JP4848067B2 - Direct liquid writing instrument - Google Patents

Description

  The present invention relates to a direct liquid writing instrument in which ink is directly stored in an ink tank and an ink occlusion body is interposed between the ink tank and a pen tip. In the present invention, “front” refers to the pen tip side, and “rear” refers to the ink tank side.

Conventionally, in this type of direct liquid writing instrument, Patent Literature 1 and Patent Literature 2 include a pen tip, an ink occlusion body connected to the rear end of the pen nib, and a rear side of the ink occlusion body, There has been disclosed a direct liquid type writing instrument comprising an ink tank for directly storing ink and a plurality of communication pipes connecting between the ink tank and the ink occlusion body.

JP 2006-212884 A JP 2006-240281 A

The conventional direct liquid writing instrument has a structure that can sufficiently prevent the ink from leaking to the outside even when the pressure in the ink tank rises due to a temperature change or the like under a normal environment such as a room. However, the conventional direct liquid type writing instrument does not leak ink or blow out ink from the pen tip side due to a sudden pressure change in the ink tank under an environment where the temperature changes drastically such as outdoors or under reduced pressure conditions such as in an aircraft. There was room for improvement in terms of prevention.

The present invention solves the above-mentioned conventional problems, and provides a direct liquid writing instrument that can sufficiently prevent ink leakage and ink blowing from the pen tip side even when the pressure in the ink tank suddenly changes. It is something to try.

The first invention of the present application is a pen tip 2, an ink occlusion body 3 connected to the rear end of the nib 2, and an ink tank which is disposed behind the ink occlusion body 3 and directly stores ink 8. 7 and a plurality of communication pipes 52 connecting between the ink tank 7 and the ink storage body 3, and each of the communication pipes 52 is provided with a flow passage 52a, and each of the flow passages 52a includes A direct liquid type writing instrument which is opened at the front end and the rear end of each communication pipe 52 and the front end of each communication pipe 52 is located inside the ink storage body 3, and the flow path of each communication pipe 52 It is a requirement that a constricted portion 55 for reducing the cross-sectional area of the flow passage 52a is provided on the inner surface of the flow passage 52a, and that the cross-sectional area of the constricted portion 55 is set smaller than the cross-sectional area of the flow passage 52a other than the constricted portion 55.

The direct liquid writing instrument 1 according to the first aspect of the present invention is provided with a throttle portion 55 that reduces the cross-sectional area of the flow passage 52a on the inner surface of the flow passage 52a of each of the communication pipes 52. When the pressure in the ink tank 7 changes abruptly by setting it smaller than the cross-sectional area of the flow passage 52 a other than the throttle portion 55, the ink 8 in the ink tank 7 gains momentum through the flow passage 52 a in the communication pipe 52. Even if the ink is well extruded in the direction of the ink occlusion body 3, the flow rate of the ink can be suppressed by the squeezing portion 55, and the extruded ink can be impregnated in a wide range of the ink occlusion body 3. As a result, it is possible to sufficiently prevent the ink pushed out from the ink tank 7 from leaking out and blowing out through the ink occlusion body 3.

Note that the case where the pressure in the ink tank changes suddenly means that, for example, after the cap is mounted on the pen tip side in a low temperature environment, the ink tank side is pressurized in a high temperature environment. Or the case where the cap is removed from the nib side in a decompressed state such as in an airplane after the cap is attached to the nib side at 1 atmospheric pressure on the ground.

Each of the communication pipes 52 has a function of supplying the ink 8 in the ink tank 7 into the ink storage body 3 and a function of supplying outside air into the ink tank 7.

When supplying the ink 8 in the ink tank 7 to the ink occlusion body 3 when the direct liquid type writing instrument 1 of the first invention is placed in the downward direction, the ink 8 in the ink tank 7 is caused by gravity. The ink occlusion body 3 is supplied through at least one communication pipe 52 and impregnated inside the ink occlusion body 3. At the same time, outside air is taken into the ink tank 7 through the other communication pipe 52. When the ink impregnated inside the ink occlusion body 3 reaches a certain amount, the front end opening of the other communication pipe 52 that has taken in the outside air is liquid-sealed by the impregnation ink and temporarily closed. The supply of outside air into the tank 7 is stopped. At the same time, the ink supply from the ink tank 7 to the ink occluding body 3 by the communication pipe 52 that has been supplying the ink is also stopped. As a result, each front end opening of the communication pipe 52 is in a liquid-sealed state temporarily. The ink tank 7 is closed, and the ink outflow from the ink tank 7 and the air inflow into the ink tank 7 (that is, replacement of ink and air) are stopped.

Further, the direct liquid writing instrument 1 according to the first aspect of the present invention is an excess ink that is pushed out from the ink tank 7 when the pressure in the ink tank 7 increases due to a temperature rise or the like in a normal environment such as a room. Is supplied to the inside of the ink storage body 3 through the communication pipe 52 and is temporarily impregnated inside the ink storage body 3. The direct liquid writing instrument 1 according to the first aspect of the present invention is an ink impregnated in the ink occlusion body 3 when the pressure in the ink tank 7 decreases due to a temperature drop or the like under a normal environment such as a room. Is returned to the ink tank 7 through the communication pipe 52. As a result, when the pressure in the ink tank 7 changes in a normal environment such as a room, the excess ink in the ink tank 7 is temporarily absorbed by the ink storage 3 appropriately, and then the excess ink is removed from the ink tank. It can be properly returned to the tank 7. As a result, the ink can be sufficiently prevented from leaking to the outside.

According to a second invention of the present application, in the first invention, the throttle portion 55 is provided at the front end of each of the communication pipes 52, and each of the flow passages 52 a is formed only by the front end opening of each of the communication pipes 52. It is necessary to communicate with the body 3.

In the direct liquid writing instrument 1 according to the second aspect of the present invention, the throttle portion 55 is provided at the front end of each communication pipe 52, so that ink is smoothly supplied from the ink tank 7 to the ink occlusion body 3 during normal writing. can do. Further, in the direct liquid writing instrument 1 according to the second aspect of the invention, each flow passage 52a communicates with the ink storage body 3 only at each front end opening of the communication pipe 52, so that the pressure in the ink tank 7 is rapidly increased. If the ink in the ink tank 7 is forced out through the flow passage 52a in the communication pipe 52 in the direction of the ink occlusion body 3, the ink flow rate can be appropriately suppressed by the squeezing portion 55. The extruded ink can be reliably impregnated in a wide range of the ink occlusion body 3. If each of the flow passages 52a communicates with the ink occlusion body 3 at a location other than the front end of the communication pipe 52, there is a possibility that a sufficient ink flow rate suppressing effect at the throttle portion 55 cannot be obtained.

According to a third invention of the present application, in the first or second invention, a cross-sectional area of the throttle portion 55 is in a range of 0.15 mm ² to 5 mm ² (preferably 0.5 mm ^{2 to} 4 mm ² ). As a requirement.

The direct liquid writing instrument 1 according to the third aspect of the present invention is an ink that passes through the flow passage 52a when the pressure in the ink tank 7 changes suddenly by setting the cross-sectional area of the squeezed portion 55 within the above range. The flow rate can be reliably suppressed, and sufficient ink can be supplied during writing. When the cross-sectional area of the narrowed portion 55 is less than 0.15 mm ² (0.15 square millimeters), the ink supply amount from the ink tank 7 to the ink storage body 3 at the time of writing may be insufficient. Further, when the cross-sectional area of the narrowed portion 55 exceeds 5 mm ² (5 square millimeters), the ink flow rate may not be sufficiently suppressed by the narrowed portion 55 when the pressure in the ink tank 7 changes suddenly. .

According to a fourth invention of the present application, in the first to third inventions, the volume V2 of the ink occlusion body 3 is 40% or more of the volume V1 of the space formed by the ink tank 7 and the respective communication pipes 52. It is a requirement that it is set to (preferably 50% or more).

In the direct liquid writing instrument 1 according to the fourth aspect of the present invention, the pressure in the ink tank 7 is rapidly changed by setting the ratio of the volume V2 to the volume V1 to 40% or more (preferably 50% or more). In this case, even if the ink 8 in the ink tank 7 is pushed out through the communication pipe 52, the ink 8 is properly impregnated in the ink storage 3. Thereby, it is possible to sufficiently prevent the ink from leaking out or blowing out from the pen tip 2 side.

When the ratio of the volume V2 to the volume V1 is less than 40%, there is a possibility that a sufficient amount of ink from the ink tank 7 cannot be held by the ink occlusion body 3 when the pressure in the ink tank 7 changes abruptly. .

In the fourth invention, the volume V2 is preferably set to 70% or less of the volume V1. It is effective to set the ratio of the volume V2 to the volume V1 in the range of 40% to 70%, preferably in the range of 50% to 70%. When the ratio of the volume V2 to the volume V1 exceeds 70%, the amount of ink stored in the ink tank 7 becomes excessively small and the writable distance becomes short, which is not practical.

Note that the volume V1 of the space formed by the ink tank 7 and each of the communication pipes 52 is the volume in the ink tank 7 (however, when the connection portion 53 has a space, the space is included). The total volume of the communication pipes 52 is referred to. The volume V2 of the ink occlusion body 3 refers to the volume of the ink occlusion body 3 excluding the pen tip 2 and the portion of each communication pipe 52 inserted into the ink occlusion body 3.

According to a fifth invention of the present application, in the first to fourth inventions, the volume V3 of the ink occlusion body 3 in front of the front end of the communication pipe 52 positioned in the foremost position among the plurality of communication pipes 52, The requirement is that it is set to 10% or more (preferably 15% or more) of the volume V1 of the space formed by the ink tank 7 and each of the communication pipes 52.

In the direct liquid writing instrument 1 according to the fifth aspect of the present invention, the pressure in the ink tank 7 has suddenly changed by setting the ratio of the volume V3 to the volume V1 to 10% or more (preferably 15% or more). In this case, even if ink is blown forward from the front end opening of the communication pipe 52, the ink can be properly held in the ink occlusion body 3, and ink leakage to the outside and ink blowing can be sufficiently prevented.

In the fifth aspect of the invention, it is effective to set the ratio of the volume V3 to the volume V1 to 40% or less. Thereby, an increase in the cost of the ink occlusion body 3 can be suppressed. It is effective to set the ratio of the volume V3 to the volume V1 in the range of 15% to 40%, preferably in the range of 20% to 35%.

The volume V3 of the ink storage body 3 in front of the front end of the communication pipe 52 located in the foremost position among the plurality of communication pipes 52 is the pen in front of the front end of the communication pipe 52 located in the foremost position. The volume of the ink occlusion body 3 excluding the portion inserted into the ink occlusion body 3 of the tip 2 is said. The position of the front end of each of the communication pipes 52 in the axial direction may be either coincident or different. When the axial positions of the front ends of the communication pipes 52 coincide with each other, the volume V3 is inserted into the ink occlusion body 3 of the nib 2 in front of any front end of the communication pipe 52. This refers to the volume of the ink occlusion body 3 excluding the portion.

According to a sixth aspect of the present invention, in the first to fifth aspects of the present invention, the volume V4 of the ink occlusion body 3 at the rear of the front end of the communication pipe 52 located at the rearmost position among the plurality of communication pipes 52, The requirement is that it is set to 10% or more (preferably 15% or more) of the volume V1 of the space formed by the ink tank 7 and each of the communication pipes 52.

In the direct liquid writing instrument 1 according to the sixth aspect of the invention, the ratio of the volume V4 to the volume V1 is set to 10% or more (preferably 15% or more), whereby the pressure in the ink tank 7 changes abruptly. In this case, even if ink blows out backward from the front end opening of the communication pipe 52, the ink can be properly held in the ink occlusion body 3, and ink leakage to the outside and ink blowing out can be sufficiently prevented.

In the sixth aspect of the invention, it is effective to set the ratio of the volume V4 to the volume V1 to 40% or less. Thereby, since the insertion length of the communication pipe 52 into the ink storage body 3 is properly maintained, there is no possibility that the assembling property between the communication pipe 52 and the ink storage body 3 is lowered, and the ink storage body 3 The increase in cost can be suppressed. It is effective to set the ratio of the volume V4 to the volume V1 in the range of 15% to 40%, preferably in the range of 20% to 35%.

In addition, the volume V4 of the ink storage body 3 behind the front end of the communication pipe 52 located at the rearmost position among the plurality of communication pipes 52 is respectively the rear of the front end of the communication pipe 52 located at the rearmost position. The volume of the ink occlusion body 3 excluding the portion inserted into the ink occlusion body 3 of the communication pipe 52. The position of the front end of each of the communication pipes 52 in the axial direction may be either coincident or different. When the axial positions of the front ends of the communication pipes 52 coincide with each other, the volume V4 is inserted into the ink storage body 3 of each communication pipe 52 behind the front end of any one of the communication pipes 52. It means the volume of the ink occlusion body 3 excluding the portion to be formed.

(Communication pipe)
In the present invention, the communication pipe 52 is preferably made of synthetic resin or metal in that it has a certain rigidity. Further, the cross-sectional shape of the outer peripheral surface and the inner peripheral surface of the communication pipe 52 may be any of, for example, a circle, an ellipse, or a polygon such as a triangle or a quadrangle. Moreover, the number of the said communication pipe | tubes 52 should just be two or more (namely, 2 or more), for example, 2, 3, 4, 5 or 6 etc. are mentioned.

Each of the communication pipes 52 extends in the front-rear direction, and a flow passage 52a is provided through each of the communication pipes 52 in the front-rear direction. That is, each of the communication pipes 52 includes openings at both ends (front end and rear end).

Further, the plurality of communication pipes 52 only need to have a structure in which a plurality of independent flow passages 52a are formed in parallel therein. For example, each of the communication pipes 52 is separated in the radial direction, The structure which the side wall of this communication pipe 52 mutually connected, the structure which has arrange | positioned the small diameter communication pipe inside the large diameter communication pipe, etc. are mentioned.

Further, it is preferable that the front ends of the communication pipes 52 are located at equal intervals on the same circumference with the nib 2 as the center. Further, the front end of each of the communication pipes 52 may be opened forward in the axial direction or may be opened outward in the radial direction. Examples of the shape of the front end of each of the communication pipes 52 include an inclined cut surface, a vertical surface, a conical surface, and a convex curved surface. The rear end of each of the communication pipes 52 may open rearward in the axial direction or may open outward in the radial direction. The rear end of each of the communication pipes 52 may protrude rearward from the rear surface of the partition wall 51.

(Ink storage)
In the present invention, the ink occlusion body 3 may be made of a member having continuous pores that can be impregnated with ink (that is, a porous material). Resin processed body, felt resin processed body, felt needle punch processed body, synthetic resin open cell body, and the like. In addition, the ink occlusion body 3 may be configured to have an outer skin made of a synthetic resin film or the like on its outer peripheral surface. The ink occlusion body 3 may be a single member or a plurality of members having different capillary forces.

(Nib)
In the present invention, the nib 2 is, for example, a fiber bundle resin processed body, a fiber bundle heat fusion processed body, a felt processed body, a pipe-shaped pen body, and a fountain pen type plate-shaped pen body having a slit at the tip. A brush pen body, a porous foam of a synthetic resin, a ballpoint pen tip, an extruded body of a synthetic resin having an axial ink guide path, and the like. The material constituting the rear end of the nib 2 may be at least a member having a capillary gap in order to enable proper connection with the ink occlusion body 3, for example, resin processing of a fiber bundle. Examples thereof include a porous material such as a body, a heat-bonded processed body of fiber bundles, a felt processed body, and a porous foam of a synthetic resin, or an extruded body of a synthetic resin having an axial ink guide path. In the present invention, the nib 2 includes an ink guide member.

(Partition wall)
The partition wall 51 partitions the ink storage body 3 and the ink tank 7, and actually partitions the ink tank 7 and the storage body storage portion that stores the ink storage body 3. The rear surface of the partition wall 51 faces the ink tank 7.

(Ink tank)
For example, the ink tank 7 may be formed directly on the writing instrument body (that is, the ink tank 7 forms a part of the writing instrument body) or may be housed in the writing instrument body. In the present invention, the ink 8 stored in the ink tank 7 specifically includes writing instrument ink (for example, water-based ink, oil-based ink) or coating liquid (for example, cosmetic liquid, correction liquid, adhesive, Paint, liquid medicine, etc.).

The present invention can sufficiently prevent ink leakage and ink blowing from the pen tip side even when the pressure in the ink tank changes abruptly.

A direct liquid writing instrument 1 according to an embodiment of the present invention is shown in FIGS.
The direct liquid writing instrument 1 according to the present embodiment includes a pen tip 2, an ink occlusion body 3 connected to the rear end of the pen nib 2, a partition member 5 disposed behind the ink occlusion body 3, and the An ink tank 7 provided behind the partition member 5, a shaft cylinder 4 that holds the pen tip 2 at the front end and accommodates the ink occlusion body 3, the partition member 5, and the ink tank 7 inside, It comprises a tail plug 6 detachably screwed into the rear end opening of the shaft tube 4 and a cap 11 detachably provided on the pen tip 2 side.

Pen nib The nib 2 is a rod-like body obtained by resin processing of synthetic resin fibers (for example, polyester fibers, acrylic fibers, nylon fibers, etc.). The front end of the nib 2 is ground like a bullet. The outer peripheral surface of the rear end portion of the nib 2 is chamfered in a tapered shape.

Ink occlusion body The ink occlusion body 3 is made of a processed body of cylindrical synthetic resin fibers (for example, polyester fibers). The outer peripheral surface of the ink occlusion body 3 is covered with a cylindrical outer skin. The outer skin is made of a synthetic resin film (for example, a polyethylene terephthalate film). The rear end of the pen tip 2 is inserted into the axial center of the front end surface of the ink storage member 3 and the rear end of the pen tip 2 is positioned inside the ink storage member 3.

-Shaft cylinder The said shaft cylinder 4 is a cylindrical body obtained by injection molding of synthetic resins (for example, polypropylene, polyethylene, etc.). The shaft cylinder 4 has a tip 41 that holds the outer peripheral surface of the nib 2, and a main body 42 that is connected to the rear of the tip 41 and accommodates the ink occlusion body 3, the partition member 5, and the ink tank 7. It consists of.

A plurality of ribs 43 extending in the front-rear direction are integrally formed on the inner surface of the shaft cylinder 4 (that is, from the inner surface of the tapered portion 41 to the front inner surface of the main body portion 42). In the rib 43, a step-shaped regulating wall 43 a is formed in the vicinity of the connecting portion between the tip 41 of the shaft cylinder 4 and the main body 42. The front end surface of the ink occlusion body 3 is in axial contact with the restriction wall portion 43a, and the outer circumferential surface of the ink occlusion body 3 is pressed and held by the rib 43 on the inner surface of the front portion of the main body portion. The outer peripheral surface of the nib 2 is pressed and held by the rib 43 on the inner surface of the tip 41. A cylindrical wall portion 43b is integrally formed between a portion of the rib 43 that holds the outer peripheral surface of the nib 2 and a portion that holds the outer peripheral surface of the ink occlusion body 3.

By the ribs 43, between the outer peripheral surface of the ink storage body 3 and the inner surface of the main body 42, between the front end surface of the ink storage body 3 and the inner surface of the shaft cylinder 4, and between the outer peripheral surface of the pen tip 2 and the inner surface of the tip 41. In between, the air passage 10 is formed. The front side of the air passage 10 is opened to the outside from the front end of the shaft cylinder 4, and the rear side of the air passage 10 is in communication with the rear end surface of the ink occlusion body 3. That is, the air passage 10 communicates the front end surface of the ink storage body 3 and the rear end surface of the ink storage body 3 with the outside air.

Partition member The partition member 5 is obtained by injection molding of a synthetic resin (for example, polypropylene, polyethylene, etc.). The partition member 5 includes a partition wall 51 that partitions the ink storage body 3 and the ink tank 7, and a plurality of partitions (specifically, protruding forward from the front surface of the partition wall 51 and pierced and connected to the inside of the ink storage body 3. 2) connecting pipes 52, a connecting portion 53 formed at the rear portion of the partition wall 51 and inserted into the inner surface of the front end opening of the ink tank 7, and protruding in the axial direction from the front surface or the rear surface of the partition wall 51. And an attachment tube portion 54 fixed to the inner surface of the shaft tube 4 (the inner surface of the main body portion 42). The ink occlusion body 3 is accommodated in a space (that is, an occlusion body accommodation portion) formed by the shaft cylinder 4 and the partition wall 51. A projecting piece 53a for pressing one side of the plug 71 that closes the front end opening of the ink tank 7 is integrally formed at the rear end of the connecting portion 53.

In the present embodiment, the rear surface of the partition wall 51 inside the connection portion 53 is located behind the front end of the ink tank 7. Further, the rear surface of the partition wall 51 inside the connection portion 53 is positioned in front of the rear end of the protruding piece 53a.

In the present embodiment, the mounting cylinder portion 54 surrounds the outer periphery of the base portion of each communication pipe 52 in front of the partition wall 51, but may be configured to surround the outer periphery of the connection portion 53 behind the partition wall 51. The partition wall 51 and the connection portion 53 have a circular cross section, and the communication pipe 52 and the attachment tube portion 54 are cylindrical. The projecting piece 53a has a circular cross-sectional shape.

The partition wall 51, the respective communication pipes 52, the connection portion 53, and the mounting cylinder portion 54 are integrally connected. That is, the partition wall member 5, the communication pipe 52, the connection part 53, and the attachment cylinder part 54 can be comprised by one component by the partition member 5. FIG. In addition to this, the partition wall 51 and other portions (that is, each communication pipe 52, connection portion 53, or attachment tube portion 54) may be configured by assembling separate parts.

Abutting wall portion As shown in FIG. 3 (1), an abutting wall portion 51 a made of a plate-like rib is integrally formed on the front surface of the partition wall 51. The abutting wall portion 51 a abuts on the rear end surface of the ink occlusion body 3. A gap 9 communicating with the outside air is formed between the partition wall 51 and the rear end surface of the ink occluding body 3 by the contact wall portion 51a. The gap 9 is communicated with the outside air through the air passage 10. A part of the abutting wall portion 51a is formed between a base portion and a base portion of each communication pipe 52, and a base side wall of each communication pipe 52 is connected. Thereby, the bending strength of each communication pipe 52 is improved, and bending of each communication pipe 52 with respect to the partition wall 51 can be suppressed. The abutting wall portion 51a has a transverse cross section that is branched, radial, or cross-shaped.

-Communication pipe The flow path 52a is provided in the inside of each of the communication pipes 52 in the axial direction, and the flow path 52a is opened at both ends (that is, only both ends) of the communication pipe 52. The front ends of the communication pipes 52 are opened inside the ink storage body 3. The rear end of each of the communication pipes 52 is opened in the ink tank 7 behind the ink storage body 3. Each flow passage 52 a of the communication pipe 52 communicates with the ink storage body 3 only at the front end of each of the communication pipes 52, and does not communicate with the ink storage body 3 at other portions of the communication pipe 52.

Since each of the communication pipes 52 is arranged in parallel between the ink storage body 3 and the ink tank 7, a plurality of independent circulations are provided between the ink storage body 3 and the ink tank 7 behind the ink storage body 3. A path 52a is provided in parallel. Each flow passage 52 a of the communication pipe 52 is penetrated to a location away from the axis of the partition wall 51 located inside the connection portion 53.

The front end of each of the communication pipes 52 is inserted by being stabbed forward from the rear end of the ink storage body 3, and finally located near the rear end of the pen tip 2 inside the ink storage body 3. When the front ends of the communication pipes 52 are inserted into the ink storage body 3, the front ends of the communication pipes 52 press and compress the fibers of the ink storage body 3 forward. Accordingly, the fiber density of the ink storage body 3 in the vicinity of the front end of each communication pipe 52 is set to be higher than the fiber density of the ink storage body 3 in a portion other than the vicinity of each front end of the communication pipe 52. That is, a high-density portion 31 having a high fiber density (a high-density portion 31 having a high capillary force) and a low-density portion 32 having a low fiber density (a low-density portion 32 having a low capillary force) are formed inside the ink occlusion body 3. The The high density portion 31 is formed inside the ink occlusion body 3, and the low density portion 32 is formed behind the high density portion 31. The high density portion 31 and the low density portion 32 are connected. Each of the communication pipes 52 penetrates the low density portion 32 from the rear to the front, and the front end of each of the communication pipes 52 is positioned inside the high density portion 31 ahead of the low density portion 32. In the present embodiment, the porosity (porosity) of the low density portion 32 is set to 85% to 93%, and the porosity of the low density portion 32 and the porosity of the high density portion 31 are The difference is set to 20%.

The front end of each of the communication pipes 52 is disposed at a position spaced radially outward from the axis of the ink storage body 3. Specifically, the front ends of the communication pipes 52 are arranged at equal intervals on the same circumference centered on the axis of the ink storage body 3. In the present embodiment, since there are two communication pipes 52, the communication pipes 52 are arranged at 180 ° symmetrical positions with respect to the axis of the ink occlusion body 3. Since the nib 2 is located at the axial center of the ink occlusion body 3, the front end of each of the communication pipes 52 is not directly connected to the rear end of the nib 2 and is not in contact with the nib 2. It is connected through the inside of the ink occlusion body 3 (high density portion 31) so that ink can be distributed. Further, the front end of each of the communication pipes 52 is located slightly behind the rear end of the pen tip 2. Further, the front ends of the communication pipes 52 coincide with each other in the axial direction.

-Restriction part On the inner surface of the flow passage 52a of each communication pipe 52, a restriction part 55 for reducing the cross-sectional area of each flow passage 52a is formed. The throttle portion 55 is provided at the front end of each communication pipe 52. The throttle portion 55 is formed by an annular inward protruding portion. The throttle portion 55 is integrally formed at the front end of the communication pipe 52, but may be formed by attaching another part. Cross-sectional area of the throttle portion 55 ^is set to 0.5 mm 2 to 4 mm ^2. The cross-sectional area of the flow passage 52a other than the throttle portion 55 (that is, the ink flow passage 52a behind the throttle portion 55) is set larger than the cross-sectional area of the throttle portion 55. The cross section of the inner surface of the throttle portion 55 is circular. The cross-sectional area of the throttle portion 55 is obtained from the inner diameter of the throttle portion 55 (that is, πr ² when the radius r of the inner diameter of the throttle portion 55 is used).

Ink tank The ink tank 7 is a bottomed cylindrical body having a front end opened and a rear end closed, and is obtained by injection molding or blow molding of a synthetic resin. Ink 8 is stored directly in the ink tank 7. The ink 8 stored in the ink tank 7 may be either water-based ink or oil-based ink.

The outer surface of the connecting portion 53 of the partition wall member 5 is detachably fitted to the inner surface of the front end opening of the ink tank 7. When ink 8 in the ink tank 7 is consumed and writing becomes impossible, the ink tank 7 is removed from the connection portion 53, and the connection portion 53 is connected to the front end opening of a new ink tank 7 filled with the ink 8. Insert it. Thereby, writing becomes possible again. A front end opening of the new ink tank 7 is closed by a plug 71. Specifically, a plug 71 is fitted on the inner surface of the front end opening of the ink tank 7. When the connection portion 53 is inserted into the front end opening of the ink tank 7, the protruding piece 53 a of the connection portion 53 presses one side of the plug body 71 backward, thereby removing the plug body 71. The front end opening is opened.

In the present embodiment, the volume V2 of the ink occlusion body 3 is set to 55% to 70% of the volume V1 of the space formed by the ink tank 7 and the respective communication pipes 52. In the present embodiment, the volume V3 of the ink occlusion body 3 in front of the front end of the communication pipe 52 positioned in the foremost position among the plurality of communication pipes 52 is the ink tank 7 and each of the communication pipes 52. Is set to 20% to 35% of the volume V1 of the space. In the present embodiment, the volume V4 of the ink occlusion body 3 behind the front end of the communication pipe 52 positioned rearmost among the plurality of communication pipes 52 is the ink tank 7 and each of the communication pipes 52. Is set to 20% to 35% of the volume V1 of the space. In the present embodiment, since the axial positions of the front ends of the communication pipes 52 coincide with each other, the combined volume of the volume V3 and the volume V4 coincides with the volume V2. (See Figure 4)

The ink occlusion body 3 in front of the front end of the communication pipe 52 located in the foremost position among the plurality of communication pipes 52 constituting the volume V3 has a higher density than the ink occlusion body 3 constituting the volume V4. Many parts 31 are included. The ink occlusion body 3 behind the front end of the communication pipe 52 located at the rearmost among the plurality of communication pipes 52 constituting the volume V4 is lower than the ink occlusion body 3 constituting the volume V3. Many density portions 32 are included.

Cap The cap 11 is detachably provided on the pen tip 2 side. By attaching the cap 11 to the pen tip 2 side, the pen tip 2 and the front end opening of the air passage 10 are sealed, and communication between the ink tank 7 and the outside air is blocked.

In the direct liquid writing instrument 1 according to the present embodiment, when the pressure in the ink tank 7 suddenly changes, even if the ink 8 in the ink tank 7 is pushed out through the communication pipe 52, the ink 8 is stored in the ink. The body 3 is properly impregnated. Thereby, it is possible to sufficiently prevent the ink from leaking out or blowing out from the pen tip 2 side.

It is a longitudinal cross-sectional view which shows the pen tip downward state of embodiment of this invention. (1) is the AA line expanded sectional view of FIG. 1, (2) is the BB line expanded sectional view of FIG. 1, (3) is the CC line expanded sectional view of FIG. (1) is the DD sectional view enlarged from FIG. 1, (2) is the EE sectional enlarged view of FIG. It is a mimetic diagram showing volume V1, volume V2, volume V3, and volume V4 in an embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Direct liquid type writing instrument 2 Pen tip 3 Ink occlusion body 31 High density part 32 Low density part 4 Shaft cylinder 41 Tip detail 42 Main body part 43 Rib 43a Restriction wall part 43b Tubular wall part 5 Partition member 51 Partition wall 51a Contact wall part 52 Communication pipe 52a Flow path 53 Connection part 53a Projection piece 54 Mounting cylinder part 55 Throttle part 6 Tail plug 7 Ink tank 71 Plug body 8 Ink 9 Crevice 10 Air path 11 Cap

Claims (6)

A pen tip, an ink occlusion body connected to the rear end of the pen nib, an ink tank that is disposed behind the ink occlusion body and directly stores ink, and between the ink tank and the ink occlusion body Each of the communication pipes is provided with a flow passage, each of the flow passages opens at the front end and the rear end of each communication pipe, and the front end of each of the communication pipes A direct liquid type writing instrument located inside the ink occlusion body, provided on the inner surface of the flow passage of each communication pipe is provided with a throttle portion for reducing the cross-sectional area of the flow passage, the cross-sectional area of the throttle portion is A direct liquid-type writing instrument characterized in that it is set smaller than the cross-sectional area of the flow passage other than the throttle part. 2. The direct liquid writing instrument according to claim 1, wherein the throttle portion is provided at a front end of each of the communication pipes, and each of the flow passages communicates with the ink occlusion body only at the front end opening of each of the communication pipes. Ink type writing instrument according to claim 1 or 2, wherein the cross section of the narrowing portion is in the range of 0.15 mm ² to 5 mm ^2. The direct liquid writing instrument according to any one of claims 1 to 3, wherein the volume V2 of the ink occlusion body is set to 40% or more of the volume V1 of the space formed by the ink tank and each of the communication pipes. The volume V3 of the ink storage body in front of the front end of the communication pipe positioned in the foremost position among the plurality of communication pipes is set to 10% or more of the volume V1 of the space formed by the ink tank and each of the communication pipes. The direct liquid type writing instrument according to any one of claims 1 to 4. The volume V4 of the ink occlusion body behind the front end of the communication pipe located rearmost among the plurality of communication pipes is set to 10% or more of the volume V1 of the space formed by the ink tank and each of the communication pipes. The direct liquid type writing instrument according to any one of claims 1 to 5.

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