JP2575795Y2 - Ballpoint pen - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention uses ink having a so-called shear thinning viscosity, which has a high viscosity in a static state, and the viscosity is reduced by rotation of a ball at the time of writing so that the ink flows out. Regarding improvement of ballpoint pens.

[0002]

2. Description of the Related Art Heretofore, there has been known a so-called water-based ballpoint pen in which ink is incorporated in a so-called oil-based ballpoint pen using high-viscosity ink and a fibrous batting, and the ink is guided to a ballpoint pen tip via an ink guide core. ing. Each of them has some drawbacks, but one of the shortcomings is that oil-based ballpoint pens have a disadvantage in that the ink has a high viscosity, and thus the ink has a low writing density and a low writing density. Further, the water-based ball-point pen has disadvantages in that the use of the batting containing the ink increases the cost of members and increases the cost, and that the consumption of the ink is unknown. In addition, under such circumstances, for the purpose of improving each of the drawbacks, the ink having a high viscosity is statically reduced, and the viscosity is reduced by the rotation of the ball at the time of writing, so that the ink having the shear thinning viscosity is discharged. The ballpoint pen used is also known. However, ballpoint pens that use ink with shear thinning have a tendency to evaporate the ink and have a large amount of ink flowing out (to increase the writing density) by increasing the diameter of the ink storage tube to increase the amount of ink loaded. Have many. Further, since the viscosity of the ink is smaller than that of the ink of the oil-based ball-point pen, the flow resistance to the ink storage tube is small. Therefore, ink leakage (ink flows backward at the rear end of the ink storage tube) easily occurs due to a change in atmospheric pressure or temperature, a drop impact, or the like. Normally, a grease-like follower is provided at the rear end of the ink to prevent evaporation of the ink and move following ink consumption during writing, but to suppress backflow of the ink against changes in atmospheric pressure and temperature. Have been. However, even if the follower is provided, when writing upward, when the ink directly under the ball of the chip runs out, the ink head is added directly, so a remarkable backflow occurs, and the inside of the shaft cylinder becomes dirty and the air hole provided in the shaft cylinder causes There is a risk of ink leaking and soiling hands and clothing. In addition, there is a problem that the rear portion of the follower flows backward due to inertia due to the impact when it falls from the rear end side. The situation is not the ratio of the situation that occurs with oil-based ballpoint pens.

[0003]

The object of the present invention is to use an ink which has a high viscosity in a static state, and has a shear thinning viscosity in which the viscosity is reduced by rotation of a ball at the time of writing and the ink flows out. The improvement of the ballpoint pen described above makes it possible to prevent contamination of the inside of the shaft cylinder, hands, and clothes due to the backflow of ink and followers even when the atmospheric pressure and temperature change, the drop impact from the rear end, and the upward writing.

[0004]

The ballpoint pen of the present invention devised to achieve the above object has a joint fixed to the tip of the barrel, and the base is fixed to the barrel, and the joint is elastically deformed. It is composed of a possible synthetic resin, and a press-fitting portion for the chip is provided from the tip, and a valve chamber is provided at the rear communicating with the press-fitting portion, and a ball receiving seat is provided at a rear portion of the valve chamber, and a front inner surface is provided. Has a required number of axial ridges, between which the ball is loosely fitted so that it cannot be pulled out, and the ink storage tube is fixedly connected to the valve chamber, and the ink storage tube has a statically high viscosity With the rotation of the ball at the time of writing, the viscosity is reduced by the rotation of the ball and the ink is discharged, and the ink having the shear thinning viscosity and the trailing end of the ink are provided with a follower that follows with the consumption of the ink,
Further, a tail plug is fixed to the rear end of the barrel, and a buffer member made of an elastic material such as rubber is fixed to the tail plug with its head positioned at the rear end of the barrel.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention shown in FIGS. 1 and 2, a locking cylinder 7 is provided in the first half and a fitting cylinder 13 is provided in the second half. The joint 3 is provided at a required position with an axial slit 8 so that the front end can be elastically deformed in the diameter reducing direction. The inner hole of the locking cylinder 7 has a tip fitting hole 12 from the rear end, a holding portion 11 having substantially the same outer diameter as the outer diameter of the tip 5, and a gap 1 having a tip with an inner diameter appropriately larger than the outer diameter of the tip 5.
The tip 5 is press-fitted into the inner hole of the locking cylinder 7 from the rear end side.

The joint 3 is made of an elastically deformable synthetic resin and is integrally formed. A valve chamber 14 is provided at the rear in communication with the chip fitting hole 12. A concave spherical ball receiving seat 15 is provided at a rear portion of the valve chamber 14, and an axial ridge 16 is provided on an inner surface of the front portion so that a diameter of an imaginary inscribed circle is smaller than a diameter of a ball 19 described later. Are provided at a plurality of positions on the circumference, and a ball 19 is inserted between the ball receiving seat 15 and the ridge 16 while elastically deforming the ridge 16 from the direction of the ridge 16 to allow the ball 19 to play inside the valve chamber 14. It is fitted.
A guide hole 18 communicating with the ball receiving seat 15 is formed behind the valve chamber 14.

A flange 17 is provided at the rear end of the engaging cylinder 7 of the joint 3, and a fitting cylinder 13 is provided behind the flange 17.
Is extended. A cylindrical ink storage tube 4 is press-fitted and fixed to the outer periphery of the fitting cylindrical portion 13 with its front end abutting on the rear end of the flange portion 17.
8 is connected. The ink container 4 is filled with an ink 21 having a statically high viscosity, a viscosity decreasing by rotation of a ball at the time of writing, and a shear-thinning viscosity at which ink can flow out. The rear end is filled with a grease-like follower that prevents evaporation of the ink and that can move following the ink surface by contact with the ink surface as the ink is consumed. The ink storage tube 4 is made of, for example, a transparent PP resin molded product that suppresses evaporation of ink.

Next, a writing portion, to which the chip 5 and the ink containing tube 4 filled with ink are fixed, is inserted into the joint 3 from the tip of the barrel 1, and the flange 17 of the joint 3 is inserted into the front surface of the shaft portion 6. The base 2 having the tapered portion 9 provided on the inner surface by abutting the edges.
Is screwed to the shaft portion 6 of the shaft cylinder 1 in a state where the tapered portion 9 is brought into contact with the front end edge of the locking tube portion 7 of the joint 3. Further, a ventilation hole 20 communicating with the inner hole of the barrel is formed at an appropriate position of the barrel 1, and a tail plug 23 is press-fitted and fixed to a rear end of the barrel 1. Note that a transparent resin molded product is used for the barrel 1 so that the amount of ink consumption can be determined. A buffer member 25 having a head portion 28 at the rear end in the inner hole portion of the tail plug 23 and a locking portion 27 at a tip end of a shaft portion 26 extending forward, the shaft portion 26 is connected to the inner hole portion. , And is locked to the front end of the tail plug 23 by the locking portion 27, and the head 28 is positioned in contact with the rear end of the barrel 1.

[0009]

FIG. 1 shows a writing state in which the tip 5 is directed downward. At this time, the ball 19 comes into contact with the ridge 16 of the valve chamber 14 and passes from the ink containing pipe 4 through the guide hole 18 to the valve chamber 14. The entered ink 21 passes by the ball 19, passes between the ridges 16, and is guided to the tip of the chip 5. The ink statically shows a high viscosity, but the viscosity of the ink drops due to the rotation of the ball at the tip of the chip 5, so that a large amount of the ink flows out, and writing with a high density can be performed without burrs. FIG. 2 shows a state in which the chip 5 is directed upward. At this time, the ball 19 is located at the ball receiving seat 15 of the valve chamber 14 and seals the guide hole 18, so that the ball 19 is written upward and directly below the ball of the chip. Even if the ink runs out, the ink does not clog the head and does not flow backward. In the present invention, the tip 5 is pressed into the tip fitting hole 12 of the locking cylinder 7 of the joint 3 and the front end edge of the locking cylinder 7 abuts against the inner surface tapered portion 9 of the base 2. An external force in the radial direction (diameter decreasing direction) toward the axis acts on the tip of the locking cylinder 7 by the tapered portion 9, and the chip 5 located inside the holding portion 1 is held by the holding portion 1.
1 increases the tightening force. Further, the tip of the locking cylinder 7 is appropriately reduced in diameter by the tapered portion 9 by the gap 10, and the tip 5 is loosened between the tip 5 and the base 2. When the ballpoint pen falls from the rear end side, the head 28 of the cushioning member 25
However, since the impact is reduced, the backflow of the follower 22 is prevented.

[0010]

The configuration and operation of the ballpoint pen according to the present invention are as described above. A valve chamber is provided at an intermediate portion communicating the chip and the ink storage tube, and ink is stored upward by a ball loosely fitted in the valve chamber. And the valve chamber are sealed, and an impact buffer is provided at the rear end of the shaft cylinder, which can prevent the ink and follower from flowing back and contaminating the inside of the shaft cylinder, hands, clothes, etc. Become. Further, since the fixing force of the press-fitting portion of the tip and the joint is strengthened, even if the fitting is loosened slightly, there is no danger of ink leakage or chip detachment. This also guarantees that the reduction in dimensional accuracy leads to a reduction in the number of processes and a reduction in the rejection rate, thereby enabling cost reductions and a high-pressure state in which the press-fitting state of the chip has been stabilized for a long time. We can provide quality products. In addition, since the tip and the base are rattled, effects such as a good brush feeling can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a ballpoint pen according to an embodiment of the present invention, showing a state in which a chip is directed downward.

FIG. 2 is a longitudinal sectional view of a main part of a ballpoint pen according to an embodiment of the present invention, showing a state in which a chip is directed upward;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Cap 3 Joint 4 Ink storage tube 5 Tip 6 Shaft part 7 Locking cylinder part 8 Slit 9 Tapered part 10 Gap 11 Holding part 12 Chip fitting hole 13 Fitting cylinder part 14 Valve chamber 15 Ball receiving seat 16 Protrusion Article 17 Flange 18 Guide hole 19 Ball 20 Vent hole 21 Ink 22 Follower 23 Tail plug 24 Flange 25 Buffer member 26 Shaft 27 Locking part 28 Head

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-171290 (JP, A) JP-A-63-114695 (JP, A) JP-A-4-38479 (JP, U) Utility model registration 2538086 ( JP, Y2) JP 7-17872 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B43K 7/02 B43K 7/08

Claims (1)

(57) [Scope of request for utility model registration] 1. A joint is fixed to a tip of a barrel, and a base is fixed to the barrel. The joint is formed of an elastically deformable synthetic resin. A valve chamber is provided at the rear communicating with the press-fitting part, and a ball receiving seat is provided at the rear part of the valve chamber, and a required number of axial ridges are provided on the inner surface of the front part. The ink storage tube is fixedly connected to the valve chamber, and the ink storage tube has a statically high viscosity, and the viscosity decreases due to the rotation of the ball during writing, and the ink flows out. Done,
A so-called shear thinning ink and a follower are provided at the rear end of the ink to follow the consumption of the ink, and a tail plug is fixed to the rear end of the barrel, and an elastic material such as rubber is attached to the tail plug. A ball-point pen, wherein a shock-absorbing member is fixed with its head positioned at the rear end of the barrel.