JP2014188969A - Writing utensil containing fresh ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a writing utensil containing fresh ink capable of accurately preventing ink leakage.SOLUTION: In the writing utensil containing fresh ink, an inner cylindrical body 2, in which an ink occlusion body 3 is stored, is fitted into a cylindrical main body 1 to make a space between both bodies as an ink tank 4, and ink in the ink tank 4 is supplied through an ink supply hole 2b, formed on a wall face of the inner cylindrical body 2, to the ink occlusion body 3 and a pen lead 5 mounted on the apex part of the body 3. The ink occlusion body 3, when viewed from a cross-section perpendicular in an axial direction, is constituted of a multilayer structure in which a layer 3a with a dense fiber structure is formed at the center part and a layer 3b with a rough fiber structure is formed on the outer periphery. Further, in the vicinity of the rear end portion of the pen lead 5 in an axial direction of the pen lead 5 of the ink occlusion body 3 is formed a portion with a dense fiber structure, and the ink supply hole 2b is opened toward the portion with a dense fiber structure in the axial direction of the ink occlusion body 3.

Description

  The present invention relates to a writing instrument with a built-in raw ink that can accurately prevent ink leakage.

Conventionally, raw ink-containing writing instruments containing water-based, oil-based ink for writing instruments, ink for jet printers, and the like have been widely used. As a function of this writing instrument, it is required that the discharge amount is stable and that the discharge is stable without ink leakage or dripping even if the usage environment conditions such as temperature and pressure change. Yes.
Note that the writing instrument in the present invention does not mean only the above-mentioned water-based and oil-based writing instruments, but includes, for example, a poster applicator or a correction liquid applicator that can be applied over a wide area, and a cosmetic liquid or It also includes an applicator for applying a medicine or the like (hereinafter referred to as a writing instrument).

  As such a raw ink built-in writing instrument, an inner cylinder body in which a rear end is closed and an ink occlusion body is accommodated is inserted into a cylindrical body, and an ink tank is formed between the two. An ink occlusion body and a pen core attached to the tip side of the ink occlusion body are known through an ink supply hole formed on the wall surface of the inner cylinder (see, for example, Patent Document 1 and Patent Document 2). .

  In the above-described Patent Document 1 and Patent Document 2, an ink occlusion body is used, and a special connection hole and a gap for adjusting the capillary action are provided to stabilize the discharge amount. However, in the above, the fiber structure of the ink occlusion body is composed of a dense portion and a rough portion when viewed in the axial direction, and the rough portion is arranged on the rear side of the dense portion, and the ink is placed on the front side. There is a problem that ink leakage from the pen core is likely to occur because there is no part that disperses and absorbs ink, and there is a problem that the air flow path must pass through the back side of the ink occlusion body, which complicates the structure. It was. As a result, there has been a problem that when the use environment conditions such as temperature and pressure change, the ink overflows and ink leaks from the pen core. In addition, it is necessary to provide special connection holes and gaps, which causes a problem that processing and assembly are complicated and production cost is increased.

  On the other hand, as shown in Patent Document 3 and Patent Document 4, from a multilayer structure in which a dense layer of fiber structure is formed as an ink occlusion body, and a coarse layer of fiber structure is formed on the outer periphery via an adhesive. What is known. However, those described in Patent Document 3 and Patent Document 4 are intended to keep the ink uniformly in the entire dense layer of the central fiber structure, and ink leakage is not considered at all. Moreover, it is not assumed to be used for raw ink, and when raw ink is used, the entire ink occlusion body is uniformly filled with ink, and there is a problem that ink leakage and dropping off occur.

Japanese Patent No. 3931722 Japanese Patent Publication No. 7-45271 Japanese Utility Model Publication No. 60-9686 Japanese Utility Model Publication No. 47-5642

  The present invention solves the above-mentioned problems, and even when changes occur in the use environment conditions such as temperature and pressure, the ink is appropriately dispersed and absorbed to accurately prevent ink leakage from the pen core. It was completed for the purpose of providing a writing instrument with a built-in raw ink that can be prevented, that is simple in structure, can be easily processed and assembled, and can reduce production costs. is there.

  The writing instrument with a built-in raw ink according to the present invention, which has been made to solve the above-mentioned problems, has an inner cylinder body in which a rear end is closed and an ink occlusion body is accommodated in a cylindrical main body, A writing instrument with a built-in raw ink, wherein the ink is supplied to an ink storage body and a pen core attached to the tip end of the ink tank through an ink supply hole formed in the wall surface of the inner cylinder. When the occlusion body is viewed in a cross section perpendicular to the axial direction, it has a multilayer structure in which a dense layer of fiber structure is formed at the center and a coarse layer of fiber structure is formed at the outer periphery. A dense fiber structure is formed in the vicinity of the rear end of the pen core of the occlusion body, and the ink supply holes are opened toward the dense fiber structure in the axial direction of the ink occlusion body. Is.

  It is preferred that the fiber occlusion body has a coarse fiber texture formed on the front side of the dense fiber texture in the axial direction, and this is the invention according to claim 2.

  The portion where the fiber structure in the axial direction of the ink occlusion body is dense is formed by compression by a recess provided on the wall surface of the inner cylinder, and an ink supply hole is formed on the bottom surface of the recess. This is preferable, and this is the invention according to claim 3.

  Moreover, it is preferable that the said recessed part is partially formed in the circumferential direction of the wall surface of an inner cylinder, and let this be the invention which concerns on Claim 4.

  The ink occlusion body, when viewed in the axial direction, preferably has a fiber structure arranged in order of a rough portion, a dense portion, and a rough portion from the tip side, and this is the invention according to claim 5.

  Alternatively, when viewed in the axial direction, the ink occlusion body preferably has a fiber structure arranged in order of a rough portion, a dense portion, and a dense portion from the tip side, and this is the invention according to claim 6. To do.

In the invention according to claim 1, an inner cylinder body in which the rear end is closed and an ink storage body is accommodated in the cylindrical main body is inserted, and an ink tank is formed between the two. A raw ink built-in writing instrument that is supplied to an ink occlusion body and a pen core attached to the tip side of the ink occlusion body through an ink supply hole formed in a wall surface of the cylinder, wherein the ink occlusion body is cross-section perpendicular to the axial direction. In this case, it has a multilayer structure in which a dense layer of fiber structure is formed at the center and a coarse layer of fiber structure is formed at the outer periphery, and the pen is inserted in the axial direction of the pen core of the ink occlusion body. A portion where the fiber structure is dense is formed in the vicinity of the rear end of the core, and the ink supply hole is opened toward the portion where the fiber structure in the axial direction of the ink occlusion body is dense. Ink is the fiber structure in the center of the ink occlusion body. It is well absorbed in a layer and thus being stored. Furthermore, since a dense fiber structure is formed in the vicinity of the rear end of the pen core, ink can be supplied to the pen core more stably.
On the other hand, even when changes occur in environmental conditions such as temperature and pressure, a rough layer of fiber structure is formed on the outer periphery, so that excess ink is dispersed and absorbed in this rough portion. Leakage is accurately prevented. In addition, the air flow path does not necessarily have to pass through the rear side of the ink occlusion body as in the conventional case, and air can be circulated also from the front side, and a simple structure can be achieved.

  In the invention according to claim 2, since the fiber structure has a rough portion on the front side of the dense portion of the axial direction of the ink occlusion body, excess ink is dispersed and absorbed in the rough portion. As a result, ink leakage is accurately prevented.

  In the invention according to claim 3, the portion where the fiber structure in the axial direction of the ink occlusion body is dense is formed by compression by a recess provided in the wall surface of the inner cylinder, and the bottom surface of the recess has ink. Since the supply hole is formed, it is possible to easily form a dense portion of the fiber structure simply by inserting the ink occlusion body into the inner cylinder. In addition, the structure is simple, and processing and assembly operations can be easily performed.

  In the invention according to claim 4, since the recess is partially formed in the circumferential direction of the wall surface of the inner cylindrical body, when viewed in a cross section perpendicular to the axial direction, a dense fiber structure is formed in the center. A layer is formed, and a rough layer of the fiber structure is partially formed on the outer peripheral portion, and ink leakage from the pen core can be prevented by dispersing and absorbing excess ink in this rough portion. . In addition, when the recess is partially provided, a gap is generated between the outer peripheral surface of the ink occlusion body and the inner peripheral surface of the inner cylindrical body, so that it is not necessary to separately secure an air flow path.

  In the invention according to claim 5, the ink occlusion body, when viewed in the axial direction, the fiber structure is arranged in the order of the coarse portion, the dense portion, and the coarse portion from the tip side, so that the ink storage in the dense portion. Even if the amount is exceeded, the ink (surplus ink) in which the rough portions of the fiber structures on the front side and the back side overflow is dispersed and absorbed, and ink leakage from the pen core is prevented.

  On the other hand, in the invention according to claim 6, the ink occlusion body, when viewed in the axial direction, the fiber structure is arranged in the order of the coarse portion, the dense portion, and the dense portion from the tip side. The ink storage amount can be greatly increased. On the other hand, if there is a change in the environmental conditions of use, a rough portion of the fiber structure is formed on the front side of the dense portion, and this rough portion disperses and absorbs the ink to accurately prevent ink leakage. Will be prevented.

It is sectional drawing which shows embodiment of this invention. It is sectional drawing which shows the principal part of FIG. It is explanatory drawing which shows the state of the ink occlusion body in FIG. It is a front view of an inner cylinder. (A) is AA sectional drawing in FIG. 1, (b) is explanatory drawing which shows the state of the ink occlusion body. It is sectional drawing which shows other embodiment. It is sectional drawing which shows the principal part of FIG. It is explanatory drawing which shows the state of the ink occlusion body in FIG. It is a perspective view which shows an ink occlusion body. It is BB sectional drawing in FIG.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of the present invention. In the figure, 1 is a bottomed cylindrical main body, and 2 is an inner cylindrical body that is fitted into the cylindrical main body 1. The inner cylinder 2 is closed at the rear end by a plug 2a, and accommodates an ink occlusion body 3 made of so-called batting or sponge in which polyester, acrylic fiber or the like is focused. A fixed space is formed between the cylindrical main body 1 and the inner cylindrical body 2 to form an ink tank 4, and the ink (liquid raw ink) in the ink tank 4 is transferred to the inner cylindrical body 2. It has a structure in which it is supplied to the ink occluding body 3 and the pen core 5 attached to the front end side thereof through the ink supply hole 2b formed on the wall surface. The positions where the ink supply holes 2b are provided will be described later.

As shown in FIGS. 9 to 10, the ink occlusion body 3 is formed with a dense layer 3 a of the fiber structure at the center and a coarse structure of the fiber structure at the outer periphery when viewed in a cross section perpendicular to the axial direction. It has a multi-layer structure in which a simple layer 3b is formed.
With such a multilayer structure, the ink supplied from the ink supply hole 2b can be sufficiently absorbed and stored in the dense layer 3a of the fiber structure at the center of the ink occlusion body 3, and the pen core 5 can be supplied stably.

In FIG. 1, reference numeral 6 denotes a neck seat for fixing the pen core 5.
The neck 6 holds the pen core 5 so that the front end portion of the pen core 5 is exposed to the outside, and the rear end portion is pushed into the ink occlusion body 3 and buried. Due to the pressing of the pen core 5, a portion in which the fiber structure is dense (in the case of a sponge, the density is high) is formed in the vicinity of the rear end portion of the pen core 5.
An air flow path is formed on the inner surface of the neck 6 that holds the pen core 5. When the air in the ink tank 4 expands and the ink forcibly flows into the ink occlusion body 3 from the ink supply hole 2b, the air flow path causes the air pushed out by the ink flowing into the ink occlusion body 3 to the outside air. This is a configuration necessary for being discharged.
Further, the tip of the pen core 5 is the same as the conventional one in that it can be opened and closed by a cap (not shown).

  As described above, the ink occlusion body 3 has a dense fiber structure formed in the vicinity of the rear end portion of the pen core 5 in the axial direction of the pen core 5, and a fiber structure on the front side of the dense portion. Has a structure in which a rough portion is formed. The dense part and the rough part mean a relative relationship, and the dense part has a denser fiber structure than the coarse part. A lot of ink will be collected.

As shown in FIG. 2, the wall surface of the inner cylindrical body 2 is provided with a pair of dent portions 2 c across the center point. Due to the recess 2c, the corresponding portion of the ink occlusion body 3 is compressed toward the center, and a dense structure of the fiber structure is formed.
The ink supply hole 2b is provided on the bottom surface of the recess 2c, and the fiber structure of the ink occlusion body 3 is opened toward a dense portion. As a result, the ink in the ink tank 4 is replenished toward a dense portion of the fiber structure, and this dense portion is always filled with ink to supply ink to the pen core 5 stably. Become. As a result, a stable ink discharge amount is secured from the pen core 5.

FIG. 4 is a front view of the inner cylinder 2, and FIG. 5 is an AA cross-sectional view in FIG. 1 and an explanatory diagram of the state of the ink occlusion body. In the illustrated example, the recessed portion 2 c is partially formed in the circumferential direction of the wall surface of the inner cylindrical body 2. Specifically, a pair is provided in the diameter direction, but it is needless to say that three or more may be provided.
By providing the recess 2c partially rather than the entire circumference, when viewed in a cross section perpendicular to the axial direction, a dense layer of fiber structure is formed at the center, and a coarse layer of fiber structure is partially formed at the outer periphery. Therefore, the excess ink can be dispersed and absorbed even in this rough portion, and ink leakage from the pen core can be prevented.
In addition, “a part of the recess 2c is provided with a gap (see FIG. 5A) between the outer peripheral surface of the ink occlusion body 3 and the inner peripheral surface of the inner cylindrical body 2, and therefore a separate air flow path. This air flow path allows the ink that has flowed into the ink occlusion body 3 when the air in the ink tank 4 expands and ink forcibly flows into the ink occlusion body 3 from the ink supply holes 2b. This is a configuration necessary for the air pushed out by the air to be discharged to the outside air, and not only the ink tank 4 but also the air pushed out by the expansion of the air in the inner cylinder 2 or the ink storage body 3. This configuration is also necessary for discharging to the outside air.

  If the replacement of ink and air can be performed smoothly and smoothly, the shape, size and number of ink supply holes 2b, ink type (oil and water), viscosity, and surface tension should be appropriately optimized. It can be adopted.

The flow of air and ink will be described below.
In the present invention, the ink flows out from the ink supply hole 2b to the ink occlusion body 3 when assembled. Due to the outflow of ink, the air corresponding to the reduced amount of ink flows into the ink tank 4 from the ink storage body 3 at the same time, and the ink and air are replaced between the ink tank 4 and the ink storage body 3. When the inflow of air into the ink tank 4 and the outflow of ink into the ink storage body 3 reach equilibrium, the outflow of ink into the ink storage body 3 through the ink supply holes 2b is stopped.
When the ink that has flowed out to the ink storage 3 is consumed by writing, the outside air taken in from the air flow path provided on the inner surface of the neck 6 passes through the ink storage 3 and is supplied from the ink supply hole 2b to the ink tank. 4, when the ink is exchanged and flows out through the ink supply hole 2b to the ink occlusion body 3 until the ink reaches a position where the ink supply hole 2b is blocked, the air is no longer present. It becomes impossible to pass through the ink supply hole 2b, and as a result, the outflow of the ink to the ink occlusion body 3 is stopped.
As described above, the ink supply hole 2b has a valve function for the flow of ink and air, and prevents the ink from being excessively supplied to the ink occlusion body 3, and always supplies a certain amount of ink to the ink occlusion body 3. It serves to supply. That is, the ink flows out to the ink occlusion body 3 by the inflow amount of air.

In addition, when the pressure of the air in the ink tank 4 is higher than the atmospheric pressure, the ink overflowing from the ink supply hole 2b (surplus ink) is caused by the rough portion of the ink occlusion body 3. It is absorbed quickly.
This is because the ink is hardly absorbed by the rough portion of the ink occlusion body 3 during normal times, and the rough portion of the ink occlusion body 3 can always secure a space where the ink can be absorbed. Therefore, even if the air in the ink tank 4 expands and the ink forcibly overflows from the ink supply hole 2b, the overflowed ink (surplus ink) is absorbed by the rough portion of the ink occlusion body 3, so that the pen Ink spillage from the core 5 can be prevented. At this time, the air in the inner cylindrical body 2 pushed out by the ink absorbed by the rough portion of the ink occlusion body 3 is discharged to the outside air through the air flow path, and ink drop off from the pen core 5 can be prevented.

  On the other hand, when the air in the ink tank 4 is compressed again, the ink that has flowed into the rough portion of the ink occluding body 3 is sucked back by the reduced pressure in the ink tank 4, so that the rough portion of the ink occluding body 3 again becomes the ink. Thus, even if the air in the ink tank 4 is repeatedly expanded and compressed, ink leakage does not occur.

Next, the relationship of the density of the fiber structure of the ink occlusion body 3 is shown.
As shown in FIG. 3, the ink occlusion body 3 has a portion having a coarse fiber structure in the axial direction from the front end side where the pen core 5 is located to the rear end side where the bottom portion of the cylindrical main body 1 is located. It has a structure in which the part and the rough part are arranged in this order.
In this case, since sufficient ink is always stored in a portion where the fiber structure is dense and is supplied to the pen core 5, stable writing quality can be ensured. On the other hand, even if the fiber structure exceeds the amount of ink stored in dense areas due to changes in environmental conditions such as temperature and pressure, the ink that overflows the rough areas of the front and rear fiber structures (excess ink) Is immediately dispersed and absorbed, so that ink leakage from the pen core 5 can be prevented accurately.

  In addition, in the vicinity of the crossing portion of the line connecting the axial direction of the pen core 5 and the ink supply hole 2b, a compression force in two directions, that is, compression by pushing the pen core 5 and compression by the recessed portion 2c is applied. The tissue becomes dense and the closest part is formed. As a result, sufficient ink is stored in the closest portion, and a more stable supply of ink is guaranteed.

As shown in FIG. 5A and FIGS. 9 to 10, the ink occlusion body 3 is formed with a dense layer 3 a of fiber structure at the center when viewed in a cross section perpendicular to the axial direction, and the outer peripheral portion. And a multilayer structure in which a rough layer 3b having a fiber structure is formed. As a result, a difference in capillary force is generated on the surface perpendicular to the axial direction, and more ink is collected in the central portion where the fiber structure is dense. Although the present embodiment shows a two-layer structure, it is needless to say that a multilayer structure having a three-layer structure or more may be used.
This structure has an advantage that the ink supply speed can be controlled at the position 3b1 that contacts the ink supply hole 2b. That is, the shape, size, and number of installed ink supply holes 2b are changed by adjusting the balance of the material and basis weight (weight per unit area) of the dense layer 3a and the coarse layer 3b of the fiber structure. In addition, the ink supply speed can be controlled. This means that it is possible to deal with various inks without changing the mold by simply changing the ink occlusion body 3 having a multilayer structure.
Further, this structure can disperse and absorb excess ink at the position 3b2 other than the contact with the ink supply hole 2b. That is, when viewed in a cross section perpendicular to the axial direction, this structure has a multilayer structure in which a dense layer 3a of fiber structure is formed at the center and a rough layer 3b of fiber structure is formed at the outer periphery. Further, the excessive ink can be dispersed and absorbed also in the coarse layer 3b of the fiber structure provided on the outer peripheral portion, and ink leakage from the pen core can be more effectively prevented.
Further, as shown in the drawing, when the recessed portion 2c is partially formed in the circumferential direction of the wall surface of the inner cylindrical body 2, the position 3b1 in contact with the ink supply hole 2b is a position 3b2 other than in contact with the ink supply hole 2b. Since the fiber structure becomes denser, the ink collects at the position 3b1 in contact with the ink supply hole 2b, and the excess ink is dispersed and absorbed at the position 3b2 other than the position in contact with the ink supply hole 2b, thereby causing ink leakage from the pen core. Can be prevented more effectively.

Next, FIG. 6 shows another embodiment.
In the structure shown in FIG. 6, the ink occlusion body 3 is moved from the front end side where the pen core 5 is located toward the rear end side where the bottom portion of the cylindrical main body 1 is located. The structure is arranged in the order of the parts. FIG. 7 shows a cross-sectional view of the main part, and FIG. 8 shows an explanatory diagram of the state of the ink occlusion body.

  In the structure shown in FIG. 6, a concave portion 2 c is provided on the wall surface of the inner cylindrical body 2 from the front portion toward the rear end in a band shape, and the ink occlusion body 3 at a corresponding position is provided by the concave portion 2 c. It is a structure in which a dense portion of the fiber structure is formed by being compressed in the central direction. In addition, an ink supply hole 2b is provided on the bottom surface of the front portion of the recess 2c, and the fiber structure of the ink occlusion body 3 is opened toward a dense portion.

In this case, the dense portion has a large volume that extends from the recessed portion 2c to the rear end of the inner cylinder 2, and the ink storage amount can be greatly increased. Can be secured. On the other hand, even when a change occurs in the use environment condition and the fiber structure that the pen core 5 is in contact with exceeds the amount of ink stored in the dense part, the coarse part of the fiber structure is present on the front side of the dense part of the fiber structure. Since the ink is formed, the ink (surplus ink) overflowing from the rough portion is dispersed and absorbed, and ink leakage from the pen core 5 is accurately prevented.
In addition, in the vicinity of the crossing portion of the line connecting the axial direction of the pen core 5 and the ink supply hole 2b, a compression force in two directions, that is, compression by pushing the pen core 5 and compression by the recessed portion 2c is applied. It is the same as in the first embodiment in that the tissue becomes dense and the closest part is formed.

The ink occlusion body 3 composed of a portion having a coarse fiber structure and a dense portion in the axial direction as described above can be easily formed by simply pushing a columnar fiber material formed into a uniform fiber structure into the inner cylinder 2. can do.
That is, when the fiber material is pushed into the inner cylinder 2, the corresponding portion is compressed in the center direction by the recess 2 c provided on the wall surface of the inner cylinder 2, and the tip side of the fiber material is the pen side. The core 5 is compressed by being pushed in. By such a compressing action, the fiber structure forms a dense portion in the vicinity of the rear end portion of the pen core 5 in the axial direction of the pen core 5 of the ink occlusion body 3, and the fiber structure is formed on the front side of the dense portion. A rough portion can be formed.

  In the configuration as described above, the ink supplied from the ink supply hole is sufficiently absorbed and stored in the dense portion of the fiber structure, and as a result, the ink is stably supplied to the pen core. In addition, since the fiber structure around the pen core is rough and the amount of ink stored is small, ink leakage does not occur from the pen tip. On the other hand, even when the usage environment conditions such as temperature and pressure are changed, a rough portion of the fiber structure is formed on the front side of the dense portion, so that the ink is dispersed and absorbed in the rough portion. As a result, ink leakage is accurately prevented.

DESCRIPTION OF SYMBOLS 1 Cylindrical main body 2 Inner cylinder 2a Plug 2b Ink supply hole 2c Recess 3 Ink occlusion body 3a Dense layer 3b of fiber structure Rough layer of fiber structure
3b1 Position where the coarse layer of the fiber structure contacts the ink supply hole
3b2 Position other than the contact with the ink supply hole in the coarse layer of the fiber structure 4 Ink tank 5 Pen core 6 Neck

Claims (6)

  An ink in which an inner cylinder body in which the rear end is closed and an ink occlusion body is accommodated is inserted into the cylindrical main body, and an ink tank is formed between the two, and the ink of this ink tank is formed on the wall surface of the inner cylindrical body A writing instrument with a built-in raw ink that is supplied to the ink occlusion body through the supply hole and the pen core attached to the tip of the ink occlusion body. When the ink occlusion body is viewed in a cross section perpendicular to the axial direction, a fiber is formed at the center. A dense layer of tissue is formed, and a multilayer structure in which a coarse layer of fiber structure is formed on the outer peripheral portion, and a portion where the fiber structure is dense is formed near the rear end of the pen core of the ink occlusion body. A raw ink built-in writing instrument, wherein the ink supply hole is formed and opened toward a portion where an axial fiber structure of the ink occlusion body is dense.   The writing instrument with a built-in raw ink according to claim 1, wherein a rough portion of the fiber structure is formed in front of a dense portion of the axial direction of the ink occlusion body.   The portion where the fiber structure in the axial direction of the ink occlusion body is dense is formed by compression by a recess provided on the wall surface of the inner cylinder, and an ink supply hole is formed on the bottom surface of the recess. Claim | item 1 or the raw ink built-in writing instrument of Claim 2.   4. The raw ink built-in writing instrument according to claim 3, wherein the dent is partially formed in a circumferential direction of the wall surface of the inner cylindrical body.   The raw ink built-in writing instrument according to any one of claims 2 to 4, wherein the ink occlusion body has a fiber structure arranged in order of a rough portion, a dense portion, and a rough portion from the tip side when viewed in the axial direction.   The raw ink built-in writing instrument according to any one of claims 2 to 4, wherein the ink occlusion body is arranged in the order of a rough portion, a dense portion, and a dense portion from the front end side when viewed in the axial direction.