JP3924933B2 - Writing instrument - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a writing instrument in which a pen tip is slidably disposed while protruding from the tip opening of a shaft tube, and an ink passage hole of a valve mechanism is opened by rearward movement of the pen tip rear end.
[0002]
[Prior art]
Conventionally, various writing instruments having an ink tank for containing ink in a free state are known, but when ink is consumed and the amount of ink in the ink tank decreases, the pressure in the ink tank decreases and ink is supplied to the pen tip. Therefore, air is taken into the ink tank at the same time as ink consumption, and the ink tank is kept at a constant pressure (atmospheric pressure). Among such writing instruments, there is known a writing instrument in which ink is supplied to the pen tip by opening an ink through hole of the valve mechanism by an operation between the ink tank and the pen tip via a valve mechanism. When the ink passage hole is opened, the ink flows out, and at the same time, air is taken into the ink tank through the ink passage hole and the inside of the ink tank is maintained at a constant pressure (atmospheric pressure).
[0003]
[Problems to be solved by the invention]
In a conventional writing instrument in which the ink / air replacement in the ink tank is performed as the ink is consumed and air is actively present in the ink tank, the air present in the ink tank becomes a problem. That is, when the writing instrument itself is placed in a high temperature environment, the air in the ink tank expands and increases the pressure in the ink tank. If the ink passage hole is opened in this state, the compressed air is suddenly released to push out the ink and supply more ink than necessary to the pen tip. Therefore, there has been a problem that the phenomenon of ink blowing out and dropping off occurs. Such phenomena such as ink blowout and drop-off occur especially when the volume of air (bubbles) in the ink tank exceeds 20% of the volume of the ink tank. In order to prevent the volume of air from becoming 20% or more of the ink tank volume, it is more preferable to keep the volume within several% of the ink tank volume.
[0004]
In addition, in writing instruments that allow air to exist in the ink tank, the ink is controlled by gravity, and when the ink amount is small to some extent, when the pen tip is turned sideways, the ink passage of the valve mechanism Ink did not reach the ink, and no matter how much the ink through hole was opened, no new ink was supplied to the pen tip, and there was a problem that the handwriting was faded or writing was impossible.
[0005]
That is, the present invention relates to a writing mechanism in which a pen tip is slidably disposed while protruding from the tip opening of a shaft tube, and the ink passage hole of the valve mechanism is opened by rearward movement of the pen tip rear end. thereby forming an open mouth at the rear end portion of the ink tank to be connected to, to place the highly viscous fluid which moves to follow the surface to advance with a decrease in the amount of ink by writing, ink communication of at least the valve mechanism The gist of the writing instrument is characterized in that when the hole is opened, the pen tip side opening edge of the ink passage hole is in airtight contact with the pen tip or the cylindrical ink absorber that wraps the pen tip .
[0006]
【Example】
Hereinafter, an example will be described with reference to the drawings.
The rear part of the shaft cylinder 1 made of polypropylene resin is used as an ink tank 2 as it is, and a pen tip 3 made of an acrylic fiber converging body is arranged on the front part of the shaft cylinder 1 so as to be movable back and forth. This is an example of a nib-knock type writing instrument using a so-called valve mechanism in which a valve mechanism including a valve seat 4 and a valve body 5 is interposed therebetween. A tail plug 6 is fitted to the rear end of the shaft tube 1 so that air can freely enter the shaft tube 1 through a vent hole 6a. The valve body 5 is pressed against the valve seat by a coil spring 7 in a normal case, and the supply of the ink 8 in the ink tank 2 to the pen tip 3 is blocked. When a pressing force such as writing pressure is applied to the pen tip 3, the pen tip 3 moves backward, and the valve body 5 connected to the pen tip 3 also moves backward while receiving the elastic force of the coil spring 7. At this time, a gap between the valve seat 4 and the valve element 5 is formed as an annular ink passage hole in the center hole of the valve seat 4, and ink in the ink tank flows out and is supplied to the pen tip 3.
[0007]
A high-viscosity fluid 9 made of polybutene, α-olefin, or the like is disposed in layers at the interface position of the ink 8 accommodated in the ink tank 2. That is, the ink in the ink tank 2 is in a state where the pen tip side is closed by the valve mechanism and the rear end side is closed by the high viscosity fluid 9. The high-viscosity fluid 9 has a viscosity of about 50,000 to 200,000 mPa · s, and a part of the high-viscosity fluid 9 is attached to the inner wall of the shaft tube 1 and remains as the ink interface moves to the pen tip side as the ink amount decreases. As a whole, the ink interface moves to the pen tip side while closing the ink interface. When the viscosity of the high-viscosity fluid is low and the diameter of the ink tank 2 is large, the layer of the high-viscosity fluid 9 may be broken. The stopper 10 is positioned in the layer of the high-viscosity fluid 9 so that the high-viscosity fluid 9 is formed substantially as a narrow space between the floating stopper 10 and the shaft tube 1. As the occupied volume of the ink 8 and the high-viscosity fluid 9 stored in the shaft cylinder 1 decreases, outside air is supplied from the vent hole 6a of the tail plug 6 so that the pressure in the shaft cylinder 1 is constant (atmospheric pressure). Maintained. In addition, when the ink passage hole of the valve mechanism is opened, the rear end of the pen tip is located in the center hole of the valve seat 4 so that the ink is smoothly supplied to the pen tip 3 and the air enters the ink tank. Suppresses as much as possible. Accordingly, a state where air does not actively exist can be formed in the ink tank 2 partitioned by the shaft cylinder 1, the valve mechanism, and the high-viscosity fluid 9, and excessive supply of ink to the nib 3 due to the expansion of air is prevented. The ink is suppressed as much as possible, and it is difficult for ink to blow out and drop off. In addition, a state where ink is always in contact with the ink passage hole of the valve mechanism is formed. Even when the pen tip is turned sideways (perpendicular to the direction of gravity), if the valve mechanism is opened, the ink is transferred to the pen tip 3. It can be supplied, and it is difficult for blurring of handwriting and inability to write.
[0008]
Even in the above example, there is a possibility that some air may enter the ink tank 2 when the valve mechanism is opened. However, the following example tries to suppress the intrusion of air from the ink passage hole of the valve mechanism as much as possible. To do.
[0009]
The example shown in FIGS. 2 to 4 is a front shaft in which a polypropylene resin pipe body 11 forming an ink tank 2 is covered with an exterior body 12, and a front end of the exterior body 1 is disposed with a pen tip 3 inside. 13 is connected. The pipe body 11 has its front end pressed against the valve mechanism while its rear end is opened in the exterior body 12. In the pipe body 11, the ink 8 and the high-viscosity fluid 9 are accommodated. A vent hole 14 is formed in the side wall of the exterior body 12, and the space between the pipe body 11 and the exterior body 12 communicates with the outside air, and this space is always kept at the same temperature and pressure as the outside air.
[0010]
The difference of the example of FIG. 2 is that an ink absorber 15, which is a cylindrical fiber converging body that wraps the pen tip 3, is disposed in the front shaft 13. The rear end of the ink absorber 15 is in contact with the opening edge of the ink passage formed on the side of the valve seat 4 so as not to form a space where air exists in the vicinity of the opening of the ink passage. is there. As a result, the possibility of air entering the ink tank 2 can be further reduced. More preferably, when assembling a writing instrument, by using a pen tip and an ink absorber impregnated with ink in advance, air does not easily enter the ink tank even when the ink passage hole is opened for the first time. can do.
[0011]
FIG. 3 shows another example.
The opening edge of the ink passage hole is covered with the pen tip 3 to suppress the intrusion of air from the ink passage hole into the ink tank 2. That is, the concave portion 3a is formed at the rear portion of the pen tip 3, and the tip portion of the valve body 5 is accommodated in this portion. The outer portion of the recess 3a is always in contact with the opening edge of the ink passage on the valve seat 4 side, and when the pen tip 3 moves rearward, the compression portion 3b is elastically deformed by the pressure. The space where air exists is not provided as much as possible near the opening edge of the ink passage hole, and the compression part 3b temporarily discharges the ink existing in the part to the peripheral part by compression to form an ink film. Suppress intrusion.
[0012]
In the example shown in FIG. 4, the rear end of the pen tip 3 is made larger than the diameter of the ink passage hole and is brought into contact with the opening edge on the valve seat 4 side of the ink passage as in the example of FIG. 3. However, it is assumed that the nib 3 is composed of a relatively hard central portion 3c for applying a pressing force to the valve body 5 and a relatively soft coating layer 3e that can be elastically deformed. This is in contact with the opening edge on the 4th side. Such a nib can also be obtained by forming the center portion as a fiber bundle so that the fibers are in a denser state.
[0013]
【The invention's effect】
From the above, the writing instrument of the present invention can supply ink to the pen tip even when the pen tip is turned sideways, and suppresses blurring and inability to write as much as possible, and when the writing instrument is placed in a high temperature environment. The ink can be prevented from blowing out and dropping off as much as possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example.
FIG. 2 is a cross-sectional view showing another example.
FIG. 3 is a cross-sectional view showing still another example.
FIG. 4 is a cross-sectional view showing still another example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Ink tank 3 Nib 3a Recess 3b Compression part 3c Center part 3e Covering layer 4 Valve seat 5 Valve body 6 Tail plug 6a Vent hole 7 Coil spring 8 Ink 9 High viscosity fluid 10 Floating plug 11 Pipe body 12 Exterior body 13 Front shaft 14 Ventilation hole 15 Ink absorber

Claims (6)

An ink tank connected to the valve mechanism in a writing instrument in which the pen tip is slidably arranged protruding from the tip opening of the shaft cylinder and the ink passage hole of the valve mechanism is opened by the rearward movement of the pen tip rear end. A high-viscosity fluid that moves following the interface that moves forward as the ink amount decreases by writing is arranged at the rear end of the valve mechanism, and at least when the ink passage hole of the valve mechanism is open A writing instrument characterized in that the pen tip side opening edge of the through hole is in airtight contact with the pen tip or a cylindrical ink absorber that wraps the pen tip. The valve mechanism is composed of a valve seat having a center hole and a valve body that abuts on the valve seat and closes the center hole, and the valve body is moved forward and backward in the center hole while being urged forward by an elastic member. It is arranged to form an annular ink passage hole, and the pen tip is brought into contact with the valve body to contact the valve body side opening edge of the ink passage hole. The writing instrument according to claim 1, wherein a cylindrical ink absorber that wraps the pen tip is brought into contact. When the ink passage hole of the valve mechanism is opened, the pen tip has a rear end located behind the pen tip side opening edge of the ink passage hole and contacts the pen tip side opening edge of the ink passage hole. The writing instrument according to claim 1, wherein the writing instrument is provided. When the rear end portion of the nib has a diameter larger than the central hole of the valve seat, and the pen point is moved backward to move the valve body to open the ink passage hole, the central hole of the valve seat of the nib The writing instrument according to claim 1 or 3, wherein a larger diameter portion is a compression portion that is elastically deformed while being in contact with the valve seat. 5. The writing instrument according to claim 4, wherein the pen tip is composed of a relatively hard portion at a central portion and a relatively soft portion surrounding the pen tip. The ink tank is a straight pipe, the shaft cylinder is an exterior member that covers the rear end of the ink tank, and the space formed between the ink tank and the cylinder is communicated with the outside air. The writing instrument according to any one of claims 1 to 5, wherein a ventilation hole is formed.

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