JP3730584B2 - Ballpoint pen - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a ballpoint pen in which a refill in which an ink containing tube is filled with a gel ink having a so-called shear thinning viscosity that has a high viscosity statically and decreases in viscosity by the rotation of the ball during writing is mounted in a shaft cylinder. About.
[0002]
[Prior art]
Although ballpoint pens using low-viscosity inks and ballpoint pens using high-viscosity oil-based inks have excellent characteristics, there are defects due to the characteristics of the inks. A ballpoint pen using a gel ink having a so-called shear thinning viscosity in which the viscosity is lowered by the rotation of the ball at the time of writing has been put into practical use. In such a ballpoint pen, gel ink is directly filled in the ink storage tube of the refill mounted in the shaft cylinder, and a grease-like is formed on the tail end side of the ink so that the ink does not leak from the tail end opening of the ink storage tube. A backflow prevention agent is arranged. Then, as the ink is reduced by writing, the backflow preventive agent advances along the inner wall of the ink storage tube. However, since the backflow preventive agent is in the form of grease, there is a risk that the backflow preventive agent breaks and ink leaks when a strong impact is applied to the writing instrument.
[0003]
As a countermeasure against ink leakage due to the destruction of the backflow preventive agent, a plug that has air permeability but does not allow ink to pass through is packed in the opening of the tail end of the ink containing tube, so that ink leaks even if the backflow preventive agent breaks. There are times when it is made not to take out.
[0004]
[Problems to be solved by the invention]
By the way, in the ballpoint pen that mounts the refill in the shaft cylinder, when the ink is used up, it is replaced with a new refill. It is necessary to pack the tail end opening of the receiving tube. Therefore, many plugs are required, and there is a problem that it takes time to assemble the refill.
[0005]
Therefore, the present invention has an object to provide a ballpoint pen that can prevent ink leakage with a simple structure, without having to plug all the refills in advance in the tail end opening of the ink containing tube. To do.
[0006]
[Means for Solving the Problems]
In order to achieve this object, the invention of claim 1 is characterized in that a gel ink that has a high viscosity statically and decreases in viscosity due to rotation of a ball during writing is filled in the ink containing tube, and the tail end side of the ink A refill with a grease-like backflow preventing agent is mounted on the shaft tube, and a tail plug is fitted to the tail end opening of the shaft tube, or a pen body portion at the tip of the refill is placed on the tail end opening of the shaft tube. In a ballpoint pen in which a knock member for protruding and retracting from the tip opening of the shaft tube is arranged, a cylindrical leak prevention member is fixed to the tail plug or the knock member, and the tip portion of the leak prevention member is attached to the tail end portion of the ink containing tube. A small gap is formed between the inner peripheral surface of the ink containing tube and the outer peripheral surface of the leakage preventing member.
Further, as in the invention of claim 2, it is preferable that the gap between the inner peripheral surface of the ink containing tube and the outer peripheral surface of the leakage preventing member is 0.05 to 0.5 mm.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an embodiment of a knock type ballpoint pen. In FIG. 1, a shaft cylinder 10 includes a rear shaft 11 and a front shaft 12 that are formed of synthetic resin, and a front end opening 15 is formed at the front end of the front shaft 12. A grip 14 made of a soft synthetic resin is disposed on the outer periphery of the front shaft 12. A cylindrical fixing portion 41 of the clip 40 is fixed to the tail end portion of the rear shaft 11.
[0008]
A refill 20 is mounted in the shaft cylinder 10 so as to be movable back and forth in a state where the refill 20 is springed to the tail end side by a coil spring 26. A joint 22 is fitted into the tip opening of the ink containing tube 21 of the refill 20, and a pen body portion 23, which is a ballpoint pen tip, is fitted into the center hole of the joint 22. The ink containing tube 21 is filled with ink I, and a grease-like backflow preventing agent 25 is disposed at the rear end of the ink I.
[0009]
Ink I contains pigments or dyes that are colorants, resins, thickeners, water-soluble solvents, and contains dispersants and preservatives as necessary. This is a gel ink whose viscosity is lowered by the rotation of the ball. The viscosity of the ink I is 20 mPa · s or more. In addition, the backflow preventive agent 25 is mainly composed of polybutene, silicone oil, mineral oil or the like, and is appropriately thickened with silica gel, metal soap or the like.
[0010]
The pen body portion 23 is molded into a bullet shape with stainless steel, and the ball 24 made of a cemented carbide having an outer diameter of 0.5 mm, for example, is freely rotatable in a ball house at the tip of the pen body portion 23. Be embrace. A small spring (not shown) is disposed in the pen body portion 23, and the ball 24 is repelled by this spring and presses against an inward projection at the tip of the pen body portion 23 when not writing. That is, the valve mechanism is configured by the ball 24 and the inward projection at the tip of the pen body portion 23. When not writing, the valve is closed so that the ink does not flow out from the tip of the pen body portion 23. Since the valve is closed, air does not enter from the tip of the pen body 23. At the time of writing, the ball 24 is retracted by the writing pressure, the valve is opened, and the ink flows out.
[0011]
The refill 20 mounted in the shaft cylinder 10 is moved back and forth by a well-known double-knock type retracting mechanism using a rotor 30, and the pen body portion 23 protrudes and retracts from the tip opening 15. That is, although detailed explanation is omitted, when writing, the knock member 50 disposed in a state in which the pen body portion 23 protrudes from the tail end of the shaft tube 10 from the state of FIG. When the knocking operation is performed, the refill 20 moves forward, and the pen body portion 23 protrudes from the tip opening 15 so that writing can be performed. When the knocking operation is performed again, the refill 20 is retracted, and the pen body portion 23 is immersed in the shaft tube 10 to return to the state shown in FIG.
[0012]
A columnar leakage preventing member 60 is fixed to the knock member 50, and a tip end portion 60 a protrudes forward from the knock member 50. When the refill 20 is disposed at a predetermined position in the shaft cylinder 10 during assembly or refill replacement, the tip end portion 60a of the leakage preventing member 60 enters the tail end portion 21a of the ink containing tube 21, and as shown in FIG. A small gap S is formed between the inner peripheral surface of the ink containing tube 21 and the outer peripheral surface of the leakage preventing member 60. The gap S has sufficient air permeability, but prevents the ink from flowing back and leaking due to the capillary force, and the interval is preferably in the range of 0.05 to 0.5 mm. If the gap S is smaller than 0.05 mm, the air permeability is insufficient, and if it is larger than 0.5 mm, the capillary force is insufficient and the backflow prevention effect is reduced.
[0013]
FIG. 3 shows an embodiment of a non-knock type ballpoint pen. The same refill 20 as shown in FIG. 1 is mounted in the shaft cylinder 10, and the pen body portion 23 always protrudes from the tip opening 15 of the tip 13. A cap 80 is fitted to the tip of the shaft tube 10 when not writing.
[0014]
A tail plug 70 is fitted to the tail end of the shaft tube 10, and a columnar leakage preventing member 60 is fixed to the tail plug 70, and a tip end portion 60 a projects forward from the tail plug 70. . When the refill 20 is arranged at a predetermined position in the shaft cylinder 10 during assembly or refill replacement, the tip end portion 60a of the leakage preventing member 60 enters the tail end portion 21a of the ink containing tube 21, and in the case of the above embodiment Similarly, a small gap S is formed between the inner peripheral surface of the ink containing tube 21 and the outer peripheral surface of the leakage preventing member 60.
[0015]
In this way, since there is a small gap S between the inner peripheral surface of the ink containing tube 21 and the outer peripheral surface of the leakage preventing member 60, even if the backflow preventive agent 25 is broken by an impact or the like, the ink has a capillary force. Therefore, the ink does not pass through the gap S where the ink works, and ink leakage can be prevented. In addition, when the leakage preventing member 60 is fixed to the tail plug 70 or the knocking member 50 and the refill 20 is disposed at a predetermined position in the shaft tube 10 during assembly or refilling, the leading end of the leakage preventing member 60 accommodates ink. Since it is inserted into the tail end side of the tube 21, it is not necessary to attach a plug or the like to the refill 20 in advance, the number of parts is small, and the refill 20 can be easily assembled.
[0016]
【The invention's effect】
As described above, according to the present invention, the gel ink is filled in the ink containing tube, which has a statically high viscosity and decreases in viscosity due to the rotation of the ball at the time of writing. A refill in which an inhibitor is disposed is mounted in the shaft tube, and a tail plug is fitted into the tail end opening of the shaft tube, or the pen body portion at the tip of the refill is inserted into the tail end opening of the shaft tube. In a ballpoint pen with a knock member to be moved in and out, a columnar leakage prevention member is fixed to the tail plug or the knock member, and the tip of the leakage prevention member is inserted into the tail end portion of the ink storage tube to store the ink. Since a small gap is formed between the inner peripheral surface of the tube and the outer peripheral surface of the leakage preventing member, it is not necessary to plug all the refills in advance in the tail end opening of the ink containing tube, and a simple structure To prevent ink leakage Can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an embodiment of the present invention. FIG. 2 is a cross-sectional view of a tail end portion of an ink containing tube.
FIG. 3 is a cross-sectional view of another embodiment.
[Explanation of symbols]
[Explanation of symbols]
10 shaft cylinder 11 rear shaft 12 front shaft 15 tip opening 20 refill 21 ink containing tube 22 joint 23 pen body portion 24 ball 25 backflow preventive agent 26 coil spring 30 rotor 40 clip 50 knocking member 60 leakage preventing member 70 tail plug 80 cap

Claims (2)

Statically high viscosity, gel ink whose viscosity is reduced by rotation of the ball during writing is filled in the ink containing tube, and a refill in which a grease-like backflow preventing agent is arranged on the tail end side of the ink is a shaft. Mounted in the cylinder, a tail plug is fitted into the tail end opening of the shaft cylinder, or a knock member for causing the pen body portion at the tip of the refill to protrude from the tip opening of the shaft cylinder is inserted into the tail end opening of the shaft cylinder. In the placed ballpoint pen,
A columnar leakage preventing member is fixed to the tail plug or the knock member, and the tip of the leakage preventing member is inserted into the tail end of the ink containing tube, and the inner peripheral surface of the ink containing tube and the leakage preventing member A ballpoint pen characterized in that a small gap is formed between the outer peripheral surface of the pen. The ballpoint pen according to claim 1, wherein the gap between the inner peripheral surface of the ink containing tube and the outer peripheral surface of the leakage preventing member is 0.05 to 0.5 mm.

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