JP4460992B2 - Direct liquid writing instrument - Google Patents

Description

  The present invention relates to a direct liquid writing instrument. More specifically, the present invention relates to a direct liquid type writing instrument in which an ink reservoir portion of an ink reservoir member is fitted into a front end opening of a shaft cylinder. In the present invention, “front” refers to the pen tip side, and “rear” refers to the ink tank side.

  Conventionally, in this type of direct liquid writing instrument, a synthetic resin ink retaining member is fitted into the front end opening of the shaft tube, and the collar portion of the ink retaining member is brought into contact with the front end of the shaft tube. It has been. (For example, Patent Document 1)

  In the conventional direct liquid writing instrument, as shown in FIG. 9, the ink reservoir portion of the ink reservoir member is fitted into the front end opening of the shaft cylinder 10, and is positioned in front of the ink reservoir portion of the ink reservoir member. When the flange portion 11 to be brought into contact with the front end of the shaft tube 10, the flange portion 11 is slightly bent forward from the base end portion 12, and a whitening phenomenon occurs in the base end portion 12 of the flange portion 11. May occur. When the ink reservoir member is formed of a transparent synthetic resin, the ridge portion also has transparency, so the whitening phenomenon is easily visible from the outside, and the appearance may be impaired.

  In particular, as the axial thickness of the flange portion becomes thinner or the radial length of the flange portion becomes longer, the flange portion tends to bend and deform due to contact with the front end of the shaft cylinder, and the whitening phenomenon Is likely to occur.

Japanese Utility Model Sho 61-45191

  The present invention solves the above-described conventional problems, and prevents the whitening phenomenon from occurring in the collar portion of the ink retaining member, and the appearance of the front portion of the transparent ink retaining member exposed to the outside It is an object of the present invention to provide a direct liquid type writing instrument in which there is no risk of damage.

The present invention is characterized by the following requirements.

(Claim 1)
An ink storage member is provided between the ink tank for storing ink directly and the pen tip to temporarily hold the overflow ink that accompanies an increase in pressure in the ink tank, and the ink storage member stores the overflow ink. Temporarily holding the ink reservoir, a straight tubular axial center projecting forward of the ink reservoir, and a flange projecting radially outward from the outer peripheral surface of the axial central A formed synthetic resin member, wherein the ink tank is provided in a shaft cylinder, an ink storage portion of the ink storage member is fitted into a front end opening of the shaft cylinder, and the collar portion is connected to the shaft cylinder. The ink storage member is made of a transparent synthetic resin and is exposed to the outside from the front end of the shaft tube, and is formed of a transparent synthetic resin. A direct liquid-type writing instrument characterized by having a built-up portion on the front and rear surfaces.

(Claim 2)
An ink storage member is provided between the ink tank for storing ink directly and the pen tip to temporarily hold the overflow ink that accompanies an increase in pressure in the ink tank, and the ink storage member stores the overflow ink. Temporarily holding the ink reservoir, a straight tubular axial center projecting forward of the ink reservoir, and a flange projecting radially outward from the outer peripheral surface of the axial central A formed synthetic resin member, wherein the ink tank is provided in a shaft cylinder, an ink storage portion of the ink storage member is fitted into a front end opening of the shaft cylinder, and the collar portion is connected to the shaft cylinder. The ink storage member is made of a transparent synthetic resin and is exposed to the outside from the front end of the shaft tube, and is formed of a transparent synthetic resin. A direct liquid writing instrument, characterized in that a rear surface is provided with a built-up portion.

(Claim 3)
An ink storage member is provided between the ink tank for storing ink directly and the pen tip to temporarily hold the overflow ink that accompanies an increase in pressure in the ink tank, and the ink storage member stores the overflow ink. Temporarily holding the ink reservoir, a straight tubular axial center projecting forward of the ink reservoir, and a flange projecting radially outward from the outer peripheral surface of the axial central A formed synthetic resin member, wherein the ink tank is provided in a shaft cylinder, an ink storage portion of the ink storage member is fitted into a front end opening of the shaft cylinder, and the collar portion is connected to the shaft cylinder. The ink storage member is made of a transparent synthetic resin and is exposed to the outside from the front end of the shaft tube. A direct liquid type writing instrument characterized by having a built-up part on the front.

(Claim 4)
4. The direct liquid writing instrument according to claim 1, wherein the build-up portion is formed in an annular shape on the outer peripheral surface of the shaft center portion and has a C-chamfered longitudinal section.

(Claim 5)
The direct liquid writing instrument according to claim 4, wherein the chamfer dimension of the recording overlay is 0.3 mm to 1.0 mm.

(Claim 6)
4. The direct liquid writing instrument according to claim 1, wherein the build-up portion is formed in an annular shape on the outer peripheral surface of the shaft center portion, and has a longitudinal cross-sectional shape of an R chamfer.

(Claim 7)
The direct liquid writing instrument according to claim 6, wherein an R chamfer dimension of the build-up portion is 0.3 mm to 1.0 mm.

According to the first aspect, the whitening phenomenon is prevented from occurring in the collar portion of the ink retaining member, and the appearance of the front portion of the transparent ink retaining member exposed to the outside is not impaired.

According to the second aspect, the whitening phenomenon is prevented from occurring in the collar portion of the ink retaining member, and the appearance of the front portion of the transparent ink retaining member exposed to the outside is not impaired.

According to the third aspect, it is possible to prevent the whitening phenomenon from occurring in the collar portion of the ink retaining member, and there is no possibility that the appearance of the front portion of the transparent ink retaining member exposed to the outside is impaired.

According to the fourth aspect, the strength against bending deformation of the collar portion is further improved, and the occurrence of the whitening phenomenon is suppressed.

According to the fifth aspect, the collar portion is sufficiently reinforced, and the occurrence of the whitening phenomenon can be sufficiently suppressed. Furthermore, when the built-up portion is provided on the front surface of the base end portion of the heel portion, the appearance of the heel portion is not significantly changed. Moreover, when providing a built-up part in the rear surface of the base end part of a collar part, a shaft cylinder front end and a collar part rear surface can contact | abut appropriately.

According to the sixth aspect, the strength against bending deformation of the collar portion is further improved, and the occurrence of the whitening phenomenon is suppressed.

According to the seventh aspect, the collar portion is sufficiently reinforced, and the occurrence of the whitening phenomenon can be sufficiently suppressed. Furthermore, when the built-up portion is provided on the front surface of the base end portion of the heel portion, the appearance of the heel portion is not significantly changed. Moreover, when providing a built-up part in the rear surface of the base end part of a collar part, a shaft cylinder front end and a collar part rear surface can contact | abut appropriately.

The best mode for carrying out the present invention will be described.

[1] In the first embodiment of the present invention, the ink that temporarily holds the overflowing ink accompanying the pressure increase in the ink tank 5 between the ink tank 5 that directly stores the ink and the pen tip 2 is used. A reservoir member 3 is provided, and the ink reservoir member 3 includes an ink reservoir 35 that temporarily holds the overflow ink, and a straight tubular shaft center portion 31 that projects forward of the ink reservoir 35. , A synthetic resin member integrally formed with a flange 32 protruding radially outward from the outer peripheral surface of the shaft center portion 31, the ink tank 5 is provided in the shaft tube 4, and the shaft tube 4 The ink reservoir 35 of the ink reservoir member 3 is fitted into the front end opening of the first cylinder, and the collar 32 is brought into contact with the front end of the shaft cylinder 4 and exposed to the outside from the front end of the shaft cylinder 4. The ink storage member 3 is made of a transparent synthetic resin. The base end portion of the front and rear surfaces to NikuSakari portion 34A of the flange portion 32, that is provided 34B (claim 1) and the requirements.

  The direct liquid writing instrument 1 (Claim 1) is provided with the built-up portions 34A and 34B on the front surface of the proximal end portion of the collar portion 32 and the rear surface of the proximal end portion of the collar portion 32. When the base end portion is reinforced and the flange portion 32 comes into contact with the front end of the shaft tube 4, the bending deformation of the flange portion 32 can be suppressed, and the occurrence of the whitening phenomenon at the base end portion of the flange portion 32 can be avoided. As a result, the appearance of the front portion of the transparent ink retaining member 3 exposed to the outside is not impaired.

[2] In the second embodiment of the present invention, the ink that temporarily holds the overflow ink due to the pressure increase in the ink tank 5 between the ink tank 5 that directly stores the ink and the pen tip 2 is used. A reservoir member 3 is provided, and the ink reservoir member 3 includes an ink reservoir 35 that temporarily holds the overflow ink, and a straight tubular shaft center portion 31 that projects forward of the ink reservoir 35. , A synthetic resin member integrally formed with a flange 32 protruding radially outward from the outer peripheral surface of the shaft center portion 31, the ink tank 5 is provided in the shaft tube 4, and the shaft tube 4 The ink reservoir 35 of the ink reservoir member 3 is fitted into the front end opening of the first cylinder, and the collar 32 is brought into contact with the front end of the shaft cylinder 4 and exposed to the outside from the front end of the shaft cylinder 4. The ink storage member 3 is made of a transparent synthetic resin. Providing the NikuSakari portion 34B on the rear surface of the base end portion of the flange portion 32 and (claim 2) the requirements.

  In the direct liquid writing instrument 1 (Claim 2), the base end portion of the collar portion 32 is reinforced by providing the build-up portion 34B on at least the rear surface of the base end portion of the collar portion 32, and the collar portion 32 is pivoted. When contacting the front end of the cylinder 4, it is possible to suppress the bending deformation of the flange portion 32 and to avoid the occurrence of a whitening phenomenon at the proximal end portion of the flange portion 32. As a result, the appearance of the front portion of the transparent ink retaining member 3 exposed to the outside is not impaired.

[3] In the third embodiment of the present invention, the ink that temporarily holds the overflow ink due to the pressure increase in the ink tank 5 between the ink tank 5 that directly stores the ink and the pen tip 2 is used. A reservoir member 3 is provided, and the ink reservoir member 3 includes an ink reservoir 35 that temporarily holds the overflow ink, and a straight tubular shaft center portion 31 that projects forward of the ink reservoir 35. , A synthetic resin member integrally formed with a flange 32 protruding radially outward from the outer peripheral surface of the shaft center portion 31, the ink tank 5 is provided in the shaft tube 4, and the shaft tube 4 The ink reservoir 35 of the ink reservoir member 3 is fitted into the front end opening of the first cylinder, and the collar 32 is brought into contact with the front end of the shaft cylinder 4 and exposed to the outside from the front end of the shaft cylinder 4. The ink storage member 3 is made of a transparent synthetic resin. Providing the NikuSakari portion 34A on the front of the base end portion of the flange portion 32 and (claim 3) requirements.

  The direct liquid writing instrument 1 (Claim 3) is provided with a built-up portion 34A on at least the front surface of the proximal end portion of the collar portion 32, whereby the proximal end portion of the collar portion 32 is reinforced, and the collar portion 32 is pivoted. When contacting the front end of the cylinder 4, it is possible to suppress the bending deformation of the flange portion 32 and to avoid the occurrence of a whitening phenomenon at the proximal end portion of the flange portion 32. As a result, the appearance of the front portion of the transparent ink retaining member 3 exposed to the outside is not impaired.

  In the direct liquid writing instrument 1 (Claim 1, Claim 2, Claim 3), transparent means colorless and transparent (non-colored transparent), translucent, or colored transparent (colored transparent).

  In the present invention (Claim 1, Claim 2 and Claim 3), the built-up portions 34A and 34B are connected to the flange portion 32 of the ink retaining member 3 and the outer peripheral surface of the straight tubular shaft portion 31. It is integrally formed at the boundary portion. The build-up portions 34A and 34B include, for example, a configuration that is formed in an annular shape that is continuous in a circumferential shape, or a configuration that includes a plurality of axially extending ribs that are distributed in a circumferential shape.

[4] In the direct liquid writing instrument 1 (Claims 1, 2, and 3), the build-up portions 34A and 34B are formed in an annular shape on the outer peripheral surface of the shaft center portion 31, and the longitudinal section has a C-chamfered shape. It is preferable that it is present (claim 4). Thereby, compared with the case of the rib, the strength against bending deformation of the flange portion 32 is further improved, and the occurrence of the whitening phenomenon is suppressed.

[5] In the fourth aspect, it is preferable that the C chamfer dimension of the built-up portions 34A and 34B is 0.3 mm to 1.0 mm (Claim 5). Thereby, sufficient reinforcement | strengthening of the collar part 32 is made | formed and generation | occurrence | production of the whitening phenomenon can fully be suppressed. Furthermore, in the range of the C chamfer dimension, in the case of the built-up portion 34A formed on the front surface of the base end portion of the flange portion 32, the appearance of the flange portion 32 is not greatly changed. Further, in the range of the C chamfer dimension, in the case of the built-up portion 34B formed on the rear surface of the base end portion of the flange portion 32, the front end of the shaft cylinder 4 and the rear surface of the flange portion 32 can properly come into contact.

  If the C chamfer dimension of the build-up portions 34A and 34B is less than 0.3 mm, there is a possibility that sufficient reinforcement of the flange portion 32 cannot be achieved.

  If the C chamfer dimension of the build-up portion 34A exceeds 1.0 mm, the appearance of the build-up portion 32 may be greatly changed in the case of the build-up portion 34A formed on the front surface of the base end portion of the fillet portion 32. . Further, in the case of the built-up portion 34B formed on the rear surface of the base end portion of the collar portion 32, when the C chamfer dimension of the built-up portion 34B exceeds 1.0 mm, the ink retaining member 3 is moved to the shaft cylinder 4. When the front end opening is inserted, the built-up portion 34B comes into contact with the front end of the shaft cylinder 4, the contact state with the front end of the shaft cylinder 4 becomes unstable, and the front and rear of the ink reservoir member 3 in the front end opening of the shaft cylinder 4 Setting the position of the direction may be difficult.

[6] In the direct liquid writing instrument 1 (Claims 1, 2, and 3), the build-up portions 34A and 34B are formed in an annular shape on the outer peripheral surface of the shaft portion 31, and the longitudinal section has an R chamfer shape. It is preferable that it is present (claim 6). Thereby, compared with the case of the rib, the strength against bending deformation of the flange portion 32 is further improved, and the occurrence of the whitening phenomenon is suppressed.

[7] In the direct liquid writing instrument 1 (Claim 6), it is preferable that the R chamfering dimensions of the built-up portions 34A and 34B are 0.3 mm to 1.0 mm (Claim 7). Thereby, sufficient reinforcement | strengthening of the collar part 32 is made | formed and generation | occurrence | production of the whitening phenomenon can fully be suppressed. Further, in the range of the R chamfer dimension, in the case of the built-up portion 34A formed on the front surface of the base end portion of the flange portion 32, the appearance of the flange portion 32 is not greatly changed. Further, in the range of the R chamfer dimension, in the case of the built-up portion 34 </ b> B formed on the rear surface of the base end portion of the flange portion 32, the front end of the shaft tube 4 and the rear surface of the flange portion 32 can appropriately come into contact.

  If the R chamfer dimension of the built-up portions 34A and 34B is less than 0.3 mm, there is a possibility that sufficient reinforcement of the flange portion 32 cannot be achieved.

  If the R chamfer dimension of the built-up portion 34A exceeds 1.0 mm, the appearance of the built-up portion 32 may be greatly changed in the case of the built-up portion 34A formed on the front surface of the base end portion of the raised portion 32. There is. Further, in the case of the built-up portion 34B formed on the rear surface of the base end portion of the collar portion 32, if the R chamfer dimension of the built-up portion 34B exceeds 1.0 mm, the ink storage member 3 is moved to the shaft cylinder 4. When the front end opening is inserted, the built-up portion 34B comes into contact with the front end of the shaft cylinder 4, the contact state with the front end of the shaft cylinder 4 becomes unstable, and the front and rear of the ink reservoir member 3 in the front end opening of the shaft cylinder 4 Setting the position of the direction may be difficult.

[First embodiment]
1 and 2 show a first embodiment of the present invention.
The direct liquid writing instrument 1 of this embodiment includes an ink reservoir member 3 having a pen tip 2 at the front end, and a shaft cylinder 4 into which the ink reservoir member 3 is inserted.

-Shaft cylinder The said shaft cylinder 4 is a bottomed cylindrical body obtained from the injection molding of a synthetic resin. The front end of the shaft cylinder 4 is opened and the rear end is closed. When the ink reservoir member 3 is inserted into the front end opening of the shaft cylinder 4, an ink tank 5 is formed inside the shaft cylinder 4 behind the ink reservoir member 3. Ink is stored directly in the ink tank 5.

Ink reservoir member The ink reservoir member 3 is obtained by injection molding of a transparent synthetic resin (for example, ABS resin). The ink storage member 3 includes a straight tubular shaft center portion 31, a plurality of comb teeth portions 33 integrally formed on the outer peripheral surface of the shaft center portion 31, and a shaft center portion in front of the comb teeth portion 33. 31 and a flange 32 formed integrally with the outer peripheral surface of 31. The comb tooth portion 33 forms an ink reservoir portion 35 including a plurality of comb grooves. The ink reservoir 35 is a portion that temporarily holds the overflow ink from the ink tank 5, and is fitted into the front end opening of the shaft cylinder 4.

The collar portion The collar portion 32 is integrally formed in an annular shape (disc shape) on the outer peripheral surface of the shaft center portion 31. An air groove 36 is provided in the axial direction on the outer peripheral surface of the flange portion 32 so as to allow communication between the inside of the shaft cylinder 4 and the outside air. After the ink reservoir 35 of the ink reservoir 3 is inserted into the front end opening of the shaft cylinder 4, the rear surface of the collar 32 is brought into contact with the front end of the shaft cylinder 4. The flange portion 32 is exposed to the outside from the front end of the shaft tube 4.

-Overlaying portion C-chamfered built-in portions 34A and 34B are integrated with the outer peripheral surface of the axial center portion 31 on the front surface of the proximal end portion of the flange portion 32 and the rear surface of the proximal end portion of the flange portion 32 It is formed. The C-chamfered built-up portion 34A on the front surface of the base end portion of the flange portion 32 has a C-chamfer dimension set to 0.5 mm. The C-chamfered built-up portion 34B on the rear surface of the base end portion of the flange portion 32 has a C-chamfer dimension set to 0.7 mm.

[Second Embodiment]
FIG. 3 shows a second embodiment of the present invention.
The direct liquid writing instrument 1 of the present embodiment is a modification of the first embodiment, and is different from the first embodiment in that the C-chamfered built-up portion 34B is formed only on the rear surface of the base end portion of the collar portion 32. It is a point provided.

  The build-up portion 34B is integrally formed in an annular shape on the outer peripheral surface of the shaft center portion 31 as in the first embodiment. The C chamfer dimension of the build-up portion 34B is set to 0.7 mm as in the first embodiment.

  Since the other configuration of this embodiment is the same as that of the first embodiment, description thereof is omitted.

[Third embodiment]
FIG. 4 shows a third embodiment of the present invention.
The direct liquid writing instrument 1 of the present embodiment is a modification of the first embodiment, and is different from the first embodiment in that the C-chamfered build-up portion 34A is provided only on the front surface of the base end portion of the collar portion 32. It is a point provided.

  The build-up portion 34A is integrally formed in an annular shape on the outer peripheral surface of the shaft center portion 31 as in the first embodiment. The C chamfer dimension of the built-up portion 34A is set to 0.5 mm as in the first embodiment.

  Since the other configuration of this embodiment is the same as that of the first embodiment, description thereof is omitted.

[Fourth embodiment]
5 and 6 show a fourth embodiment of the present invention.
The direct liquid writing instrument 1 according to this embodiment includes an ink reservoir member 3 having a nib 2 at the front end, and a shaft cylinder 4 into which the ink reservoir member 3 is inserted.

-Shaft cylinder The said shaft cylinder 4 is a bottomed cylindrical body obtained from the injection molding of a synthetic resin. The front end of the shaft cylinder 4 is opened and the rear end is closed. When the ink reservoir member 3 is inserted into the front end opening of the shaft cylinder 4, an ink tank 5 is formed inside the shaft cylinder 4 behind the ink reservoir member 3. Ink is stored directly in the ink tank 5.

Ink reservoir member The ink reservoir member 3 is obtained by injection molding of a transparent synthetic resin (for example, ABS resin). The ink storage member 3 includes a straight tubular shaft center portion 31, a plurality of comb teeth portions 33 integrally formed on the outer peripheral surface of the shaft center portion 31, and a shaft center portion in front of the comb teeth portion 33. 31 and a flange 32 formed integrally with the outer peripheral surface of 31. The comb tooth portion 33 forms an ink reservoir portion 35 including a plurality of comb grooves. The ink reservoir 35 is a portion that temporarily holds the overflow ink from the ink tank 5, and is fitted into the front end opening of the shaft cylinder 4.

The collar portion The collar portion 32 is integrally formed in an annular shape (disc shape) on the outer peripheral surface of the shaft center portion 31. In the outer peripheral surface of the flange portion 32, an air groove 36 is provided in the axial direction so as to allow communication between the inside of the shaft cylinder 4 and the outside air. After the ink reservoir 35 of the ink reservoir 3 is inserted into the front end opening of the shaft cylinder 4, the rear surface of the collar 32 is brought into contact with the front end of the shaft cylinder 4. The flange portion 32 is exposed to the outside from the front end of the shaft tube 4.

-Overlaying portion On the front surface of the base end portion of the flange portion 32 and the rear surface of the base end portion of the flange portion 32, the R-chamfered build-up portions 34A, 34B are integrally formed in an annular shape on the outer peripheral surface of the shaft portion 31. Is done. The R chamfering-shaped built-up portion 34A on the front surface of the base end portion of the collar portion 32 has an R chamfering dimension set to 0.5 mm. An R chamfered portion 34B on the rear surface of the base end portion of the flange portion 32 has an R chamfer dimension set to 0.7 mm.

[Fifth embodiment]
FIG. 7 shows a fifth embodiment of the present invention.
The direct liquid writing instrument 1 of the present embodiment is a modification of the fourth embodiment, and is different from the fourth embodiment in that an R-chamfered build-up portion 34B is formed only on the rear surface of the base end portion of the collar portion 32. It is a point provided.

  The build-up portion 34B is integrally formed in an annular shape on the outer peripheral surface of the shaft center portion 31 as in the fourth embodiment. The R chamfer dimension of the build-up portion 34B is set to 0.5 mm.

  In addition, since the other structure of a present Example is the same as that of 4th Example, description is abbreviate | omitted.

[Sixth embodiment]
FIG. 8 shows a sixth embodiment of the present invention.
The direct liquid writing instrument 1 of the present embodiment is a modification of the fourth embodiment. The difference from the fourth embodiment is that the R-chamfered build-up portion 34A is provided only on the front surface of the base end portion of the flange portion 32. It is a point provided.

  The build-up portion 34A is integrally formed in an annular shape on the outer peripheral surface of the shaft center portion 31 as in the fourth embodiment. The R chamfer dimension of the built-up portion 34A is set to 0.5 mm as in the fourth embodiment.

  In addition, since the other structure of a present Example is the same as that of 4th Example, description is abbreviate | omitted.

  In any of the direct liquid writing instruments 1 of the first to sixth embodiments, the ink reservoir 35 of the ink reservoir 3 is inserted into the front end opening of the shaft cylinder 4 and the rear surface of the collar 32 is pivoted. When brought into contact with the front end of the cylinder 4, no whitening phenomenon occurred at the base end portion of the flange portion 32. Therefore, the appearance of the front part of the ink retaining member 3 having transparency exposed to the outside was not impaired.

It is a longitudinal cross-sectional view of 1st Example of this invention. FIG. 2 is an enlarged vertical sectional view of an S part in FIG. 1. It is a principal part expanded longitudinal cross-sectional view of 2nd Example of this invention. It is a principal part expanded longitudinal cross-sectional view of 3rd Example of this invention. It is a longitudinal cross-sectional view of 4th Example of this invention. FIG. 6 is an enlarged vertical sectional view of a T portion in FIG. 5. It is a principal part expanded longitudinal cross-sectional view of 5th Example of this invention. It is a principal part expanded longitudinal cross-sectional view of 6th Example of this invention. It is a principal part expanded vertical sectional view explaining the conventional malfunction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Direct liquid type writing instrument 2 Nib tip 3 Ink storage member 31 Axial center part 32 collar part 33 Comb tooth part 34A Overlay part
34B Overlay part 35 Ink reservoir part 36 Air groove 4 Shaft cylinder 5 Ink tank

Claims (7)

An ink storage member is provided between the ink tank for storing ink directly and the pen tip to temporarily hold the overflow ink that accompanies an increase in pressure in the ink tank, and the ink storage member stores the overflow ink. Temporarily holding the ink reservoir, a straight tubular axial center projecting forward of the ink reservoir, and a flange projecting radially outward from the outer peripheral surface of the axial central A formed synthetic resin member, wherein the ink tank is provided in a shaft cylinder, an ink storage portion of the ink storage member is fitted into a front end opening of the shaft cylinder, and the collar portion is connected to the shaft cylinder. The ink storage member is made of a transparent synthetic resin and is exposed to the outside from the front end of the shaft tube, and is formed of a transparent synthetic resin. A direct liquid-type writing instrument characterized by having a built-up portion on the front and rear surfaces. An ink storage member is provided between the ink tank for storing ink directly and the pen tip to temporarily hold the overflow ink that accompanies an increase in pressure in the ink tank, and the ink storage member stores the overflow ink. Temporarily holding the ink reservoir, a straight tubular axial center projecting forward of the ink reservoir, and a flange projecting radially outward from the outer peripheral surface of the axial central A formed synthetic resin member, wherein the ink tank is provided in a shaft cylinder, an ink storage portion of the ink storage member is fitted into a front end opening of the shaft cylinder, and the collar portion is connected to the shaft cylinder. The ink storage member is made of a transparent synthetic resin and is exposed to the outside from the front end of the shaft tube, and is formed of a transparent synthetic resin. A direct liquid writing instrument, characterized in that a rear surface is provided with a built-up portion. An ink storage member is provided between the ink tank for storing ink directly and the pen tip to temporarily hold the overflow ink that accompanies an increase in pressure in the ink tank, and the ink storage member stores the overflow ink. Temporarily holding the ink reservoir, a straight tubular axial center projecting forward of the ink reservoir, and a flange projecting radially outward from the outer peripheral surface of the axial central A formed synthetic resin member, wherein the ink tank is provided in a shaft cylinder, an ink storage portion of the ink storage member is fitted into a front end opening of the shaft cylinder, and the collar portion is connected to the shaft cylinder. The ink storage member is made of a transparent synthetic resin and is exposed to the outside from the front end of the shaft tube, and is formed of a transparent synthetic resin. A direct liquid type writing instrument characterized by having a built-up part on the front. 4. The direct liquid writing instrument according to claim 1, wherein the build-up portion is formed in an annular shape on the outer peripheral surface of the shaft center portion and has a C-chamfered longitudinal section. The direct liquid writing instrument according to claim 4, wherein a C chamfer dimension of the overlay is 0.3 mm to 1.0 mm. 4. The direct liquid writing instrument according to claim 1, wherein the build-up portion is formed in an annular shape on the outer peripheral surface of the shaft center portion, and has a longitudinal cross-sectional shape of an R chamfer. The direct liquid writing instrument according to claim 6, wherein an R chamfer dimension of the build-up portion is 0.3 mm to 1.0 mm.

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