JPH0218997B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an ink tank in a writing instrument, a so-called marking pen, which stores water-based ink inside and allows the ink to flow and be supplied to the pen tip by capillary action.

Conventionally, ink tanks for water-based marking pens of this type have a fiber aggregate in the form of a rod, with both ends open and the outer circumferential surface coated with synthetic resin or cellulose film, in which water-based ink is stored. However, synthetic fibers are usually hydrophobic;
Since it is difficult to absorb ink, it was necessary to make the surface of the constituent fibers hydrophilic.

There are two methods used to make synthetic fibers hydrophilic: a chemical modification method that forms hydrophilic groups on the fiber surface, and a surfactant treatment method. Currently, fiber bundles are made hydrophilic by treatment with an activator.

However, surfactant-treated tow or sliver is used as an ink absorbing body for an ink tank as a bundle-like aggregate, so there is no bond between fibers and the fibers tend to move and fall off, making it unstable. When the pen is housed in the pen barrel and used, the flow of ink to the nib core often becomes excessive, and due to the impact of dropping the pen body, the ink in the ink tank flows and flows out, resulting in so-called ink spillage. This method has many drawbacks, such as dripping accidents and a large amount of ink remaining when recording fails.

The present invention is intended to solve the various drawbacks of an ink tank for a water-based marking pen that uses a hydrophilized fiber aggregate as a water-based ink storage body as described above.

In other words, it has been thought that the surface of the fiber aggregate in conventional ink tanks needs to be made hydrophilic in order to absorb and flow the water-based ink by capillary action, and various methods have been used for this purpose. ,
The present invention is based on an idea completely opposite to the conventional one, and uses a bundle-like aggregate of hydrophobic synthetic fibers that have not been made hydrophilic as is as an ink storage body, and coats the outer periphery of the ink storage body with a water-impermeable synthetic resin. A fixed amount of water-based ink is forcibly filled into the ink storage body in the ink tank body, and at this time, fiber bundles that are not impregnated with water-based ink are placed at both ends of the ink tank. It was established.

The ink tank of the present invention has the above-described structure, and the water-based ink is fully impregnated into the ink storage body in the central part of the tank excluding both ends, and the water-based ink is retained by the capillary action between the bundled fibers. Under the balance of the interfacial tension between the surface of the hydrophobic synthetic fiber and the water-based ink and gas phase in the non-ink-impregnated area, the water-based ink fully impregnated in the central area effectively flows to the open surfaces at both ends of the ink tank. It also absorbs fluctuations in ink volume due to temperature and atmospheric pressure, etc., and does not cause ink to adhere to the end surface or outer peripheral surface of the ink tank, making it extremely easy to handle. When the ink fluid wick connected to the pen tip is inserted through the non-ink-impregnated part of the ink tank so as to reach the ink-filled part, a replenishing flow of ink is generated toward the ink fluid wick, and the ink tank More than 80% of the ink stored in the tank effectively flows to the pen tip, and the effective recording distance is increased by more than 20% compared to the case of an ink tank using a conventional hydrophilic fiber absorber, which is a favorable result. That's what you get.

Most of the commercially available synthetic fibers for industrial materials for clothing can be used as the hydrophobic synthetic fibers used in the present invention, but olefin-based fibers such as polypropylene and polyethylene, which have particularly excellent hydrophobicity, and polyester-based fibers can be used. Preferably, these are long fiber tows or short fiber slivers that are bundled together and the outer peripheral surface of the bundle is coated with a synthetic resin.
It is cut into a predetermined length, usually about 6 to 10 cm, to form the ink tank body.

The tow and sliver mentioned above may contain 30% or less of other synthetic fibers mixed with the preferred synthetic fibers.

In addition, to prevent some of the constituent fibers from moving or falling off, these tows and slivers are welded and fixed at the points of contact between the fibers using solvent vapor treatment, or the tows and slivers are subjected to a light needle punching process. It is desirable to entangle the fibers to provide shape-retaining stability as a fiber bundle, thereby preventing the performance of the ink tank from deteriorating during use of the marking pen.

The volume ratio of the hydrophobic synthetic fiber that serves as the ink storage body in the ink tank is 15 to 20%, that is, the porosity is 80 to 20%.
85% is preferable, and if the length of the non-ink-impregnated portion provided at both ends of the ink tank is approximately 5 mm or more within the above fiber volume ratio range, the internally stored ink will flow out under normal handling conditions. Marking pens using this ink tank are tested in the normal ink drop test, i.e., at a height of 1 m.
Even when a drop test was conducted with the pen shaft vertical, no excessive leakage or dripping of the occluded ink occurred.

To fill the ink tank body with water-based ink, use a plunger pump type metered injector to insert the injection needle into the ink storage body at least 20 mm and inject water-based ink at a moderate injection speed. Leaving a non-ink-impregnated area, the ink can be press-fitted into the center and completely impregnated.

The above ink injection speed is the volume of the ink tank,
This can be determined experimentally depending on the thickness, length, fiber density, and the orientation of the ink tank during injection, i.e., upright, horizontal, or slanted installation, and although it cannot be absolutely specified, it is usually When the injection needle is inserted approximately 25 mm through the fiber volume, the fiber volume is 18% and the inner diameter is 6.
If approximately 1.4 cc of water-based ink is injected in 1 to 2 seconds into an ink tank with an ink storage body of 80 mm in length and 80 mm in length, the ink will be absorbed by leaving a non-ink-impregnated area of approximately 5 mm length at both ends. Filling and impregnation was possible, but if the injection time was 1 second or less, some of the ink would flow out to either end, and the desired product could not be obtained. If this is done, not only will there be a difference in the range of the non-ink impregnated area at both ends, but some ink will flow to the ends, making the ink outflow effect uneven at both ends of the ink tank, resulting in almost the same excess as before. This not only increases the possibility of problems such as spillage and dripping, but also reduces production efficiency.

EMBODIMENT OF THE INVENTION Hereinafter, embodiments of the ink tank for a marking pen of the present invention will be described with reference to the drawings, together with a method for manufacturing the same.

Fig. 1 is a longitudinal cross-sectional side view of the ink tank of the present invention, and 1 is a 70% short fiber of 3 denier 100 mm cut polypropylene, 6 denier polypropylene.
It is a rod-shaped fiber aggregate made by thoroughly mixing and combing 30% short fibers of 100 mm cut, passing it continuously through trichlorethylene vapor, converging it into a rod shape, and welding the constituent fibers to each other. , 2 is a synthetic resin film such as polypropylene that coats the outer circumferential surface of the rod-shaped fiber aggregate 1, and 3 is filled with ink so as to leave ink-unimpregnated areas 4 and 5 at both ends of the rod-shaped fiber aggregate 1. This is a part impregnated with water-based ink.

FIG. 2 shows that the polypropylene fiber slivers described above are bundled after being treated with trichlorethylene vapor,
FIG. 3 is a partially enlarged side view of the rod-shaped fiber aggregate 1 in which welded portions 6 are formed at contact points of constituent fibers;
The figure is a partially enlarged sectional view of a rod-shaped fiber aggregate 1 in which entangled portions 7 of constituent fibers are formed by needle punching similar slivers from above and below at appropriate intervals. 15
It is said to be a shape-retaining rod-like body that has a fiber volume of ~20% and is suitable for saturation impregnation with water-based ink. The above structure can also be obtained using substantially the same method in the case of long fiber tow, and it is particularly preferable that the tow be crimped.

Fig. 4 shows a state in which water-based ink is injected into the ink tank body whose outer peripheral surface of the aforementioned rod-shaped fiber aggregate 1 is coated with synthetic resin. A certain amount of water-based ink is press-fitted at an appropriate injection speed using the injection needle 9 provided at the tip of the ink tank 8, leaving ink-unimpregnated areas 4 and 5 at both ends of the rod-shaped fiber aggregate inside the ink tank main body. Filled.

FIG. 5 shows that the ink tank of the present invention shown in FIG. 1 is loaded into a marking pen shaft 10, and a rod-shaped pen core shaft 11 made of a slightly hydrophilic synthetic resin, such as polyacetal, is provided with a liquid passage hole in the axial direction. The pen nib 12 protrudes to the outside and is held and fixed so that the rear end is inserted into the ink impregnated part 3 through the non-ink impregnated part 4 of the rod-shaped fiber aggregate 1, and a fitting lid 15 is provided at the rear end of the pen shaft 10. It is fitted to the rear end of the ink tank and becomes a marking pen. Of course, an appropriate cap is removably fitted on the side of the pen tip 12, and there is also a ventilation hole 1 on the tip side of the pen shaft 10.
6 and the space inside the rear fitting lid 15, for example, a ventilation groove is provided on the synthetic resin coating surface of the ink tank or the inner surface of the pen barrel 10 to prevent abnormal flow of ink due to changes in air pressure and temperature. is also exactly the same as before.

Since the ink tank of the present invention has the above configuration, as described above, there is no ink adhering to the outer surface of the tank, water-based ink is stably stored, and handling is easy. Drop-off is prevented, and the usage rate of the filled ink for writing is improved, that is, the amount of remaining ink at the point when writing is no longer possible is reduced to less than half that of conventional products using hydrophilic fiber aggregates. This avoids the problem of smearing of writing when treated with an active agent to make it hydrophilic, and not only is there no need for a surfactant at all during its production, but the ink filling process is also accurate and quick. This invention has a great effect of improving the performance and economic efficiency of marking pens using this ink tank, in addition to being able to manufacture an excellent water-based ink tank in an extremely efficient manner.

In addition, although the above-mentioned embodiment showed the case of a pen with a rod-shaped pen core, it goes without saying that it can also be effectively used as an ink tank in the case of a water-based marking pen having a brush-like nib or a ballpoint nib using a relay nib.

[Brief explanation of drawings]

The drawings show embodiments of the present invention.
The figure is a longitudinal side view of the ink tank, Figures 2 and 3 are partially enlarged side views of the rod-shaped fiber aggregate, and Figure 4 is a cross-section of the main part showing the state in which ink is press-filled into the ink tank body. Side view, FIG. 5 is a longitudinal sectional side view of the water-based marking pen with an ink tank inserted. 1... Rod-shaped fiber aggregate, 2... Synthetic resin film, 3...
Water-based ink impregnated part, 4, 5... Ink non-impregnated part, 6
...Welded part, 7... Entwined part, 8... Syringe, 9... Injection needle, 10... Marking pen shaft.

Claims (1)

[Scope of Claims] 1. An ink tank for a marking pen in which a bundle-like aggregate of hydrophobic synthetic fibers is used as an ink storage body and a synthetic resin film is formed on the outer periphery of the ink storage body, and an ink non-impregnated portion is provided at both ends of the ink storage body. An ink tank for a water-based marking pen, characterized in that a water-based ink is injected and occluded into the intermediate portion of the ink tank to form a water-based ink. 2. Claim 1, wherein the bundle-like aggregate of hydrophobic synthetic fibers is a rod-shaped body in which tows or slivers of polyolefin-based or polyester-based synthetic fibers are bundled and welded and bonded at mutual contact portions of the constituent fibers. Ink tank for water-based marking pens. 3 Claims in which the bundle-like aggregate of hydrophobic synthetic fibers is formed into a rod shape by intertwining the constituent fibers with each other by needle punching a tow or sliver of polyolefin-based or polyester-based synthetic fibers. An ink tank for a water-based marking pen according to item 1. 4. Insert the injection needle of a water-based ink injector into one end face of the bundle-like aggregate of hydrophobic synthetic fibers having a synthetic resin film on the outer peripheral surface, and insert the needle of the water-based ink injector into both ends of the bundle-like aggregate of hydrophobic synthetic fibers having a synthetic resin coating on the outer peripheral surface. A method for manufacturing an ink tank for a water-based marking pen, characterized by filling the ink tank with a certain amount of water-based ink so that it becomes an ink-unimpregnated part and the middle part becomes an ink-absorbing part.