JP2002331791A - Ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the inside of the barrel cylinder of a ballpoint pen, hands and apparels from being contaminated by preventing the reverse flow of ink which is generated due to writing facing upward or impacts from occurring; and also, prevent air bubbles from being generated in the ink by a centrifugal process, a temperature change, and deterioration with time; and prevent problems due to the generation of air bubbles from occurring even after a long period of time has passed. SOLUTION: The tip of a ballpoint pen is fixed to the distal end of a joint, and an ink storage tube is fixed to the rear end of the joint. Then, a valve chest is provided at the rear side of the inner hole of the core section of the joint in a manner to communicate with the rear end of the tip. Also, a tapered shape or spherical surface shape ball-receiving seat is provided at the rear section of the valve chest. In this case, a ball valve which can be closely joined to the ball-receiving seat is loosely fitted in the valve chest. In addition, a core is fixed in the inner hole of the core section of the joint, in a space between the front side of the ball valve and the rear end of the tip for this ballpoint pen. In such a ballpoint pen, a low viscosity ink is filled in the ink storage tube, and a grease-form follower, which can move following the ink, is filled at the rear end of the ink. Then, a groove of a proper depth, which penetrates the front and rear ends of the core, is formed at a specified location on the outer peripheral section of the core.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a so-called shear thinning property, in which a low-viscosity ink or a statically high viscosity is used, and the viscosity is reduced by rotation of a ball during writing so that the ink flows out. The present invention relates to improvement of ballpoint pens using ink.

[0002]

2. Description of the Related Art A ballpoint pen using an ink having a shear-thinning property, in which the viscosity is reduced by rotation of a tip ball during writing and the ink flows out, is known. In general, a ballpoint pen using an ink having shear thinning viscosity has a large amount of ink flowing out, so that the diameter of an ink storage tube is increased to increase the amount of ink loaded. In addition, since the viscosity of the ink is smaller than that of a normal oil-based ballpoint pen, the ink tends to flow backward due to its own weight or impact. For this purpose, a grease-like follower is provided at the rear end of the ink, which normally moves following the consumption of the ink during writing, but suppresses the backflow of the ink against its own weight or impact. However, even when the follower is provided, there is a problem that, when writing upward, when ink runs out on the back surface of the tip ball, air flows in, and the ink head is added directly, so that a remarkable backflow occurs and soils hands and clothes. Further, since the viscosity of the ink is low and the amount of the ink flowing out is large, if a gap is formed between the tip ball and the ball holding portion of the chip when the chip side is directed downward, a problem of bleeding of the ink (DC) occurs.

[0003] Further, since the ink exists in a closed space cut off from the outside air, if gas is mixed in the ink, the gas grows and becomes bubbles when left at a high temperature or for a long period of time, and the bubbles become bubbles. When present at the writing tip, there is a problem that not only adversely affects the outflow of ink but also makes writing impossible. Also, if the writing tip is left facing down, a space is created between the ink and the ink follower, which causes problems such as a backflow of the ink. Therefore, in order to solve the problem, defoaming by natural leaving and defoaming treatment for mechanically removing gas in the ink have been mainly performed. Also, in the manufacture of a ballpoint pen that fills an ink storage tube with ink and a follower (ink follower) having shear thinning, air is supplied together with the ink when the ink storage tube is filled with the ink and the follower. There's a problem. In addition, if air stays in the chip or the like, the ink passage is blocked and hinders ink outflow, resulting in poor ink outflow. Therefore, it is necessary to discharge air out of the ballpoint pen.However, since the ink has a shear thinning viscosity, the viscosity is high in the stationary state, and the follower has a high viscosity. There is a problem that it is not naturally discharged from the end opening.
Therefore, air is forcibly discharged from the rear end of the opening of the ink storage tube by applying the ballpoint pen filled with the ink and the follower to the centrifuge with the tip end facing downward.

In order to chemically suppress the generation of bubbles, a method of defining the amount of dissolved oxygen in the ink (Japanese Patent Laid-Open No. 8-183923) and a method of adding a gas-absorbing substance to the ink are disclosed. (Japanese Unexamined Patent Publications Nos. 11-293175 and 11-298483) are known, but in the former, when a molded article made of polypropylene or the like having relatively good gas permeability is used as an ink storage tube, it takes 2 to 3 years. It is difficult to appropriately maintain the amount of dissolved gas in the ink in an unsaturated state for a long period of time, and the latter cannot expect a long-term suppression effect on a yearly basis.

[0005]

As a result of intensive studies on the causes of the generation of bubbles generated inside the ball-point pen, it was found that the gas remaining in the ball-point pen which could not be completely removed in the centrifugation step was the main cause. . If the ballpoint pen is left at a high temperature or for a long period of time, the moisture in the ink evaporates, changing the components of the gas (residual gas) left inside the ballpoint pen, and keeping the gas components in equilibrium with the outside air. It has also been found that the squeezing force acts as an attractive force to absorb air components into the ballpoint pen from the outside of the PP resin ink container or the like, and as a result, residual gas grows and bubbles are generated. Accordingly, an object of the present invention is to provide a so-called shear thinning ink (medium viscosity ink) that has a low viscosity ink or a statically high viscosity, and the viscosity of the ink decreases due to the rotation of the ball during writing and the ink flows out. (Referred to as ink or gel ink) is an improvement of the ballpoint pen, which prevents backflow of ink caused by upward writing or impact of the ballpoint pen and direct current when the tip side is placed downward, so that the inside of the ballpoint pen barrel and the hand, An object of the present invention is to make it possible to prevent clothes from being stained, to prevent air bubbles from being generated in the ink due to a centrifugal process, a change in temperature, and a change with time, and to prevent a problem due to the generation of air bubbles even after a long period of time.

[0006]

According to a first aspect of the present invention, there is provided a ballpoint pen in which a tip of a ballpoint pen is fixed to a tip of a joint and an ink storage tube is fixed to a rear end of the ballpoint pen. A valve chamber is provided at the rear in communication with the rear end, and a tapered or spherical ball receiving seat is provided at the rear of the valve chamber, and a ball valve capable of being in close contact with the ball receiving seat is loosely fitted into the valve chamber. In a ballpoint pen in which a top is fixed in the bore of the shaft center between the front of the ball valve and the rear end of the chip, low viscosity ink follows the ink at the rear end of the ink. A movable grease-like follower is filled, grooves are formed at appropriate locations on the outer peripheral portion of the top and through the front and rear ends thereof, and when the chip side is upward, the ball valve comes in close contact with the ball receiving seat. The hole is sealed and the tip side is facing down In the closed ball valve at the rear end of the frame together with state it is released abuts the bore hole, wherein the ink is configured to flow into the chip through the grooves or the like.

According to a second aspect of the present invention, there is provided a ball-point pen according to the first aspect, wherein a spring is laid in the chip inner hole with the rear end portion abutting on the front end of the top. The tip of the tip ball, which is rotatably held by the tip of the tip, is pressed against the tip of the tip, and the tip ball is brought into close contact with the inner edge of the tip ball holding portion. The configuration is such that the close contact with the inner edge of the holding portion is released, and the ink can flow out with the rotation of the tip ball.

[0008]

1 and 2 show a first embodiment of the present invention. First, as shown in the figure, the joint 3 is integrally formed of an elastically deformable synthetic resin, and has a locking cylinder 7 in the first half and a fitting cylinder 12 in the second half. The part 7 is provided with a rib 8 inclined forward in the axial direction at a required position on the circumference. A tip fitting hole 10 is formed in the locking cylinder part 7 from the front end, and the chip 5 is press-fitted into the tip fitting hole 10 from the rear end side. In order to prevent the chip 5 from being pulled out, a convex engaging portion 11a is formed on the shaft portion 11 of the chip as necessary, so that the chip fitting hole 10 is formed as a slightly small hole behind the chip fitting hole 10. The locking portion 11a is bitely locked in the hole 10 #. This means that fitting 3 is PP
In the case of a resin or the like, care is taken to prevent the chip from coming out of the joint even if the crimping force of the chip is reduced due to creep due to aging or temperature change.

The joint 3 is provided with the tip fitting hole 10,
A valve chamber 13 is provided at the rear in communication with 10 °.
A ball receiving seat 14 having a tapered or spherical shape is provided at the rear end of the valve chamber 13. A guide hole 20 communicating with the ball receiving seat 14 is formed behind the valve chamber 13, and a ball valve 15 is loosely fitted in the valve chamber 13. Further, the joint 3 is provided between the ball valve 15 and the rear end of the shaft portion 11 of the chip.
The top 16 is fixed in the inner hole of the shaft center portion. Top 16
Is provided with a required number of ribs 16d on the outer periphery of a shaft portion 16a having a hole 16c in the shaft center, and the outer end of the rib engages with the wall of the shaft center portion inner hole, and the top 16 It is fixed to the joint. Further, a groove having an appropriate depth is formed between the ribs at the front and rear ends of the top.

On the other hand, the tip 5 is caulked so that the tip ball 5a is rotatably held with the tip ball 5a substantially in contact with a seat having a channel 5b into which ink can flow. Further, a spring 17 is laid in the inner hole of the chip 5 in a state where the rear end portion is in contact with the front end of the top 16. An upright bar shaft 17a is formed in front of the spring 17, and the front end of the bar shaft 17a is pressed against the rear end of the tip ball 5a. The tip ball 5a is provided so as to be in liquid-tight contact with the inner edge of the ball holding portion (formed by caulking or the like) of the chip 5 by the pressing.

As described above, when the tip side is downward, the ball valve 15 comes into contact with the rear end of the top 16, and ink flows through the guide hole 19, the groove 16 b, the hole 16 c, and the inner hole of the tip 5, and the back surface of the tip ball 5 a. It can flow up to.

A flange 18 is provided at the rear end of the engaging cylinder 7 of the joint 3, and a fitting cylinder 12 is provided behind the flange 18.
Is extended. A cylindrical ink storage tube 4 is press-fitted and fixed to the outer periphery of the fitting cylindrical portion 12 with its front end abutting on the rear end of the flange portion 18.
9 in communication. The ink container 4 is filled with a low-viscosity ink or an ink 20 having a statically high viscosity, and having a shear-thinning viscosity such that the viscosity is reduced by rotation of a ball during writing so that the ink can flow out. The trailing end of the ink 20 is filled with a grease-like follower that can move following the ink surface as the ink is consumed. (Not shown)

As described above, the ball-point pen constituted by fixing the tip 5 and the ink storage tube 4 filled with ink to the joint 3 is inserted into the barrel 1, and the flange of the joint 3 is provided on the front surface of the shaft 6. The base 2 having the step 9 on the inner surface thereof is brought into contact with the rear end edge of the base 19 and the step 9 is brought into contact with the peripheral surface of the rib 8 of the joint 3 so that the shaft of the shaft cylinder 1 is brought into contact therewith. A ball-point pen writing instrument is formed by screwing it to the section 6.

FIG. 3 shows a second embodiment of the present invention. Since it is basically the same as the first embodiment, only the differences will be described. The front end of the spring 22 inserted into the chip 5 forms a seat, and a pushing body 21 having a rod shaft portion 21a is disposed at the front portion thereof, and the tip of the rod shaft portion 21a is located at the rear end of the tip ball 5a. It is made to contact in a pressing manner.

FIG. 4 shows a third embodiment of the present invention, which is also the same as the first embodiment, and only the differences will be described. The top 23 has a required number of ribs 23b formed on the outer periphery of the shaft portion 23a of the shaft center, and the top 16 is located between the ribs.
A deeper groove 23c is formed.

[0016]

First, FIG. 1 shows a state before writing with the tip 5 facing down. At that time, the ball valve 15 comes into contact with the rear end of the top 16 and the guide hole 19 is opened. The ink 20 that has entered the valve chamber 13 from the ink storage tube 4 through the guide hole 19
Is guided to the back of the tip ball 5a through the groove 16b and the hole 16c of the top 16. In this state, the tip ball 5a is brought into close contact with the inner edge of the ball holding portion of the chip by the pressing of the rod shaft portion 17a, so that direct current of ink is prevented. In addition, since the tip ball 5a is slightly retracted by the writing pressure, a gap is generated and ink can flow out. In the case of gel ink,
By the writing, the rotation of the tip ball 5a lowers the viscosity, causing a large amount of ink to flow out.

FIG. 2 shows a state in which the tip 5 is directed upward. At this time, the ball valve 15 is in close contact with the ball receiving seat 14 of the valve chamber 13 to seal the guide hole 19, so that the tip ball 5a is written upward. Even if the ink on the back runs out, the ink does not flow backward. Therefore, when the tip 5 is turned downward, the ink can immediately flow out, and the writing is prevented from being rubbed.
(By the way, in a structure without a ball valve, ink acts in the backward direction when writing upwards, so air is trapped in the chip, and ink does not follow immediately when writing downwards. Are accumulated.

The embodiment is suitable for a ballpoint pen which has a low ink viscosity and a large amount of ink bleeding, and which is mounted on a ballpoint pen having a thick writing line or a cap-off writing instrument such as a knock type. If there is a seal cap, the ball valve may have only a structure in which the ball hole is in close contact with the ball seat of the valve chamber to seal the guide hole, or even if it is a knock type, the writing line is thin, so the ink storage tube The thin ballpoint pen may have only a structure in which the tip ball is brought into close contact with the inner edge of the ball holding portion of the chip by the pressing of the spring.

Conventionally, only a minute gap for guiding ink is provided between the tip end of the chip and the ball valve, or a complicated step is provided. However, there was a problem that bubbles were caught when defoaming by the method, and the defoaming was not sufficiently performed.
By providing a required number of ribs 16d on the outer peripheral portion of a, a groove having an appropriate depth is formed between the ribs at the front and rear ends of the top, so that air bubbles can be freely discharged by centrifugation. .

[0020]

The configuration and operation of the ballpoint pen of the present invention are as described above. As one, a backflow of ink due to upward writing or impact can be prevented by a ball valve that is loosely fitted in the valve chamber. Accidents that stain clothes etc. are prevented.
Also, as 2, the direct pressure is prevented by placing the tip ball close to the inner edge of the tip holding portion with a spring, so that direct current is prevented when the ball is placed downward with the cap off, and the inside of the shaft cylinder, hands and clothes are stained. Is prevented. In addition, by using the above two means in combination, the ink immediately follows the upward writing or the impact, so that the ink is prevented from being flared. In addition, since defoaming can be reliably performed by centrifugal processing, ink deficiency caused by air stagnating inside the chip and blocking the ink passage and preventing ink bleeding is solved, and a ballpoint pen with no writing impossible is provided. It becomes possible.

[Brief description of the drawings]

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

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

FIG. 3 is a longitudinal sectional view of a main part of a ballpoint pen according to a second embodiment of the present invention, showing a state where a chip is directed upward;

FIG. 4 is a longitudinal sectional view of a main part of a ballpoint pen according to a third embodiment of the present invention, showing a state where a chip is directed upward;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Base 3 Joint 4 Ink storage tube 5 Tip 5a Tip ball 5b Channel 6 Shaft 7 Locking cylinder 8 Rib 9 Step 10 Chip fitting hole 10a Chip fitting hole 11 Shaft 11a Lock 12 fitting Joint tube part 13 Valve chamber 14 Ball seat 15 Ball valve 16 pieces 16a Shaft part 16b Groove 16c Hole 16d Rib 17 Spring 17a Rod part 18 Flange part 19 Guide hole 20 Ink 21 Push body 21a Rod part 22 Spring 23 Piece 23a Shaft 23b Rib 23c Groove

Claims (2)

[Claims] 1. A tip of a ballpoint pen at a tip of a joint,
An ink storage tube is fixed to the rear end, and a valve chamber is provided at the rear side in communication with the rear end of the chip through the inner bore of the joint, and a tapered or spherical ball receiving seat is provided at the rear of the valve chamber, In a ball-point pen in which a ball valve capable of being in close contact with a ball receiving seat is loosely fitted in a valve chamber, and further, a top is fixed to a bore in a shaft center portion between a front portion of the ball valve and a rear end of the chip. The ink storage tube is filled with a low-viscosity ink at the rear end of the ink in a grease-like follower that can move following the ink. When the tip side is upward, the ball valve is in close contact with the ball receiving seat and the guide hole is sealed, and when the tip side is downward, the sealed state is released and the ball valve contacts the rear end of the top. Ink in the chip through the guide hole, groove, etc. A ballpoint pen configured to flow in. 2. A spring is laid in an inner hole of the chip in a state in which a rear end portion is in contact with a front end of a top, and a rear end of the tip ball rotatably held at a tip end portion of the chip is pressed by a tip of the spring. Then, the tip ball is brought into close contact with the inner edge of the ball holding portion of the chip, the close contact between the tip ball and the inner edge of the ball holding portion of the chip is released by writing pressure, and ink can flow out with the rotation of the tip ball. The ballpoint pen according to claim 1, wherein the ballpoint pen is configured to: