in which the ballpoint pen tip 1 of the first embodiment (FIG. 1) is attached to the tip of the barrel 8. An ink occlusion body 82 (filling pad) made of a fiber processed body or a porous body is housed and arranged in the shaft cylinder 8. The ink occlusion body 82 is impregnated with a low-viscosity water-based ink inside, and a contact rib 83 arranged on the inner wall of the barrel 8 and a tail plug 84 fitted in the rear end opening of the barrel 8. It is clamped and fixed by. In addition, the ink occlusion body 82
The rear end of the rod-shaped ink impregnated body 5 is immersively connected to the tip of the in a piercing state.

Embodiment 2 (FIG. 7) FIG. 7 shows another example of the shape of the end portion of the ink guide core 4.
An annular taper surface (conical surface) is provided at the tip of the ink guide core 4 by cutting, grinding, plastic working, or the like to form a tapered portion 41. The tip of the ink guide core 4 is in contact with the rear surface of the inner protrusion 31, but is not in contact with the back surface of the ball 2. Other configurations and operational effects are the same as those in FIG.

Embodiment 3 (FIG. 8) FIG. 8 shows another example of the shape of the end portion of the ink guide core 4.
At the tip of the ink guide core 4, cutting, grinding, barrel polishing,
Alternatively, a semi-spherical surface including an annular R curved surface is formed by plastic working or the like to form the tapered shape portion 41. The tip of the ink guide core 4 is in contact with the rear surface of the inner protrusion 31, but is not in contact with the back surface of the ball 2. Other configurations and operational effects are the same as those in FIG.

[0035]

The ballpoint pen tip of the present invention has the features of claim 1.
(That is, the ink induction core is 0.0
Since it is a metal rod having an outer diameter as small as 4 mm to 0.24 mm), it is easy to manufacture and assemble, and it has excellent ink derivability, which is suitable for writing fine letters.

The ink guiding core according to the second aspect of the invention (that is, the tapered portion is circumferentially provided at the tip of the ink guiding core, and the tapered portion is brought into contact with the rear surface of the inward projection). Stabilizes the shape of the tip of the ink without variation, and as a result, improves the ink holding power on the back of the ball and prevents breaks in handwriting during writing.

With the structure of claim 3 (that is, by providing fine irregularities on the surface of the ink guide core), the ink wettability of the ink guide core can be improved, and as a result, stable ink derivation performance can be satisfied.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

3 is a cross-sectional view taken along the line BB of FIG.

4 is a cross-sectional view taken along the line CC of FIG.

FIG. 5 is a vertical cross-sectional view showing an application example of the first embodiment of the present invention.

FIG. 6 is a vertical sectional view showing an application example of the first embodiment of the present invention.

FIG. 7 is an enlarged cross-sectional view showing another example of the ink guide core end portion applied to the present invention.

FIG. 8 is an enlarged cross-sectional view showing another example of the ink guide core end portion applied to the present invention.

[Explanation of symbols]

 1 Ballpoint Pen Tip 2 Ball 3 Capillary Tube 31 Inner Protrusion 31a Capillary Gap 32 Tip Edge Part 4 Ink Lead Core 41 Tapered Shaped Part 5 Ink Impregnation Body 6 Holder 61 Capacitor Mounting Hole 62 Impregnation Body Mounting Hole 63 Communication Hole 64 Support Tube 7 Ink distribution gap 8 Shaft cylinder 81 Ink tank 82 Ink occlusion body 83 Abutment rib 84 Tail plug 9 Ink storage member 91 Comb teeth 92 Storage groove 93 Slit 94 Air exchange recessed groove 95 Center hole 96 Ink supply core D Inner diameter dimension E Outer diameter dimension of ink induction core F Gap dimension of ink flow gap G Gap dimension of capillary gap H Diameter of virtual inscribed circle in contact with apex of inner protrusion

Claims (4)

[Claims] 1. A thin tube (3) having a plurality of inward projections (31) provided near the tip of a metal cylindrical thin tube (3) by pressing and deforming, and the front surface of the inward projections (31) serving as a ball receiving seat. ) A ball (2) is rotatably arranged at the tip, and an ink guide core (4) is loosely inserted in the thin tube (3), and the tip of the ink guide core (4) is attached to the rear surface of the inward projection (31). A ball-point pen tip, which is formed by contacting the inner surface of the thin tube (3) and the outer surface of the ink guide core (4) to form a cylindrical ink circulation gap (7). )But,
0.04 mm to 0.2 from the inner diameter (D) of the thin tube (3)
A ball-point pen tip, which is a metal rod-shaped body having an outer diameter (E) smaller by 4 mm. 2. A taper-shaped portion (41) is circumferentially provided at the tip of the ink guide core (4), and the taper-shaped portion (41) is brought into contact with the rear surface of the inward projection (31). 1 ballpoint pen tip. 3. The ball-point pen tip according to claim 2, wherein fine irregularities are provided on the surface of the ink guide core (4). 4. The ball-point pen tip according to claim 1, wherein the rear end of the ink guide core (4) is connected to the ink impregnated body (5) in a pierced state.