JP3746973B2 - Water-based ballpoint pen - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water-based ballpoint pen to which a cap is attached when not in use.
[0002]
[Prior art]
In recent years, many water-based ballpoint pens, in which a so-called gel ink that has a high viscosity statically and has a viscosity that decreases with the rotation of the ball during writing, is directly filled in the ink containing tube have been put into practical use. In such a water-based ballpoint pen, gel ink has a lower viscosity than oil-based ink, and therefore has a low flow resistance with respect to the ink containing tube. Further, since the ink consumption with respect to the handwriting length is larger than that of the oil-based ink, the inner diameter of the ink containing tube is larger than that of the oil-based ballpoint pen. Therefore, in order to prevent ink leakage from the tail end opening of the ink containing tube, a grease-like backflow preventive agent is disposed at the rear end of the ink so that the backflow preventive agent advances as the ink is consumed. That is, there is no air in the ink storage tube between the tip of the ballpoint pen tip and the backflow preventing agent, and only gel ink is present.
[0003]
[Problems to be solved by the invention]
By the way, when the cap is mounted on the ballpoint pen body, the internal pressure of the cap tends to increase depending on the structure of the cap. Therefore, a part of the pressurized air in the cap may flow into the ink containing tube through a slight gap between the ball and the chip holding the ball. The inflowing air becomes bubbles and remains in the ink, which may hinder smooth ink outflow during writing.
[0004]
Accordingly, an object of the present invention is to provide a water-based ballpoint pen in which the pressurized air in the cap does not flow into the ink storage tube when the cap is mounted, and the ink flows smoothly during writing.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, the present invention provides a water-based ballpoint pen filled with water-based ink in a shaft cylinder, and in a water-based ballpoint pen in which a cap is mounted, a tip screw at the tip of the shaft cylinder is attached to the tip of the shaft cylinder. A large-diameter portion slightly larger than the outer diameter of the tip connected to the landing portion is formed, and an axial ventilation groove is formed on the surface of the shaft cylinder from the large-diameter portion. Even when the cap is attached, it is exposed on the surface of the shaft tube and communicates with the outside .
Further, the ventilation groove is covered with a grip, and the ventilation hole exposed on the surface of the shaft tube is positioned at the end of the grip.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a main part of an aqueous ballpoint pen according to an embodiment of the present invention. In FIG. 1, a ballpoint pen refill 6 is accommodated in a shaft cylinder 1. A joint 62 in which a chip 63 is fitted in the center hole is connected to the tip opening of the ink containing tube 61 of the ballpoint pen refill 6. The ink containing tube 61 is filled with gel ink that has a high viscosity statically and decreases in viscosity due to the rotation of the ball during writing, and a grease-like backflow preventer (not shown) at the rear end of the ink. ) Is arranged.
[0007]
The chip 63 is formed into a bullet shape with stainless steel, and a ball 64 made of a cemented carbide, for example, having an outer diameter of 0.5 mm is rotatably held in a ball house at the tip of the chip 63. Yes. A small spring (not shown) is disposed in the chip 63, and the ball 64 is repelled by this spring and presses against an inward projection at the tip of the chip 63 when not writing. That is, a valve mechanism is configured by the ball 64 and an inward projection at the tip of the chip 63. When not writing, the valve is closed and ink does not flow out from the tip of the chip 63. The valve opens backward and the ink flows out.
[0008]
As shown in FIG. 2, a tip screwed portion 13 is formed at the tip of the shaft cylinder 1 formed of synthetic resin, and a cap is fitted on the large diameter portion 16 on the tail end side of the tip screwed portion 13. The annular projection 12 is formed. A slightly small-diameter grip fitting portion 11 is formed on the tail end side of the large-diameter portion 16, and a cylindrical shape made of silicon rubber or the like is formed on the grip fitting portion 11 as shown in FIG. The grip 3 is fitted. A ventilation groove 14 is formed in the axial direction from the large diameter portion 16 of the shaft tube 1 and the tail end portion of the grip fitting portion 11. Accordingly, as shown in FIG. 1, the ventilation groove 14 is covered with the grip 3, but the ventilation groove 14 is exposed on the surface of the shaft cylinder 1 at the tail edge of the grip 3, and the exposed ventilation groove 14 is exposed. Is the vent 15. As shown in FIG. 1, the vent 15 communicates with the outside even when the cap 4 is attached.
[0009]
The front end 2 is screwed onto the front end threaded portion 13 of the shaft cylinder 1, but the outer diameter of the front end 2 is slightly smaller than the outer diameter of the large diameter portion 16 of the shaft cylinder 1. The flange portion 62a of the joint 62 of the ballpoint pen refill 6 is clamped by the tip edge of the shaft tube 1 and the inner step portion of the tip 2 so that the ballpoint refill 6 is held.
[0010]
A skirt-like fitting portion 41 is formed in the cap 4, and the cap 4 is formed by the inwardly-shaped annular projection formed on the inner peripheral surface of the fitting portion 41 getting over the annular projection 12 of the shaft tube 1. Attached to the shaft cylinder 1. In addition, a seal ball 5 made of a soft elastic body having discontinuous bubbles is disposed at the inner bottom of the cap 4, and when the cap is mounted, the tip of the chip 63 is sealed by the seal ball 5 so that the ink does not evaporate. It has become.
[0011]
Thus, the cap 2 and the like enter the cap 4 in the process of mounting the cap 4, so the internal volume of the cap 4 is reduced. However, since the gap between the skirt portion 41 and the outer periphery of the tip 2 is small, the cap The air in 4 is difficult to escape to the outside, so the air in the cap 4 is pressurized. However, since the inside of the cap 4 communicates with the outside through the vent groove 14 and the vent 15, the pressurized air escapes to the outside through this path. Therefore, the pressurized air in the cap 4 does not retract the ball 64 against the spring force of the spring, and air can be prevented from entering the ink containing tube 61. For this reason, bubbles are not generated in the ink, and good outflow of ink can be obtained during writing.
[0012]
【The invention's effect】
As described above, the present invention is, ball point pen refill the water-based ink is filled is mounted in the barrel, in an aqueous ballpoint pen cap is mounted, Jikuto tip Former mouth threaded portion at the distal end of the barrel A large-diameter portion slightly larger than the outer diameter of the tip connected to the tube is formed, and an axial ventilation groove is formed on the surface of the shaft cylinder from the large-diameter portion, and a part of this ventilation groove is a cap. Since it is exposed to the outside of the shaft cylinder and communicates with the outside even when installed , the pressurized air inside the cap does not flow into the ink storage tube when the cap is installed, and the ink flows smoothly during writing. It can be a ballpoint pen.
[Brief description of the drawings]
FIG. 1 is a sectional view of an essential part of an embodiment of the present invention.
FIG. 2 is a front view of a main part of a shaft tube.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shaft cylinder 11 Grip fitting part 12 Annular protrusion 13 Tip opening screwing part 14 Venting groove 15 Venting hole 16 Large diameter part 2 Tip opening 3 Grip 4 Cap 41 Skirt part 5 Seal ball 6 Ball-point pen refill 61 Ink receiving pipe 62 Joint 63 Chip 64 ball

Claims (2)

In a water-based ballpoint pen with a ballpoint pen refill filled with water-based ink mounted in the shaft cylinder and a cap attached,
A large diameter portion slightly larger than the outer diameter of the front end connected to the front end screwed portion at the front end of the shaft tube is formed at the front end portion of the shaft tube, and the large diameter portion is formed on the surface of the shaft tube. A water-based ballpoint pen characterized in that a ventilation groove in the axial direction is formed from the outside, and a part of the ventilation groove serves as a ventilation hole and is exposed to the surface of the shaft cylinder and communicates with the outside even when the cap is attached . The water-based ballpoint pen according to claim 1, wherein the ventilation groove is covered with a grip.

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