JP7269153B2 - ballpoint pen - Google Patents

Description

The present invention relates to ballpoint pens.

In this type of ballpoint pen, Patent Document 1 describes a water-based ballpoint pen tip that is injection-molded by filling a thermoplastic synthetic resin with carbon fibers. Further, Patent Document 2 describes a water-based ball-point pen tip made of a synthetic resin mixed with carbon fiber or glass fiber.

Japanese Utility Model Laid-Open No. 59-43184 Japanese Utility Model Laid-Open No. 60-96077

The ball-point pen tips of Patent Documents 1 and 2 tend to damage the mold when the tip body is obtained by injection molding, and there is a risk that proper molding cannot be maintained for a long period of time.

The present invention is intended to solve the above-mentioned conventional problems. The strength of the tip body is improved, and the damage to the mold when the tip body is obtained by injection molding is suppressed, so that the tip body can be properly molded over a long period of time. To provide a ball-point pen capable of maintaining a water-based ink and improving the wettability or liquid retention of the ink in the tip body when water-based ink is employed. In the present invention, "front" refers to the tip side of the tip of the ballpoint pen, and "rear" refers to the opposite side.

A ball-point pen 1 according to the present invention comprises a ball-point pen tip 2 in which a ball 4 is rotatably held at the front end of a tip body 3 made of synthetic resin. It is characterized by containing fibers.

In the ball-point pen 1 constructed in this manner, the strength of the tip body 3 is improved, damage to the mold when the tip body 3 is obtained by injection molding is suppressed, and proper molding of the tip body 3 can be maintained for a long period of time. It is preferable to employ cellulose nanofibers having an average fiber diameter in the range of 1 to 1000 nm (nanometers).

Further, in the ball-point pen 1 according to the present invention described above, it is desirable that the tip body 3 contains 0.1 to 10% by mass of cellulose nanofibers in the total amount of the synthetic resin. According to this, the strength of the tip body 3 is improved, the balls are prevented from dropping out of the tip body 3, the abrasion of the ball receiving seat is suppressed, and the proper molding of the tip body 3 can be maintained. If less than 0.1% of the cellulose nanofiber is contained in the total amount of the synthetic resin of the tip body 3, there is a fear that the effect of improving the strength of the tip body 3 against ball dropout and wear of the ball receiving seat may not be obtained. If the total amount of the synthetic resin of the chip body 3 exceeds 10%, it may become difficult to form the chip body 3 properly.

Further, in the ball-point pen 1 according to the present invention described above, it is desirable that the synthetic resin of the tip body 3 containing the cellulose nanofibers is polyacetal. According to this, it is possible to maintain proper molding of the tip body 3 for a long period of time, and obtain smooth rotation of the ball with reduced writing resistance.

Moreover, it is preferable that the ball-point pen 1 according to the present invention is configured so that water-based ink is accommodated therein and the water-based ink can be discharged from the front end of the ball-point pen tip 2 . According to this, the wettability or liquid holding property of the ink in the tip body 3 is improved, and a smooth writing feeling (reduction of writing resistance) accompanying the smooth outflow of the ink during writing can be obtained. To obtain a water-based ball-point pen capable of suppressing impossibility of writing due to ink dropping (dropback) in the ball-point pen tip 2 when the tip of the pen is turned upward.

Further, in the above-described ballpoint pen 1 according to the present invention, the barrel 5 having the ballpoint pen tip 2 at the front end, the ink container 6 disposed inside the barrel 5 and impregnated with water-based ink and held therein, and the front end is disposed within the ball-point pen tip 2 and has a rear end connected to the front end of the ink reservoir 6 . According to this, the wettability or liquid holding property of the ink in the tip body 3 is improved, and a smooth writing feeling (reduction of writing resistance) accompanying the smooth outflow of the ink during writing can be obtained. To obtain a water-based ball-point pen capable of suppressing impossibility of writing due to ink dropping (dropback) in the ball-point pen tip 2 when the tip of the pen is turned upward.

ADVANTAGE OF THE INVENTION The ball-point pen of the present invention improves the strength of the tip body, suppresses damage to the mold when the tip body is obtained by injection molding, and can maintain proper molding of the tip body for a long period of time.

1 is a vertical cross-sectional view of a main part of a ballpoint pen according to an embodiment of the present invention; FIG. FIG. 2 is an enlarged sectional view taken along line AA of FIG. 1; 2 is an enlarged longitudinal sectional view of the ball-point pen tip of FIG. 1; FIG. 4 is a cross-sectional view taken along line BB of FIG. 3; FIG. 4 is a cross-sectional view taken along line CC of FIG. 3; FIG. 4 is a perspective view of the ballpoint pen tip of FIG. 3; FIG.

An embodiment of the present invention will be described based on the drawings. (See Figures 1 to 6)
The ball-point pen 1 of the present embodiment includes a ball-point pen tip 2, a barrel 5 having a front end hole 51 to which the ball-point pen tip 2 is attached, and an ink storage portion 6 made of a fiber processed material accommodated in the barrel 5. (ink occluding body), an ink guide member 7 made of a processed fiber and connected to the front end of the ink containing portion 6, and a tail plug (not shown) attached to the rear end opening of the barrel 5. Prepare.

The ink containing portion 6 is impregnated with water-based ink (ink containing water as a main solvent and a dye or pigment as a coloring agent). The ink guide member 7 supplies ink from the ink containing portion 6 to the ball-point pen tip 2 . In addition to this, the ink containing portion 6 may be configured to store ink directly. Alternatively, the ink may be directly stored in the ink containing portion 6 and the ink may flow directly through the ball-point pen tip 2 without passing through the ink guide member 7 .

- Mandrel The mandrel 5 is a cylindrical body, and is obtained by molding a synthetic resin (for example, polypropylene).
A front end portion of the barrel 5 is tapered, and a front end hole 51 is axially provided through the front end. The rear end of the barrel 5 is open, and the ink container 6 can be inserted through the rear end of the barrel 5 having the opening.

The front end of the ink containing portion 6 is brought into contact with the contact portion 52 inside the barrel 5 . The contact portion 52 is made of an annular member arranged inside the barrel 5 , but may be formed integrally with the inner wall of the barrel 5 . The rear end of the ink containing portion 6 abuts the front end of the tail plug.

Ball-point pen tip The ball-point pen tip 2 consists of a tip body 3 made of synthetic resin and a ball 4 rotatably held at the front end of the tip body 3 .

An inward front edge portion 31a protruding radially inward is formed integrally with the front end of the tip body 3, and a ball receiving seat 31b is integrally formed inside the front end portion of the tip body 3 behind the front edge portion 31a. It is formed. The ball receiving seat 31b is formed with a conical inner surface whose diameter increases toward the front. The ball receiving seat 31b has a center hole 31c extending axially through the center of the ball receiving seat 31b, and a plurality (for example, five) extending radially outward from the center hole 31c and axially penetrating through the center hole 31c. of ink guide grooves 31d are formed. A ball holding portion is formed between the front edge portion 31a and the ball receiving seat 31b, and the ball 4 is rotatably held in the ball holding portion. The front end of the ink guide member 7 is inserted into the tip body 3 from the rear, and the front end of the ink guide member 7 is connected to the ink guide groove 31d and the center hole 31c. In addition, the ball 4 is urged forward by the ink guide member 7 or an elastic body (for example, a coil spring) so that the ball 4 is in annular contact with the inner surface of the front edge portion 31a when writing is not performed. may As a result, it is possible to prevent ink from leaking from the front end of the ball-point pen tip 2 and air from entering when writing is not performed.

The chip body 3 is obtained by injection molding of polyacetal resin, for example. Cellulose nanofibers are contained in a dispersed state in the polyacetal resin forming the chip body 3 . The chip body 3 contains 0.1 to 10% by mass of cellulose nanofibers in the total amount of polyacetal resin. The average fiber diameter of the cellulose nanofibers used is in the range of 1 to 500 nm (nanometers). The average fiber diameter (average fiber width) of the cellulose nanofibers was obtained by measuring the diameters of a plurality of fibers (10 or more fibers) using electron micrographs and calculating the average.

A ball 4 having a diameter in the range of 0.3 mm to 1.0 mm (for example, 0.8 mm in diameter) is adopted. Although the material of the ball 4 is not particularly limited, it is generally made of metal or ceramics. The ball 4 is made of, for example, ceramics such as tungsten carbide, zirconium oxide, aluminum oxide, silicon oxide, silicon carbide, or metal such as stainless steel. Also, the ball 4 may be made of a cemented carbide made of ceramics and a metallic binder. As such a cemented carbide, one made of tungsten carbide and a metallic binder such as cobalt or nickel is known.

During writing, the ball 4 is rotatably brought into contact with the ball receiving seat 31b, and ink is supplied from behind to the ball 4 in the ball holding portion through the center hole 31c and the ink guide groove 31d of the ball receiving seat 31b.

The tip body 3 comprises a tapered front tubular portion 31, a rearward stepped portion 32 integrally formed at the rear end of the front tubular portion 31, and a rear tubular portion integrally formed behind the stepped portion 32. and a part 33 .

The front tubular portion 31 has a ball holding portion at its front end. The front side tubular portion 31 protrudes forward from the shaft tube 5 . The rearward stepped portion 32 abuts on the front end of the barrel 5 . The rear side cylinder portion 33 is press-fitted and fixed to the inner surface of the front end hole 51 of the shaft cylinder 5 . The stepped portion 32 is formed on the rear end surface of the collar portion annularly protruding from the rear end of the front cylindrical portion 31 .

A first groove 32a extending in the radial direction and opening radially outward is provided in the rear-facing stepped portion 32 of the air passage chip body 3 . A second groove 33a extending in the axial direction and opening rearward is provided on the outer surface of the rear cylindrical portion 33 of the tip body 3 . The first groove 32a and the front end of the second groove 33a are connected.
The first groove 32a and the second groove 33a are formed at two symmetrical positions.

When the rear cylindrical portion 33 is press-fitted into the front end hole 51 of the barrel 5 and the stepped portion 32 is brought into contact with the front end of the barrel 5 , there is a gap between the front end of the barrel 5 and the stepped portion 32 of the tip body 3 . In addition, the first air passage 81 extending in the radial direction and opening radially outward is formed by the first groove 32a, and at the same time, the inner surface of the front end hole 51 of the shaft tube 5 and the rear side tube portion 33 are separated from each other. A second air passage 82 extending in the axial direction and opening rearward is formed by the second groove 33a between the outer surface and the outer surface. As the first groove 32a and the second groove 33a are connected, the first air passage 81 and the second air passage 82 are connected substantially at right angles to communicate the inside of the barrel 5 with the outside air. A curved (L-shaped) air passage 8 is formed.

Large-diameter portion, small-diameter portion The outer surface of the rear cylindrical portion 33 is provided with a large-diameter portion 331 and a small-diameter portion 332 provided behind the large-diameter portion 331 and having an outer diameter smaller than that of the large-diameter portion 331 . A second groove 33a is formed in the large-diameter portion 331, and the second groove 33a opens rearward from the rear end of the large-diameter portion 331. As shown in FIG. The large-diameter portion 331 of the rear cylindrical portion 33 is fitted and fixed (press-fitted and fixed) to the inner surface of the front end hole 51 .

The outer surface of the ink guide member 7 is held at the rear end opening of the inner hole 3 a of the small diameter portion 332 . Since the outer surface of the ink guide member 7 is held in the inner hole 3a of the small diameter portion 332, the ink guide member 7 can be prevented from bending. The rear end opening of the small diameter portion 332 and the outer surface of the ink guide member 7 are fixed by heat melting or adhesion, thereby preventing the ink guide member 7 from wobbling in the front-rear direction.

Between the rear end of the large-diameter portion 331 and the front end of the small-diameter portion 332, an inclined surface 333 (for example, a conical surface, a convex curved surface, a concave curved surface, etc.) whose outer diameter decreases toward the rear is formed. The inclined surface 333 enables smooth insertion of the ballpoint pen tip 2 into the front end hole 51 when inserting the rear side cylinder portion 33 of the ballpoint pen tip 2 into the front end hole 51 of the shaft tube 5 . The bottom surface of the second groove 33 a in the radial direction is configured by a surface that is continuous with the outer surface of the small diameter portion 332 . The second groove 33a is opened rearward from the rear end (inclined surface 333) of the large diameter portion 331. As shown in FIG. The outer surface of the small diameter portion 332 is not formed with the second groove 33a. The small-diameter portion 332 of the rear cylinder portion 33 serves as an insertion guide when inserting the rear cylinder portion 33 of the ballpoint pen tip 2 into the front end hole 51 of the shaft cylinder 5, so that the ballpoint pen tip 2 can be smoothly inserted into the front end hole 51. It becomes possible.

In the ball-point pen 1 of the present embodiment, a ball-point pen tip 2 in which 5% by mass of cellulose nanofiber is contained in the total amount of polyacetal resin of the tip body 3 is adopted as the ball-point pen tip 2, and a ball 4 having a diameter of 0.8 mm is used. is adopted, and when a water-based ink containing water as a main solvent and a dye as a coloring agent is adopted, a disk type drawing machine (writing angle 75 °, load 100 g, writing speed 4 m / min) is used at room temperature. When the writing resistance value was measured when writing was performed using the pen, the writing resistance value was 19.1 g (grams). On the other hand, when the ball-point pen tip 2 of the ball-point pen 1 of the present embodiment is replaced with the ball-point pen tip 2 made of polyacetal resin that does not contain cellulose nanofibers, the writing resistance value is measured to be 20.2 g ( grams). The value obtained by measuring the writing resistance value is the average value of five writing resistance value data.

The ball-point pen 1 of the present embodiment is a ball-point pen having a ball-point pen tip 2 in which a ball 4 is rotatably held at the front end of a tip body 3 made of synthetic resin. By containing the fiber, the strength of the tip body 3 is improved, damage to the mold when the tip body 3 is obtained by injection molding is suppressed, and proper molding of the tip body 3 can be maintained for a long period of time.

The ball-point pen 1 of this embodiment includes a barrel 5 having a ball-point pen tip 2 at the front end, an ink container 6 disposed inside the barrel 5 and impregnated with water-based ink, and a ball-point pen tip 2 at the front end. and an ink guiding member 7 having a rear end connected to the front end of the ink containing portion 6, the wettability or liquid holding property of the ink in the tip body 3 is improved, and when writing A smooth writing feeling (reduction of writing resistance) is obtained due to the smooth outflow of ink, and when the pen tip is turned upward, the ink descends (drops back) inside the ballpoint pen tip 2, making it impossible to write. can be suppressed.

1 ballpoint pen 2 ballpoint pen tip 3 tip main body 3a inner hole 31 front side cylindrical portion 31a front edge portion 31b ball receiving seat 31c center hole 31d ink guide groove 32 stepped portion 32a first groove 33 rear side cylindrical portion 33a second groove 331 large Diameter portion 332 Small diameter portion 333 Inclined surface 4 Ball 5 Shaft tube 51 Front end hole 52 Abutting portion 6 Ink containing portion 7 Ink guide member 8 Air passage 81 First air passage 82 Second air passage

Claims (5)

A ballpoint pen having a ballpoint tip in which a ball is rotatably held at the front end of a tip body made of synthetic resin,
A ballpoint pen, wherein cellulose nanofibers are contained in the synthetic resin of the tip body. 2. The ballpoint pen according to claim 1, wherein 0.1 to 10% by mass of cellulose nanofiber is contained in the total amount of synthetic resin of said tip body. 3. The ball-point pen according to claim 1, wherein the synthetic resin of said tip body is polyacetal. 4. A ball-point pen according to any one of claims 1 to 3, wherein water-based ink is accommodated therein and said water-based ink can be discharged from the front end of said ball-point pen tip. a barrel having the ball-point pen tip at its front end; an ink reservoir disposed inside the barrel and impregnated with water-based ink; 5. A ballpoint pen as claimed in any preceding claim, comprising an ink guiding member connected to the front end of the section.

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