JPH09272291A - Direct liquid type writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a fear of leaking ink from an air vent of a tail cap fitted on the tail end of a shaft cylinder to the outside even in the case of losing the sealing effect of a backflow preventing agent when a writing instrument is placed facing upward. SOLUTION: In a direct liquid type writing instrument in which ink is directly filled in a shaft cylinder 1 with a pen body tip 2 disposed at the front end and a tail cap 5 fitted on the tail end and the tail end side of the ink is sealed by a paste-like backflow preventing body 6, a check valve constituted of a valve 9 as a ball and a seat component 8 is disposed on the tail cap 5, and an ink reservoir section 53 is formed on the tail end side of the check valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct liquid writing instrument in which ink is directly filled into a barrel having a pen tip at the tip thereof.

[0002]

2. Description of the Related Art For example, a ball-point pen using water-based ink has been put into practical use of a filling type in which ultrafine fibers are aligned to form a rod-shaped filling to absorb the ink, and the filling is housed in a shaft cylinder. However, this batting-type writing instrument has a problem in that the amount of ink absorbed is limited and the writable distance is short, and the end point at which writing becomes impossible due to exhaustion of the ink is difficult to understand.

[0003] On the other hand, a direct liquid type writing instrument in which ink is directly filled in a barrel and does not use a batting has advantages that the end point is clear and the writing distance is long because the ink can be directly visually observed. When the air in the barrel becomes hot and expands, such a direct liquid type writing instrument discharges ink excessively and drops.Therefore, the excessively discharged ink is temporarily stored to prevent the dropping of the ink, and the ink is discharged. In many cases, a pen core having a gas-liquid exchange function for introducing air into the shaft cylinder with the consumption of is disposed, but the pen core has a complicated structure and a problem of increasing the number of parts.

For this reason, the tail end side of the shaft cylinder whose tail end communicates with the outside air is sealed with a paste-like backflow preventing body, and a water-based ink called gel ink is filled in front of the backflow preventing body. A raw ink writing instrument in which the space between the pen tip and the backflow preventer is filled only with ink has been put into practical use. The gel ink statically has a relatively high viscosity, but the viscosity of the gel ink decreases due to the rotation of the ball during writing, and the ink flows out.
Therefore, the backflow preventer advances as the ink is consumed, and the backflow preventer prevents the backflow of ink.
Since only the ink exists and the air does not exist in front of the backflow preventer, the ink is not pushed out by the air that has become hot and expanded.

By the way, when such a direct liquid type writing instrument is placed in an upward posture, the ink head is caught by the backflow preventive agent,
The anti-reflux agent flows backward and descends toward the tail end opening side. For this reason, a check valve or the like is arranged on the pen tip so that the check valve closes and the ink head does not come into contact with the backflow preventive agent when the writing instrument is in the upward posture.

[0006]

However, since the check valve seal of the pen body tip is not always perfect, air is introduced from the pen body tip into the barrel.
The ink head may come into contact with the anti-reflux agent. Therefore, the backflow preventing agent drops to the tail end opening side of the barrel, but at this time, the backflow preventing agent adheres to the wall surface of the barrel during the descending process, the sealing effect is lost, and the ink is removed from the air in the tail plug. There is a risk of leaking to the outside through the hole, and if it leaks when it is worn in a pocket, it will contaminate your clothes.

For this reason, a check valve having a ball as a ball is provided in the air hole of the tail plug, and the check valve opens at the time of writing, so that air is introduced from the air hole into the barrel as ink is consumed. Although it enters, this check valve closes when it is in the upward posture,
Even if the sealing effect of the backflow preventive agent is lost, it has been proposed that the check valve prevent the ink from leaking out.

However, the check valve provided on the tail plug does not come into contact with the ink under normal conditions, and therefore the contact portion between the valve body of the ball and the valve seat is not sealed by the capillary action of the ink, so that the sealing effect is not achieved. Not perfect. Therefore, when the backflow preventive agent loses its sealing effect and ink reaches the check valve for the first time, the first ink leaks a little even though the valve element of the ball is in contact with the valve seat. Then, this ink may leak from the air hole of the tail plug and stain the clothes.

Therefore, according to the present invention, even if the backflow preventive agent loses its sealing effect when the writing instrument is in the upward posture, the ink leaks to the outside from the air hole of the tail plug fitted to the tail end of the barrel. It is an object to provide a direct liquid writing instrument that is not likely to come out.

[0010]

In order to achieve the above object, the present invention directly fills ink into a barrel having a pen tip disposed at the tip and a tail plug fitted at the tail. In addition, in a direct liquid type writing instrument in which the tail end side of the ink is sealed by a paste-like backflow prevention body, a check valve with a ball as the valve body is arranged on the tail plug, and the ink is attached to the tail end side of the check valve. Form a reservoir.

That is, since the check valve having a ball as the valve body is arranged on the tail plug and the ink reservoir is formed on the tail end side of the check valve, when the pen tip is in the upward posture, Even if the sealing effect of the backflow preventive agent is lost and ink slightly leaks from the check valve, the leaked ink is retained in the ink reservoir of the tail plug. Therefore, it is possible to prevent the ink from leaking from the air hole of the tail plug.

[0012]

Embodiments of the present invention will be specifically described below with reference to the drawings. In FIG. 1, the shaft cylinder 1
Is an injection-molded transparent synthetic resin with an inner diameter of 7.0 mmφ
The inner diameter is larger than that of the shaft cylinder of the conventional direct liquid writing instrument, and therefore a large amount of ink can be filled. The pen body tip 2 of the ballpoint pen is attached to the front opening 11 at the tip of the barrel 1.

The pen body tip 2 is formed of stainless steel in a bullet shape, and a ball house made of cemented carbide is partially exposed from the tip of the pen body tip 2 in a ball house at the tip of the pen body tip 2. It is held in a freely rotatable state when it is taken out. A small spring 4 having a spring force of, for example, 40 g is arranged in the pen body tip 2.
Repulsively ejects the ball 3 against the inward tip end edge of the pen body tip 2, and the ball 3 and the tip edge constitute a valve mechanism. That is, when writing, the ball retreats due to writing pressure and ink flows out, and when not in use, the pen tip 2 is sealed and plays the role of a check valve.

Inside the tail end side of the shaft cylinder 1, a light columnar body 7 having a bottomed cylinder shape is arranged. The columnar body 7 has an outer diameter of 6 mmφ and a length of 15 mm, for example. Around the columnar body 7, a paste-like backflow preventer 6 made of, for example, a polybutene compound is applied.
The gap between the inner peripheral surface and the columnar body 7 is filled. That is, the tail end side of the shaft cylinder 1 is sealed by the columnar body 7 to which the paste-like backflow preventive body 6 is applied.

The shaft cylinder 1 in front of the columnar body 7 is filled with gel ink (not shown) having a viscosity of, for example, 30 to 40 cps, and no air exists in the shaft cylinder 1 in front of the columnar body 7. . When the ink is consumed by writing, the columnar body 7 coated with the paste-like backflow preventive body 6 moves forward accordingly, but since the inner diameter of the barrel 1 is large and the internal volume is large, a large amount of ink is consumed. The ink I can be filled in the barrel 1, which has the advantage of a long writing distance.

A tail plug 5 is fitted into the tail end opening of the barrel 1. The tail plug 5 has a bottomed tubular shape and a tubular portion 5 on the bottom surface thereof.
1 are continuously connected to each other, and the inside of the tubular portion 51 is an air hole 52. The outer peripheral surface of the tubular portion 51 and the inner peripheral surface of the bottom portion of the tail plug 5 constitute a bag-shaped portion, and this bag-shaped portion is the ink reservoir 53. A valve seat 81 and a valve seat member 8 having a plurality of semicircular protrusions 82 are fitted in the tip opening of the tail plug 5, and a valve body 9 made of a ball is arranged in the valve seat member 8 back and forth. The valve seat member 8 and the valve body 9 are movably arranged.
Constitutes a check valve. Therefore, when writing, the valve 9
Is held by the semicircular projection 82, air passes around the valve body 9, and when it is in an upward posture, the valve body 9 is seated on the valve seat 81.

However, when the writing instrument is placed in an upward posture such as when it is worn in a pocket, the tip opening of the pen tip 2 is sealed by the ball 3 repelled by the spring 4, so that the ink The head does not come into contact with the columnar body 7 and the backflow preventing agent 6, and these do not descend.
However, should this seal be incomplete, the head of the ink will come into contact with the columnar body 7 and the backflow preventive agent 6, and these will flow back and fall, and in the process, they will adhere to the wall surface of the barrel 1 and seal. The effect may be lost.

When the sealing effect of the backflow preventive agent 6 is lost, the ink reaches the valve body 9 seated on the valve seat 81.
At this point, the seating portion is not sealed with ink, so the ink leaks a little. The ink leaking from the check valve drops along the inner surface of the tail plug 5, but since the ink pool 53 is formed at the bottom of the tail plug 5, the ink collects in the ink pool 53 and air. It is possible to prevent leakage from the hole 52 to the outside. Therefore, the clothes are not soiled.

[0019]

As described above, in the direct liquid type writing instrument of the present invention, the check valve having a ball as the check valve is attached to the tail plug fitted to the tail end of the barrel directly filled with ink. In addition to arranging it, an ink reservoir is formed on the tail end side of the check valve, so even if the backflow preventative agent descends and the sealing effect is lost in the upward posture, the check valve will be slightly The leaked ink can be used as a direct liquid type writing instrument in which the ink does not leak to the outside through the air holes of the tail plugs.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 11 Tip part 2 Pen body tip 3 Ball 4 Spring 5 Tail plug body 51 Tubular body 52 Air hole 53 Ink reservoir part 6 Backflow prevention body 7 Columnar body 8 Valve seat member 81 Valve seat 82 Semicircle projection 9 Valve body

Claims (1)

[Claims] 1. A pen tip is arranged at the tip, ink is directly filled in a barrel having a tail plug fitted at the tail end, and the tail end side of the ink is sealed by a paste-like backflow preventer. In the direct liquid writing instrument, a check valve having a valve body as a ball is arranged in the tail plug, and an ink reservoir is formed at the tail end side of the check valve. Writing instrument.