JP2005199695A - Double-headed writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-headed writing utensil having an ink tank with a highly charming appearance and, additionally, enabling the discrimination of two ink colors when it is housed in a pen stand. <P>SOLUTION: A partition wall 3 is integrally formed with a transparent or semitransparent barrel 2 inside the barrel. A first ink tank 5A is opened outside through one end of the barrel 2, and a second ink tank 5B is opened outside through the other end of the barrel 2. At the opening part of the first ink tank 5A, a first ink reserving member 6A is provided. At the back of the first ink reserving member 6A, a first ink storing part 7A is provided. At the opening part of the second ink tank 5B, a second ink reserving member 6B is provided. At the back of the second ink reserving member 6B, a second ink storing part 7B is provided. The first ink storing part 7A and the second ink storing part 7B are provided through the partition wall 3 so as to radially overlap with each other. The first storing part 7A and the second storing part 7B store ink 8A and ink 8B having colors different from each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a direct liquid type double-headed writing instrument having pen tips at both ends of a shaft cylinder. In the present invention, “front” refers to the first nib side in the first ink tank, refers to the second nib side in the second ink tank, and “rear” refers to the first nib side. In the ink tank, the first ink storage portion side is indicated, and in the second ink tank, the second ink storage portion side is indicated.

  Conventionally, regarding this type of double-headed writing instrument, for example, Patent Document 1 discloses a writing instrument in which a nib unit having a direct liquid structure in which a nib, a nib holder, and an ink tank are fixed is detachably attached to both ends of the cylinder shaft. Has been. Further, in Patent Document 1, the pen tip, the cover seat, the clip, and the color-specific band are colored in the same color as the ink to be put in the ink tank, and the ink tank, the nib cover, and the cap are made of a transparent synthetic resin formed product. It is disclosed to form.

JP 2002-36786 A

  In the writing instrument of Patent Document 1, the respective inks in the two ink storage portions are visually recognized separately in front and rear. In particular, in the writing instrument of Patent Document 1, when there is a large amount of air in the ink storage section, when either one of the pen tips faces downward, the distance before and after each of the inks increases, and the appearance is not interesting. To do. In addition, when the writing instrument of Patent Document 1 is in an accommodation display state, such as the writing stand, the ink color of the upper pen tip protruding outside the writing stand etc. can be visually recognized, but it is accommodated inside the writing stand. The ink color of the lower pen tip is not visible, which may inconvenience the user.

  The writing instrument of Patent Document 1 has a structure in which another member (color display member) such as a clip or a color band colored in the same color as the ink is attached to the cap in order to identify the ink from the outside. Therefore, the number of parts increases and the manufacturing cost increases. Moreover, since the writing instrument of Patent Document 1 is configured so that each cap displays an ink color, the cap must be mounted only on the same nib side as the ink color, If the cap is mistakenly attached to the pen tip side opposite to the ink color, there is a risk that the user may be confused in identifying the ink color.

  The present invention solves the above-mentioned problems, and the appearance of the ink tank is increased and the two ink colors can be discriminated even when stored in a brush or the like. It is an object of the present invention to provide a double-headed writing instrument that can simplify the structure for identification and can easily identify the ink color regardless of the pen tip side.

[1] In the present invention, both ends of the shaft tube 2 made of a transparent or translucent material are opened, and the partition wall 3 is integrally formed in the shaft tube 2 so that the shaft tube 2 is externally connected to one end. A first ink tank 5A that opens to the outside and a second ink tank 5B that opens to the outside from the other end of the shaft cylinder 2, and the first ink tank 5A and the second ink tank 5B communicate with each other. The first ink reservoir member 6A connected to the first pen tip 4A is provided in the opening of the first ink tank 5A, and the first ink reservoir member 6A behind the first ink reservoir member 6A is provided. A first ink reservoir 7A is provided in one ink tank 5A, and the first ink reservoir 6A temporarily holds overflow ink in response to a pressure increase in the first ink reservoir 7A. In the opening of the second ink tank 5B, A second ink reservoir member 6B connected to the second nib 4B, and a second ink reservoir 7B in the second ink tank 5B behind the second ink reservoir member 6B. The second ink reservoir member 6B temporarily holds the overflow ink corresponding to the pressure increase in the second ink reservoir 7B, and the first ink reservoir 7A and the second ink reservoir 7B. An ink reservoir 7B is provided so as to overlap in the radial direction via the partition wall 3, and inks 8A and 8B of different colors are stored in the first ink reservoir 7A and the second ink reservoir 7B. A double-headed writing instrument 1 (Claim 1) is a requirement.

  In the double-headed writing instrument 1 according to the first aspect, the first ink reservoir 7A and the second ink reservoir 7B are provided so as to overlap in the radial direction via the partition wall 3, and the first ink reservoir 7A With the configuration in which different colors of ink are stored in the second ink reservoir 7B, the two colors of ink in the ink reservoir can be visually observed in close proximity, and the appearance is more interesting. In addition, the double-headed writing instrument 1 according to claim 1 includes a first ink reservoir 7A and a second ink reservoir 7B that are exposed from above the brush holder even when the writing instrument is in a storage display state. Can be visually recognized at the same time, and the combination of two colors (that is, how many colors and what combination of two inks) can be easily recognized. The combination of the different color inks includes a case where both are different color inks and a case where one is a color ink and the other is a colorless ink (colorless liquid).

[2] In the double-headed writing instrument 1 of the first aspect, the shaft cylinder 2 on the first nib 4A side is provided with a detachable first cap 9A and the shaft cylinder 2 on the second nib 4B side. The first cap 9A and the second cap 9B are made of a transparent or semi-transparent material, and the first nib 4A is the first ink reservoir 7A. The second nib 4B is colored in the same color as the ink in the second ink reservoir 7B, and the first cap 9A and the second cap 9B are colored in the shaft cylinder 2. It is preferable that the first pen tip 4A and the second pen tip 4B are configured to be visible from the outside when mounted on both ends (Claim 2).

  The double-headed writing instrument 1 according to claim 2 does not need to provide a color display member on the first cap 9A and the second cap 9B. Therefore, the structure is simplified, the manufacturing cost can be suppressed, and it can be provided at low cost. . Further, in the case where the first ink reservoir and the second ink reservoir are overlapped in the radial direction via the partition wall 3, it is difficult to identify the ink color of the pen tip only by looking at the ink reservoir. However, since the first cap 9A and the second cap 9B according to claim 2 are made of a transparent or translucent material, the first cap 9A and the second cap 9B are attached to the first cap 9A and the second cap 9B. The ink colors of the nib 4A and the second nib 4B can be easily visually recognized. In addition, coloring the pen tip in the same color as the ink means, for example, a configuration in which the pen tip is impregnated with ink or the pen tip is impregnated with ink or attached to the outer surface of the pen tip to make it visible from the outside. Examples include a configuration in which the outer surface is colored in substantially the same color as the ink, or a configuration in which the pen tip holder that holds the outer surface of the pen tip is colored in the same color as the ink.

[3] In the double-headed writing instrument 1 according to claim 2, the first cap 9A can be mounted on either the first nib 4A side or the second nib 4B side, and the first It is preferable that the second cap 9B can be mounted on either the first nib 4A side or the second nib 4B side (Claim 3).

  In the double-headed writing instrument 1 according to claim 3, the first cap 9A and the second cap 9B can be mounted on either the first nib 4A side or the second nib 4B side. Configuration (specifically, the shape of the fitting portion of the first cap 9A and the shape of the fitting portion of the second cap 9B are the same, and the shape of the fitting portion of the first ink tank 5A) And the shape of the fitting portion of the second ink tank 5B are the same), the ink color identification is confused regardless of which pen tip side the first cap 9A and the second cap 9B are mounted on. This makes it easy to identify the ink color and eliminates the need for the user to distinguish the first cap 9A and the second cap 9B from each other and attach them to each pen tip.

[4] In the double-headed writing instrument 1 according to the first, second, or third aspect, when the first pen tip 4A or the second pen tip 4B is turned downward, the ink 8A in the first ink reservoir 7A and the second It is preferable that the ink 8B in the second ink reservoir 7B is visible to the left and right (claim 4).

  When the first nib 4A or the second nib 4B is faced downward (that is, when one of the first nib 4A or the second nib 4B is faced down and the other is faced up), two colors up and down The double-headed writing instrument 1 of claim 4 is filled with a sufficient amount of ink and the first nib 4A or the second nib 4B faces downward. The two color inks can be visually recognized from the left and right (that is, in the radial direction) through the partition wall 3, and the visual recognition in the state where the two color inks are overlapped in the radial direction is further ensured. As a result, the user can purchase the first ink reservoir 7A and the second ink reservoir 7B at the same time, even in the case where the user is buying and displaying the brush, etc. Furthermore, the combination of two colors can be easily recognized.

  The double-headed writing instrument according to claim 1 allows the two colors of ink in the ink reservoir to be viewed close to each other, the appearance is more interesting, and the first ink reservoir even in the storage display state of the brush stand or the like And the second ink reservoir can be viewed at the same time, and the combination of the two colors can be easily viewed.

  In addition to the effect of the first aspect, the double-headed writing instrument according to the second aspect can simplify the structure for identifying the ink color, reduce the manufacturing cost, and can reduce the manufacturing cost. The color can be easily recognized.

  In addition to the effect of claim 2, the double-headed writing instrument of claim 3 can easily identify the ink color regardless of whether the first cap and the second cap are attached to the pen tip side. There is no need for the user to distinguish between the first cap and the second cap and attach them to each pen tip.

  The double-headed writing instrument according to the fourth aspect of the present invention can maintain the appearance of interest even in the case where the writing stand is in an accommodation display state, and can more easily visually recognize the combination of two colors.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(First embodiment)
1 to 5 show a first embodiment of the present invention.
The double-headed writing instrument 1 of the present embodiment is mainly mounted on the shaft cylinder 2 provided with the first pen tip 4A and the second pen tip 4B at both ends, and the first pen tip 4A side of the shaft cylinder 2. It consists of a first cap 9A that can be mounted, and a second cap 9B that can be mounted on the second pen tip 4B side of the shaft tube 2.

Shaft cylinder The shaft cylinder 2 is a cylindrical body having both ends opened, and is obtained by injection molding of a transparent or translucent synthetic resin (that is, a colorless transparent or non-colored transparent synthetic resin). A partition wall 3 is formed on the inner surface of the shaft tube 2. By the partition wall 3, a first ink tank 5 </ b> A opening from one end of the shaft tube 2 and a second ink tank 5 </ b> B opening from the other end of the shaft tube 2 are formed inside the shaft tube 2. The partition wall 3 prevents the first ink tank 5A and the second ink tank 5B from communicating with each other and prevents ink from flowing through each other. Examples of the transparent or translucent synthetic resin include polypropylene.

Partition Wall The partition wall 3 has a configuration extending in the axial direction (that is, a configuration extending at least parallel to the axis or a configuration inclined with respect to the axis). That is, one end of the partition wall 3 is connected to the inner surface of the side wall of the shaft cylinder 2 near the first ink storage member 6A, and the other end of the partition wall 3 is the side wall of the shaft cylinder 2 near the second ink storage member 6B. Connected to the inner surface. In the present embodiment, the partition wall 3 includes a central wall portion 31 that extends substantially parallel to the axis, and an inclined wall portion 32 and an inclined wall portion 33 that are inclined with respect to the axis extending from both ends of the central wall portion 31. It consists of. The inclined wall portion 32 is integrally connected to the inner surface of the shaft cylinder 2 side wall in the vicinity of the first ink reservoir member 6A, and the inclined wall portion 33 is connected to the inner surface of the shaft cylinder 2 in the vicinity of the second ink reservoir member 6B. Are integrally connected to each other. By the partition wall 3, the first ink storage part 7 </ b> A and the second ink storage part 7 </ b> B are provided in a two-layer overlapping state in the radial direction with the partition wall 3 interposed therebetween.

Ink tank The first ink tank 5A includes a large-diameter portion 51A having a circular cross section that opens forward, and a small-diameter portion 52A having a semicircular cross-section that is connected to the rear of the large-diameter portion 51A. Become. A first ink reservoir member 6A is fitted into the large diameter portion 51A of the first ink tank 5A. In the first ink tank 5A behind the first ink reservoir member 6A (that is, the space formed by the large-diameter portion 51A and the small-diameter portion 52A behind the first ink reservoir member 6A), The ink reservoir 7A is formed.

  Similarly, the second ink tank 5B is also composed of a large-diameter portion 51B having a circular cross section that opens forward and a small-diameter portion 52B having a semicircular cross-section that is continuously provided behind the large diameter portion 51B. Become. The second ink reservoir member 6B is fitted into the large diameter portion 51B of the second ink tank 5B. In the second ink tank 5B behind the second ink reservoir member 6B (that is, the space formed by the large diameter portion 51B and the small diameter portion 52B behind the second ink reservoir member 6B), the second The ink reservoir 7B is formed.

  The small-diameter portion 52A of the first ink tank 5A and the small-diameter portion 52B of the second ink tank 5B are in a two-layer superposition state that overlaps in the radial direction via the partition wall 3. The outer diameter of the overlapping portion of the small diameter portion 52A of the first ink tank 5A and the small diameter portion 52B of the second ink tank 5B is equal to the outer diameter of the large diameter portion 51A of the first ink tank 5A and the second diameter. The outer diameter is set to be substantially the same as that of the large diameter portion 51B of the ink tank 5B.

Ink reservoir member The first ink reservoir member 6A is a member that temporarily holds overflow ink in response to a pressure increase in the first ink reservoir 7A. In the present embodiment, a plurality of ink reservoir members are provided. It is an injection-molded body of a synthetic resin (for example, ABS resin) provided with disk-like comb teeth. A first nib 4A is attached to the front end of the first ink reservoir member 6A. A shaft hole is formed through the shaft center of the first ink reservoir member 6A, and an ink guide core 61A is inserted into the shaft hole. The front end of the ink guide core 61A is connected to the first nib 4A, and the rear end of the ink guide core 61A is connected to the first ink reservoir 7A. The ink guide core 61A may be any of a fiber processed body, a porous body, and a synthetic resin extruded body having an axial capillary passage, but in the present embodiment, a fiber resin processed body (for example, Polyester fiber resin processed body) is employed.

  Similarly, the second ink reservoir member 6B is also a member that temporarily holds overflow ink in response to a pressure increase in the second ink reservoir 7B. In the present embodiment, a plurality of discs are used. It is an injection-molded body of a synthetic resin (for example, ABS resin) having a comb-like tooth. A second pen tip 4B is attached to the front end of the second ink reservoir member 6B. A shaft hole is formed through the shaft center of the second ink reservoir member 6B, and an ink guide core 61B is inserted into the shaft hole. The front end of the ink guide core 61B is connected to the second nib 4B, and the rear end of the ink guide core 61B is connected to the second ink reservoir 7B. The ink guide core 61B may be any of a fiber processed body, a porous body, and a synthetic resin extruded body having an axial capillary passage. In the present embodiment, a fiber resin processed body (for example, Polyester fiber resin processed body) is employed.

  The first ink reservoir member 6A is colored in substantially the same color as the first ink 8A in the first ink reservoir 7A. That is, the first ink reservoir member 6A is formed of a synthetic resin material having substantially the same color as the first ink 8A in the first ink reservoir 7A. The second ink reservoir member 6B is colored in substantially the same color as the second ink 8B in the second ink reservoir 7B. That is, the second ink reservoir member 6B is formed of a synthetic resin material having substantially the same color as the second ink 8B in the second ink reservoir 7B. Since the shaft cylinder 2 is made of a transparent or translucent material, the colored ink colors of the first ink storage member 6A and the second ink storage member 6B can be visually recognized from the outside of the shaft cylinder 2.

Ink The first ink 8A is stored in the first ink reservoir 7A, and the second ink 8B is stored in the second ink reservoir 7B. A combination of the first ink 8A and the second ink 8B having different colors is employed. The first ink 8A in the first ink reservoir 7A and the second ink 8B in the second ink reservoir 7B are visible from the outside because the shaft cylinder 2 is made of a transparent or translucent material. Is possible. In the present embodiment, the first ink 8A and the second ink 8B are inks containing fluorescent pigments or fluorescent dyes. Thereby, the good-looking double-headed writing instrument 1 with excellent coloring is obtained. The combination of the colors of the first ink 8A and the second ink 8B is, for example, a combination of fluorescent yellow and fluorescent pink, a combination of fluorescent yellow and fluorescent orange, a combination of fluorescent yellow and fluorescent green, or fluorescent pink and fluorescent orange. A combination, a combination of fluorescent pink and fluorescent green, a combination of fluorescent yellow and fluorescent blue, a combination of fluorescent yellow and fluorescent violet, or the like is preferable from the viewpoint of good color appearance.

  The first ink 8A and the second ink 8B are visually recognized through the partition wall 3 in a two-layered state in the radial direction. The first ink reservoir 7A and the second ink reservoir 7B have a small diameter of the first ink tank 5A regardless of which of the first nib 4A or the second nib 4B is directed downward. The filling amounts of the first ink 8A and the second ink 8B are set so that the ink is always present in the portion 52A and the small diameter portion 52B of the second ink tank 5B. Accordingly, when the first nib 4A or the second nib 4B is turned downward, the first ink 8A and the second ink 8B are separated into two layers on the left and right (that is, in the radial direction) via the partition wall 3. It becomes possible to visually recognize in a multilayered state.

  In addition, the axial length of the partition wall 3 constituting the multi-layered portion is that the two colors are easily visible, and the rear end of the first ink reservoir member 6A and the second ink reservoir member 6B are It is preferable to set at least 20% or more (preferably 50% or more, more preferably 70% or more) of the length in the axial direction between the rear end. In addition, the axial length of the layered portion of the first ink 8A and the second ink 8B with either one of the pen nibs facing downward is also easy to see the two colors. Filling with the first ink 8A and the second ink 8B so as to be set to at least 20% or more of the axial length between the rear end of the reservoir member 6A and the rear end of the second ink reservoir member 6B. It is preferable to set the amount.

Pen nib The first nib 4A is made of a fiber processed body, a brush body, or a porous body, and impregnated with the first ink 8A in the first ink reservoir 7A. The color of the first ink 8A is visually recognized, and the first nib 4A is colored with the color of the first ink 8A. Similarly, the second nib 4B is also a fiber processed body, a brush body, or a porous body, and is impregnated with the second ink 8B in the second ink reservoir 7B, so that the second pen tip 4B is externally impregnated. The color of the second ink 8B is visually recognized, and the second nib 4B is colored to the color of the second ink 8B. In the present embodiment, the first nib 4A and the second nib 4B are made of a fiber resin processed body (for example, a polyester fiber resin processed body) having the same shape.

  In addition to the above, the first pen tip 4A and the second pen tip 4B are, for example, a combination of fiber processed bodies having different shapes, a combination of ballpoint pen tips, a combination of brush brushes, A combination of porous bodies, a combination of fountain pen nibs made of metal plates, both of which have slits at the tips, a combination of pen bodies (plastic pen bodies) made of synthetic resin extrusions, one of which is a fiber processed body The other is a porous body combination, one is a fiber processed body and the other is a plastic pen body combination, one is a fiber processed body and the other is a brush body combination, one is a fiber processed body and the other is a fountain pen tip combination , One is a fiber processed body and the other is a combination of ballpoint pen tips, one is a porous body and the other is a combination of plastic pens, one is a porous body and the other is a combination of brushstrokes, one is porous and the other is a fountain pen Condition Combination of tip, one is porous and the other is a ballpoint pen tip, one is a plastic pen and the other is a brush combination, one is a plastic pen and the other is a fountain pen tip, one is a plastic pen Body and the other is a combination of a ballpoint pen tip, one is a brush brush and the other is a combination of a fountain pen tip, one is a brush brush and the other is a ballpoint tip combination, or one is a combination of a fountain pen tip and the other is a ballpoint pen tip Etc. In the case of the ballpoint pen tip, it is preferable that the outer surface is colored in the same color as the ink in the first ink reservoir 7A and the second ink reservoir 7B. The pen tip of the present invention includes a pen tip holder interposed between the pen tip and the shaft tube 2.

・ Cap mounting structure (see Figs. 4 and 5)
As shown in FIG. 4, the front end portion of the large-diameter portion 51A of the first ink tank 5A has an outward projection 511A formed on its outer peripheral surface, and an annular airtight portion 512A formed on its inner peripheral surface. . Similarly, as shown in FIG. 5, the front end portion of the large-diameter portion 51B of the second ink tank 5B has an outward projection 511B formed on its outer peripheral surface, and an annular airtight portion 512B on its inner peripheral surface. It is formed.

  The first cap 9A is a bottomed cylindrical body having one end closed and the other end opened, and is formed by injection molding of a transparent or translucent synthetic resin (that is, a colorless transparent or non-colored transparent synthetic resin). can get. On the inner surface of the first cap 9A, an outward protrusion 511A of the first ink tank 5A and an inward protrusion 91A capable of getting over and engaging with the outward protrusion 511B of the second ink tank 5B, and a first ink tank An annular airtight portion 512A of 5A and an annular airtight portion 512B of the second ink tank 5B and an annular seal portion 92A that can come into close contact with each other are integrally formed. Examples of the transparent or translucent synthetic resin include polypropylene.

  Similarly, the second cap 9B is also a bottomed cylindrical body with one end closed and the other end opened, and injection of a transparent or translucent synthetic resin (that is, a colorless transparent or non-colored transparent synthetic resin). Obtained by molding. On the inner surface of the second cap 9B, there are an outward projection 511A of the first ink tank 5A and an inward projection 91B that can be engaged with the outward projection 511B of the second ink tank 5B, and the first ink tank. An annular airtight portion 512A of 5A and an annular airtight portion 512B of the second ink tank 5B are integrally formed with a second annular seal portion 92B that can be brought into close contact with. Examples of the transparent or translucent synthetic resin include polypropylene.

  That is, the shape of the fitting portion (that is, the inward projection 91A and the annular seal portion 92A) of the first cap 9A is the same as the shape of the fitting portion (that is, the inward projection 91B and the annular seal portion 92B) of the second cap 9B. In addition, the shape of the fitting portion (that is, the outward projection 511A and the annular airtight portion 512A) of the first ink tank 5A and the shape of the fitting portion (that is, the outward projection 511B and the annular airtight portion 512B) of the second ink tank 5B. The shape is the same. Thereby, the first cap 9A can be mounted on either the first ink tank 5A provided with the first nib 4A or the second ink tank 5B provided with the second nib 4B. The second cap 9B can be attached to the first ink tank 5A having the first nib 4A and the second ink tank 5B having the second nib 4B. That is, the first cap 9A can be attached to either the first nib 4A side or the second nib 4B side barrel 2 and the second cap 9B is It can be attached to either the barrel 2 on the pen tip 4A side or the second pen tip 4B side.

  Since the first cap 9A and the second cap 9B according to the present embodiment are independent and have transparency and no ink color display function, the first pen tip 4A and the second pen 9A are used. No matter which pen tip side of the tip 4B is attached, the ink color identification is not confused, the ink color identification becomes easy, and the user separates the first cap 9A and the second cap 9B. Separately, the trouble of attaching each pen tip becomes unnecessary. In the present embodiment, the clip 93A is integrally formed on the outer surface of the first cap 9A, while the clip 93A is not formed on the outer surface of the second cap 9B. The first cap 9A including the clip 93A may be attached to either the first nib 4A or the second nib 4B, and the user can select it.

  In the present embodiment, the partition wall 3 extending in the axial direction (that is, the partition wall including the central wall portion 31 and the two inclined wall portions 32 and 33 on both sides thereof) is used as the first ink storage member 6A. It is arranged at the central position in the axial direction between the rear end and the rear end of the second ink reservoir member 6B. Thereby, the capacity of the first ink reservoir 7A and the capacity of the second ink reservoir 7B are set equal. In addition to this, the present invention has different capacities of the first ink reservoir 7A and the second ink reservoir 7B as in the following second and third embodiments. Also good.

(Second Embodiment)
FIG. 6 shows a second embodiment of the present invention.
This embodiment is different from the first embodiment in the position of the partition 3.
That is, in the present embodiment, the distance L1 between the connection end of the partition wall 3 on the first pen tip 4A side and the rear end of the first ink storage member 6A is equal to the second pen tip 4B side of the partition wall 3. Is set to be larger than the distance L2 between the connection end of the second ink storage member 6B and the rear end of the second ink storage member 6B. Thereby, the capacity of the first ink reservoir 7A is set larger than the capacity of the second ink reservoir 7B.

  In the present embodiment, the first ink reservoir 7A is filled with ink that is used more frequently by the user than the ink in the second ink reservoir 7B (that is, ink with a high consumption rate). Thereby, the user is prevented from exhausting the ink in the other ink reservoir while leaving the ink in one ink reservoir, and a double-headed writing instrument that can be used for a long time is obtained. In the present embodiment, the first ink 8A and the second ink 8B are inks containing fluorescent pigments or fluorescent dyes. Of the inks containing the fluorescent pigment or the fluorescent dye, fluorescent yellow is generally used frequently and is considered to have a high ink consumption rate. Therefore, in the present embodiment, specifically, fluorescent yellow is adopted as the first ink 8A, and any one of fluorescent pink, fluorescent orange, fluorescent green, fluorescent blue, or fluorescent violet is used as the second ink 8B. One is adopted.

  The ratio of the capacity of the first ink reservoir 7A to the capacity of the second ink reservoir 7B (the capacity of the second ink reservoir 7B / the capacity of the first ink reservoir 7A) is 0.3-0. 8 (preferably 0.4 to 0.7) is effective. When the ratio is smaller than 0.3, the length of the partition wall 3 in the axial direction cannot be set sufficiently, and the first ink storage portion 7A and the second ink storage portion 7B are arranged in the radial direction via the partition wall 3. It becomes difficult to sufficiently set the two-layered overlapping state. On the other hand, when the ratio is larger than 0.8, the difference in capacity between the first ink reservoir 7A and the second ink reservoir 7B is almost eliminated. Since the other configuration of the present embodiment is the same as that of the first embodiment, description thereof is omitted.

(Third embodiment)
7 and 8 show a third embodiment of the present invention.
This embodiment also differs from the first embodiment in the positions of the partition walls 3 as in the second embodiment. That is, in the first embodiment, the central wall portion 31 is located at the axial center of the shaft cylinder 2, whereas in the present embodiment, the central wall portion 31 is located at a position that is radially away from the axial center. In addition, the inclined wall portion 33 constituting the bottom wall of the first ink reservoir 7A is set larger than the inclined wall portion 32 constituting the bottom wall of the second ink reservoir 7B. Thereby, the capacity of the first ink reservoir 7A (that is, the capacity of the small diameter part 52A) is set larger than the capacity of the second ink reservoir 7B (that is, the capacity of the small diameter part 52B).

  Similar to the second embodiment, in this embodiment, the ink that is used more frequently by the user than the ink in the second ink reservoir 7B (that is, the consumption speed is faster) is stored in the first ink reservoir 7A. Ink). Thereby, the user is prevented from exhausting the ink in the other ink reservoir while leaving the ink in one ink reservoir, and a double-headed writing instrument that can be used for a long time is obtained. In the present embodiment, the first ink 8A and the second ink 8B are inks containing fluorescent pigments or fluorescent dyes. Of the inks containing the fluorescent pigment or the fluorescent dye, fluorescent yellow is generally used frequently and is considered to have a high ink consumption rate. Therefore, in the present embodiment, specifically, fluorescent yellow is adopted as the first ink 8A, and any one of fluorescent pink, fluorescent orange, fluorescent green, fluorescent blue, or fluorescent violet is used as the second ink 8B. One is adopted.

  The ratio of the capacity of the first ink reservoir 7A to the capacity of the second ink reservoir 7B (the capacity of the second ink reservoir 7B / the capacity of the first ink reservoir 7A) is 0.3-0. 8 (preferably 0.4 to 0.7) is effective. When the ratio is smaller than 0.3, the core pin of the mold for molding the inner surface of the small diameter portion 52B of the second ink tank 5B becomes thin, and it becomes difficult to mold the small diameter portion 52B. On the other hand, when the ratio is larger than 0.8, the difference in capacity between the first ink reservoir 7A and the second ink reservoir 7B is almost eliminated. Since the other configuration of the present embodiment is the same as that of the first embodiment, description thereof is omitted.

It is an external view which shows 1st Embodiment of the double-headed type writing instrument of this invention. It is a longitudinal cross-sectional view of FIG. It is an AA line expanded sectional view of FIG. FIG. 3 is an enlarged vertical sectional view of the first pen tip side in FIG. 2. FIG. 3 is an enlarged vertical sectional view of a second pen tip side in FIG. 2. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the double-headed type writing instrument of this invention. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the double-headed type writing instrument of this invention. FIG. 8 is an enlarged sectional view taken along line B-B in FIG. 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Double-headed writing instrument 2 Shaft cylinder 3 Partition 31 Central wall part 32 Inclined wall part 33 Inclined wall part 4A 1st pen tip 5A 1st ink tank 51A Large diameter part 511A Outward protrusion 512A Annular airtight part 52A Small diameter part 6A 1st Ink storage member 61A Ink guide core 7A First ink storage portion 8A First ink 9A First cap 91A Inward projection 92A Annular seal portion 93A Clip 4B Second nib 5B Second ink tank 51B Large diameter Portion 511B outward projection 512B annular airtight portion 52B small diameter portion 6B second ink reservoir member 61B ink guide core 7B second ink reservoir 8B second ink 9B second cap 91B inward projection 92B annular seal portion L1 Distance L2 between the connection end on the first pen tip side and the rear end of the first ink reservoir member The connection end on the second pen tip side of the partition and the second in The distance between the reservoir member rear end

Claims (4)

A first ink tank that opens to the outside from one end of the shaft cylinder by opening both ends of the shaft cylinder made of a transparent or translucent material and integrally forming a partition inside the shaft cylinder; A second ink tank that opens to the outside from the other end of the cylinder, and the first ink tank and the second ink tank do not communicate with each other;
A first ink reservoir member connected to the first pen tip is provided at the opening of the first ink tank, and the first ink tank is provided in the first ink tank behind the first ink reservoir member. An ink reservoir, and the first ink reservoir member temporarily holds overflow ink in response to a pressure increase in the first ink reservoir,
A second ink reservoir member connected to the second pen tip is provided at the opening of the second ink tank, and a second ink reservoir member is provided in the second ink tank behind the second ink reservoir member. An ink reservoir, and the second ink reservoir member temporarily holds overflow ink in response to a pressure increase in the second ink reservoir,
The first ink reservoir and the second ink reservoir are provided so as to overlap in the radial direction through the partition wall, and the first ink reservoir and the second ink reservoir are of different colors. A double-headed writing instrument that stores ink. The first pen tip side barrel is provided with a detachable first cap, and the second pen tip side barrel is provided with a detachable second cap. The first cap and the second cap The cap is made of a transparent or translucent material, the first nib is colored in the same color as the ink in the first ink reservoir, and the second nib is ink in the second ink reservoir. The same color,
2. The double-headed writing instrument according to claim 1, wherein when the first cap and the second cap are attached to both ends of the shaft cylinder, the first pen tip and the second pen tip are visible from the outside. The first cap can be mounted on either the first pen tip side or the second pen tip side, and the second cap can be attached to the first pen tip side or the second pen tip side. The double-headed writing instrument according to claim 2, which can be mounted on either side. 4. The structure according to claim 1, 2, or 3, wherein the ink in the first ink reservoir and the ink in the second ink reservoir are visible to the left and right when the first nib or the second nib is turned downward. The double-headed writing instrument described.

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