JPH056152Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a tail plug suitable for a writing instrument with a slide plug.

[Prior art and its problems]

In a writing instrument in which a bottomed ink cylinder is filled with ink and the ink is transferred to a pen body for writing, a pen core is usually interposed between the ink cylinder and the pen body. This pen core has the function of introducing air into the ink cylinder in an amount equal to the amount of ink consumed for writing, and the function of storing excessively ejected ink to prevent ink from dripping. Excessive ink is ejected because the writing instrument is left in a hot place, or when the temperature inside the ink cylinder rises due to the transfer of body heat from the scribe's hand, the air inside the ink cylinder expands. ,
This is because the pressure inside the ink cylinder increases and this pushes out the ink, but since there is a limit to the ink storage capacity of the pen core, if the discharge amount exceeds this limit, the ink will drip. Therefore, without using a pen core, a slide stopper that serves as a bottom is placed inside a bottomless ink cylinder, and the slide stopper moves forward as ink is consumed without replacing ink and air. Since there is no air in the ink cylinder, it is possible to prevent ink from dripping due to increased pressure, but it also reduces the number of parts and increases the capacity of the ink cylinder. It has the advantage of increasing the writable distance.

In such a writing instrument with a slide stopper, a tail stopper is fitted to the rear end of the ink barrel, which is a shaft cylinder, but in order for the slide stopper to move forward as ink is consumed,
A ventilation hole must be provided in the tail plug to supply air to the rear of the slide plug corresponding to the amount of advance of the slide plug. On the other hand, some of the ink leaks from the slide stopper and comes out to the rear of the slide stopper, but if the tail plug has great ventilation, the ink evaporates and the ink in the ink cylinder decreases in a relatively short period of time. . Furthermore,
If a small amount of ink comes out behind the slide stopper,
There is a problem where ink leaks to the outside through the ventilation hole in the tail plug. As described above, tail plugs are required to have the contradictory properties of breathability and airtightness or liquidtightness, but the reality is that no tail plug has been obtained that satisfies both of these properties at the same time.

In addition, not only writing instruments with a slide stopper, but also the refill built into the lock-type writing instruments of the Cat Press, ink consumption can be measured from the tail stopper, which houses a batting that absorbs ink inside and is fitted at the rear end. The situation is the same for those that allow equivalent air to enter.

[Purpose of invention]

Therefore, the present invention has a simple structure that satisfies breathability and airtightness or liquidtightness at the same time, reduces the amount of ink evaporation, and eliminates the risk of leakage to the outside.
The object of the present invention is to provide a tail plug for a writing instrument suitable for a writing instrument with a slide plug.

[Structure of the idea and its effects]

The writing instrument tail plug of this invention has a cylindrical main body with a
An upper annular projection and a lower annular projection are formed in close contact with the inner circumferential surface of the shaft cylinder, and a first ventilation hole and a second ventilation hole are bored between the upper annular projection and the lower annular projection with a distance of approximately 180 degrees from each other. The first ventilation hole and the second ventilation hole are separated by a partition inside the cylindrical body, and inside the cylindrical body below the partition,
The ink leak prevention member has a vent tube having a third ventilation hole in the axial direction protruding downward from the flange, and the flange is fitted and fixed to the inner wall of the cylindrical body, and an ink reservoir is formed around the vent tube. It is characterized by being formed.

That is, since the upper annular projection and the lower annular projection are in close contact with the inner peripheral surface of the shaft cylinder, a circumferential gap is created between the inner peripheral surface of the shaft cylinder between the two projections and the outer peripheral surface of the tail plug body, and the inside of the shaft cylinder is It communicates with the outside through the third ventilation hole, the second ventilation hole, the circumferential gap, and the first ventilation hole. Therefore, although it has sufficient air permeability, since the communication path is long, it is difficult for ink vapor to escape to the outside through this communication path, and evaporation of the ink is suppressed. Since the ink leak prevention member protruding downward from the vent tube is fitted and fixed, the area around the vent tube becomes an ink reservoir, and even if a large amount of ink flows toward the tail plug, the vent tube The third
It does not easily enter the ventilation holes, so ink does not leak outside.

〔Example〕

The present invention will be specifically described below based on embodiments shown in the drawings.

The ink cylinder 1 also serves as a barrel of a writing instrument, and a pen body 2 is attached to the tip. The pen body 2 is a marker made of plastic having open cells, but it may also be a ballpoint pen tip or the like. A tail plug 10, which will be described later, is fitted into the rear end opening of the ink cylinder 1. A slide plug 3 is slidably disposed inside the ink cylinder 1, and the water-based ink is placed in front of the slide plug 3. Filled. A valve stopper 4 is fixed in the vicinity of the pen body 2 inside the ink cylinder 1, and the ink chamber 1 is divided into a main ink chamber 5 and a sub-ink chamber 6. The valve plug 4 is a cylindrical body made of an elastic material such as silicone rubber, and has a flange-shaped valve portion 4a formed at its tip.
is in contact with the inner peripheral surface of the ink cylinder 1. Flange-shaped valve part 4
a is deformed by a slight pressure difference between the main ink chamber 5 and the sub-ink chamber 6, and
The water-based ink is allowed to flow into the ink.

The tail plug 10 is composed of two parts: a cylindrical main body 11 and an ink leak prevention member 21. Cylindrical body 11
Two annular protrusions, an upper annular protrusion 12 and a lower annular protrusion 13, are formed on the outer peripheral surface of the ink cylinder 1.
Airtightly adheres to the inner peripheral surface of the Therefore, a circumferential gap 14 is formed between the outer peripheral surface of the cylindrical body 11 and the inner peripheral surface of the ink cylinder 1. A first ventilation hole 15 and a second ventilation hole 16 are formed between the upper annular projection 12 and the lower annular projection 13, and are opposed to each other with a distance of approximately 180° from each other.
and the second ventilation hole 16 are separated by a partition wall 17 with different levels. When the partition wall 17 is planar, the first ventilation hole 15 and the second ventilation hole 16 are provided above and below the partition wall 17, respectively.

The ink leak prevention member 21 extends from the collar to the ventilation cylinder 2.
2 protrudes downward, and the inside of the ventilation cylinder 22 is a third ventilation hole 23. In other words, the ink leak prevention member 2
1 has a substantially T-shaped cross section. Then, the flange of the prevention member 21 is fitted onto the inner wall of the cylindrical main body 11 below the partition wall 17, and the ink leakage prevention member 21
is fixed to the cylindrical body 11. Therefore, inside the ink cylinder 1, the third ventilation hole 23 → the second ventilation hole 1
6→circling gap 14→first ventilation hole 15, which communicates with the outside through a long ventilation path. Further, a space is created around the ventilation cylinder 22, and this space is an ink reservoir portion 24.

When the water-based ink in the sub-ink chamber 6 is consumed by writing, the pressure in the sub-ink chamber 6 decreases and the brim-like valve portion 4a deforms. Therefore, the water-based ink in the main ink chamber 5 flows into the sub-ink chamber 6,
The sub-ink chamber 6 is always filled with water-based ink.
On the other hand, this lowers the pressure in the main ink chamber 5, and the slide plug 3 slides forward by the amount of water-based ink consumed. At this time, air enters the rear of the slide plug 3 through the aforementioned ventilation path of the tail plug 10. Although some of the water-based ink oozes out behind the slide stopper 3, the vapor of the ooze out ink is difficult to escape to the outside and hardly evaporates because the ventilation path of the tail stopper 10 is long. Therefore, even if left for a long period of time, the amount of ink loss is extremely small. Furthermore, even if a large amount of ink comes out behind the slide plug 3, it will not accumulate in the ink reservoir 24,
The possibility of entering the third ventilation hole 23 is extremely low, and there is almost no possibility of leakage to the outside.

In addition, although this example shows an example applied to a writing instrument with a slide stopper, it is possible to store the batting that absorbs ink inside and draw air equivalent to the amount of ink consumed from the tail plug fitted at the rear end. A similar effect can be obtained by applying it to the refil that is entering.

[Effect of idea]

As explained above, the tail plug of the present invention has a long ventilation path and an ink leak prevention member that forms an ink reservoir around the ventilation cylinder, so it has good ventilation and airtightness or liquidtightness. At the same time, it is possible to provide a tail plug for a writing instrument that satisfactorily has a small amount of ink evaporation and is free from the risk of leaking to the outside.

[Brief explanation of the drawing]

The drawing is a sectional view of an embodiment of the present invention. 1... Ink cylinder (shaft barrel), 2... Pen body, 3...
...Slide plug, 4...Valve plug, 5...Main ink chamber, 6...Sub-ink chamber, 10...Tail plug, 11...
Cylindrical body, 12... Upper annular projection, 13... Lower annular projection, 14... Circumferential gap, 15... First ventilation hole, 16... Second ventilation hole, 17... Partition wall, 21...
...Ink leak prevention member, 22... Ventilation cylinder, 23...
...Third ventilation hole, 24...Ink reservoir section.

Claims (1)

[Scope of utility model registration request] An upper annular protrusion and a lower annular protrusion are formed on the outer periphery of the cylindrical body, and the upper annular protrusion and the lower annular protrusion are in close contact with the inner circumferential surface of the shaft cylinder, and a first vent hole and a second vent hole are formed mutually between the upper annular protrusion and the lower annular protrusion. The first ventilation hole and the second ventilation hole are separated by a partition wall inside the cylindrical body, and a flange is provided inside the cylindrical body below the partition wall. An ink leak prevention member having a vent tube having a third ventilation hole extending in the axial direction protrudes downward from the ink leak prevention member is fixed by fitting the collar portion to the inner wall of the cylindrical body, and an ink reservoir is formed around the vent tube. A tail plug for a writing instrument.