JP7497287B2 - fountain pen - Google Patents

Description

The present invention relates to a fountain pen with ink grooves that supply ink to the writing area by capillary force.

Fountain pens with ink grooves that use capillary force to supply ink to the writing area are widely used. Among them, a writing instrument with three ink grooves instead of the usual one has been proposed (see, for example, Patent Document 1). With this writing instrument, more ink can be supplied to the writing area compared to a pen with one ink groove, so ink shortages can be prevented even when using a pen tip that writes bold characters.

Japanese Utility Model Application Publication No. 9-95083

However, because the cross-sectional area of the ink groove flow passage is very small, even if there are multiple ink grooves, the amount of ink that can be supplied to the front is naturally limited. As a result, it takes longer than necessary to go from a state in which there is no ink in the ink grooves, such as when starting to use the printer or after cleaning, to a state in which the ink in the ink storage area is filled up to the writing area at the front end and is ready for use.

The present invention aims to solve the above problems and provide a fountain pen that can efficiently supply ink in the ink storage area to the front end.

A fountain pen according to one embodiment of the present invention comprises:
A pen core partially covered with a pen tip,
a barrel having a neck portion that fits over the pen core and an ink storage area behind the fitting portion with the pen core;
a flow path provided in the fitting portion and communicating with the ink storage area;
an ink groove and a gas-liquid groove provided on an outer surface of the pen core at least forward of the flow path and communicating with the flow path;
Equipped with
Within a predetermined range from the rear end of the fitting portion, an outer surface of the pen core has a fitting surface that fits with an inner surface of the neck portion and a notched surface that is spaced apart from the inner surface of the neck portion,
the inner surface of the neck and the cutout surface spaced apart from each other define the flow passage, the flow passage having a cross-sectional area larger than a cross-sectional area of the ink groove;
The contact angle of the cutout surface is less than the contact angle of the inner surface of the neck portion to allow ink and air to flow through the flow passage.

The present invention provides a fountain pen that can efficiently supply ink from the ink storage area to the front end.

1 is a side cross-sectional view showing a schematic diagram of the overall structure of a fountain pen according to one embodiment of the present invention. 2 is an enlarged schematic cross-sectional view of the ink flow path shown in FIG. 1 . FIG. FIG. 2 is a perspective view showing a schematic diagram of an ink flow path shown in FIG. 1 . FIG. 4 is a perspective view showing a schematic view of ink flowing through the flow path shown in FIG. 3 .

Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. Note that the embodiment described below is for embodying the technical idea of the present invention, and the present invention is not limited to the following unless otherwise specified.
In each drawing, the same reference numerals may be used to designate components having the same function. The size and positional relationship of components shown in each drawing may be exaggerated for clarity. In this specification, "front" refers to the tip side of the writing instrument, and "rear" refers to the opposite side.

(Fountain pen according to one embodiment of the present invention)
First, an overview of a fountain pen according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a side cross-sectional view that shows a schematic view of the overall structure of a fountain pen according to one embodiment of the present invention.

The fountain pen 2 shown in Figure 1 comprises a nib 4, a pen core 10 partially covered by the nib 4, and a barrel 20 that fits with the pen core 10 at the neck 22 and has an ink storage area 30 inside. In a converter-type fountain pen 2 as shown in Figure 1, the ink storage area 30 located behind the fitting portion 50 where the pen core 10 and the neck 22 fit together corresponds to a storage portion that stores bottled ink sucked up by the converter. In a cartridge-type fountain pen, the ink storage area 30 corresponds to an ink cartridge.

The pen tip 4 has a pen point at the front end that comes into contact with the paper when writing, a slit that extends a specified distance rearward from the pen point, and a hole located approximately in the center of the pen tip 4. The area near the pen point is the writing area. As the pen tip 4 requires elasticity and corrosion resistance, the body is made of a gold alloy or special steel, and a wear-resistant alloy is used for the pen point that comes into contact with the paper.

The barrel 20 is composed of, for example, a neck 22 located at the front, a barrel 24 located in the center, and a tail plug 26 located at the rear. The neck 22 and barrel 24 are attached to each other in a detachable state by screwing or the like. An ink storage area 30 containing ink is located inside the barrel 20, mainly in the area of the barrel 24. Note that, for example, the barrel 24 and the tail plug 26 may be formed integrally. The barrel 20 may be formed, for example, from a resin material.

The pen tip 4 and the pen core 10 are overlapped and fitted into the tubular neck 22. At this time, the pen tip 4 is arranged to extend forward from the area where it overlaps with the pen core 10. The pen core 10 is arranged to extend rearward from the area where it overlaps with the pen tip 4. In other words, a part of the pen core 10 is covered by the pen tip 4. The area where the pen tip 4 and the pen core 10 overlap fits into the neck 22, resulting in a structure in which the pen tip 4 and the pen core 10 are firmly fixed to the front end of the barrel 20.

The pen core 10 is provided with an ink groove 12 for allowing the ink in the ink storage area 30 located at the rear end side to flow to the writing area at the front end of the pen tip 4. In addition, the pen core 10 is provided with an air-liquid groove 14 that communicates with the ink storage area 30 at the rear end and with the outside at the front end. If ink flows out of the ink storage area 30 through the ink groove 12, the ink storage area 30 will become negative pressure if left as is, and the ink will not be able to continue flowing. Therefore, the air-liquid groove 14 performs an air-liquid exchange that takes in air in the amount of ink that has flowed out, preventing the ink storage area 30 from becoming negative pressure and allowing the ink in the ink storage area 30 to be continuously supplied to the writing area.

Furthermore, when the ink groove 12 is filled with ink from the ink storage area 30 to the writing area at the front end and the writing area is not in contact with the paper surface or the like, ink flows from the ink storage area 30 etc. into the gas-liquid groove 14, blocking the air flow path in the gas-liquid groove 14. This makes it possible to prevent so-called ink dripping from the pen tip 4. The pen core 10 is also provided with a comb groove 16 that temporarily stores ink drawn from the ink storage area 30.
The pen core 10 can be made of a resin material, and when it is formed as an integral part, it can be easily cleaned.

In the fountain pen 2 according to this embodiment, the fitting portion 50 that fits with the neck portion 22 at the rear end of the pen core 10 is provided with a flow path 40 that communicates with the ink storage area 30 adjacent to the rear of the fitting portion 50. The ink groove 12 that extends from the rear end communicating with the ink storage area 30 to the front end side of the pen core 10 is also arranged in the area where the flow path 40 is provided and opens into the flow path 40. FIG. 1A shows the ink in the ink storage area 30 starting to flow forward in the flow path 40 (ink also flows in the ink groove 12), and FIG. 1B shows the ink further starting to flow forward in the ink groove 12 forward of the flow path 40. However, this is not limited to the case where the ink groove 12 is arranged in the area where the flow path 40 is provided. For example, the ink groove 12 may be provided only on the outer surface of the pen core 10 forward of the flow path 40. In that case, the rear end of the ink groove 12 communicates with the flow path 40. An air groove 14 is also provided on the outer surface of the pen core 10 at least in front of the flow passage 40 .
Cross section AA shows a cross section on the rear side of flow passage 40 , cross section BB shows a cross section on the front side of flow passage 40 , and cross section CC shows a cross section on the front side of flow passage 40 .
The cross-sectional area of the flow path 40 is larger than the cross-sectional area of the ink groove 12. As described later, by using the flow path 40 having a larger cross-sectional area, more ink in the ink storage region 30 can be efficiently supplied to the front side.

Flow Path According to One Embodiment of the Invention
Next, a flow path according to one embodiment of the present invention will be described with reference to Fig. 2 to Fig. 4. Fig. 2 is a cross-sectional view showing an enlarged schematic cross section of the ink flow path shown in Fig. 1. Fig. 3 is a perspective view showing a schematic perspective view of the ink flow path shown in Fig. 1. Fig. 4 is a perspective view showing ink flowing in the flow path shown in Fig. 3. Fig. 2 is a cross-sectional view of the flow path 40 as seen from the rear side. In Figs. 3 and 4, the upper side of the drawing corresponds to the rear side where the ink storage area 30 is located, and the lower side of the drawing corresponds to the front side.

In a predetermined range from the rear end of the fitting portion 50 where the pen core 10 and the neck portion 22 fit together, the outer surface of the pen core 10 has a fitting surface 10A that fits with the inner surface 22A of the neck portion 22, and a notched surface 42 that is spaced apart from the inner surface 22A of the neck portion 22. The inner surface 22A of the neck portion 22 and the notched surface 42 that are spaced apart from each other form a flow path 40 whose cross-sectional area is larger than the cross-sectional area of the ink groove 12.
The rear end of the flow passage 40 communicates with the adjacent ink storage area 30. The front end of the flow passage 40, where the cutout surface 42 terminates, communicates with the ink groove 12 and the gas-liquid groove 14 that open to the outer surface of the pen core 10.

In this embodiment, an ink groove 12 is formed on the cutout surface 42 and is connected to the ink groove 12 provided forward of the flow path 40. Furthermore, the gas-liquid groove 14 is formed to extend forward from the front end of the flow path 40. In this way, when an ink groove 12 is formed on the cutout surface 42 and is connected to the ink groove 12 provided forward of the flow path 40, ink in the ink storage area 30 can be efficiently supplied to the front using both the flow path 40 and the ink groove 12.

In this embodiment, the cross-sectional shape of the flow path 40 surrounded by the inner surface 22A of the neck 22 and the cutout surface 42 is approximately fan-shaped. However, this is not limited to this, and the cutout surface 42 can be shaped in any other shape. For example, it is also possible to form a flow path 40 that has an approximately U-shaped or C-shaped cross-sectional shape that opens to the outer surface of the pen core 10.

In this embodiment, the surface of the pen core 10 is subjected to a surface treatment to improve wettability. The notched surface 42 is also subjected to a surface treatment to improve wettability. Examples of surface treatments to improve wettability include blasting, plasma irradiation, surface treatment using gas, coating, etc. As a result, the contact angle of the notched surface 42 becomes smaller and the surface tension increases. On the other hand, the inner surface 22A of the neck 22 has not been subjected to a treatment to improve wettability. Therefore, the contact angle of the notched surface 42 is smaller than the contact angle of the inner surface 22A of the neck 22.

In this embodiment, the cutout surface 42 and the inner surface 22A of the neck 22, which are spaced apart from each other, form a flow path 40 whose cross-sectional area is larger than that of the ink groove 12, and the contact angle of the cutout surface 42 is smaller than the contact angle of the inner surface 22A of the neck 22. In a flow path 40 with a large cross-sectional area, the effect of surface tension on the ink surface is smaller, making the ink surface more likely to break up. In particular, when the contact angle of the cutout surface 42 and the contact angle of the inner surface 22A of the neck 22 are different, the ink surface is more likely to break up.

As a result, when the front end of the fountain pen 2 is positioned downward, as during writing, the balance between the pressure from the ink storage area 30 due to gravity and internal pressure and the atmospheric pressure from the outside through the gas-liquid groove 14 is lost. Therefore, in the area on the cutout surface 42 side where the contact angle is small, the ink overcomes the atmospheric pressure and flows from the top to the bottom in the flow path 40 (see the coloring representing the ink in FIG. 4 and the solid arrow indicating the ink flow). On the other hand, in the area on the inner surface 22A side of the neck 22, the ink overcomes the atmospheric pressure and becomes a passage for outside air flowing in through the gas-liquid groove 14 (see the dotted arrow in FIG. 4). As a result, a large amount of ink can be flowed forward using the flow path 40, and outside air can be taken in to prevent negative pressure on the ink storage area 30 side. Therefore, the ink in the ink storage area 30 can be efficiently sent to the front.

In this case, it is preferable that the contact angle of the cutout surface 42 is in the range of 20 degrees or more and 55 degrees or less, and the contact angle of the inner surface 22A of the neck portion 22 is in the range of 60 degrees or more and 80 degrees or less.
Although the contact angle varies slightly depending on the ink color, by setting the contact angle of the cutout surface 42 and the inner surface 22A of the neck portion 22 within this range for all standard inks, it is possible to reliably form a flow of ink flowing from the rear to the front and a flow of air flowing from the front to the rear within the flow path 40.

Furthermore, in the cross section of the flow passage 40, if the outer edge length of the flow passage 40 defined by the inner surface 22A of the neck portion 22 is L1 (see the dashed line in FIG. 2 ) and the outer edge length of the flow passage 40 defined by the cutout surface 42 is L2 (see the two-dot chain line in FIG. 2 ),
0.25≦L1/(L1+L2)≦0.5
It is preferable that the relationship be:
Although the ink groove 12 opens into the cutout surface 42, its size is very small, so the influence of the ink groove 12 is not taken into consideration when the outer edge length of the flow passage 40 defined by the cutout surface 42 is set to L2.
To express the above in another way, in the cross section of the flow path 40, it is preferable that the outer edge length (L1) of the flow path 40 defined by the inner surface 22A of the neck 22 is 25% or more and 50% or less of the total circumference length (L1 + L2) of the outer edge of the flow path 40 defined by the inner surface 22A of the neck 22 and the cutout surface 42.

If the outer edge length (L1) of the flow path 40 defined by the inner surface 22A is longer than 50% of the total circumference of the outer edge of the flow path 40 (L1+L2), the outer edge length L2 of the flow path 40 defined by the cutout surface 42 becomes relatively too small, and there is a risk that a sufficient amount of ink may not flow. On the other hand, if the outer edge length (L1) of the flow path 40 defined by the inner surface 22A is shorter than 25% of the total circumference of the outer edge of the flow path 40 (L1+L2), there is a possibility that a sufficient flow path for air to flow may not be secured, and there is a risk that ink may not flow smoothly.
As described above, by setting the length of the outer edge of the flow path 40 defined by the inner surface 22A of the neck portion 22 and the cutout surface 42 within the above range, it is possible to properly balance the supply of ink and the supply of outside air, thereby ensuring that ink is supplied to the front side efficiently.

In this case, as described above, when the cross-sectional shape of the flow path 40 surrounded by the inner surface 22A and the cutout surface 42 of the neck portion 22 is approximately fan-shaped, it is relatively easy to adjust the outer edge length (L1) of the flow path 40 defined by the inner surface 22A to 25% to 50% of the total circumference of the outer edge of the flow path 40 (L1 + L2) by adjusting the central angle of the fan shape.

As described above, the fountain pen 2 according to this embodiment has the following features:
A pen core 10 partially covered with a pen tip 4;
a barrel 20 that is fitted to the pen core 10 at a neck portion 22 and has an ink storage area 30 behind a fitting portion 50 with the pen core 10;
a flow path 40 provided in the fitting portion 50 and communicating with the ink storage area 30;
an ink groove 12 and a gas-liquid groove 14 which are provided on the outer surface of the pen core 10 at least on the front side of the flow path 40 and communicate with the flow path 40;
Equipped with
Within a predetermined range from the rear end of the fitting portion 50, the outer surface of the pen core 10 has a fitting surface 10A that fits with the inner surface 22A of the neck portion 22 and a notched surface 42 that is spaced apart from the inner surface 22A of the neck portion 22;
the spaced apart inner surface 22A of the neck 22 and the cutout surface 42 define a flow passage 40 having a cross-sectional area larger than the cross-sectional area of the ink groove 12;
The contact angle of the cutout surface 42 is smaller than the contact angle of the inner surface 22A of the neck portion 22 so that ink and air can flow through the flow passage 40.

As a result, when the front end side of the flow passage 40 is located lower than the rear end side,
The ink flowing in from the ink storage area 30 flows from the rear to the front along the cutout surface 42 and flows into the ink groove 12, while the outside air flowing in from the gas-liquid groove 14 flows from the front to the rear along the inner surface 22A of the neck portion 22 and flows into the ink storage area 30.

By using the flow path 40, the ink can be instantly moved to the front by gravity. This makes it possible to provide a fountain pen 2 that can efficiently supply ink in the ink storage area 30 to the front end.

The fountain pen according to the present invention is not limited to the above embodiment, but includes any other type having a hollow barrel. Although the embodiment and mode of implementation of the present invention have been described, the disclosed contents may vary in the details of the configuration, and the combination and order of elements in the embodiment and mode of implementation may be changed without departing from the scope and concept of the claimed invention.

2 Fountain pen 4 Pen tip 10 Pen core 10A Fitting surface 12 Ink groove 14 Gas-liquid groove 20 Barrel 22 Neck portion 22A Inner surface 24 Barrel 26 End cap 30 Ink storage area 40 Flow path 42 Notched surface 50 Fitting portion

Claims (6)

A pen core partially covered with a pen tip,
a barrel having a neck portion that fits over the pen core and an ink storage area behind the fitting portion with the pen core;
a flow path provided in the fitting portion and communicating with the ink storage area;
an ink groove and a gas-liquid groove provided on an outer surface of the pen core at least forward of the flow path and communicating with the flow path;
Equipped with
Within a predetermined range from the rear end of the fitting portion, an outer surface of the pen core has a fitting surface that fits with an inner surface of the neck portion and a notched surface that is spaced apart from the inner surface of the neck portion,
the inner surface of the neck and the cutout surface spaced apart from each other define the flow passage, the flow passage having a cross-sectional area larger than a cross-sectional area of the ink groove;
A fountain pen characterized in that the contact angle of the cutout surface is smaller than the contact angle of the inner surface of the neck portion, and ink and air flow through the flow path.
In a state in which the front end side of the flow path is located lower than the rear end side of the flow path,
A fountain pen as described in claim 1, characterized in that ink flowing in from the ink storage area flows from the rear to the front along the cutout surface and into the ink groove, and outside air flowing in from the air-liquid groove flows from the front to the rear along the inner surface of the neck and into the ink storage area.
A fountain pen as described in claim 1 or 2, characterized in that in the cross section of the flow passage, the outer edge length of the flow passage defined by the inner surface of the neck is 25% or more and 50% or less of the total circumference of the outer edge of the flow passage defined by the inner surface of the neck and the cutout surface.
A fountain pen as described in any one of claims 1 to 3, characterized in that the contact angle of the inner surface of the neck portion is in the range of 60 degrees or more and 80 degrees or less, and the contact angle of the cutout surface is in the range of 20 degrees or more and 55 degrees or less.
5. The fountain pen according to claim 1, wherein the cross-sectional shape of the flow passage surrounded by the inner surface of the neck and the cutout surface is substantially fan-shaped.
The fountain pen according to any one of claims 1 to 4, characterized in that an ink groove is formed on the cutout surface and is connected to the ink groove provided forward of the flow path.

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