JP2000225794A - Ballpoint pen refill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a backflow preventing mechanism of an ink not disturbed at flowability of the ink even when a large filler exists in the ink. SOLUTION: A necked part 4f of an overall peripheral state is formed on an outer periphery of a rear shaft of a joint 2 press bonded to an ink containing tube 10, and tapered parts are formed on front and rear inner surfaces of a guide hole at the inner surface of the neck part 4f. The front tapered part is used as a ball receiving seat, and a rib 4c is further formed on the front inner surface, and a valve chamber 4a is formed between the seat 4b and the rib. A ball valve 8 presses the rear tapered part 4e from a rear end of the rear shaft 4 of the joint to elastically deform the necked part in an enlarging direction so that the valve is loosely engaged within the chamber. When a tip is upward, the valve is brought into close contact with the seat to liquidtightly close the guide hole. A low density ink such as an aqueous or low density oily ink or the like having a so-called shear-rate thinning characteristics is filled in the tube 10. A grease-like follower following the ink as the ink is consumed is arranged at an rear end of the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen refill filled with low-viscosity ink or a ballpoint pen refill having a large-diameter ink storage tube.

[0002]

2. Description of the Related Art The ink of a conventionally known oil-based ballpoint pen has a high viscosity, and a small amount of ink flows out by rotation of a tip ball during writing. In addition, there are problems such as unevenness, unevenness of writing lines, low density, and high writing pressure. In addition, as an improvement of the conventional oil-based ballpoint pen, a relatively low-viscosity ink is used. Are known. However, since this ink has a drawback that the ink easily dries, a cap for sealing the writing tip is required. Therefore, a low-viscosity oil-based ink with excellent drying resistance is conceivable. However, the amount of the ink flowing out is also large, and in order to extend the writing life, the diameter of the ink storage tube is increased to increase the amount of ink loaded. . The same applies to the water-based ink. However, since the viscosity of the ink is smaller than that of the conventional oil-based ballpoint pen ink, the flow resistance to the ink storage tube 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 at the time of 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 side of the tip ball runs out when writing upward, there is a danger that the ink or the head will be added directly, causing a remarkable backflow and soiling the hands and clothes. Therefore, a follower is provided at the rear end of the ink with the chip facing upward, and a ball valve for closing a hole for introducing the ink to the chip is provided in front of the ink.

In addition, ballpoint pens include fillers such as metals in the ink so that the drawn lines have metallic luster, or are applied to correct erroneous characters. Various inks have been developed that simply cannot be classified with low and high viscosities, such as those that require prevention and those that contain rubber latex in the ink so that what is written can be erased with an eraser etc. I have. Also, ballpoint pens using these inks are writing instruments which generally have a large amount of ink flowing out, and therefore have a problem that the ink storage tube is thick and the ink flows backward. On the other hand, there is a problem that the flow of the ink is easily hindered.

As a conventional example, FIG. 2 shows a backflow prevention mechanism for ink in which a tip of a ballpoint pen is crimped to the end of a joint, an ink storage tube is fixed to a rear end, and a ball valve is loosely fitted in an inner hole of the joint. A ballpoint pen refill 14 is shown. 3 and 4 show an example in which a conventional ballpoint pen refill is mounted on a writing implement composed of a barrel and a cap. (Note that the ballpoint pen refill of the embodiment described later can be mounted similarly, and the ballpoint pen refill of the embodiment can be mounted on a cap-off writing instrument.) As shown in FIG. A front shaft portion 15a having an inclined rib formed at a required portion in the first half is provided, a ring-shaped flange portion is formed at the rear end of the rib, and a rear shaft portion 15 is formed in the second half.
b is provided, and the ink storage tube 1 is provided on the rear shaft portion 15b.
0 is fixed. A tip 16 holding a tip ball 17 is pressed into a tip hole of the front shaft portion 15a.

The joint 15 is integrally formed of a synthetic resin which can be elastically deformed in the same color as the ink color, and is provided with a valve chamber 15c at the rear in communication with the front end hole of the front shaft portion 15a. A conical ball seat is provided at the rear of the valve chamber 15c. Also, the valve chamber 15c is appropriately eccentric with respect to the axis of the tip hole, that is, the axis of the press-fitting shaft portion of the tip, while the valve chamber 15c is fitted in the inner periphery of the tip hole. The ball valve 19 is loosely fitted in the valve chamber. In addition, a guide hole that connects the ball receiving seat and the ink storage portion is formed behind the valve chamber.

A cylindrical ink storage tube 10 is press-fitted and fixed to the outer periphery of the rear shaft portion 15b of the joint 15 with its leading end abutting on the rear end of the flange portion of the joint. It communicates with the guide hole of the joint. An ink 11 having a low viscosity or an ink 11 having a low viscosity or a high viscosity in a static state, and having a viscosity reduced by rotation of the tip ball during writing and having a shearing viscosity allowing the ink to flow out is provided in the ink storage tube 10. Filled,
Furthermore, while preventing evaporation of the ink at the rear end of the ink,
A transparent or translucent grease-like follower 12, which is movable in contact with and following the ink surface as the ink is consumed, is filled. A follower rod 13 having a specific gravity substantially equal to that of the follower 12 is immersed in the follower 12.

In the ball-point pen refill 14 configured as described above, the gap formed when the ball valve 19 is abutted in a state where the ball valve 19 is eccentric to the rear end of the chip in the downward direction of the chip is an inflow port of ink to the chip. It is a small gap. Therefore, there is a problem in that the size of the inlet is reduced due to variations in the dimensions of the members, and when there is a coarse filler in the ink like the above-described ink, the filler agglomerates at the inlet and the fluidity of the ink is hindered. .

[0009]

The ballpoint pen according to the present invention has a spring for pressing the tip of the ball into the inner hole of the joint by pressing the tip of the ballpoint pen on the tip of the joint, fixing the ink storage tube at the rear end. In a ball-point pen refill with a built-in and ink backflow prevention mechanism that loosely fits a ball valve, it is possible to provide an ink backflow prevention mechanism that does not impede the fluidity of the ink even if there is a coarse filler in the ink. And Further, the joint for loosely fitting the ball valve is formed of an integral resin molded product, so that the ball valve can be easily inserted.
It is an object of the present invention to make it possible to incorporate members from one direction and to provide them at low cost.

[0010]

The present invention has the following arrangement to solve the above-mentioned problems. The ballpoint pen refill according to the first aspect of the present invention is characterized in that a tip of a thin tubular ballpoint pen is pressure-bonded to a tip of a resin joint, an ink storage tube is fixed to a rear end, and a tip ball is inserted into an inner hole of the joint. In a ball-point pen refill with a built-in spring for pressing and a backflow prevention mechanism for ink that loosely fits a ball valve, an all-round concave portion is formed on the outer periphery of the rear shaft portion of the joint that presses against the ink storage tube. A tapered portion is formed on the front and rear inner surfaces with the inner surface as a guide hole, a required taper is formed on the front inner surface with the front tapered portion as a ball receiving seat, and a valve chamber is formed between the ball receiving seat and the rib. Is formed,
When the ball valve presses the rear tapered portion from the rear end of the rear shaft portion of the joint to elastically deform the concave portion in the expanding direction, the ball valve is loosely fitted in the valve chamber, and when the tip is upward. The ball valve is configured so as to be in close contact with the ball receiving seat so that the guide hole is closed in a liquid-tight manner, and the ink storage tube has a low viscosity such as aqueous or low-viscosity oil-based ink having a so-called shear thinning property. The ink is filled, and a grease-like follower is provided at the rear end of the ink so as to follow the ink as the ink is consumed.

[0011]

FIG. 1 shows a ballpoint pen refill 1 according to an embodiment of the present invention. As shown in the figure, the joint 2 is provided with a front shaft portion 3 in which an inclined rib is formed at a required portion in a front half, a ring-shaped flange portion 5 at a rear end of the rib, and a rear half in a rear half. A shaft portion 4 is provided, and an ink storage tube 10 is fixed to the rear shaft portion 4. A thin tubular tip 6 holding a tip ball 7 is pressed into the tip hole 3a of the front shaft portion 3 with its rear end in contact with the step 3c. A slightly enlarged rear hole 3b is provided behind the step portion 3c, and a ridge 3d is provided behind the rear hole.

Further, an entire circumferential concave portion 4f is formed on a rear outer peripheral portion of the rear shaft portion 4, and a rear end portion 4d is further formed behind the concave portion 4f. The rear shaft portion 4 is pressed against the ink storage tube 10, and the outer peripheral dimension of the rear end 4 d is set slightly smaller than the inner peripheral dimension of the ink storage tube 10. In addition, the crevice part 4
f is formed as a guide hole 4g, a tapered portion is formed on the front and rear inner surfaces thereof, a front tapered portion is formed as a ball receiving seat 4b, and a rib 4c is formed on the front inner surface of the ball receiving seat 4b. Is formed as a valve chamber 4a. The protruding ridge 3d is located in front of the rib 4c.

On the other hand, the spring 9 has a straight portion 9a at the front and a winding 9b at the rear. The spring 9 is inserted from the rear end of the rear end 4 d of the joint 2, the rear end of the winding part 9 b contacts the front end of the ridge 2 h and is prevented from falling off, and the front end of the straight part 9 a faces the back of the tip ball 7. When pressed, the tip ball 7 comes into liquid-tight contact with the inner surface of the ball holding portion 6a of the chip.

Thus, in the case of a low-viscosity ink or an ink that is easy to dry, it is possible to prevent direct current (dropping) of the ink and ink clogging of the tip ball portion. The pressing force of the spring differs depending on the tip ball diameter and the type of ink. However, a low-viscosity ballpoint pen with a tip ball diameter of about 0.5 mm is about 5 to 20 grams, and a correction tool type with a large tip ball diameter is 20 to It is set in the range of about 300 grams.

Since the outer peripheral dimension of the rear end 4d of the joint 2 is set slightly smaller than the inner peripheral dimension of the ink storage tube 10, the ball valve 8 is tapered rearward from the rear end of the rear end 4d. By pressing the portion 4e, the front and rear tapered portions are easily bent and deformed while the rear end portion 4d slides, so that the crevice portion 4f is elastically deformed in the expanding direction and the ball valve 8 moves into the valve chamber 4a. At the same time, when the tip 6 faces upward, the ball valve 8 comes into close contact with the ball receiving seat 4b, so that the guide hole 4g can be closed in a liquid-tight manner. In addition, although the ball valve 8 is shown as a sphere in the embodiment, a rod-shaped body may be used as an equivalent means.

In addition, low viscosity inks such as water-based or low-viscosity oil-based inks having a so-called shear-thinning viscosity, or inks containing a coarse filler as an ink in the ink.
Is filled in the ink storage tube 10, and a grease-like follower 12 is provided at the rear end of the ink so as to follow the ink as the ink is consumed. Follower 1 if necessary
A resin-made follower rod 13 having a specific gravity substantially equal to that of the follower is immersed in 2. The ink storage tube 10 is an extruded tube made of polypropylene resin or a metal tube.

When ink having poor fluidity is used, the ball valve and the valve chamber need to be set with a sufficient clearance dimension so as not to impair the fluidity of the ink. In order to operate at a low speed, an appropriate size and an appropriately large mass are required. That is, the joint structure as in the embodiment has a large valve chamber, and a large ball valve cannot be loosely fitted. There is also a method in which a ball valve is inserted from the rear end of the joint and a bush provided with a ball receiving seat is separately fixed to the joint. However, there is a disadvantage that the number of members increases and the cost increases.

[0018]

The embodiment shown in FIG. 1 shows a state in which the tip 6 is directed upward. At this time, the ball valve 8 is located on the ball receiving seat 4b of the valve chamber 4a and seals the guide hole 4g, so that the writing is performed upward. Therefore, even if the ink on the back surface of the tip ball 7 of the chip runs out, the ink is caught by the head and does not flow backward.
Therefore, when the tip 6 is turned downward, the ink can immediately flow out, and writing is prevented from being rubbed. (By the way, in the structure without the ball valve, the ink acts in the backward flow direction in the upward writing, so that air is entrapped in the chip, and the ink does not immediately follow in the downward writing, and the chip 6 is turned downward.) In this case, the tip ball 7 comes into close contact with the inner surface of the ball holding portion 6a of the chip by the action of the spring 9, thereby preventing direct current of ink and drying of the tip portion.

When the ball valve 8 is inserted into the valve chamber, the ball valve 8 presses the rear tapered portion 4e from the rear end of the joint 2 at the rear end 4d, so that the rear end 4d slides. Since the front and rear tapered portions are easily bent and deformed while moving, the ball receiving seat 4b is easily damaged without being damaged.
The ball valve 8 is loosely fitted in a. In addition, since a large ball valve is provided and a large ink flow path to the chip side can be formed, ink with low fluidity can be used without any problem.

[0020]

The structure and operation of the ballpoint pen refill of the present invention are as described above, and a mechanism for preventing the backflow of ink can be easily formed at the time of molding the joint.
Further, by forming the valve chamber using the above-mentioned concave portion, the ball valve can easily fit loosely into the valve chamber without damaging the ball receiving seat. A joint that is not affected by the chip can be designed, and an inexpensive ballpoint pen refill can be provided in which a member can be incorporated from one side with respect to the conventional example.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an entire ball-point pen refill according to an embodiment of the present invention, showing a state in which a chip is directed upward.

FIG. 2 is a longitudinal sectional view showing the whole of a conventional ballpoint pen refill.

FIG. 3 is an enlarged longitudinal sectional view of a tip portion of a ballpoint pen on which a ballpoint pen refill is mounted.

FIG. 4 is an enlarged longitudinal sectional view of a rear part of a ballpoint pen having a ballpoint pen refill mounted thereon.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ball-point pen refill 2 Joint 3 Front shaft part 3a Tip hole 3b Rear end hole 3c Step 3d Ridge 4 Rear shaft part 4a Valve chamber 4b Ball receiving seat 4c Rib 4d Rear end 4e Tapered part 4f Crack part 4g Guide hole Reference Signs List 5 flange 6 tip 6a ball holding section 7 tip ball 8 ball valve 9 spring 9a straight section 9b winding section 10 ink storage tube 11 ink 12 follower 13 follower rod 14 ballpoint pen refill 15 joint 15a front shaft section 15b rear shaft section 15c valve Chamber 16 Tip 17 Tip ball 18 Spring 19 Ball valve 20 Shaft barrel 21 Base 22 Cap 23 Seal spigot 24 Tail plug

Claims (1)

[Claims] 1. A tip of a thin tubular ball-point pen is pressure-bonded to the tip of a resin joint, an ink storage tube is fixed to a rear end, and a spring for pressing the tip ball into an inner hole of the joint is built in and a ball is provided. In a ball-point pen refill equipped with a backflow prevention mechanism for ink in which a valve is loosely fitted, an all-round concave portion is formed on the outer periphery of the rear shaft portion of the joint that is pressed against the ink storage tube. A tapered portion is formed on the inner surface, and a rib at a required position is formed on the front inner surface with the front tapered portion as a ball receiving seat. A valve chamber is formed between the ball receiving seat and the rib, and a rear shaft of the joint is formed. The ball valve presses the rear tapered portion from the rear end of the portion to elastically deform the concave portion in the expanding direction so that the ball valve is loosely fitted in the valve chamber, and the ball valve receives the ball when the tip is upward. The guide hole is configured to be closed in a liquid-tight manner in close contact with the seat, and the ink storage tube is filled with a low-viscosity ink such as a water-based or low-viscosity oil-based ink having a so-called shear thinning property. And a ballpoint pen refill having a grease-like follower disposed at the rear end of the ink so as to follow the ink as the ink is consumed.