JPH1086584A - Ball-point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent back flow of ink by upward writing and a shock in the ball-point pen with a fine point for using ink of low viscosity or ink having shear-thinning properties which basically has low viscosity but statically has high viscosity and flows out because viscosity is lowered by rotation of a ball at time of writing. SOLUTION: The ball-point pen is constituted by providing the tip 5 of the ball-point pen formed of a capillary, in which the diameter of tip ball 5a is 0.3ϕ 0.4ϕ, in the tip of a joint 3 and providing an ink-holding pipe 4 in the rear. A valve chamber 15 is provided in the axial center of a bushing 13 and a taper-shaped or spherical ball receiving seat 14 is provided in the rear of the valve chamber 15. Necessary numbers of projected lines 19a are provided on the front circumferential wall of the valve chamber 15. A ball valve 21 closable to the ball receiving seat 14 elastically deforms the projected lines 19a and is loose-inserted so as not to be pulled out to the inside of the valve chamber 15. On one side, a barrel part 6 is formed to contact- bond the tip 5 to the tip of the joint 3 and also the bushing 13 is fixed to the axial center of the rear inner hole in a closely inserted shape. Further, the ink-holding pipe 4 is fitted to the outer periphery of a fitting cylinder part 7 in the rear of the joint 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a low-viscosity ink or a low-viscosity ink which basically has a low viscosity, but has a high viscosity in a static state. The present invention relates to an improvement of a ballpoint pen using an ink which is discharged and has so-called shear thinning viscosity.

[0002]

2. Description of the Related Art The applicant of the present invention discloses, in Japanese Utility Model Publication No. 4-52067, a mechanism for preventing backflow of ink of a ballpoint pen provided with a valve chamber into which a ball is loosely fitted. In this case, a required number of protrusions are provided in a valve chamber in which a ball is loosely fitted with a synthetic resin mouth plug to prevent the ball from being pulled out, and a gap formed between the protrusions at the time of writing. And the ink flows to the chip. Further, a ballpoint pen using an ink having a shear thinning viscosity, in which the viscosity is reduced by the rotation of the tip ball during writing and the ink flows out, is known. In general, a ballpoint pen using ink having shear thinning viscosity has a large amount of ink flowing out (to increase the writing density), and has a large diameter of the ink storage tube to increase the amount of ink loaded. or,
Since the viscosity of the ink is smaller than that of the oil-based ball-point pen ink, 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 the ink's 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 ink during writing, but suppresses the backflow of the ink against its own weight or impact. However, even when the follower is provided, if the ink immediately below the ball of the chip runs out when writing upward, there is a risk that a remarkable backflow occurs because the ink head is added directly and the hands and clothes are stained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-viscosity ink or a low-viscosity ink which basically has a low viscosity and the viscosity is reduced by rotation of a ball during writing so that the ink flows out. Improvement of a ballpoint pen using ink
It is possible to prevent backflow of ink caused by upward writing or impact of a ballpoint pen, and to prevent contamination of the inside of the barrel of the ballpoint pen, hands, and clothes. When the diameter of the tip ball is φ0.
An object of the present invention is to satisfy the above-mentioned problems as a ballpoint pen for fine writing with a diameter of 3, 0.4.

[0004]

In order to achieve the above object, a ballpoint pen according to the present invention has a tip of a small ballpoint pen having a tip ball diameter of .phi.0.3 or .phi.0.4 at the end of a joint, and ink is accommodated in the back. In a ball-point pen having a tube, the bush is provided with a valve chamber at its axis, and a tapered or spherical ball seat at the rear of the valve chamber is provided with a required number of projections on the front peripheral wall of the valve chamber. A ridge is provided, and a ball valve which can be brought into close contact with the ball receiving seat elastically deforms the ridge so as to be loosely fitted into the valve chamber without being pulled out, while forming a shaft portion for crimping the tip to the tip of the joint. At the same time, the bush is tightly fixed to the axis of the rear inner hole, and an ink storage tube is fitted around the outer periphery of the fitting cylinder portion at the rear of the joint. Or, basically, it has low viscosity but statically high viscosity. The ink is filled with a so-called shear-thinning ink in which the viscosity is reduced by the rotation of the tip ball at the time described above and the ink flows out, and a follower that follows the consumption of the ink is provided at the rear end of the ink. When the ball valve is in the upward direction, the ball valve is in close contact with the ball receiving seat, and the guide hole is sealed. When the chip side is in the downward direction, the sealed state is released, and the ball valve is in contact with the rear end of the ridge, so that the guide hole and the valve are closed. The ink flows into the chip through a chamber, a groove formed between the ridges, and the like.

[0005]

1 to 4 show a first embodiment of the present invention. First, as shown in the figure, a locking cylinder 7 is provided in the first half of the joint 3 and a fitting cylinder 12 is provided in the second half, and the locking cylinder 7 on the front side is provided.
Is provided with a rib 8 inclined forward in the axial direction at a required position on the circumference. An inner shaft portion 10 having a chip fitting hole 10a at the center from the front end of the locking cylinder portion 7 is formed, and a holder fitting hole 10b is formed outside the inner shaft portion 10.
The chip 5 is pressed into the chip fitting hole 10a from the rear end side. In addition, the holder 1 is fitted to the chip 5.
1 is press-fitted to the inner shaft portion 10, and the holder 11 is substantially pressed into the holder fitting hole 10b. A window 12a is formed in a side surface of the fitting tube 12.

The joint 3 is made of an elastically deformable synthetic resin and is integrally formed, and has a large-diameter hole rearwardly communicating with the chip fitting hole 10a.
On the other hand, the bush 13 has a ball receiving seat 14 having a tapered or spherical shape at the axis, and a conducting hole 18 penetrating from the center of the ball receiving seat 14 to the rear end. Further, a space in front of the ball receiving seat 14 is formed as a valve chamber 15, and a required number of elastic pieces 19 are formed on a peripheral portion of a shaft portion in front of the bush at a predetermined location with a slit 19b. In addition, a ridge 19 a is provided on the inner surface of the elastic piece 19. Further, a protrusion 16 is formed circumferentially on the outer peripheral portion of the bush 13, and a locking portion 17 having a circumferential shape or a ridge is formed rearward. As described above, the valve chamber 15 is formed between the ball receiving seat 14 and the ridge 19a, and the ridge 19a is elastically expanded from the front end so that the valve chamber 15
The ball valve 21 is loosely fitted therein.

The tip 5 is a thin tube made of stainless steel or the like. The tip ball 5a rotates while the tip ball 5a is substantially in contact with a receiving seat 5b having a channel into which ink can flow by being pressed and caulked at three locations on the outer periphery. It is crimped to be freely held. The spring 20 has an upright straight portion 20b formed forward and a winding portion 20a formed rearward. The spring 20 is inserted into the hole of the joint 3 and the straight portion 20b is inserted into the inner hole of the chip 5. I do.

The bush 13 is inserted from the rear end of the joint 3, and the locking portion 17 is elastically engaged with the window 12a to be positioned and fixed in the hole behind the joint 3. At this time, the protrusion 16 comes into close contact with the peripheral surface of the hole. Further, when the bush 13 is fixed, the ball valve 21 is restrained by the peripheral surface of the joint 3 hole portion, so that the ball valve 21 cannot be reliably pulled out by the ridge 19a. There are various methods for fixing the bush 13 such as a method of providing a groove and a protrusion between the peripheral surface of the hole of the joint 3 and the outer peripheral portion of the bush 13 to elastically lock the bush 13, and is not limited to the embodiment. Things.

Further, the rear end of the winding portion 20a of the spring comes into contact with the tip of the bush 13, and the tip of the straight portion 20b comes into contact with the back surface of the tip ball 5a in a pressing manner. still,
The tip ball 5a is brought into close 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 21 comes into contact with the rear end of the ridge 19a, and ink flows through the guide hole 18, the valve chamber 15, the groove between the ridges and the like. It enters the inner hole of the chip 5 and reaches the back of the tip ball 5a.

A flange 7a is provided at the rear end of the engagement cylinder 7 of the joint 3, and a fitting cylinder 12 is provided behind the flange 7a.
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 7a.
8 is connected. The ink in the ink container 4 has a low viscosity or basically a low viscosity, but has a high viscosity statically, and the viscosity is reduced by rotation of the ball during writing, so that the ink can flow out. A grease-like follower 30 that is filled with an ink 28 having a shear thinning property and is movable at the rear end of the ink 28 so as to come into contact with and follow the ink surface as the ink is consumed.
Is filled. A follower rod 31 made of resin and having a specific gravity equivalent to that of the follower 30 is immersed in the follower 30. The follower rod 31 is provided as needed (when the sectional diameter of the ink storage section is large and the head of the ink is large, and when the viscosity of the ink is low and the ink head cannot be supported). The follower rod is formed as required, such as a rod having a round or irregular cross section, a cylinder, a cup, or the like.

As described above, the refill of a ball-point pen constituted by fixing the tip 5 and the ink containing tube 4 filled with ink to the joint 3 is inserted into the shaft cylinder 1, and the joint 3 is attached to the front surface of the shaft portion 6. The rear end edge of the flange 7a is abutted, and the base 2 provided with the step 9 on the inner surface thereof is brought into contact with the peripheral surface of the rib 8 of the joint 3 in a state where the step 9 is brought into contact with the peripheral surface of the rib 8. A ballpoint pen is formed by screwing to the shaft portion 6 of the ballpoint pen.

FIG. 5 shows a second embodiment of the present invention. Since it is basically the same as the first embodiment, only the differences will be described. In this embodiment, the ribs 19b and the like are provided at the end of the bush 32 to elastically expand the ridges 33 so that the ball valve 21 is loosely fitted in the valve chamber 34. In this case, even if lubricating means is applied to the bush and the ball valve, there is a problem that the ridge 33 is slightly deformed or damaged when the bush is formed or when the ball valve is inserted. A tail plug 29 is crimped to the rear end of the barrel 1.

[0014]

First, FIG. 1 shows a state before writing with the chip 5 facing down, at which time the ball valve 21 comes into contact with the rear end of the ridge 19a and the guide hole 18 is opened. The ink 2 that has entered the valve chamber 15 from the ink storage tube 4 through the conducting hole 18
8 is guided to the back of the tip ball 5a through a groove or the like formed between the ridges. In the embodiment described above, the tip ball 5a is brought into close contact with the inner edge of the tip holding portion by the pressing of the spring 20, thereby preventing the direct current of ink and the drying of the writing tip portion. This configuration is necessary as a refill to be mounted on a writing instrument. However, in the case of the cap type, it is not essential to press the tip ball with a spring.

FIG. 2 shows a state in which the tip 5 is directed upward. At this time, the ball valve 21 is in close contact with the ball receiving seat 14 of the valve chamber 15 and seals the guide hole 18. Even if the ink immediately below 5a runs out, the ink does not flow backward. Therefore, when the chip 5 is turned downward, the ink can immediately flow out, and the writing is prevented from being flared.

[0016]

The configuration and operation of the ballpoint pen according to the present invention are as described above.
In the fine writing, the backflow of ink due to upward writing or impact can be prevented by a ball valve loosely fitted in the valve chamber, and an accident that stains the inside of the shaft cylinder, hands, clothes, and the like is prevented. or,
The ink immediately follows after upward writing or impact, thereby preventing flaring. In addition, the ballpoint pen according to the embodiment has an effect that the writing feel is good because the tip and the base are loosened through the joint.

[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, showing a state in which a chip is directed upward;

FIG. 3 is a longitudinal sectional view showing the entirety of the ballpoint pen according to the first embodiment, showing the first half thereof.

FIG. 4 is a longitudinal sectional view showing the entirety of the ballpoint pen according to the first embodiment, showing the latter half thereof.

FIG. 5 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;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Base 3 Joint 4 Ink storage tube 5 Tip 5a Tip ball 5b Receiving seat 6 Shaft 7 Locking cylinder 7a Flange 8 Rib 9 Step 10 Chip fitting hole 10a Chip fitting hole 10b Holder fitting hole 10c Step portion 11 Holder 12 Fitting tube portion 12a Window portion 13 Bush 14 Ball receiving seat 15 Valve chamber 16 Protrusion 17 Locking portion 18 Guide hole 19 Elastic piece 19a Protrusion 19b Slit 20 Spring 20a Winding portion 20b Straight portion 21 Ball valve 22 Cap 23 Inner cap 24 Clip 25 Vent hole 26 Rib 27 Seal plug 28 Ink 29 Tail plug 30 Follower 31 Follower rod

Claims (3)

[Claims] 1. A tip ball diameter of φ0.
In a ball-point pen having a tip of a small-diameter ball-point pen having a diameter of 3, 0.4 and an ink storage tube in the rear, a bush is provided with a valve chamber at its axis, and a tapered or spherical surface is provided at the rear of the valve chamber. A required number of ridges are provided on the front peripheral wall of the valve chamber, and a ball valve that can be brought into close contact with the ball receiver elastically deforms the ridges and cannot be pulled out into the valve chamber. On the other hand, a shaft portion for crimping the chip is formed at the end of the joint, and the bush is fixed in a tight fit on the axis of the rear inner hole. The storage tube is fitted, and the ink storage tube has low viscosity ink or basically low viscosity but has high viscosity statically and the viscosity decreases by rotation of the tip ball during writing. The ink having the so-called shear thinning property from which the ink flows out is filled, and the ink is discharged. At the end, a follower that follows with the consumption of ink is provided, and when the tip side is upward, the ball valve is in close contact with the ball receiving seat and the conducting hole is sealed, and when the tip side is downward, the sealed state is released. A ball valve is in contact with the rear end of the ridge, and ink is introduced into the chip through a guide hole, a valve chamber, a groove formed between the ridges, and the like. Ballpoint pen. 2. The ballpoint pen according to claim 1, wherein a shaft portion for pressing the chip and a holder fitted on the chip is formed at the end of the joint. 3. The ballpoint pen according to claim 1, wherein a required number of elastic pieces are provided in front of the valve chamber of the bush, and a ridge is formed on an inner surface of the elastic piece.