JP2002356087A - Writing utensil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that an ink channel 111 is blocked with an anti-backflow agent 106, that is, the rear end of an ink barrel passage 111 is blocked resulting in the stoppage of an ink droplet fall and a consequent inability to write. SOLUTION: This writing utensil has an ink storage part, for storing ink, which is constituted of a large diameter part and a small diameter part, with a flow channel formed in the inner face of a connecting part between both diameter parts. In addition, the anti-backflow body composed of a soft material and a hard material is interposed in the ink storage part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing implement having an ink containing section containing ink, and more particularly to a writing implement having an ink containing section having a large diameter portion and a small diameter portion.

[0002]

2. Description of the Related Art In general, a writing instrument having an ink storage section (in most cases, an ink cylinder referred to as a refill or a cartridge) containing oil-based ink is supplied with the oil-based ink from the rear end opening of the ink cylinder. At the end of the oil-based ink, a viscous liquid (so-called grease) which is larger than the surface tension of the oil-based ink, is immiscible with the oil-based ink, and does not dry or deteriorate is arranged as an ink backflow preventer so as not to flow back. I have. Further, recently, as in the case of the oil-based ink, a low-viscosity aqueous ink or a medium having an intermediate viscosity between the oil-based ink and the water-based ink, a writing tool containing a so-called gel-like ink or a writing tool containing a water-based ink. Also,
Grease is disposed at the end of the ink as an ink backflow inhibitor.

Further, a writing implement using a gel ink or an oil-based ink has a property that the ink easily evaporates, and furthermore, the ink consumption is high in order to increase the writing density, and as a result, the writing distance is short. Had become something. Therefore, in order to increase the writing distance, it is often practiced to increase the filling amount of the ink by increasing the internal volume of the refill. However, since the ink is sealed with the ink backflow preventive agent located at the end of the ink, if the inner volume of the refill is increased, that is, if the inner diameter of the refill is increased, the sealing ability of the backflow preventive agent is increased. When the writing implement falls down from the desk, for example, the ink moves in the direction of the rear end and writing becomes impossible, and if
In some cases, ink flowed out from the rear end of the refill. In order to solve this problem, when the inner diameter of the refill is increased, a method of immersing a columnar float made of a resin molded article or the like in a backflow inhibitor has come to be adopted. Thereby, even if the inner diameter of the refill is large and the filling amount of the ink is large, the gap between the inner surface of the refill and the outer surface of the float is narrow, and the backflow preventing agent enters the gap,
Since the ink is sealed by its viscous force (and wetness),
Even if an impact is applied to the writing implement, it is possible to prevent the ink from moving toward the rear end as much as possible.

In recent years, it has become essential to attach a grip formed of, for example, a thermoplastic elastomer to a grip portion of a writing instrument as shown in FIG.
The grip 101 is mounted on a reduced diameter portion 103 formed in front of the shaft 102. Here, the small-diameter portion 1 is provided on the inner surface of the reduced-diameter portion 103 so that the wall thickness becomes uniform.
04 is formed. By forming the shaft 102 with a uniform thickness over substantially the entire area, a dent (generally referred to as “shrinkage”) or the like generated on the surface of the shaft 102 is prevented. Note that the grip 101 may be attached without forming the reduced diameter portion 103, but the grip 101 protrudes with respect to the shaft 102, which significantly lowers design quality. The ink is a straight pipe 1 having a diameter slightly smaller than the inner diameter of the reduced diameter portion 103.
05, and the pipe 105 has a backflow preventing agent 10
6 and the float 107 are interposed. Of course, at the end of the ink. And, at the tip of the pipe 105,
The tip member 108 is press-fitted and fixed.
A ballpoint pen tip 109 having a ball rotatably at the tip is fixed to the tip of 8.

[0005]

In the above prior art, since the tip member 108 is press-fitted into the inner surface of the tip of the pipe 105, a step 110 corresponding to the thickness of the tip member 108 is generated. The thickness of the step 110 is formed by the difference between the outer diameter of the tip member 108 and the diameter of the ink passage 111. The step 110 serves as a forward regulating portion of the foot 107 which advances with the use of the ink. Here, a problem arises. Ink passage 111 with backflow preventive 106
It will block you. That is, since the rear end of the ink cylinder path 111 is closed, the ink does not drop and writing becomes impossible. Here, step 1
When the float 107 comes into contact with the anti-reflux agent 1
Although it is possible to fill the ink passage 111 with 06, the amount of the ink is reduced while the amount of the backflow preventing agent 106 is increased, which is not practical.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a flow passage formed in a step so that even if the float abuts on the step, the backflow preventing agent follows the decrease in ink. A writing instrument having an ink storage portion in which ink is stored, wherein the ink storage portion includes a large-diameter portion and a small-diameter portion, and a flow passage is formed on an inner surface of a connecting portion between the large-diameter portion and the small-diameter portion. In addition, the gist is that an ink backflow preventive made of a soft material and a hard material is interposed in the ink storage portion.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS.
Reference numeral 1 denotes a crown that is pressed into the cap 2. In this embodiment, the cap 1 and the cap 2 are illustrated as separate bodies, but they may be integrated. On the front inside of the crown 1, while preventing the tip discharge portion of the ballpoint pen tip 3 from drying,
A packing 4 made of a rubber-like elastic body for preventing ink from evaporating from the ballpoint pen tip 3 is fixed. Also,
An elastically deformable clip 5 for storage in a pocket or the like is attached to the cap 2, but the clip 5 may be formed integrally with the cap 2 by injection molding or the like. A repelling member 6 made of a small coil spring having a load of, for example, about 20 g is disposed in the ballpoint pen tip 3.
Urges the ball B disposed at the tip of the ballpoint pen tip 3. By this biasing, the tip of the ball-point pen 3 is brought into pressure contact with the inner edge of the tip, thereby constituting a valve mechanism. In short, at the time of writing, the ball B retreats due to the writing pressure, and the ink flows out of the tip discharge portion of the ballpoint pen tip 3, and except during writing, the ball B moves forward to prevent the ink from flowing out.

The shaft 7 is formed of a thermoplastic resin such as polypropylene, and has an ink container formed therein. Further, a tip member 8 for connecting and fixing the ballpoint pen tip 3 is press-fitted and fixed to the tip end opening of the shaft 7. The tip member 8 is formed with a fitting projection 8a that fits with the cap 2 when not in use. further,
A grip 9 made of a rubber-like elastic body is provided on the outer periphery in front of the shaft 7.
Is arranged. The portion of the shaft 7 on which the grip 9 is disposed has an outer diameter of the grip 9 substantially equal to a rear outer diameter of the shaft 7 on which the grip 9 is not disposed. A step is provided. That is,
The reduced diameter portion is formed. Due to the formation of the reduced diameter portion, a step is also formed on the inner surface of the shaft 7, and the small diameter portion 10 is formed. This is because the shaft 7 is formed of a thermoplastic resin such as polypropylene, and when the thickness is approximately uniform, the formability is improved and the productivity is improved. On the other hand, a tail plug 1
1 is press-fitted and fixed. In the present embodiment, press-fitting and fixing are exemplified, but fixing by screwing may be used. At the rear end of the tail plug 11, an air hole 12 is formed. The air holes 12 are outside air introduction holes for ink to exchange air. In this example, the air holes 12 are formed at one position at the rear end, but the number is appropriate.

Reference numeral 13 denotes an anti-reflux agent such as grease, which is injected into the end of the ink on the rear end side of the shaft 7 and is contained therein. The anti-reflux agent 13 is obtained by gelling a non-volatile organic solvent. Specific materials include those obtained by gelling a non-volatile organic liquid such as petrolatum, silicone grease, silicone oil, polybutene, α-olefin oligomer, ethylene-α-olefin oligomer, and the like. In addition, the anti-reflux agent 13 is
The movement of the ink toward the rear end (so-called outflow of the ink from the ink storage section) is prevented. Anti-reflux agent 1
In 3, a float 14 molded from a thermoplastic resin such as polypropylene is immersed. This float 14
Corresponds to the hard material backflow prevention body of the present invention. The float 14 is arranged in the ink storage unit (the shaft 7 in the present invention).
This is particularly effective when the inside diameter of the grease becomes large, and is arranged together with the grease to enhance the backflow prevention function. The float 14 is formed from a large diameter portion 14a and a small diameter portion 14b as shown. This is because the float 14 moves forward following the ink reduction and reaches near the connecting step 15 between the large diameter portion 7a and the small diameter portion 10 of the shaft 7. At this time, the small diameter portion 14b of the float 14 can enter the small diameter portion 10 of the shaft 7. The float 14 has a small diameter portion 14b.
The following effects can also be obtained by forming. That is, at the time of assembly, after filling the ink and the anti-reflux agent, insert the float, then go through a process such as centrifugation to deaerate the air, but if a small diameter portion is formed at the tip of the float, This makes it easier to directly enter and immerse in the backflow inhibitor. This effect is particularly remarkable when the backflow inhibitor has a high viscosity.

The backflow preventive 13 may be made of a transparent material, but may be made of a colored translucent or opaque material. Also, the float 14 may be formed of a transparent material, but by being colored, the presence or absence of the float 14 at the time of assembly can be easily determined.
For example, when assembling by machine, float 1
4 can be easily determined by a sensor.

The connecting step 15 of the shaft 7 is formed with a groove-shaped flow passage 16 through which the ink and the backflow preventive agent 13 can pass. This flow passage 16 is substantially formed by forming a rib 17. In this example, the four ribs 17 are formed radially at equal intervals, but the present invention is not limited to this. However, it is preferable to form them at equal intervals. This is to prevent inclination when the float 14 comes into contact. The flow passage 16 allows the float 14 immersed in the backflow preventive agent 13 to contact the connecting step 15 and stop moving forward any more. After passing through the flow passage 16, the anti-reflux agent follows the ink where the 13 decreases.

[0012]

According to the present invention, there is provided a writing instrument having an ink containing portion for containing ink, wherein the ink containing portion has a large diameter portion and a small diameter portion, and the large diameter portion and the small diameter portion are connected. A flow passage is formed in the inner surface of the portion, and an ink backflow preventive made of a soft material and a hard material is interposed in the ink storage portion, so that writing can be performed well even when the amount of ink becomes small. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a longitudinal sectional view of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap 2 Cap 3 Ballpoint pen tip 4 Packing 5 Clip 6 Repellent member 7 Shaft 8 Tip member 9 Grip 10 Small diameter portion 11 Tail plug 12 Air hole 13 Backflow preventive agent 14 Float 15 Connecting step 16 Flow channel 17 Rib

Claims (2)

[Claims] 1. A writing instrument having an ink storage portion in which ink is stored, wherein the ink storage portion includes a large-diameter portion and a small-diameter portion, and an inner surface of a connecting portion between the large-diameter portion and the small-diameter portion. A writing instrument, wherein a flow passage is formed, and an ink backflow preventive made of a soft material and a hard material is interposed in the ink storage portion. 2. The writing implement according to claim 1, wherein the backflow preventive body made of the hard member comprises a large diameter portion and a small diameter portion.