JPH10100580A - Ballpoint pen - Google Patents

Abstract

(57) [Summary] [Object] To enable efficient writing of an ink amount and a follower amount so that writing can be performed until the remaining amount of ink becomes invisible, and that a backflow of the ink rear end portion can be prevented. A so-called so-called ink is provided in which the tip of a barrel is provided with a ball-point pen tip, the inner hole of the barrel has a high viscosity statically, and the viscosity decreases by rotation of the tip ball during writing to cause ink to flow out. A water-based ink or an oil-based low-viscosity ink having a shear thinning property and a grease-like follower that fills the rear end of the ink with the consumption of the ink are further filled, and a resin made of a resin having a specific gravity substantially equal to that of the follower is further filled in the follower. In a ball-point pen having a follower rod immersed therein, the barrel is a resin molded product in which a front shaft portion in which a tip is fixed in front and a large ink container tube in which ink is filled in the rear portion. A rib having an inclined surface in the axial direction is formed at a required position of the inner peripheral wall at the front end of the ink storage tube, and the follower rod is guided by the inclined surface of the rib to advance, and the inner peripheral wall on the opposite side to the rib is formed. Forward stops when almost touching At the same time, only the follower can flow into the inner bore of the front shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved ballpoint pen having a mechanism for preventing ink from flowing back.

[0002]

2. Description of the Related Art As an intermediate between an oil-based ball-point pen and an aqueous ball-point pen, it has a high viscosity statically, and has a so-called shear thinning viscosity in which the viscosity is reduced by rotation of the tip ball during writing and ink is discharged. Ballpoint pens using aqueous inks (referred to as neutral or medium viscosity ballpoint pens) are known. However, ballpoint pens that use ink with shear thinning properties tend to evaporate ink and have a large amount of ink flowing out (in order to increase the writing density). doing. Further, since the viscosity of the ink is smaller than that of a normal oil-based ballpoint pen, the flow resistance to the ink container is small. Therefore,
Ink leaks easily (ink flows backward at the rear end of the ink storage tube) due to the weight and impact of the ink. On the other hand, the low-viscosity oil-based ink suppresses evaporation of the ink, but still causes a backflow phenomenon. For this reason, normally, the ink is prevented from evaporating at the rear end of the ink, and moves following the consumption of the ink during writing. A follower is provided. However, even when the follower is provided, when writing upward, if the ink on the back surface of the tip ball runs out, a significant backflow occurs because the ink head is added directly. or,
If the inner diameter and length of the ink storage tube are increased to increase the amount of ink to be filled, there is a problem that the backflow phenomenon due to impact cannot be supported. In addition, when the backflow occurs, there is a risk that the inside of the shaft cylinder is soiled and ink leaks from the air holes provided in the shaft cylinder to stain hands and clothes. The ink backflow phenomenon also occurs with a normal oil-based ballpoint pen, but a ballpoint pen using medium-viscosity ink or oil-based ink occurs significantly.

[0003] In a general ball-point pen, a gap for allowing ink necessary for writing to flow out is appropriately provided around a ball which is a writing portion. Therefore, the ink evaporates from the gaps, vibrates during transportation, falls, ink oxidative deterioration due to long-term storage, ink leaks (DC), fuzziness due to air entry, and long-term writing with a pen stand at the store. Save the part upward in the axial direction (hereinafter "upward")
Accidents such as ink backflow, in which the ink drops rearward in the axial direction, are often seen. Conventionally, in order to solve these problems, a spring is provided inside a tip which can be seen with a writing instrument type correction fluid or the like, and measures have been taken in Japanese Utility Model Laid-Open Nos. 55-172104 and 57-1935.
No. 78 is known.

A follower is provided at the rear end of the ink in order to prevent the backflow of the rear end of the ink. However, when the ink storage tube has a large diameter, the follower itself has fluidity, so that a temperature change or a drop may occur. There is a danger that the rear end of the follower will be deformed by the impact and induce backflow. Therefore, the follower rod is immersed in the follower to prevent deformation of the follower. Further, in order for the follower and the follower rod to move together, it is desirable that the follower and the follower rod have substantially the same specific gravity and that the follower rod is immersed in the follower. In addition, since the follower adheres to the inner wall of the ink storage tube as it advances, the amount of the follower in front of the follower rod is consumed. The follower amount can be increased accordingly, but the ink amount decreases and the appearance is poor. or,
If the flow path of the follower to the inner hole of the front shaft portion becomes small at the most advanced position of the follower rod, there is a problem that the follower before and after the follower rod is divided. In this state, if there is almost no follower at the rear end of the ink, there is a problem that writing is impossible even though the remaining amount of the ink is visible after impact or upward writing.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a ballpoint pen using an aqueous medium-viscosity ink or a low-viscosity oil-based ink, which allows efficient filling of the ink amount and the follower amount to reduce the remaining ink amount. Writable until invisible,
In addition, another object of the present invention is to improve a ballpoint pen capable of preventing ink from flowing backward due to upward writing or impact.

[0006]

The ball-point pen of the present invention has a tip of a ball-point pen at the tip of the barrel, and has a high viscosity in the inner hole of the barrel so that the tip of the ball rotates during writing. A water-based or oil-based low-viscosity ink having a so-called shear thinning property in which the viscosity is reduced and the ink flows out, and a grease-like follower that fills the trailing end of the ink with consumption of the ink is filled, and the follower is further filled in the follower. In a ballpoint pen in which a resin-made follower rod having a specific gravity substantially equal to that of a follower is immersed, the barrel has a front shaft portion to which a tip is fixed in front, and a large size in which ink is filled in the rear portion. Is formed of an integral resin molded product, a rib having an inclined surface in the axial direction is formed at a required position on the inner peripheral wall at the front end of the ink container tube, and the follower rod is guided by the inclined surface of the rib. And move forward with the ribs It allows inflow follower only front barrel portion hole with advanced when substantially contact with the inner peripheral wall of the contralateral is prevented.

A valve chamber is provided in the front shaft portion so as to face the rear end of the chip, and a tapered or spherical ball receiving seat and a guide hole are provided in the rear end, and the ball valve is loosely fitted in the valve chamber. The guide hole communicates with the inner hole of the ink storage tube. Also, a spring is built into the chip, and the tip of the straight portion presses against the back surface of the tip ball in a pressing manner so that the tip ball is in close contact with the ball holding portion of the tip and the rear end of the winding portion is the tip rear end. It is made impossible to extract from.

[0008]

1 to 3 show a first embodiment of the present invention. First, as shown in FIG.
And a large-diameter ink storage tube 10 to be filled with ink at the rear of the shaft portion 5 formed by integral polypropylene resin molding. The ink storage tube is not limited to a cylindrical shape, but may be formed in a cylindrical body having an irregular cross section. Further, a rib 10a having an axially inclined surface 10b is formed at a required position on the inner peripheral wall of the front end of the ink storage tube 10, and a follower rod 13 described later is guided by the inclined surface 10b of the rib 10a to advance and move forward. When the inner peripheral wall is substantially in contact with the inner peripheral wall opposite to 10a, the forward movement is prevented and only the grease-like follower 12 can flow into the inner bore of the front shaft portion.

A shaft portion 1a of a tip 1 holding a tip ball 2 serving as a writing portion is crimped to an inner hole 5d in front of the shaft cylinder 4, and a valve chamber is provided in an inner hole 5d facing the rear end of the tip 1. 6, a ball receiving seat 5a having a tapered or spherical shape and a guide hole 7 are provided at the rear end thereof. A ball valve 8 is loosely fitted into the valve chamber 6, and the guide hole 7 is connected to the ink containing tube 10a. A portion 5c protruding rearward of the shaft at a required location on the periphery of the valve chamber 6 is provided. When the chip 1 is pressed into the inner hole 5d, the rear end of the shaft portion 1a has a portion 5c. 5c by pressing against
Is bent to the axial center side to form a contact portion on the front side of the ball valve 8.

In writing, a ball-point pen having a structure in which the ink reservoir tube 10 communicates with the tip ball 2 serving as a writing portion and a ball valve 8 having a structure in which the ball valve 8 is in close contact with the ball receiving seat 5a to prevent backflow of ink when facing upward. The ballpoint pen is a so-called ballpoint pen refill which is usually used by being inserted into a shaft cylinder (not shown) serving as a writing shaft.

In this ball-point pen, the ink 11 has a statically high viscosity, and the viscosity of the ink decreases due to the rotation of the tip ball 2 at the time of writing, and the ink 11 has a shear thinning viscosity so that the ink flows out smoothly. An aqueous medium-viscosity ink or a low-viscosity oil-based ink is filled, and a follower 12 for preventing the ink from volatilizing and preventing the ink from flowing out is provided on the rear side in the axial direction of the ink storage tube 10. A follower bar 13 is provided. A tail plug 14 having a vent hole 14a is fixed to the rear end of the ink storage tube 10.

The ballpoint pen of the embodiment has a tip ball 2
The spring 3 is built in the chip so as to press the spring. First, a straight portion 3a that abuts on the back surface of the tip ball 2 is provided at the writing portion side tip of the spring 3, and a winding portion 3b is provided from the straight portion rear end toward the rear end. The rear end of the shaft portion 1a of the chip is caulked so that it cannot be pulled out. (Caulking part 1e)

FIG. 4 shows a second embodiment of the present invention. The second embodiment has the same basic configuration as the first embodiment, and only different points will be described below. First, the tip shaft 2
The shaft portion 1a of the chip 1 is press-bonded to one inner hole 22, and a valve chamber 23 is provided at the rear end of the inner hole 22 so as to face the rear end of the chip. A conical ball seat 2 is provided at the rear of the valve chamber 23.
4 are formed. The valve chamber 23 is formed so as to be appropriately eccentric with respect to the axis of the chip 1, and a groove 24a is formed on one side of the inner wall of the valve chamber. In addition, a guide hole 25 is formed behind the ball receiving seat 24 so as to communicate with the ink storage tube 27.
A ball valve 26 is loosely fitted in the valve chamber.

FIG. 5 shows a third embodiment of the present invention. The third embodiment has the same basic configuration as the first embodiment, and only different points will be described below. The tip 33 is a holder 3 holding a tip ball 35 serving as a writing portion at the tip.
The tip joint 36 is crimped to the holder 4 and the holder 34, and the rear end of the spring 40 is inserted into the tip joint in an abutting state, and a straight portion 40 a abutting on the back surface of the tip ball 35 is provided at the tip of the spring 40. A winding portion 40b is provided rearward from the rear end of the straight portion, and a bent end portion 40c is provided at the rear end of the winding portion 40b toward the center. A valve chamber 38 is provided at the rear, and a tapered or spherical ball receiving seat 38a and a guide hole 38c are provided at the rear end of the valve chamber 38, and the bent end 40c and the ball receiving seat 3 are provided.
8a, the ball valve 39 is loosely fitted, and the guide hole 38c is provided in communication with the rear end opening of the tip joint 36,
The tip 33 configured as described above is fixed to the tip of the tip shaft portion 31 to form a ballpoint pen. A rib 38b is provided at a required location on the inner wall of the front portion of the ball receiving seat 38a, and a front end of the rib 38b serves as a contact portion of a rear end of the spring 40.

[0015]

The first embodiment will be described. First, when the tip 1 is crimped to the tip shaft 5 of the barrel 4, the tip 1
The rear end of a is pressed against the piece 5c, and the piece 5c is bent toward the axial center to form a reliable contact portion on the front side of the ball valve 8.
Further, the ink is supplied to the tip ball 2 through the space between the pieces. It is to be noted that the required ink outflow amount can be set by changing the width dimension and the required number of the pieces 5c.

The tip ball 2 serving as a writing portion has a spherical shape. When the tip ball 2 is pressed from behind by a spring 3 by the ball holding portion 1b of the chip 1, the valve is closed. By shutting off the outside air from the inside of the ballpoint pen, it prevents dry-up due to ink volatilization, impacts, prevents air from entering by dropping, prevents ink from leaking out, and prevents ink deterioration near the pen tip due to air. You can expect it. The writing pressure required for writing at the time of writing varies depending on the type of ballpoint pen, but generally ranges from 50 g to 500 g. In the embodiment, since the pressing force of the spring 3 for pressing the tip ball 2 is set to 2 g to 100 g, preferably 5 g to 20 g, at the time of actual writing, the tip ball 3 and the ball holding portion 1 b
In this state, the valve mechanism is in an expanded state, and ink flows out like a normal ball-point pen, and writing is possible. Also, at the moment when the writing is completed and the ballpoint pen is released from the paper, the valve of the writing part is instantly closed by the force of the spring, and the dry-up resistance, impact resistance, air penetration resistance, ink leakage prevention again Performance is demonstrated.

A ball valve and a shaft coupling having a valve structure which can prevent air entrapment and backflow of ink when writing upward are used to move ink by upwardly contacting the ball valve with the valve chamber. However, by using the valve mechanism in the writing section to prevent air entrapment and ink movement when not pointing upwards and not writing, the safety is further improved, especially when ink is transferred. A so-called medium-viscosity ballpoint pen using a shear-thinning ink that is easy to perform effectively improves the performance of the backflow prevention mechanism.

Further, when the grease-like follower 12 and the follower rod 13 reach the vicinity of the front end of the ink container 10 due to the consumption of the ink 11 accompanying the writing, the follower rod 13
0a is guided and guided by the inclined surface 10b, and when the rib 10a substantially contacts the inner peripheral wall opposite to the rib 10a, the advance is prevented and the follower 12 located behind the follower rod 13 is passed through the space secured at the front end. Since it flows into the inner hole of the front shaft portion, an appropriate amount of follower can be present at the rear end of the ink with an efficient follower amount. In this state, even if the user writes upward, the ink head is very small, so that the backflow problem does not occur even if the follower rod 13 does not act.

Next, in a second embodiment, FIG. 4 shows a writing state in which the tip 1 is turned downward.
Abuts against the rear end of the chip 1 on one side, and the ink that has entered the valve chamber 23 through the guide hole 25 passes by the ball valve 26, passes through the groove 24 a, and is guided to the tip ball 2. You. In a state where the chip 1 is turned upward (not shown), the ball valve 26 is in close contact with the ball receiving seat 24 of the valve chamber 23 and seals the guide hole 25. Even if the ink disappears, the ink does not flow over the head and does not flow backward.

In the third embodiment, since the chip 33 is formed by pressing the holder 34 to the chip joint 36, the processing accuracy of the chip is increased and the quality is improved. Also, the productivity is good. In addition, since the ink backflow prevention mechanism is housed in the tip 33, the outer dimensions of the tip of a general oil-based ballpoint pen that does not require the ink backflow prevention mechanism are made the same, and the shaft joint and the ink storage tube are shared. It is possible to improve productivity. The operation of this embodiment is basically the same as that of the above-described embodiment, and a description thereof will be omitted.

[0021]

The structure and operation of the ballpoint pen of the present invention are as described above. In a ballpoint pen using an aqueous medium-viscosity ink or a low-viscosity oil-based ink, efficient filling of the ink amount and the follower amount is achieved. Then, writing can be performed until the remaining amount of ink becomes invisible, and at the same time, backflow of ink caused by upward writing or impact can be prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the entirety of a ballpoint pen according to a first embodiment of the present invention, showing a state in which a follower bar is most advanced.

FIG. 2 is a longitudinal sectional view of the whole ballpoint pen showing an initial position state of a follower bar in the first embodiment.

FIG. 3 is an enlarged sectional view of a front part in the first embodiment.

FIG. 4 is an enlarged sectional view of a front portion of a ballpoint pen according to a second embodiment.

FIG. 5 is an enlarged sectional view of a front portion of a ballpoint pen according to a third embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 chip 1a shaft portion 1b ball holding portion 1c receiving seat 1d center hole 1e swaging portion 2 tip ball 3 spring 3a straight portion 3b winding portion 4 shaft cylinder 5 front shaft portion 5a ball receiving seat 5b rear end portion 5c piece portion 5d inside Hole 6 Valve chamber 7 Guide hole 8 Ball valve 9 Step 10 Ink storage tube 10a Rib 10b Inclined surface 11 Ink 12 Follower 13 Follower rod 14 Tail plug 14a Vent hole 20 Shaft tube 21 Front shaft portion 22 Inner hole 23 Valve chamber 24 Ball Receiving seat 24a Groove portion 25 Guide hole 26 Ball valve 27 Ink storage tube 27a Rib 30 Shaft tube 31 Front shaft portion 32 Inner hole 33 Chip 34 Holder 34a Shaft portion 35 Tip ball 36 Chip joint 36a Inner hole 37 Shaft portion 38 Valve chamber 38a Ball Receiving seat 38b Rib 38c Guide hole 39 Ball valve 40 Spring 40a Straight part 40b Winding part 40c Bending end 41 Rib

Claims (3)

[Claims] 1. A tip of a barrel is provided with a tip of a ballpoint pen, and an inner hole of the barrel has a statically high viscosity, and the viscosity is reduced by rotation of the tip ball during writing, so that ink is discharged. A water-based or oil-based low-viscosity ink having a so-called shear-thinning viscosity and a grease-like follower that fills the rear end of the ink with the consumption of the ink, and further has a resin having a specific gravity substantially equivalent to the follower in the follower. In a ballpoint pen formed by dipping a follower rod made of a resin, the barrel is formed by resin molding in which a front shaft portion to which a tip is fixed in front and a large ink container tube in which ink is filled in the rear portion. Formed of goods,
A rib having an inclined surface in the axial direction is formed at a required position on the inner peripheral wall at the front end of the ink storage tube, and the follower rod is guided by the inclined surface of the rib and moves forward to substantially contact the inner peripheral wall opposite to the rib. The ballpoint pen is characterized in that, when the ballpoint pen is moved forward, only the follower can flow into the inner hole of the front shaft portion. 2. A valve chamber is provided in the front shaft portion so as to face the rear end of the chip, and a tapered or spherical ball receiving seat and a guide hole are provided at the rear end, and the ball valve is loosely fitted in the valve chamber. 2. The ballpoint pen according to claim 1, wherein the guide hole is provided so as to communicate with an inner hole of the ink storage tube. 3. A spring is incorporated in the chip, and the tip of the straight portion presses against the back surface of the tip ball so that the tip ball comes into close contact with the ball holding portion of the tip. 3. The ballpoint pen according to claim 1, wherein the ballpoint pen cannot be pulled out from the rear end of the chip.