Patent Description:
Conventionally, regarding such a direct liquid type of writing tool, for example, <CIT> has disclosed a direct liquid type of writing tool comprising: a pen tip; an ink absorbent body connected to a rear end of the pen tip; an ink tank arranged on a rear side of the ink absorbent body; and communicating tubes for connecting the ink tank and the ink absorbent body. In this direct liquid type of writing tool, two communicating tubes are provided in parallel with a space there between, and a front end of each of the two communicating tubes is opened. The ink absorbent body has a high-density portion, and a low-density portion rearward adjacently connected to the high-density portion. The front end of each of the communicating tubes and a rear end of the pen tip are connected to the high-density portion. In addition, <CIT> has disclosed that, when the front end of each of the communicating tubes is inserted from the rear end of the ink absorbent body, the front end of each of the communicating tubes presses the inside of the ink absorbent body frontward so that the high-density portion is formed in the ink absorbent body in the vicinity of the front end of each of the communicating tubes.

In the direct liquid type of writing tool disclosed in <CIT>, the front end of each of the communicating tubes has a sloped cut surface. The sloped cut surface (opening of the front end of the communicating tube) faces toward a central axis of the ink absorbent body. Thus, according to the inventors of the present patent application, in such a conventional direct liquid type of writing tool, the ink absorbent body is pressed too much in the vicinity of the front end of each of the communicating tubes, so that ink discharging performance from the pen tip may be deteriorated. In particular, this concern may be remarkable if the outer diameter of the barrel is made smaller to make the barrel thinner, and thus if the outer diameter of the ink absorbent body and the distance between the front-end openings of the communicating tubes are made smaller. <CIT> discloses a direct-fluid-supply writing implement comprising a pen-tip, an ink occlusion body connected to a rear end of the pen-tip, an ink tank that directly stores ink and is arranged at a rear of the ink occlusion body, a plurality of communication tubes that connects the ink tank to the ink occlusion body and a partition wall provided between the ink occlusion body and the ink tank, wherein forward end portions of the communication tubes are protruded forward from a front face of the partition wall, and are located inside the ink occlusion body, and wherein at least one of the communication tubes is provided such that a rear end of the communication tube is protruded backward from a rear face of the partition wall and is located inside the ink tank. <CIT> discloses an applicator comprising an application liquid reservoir in which filled application liquid is flowable, an applying body for applying the application liquid, an application liquid-occlusion body located between the application liquid reservoir and the applying body and designed to be impregnated with the application liquid, and a channel forming portion located between the application liquid reservoir and the occlusion body and having a channel in which the application liquid is flowable, wherein the channel forming portion has a protrusion, said protrusion having a cavity inside more than one communication openings communicated with the cavity.

The present invention has been made to solve the above conventional problems. The object of the present invention is to provide a direct liquid type of writing tool in which a proper high-density portion is formed in an ink absorbent body in a vicinity of a front end of each of communicating tubes so that sufficient ink discharging performance from a pen tip can be obtained, even if the distance between the front-end openings of the communicating tubes is made smaller.

In the present specification, the term "front" means the pen-tip side, and the term "rear" means the opposite side.

According to one aspect of the present invention a direct liquid type of writing tool of the present invention is defined in appended claim <NUM>.

According to the direct liquid type of writing tool, the front end of each of the communicating tubes has the sloped surface that goes radially inward toward the front side, and the opening of the front end of each of the communicating tubes faces radially outward. Thus, the ink absorbent body is not pressed too much in the vicinity of the front end of each of the communicating tubes, so that sufficient ink discharging performance from the pen tip can be obtained. In particular, according to the direct liquid type of writing tool, even if the outer diameter of the barrel is made smaller to make the barrel thinner, and thus even if the outer diameter of the ink absorbent body and the distance between the front-end openings of the communicating tubes are made smaller, the ink absorbent body is properly pressed in the vicinity of the front end of each of the communicating tubes, so that a proper high-density portion can be formed in the ink absorbent body in the vicinity of the front end of each of the communicating tubes. Thus, replacement of the ink and air can be smoothly conducted via the respective communicating tubes, so that the ink discharging performance from the pen tip is not deteriorated.

Preferably, in the direct liquid type of writing tool respective lateral walls of the communicating tubes are connected by a connecting part, and that a front-end region of the connecting part is located more frontward than the front-end opening of each of the communicating tubes.

According to this direct liquid type of writing tool, the respective lateral walls of the communicating tubes are connected by the connecting part, and the front-end region of the connecting part is located more frontward than the front-end opening of each of the communicating tubes. Thus, the ink absorbent body is more properly pressed in the vicinity of the front end of each of the communicating tubes, so that a proper high-density portion can be formed in the ink absorbent body in the vicinity of the front end of each of the communicating tubes.

Preferably, in the direct liquid type of writing tool the front-end region of the connecting part has a plurality of sloped surfaces that goes radially inward toward the front side, and that each of the sloped surfaces of the front-end region of the connecting part is continuously connected to the sloped surface at the front end of each of the communicating tubes.

According to this direct liquid type of writing tool, the front-end region of the connecting part has the plurality of sloped surfaces that goes radially inward toward the front side, and each of the sloped surfaces of the front-end region of the connecting part is continuously connected to the sloped surface at the front end of each of the communicating tubes. Thus, each of the communicating tubes can be more smoothly inserted into the ink absorbent body, so that a proper high-density portion can be formed in the ink absorbent body in the vicinity of the front end of each of the communicating tubes.

Preferably, in the direct liquid type of writing tool the front end of each of the communicating tubes has a planar sloped surface.

According to this direct liquid type of writing tool, the front end of each of the communicating tubes has the planar sloped surface. Thus, each of the communicating tubes can be more smoothly inserted into the ink absorbent body, so that a proper high-density portion can be formed in the ink absorbent body in the vicinity of the front end of each of the communicating tubes.

In addition, according to another aspect of the present invention a direct liquid type of writing tool of the present invention is defined in appended claim <NUM>.

According to this direct liquid type of writing tool, the front end of the joint communicating tube has such a configuration that each of the flow paths has the opening in the sloped surface facing toward the outer periphery side of the ink absorbent body, the joint communicating tube has the tip end region adjacent to the opening and extending more frontward than the opening, and the tip end region forms the pressing part configured to press the inside of the ink absorbent body. Thus, the ink absorbent body is pressed not too much in the vicinity of the tip end region of the joint communicating tube, so that sufficient ink discharging performance from the pen tip can be obtained. In particular, even if the outer diameter of the barrel is made smaller to make the barrel thinner, and thus even if the outer diameter of the ink absorbent body and the distance between the front-end openings of the joint communicating tube are made smaller, the ink absorbent body is properly pressed in the vicinity of the tip end region of the joint communicating tube, so that a proper (desired) high-density portion can be formed in the ink absorbent body in the vicinity of the tip end region of the joint communicating tube. As a result, replacement of the ink and air can be smoothly conducted via the respective flow paths, so that the ink discharging performance from the pen tip is not deteriorated.

For example, the front end of the joint communicating tube is configured to have a plurality of sloped surfaces, each of which faces toward the outer periphery side of the ink absorbent body, and each of the flow paths corresponds to each of the plurality of sloped surfaces, and has the opening in the corresponding sloped surface.

In this case, it is preferable that the number of the flow paths is two. If the number is two, one of them serves for supply of the ink, and the other of them serves for replacement by the air, so that the replacement of the ink and the air can be conducted more efficiently.

In addition, in this case, each of the sloped surfaces may be planar, convexly curved or concavely curved.

Alternatively, for example, the front end of the joint communicating tube has the shape of a rotating body rotationally symmetric around an axis. In more detail, the front end of the joint communicating tube may have the shape of a conical or frustoconical body. Alternatively, the front end of the joint communicating tube may have the shape of a part of a spherical body.

According to other aspects of the present invention othe direct types of writing tools are defined in appended claims <NUM> and <NUM>. A preferred embodiment is defined in appended claim <NUM>.

Accordingly, the front end of the communicating tube has such a configuration that each of the plurality of openings is opened in the sloped surface facing toward the outer periphery side of the ink absorbent body, the communicating tube has the tip end region adjacent to the opening and extending more frontward than the opening, and the tip end region forms the pressing part configured to press the inside of the ink absorbent body. Thus, the ink absorbent body is pressed not too much in the vicinity of the tip end region of the communicating tube, so that sufficient ink discharging performance from the pen tip can be obtained. In particular, even if the outer diameter of the barrel is made smaller to make the barrel thinner, and thus even if the outer diameter of the ink absorbent body and the distance between the front-end openings of the communicating tube are made smaller, the ink absorbent body is properly pressed in the vicinity of the tip end region of the communicating tube, so that a proper (desired) high-density portion can be formed in the ink absorbent body in the vicinity of the tip end region of the communicating tube. As a result, replacement of the ink and air can be smoothly conducted via the respective openings, so that the ink discharging performance from the pen tip is not deteriorated.

A direct liquid type of writing tool according to a first embodiment of the present invention is shown in <FIG>. <FIG> is a longitudinal section view of the direct liquid type of writing tool <NUM> according to the first embodiment of the present invention. <FIG> is an enlarged longitudinal section view of a main part of <FIG>. <FIG> is a cross section view taken along line A-A of <FIG>. <FIG> is a perspective view of the front end of the communicating tube shown in <FIG>.

As shown in <FIG>, the direct liquid type of writing tool <NUM> according to the present embodiment comprises: a pen tip <NUM>; an ink absorbent body <NUM> connected to a rear end of the pen tip <NUM>; an intermediate member <NUM> arranged on a rear side of the ink absorbent body; an ink tank <NUM> arranged on the rear side of the intermediate member <NUM>; a barrel <NUM> holding the pen tip <NUM> at a front end thereof; and a removable cap (not shown) provided on a front side of the pen tip <NUM>. The ink absorbent body <NUM>, the intermediate member <NUM> and a front portion of the ink tank <NUM> are contained in the barrel <NUM>. Hereinafter, each element is explained in detail.

The pen tip <NUM> of the present embodiment is a sticklike body made of synthetic resin fabric (such as polyester fabric, acrylic fabric, nylon fabric, etc.) by a resin processing. A front end of the pen tip <NUM> is ground into a shell-shape.

As shown in <FIG> and <FIG>, the ink absorbent body <NUM> of the present embodiment is a columnar processed body made of a bundle of synthetic resin fabric (such as polyester fabric). An outer peripheral surface of the ink absorbent body <NUM> is covered with a cylindrical outer skin made of synthetic resin. A rear end of the pen tip <NUM> is configured to be stuck and inserted into an axial center at a front end of the ink absorbent body <NUM>. Then, after the sticking and inserting, the rear end of the pen tip <NUM> is located inside the ink absorbent body <NUM>.

The barrel <NUM> of the present embodiment is a tubular member made of synthetic resin (such as polypropylene, polyethylene, etc.) by an injection molding. As shown in <FIG>, the barrel <NUM> consists of: a tapered part holding an outer peripheral surface of the pen tip <NUM>; and a main part connected to the tapered part on the rear side in which the ink absorbent body <NUM> and the intermediate member <NUM> are contained.

The ink tank <NUM> is removably attached to a rear-end opening of the barrel <NUM> (main part). Specifically, a male threaded portion 41a is formed on an front outer peripheral surface of the ink tank <NUM>, a female threaded portion <NUM> is formed on an inner peripheral surface of the rear-end opening of the barrel <NUM> (main part), and these threaded portions are engaged so that the front outer peripheral surface of the ink tank <NUM> and the inner peripheral surface of the rear-end opening of the barrel <NUM> (main part) are removably attached to each other.

The intermediate member <NUM> of the present embodiment is made of synthetic resin (such as polypropylene, polyethylene, etc.) by an injection molding. As shown in <FIG>, the intermediate member <NUM> consists of: a partition <NUM> separating the ink absorbent body <NUM> and the ink tank <NUM>; a plurality of (specifically, two connected) communicating tubes <NUM> projecting frontward from a front surface of the partition <NUM> and configured to be stuck into and connected to the ink absorbent body <NUM>; a connecting tube <NUM> projecting rearward from a rear surface of the partition <NUM> and configured to be fitted to a front-end opening of the ink tank <NUM>; and a fitting tubular part <NUM> projecting frontward from the front surface of the partition <NUM> and configured to be fitted on an inner peripheral surface of the barrel <NUM> (main part).

A space surrounded by the barrel <NUM>, the partition <NUM> and the fitting tubular part <NUM> forms an absorbent-body containing part, in which the ink absorbent body <NUM> is contained.

In addition, in the present embodiment, a stick part <NUM> projecting rearward is integrally formed at an axial center at the rear surface of the partition <NUM>. The stick part <NUM> is configured to push a plug <NUM> of the ink tank <NUM> rearward, which is explained below.

In the present embodiment, an inner surface of the connecting tube <NUM> and a front-end outer surface of the ink tank <NUM> are fitted to each other. However, an outer surface of the connecting tube <NUM> and a front-end inner surface of the ink tank <NUM> may be fitted to each other.

In the present embodiment, the partition <NUM> has the shape of a disk, and each of the respective communicating tubes <NUM>, the connecting tube <NUM> and the fitting tubular part <NUM> has a cylindrical shape.

In the present embodiment, the partition <NUM>, the respective communicating tubes <NUM>, the connecting tube <NUM>, the fitting tubular part <NUM> and the stick part <NUM> are integrally connected. That is, the partition <NUM>, the respective communicating tubes <NUM>, the connecting tube <NUM>, the fitting tubular part <NUM> and the stick part <NUM> are formed as a single piece, as the intermediate member <NUM>.

A flow path <NUM> is provided in an axial direction in each of the communicating tubes <NUM>. The flow path <NUM> is opened at both ends of the communicating tube <NUM>. A front end of each of the communicating tubes <NUM> is opened in the ink sorbent body <NUM>, and a rear end of each of the communicating tubes <NUM> is opened in the ink tank <NUM> on the rear side of the ink absorbent body <NUM>. The respective communicating tubes <NUM> are arranged in parallel between the ink absorbent body <NUM> and the ink tank <NUM>. That is, a plurality of (specifically, two) independent flow paths <NUM> are arranged in parallel between the ink absorbent body <NUM> and the ink tank <NUM>. The respective flow paths <NUM> of the present embodiment run through the partition <NUM>, inner than the connecting tube <NUM> but deviated (away) from the axial center. In the present embodiment, each flow path <NUM> of the communicating tube <NUM> has a circle shape in transverse section.

A sloped surface <NUM> is formed at the front end of each of the communicating tubes <NUM>. The sloped surface <NUM> faces toward the outer periphery side of the ink absorbent body <NUM>. That is, the sloped surface <NUM> has a shape such that the sloped surface <NUM> goes radially inward toward the front side. In other words, the sloped surface <NUM> has a shape such that the sloped surface <NUM> goes towards the axial center of the intermediate member <NUM> and the axial center of the ink absorbent body <NUM>, toward the front side.

The opening <NUM> of each communicating tube <NUM> (each flow path <NUM>) is formed in the sloped surface <NUM> facing toward the outer periphery side of the ink absorbent body <NUM> (facing radially outward). The opening <NUM> looks like an elliptical shape when viewed from directly above of the sloped surface <NUM>.

Specifically, the sloped surface <NUM> of the front end of the communicating tube <NUM> may be planar, convexly curved, concavely curved or the like. In the present embodiment, the planar sloped surface <NUM> is adopted.

In the present embodiment, respective lateral walls of the communicating tubes <NUM> are integrally connected by a connecting part <NUM>. A front end of the connecting part <NUM> is located more frontward than the respective openings of the communicating tubes <NUM>. A front-end region of the connecting part <NUM> also has a sloped surface <NUM> facing toward the outer periphery side of the ink absorbent body <NUM>, i.e., a sloped surface <NUM> goring radially inward toward the front side. In other words, the sloped surface <NUM> has a shape such that the sloped surface <NUM> goes towards the axial center of the intermediate member <NUM> and the axial center of the ink absorbent body <NUM>, toward the front side.

In the present embodiment, a plurality of (specifically, two) sloped surfaces <NUM> is formed at the connecting part <NUM>. Specifically, each of the plurality of sloped surface <NUM> may be planar, convexly curved, concavely curved or the like. In the present embodiment, the planar sloped surface <NUM> is adopted, and is smoothly continuous from the adjacent sloped surface <NUM> of the communicating tube <NUM>.

In the present embodiment, the plurality of (specifically, two) sloped surfaces <NUM> are adjacent to each other (intersect to form a certain angle (in this case, <NUM> degrees: see <FIG>)) on the opposite side with respect to the portions continuous from the sloped surfaces <NUM>, so that a ridge-like top portion <NUM> is formed at the foremost end (tip end) of the connecting part <NUM>. In the present embodiment, the top portion <NUM> of the connecting part <NUM> is located to intersect the axial center of the ink absorbent body <NUM>.

The front ends of the respective communicating tube <NUM> and the front end of the connecting part <NUM> are integrally stuck and inserted into the ink absorbent body <NUM>, frontward from the rear end of the ink absorbent body <NUM>, and positioned in the vicinity of the rear end of the pen tip <NUM>. When the front ends of the respective communicating tube <NUM> and the front end of the connecting part <NUM> are stuck and inserted into the ink absorbent body <NUM>, the front ends of the respective communicating tube <NUM> and the front end of the connecting part <NUM> push aside the fabric of the ink absorbent body <NUM> as well as press the fabric of the ink absorbent body <NUM> frontward. In particular, the tip end regions 52d of the communicating tubes <NUM> extending more frontward than the respective openings <NUM> and the region 61d of the connecting tube <NUM> extending more frontward than the respective openings <NUM> serve as the pressing part in cooperation. Because of this pressing function, fabric density of the ink absorbent body <NUM> in the vicinity of the front end of each of the communicating tubes <NUM> becomes higher than fabric density of the ink absorbent body <NUM> outside the vicinity of the front end of each of the communicating tubes <NUM>. That is, in the ink absorbent body <NUM>, a high-density portion <NUM> whose fabric density is higher is formed in the vicinity of the front end of each of the communicating tubes <NUM>, while a low-density portion <NUM> whose fabric density is lower is formed outside the vicinity of the front end of each of the communicating tubes <NUM> (see <FIG>).

A capillary force is greater in the high-density portion <NUM> in which the fabric density is higher, and is lower in the low-density portion <NUM> in which the fabric density is lower. Thus, the ink in the ink absorbent body <NUM> can be impregnated preferentially in the high-density portion <NUM>, rather than in the low-density portion <NUM>. The ink impregnated in the high-density portion <NUM> surely liquid-seals the respective openings <NUM> of the communicating tubes <NUM>. This effectively prevents the ink in the ink tank <NUM> from leaking from the pen tip <NUM> too much.

As described above, the front ends of the respective communicating tubes <NUM> are arranged away from the axial center of the ink absorbent body <NUM>. Preferably, the front ends of the respective communicating tubes <NUM> are arranged on the same circle whose center is the axial center of the ink absorbent body <NUM>, at regular circumferential intervals. In the present embodiment, since the number of the communicating tubes <NUM> is two, the two communicating tubes <NUM> are arranged at <NUM> degree positions symmetric with respect to the axial center of the ink absorbent body <NUM>. On the other hand, the pen tip <NUM> is located on the axial center of the ink absorbent body <NUM>. Thus, the front ends of the respective communicating tubes <NUM> are not directly connected to the rear end of the pen tip <NUM> (contactless), but can allow the ink to communicate with the pen tip <NUM> via the inside of the ink absorbent body <NUM>, in particular the high-density portion <NUM>. Herein, it is preferable that the front ends of the respective communicating tubes <NUM> are located more rearward than the rear end of the pen tip <NUM>.

As shown in <FIG>, the ink tank <NUM> of the present embodiment consists of: a tubular main part <NUM> having a front open end and a rear closed end; a tubular front part <NUM> fixed in an inner surface of the front open end of the main part <NUM>; and a plug <NUM> fitted in an inner surface of the tubular front part <NUM>. The main part <NUM> and the tubular front part <NUM> are made of synthetic resin by an injection molding. The plug <NUM> consists of a ball made of a metal or synthetic resin.

A male threaded portion 41a and a flange portion 41b positioned on the rear side of the male threaded portion 41a are integrally formed on an outer peripheral surface of the main part <NUM>. The male threaded portion 41a of the main part <NUM> is configured to engage with the female threaded portion <NUM> formed on the inner peripheral surface of the rear-end opening of the barrel <NUM>. When the ink tank <NUM> is fully connected, the flange portion 41b comes in contact with the rear end of the barrel <NUM>.

The ink tank <NUM> is closed by the plug <NUM> before the ink tank <NUM> is connected to the barrel <NUM>. When the ink tank <NUM> is used, the plug <NUM> is pushed and removed into the ink tank <NUM> by the stick part <NUM> of the intermediate member <NUM>, so that the ink tank <NUM> is opened. The ink <NUM> is directly stored in the ink tank <NUM>. The kind of the ink to be stored in the ink tank <NUM> may be any of water-based ink or oil-based ink.

The outer peripheral surface of the front-end opening of the ink tank <NUM> (in detail, the outer peripheral surface of the front end of the tubular front part <NUM>) is removably fitted in the inner peripheral surface of the connecting tube <NUM> of the intermediate member <NUM>. When the ink in the ink tank <NUM> is consumed so that the writing ability is lost, the used ink tank <NUM> is removed from the connecting tube <NUM>, and a new ink tank <NUM> in which the ink is full is fitted to the connecting tube <NUM>. Thus, the writing ability is revived. Herein, the front-end opening of the new ink tank <NUM> is closed by the plug <NUM>. When the front-end opening of the new ink tank <NUM> is fitted to the connecting tube <NUM>, the plug <NUM> is pushed and removed rearward by the stick part <NUM>, so that the new ink tank <NUM> is opened.

In the direct liquid type of writing tool <NUM> of the present embodiment the front end of each of the communicating tubes <NUM> has the sloped surface <NUM> that goes radially inward toward the front side, and the opening <NUM> of the front end of each of the communicating tubes <NUM> faces radially outward. Thus, the ink absorbent body <NUM> is not pressed too much in the vicinity of the front end of each of the communicating tubes <NUM>, so that sufficient ink discharging performance from the pen tip <NUM> can be obtained. In particular, according to the direct liquid type of writing tool <NUM> of the present embodiment, even if the outer diameter of the barrel <NUM> is made smaller to make the barrel thinner <NUM>, and thus even if the outer diameter of the ink absorbent body <NUM> and the distance between the front-end openings <NUM> of the communicating tubes <NUM> are made smaller, the ink absorbent body <NUM> is properly pressed in the vicinity of the front end of each of the communicating tubes <NUM>, so that a proper high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the front end of each of the communicating tubes <NUM>. Thus, replacement of the ink and air can be smoothly conducted via the respective communicating tubes <NUM>, so that the ink discharging performance from the pen tip <NUM> is not deteriorated.

The respective lateral walls of the communicating tubes <NUM> are connected by the connecting part <NUM>, and the front-end region of the connecting part <NUM> is located more frontward than the front-end opening <NUM> of each of the communicating tubes <NUM>. Thus, the ink absorbent body <NUM> is more properly pressed in the vicinity of the front end of each of the communicating tubes <NUM>, so that a proper high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the front end of each of the communicating tubes <NUM>.

The front-end region of the connecting part <NUM> has the plurality of sloped surfaces <NUM> that goes radially inward toward the front side, and each of the sloped surfaces <NUM> of the front-end region of the connecting part <NUM> is continuously connected to the sloped surface <NUM> at the front end of each of the communicating tubes <NUM>. Thus, each of the communicating tubes <NUM> can be more smoothly inserted into the ink absorbent body <NUM>, so that a proper high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the front end of each of the communicating tubes <NUM>.

The front end of each of the communicating tubes <NUM> has the planar sloped surface <NUM>. Thus, each of the communicating tubes <NUM> can be more smoothly inserted into the ink absorbent body <NUM>, so that a proper high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the front end of each of the communicating tubes <NUM>.

The front end of each of the communicating tubes <NUM> is configured to have the sloped surface <NUM> facing toward the outer periphery side of the ink absorbent body <NUM>, has the opening <NUM> in the sloped surface <NUM>, and has the tip end region 52d adjacent to the opening <NUM> and extending more frontward than the opening <NUM>, and the tip end region 52d forms the pressing part configured to press the inside of the ink absorbent body <NUM>. Thus, the ink absorbent body <NUM> is pressed not too much in the vicinity of the tip end region 52d of each of the communicating tubes <NUM>, so that sufficient ink discharging performance from the pen tip <NUM> can be obtained. In particular, even if the outer diameter of the barrel <NUM> is made smaller to make the barrel <NUM> thinner, and thus even if the outer diameter of the ink absorbent body <NUM> and the distance between the front-end openings <NUM> of the communicating tubes <NUM> are made smaller, the ink absorbent body <NUM> is properly pressed in the vicinity of the tip end region 52d of each of the communicating tubes <NUM>, so that a proper (desired) high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the tip end region 52d of each of the communicating tubes <NUM>. As a result, replacement of the ink and air can be smoothly conducted via the respective communicating tubes <NUM>, so that the ink discharging performance from the pen tip <NUM> is not deteriorated.

In addition, according to the direct liquid type of writing tool <NUM> of the present embodiment, since the respective lateral walls of the communicating tubes <NUM> are connected by the connecting part <NUM>, inserting the respective communicating tubes <NUM> into the ink absorbent body <NUM> becomes easier.

In addition, according to the direct liquid type of writing tool <NUM> of the present embodiment, since the front-end region 61d of the connecting part <NUM> extends more frontward than the opening <NUM> of each of the communicating tubes <NUM> so as to form the pressing part together with the tip end region 52d of each of the communicating tubes <NUM>, the ink absorbent body <NUM> is more properly pressed in the vicinity of the tip end region 52d of each of the communicating tubes <NUM>, so that a more proper high-density portion <NUM> is formed. As a result, the replacement of the ink and the air can be more smoothly conducted via the respective communicating tubes <NUM>.

In addition, according to the direct liquid type of writing tool <NUM> of the present embodiment, since the front-end region 61d of the connecting part <NUM> has one or more connecting-part sloped surfaces continuous from the sloped surface <NUM> of each of the communicating tubes <NUM>, insertion of the respective communicating tubes <NUM> into the ink absorbent body <NUM> can be more smoothly conducted. In addition, it is considered that this feature contributes to the fact that the ink absorbent body <NUM> is more properly pressed in the vicinity of the tip end region 52d of each of the communicating tubes <NUM> so that the more proper high-density portion <NUM> can be formed.

In addition, according to the direct liquid type of writing tool <NUM> of the present embodiment, since the number of the communicating tubes <NUM> is two, one of them serves for supply of the ink, and the other of them serves for replacement by the air, so that the replacement of the ink and the air can be conducted more efficiently.

In addition, in the present embodiment, it is important that the tip end regions 52d of the communicating tubes <NUM> extending more frontward than the respective openings <NUM> and the region 61d of the connecting tube <NUM> extending more frontward than the respective openings <NUM> serve as the pressing part in cooperation. In the present embodiment, the length L of the ridge-like top portion <NUM> (see <FIG>) is α mm, and the separation distance G of the two flow paths <NUM> (see <FIG>) is β mm. That is, it is important that at least the rectangular region of α mm × β mm when viewed from the front (when viewed in the arrow direction in <FIG>) achieves the pressing function effectively between the two openings <NUM>. The length L of the top portion <NUM> may be selected from a range of <NUM> to <NUM>, for example. The separation distance G between the two flow paths <NUM> may be selected from a range of <NUM> to <NUM>, for example.

As a supplemental explanation regarding the other sizes of the present embodiment, the diameter of the ink absorbent body <NUM> is about <NUM> to <NUM>, each flow path <NUM> has a circle shape in transverse section and the diameter <NUM> thereof (see <FIG>) is about <NUM> to <NUM>, the outer diameter D of each communicating tube <NUM> (see <FIG>) is about <NUM> to <NUM>, the distance a between the top portion <NUM> and the rear end of the pen tip <NUM> (see <FIG>) is about <NUM> to <NUM>.

In the above first embodiment, the lateral walls of the two communicating tubes <NUM> are connected by the connecting part <NUM>. However, adoptable is any manner in which the lateral walls are not connected. Such an embodiment is shown in <FIG> as a second embodiment.

<FIG> is an enlarged longitudinal section view of a main part of a direct liquid type of writing tool <NUM> according to the second embodiment of the present invention. <FIG> is a cross section view taken along line A-A of <FIG>. <FIG> is a perspective view of the front end of the communicating tube shown in <FIG>.

As shown in <FIG>, in the direct liquid type of writing tool <NUM> according to the second embodiment, the two communicating tubes <NUM> are not connected by a connecting part, but there is a slit-like gap <NUM> between them. The separation width S by the slit-like gap <NUM> is <NUM> to <NUM>.

The other structure of the second embodiment is substantially the same as that of the direct liquid type of writing tool <NUM> according to the first embodiment. In <FIG>, the same parts as those of the first embodiment are shown by the same reference numerals, and detailed explanation thereof is omitted. Respective sizes of the second embodiment are substantially the same as those of the first embodiment.

According to the second embodiment as well, substantially the same effects as those of the first embodiment can be achieved. That is, the ink absorbent body <NUM> is pressed not too much in the vicinity of the tip end region 52d of each of the communicating tubes <NUM>, so that sufficient ink discharging performance from the pen tip <NUM> can be obtained. In particular, even if the outer diameter of the barrel <NUM> is made smaller to make the barrel <NUM> thinner, and thus even if the outer diameter of the ink absorbent body <NUM> and the distance between the front-end openings <NUM> of the communicating tubes <NUM> are made smaller, the ink absorbent body <NUM> is properly pressed in the vicinity of the tip end region 52d of each of the communicating tubes <NUM>, so that a proper (desired) high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the tip end region 52d of each of the communicating tubes <NUM>. As a result, replacement of the ink and air can be smoothly conducted via the respective communicating tubes <NUM>, so that the ink discharging performance from the pen tip <NUM> is not deteriorated.

In the first embodiment, the lateral walls of the two communicating tubes <NUM> are connected by the connecting part <NUM>. However, adoptable is any manner in which they are integrally formed from the beginning, i.e., in which one joint communicating tube <NUM> having two flow paths <NUM> is provided, instead of the two communicating tubes <NUM> each of which has the flow path <NUM>. Such an embodiment is shown in <FIG> as a third embodiment.

<FIG> is a perspective view of a front end of a joint communicating tube <NUM> of a direct liquid type of writing tool according to the third embodiment of the present invention. <FIG> is a longitudinal section view of the front end of the joint communicating tube <NUM> shown in <FIG>.

As shown in <FIG>, the direct liquid type of writing tool according the third embodiment has the joint communicating tube <NUM> having two flow paths <NUM>, instead of the two communicating tubes <NUM> each of which has the flow path <NUM>.

The front end of the joint communicating tube <NUM> is located in the ink absorbent body <NUM>, and has such a configuration that each of the flow paths <NUM> has an opening <NUM> in a sloped surface <NUM> facing toward an outer periphery side of the ink absorbent body <NUM>. In addition, the joint communicating tube <NUM> has a tip end region <NUM> adjacent to the respective openings <NUM> and extending more frontward than the respective openings <NUM>. The tip end region <NUM> forms a pressing part configured to press inside of the ink absorbent body <NUM> when the joint communicating tube <NUM> is inserted frontward from a rear end of the ink absorbent body <NUM>.

Furthermore, in the third embodiment, the front end of the joint communicating tube <NUM> is configured to have the two sloped surfaces <NUM>, each of which faces toward the outer periphery side of the ink absorbent body <NUM>, and each of the two flow paths <NUM> corresponds to each of the two sloped surfaces and has the opening <NUM> in the corresponding sloped surface <NUM>. Then, the two sloped surfaces <NUM> are adjacent to each other (intersect to form a certain angle (in this case, <NUM> degrees: see <FIG>), so that a ridge-like top portion <NUM> is formed at the foremost end (tip end) of the joint communicating tube <NUM>. The top portion <NUM> of the third embodiment is also located to intersect the axial center of the ink absorbent body <NUM>.

The other structure of the third embodiment is substantially the same as that of the direct liquid type of writing tool <NUM> according to the first embodiment. In <FIG>, the same parts as those of the first embodiment are shown by the same reference numerals, and detailed explanation thereof is omitted. Respective sizes of the third embodiment are substantially the same as those of the first embodiment.

According to the third embodiment as well, substantially the same effects as those of the first embodiment can be achieved. That is, the ink absorbent body <NUM> is pressed not too much in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>, so that sufficient ink discharging performance from the pen tip <NUM> can be obtained. In particular, even if the outer diameter of the barrel <NUM> is made smaller to make the barrel <NUM> thinner, and thus even if the outer diameter of the ink absorbent body <NUM> and the outer diameter of the joint communicating tube <NUM> are made smaller, the ink absorbent body <NUM> is properly pressed in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>, so that a proper (desired) high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>. As a result, replacement of the ink and air can be smoothly conducted via the respective flow paths <NUM>, so that the ink discharging performance from the pen tip <NUM> is not deteriorated.

In the first and third embodiments, the ridge-like top portion <NUM>, <NUM> is formed at the foremost end (tip end) of the connecting part <NUM> or the joint communicating tube <NUM>. Adoptable is any manner in which no ridge-like top portion is formed. Such an embodiment is shown in <FIG> as a fourth embodiment.

<FIG> is a perspective view of a front end of a joint communicating tube <NUM> of a direct liquid type of writing tool according to the fourth embodiment of the present invention. <FIG> is a longitudinal section view of the front end of the joint communicating tube <NUM> shown in <FIG>.

As shown in <FIG>, the front end of the joint communicating tube <NUM> is located in the ink absorbent body <NUM>, and has such a configuration that each of the flow paths <NUM> has an opening <NUM> in a sloped surface <NUM> facing toward an outer periphery side of the ink absorbent body <NUM>. In addition, the joint communicating tube <NUM> has a tip end region <NUM> adjacent to the respective openings <NUM> and extending more frontward than the respective openings <NUM>. The tip end region <NUM> forms a pressing part configured to press inside of the ink absorbent body <NUM> when the joint communicating tube <NUM> is inserted frontward from a rear end of the ink absorbent body <NUM>.

In addition, as shown in <FIG>, in the direct liquid type of writing tool according to the fourth embodiment as well, the front end of the joint communicating tube <NUM> is configured to have the two sloped surfaces <NUM>, each of which faces toward the outer periphery side of the ink absorbent body <NUM>, and each of the two flow paths <NUM> corresponds to each of the two sloped surfaces <NUM> and has the opening <NUM> in the corresponding sloped surface <NUM>.

However, the two sloped surfaces <NUM> are on a smoothly continuous convex curved surface having the same curvature, and no ridge-like top portion is formed at the foremost end (tip end) of the joint communicating tube <NUM>. The curvature radius of the continuous two sloped surfaces <NUM> (see <FIG>) is for example <NUM>.

The other structure of the fourth embodiment is substantially the same as that of the direct liquid type of writing tool according to the third embodiment. In <FIG>, the same parts as those of the third embodiment are shown by the same reference numerals, and detailed explanation thereof is omitted. Respective sizes of the fourth embodiment are substantially the same as those of the first embodiment.

According to the fourth embodiment as well, substantially the same effects as those of the third embodiment can be achieved. That is, the ink absorbent body <NUM> is pressed not too much in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>, so that sufficient ink discharging performance from the pen tip <NUM> can be obtained. In particular, even if the outer diameter of the barrel <NUM> is made smaller to make the barrel <NUM> thinner, and thus even if the outer diameter of the ink absorbent body <NUM> and the outer diameter of the joint communicating tube <NUM> are made smaller, the ink absorbent body <NUM> is properly pressed in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>, so that a proper (desired) high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>. As a result, replacement of the ink and air can be smoothly conducted via the respective flow paths <NUM>, so that the ink discharging performance from the pen tip <NUM> is not deteriorated.

As a shape of the front end of the joint communicating tube, adoptable is any shape of a rotating body rotationally symmetric around an axis. Such an embodiment is shown in <FIG> as a fifth embodiment.

<FIG> is a perspective view of a front end of a joint communicating tube <NUM> of a direct liquid type of writing tool according to the fifth embodiment of the present invention. <FIG> is a longitudinal section view of the front end of the joint communicating tube <NUM> shown in <FIG>.

Then, as shown in <FIG>, in the direct liquid type of writing tool according to the fifth embodiment, the front end of the joint communicating tube <NUM> is configured to have a conical sloped surface <NUM>, two flow paths <NUM> are arranged in pair on diametrically opposite sides in cross section, and each flow path <NUM> has the opening <NUM> in the conical sloped surface <NUM>. In the conical shape of the fifth embodiment, as shown in <FIG>, an angle formed by the conical genetratrixes in a section including the top point <NUM> is about <NUM> degrees.

As a supplemental explanation regarding the other sizes of the present embodiment, the diameter of the ink absorbent body <NUM> is about <NUM> to <NUM>, the outer diameter D of the joint communicating tube <NUM> is about <NUM> to <NUM>, each flow path <NUM> has a circle shape in transverse section and the diameter d thereof is about <NUM> to <NUM>, and the distance a between the top point <NUM> and the rear end of the pen tip <NUM> (see <FIG>) is about <NUM> to <NUM>. In addition, the separation distance G of the two flow paths <NUM> is γ mm. That is, at least the rectangular region of γ mm × γ mm when viewed from the front (when viewed in the arrow direction in <FIG>) achieves the pressing function effectively between the two openings <NUM>. In the present embodiment, the separation distance G between the two flow paths <NUM> may be selected from a range of <NUM> to <NUM>, for example.

The other structure of the fifth embodiment is substantially the same as that of the direct liquid type of writing tool according to the third embodiment. In <FIG>, the same parts as those of the third embodiment are shown by the same reference numerals, and detailed explanation thereof is omitted.

According to the fifth embodiment as well, substantially the same effects as those of the third embodiment can be achieved. That is, the ink absorbent body <NUM> is pressed not too much in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>, so that sufficient ink discharging performance from the pen tip <NUM> can be obtained. In particular, even if the outer diameter of the barrel <NUM> is made smaller to make the barrel <NUM> thinner, and thus even if the outer diameter of the ink absorbent body <NUM> and the outer diameter of the joint communicating tube <NUM> are made smaller, the ink absorbent body <NUM> is properly pressed in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>, so that a proper (desired) high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>. As a result, replacement of the ink and air can be smoothly conducted via the respective flow paths <NUM>, so that the ink discharging performance from the pen tip <NUM> is not deteriorated.

In the present embodiment, the top point <NUM> is formed at the foremost end (tip end) of the joint communicating tube <NUM>. However, adoptable are any manner in which the top point is rounded and the vicinity of the foremost end (tip end) is a part of a spherical surface, and any manner in which the front end of the joint communicating tube <NUM> has a frustoconical shape.

As a shape of the front end of the joint communicating tube, a part of a spherical surface is adoptable. A part of a spherical surface is also a shape of a rotating body rotationally symmetric around an axis. Such an embodiment is shown in <FIG> as a sixth embodiment.

<FIG> is a perspective view of a front end of a joint communicating tube <NUM> of a direct liquid type of writing tool according to the sixth embodiment of the present invention. <FIG> is a longitudinal section view of the front end of the joint communicating tube <NUM> shown in <FIG>.

Then, as shown in <FIG>, in the direct liquid type of writing tool according to the sixth embodiment, the front end of the joint communicating tube <NUM> is configured to have a partial spherical sloped surface <NUM>, two flow paths <NUM> are arranged in pair on diametrically opposite sides in cross section, and each flow path <NUM> has the opening <NUM> in the partial spherical sloped surface <NUM>. The curvature radius of the partial spherical shape of the sixth embodiment (see <FIG>) is for example <NUM>.

The other structure of the sixth embodiment is substantially the same as that of the direct liquid type of writing tool according to the fifth embodiment. In <FIG>, the same parts as those of the fifth embodiment are shown by the same reference numerals, and detailed explanation thereof is omitted. Respective sizes of the sixth embodiment are substantially the same as those of the fifth embodiment.

According to the sixth embodiment as well, substantially the same effects as those of the fifth embodiment can be achieved. That is, the ink absorbent body <NUM> is pressed not too much in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>, so that sufficient ink discharging performance from the pen tip <NUM> can be obtained. In particular, even if the outer diameter of the barrel <NUM> is made smaller to make the barrel <NUM> thinner, and thus even if the outer diameter of the ink absorbent body <NUM> and the outer diameter of the joint communicating tube <NUM> are made smaller, the ink absorbent body <NUM> is properly pressed in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>, so that a proper (desired) high-density portion <NUM> can be formed in the ink absorbent body <NUM> in the vicinity of the tip end region <NUM> of the joint communicating tube <NUM>. As a result, replacement of the ink and air can be smoothly conducted via the respective flow paths <NUM>, so that the ink discharging performance from the pen tip <NUM> is not deteriorated.

In the present embodiment, the sloped surface <NUM> at the front end of the joint communicating tube <NUM> is a partial spherical surface having the uniform curvature radius, but the curvature radius may be different between in an area including the axil center and in another peripheral area (in some cases, and one or more additional intermediate areas).

In the direct liquid type of writing tool according to each of the above embodiments, the flow paths <NUM> may be communicated with each other in the middle thereof, which is also adoptable as an embodiment of the present invention. For example, regarding the direct liquid type of writing tools according to the third to sixth embodiments, variations are shown in <FIG>, in which the two flow paths <NUM> are communicated with each other via a communicating path <NUM>. <FIG> are longitudinal section views of the front ends of the respective variations of the joint communicating tube <NUM>' to <NUM>'.

In extreme cases, although the number of openings is two, the two flow paths <NUM> may be integral in the whole area other than the openings. Regarding these cases, it can be said that the number of communicating tube is one. Such variations are shown in <FIG> are longitudinal section views of the front ends of the respective variations of the communicating tube <NUM>" to <NUM>".

Each variation of the direct liquid type of writing tool comprises: a pen tip <NUM>; a columnar ink absorbent body <NUM> connected to a rear end of the pen tip <NUM>; an ink tank <NUM> arranged on a rear side of the ink absorbent body <NUM>; and a communicating tube <NUM>" to <NUM>" for connecting the ink absorbent body <NUM> and the ink tank <NUM>; wherein a front end of the communicating tube <NUM>" to <NUM>" is located in the ink absorbent body <NUM>, and has such a configuration that each of two openings <NUM> is opened in a sloped surface <NUM> to <NUM> facing toward an outer periphery side of the ink absorbent body <NUM>, the communicating tube <NUM>" to <NUM>" has a tip end region <NUM> to <NUM> adjacent to the respective openings <NUM> and extending more frontward than the respective openings <NUM>, and the tip end region <NUM> to <NUM> forms a pressing part configured to press inside of the ink absorbent body <NUM> when the communicating tube <NUM>" to <NUM>" is inserted frontward from a rear end of the ink absorbent body <NUM>.

Claim 1:
A direct liquid type of writing tool (<NUM>) comprising:
a pen tip (<NUM>);
a columnar ink absorbent body (<NUM>) connected to a rear end of the pen tip (<NUM>);
an ink tank (<NUM>) arranged on a rear side of the ink absorbent body (<NUM>); and
a plurality of communicating tubes (<NUM>) for connecting the ink absorbent body (<NUM>) and the ink tank (<NUM>);
wherein
a front end of each of the communicating tubes (<NUM>) is located in the ink absorbent body (<NUM>), and is configured to have a sloped surface (<NUM>),
each of the communicating tubes (<NUM>) has an opening (<NUM>) in the sloped surface (<NUM>) at the front end,
each of the communicating tubes (<NUM>) has a tip end region (52d) adjacent to the opening (<NUM>) and extending more frontward than the opening (<NUM>), and
the tip end region (52d) forms a pressing part configured to press inside of the ink absorbent body (<NUM>) when each of the communicating tubes (<NUM>) is inserted frontward from a rear end of the ink absorbent body (<NUM>), characterized in that each sloped surface (<NUM>) faces toward an outer periphery side of the ink absorbent body (<NUM>) and goes radially inward toward the front side, and the opening (<NUM>) of the front end of each of the communicating tubes (<NUM>) faces radially outward.