KR840001167B1 - A writing tool - Google Patents

Abstract

The pen using low-viscosity ink includes an ink-containing tube(10), sponge matter(4) which absorbs and contains ink by capillary action, a partitioning cylinder(5) with holes(9) (5b), to route an overflow of ink from the container, the other(9) to route the ink back, a space(6) to hold the overflown ink, a gap(7) between the main body and cylinder(5) which forms the route to exchange air and ink, an air ventilating tube(8) which is located in the center of the space(6) to keep the tube open.

Description

Handwriting

1 is a cross-sectional view of a first embodiment of the present invention before the ink injection state of the writing instrument.

2, 3 and 4 are cross-sectional views taken along lines II-II, III-III and IV-IV of FIG.

5 is an explanatory view showing the structure of the partition container in cross section and a bottom view;

6, 7, 8, and 9 are cross-sectional views corresponding to FIGS. 1, 2, 3, and 4 showing a state in which ink is injected into the writing instrument body.

10, 11, 12, and 13 are cross-sectional views corresponding to FIGS. 1, 2, 3, and 4 showing an exchange state of air and liquid during writing.

14 and 15 are explanatory views of the operation of the case where the internal pressure rise and the internal pressure drop occur in the downward state of the pen.

16 and 17 are explanatory diagrams of the case where the pressure rise and the pressure drop occur in the downward state of the pen.

18, 19, and 20 are explanatory diagrams of the case where the pressure increase and the pressure drop in the horizontal state of the pen occur.

21, 22, 23, 24, and 25 are structural explanatory diagrams showing other embodiments of the partition container and the ink return passage in cross section or in a side view.

Fig. 26 is a sectional view of principal parts showing a modification of the exchange passage between air and liquid.

Fig. 27 shows another embodiment in which the present invention is applied to a writing instrument for a recorder, where A is a center longitudinal sectional view and B is a right side view.

* Explanation of symbols for main parts of the drawings

1,1 ′: Writing instrument body 1a ′: Inner hole

2,2 ′: Cursive portion 2a: Bowl

2b: bowl holder 2c: ink relay wick

3, 12: stopper 4: ink absorption storage body

4a: primary ink absorber 4b: secondary ink absorber

5,5 ′: divider

5a, 15a: Circumferential nodal plane formed on the side of the divider

5b, 15b: Notch on side of divider 6,6 ′: Internal space of divider

7: air liquid exchange passage

7a: passageway forming an exchange passage of air liquid

7 ′: Air inflow passage 8,8 ′: Air suction pipe

9: ink return passage 10: ink reservoir

11: cylinder 13: central exit

15,16: cylindrical body and stopper constituting the partition container

17: cylindrical bottom opening 18: cylindrical body

18a: Circumferential nodal plane of cylindrical body

19a, 19b: narrowly spaced openings forming ink return passage

19c: Cutout of phase forming ink return passage

20: stopper of fibrous or porous body

G: Small interval w: Ink injected into the ink storage chamber

w ′: Compression chamber storage ink inside the partition

The present invention relates to a writing instrument using a low viscosity ink such as an aqueous ink.

Writing instruments using low-viscosity ink generally include a writing unit and an ink reservoir, which are connected to an ink passage so that ink in the ink reservoir is supplied to the writing portion, and the amount of ink consumed is controlled. By increasing the internal pressure of the ink storage chamber, the ink to be extruded is stored in the storage portion so that the stored ink is consumed later in writing so that the ink is not ejected to the outside.

As a representative example of such a structure, a writing pen mechanism of a fountain pen, such as that disclosed in Japanese Patent Laid-Open No. 42-7164, is known, but this is a cavity of a writing core formed to serve as an ink storage portion. When ink is extruded due to an increase in the internal pressure of the ink reservoir in the empty chamber, the ink stored in the cavity is consumed according to the writing, and the ink of the ink reservoir in the ink reservoir is kept at the bottom. Even if the internal pressure is lowered, air does not return to the ink storage chamber because air enters the ink storage chamber through the air distribution groove.

By the way, when the ink stored in the cavity is consumed by writing, it is extremely rare to consume all of the stored ink in the cavity in one writing, and in practice, ink often remains in the cavity at all times. For example, a fountain pen having an ink reservoir of about 1㏄ may be described as an example. If a total amount of ink is consumed, a writing distance of 500-1000m may be required. If the ink of the ink is stored in the cavity at once, 50-100 m must be written in order to exhaust the ink by writing.

However, the length of the fountain pen once drawn out and written is usually less than 1m, so the ink is often left in the cavity.

Therefore, in the conventional fountain pen based on the concept that the stored pressure must be consumed by writing, the pressure is increased, and the ink is pushed out again with the next increase in the pressure while the storage ink remains in the cavity of the writing part. If it is repeated over and over again due to repeated temperature changes, the amount of storage of the ink increases gradually, so-called drowning phenomenon of overflowing the ink occurs.

In particular, when a writing instrument having such a structure is used for an automatic drawing machine or a writing instrument for a recorder, the tip of the pen is always kept downward, so that the above dropping phenomenon has been the biggest drawback.

The present invention has been invented to solve the above drawbacks, and the first object of the present invention is to draw up the storage ink that is extruded according to the increase in the internal pressure of the ink storage chamber to lower the internal pressure of the ink storage chamber to be returned to the ink storage chamber. Therefore, to provide a writing instrument having a special structure so that the dropping phenomenon does not occur even in the pen down state.

It is a second object of the present invention to ensure that the ink is overflowing in any state of the writing instrument while holding or releasing the writing instrument or in any prevention state of the writing instrument so that the storage ink is reliably returned to the ink storage chamber according to the pressure drop of the ink storage chamber. It is to provide a writing instrument having a special structure prevented.

And, in order to achieve the first object of the present invention as described above, the writing instrument using the low-viscosity ink of the present invention is to install the writing unit, that is, the capillary wall inside the writing instrument body is strong, the writing style to absorb and store the ink Insert the ink into the writing unit to distribute the ink, and firmly insert the ink absorption storage unit into the opening of the partition container, so that the bottom becomes a partition wall with the writing unit body storage ink chamber, and at the same time the internal pressure of the ink storage room rises inside the partition container. A cylindrical partition container, which serves as an ink reservoir for storing the ejected ink, is inserted at a minute interval between the partition container and the inner wall of the writing instrument main body so that a capillary phenomenon is strongly applied between the inner wall of the writing instrument main body and the ink. Keep a small gap between the storage compartment and the ink absorption reservoir in the same way. To form an air / liquid exchange passage which acts as a valve which is normally closed by ink and opened to ink bleeding during writing, and the writing instrument body is not blocked by the stored ink as it exits into the compartment. It is characterized in that an air inlet vent is opened at a position.

In addition, in order to achieve the second object of the present invention as described above, in the composition of writing instruments for achieving the first object of the present invention, the bottom of the compartment or the side portion in contact with the bottom is always closed with ink to the interior of the compartment To prevent the air from entering the ink chamber and the ink stored in the compartment through the internal pressure rise of the ink storage chamber of the writing instrument body. Characterized in that the return passage is installed to act as a return.

Best Mode for Carrying Out the Invention Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment applied to a writing instrument used for writing, and shows a state before use without a low-viscosity ink in a longitudinal cross-sectional view, and FIGS. 2, 3, and 4 are shown in FIG. It is a partial cross section along the lines II-II, III-III, and IV-IV of FIG.

In these drawings, the writing instrument body 1 is in the form of a barrel having a circular cross section, and the writing portion 2 is provided at its distal end, and a stopper 3 that can be inserted into and removed from the rear end opening is closely attached. . In addition, the writing unit 2 is a bowl holder (2b), which is inserted into the holes at both ends of the writing instrument main body 1 while serving as a wrap-around so that the bowl 2a can be rolled freely. It consists of an ink relay wick 2c made of a fiber bundle inserted into the center hole communicating with the bowl support portion of the holder 2b and inward from the rear end portion of the holder. In addition to the writing unit, a fiber writing unit, a plastic gap porous writing unit, a pipe writing unit, or the like, which draws ink to the writing unit end through a strong capillary action, may be used.

The ink absorbing storage body 4 is inserted into the inner hole 1a of the writing unit 2 device portion of the writing instrument body 1, and the ink relay wick 2c of the writing unit 2 absorbs ink. The ink relay wick 2c is inserted into the center hole formed in the lower portion of the storage body 4 so that the ink penetrates down. When the ink is absorbed to the saturation state, the ink absorbing storage body 4 has a strong capillary action that can prevent the dropping of ink due to capillary action, adsorption force, adhesion force, etc. (However, the capillary action of the writing unit 2). Slightly weaker) An ink absorbent called a middle surface is used.

The partition container 5 is fixedly fitted inside the front end side of the writing instrument body 1, and the inside of the front end portion of the opening portion is in contact with the ink absorbing storage member 4, and the bottom side of the writing instrument body ink storage chamber 10 is provided. It becomes a partition wall and is in close contact with the inner wall surface of the writing instrument main body, and the inner space 6 of the partition tube is formed to serve as a storage chamber of ink drawn out by the capillary force of the pressure difference.

In addition, the outer diameter d of the compartment 5 is slightly smaller than the bottom outer diameter (same as the inner diameter of the main body) D, and is about 0.05 mm from the inner wall surface of the writing instrument body 1, rather than the capillary force of the ink absorption storage body 4. The microgap G is to be formed all around the joint so that a slightly weak capillary force is applied.

In addition, the outer surface of the partition barrel 5 is formed with a circumferential notch plane 5a cut out of a part of the circumference over the entire length, and the hole (both sides part) surrounded by the circumferential notch plane 5 and the main body inner wall surface The air-liquid exchange passage for contacting the writing body ink storage chamber 10 and the ink absorbing storage body 4 by a strong capillary tube and a central crescent hole having a weakly crescent-shaped hole in which the capillary tube is weakly applied. ) Is formed.

In addition, the exchange passage (7) is an ink absorbing storage body of the interior space (6) of the partition cylinder through the groove of the notch (5b) of the opening having a width smaller than the passage width provided in the front end opening of the partition cylinder (5). (4) It is opened near. The air intake tube 8 is for inflow of air installed at both ends of the writing instrument body 1 and penetrates a part of the ink absorbing body 4 and protrudes into the compartment inner space 6. The portion to be protruded inwardly is bent as shown in FIG. 1 so that the opening of the end of the vent pipe 8 for space suction escapes into the interior space 6 and is not blocked by the stored ink. It is open at the central position in the longitudinal and longitudinal directions.

The ink return passage 9 is close to the bottom of the compartment 5 and is opened to communicate with the micro-gap G on the side surface opposite to the air and liquid exchange passage 7 (the partition cylinder circumferential plane 5a). The return passage 9 is normally closed as shown in FIGS. 6, 14 and 15 due to the ink filling the micro-gap G, so that the air in the compartment inner space 6 is closed. Interfering with entering the writing body ink storage chamber 10 through the return passage (9), the internal pressure of the writing body ink storage chamber 10 in a pen up state as shown in FIG. In this case, the ink is discharged to the main body ink chamber 10 by the storage ink of the partition container inner space 6 (the ink flows out into the partition container internal space 6 due to the increase in the internal pressure of the writing instrument body ink storage chamber 10). Do it.

6, 7, 8, and 9 are explanatory diagrams showing the state when the low viscosity ink W is injected into the writing instrument body ink storage chamber 10 (FIGS. 1 and 2). And a portion of the ink W in the writing body ink storage chamber 10 in this state, in which the ink absorbing storage body 4 and the writing body portion 2 are formed. The ink absorbing storage body 4 is closed by the ink, which is sucked by the capillary action and filled with the air / liquid exchange passage 7 and the small gap G, and the exchange passage 7 and the return passage 9 are closed. The ink absorbs the ink to the saturation state, and the dropping of the ink is prevented by the capillary action, the adsorption force, and the adhesion force.

That is, when the ink absorption storage body 4 absorbs the ink W to the saturation state by capillary action, the ink weight and the internal pressure are balanced and stabilized.

At this time, when the head of the ink related to the overflow of ink is empty, when the inner space 6 of the compartment is empty, the ink falls out as shown in FIG. 14 due to the internal pressure rise in the minimum pressure head and the inner space 6 of the compartment. If it is shown, the maximum pressure head and the writing unit (2) and the ink absorbing storage (4), depending on the structure or material, but the writing unit (2) is a ball-point pen structure and drawings, the ink absorbing storage (4) Is a bundle of acrylic fibers, the maximum pressure head of the ink is allowed up to about 25 mm, the capacity of the writing instrument body ink storage chamber 10 in accordance with the guarantee temperature difference to be pressed by the maximum pressure head of the ink in the allowable range When the capacity ratio of the interior of the partition to the inner space 6 is set at a ratio of about 10: 2, for example, the ink is not dripped from the writing unit 2.

However, when the ink absorbed to the saturated state in the ink absorbing storage body 4 is consumed by writing in the writing unit 2, the ink absorbing storage body 4 has a margin for sucking ink, and thus has a small interval (G). Since the ink in the ink and the ink in the air / liquid exchange passage 7 are sucked in, the ink of the central portion having weak capillary action of the air / liquid exchange passage 7 is absorbed, and the center of the passage is shown in FIGS. 11 and 12. 13, an air inflow passage 7 'is formed, and through the air inflow passage 7', the air in the compartment interior space 6 passes through the writing body ink storage chamber as shown in FIG. 10) and the exchange of air and ink is made.

Then, when the ink absorption storage body 4 absorbs ink and becomes saturated again, the air and liquid exchange passage 7 (air inflow passage) opened as shown in FIGS. 10, 11, 12, and 13 7 ') is automatically blocked by the ink as shown in Figs. 6, 7, 8, and 9, and the air infiltration into the ink storage chamber 10 and the ink supply to the ink absorption storage body 4 are stopped.

FIG. 14 shows a state in which the writing instrument body ink storage chamber 10 has risen in internal pressure in a pen-down state, and in this case, the ink W in the ink storage chamber 10 passes through the air / liquid exchange passage 7 as a medium. The internal space air, which is extruded to (6) and equal to the amount of the stored ink (W '), is discharged to the outside through the vent pipe (8). At this time, the ink absorption reservoir (4) is saturated with ink. Since the ink is absorbed, the ink extruded due to the increase in the internal pressure of the ink storage chamber 10 is blocked from being pressed by the writing unit 2 and introduced into the partition container inner space 6. For this reason, the ink drop from the writing body 2 is reliably prevented by the internal pressure rise of the ink storage chamber 10.

FIG. 15 shows a state in which the ink W 'stored in the partition container inner space 6 is returned to the writing body ink storage chamber 10 as shown in FIG. In this case, when the internal pressure of the writing instrument body ink storage chamber 10 decreases due to the pressure drop, the storage ink W ′ of the compartment inner space 6 is sucked into the ink storage chamber 10 through the exchange passage 7. In addition, the external air, which has been replaced with this, is introduced into the partition tube inner space 6 through the vent pipe 8.

At this time, since the ink return passage 9 is closed by ink in the micro-gap G where a strong capillary action occurs, the storage ink W ′ is prevented from infiltrating the air into the ink passage of the compartment inner space 6. ) Can be efficiently sucked into the ink storage chamber (10).

FIG. 16 shows the state when the internal pressure of the ink storage chamber 10 is increased in the pen-up state. In this case, the ink in the air-liquid exchange passage 7 is extruded into the compartment-cylinder inner space 6, and the air and liquid The exchange passage (7) becomes an air flow hole, and the internal pressure flows out along the path of the air / liquid exchange passage (7) → partition interior space (6) → air intake passage (8). The problem of overflowing ink from the device does not occur.

FIG. 17 shows the storage ink W ′ of the partition container inner space 6 (the ink flowing in the pen down state as shown in FIG. 14 or the ink flowing in the pen state as shown in FIG. 19) in the pen up state. It shows the state to be returned to the ink storage chamber 10 in accordance with the internal pressure drop of the ink storage chamber 10, wherein the ink (W ') stored in the bottom of the partition barrel 5 is returned to the passage (9) → micro-interval (G) → It is sucked into the ink storage chamber 10 along the path of the exchange passage 7 of the air liquid, and is replaced with this, and the external air flows into the partition tube inner space 6 through the vent pipe 8.

18 and 19 show the ink storage chamber 10 in a state where the pen is laid down (FIG. 18 shows the ink return passage 9 at the lower side, and FIG. 19 shows the ink return passage 9 at the upper side). In the state shown in FIG. 18, the ink in the air / liquid exchange passage 7 is extruded into the partition cylinder internal space 6 by raising the internal pressure of the ink reservoir 10 in the state shown in FIG. The liquid exchange passage 7 becomes an air flow hole, and the internal pressure flows out along the path of the exchange passage 7 → the partition tube inner space 6 → the vent tube 8. Overflow does not occur.

In the state of FIG. 19, since the ink return passage 9 is above and the air / liquid exchange passage 7 is below, part of the ink W in the storage chamber is replaced by the increase in the internal pressure of the ink reservoir 10. It is extruded through the partition (7) into the partition inner space (6). At this time, the air in the compartment interior space (6) is discharged out through the vent pipe (8).

Therefore, even when the pen is in a lying state, the ink that escapes due to the increase in the internal pressure is stored in the compartment-cylinder inner space 6, so that it does not overflow from the writing unit 2 or the vent tube 8.

FIG. 20 shows the ink (W ') stored in the inner compartment 6 of the partition pail, the ink flowing in the pen downward state as shown in FIG. 14 or the ink flowing in the pen folded state as shown in FIG. Shows the state of returning to the ink storage chamber 10 due to the internal pressure drop of the ink storage chamber 10. In this state of FIG. 20, the air-liquid exchange passage 7 is above and the ink return passage is located below. In this state, when the internal pressure of the ink storage chamber 10 decreases in this state, the ink W 'stored in the partition vessel inner space 6 returns a minute capillary force strongly acting in the return passage 9. The space G is returned to return to the ink storage chamber 10 from the air / liquid exchange passage 7 (this return action is performed by the suction force due to the pressure drop).

At this time, the air-liquid exchange passage 7 attempts to be opened by suction force due to the internal pressure drop of the ink storage chamber 10, but the ink W 'stored in the partition vessel inner space 6 has a strong capillary action. Since it is supplied continuously so as not to be cut off in the middle through G), the opening does not occur until all of the storage ink W 'is sucked up (the air-liquid exchange passage 7 opens in the middle). The air is sucked into the ink storage chamber 10 through the passage opening to return the ink W ′ stored in the interior space 6 to the ink storage chamber 10. Is gone).

21, 22, 23, 24, and 25 show modifications of the above-mentioned partition barrel 5 and the above-mentioned return passage 9 formed in the partition barrel 5, 21 and 22, the cylindrical cylinder 15 has a cylindrical cutout surface 15a at its side and a cylindrical body 15 opened at both ends with a notch 15b at its end and the cylindrical body 15. As shown in FIG. A stopper 16 is inserted into the rear end opening of the 15, and a narrow gap opening 19a is located on the opposite side of the circumferential notch 15a to the engaging portion of the stopper 16 and the cylindrical body 15. 19b is formed and used as the return passage 9 of the storage ink W 'which is taken out.

23 shows a modified example when the ink return passage 9 is not provided in the partition container 5, and the writing instrument (self-operation device, Writing instruments such as recorders).

FIG. 24 is a deformation in which the return passage 9 is formed of a notch groove 19c shaped to tear apart from the end of the partition barrel opening to the floor on the opposite side of the side notch plane 5a of the partition barrel 5. For example, FIG. 25 shows a cylindrical tube 18 in which the partition tube 5 has an opening 17 in the bottom wall (a cylindrical circumferential plane 18a that forms an air-liquid exchange passage 7 on the side of the cylinder). And a cap (20) made of a fibrous or porous body having a strong capillary action force, which absorbs the ink that closes the opening 17 of the bottom wall of the cylindrical body 18, but blocks the air flow by the absorbed ink. And a return passage 9 in which the storage ink W 'is returned to the writing body ink storage chamber 10 by the stopper 20 and the opening 17 of the cylindrical bottom wall. It indicates.

26 is an enlarged sectional view of the main portion showing another embodiment of the air-liquid exchange passage 7 described above, wherein the air-liquid exchange passage 7 is a partition cylinder 5 of the writing instrument body 1, and the writing instrument body 1 is shown in FIG. One or several passage holes 7a are formed in the inner wall surface portion inserted into the inner wall surface, and strong capillary force is applied to both ends, and capillary force is weakly applied to the central portion.

27A and 27B show an embodiment in which the present invention is applied to a writing instrument for a recorder in which the writing unit 2 is always used in a downward state, and the writing unit main body 1 'having a large ink storage chamber 10 is integrated. (11) and a stopper (12) for closing the lower end of the tube (11), and the writing unit (2 ') is attached to the central projection (13) of the stopper (12). The ink absorbing reservoir 4 having a strong capillary action for supplying ink to the first ink absorber 4 is placed inside the central protrusion 18, and the primary ink absorbing reservoir 4a. ) And a secondary ink absorbing storage body 4b laid on the inner surface of the stopper 12 by surface contact.

And the inside of the writing implement body (1 ') is fixed to the inner wall surface of the cylindrical body 11 and the partition cylinder (5') of the cylindrical cylinder shape is fixed to have a small gap (G).

The partition container 5 'is formed by adhering the opening end surface to the secondary ink absorbing storage body 4b so that the bottom side thereof is a partition wall with the writing body ink storage chamber 10 on the inner wall surface of the cylindrical writing implement body 11. The inner space 6 'was formed to communicate with the air-liquid exchange passage 7 and the micro-gap G so as to be a storage chamber for the ink that came out of the space.

In addition, the main body 12 is provided with an air intake vent 8 'which penetrates through the secondary ink absorbing reservoir 4b and protrudes into the partition inner space 6'. The end of the vent tube 8 'is provided. Is opened on the upper side which is not blocked by the storage ink of the internal space 6 '.

In addition, since the operation | movement of this embodiment is substantially the same as the operation | movement shown to FIG. 6 thru | or 12 which is 1st Embodiment mentioned above, description is abbreviate | omitted.

The writing instrument of the present invention has the structure as described above, and when the ink extruded due to the increase in the internal pressure of the ink storage chamber is temporarily stored in the inner space of the compartment, the storage ink is returned to the ink storage chamber by the pressure drop occurring after the increase in the pressure resistance. As a result, no overflow of ink from the handwriting occurs.

Particularly, in the case of the writing instrument described above, the above-described effect can be achieved even if the writing unit is held or placed in any direction, such as upward or horizontal, thereby exhibiting an excellent effect as a hand-written writing instrument.

Claims (9)

In a writing instrument using low-viscosity ink, the ink absorbing storage body 4 is inserted into the writing body portion 2 and the ink absorbing storage body 4 is connected to the inside of the writing body portion 2 installation portion of the writing instrument body 1, and the ink absorption storage is performed. Contacting the sieve 4 with the cutout portion 5b of the opening of the partition barrel 5 so as to make a partition with the main body ink storage chamber 10, and at the same time, the inner space 6 has a storage chamber for the Inserting and fixing the partition container 5 so as to have the inner wall surface of the main body 1 and the small gap G so as to communicate between the ink storage chamber 10 and the ink absorbing storage member 4 for ink extraction during writing. The air-liquid exchange passage 7 is opened so that the air passage is formed, and the air intake tube 8 is installed in the writing instrument body 1 by opening it in a position where it is not blocked by ink stored in the compartment space 6. Writing instruments. The air-liquid exchange passage is formed over the entire length of the outer surface of the partition vessel 5, and the central portion is one or several passages 7 ', and its tip is formed in the partition cylinder internal space 6. The pen is opened via a notch. 2. The capillary tube according to claim 1, wherein an air / liquid exchange passage (7) is formed in the inner wall surface portion where the writing instrument body (1) sandwiches the partition cylinder (5), and is strong at both ends of the air / liquid exchange passage (7). Writing device, characterized in that one or several passages (7 ') that the force acts and the central capillary force acts. The size of the handwriting ink absorbent storage medium according to claim 1, wherein each capillary force acting on the writing unit (2), the ink absorbing storage body (4), the microgap (G), and the air / liquid exchange passage (7) A writing instrument, characterized by a change from the strongest to the weakest in the order of the interval air liquid exchange passage. In writing instruments using low-viscosity ink, it is always closed with ink on the bottom or outer surface of the compartment 5 to prevent the air in the compartment 6 from entering the ink storage chamber 10; The ink return passage 9 which acts to return the ink flowing into the compartment interior space 6 due to the increase in the internal pressure of the writing instrument body ink storage chamber 10 toward the ink storage chamber 10 when the internal pressure of the ink storage chamber 10 is lowered. Writing instruments with features). The writing instrument as set forth in claim 5, wherein the ink return passage (9) is located near the bottom of the compartment (5) and is opened to communicate with a small gap (G) on the outer surface of the air-liquid exchange passage (7). . 6. The partition container (5) is composed of a cylindrical body (15) having both ends opened and a stopper (16) sandwiched in the rear end of the cylindrical body (15), and the stopper (16) and the cylindrical body (15). The writing instrument characterized in that a narrow gap opening is provided on the opposite side of the air / liquid exchange passage (7) to become a return passage (9) of the storage ink. The writing instrument according to claim 5, wherein the return passage (9) is formed on the outer surface opposite the air / liquid exchange passage (7) so as to be separated from the opening of the partition barrel (5) to the vicinity of the bottom. The stopper (16) of the cylindrical body (15) according to claim 5, wherein the stopper (16) made of a fibrous body or a porous body which blocks the air flow by the ink absorbed by blocking the bottom opening 17 formed at the bottom of the partition container 5 is absorbed. It is inserted into the rear end portion, the writing instrument characterized in that the bottom opening portion 17 of the stopper (16) and the partition barrel (5) is formed as a return passage (9) of the ink.

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