JP2000335166A - Ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a reverse flow or a direct flow of an ink and to facilitate working accuracy of a chip to stabilize its quality and to reduce a general cost of forming the chip by bringing a tip ball rotatably held by a pressing force of a spring into close contact with an inner edge of a ball holding portion of the chip in a liquidtight manner. SOLUTION: A chip joint 4 made of a resin is fixed to a chip 1 and a holder 2 made of a metal is fixed to a front end of the joint 4. A step portion 5a is formed in an inner hole 7a of a rear end of a shaft 5 rear of the joint 4, and a cutout of a suitable length from a rear end is formed at a predetermined position at the shaft 5. A spring 12 is inserted from the rear end of the shaft 5 into the hole 7a of the chip 1, and a rear end of the spring 12 is removal- inhibited and locked to the portion 5a. The ball 3 rotatably held at the end of the chip 1 by a pressing force of the spring 12 is brought into close contact with an inner edge of a ball holding portion of the chip 1 in a liquidtight manner to prevent the ink from flowing out.

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 tip ball during writing so that the ink flows out. The present invention relates to an improvement of a ball-point pen which is filled with ink.

[0002]

2. Description of the Related Art In general, a ballpoint pen using a water-based ink having a so-called shear-thinning viscosity or a low-viscosity oil-based ink, in which the viscosity is reduced by rotation of a tip ball during writing and the ink flows out, is known. . A ballpoint pen using such an ink has a large amount of ink flowing out (in order to increase the writing density), so that the diameter of the ink storage tube is increased to increase the amount of ink loaded. Further, since the viscosity of the ink is much smaller than that of the oil-based ballpoint pen, the flow resistance to the ink container is small. Accordingly, 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 the 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 on the back surface of the tip ball of the chip runs out when writing upward, there is a danger that the ink and the head will be added directly, causing a remarkable backflow and soiling the hands and clothes. Further, since the viscosity of the ink is low and the amount of outflow is large, there is a problem that the ink is bleeding (direct current) when a gap is formed between the tip ball and the tip holding portion when the tip side is directed downward.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-viscosity ink (an aqueous ink having a shear-thinning viscosity or a low-viscosity ink, in which the viscosity is reduced by the rotation of the tip ball during writing and the ink is discharged). The present invention is an improvement of a ballpoint pen having a relatively large diameter tip ball using an oil-based ink, etc., which satisfies the following performance as required and aims at cost reduction. It is possible to prevent backflow of ink caused by upward writing or impact of a ballpoint pen and direct current when the tip side is placed downward, thereby preventing contamination of the inside of the ball-point pen barrel, hands and clothes. In addition, upward writing, preventing writing scuffing caused by running out of ink due to air entrapment on the back of the tip ball when an impact is applied, and drying caused by imperfect sealing between the tip ball and the inner edge of the tip holding portion. Enables prevention of handwriting. Further, by forming the chip by crimping the holder holding the tip ball and the chip joint, the processing accuracy of the chip is facilitated, the quality is stabilized, and the total cost of chip formation is reduced.

[0004]

The present invention has the following arrangement to achieve the above object. The ballpoint pen according to the first aspect of the present invention has a tip of a ballpoint pen at the tip and an ink storage tube at the rear, and the ink storage tube has low-viscosity ink or statically high viscosity. In a ball-point pen, the viscosity is reduced by the rotation of the tip ball, and the ink flows out, so-called shear-thinning ink is filled, and the rear end of the ink is filled with a grease-like follower that follows with the consumption of the ink. The chip consists of a resin-made tip joint and a metal holder fixed to its front end. A step is formed in the rear end inner hole of the shaft part behind the tip joint, and the shaft part is appropriately longer than the rear end. A notch is formed at the required position, a spring is inserted into the inner hole of the chip from the rear end of the shaft, and the rear end of the spring is locked by the step to prevent the spring from coming off. Pressing force Rotatably embraced by a tip ball-flop tip is configured to be in close contact with the liquid-tight form the inner edge of the ball holding portion of the chip outflow of ink is prevented.

According to a second aspect of the present invention, there is provided a ball-point pen according to the first aspect, wherein the spring has a rod shaft portion at its tip, and a pressing force applied rearward from a rear end of the rod shaft portion. , And a closely wound end winding portion is provided behind the winding portion.

According to a third aspect of the present invention, there is provided a ball-point pen according to the first aspect, wherein the spring is provided with a tightly wound end winding portion behind a winding portion for applying a pressing force. At the front end of the winding portion, there is provided a push rod provided with a rod shaft portion in contact with the back surface of the tip ball and a groove portion capable of guiding ink behind the rod shaft portion.

[0007]

1 and 3 show an embodiment of the present invention. First, as shown in the figure, a rear shaft portion 9 fixed to the inner writing portion side of an ink container tube 11 filled with ink 13 inside a tube made of a polypropylene resin and an inner hole to which the tip 1 is press-fitted and fixed. A joint 6 having a tapered or spherical valve element receiving seat 7c having a guide hole 7d substantially at the center of the inside thereof is provided in the joint 6, and a valve formed by the axial rear end of the chip and the valve element receiving seat 7c. A ball-shaped valve element 10 loosely fitted in the chamber 7b provides a structure for communicating from the ink storage tube 11 to the tip ball 3 serving as a writing portion during normal writing. A ball-point pen having a structure in which backflow of ink is prevented by being in close contact with the valve body receiving seat 7c, and the ball-point pen is mounted on a cap-type or a cap-off knock-type writing instrument and is used as a so-called ball-point pen. Shows the refill form. Although the above-described valve body 10 is shown in a ball shape, the valve body is formed in a shaft shape and both end faces are formed in a tapered shape or a spherical shape, and a groove for guiding ink is formed on a side surface as necessary. It is also possible to configure.

In this ball-point pen, the ink 13 has a statically high viscosity, and the viscosity of the ink decreases due to the rotation of the tip ball 3 during writing, so that the ink 13 has a shear thinning viscosity so that the ink flows out smoothly. A grease-like follower 14 for preventing the ink from volatilizing and preventing the ink from flowing out is filled with a water-based or oil-based ink (commonly referred to as a medium viscosity ink) or a low-viscosity oil-based ink. And a follower rod 15 for improving stability over time and drop resistance.

FIG. 2 shows another ballpoint pen configuration of the above embodiment. The difference from the above-described embodiment is that the tip 1 is directly fixed to the ink storage tube 16 without a joint, and the rear end of the ink 13 is filled only with the grease-like follower 14. This form of ballpoint pen is mainly used as a ballpoint pen refill to be mounted on double-type writing instruments, etc.
Since the ink storage tube is thin, even if there is no valve body for preventing the backflow of the ink, practical backflow of the ink is prevented. (still,
There is no need for follower rods. )

FIG. 3 is an enlarged view of a ball-point pen tip 1 according to an embodiment of the present invention. The chip 1 is composed of a resin-made chip joint 4 and a metal holder 2 at the end thereof.
Is fixed, a step 5b is formed in the rear end bore of the shaft 5 behind the tip joint 4, and a notch 5a of an appropriate length from the rear end is formed in the shaft 5 at the required position. I have.
Further, the tip ball 3 as a writing portion is loosely fitted by having a channel for securing ink conduction with a ball holding portion 2b formed by caulking or the like and having a receiving seat surface 2c for receiving the tip ball 3. is there. Also, the spring 12 is inserted into the inner hole of the chip from the rear end of the shaft (the shaft 5 is appropriately expanded by the notch 5a).
The rear end of the tip 5 is retained and locked by the step 5b, and the tip of the rod 12a at the tip of the spring 12 presses the back surface of the tip ball 3 and is rotatably held by the tip of the tip. The tip ball 3 is configured so as to be in close contact with the inner edge of the ball holding portion 2b of the chip in a liquid-tight manner, so that outflow and drying of the ink are prevented.

FIG. 4 shows another embodiment of the chip. The spring 19 has a winding portion 1 for applying a pressing force.
A tightly wound end winding portion 19b is provided behind 9a, and a small-diameter rod shaft portion 18a that comes into contact with the back surface of the tip ball 3 at the front end of the winding portion 19a and ink can be guided behind the rod shaft portion. A pressing body 18 having a simple groove 18b is provided.

[0012]

FIG. 1 shows a state before writing with the chip 1 facing down, at which time the valve body 10 comes into contact with the rear end of the chip 1 to open the guide hole 7d. A cutout portion 5a is provided at the rear end of the tip 1 at a required position, and the ink 13 that has entered the valve chamber 7b from the ink storage tube 11 through the guide hole 7d is guided to the back surface of the tip ball 3. In this state, the tip ball 3 is brought into close contact with the inner edge of the ball holding portion 2b of the chip by the pressing of the rod shaft portion 12a of the spring 12, so that the direct current of the ink is prevented. In addition, the tip ball 3 is slightly retracted by the writing pressure, so that a gap is generated and ink can flow out. By writing, the viscosity of the tip ball 3 decreases due to the rotation of the tip ball 3 and ink flows out. Becomes possible.

On the back of the tip ball 3, a receiving seat surface 2c is provided.
There is a (reception seat for a tip ball having a plurality of ink inflow grooves penetrating toward the chip inner hole), and the tip of the rod portion 12a penetrates through the center hole 2d of the reception seat surface 2c. The ink in the chip 1 is filled with the ink inflow groove and the center hole 2d and the rod shaft portion 1.
The ball 3 is guided to the back of the tip ball 3 through a gap between the ball 2a and the ball 2a.

When the chip 1 is directed upward, the valve body 10 is in close contact with the valve body receiving seat 7c of the valve chamber 7b and the guide hole 7d
Is sealed, so that ink does not flow backward even when the ink on the back surface of the tip ball 3 is exhausted by upward writing. Therefore, when the chip 1 is turned downward, the ink can immediately flow out, and writing is prevented from being rubbed. (By the way, in the structure without the valve element, the ink acts in the backward flow direction in the upward writing, so that air is trapped in the chip, and the ink does not immediately follow in the downward writing, resulting in sharpening. Entanglement is accumulated.)

Further, since the tip ball 3 is always in close contact with the inner edge of the tip holding portion, the dryness of the tip portion prevents writing blur. Further, even if upward writing or impact is applied by the cooperative action of the distal end ball 3 and the valve element 10, air entrainment is prevented, so that writing blur is prevented.

However, in the ball-point pen configuration shown in FIG. 2 as described above, since the ink containing tube 16 is thin, even if there is no valve body for preventing the backflow of ink, practical backflow of ink is prevented. Also, there is no need for a follower bar.

[0017]

The configuration and operation of the ballpoint pen according to the present invention are as described above. Since the tip ball is in close contact with the inner edge of the chip holding portion except when writing, the direct current or backflow of ink is prevented and the inside of the shaft cylinder is prevented. Accidents that stain hands, clothes, etc. are prevented. or,
Writing scratches due to drying are also prevented. In addition, by providing a valve element that fits loosely in the valve chamber, a state of incomplete close contact between the tip ball and the tip holding portion and a state of severe ink backflow due to upward writing or impact are guaranteed. Further, by forming the chip by crimping the holder holding the tip ball and the chip joint, the processing accuracy of the chip is facilitated, the quality is stabilized, and the total cost of chip formation can be reduced. .

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a ballpoint pen according to an embodiment of the present invention, showing a state in which a chip is directed downward.

FIG. 2 is a longitudinal sectional view showing another embodiment of the ballpoint pen according to the embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a chip.

FIG. 4 is a sectional view showing another embodiment of the chip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chip 2 Holder 2a Shaft part 2b Ball holding part 2c Receiving seat surface 2d Center hole 3 Tip ball 4 Chip joint 5 Shaft part 5a Notch 5b Step 6 Joint 7 Front shaft part 7a Inner hole 7b Valve chamber 7c Valve body receiver Seat 7d Guide hole 8 Flange 9 Rear shaft 10 Valve body 11 Ink storage tube 12 Spring 12a Bar shaft 12b Winding unit 12c Counter winding 13 Ink 14 Follower 15 Follower bar 16 Ink storage tube 17 Tip 18 Push body 18a Rod shaft Part 18b Groove part 19 Spring 19a Winding part 19b End turn part

Claims (3)

[Claims] 1. A tip of a ball-point pen at the tip and an ink storage tube at the rear. The ink storage tube has a low viscosity ink or a static high viscosity. In a ball-point pen having a so-called shear-thinning ink from which the ink flows out and a grease-like follower that fills the rear end of the ink with the consumption of the ink, the tip is made of resin. A metal holder is fixed to the joint and its front end, a step is formed in the inner hole of the rear end of the shaft behind the tip joint, and a notch of an appropriate length from the rear end is formed in the shaft. The spring is inserted into the inner hole of the chip from the rear end of the shaft portion, and the rear end of the spring is locked and stopped by the step portion,
The tip of the tip, which is rotatably held at the tip of the tip by the pressure of the spring, is in liquid-tight contact with the inner edge of the ball holding portion of the tip, so that ink is prevented from flowing out. Characteristic ballpoint pen. 2. The spring has a rod shaft portion at its tip, a winding portion for applying a pressing force rearward from the rear end of the rod shaft portion, and a tightly wound end winding portion behind the winding portion. The ballpoint pen according to claim 1, wherein the ballpoint pen is provided. 3. The spring is provided with a tightly wound end winding portion provided behind a winding portion for applying a pressing force, and a rod shaft portion contacting the back surface of a tip ball at a front end of the winding portion, and the rod shaft portion. The ballpoint pen according to claim 1, further comprising a pressing body provided with a groove capable of guiding ink at a rear side of the ballpoint pen.