Friction tool and thermochromic writing instrument

Abstract

To provide a friction tool and a thermochromic writing utensil which can prevent a friction part from wobbling during friction and enable stable friction work.SOLUTION: There are provided a friction tool 1 and a thermochromic writing utensil 11, in which the friction tool 1 has a friction part 4 at an end of a body 2. The friction part 4 is made of an elastic material and frictions handwriting of thermochromic ink so that the handwriting is thermally discolored by the frictional heat generated at that time. A support wall 3 for supporting one side of side surfaces of the friction part 4 is disposed at the end of the body 2. The side opposite to the support wall 3 of the side surface of the friction part 4 is exposed. The support wall 3 is formed so as to surround a certain range of one side of the side surfaces of the friction part 4. An upper end of the friction part 4 protrudes upward from an upper end of the support wall 3. The side surface of the friction part 4 has a circular cross-sectional shape, and the friction part 4 and the support wall 3 can be relatively rotated.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a friction tool and a thermochromic writing instrument. Specifically, the present invention relates to a friction tool and a thermochromic writing instrument provided with a friction portion made of an elastic material at an end of a main body, which rubs a trace of thermochromic ink and thermochromically changes the trace due to frictional heat generated during the rubbing.

Background Art

[0002] Conventionally, there has been known a writing instrument provided with an erasing member made of an elastic material that can erase a trace of thermochromic ink by frictional heat generated during rubbing, and the erasing member is attached to an end of a writing instrument main body or an end of a cap. (For example, Patent Document 1)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional writing instrument, the erasing portion of the erasing member (corresponding to the friction portion in the present application) protrudes axially outward from the end of the writing instrument main body or the end of the cap. Therefore, when the erasing member is pressed against the paper surface to rub the trace, the erasing portion of the erasing member may wobble due to bending deformation, and there is a risk that stable rubbing cannot be performed. In particular, when the writing instrument main body or the cap is tilted greatly from a perpendicular state with respect to the paper surface and the erasing member is used, or when the hardness of the elastic material of the erasing member is relatively low, the above problem is likely to occur.

[0005] The present invention aims to solve the above conventional problems, and provides a friction tool and a thermochromic writing instrument that can prevent the friction portion from wobbling during friction and enable stable friction work. In the present invention, "upper" refers to the friction portion side (upper side in the drawing), and "lower" refers to the opposite side.

Means for Solving the Problem

[0006] The first invention of the present application is a friction tool provided with a friction part made of an elastic material at an end of a main body, which rubs the handwriting of thermochromic ink and thermochromically changes the handwriting by the frictional heat generated at that time, wherein a support wall part for supporting one side of the side surface of the friction part is provided at the end of the main body, and it is required that the side opposite to the support wall part of the side surface of the friction part is exposed.

[0007] The friction tool of the first invention is provided with a support wall part for supporting one side of the side surface of the friction part at the end of the main body, and the side opposite to the support wall part of the side surface of the friction part is exposed (that is, the side opposite to the support wall part on the outer peripheral surface of the friction part) is exposed. As a result, during friction, the inner side in the radial direction of the support wall part and the outer side in the radial direction of the friction part (that is, the side surface of the friction part) come into contact, suppressing the bending deformation of the friction part and preventing the friction part from wobbling, enabling a stable friction operation. In particular, even when the friction tool is used with the main body greatly inclined from a perpendicular state to the paper surface, or when the hardness of the elastic material constituting the friction part is relatively low, it is possible to prevent the friction part from wobbling with respect to the main body during friction, enabling a stable friction operation. Note that the support wall part may be configured to be provided by attaching a separate member (for example, a support) to the end of the main body, or may be integrally formed with the end of the main body.

[0008] The second invention of the present application requires that, in the friction tool of the first invention, the support wall part is formed so as to surround a certain range on one side of the side surface of the friction part.

[0009] The friction tool of the second invention is formed such that the support wall part surrounds a certain range on one side of the side surface of the friction part. When the friction part is pressed against the paper surface with the inner side in the radial direction of the support wall part facing the paper surface during friction, the friction part is clamped between the paper surface and the support wall part, and the outer peripheral surface (that is, the side surface of the friction part) of the friction part is supported in a surrounding manner by the inner side in the radial direction of the support wall part, reliably preventing the friction part from wobbling.

[0010] The third invention of the present application requires that in the friction member of the first invention or the second invention, the upper end of the friction portion protrudes above the upper end of the support wall portion.

[0011] In the friction member of the third invention, since the upper end of the friction portion protrudes above the upper end of the support wall portion, a wide range from the upper end of the friction portion (i.e., the top of the friction portion) to the side surface of the friction portion (i.e., the side surface of the friction portion exposed on the side opposite to the support wall portion) can be brought into contact with the paper surface, and the contact between the paper surface and the friction portion becomes easy.

[0012] The fourth invention of the present application requires that in the friction member of any one of the first to third inventions, the side surface of the friction portion has a circular cross-sectional shape and the friction portion and the support wall portion are relatively rotatable.

[0013] In the friction member of the fourth invention, since the side surface of the friction portion has a circular cross-sectional shape and the friction portion and the support wall portion are relatively rotatable, a wide range of the outer surface of the friction portion can be used, and local wear of the friction portion can be suppressed.

[0014] The fifth invention of the present application requires that in the friction member of the fourth invention, the support wall portion includes a support body that is fixed or integrally formed, and the support body is rotatably attached to the end portion of the main body.

[0015] In the friction member of the fifth invention, since the support wall portion includes a support body that is fixed or integrally formed and the support body is rotatably attached to the end portion of the main body, a wide range of the outer surface of the friction portion can be used, local wear of the friction portion can be suppressed, and the support wall portion can be easily rotated with respect to the friction portion.

[0016] The sixth invention of the present application requires that in the friction member of the fourth invention, the support wall portion is integrally formed at the end portion of the main body, and the friction portion is rotatably attached to the main body.

[0017] In the friction tool of the sixth invention, since the support wall portion is integrally formed at the end portion of the main body and the friction portion is rotatably attached to the end portion of the main body, a wide range of the outer surface of the friction portion can be used, local wear of the friction portion can be suppressed, and the number of parts can be reduced to provide it at low cost.

[0018] The seventh invention of the present application is a thermochromic writing instrument including a shaft cylinder having a pen tip in which a thermochromic ink is incorporated and the thermochromic ink can be discharged, wherein the shaft cylinder is any one of the friction tools of the eleventh invention to the sixth invention.

[0019] In the thermochromic writing instrument of the seventh invention, during friction, the inner side in the radial direction of the support wall portion and the outer side in the radial direction of the friction portion come into contact with each other, preventing the friction portion from wobbling and enabling a stable friction operation.

[0020] The eighth invention of the present application is a thermochromic writing instrument including a shaft cylinder having a pen tip in which a thermochromic ink is incorporated and the thermochromic ink can be discharged, and a cap detachably attached to the pen tip side of the shaft cylinder, wherein the cap is a friction tool described in any one of the first invention to the sixth invention.

[0021] In the thermochromic writing instrument of the eighth invention, during friction, the inner side in the radial direction of the support wall portion and the outer side in the radial direction of the friction portion come into contact with each other, preventing the friction portion from wobbling and enabling a stable friction operation.

Advantages of the Invention

[0022] The friction tool of the present invention can prevent the friction portion from wobbling during friction, enabling a stable friction operation.

[0023] The thermochromic writing instrument of the present invention can prevent the friction portion from wobbling during friction, enabling a stable friction operation.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0025] <First Embodiment>

[0026] The friction member 1 and the thermochromic writing instrument 11 of the first embodiment of the present invention are shown in FIGS. 1 to 5. The friction member 1 and the thermochromic writing instrument 11 of the present embodiment include a main body 2, a friction portion 4 provided at the upper end portion of the main body 2, and a support 5 having a support wall portion 3.

[0027] ·Main body The main body 2 is a cylindrical body (for example, a cylindrical body) or a columnar body (for example, a columnar body). The material constituting the main body 2 is a harder material than the friction portion 4, and examples thereof include synthetic resins (for example, polycarbonate, polypropylene, etc.), metals, and woods.

[0028] On the outer peripheral surface of the upper end portion of the main body 2, a small-diameter cylindrical portion 21 and a large-diameter cylindrical portion 22 that are integrally connected rearward of the small-diameter cylindrical portion 21 and have an outer diameter larger than that of the small-diameter cylindrical portion 21 are provided. An upward step portion 23 is formed between the small-diameter cylindrical portion 21 and the large-diameter cylindrical portion 22. An engaged portion 22a (for example, an annular recess or an annular protrusion) is formed on the outer peripheral surface of the large-diameter cylindrical portion 22.

[0029] An attachment hole 24 that opens upward is formed in the upper end portion of the main body 2 (that is, inside the small-diameter cylindrical portion 21). An inward protrusion 24a is integrally formed on the inner surface of the attachment hole 24. The inward protrusion 24a is composed of an annular protrusion or a plurality of protrusions dispersed in a circumferential manner.

[0030] When the main body 2 is a cylindrical body with a hollow interior, it can constitute a shaft cylinder used in the thermochromic writing instrument 11 or a cap used in the thermochromic writing instrument 11. The shaft cylinder used in the thermochromic writing instrument 11 is a shaft cylinder in a thermochromic writing instrument provided with a pen tip capable of accommodating thermochromic ink inside and discharging the thermochromic ink. The cap used in the thermochromic writing instrument 11 is a cap attached to the pen tip side of the shaft cylinder in a thermochromic writing instrument provided with a pen tip capable of accommodating thermochromic ink inside and discharging the thermochromic ink.

[0031] ·Friction portion The friction portion 4 is formed of an elastic material. Examples include synthetic resins having elasticity (rubber, elastomer), such as silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene copolymer), polyester-based resin, olefin-based resin, ethylene propylene diene rubber (EPDM), etc. In this embodiment, the friction portion 4 is obtained by injection molding of a thermoplastic elastomer (for example, polyester-based elastomer, styrene-based elastomer).

[0032] The friction part 4 consists of a large-diameter part 41 and a small-diameter part 42 which is integrally connected to the rear of the large-diameter part 41 and has an outer diameter smaller than that of the large-diameter part 41. A stepped part 43 is formed between the large-diameter part 41 and the small-diameter part 42. An outward protrusion 42a is formed on the outer surface of the small-diameter part 42. The small-diameter part 42 is inserted into the mounting hole 24 at the upper end of the main body 2. The outward protrusion 42a of the small-diameter part 42 is engaged with the inward protrusion 24a on the inner surface of the mounting hole 24 of the main body 2 to prevent detachment. The large-diameter part 41 is exposed above the upper end of the main body 2. The upper end surface of the main body 2 abuts against the stepped part 43 between the large-diameter part 41 and the small-diameter part 42. The top 41a of the large-diameter part 41 of the friction part 4 is formed in a convex curved surface shape. The side surface 41b of the large-diameter part 41 of the friction part 4 is formed in a cylindrical shape. The friction part 4 (the large-diameter part 41 and the small-diameter part 42) has an outer surface with a circular cross-section. The friction part 4 is formed in a bottomed cylindrical shape with a closed upper end and an open lower end, but it may also be formed solidly.

[0033] · Support The support 5 is formed in a cylindrical shape with an inner hole penetrating in the axial direction and is obtained by a molded body of a synthetic resin (for example, a harder material than the friction part such as polycarbonate, polypropylene, polyacetal, etc.). The support 5 consists of a support wall part 3, a cylindrical upper part 51 integrally connected below the support wall part 3, and a cylindrical lower part 52 integrally connected below the upper part 51. A downward stepped part 53 is formed between the inner surface of the cylindrical upper part 51 and the inner surface of the cylindrical lower part 52.

[0034] The inner surface of the cylindrical upper part 51 and the outer surface of the small-diameter cylindrical part 21 at the upper end of the main body 2 are arranged to be slidable in the rotational direction. The inner surface of the cylindrical lower part 52 and the outer surface of the large-diameter cylindrical part 22 at the upper end of the main body 2 are arranged to be slidable in the rotational direction. The downward stepped part 53 on the inner surface of the support 5 and the upward stepped part 23 at the upper end of the main body 2 are slidably abutted in the rotational direction. Thereby, the inner peripheral surface of the support 5 and the outer peripheral surface at the upper end of the main body 2 are rotatably attached.

[0035] Further, an engaging portion 52a (e.g., an annular convex portion or an annular concave portion) is formed on the inner surface of the cylindrical lower portion 52. By engaging the engaging portion 52a on the inner surface of the support 5 with the engaged portion 22a on the outer surface of the main body 2, the support 5 and the main body 2 are rotationally engaged with each other in a non - removable manner.

[0036] ·Support wall portion The support wall portion 3 is composed of a plate - like piece that constitutes a part of the side wall of the cylindrical body. The cross - sectional shape of the support wall portion 3 is such that the inner surface is a concave curved surface and the outer surface is a convex curved surface. In the cross - section, the concave curved surface of the inner surface of the support wall portion 3 and the side surface 41b of the friction portion 4 have a substantially matching shape. Thereby, a certain range of the side surface 41b of the friction portion 4 is reliably surrounded by the support wall portion 3. The side surface 41b of the friction portion 4 on the side opposite to the support wall portion 3 is exposed.

[0037] The circumferential region of the friction portion 4 surrounded by the support wall portion 3 is preferably in the range of 20% to 50% of the entire circumference of the friction portion 4. If the circumferential region of the friction portion 4 surrounded by the support wall portion 3 is less than 20% of the entire circumference of the friction portion 4, there is a possibility that the wobbling of the friction portion 4 during friction cannot be reliably prevented. On the other hand, if the circumferential region of the friction portion 4 surrounded by the support wall portion 3 exceeds 50% of the entire circumference of the friction portion 4, there is a possibility that the support wall portion 3 contacts the paper surface during friction and damages the paper surface.

[0038] Alternatively, the support wall portion 3 may be a plurality of dispersed protrusions provided to surround the side surface of the friction portion 4. The upper end of the support wall portion 3 is located below the upper end of the friction portion 4 (the top portion 41a of the friction portion 4) and above the upper end of the main body 2. Also, the outer surface of the support 5 serves as a gripping portion during friction and can prevent the support 5 from rotating relative to the main body 2 during friction.

[0039] In the present invention, the attachment means between the friction portion 4 and the upper end portion of the main body 2 may also include, for example, a configuration in which the friction portion 4 is fixed to the upper end portion of the main body 2 by two-color molding, a configuration in which the friction portion 4 is fixed to the attachment hole 24 at the upper end portion of the main body 2 by press-fitting, screwing, or adhesion, etc., or a configuration in which the outer surface (the portion protruding upward) of the upper end portion of the main body 2 is fixed to the inner hole of the friction portion 4 by press-fitting, screwing, or adhesion, etc. Further, the friction portion 4 and the main body 2 may be integrally formed of the same elastic material.

[0040] ·During friction As shown in FIG. 4, during friction, when the friction portion 4 is pressed against the paper surface P in a state where the main body 2 is greatly inclined from a state perpendicular to the paper surface P (for example, the angle formed between the paper surface P and the axis of the main body 2 is 45 degrees or less), the inner surface of the support wall portion 3 and the outer surface of the friction portion 4 are pressed against each other. Thereby, the bending deformation of the friction portion 4 (that is, the bending deformation in the X1·X2 directions and the Y1·Y2 directions in FIG. 3) is suppressed, and a stable friction operation without wobbling of the friction portion 4 becomes possible.

[0041] The friction tool 1 and the thermochromic writing instrument 11 of the present embodiment are friction tools provided with a friction portion 4 made of an elastic material that rubs the handwriting of thermochromic ink and thermally changes the color of the handwriting due to the frictional heat generated at that time at the end portion of the main body 2. The end portion of the main body 2 is provided with a support wall portion 3 that supports one side of the side surface 41b of the friction portion 4. By exposing the side opposite to the support wall portion 3 of the side surface 41b of the friction portion 4, during friction, the radially inner side of the support wall portion 3 and the radially outer side of the friction portion 4 (the side surface 41b of the friction portion 4) come into contact, suppressing the bending deformation of the friction portion 4 and preventing the friction portion 4 from wobbling, enabling a stable friction operation. In particular, even when the main body 2 is greatly inclined from a state perpendicular to the paper surface P to use the friction tool, or when the hardness of the elastic material constituting the friction portion 4 is relatively low, it is possible to prevent the friction portion 4 from wobbling with respect to the main body 2 during friction, enabling a stable friction operation.

[0042] In the friction tool 1 and the thermochromic writing instrument 11 of this embodiment, since the support wall portion 3 is formed so as to surround a certain range on one side of the side surface 41b of the friction portion 4, when the friction portion 4 is pressed against the paper surface P with the inner side in the radial direction of the support wall portion 3 facing the paper surface P during friction, the friction portion 4 is clamped between the paper surface P and the support wall portion 3, the outer peripheral surface of the friction portion 4 is supported in a surrounding manner by the inner side in the radial direction of the support wall portion 3, and the wobbling of the friction portion 4 is reliably prevented.

[0043] In the friction tool 1 and the thermochromic writing instrument 11 of this embodiment, since the upper end of the friction portion 4 protrudes above the upper end of the support wall portion 3, a wide range from the upper end of the friction portion 4 (the top portion 41a of the friction portion 4) to the side surface 41b of the friction portion 4 can be brought into contact with the paper surface P, and the contact between the paper surface P and the friction portion 4 becomes easy.

[0044] In the friction tool 1 and the thermochromic writing instrument 11 of this embodiment, since the side surface 41b of the friction portion 4 has a circular cross-sectional shape and the friction portion 4 and the support wall portion 3 are relatively rotatable, a wide range of the outer surface of the friction portion 4 can be used, and local wear of the friction portion 4 can be suppressed.

[0045] In the friction tool 1 and the thermochromic writing instrument 11 of this embodiment, the support wall portion 3 includes a support body 5 that is fixed or integrally formed, and since the support body 5 is rotatably attached to the end portion of the main body 2, a wide range of the outer surface of the friction portion 4 can be used, local wear of the friction portion 4 can be suppressed, and the support wall portion 3 can be easily rotated with respect to the friction portion 4.

[0046] <Second Embodiment> The friction tool 1 and the thermochromic writing instrument 11 according to the second embodiment of the present invention are shown in FIGS. 6 to 10. The friction tool 1 and the thermochromic writing instrument 11 of this embodiment include a main body 2 having a support wall portion 3 and a friction portion 4 provided at the upper end portion of the main body 2.

[0047] · Main body The main body 2 is a cylindrical body (e.g., a circular cylindrical body) or a columnar body (e.g., a circular columnar body). Examples of the material constituting the main body 2 include hard materials compared to the friction part 4, such as synthetic resins (e.g., polycarbonate, polypropylene, etc.), metals, wood, and the like.

[0048] An attachment hole 24 that opens upward is formed at the upper end of the main body 2. An inward protrusion 24a is integrally formed on the inner surface of the attachment hole 24. The inward protrusion 24a is composed of an annular protrusion or a plurality of protrusions dispersed circumferentially.

[0049] When the main body 2 is a cylindrical body with a hollow interior, it can constitute a shaft cylinder used in the thermochromic writing instrument 11 or a cap used in the thermochromic writing instrument 11. The shaft cylinder used in the thermochromic writing instrument 11 is a shaft cylinder in a thermochromic writing instrument having a pen tip with a thermochromic ink accommodated therein and capable of discharging the thermochromic ink. The cap used in the thermochromic writing instrument 11 is a cap attached to the pen tip side of the shaft cylinder in a thermochromic writing instrument having a pen tip with a thermochromic ink accommodated therein and capable of discharging the thermochromic ink.

[0050] ·Friction part The friction part 4 is formed of an elastic material. Examples include synthetic resins having elasticity (rubber, elastomer), such as silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene copolymer), polyester-based resin, olefin-based resin, ethylene propylene diene rubber (EPDM), and the like. In the present embodiment, the friction part 4 is obtained by injection molding of a thermoplastic elastomer (e.g., polyester-based elastomer, styrene-based elastomer).

[0051] The friction part 4 is composed of a large-diameter part 41 and a small-diameter part 42 that is integrally connected to the rear of the large-diameter part 41 and has an outer diameter smaller than that of the large-diameter part 41. A stepped part 43 is formed between the large-diameter part 41 and the small-diameter part 42. An outward protrusion 42a is formed on the outer surface of the small-diameter part 42. The small-diameter part 42 is inserted into the mounting hole 24 at the upper end of the main body 2. The outward protrusion 42a of the small-diameter part 42 is engaged with the inward protrusion 24a on the inner surface of the mounting hole 24 of the main body 2 to prevent it from coming off. The friction part 4 is rotatably mounted in the mounting hole 24 of the main body 2. The large-diameter part 41 is exposed above the upper end of the main body 2. The upper end surface of the main body 2 abuts against the stepped part 43 between the large-diameter part 41 and the small-diameter part 42. The top 41a of the large-diameter part 41 of the friction part 4 is formed in a convex curved surface shape. The side surface 41b of the large-diameter part 41 of the friction part 4 is formed in a cylindrical shape. The friction part 4 (the large-diameter part 41 and the small-diameter part 42) has an outer surface with a circular cross-section. The friction part 4 is formed in a bottomed cylindrical shape with a closed upper end and an open lower end, but it may also be formed solid.

[0052] · Support wall part The support wall part 3 is integrally formed at the upper end of the main body 2. The support wall part 3 is composed of a plate-like piece that constitutes a part of the side wall of a cylinder. The cross-sectional shape of the support wall part 3 is such that the inner surface is a concave curved surface and the outer surface is a convex curved surface. In the cross-section, the concave curved surface of the inner surface of the support wall part 3 and the side surface 41b of the friction part 4 have substantially the same shape. Thereby, a certain range of the side surface 41b of the friction part 4 is surely surrounded by the support wall part 3. The side surface 41b of the friction part 4 on the side opposite to the support wall part 3 is exposed.

[0053] The circumferential region of the friction part 4 surrounded by the support wall part 3 is preferably in the range of 20% to 50% of the entire circumference of the friction part 4. If the circumferential region of the friction part 4 surrounded by the support wall part 3 is less than 20% of the entire circumference of the friction part 4, there is a possibility that the wobbling of the friction part 4 during friction cannot be surely prevented. On the other hand, if the circumferential region of the friction part 4 surrounded by the support wall part 3 exceeds 50% of the entire circumference of the friction part 4, there is a possibility that the support wall part 3 contacts the paper surface during friction and damages the paper surface.

[0054] The support wall portion 3 may alternatively be a plurality of dispersed protrusions provided so as to surround a certain range of the side surface 41b of the friction portion 4. The upper end of the support wall portion 3 is located below the upper end of the friction portion 4 (the top portion 41a of the friction portion 4) and above the upper end of the main body 2.

[0055] In the present invention, the attachment means between the friction portion 4 and the upper end portion of the main body 2 only needs to enable the friction portion 4 and the main body 2 to be rotatable. Examples of the configuration include one in which the friction portion 4 is inserted or screwed into the attachment hole 24 at the upper end portion of the main body 2, or one in which the outer surface (the portion protruding upward) of the upper end portion of the main body 2 is inserted or screwed into the inner hole of the friction portion 4.

[0056] ·During friction As shown in FIG. 9, during friction, when the friction portion 4 is pressed against the paper surface P with the main body 2 greatly inclined from a state perpendicular to the paper surface P (for example, the angle formed between the paper surface P and the axis of the main body 2 is 45 degrees or less), the inner surface of the support wall portion 3 and the outer surface of the friction portion 4 are brought into pressure contact. Thereby, the bending deformation of the friction portion 4 (i.e., the bending deformation in the X1·X2 directions and the Y1·Y2 directions in FIG. 8) is suppressed, and a stable friction operation without wobbling of the friction portion 4 becomes possible. During friction, since the side surface 41b of the large-diameter portion 41 of the friction portion 4 and the inner surface of the support wall portion 3 are strongly pressed against each other, the rotation of the friction portion 4 with respect to the main body 2 is also suppressed.

[0057] The friction tool 1 and the thermochromic writing instrument 11 of this embodiment are friction tools provided with a friction part 4 made of an elastic material at an end of a main body 2 that rubs the writing of the thermochromic ink and thermally changes the color of the writing due to the frictional heat generated during the rubbing. A support wall part 3 that supports one side of the side surface 41b of the friction part 4 is provided at the end of the main body 2, and the side opposite to the support wall part 3 of the side surface 41b of the friction part 4 is exposed. During friction, the inner side in the radial direction of the support wall part 3 and the outer side in the radial direction of the friction part 4 (the side surface 41b of the friction part 4) come into contact, suppressing the bending deformation of the friction part 4 and preventing the friction part 4 from wobbling, enabling a stable friction operation. In particular, even when the friction tool is used with the main body 2 greatly inclined from a perpendicular state with respect to the paper surface P, or even when the hardness of the elastic material constituting the friction part 4 is relatively low, it is possible to prevent the friction part 4 from wobbling with respect to the main body 2 during friction, enabling a stable friction operation.

[0058] In the friction tool 1 and the thermochromic writing instrument 11 of this embodiment, the support wall part 3 is formed so as to surround a certain range on one side of the side surface 41b of the friction part 4. When the friction part 4 is pressed against the paper surface P with the inner side in the radial direction of the support wall part 3 facing the paper surface P during friction, the friction part 4 is sandwiched between the paper surface P and the support wall part 3, and the outer peripheral surface of the friction part 4 is supported in a surrounding manner by the inner side in the radial direction of the support wall part 3, reliably preventing the wobbling of the friction part 4.

[0059] In the friction tool 1 and the thermochromic writing instrument 11 of this embodiment, the upper end of the friction part 4 protrudes above the upper end of the support wall part 3, enabling a wide range from the upper end of the friction part 4 (the top part 41a of the friction part 4) to the side surface 41b of the friction part 4 to come into contact with the paper surface P, facilitating the contact between the paper surface P and the friction part 4.

[0060] In the friction tool 1 and the thermochromic writing instrument 11 of this embodiment, the side surface 41b of the friction part 4 has a circular cross-sectional shape, and the friction part 4 and the support wall part 3 are relatively rotatable, enabling a wide range of the outer surface of the friction part 4 to be used and suppressing local wear of the friction part 4.

[0061] In the friction tool 1 and the thermochromic writing instrument 11 of this embodiment, since the support wall portion 3 is integrally formed with the main body 2 and the friction portion 4 is rotatably attached to the main body 2, a wide range of the outer surface of the friction portion 4 can be used, local wear of the friction portion 4 can be suppressed, and the number of parts can be reduced, enabling inexpensive provision.

Explanation of Signs

[0062] 1 Friction tool 11 Thermochromic writing instrument 2 Main body (shaft cylinder, cap) 21 Small-diameter cylinder portion 22 Large-diameter cylinder portion 22a Engaged portion 23 Upward step portion 24 Mounting hole 24a Inner protrusion 3 Support wall portion 4 Friction portion 41 Large-diameter portion 41a Top portion 41b Side surface 42 Small-diameter portion 42a Outer protrusion 43 Step portion 5 Support 51 Upper portion 52 Lower portion 52a Engaging portion 53 Downward step portion P Paper surface

Claims

1. A friction tool having a friction portion made of an elastic material at an end of a main body, which rubs the handwriting of a thermochromic ink and thermochromically changes the handwriting by frictional heat generated during the rubbing, wherein a support wall portion that supports one side of a side surface of the friction portion is provided at an end of the main body, the side of the side surface of the friction portion opposite to the support wall portion is exposed, the side surface of the friction portion has a circular cross-sectional shape, and the friction portion and the support wall portion are relatively rotatable characterized friction tool.

2. The friction tool according to claim 1, wherein an upper end of the friction portion protrudes above an upper end of the support wall portion.

3. The friction tool according to claim 1 or 2, further comprising a support body in which the support wall portion is fixed or integrally formed, and the support body is rotatably attached to an end of the main body.

4. An engaging portion is formed on an inner surface of the support body, an engaged portion is formed on an outer peripheral surface of the main body, and the support body and the main body are rotatably engaged with each other by engaging the engaging portion with the engaged portion. The friction tool according to claim 3.

5. The friction tool according to claim 1 or 2, wherein the support wall portion is integrally formed at an end of the main body, and the friction portion is rotatably attached to the end of the main body.

6. The friction tool according to claim 5, wherein an outward protrusion is formed on an outer surface of the friction portion, an inward protrusion is formed on an inner surface of the main body, and the outward protrusion is rotatably engaged with the inward protrusion to prevent detachment.

7. A thermochromic writing instrument comprising a shaft cylinder having a pen tip with a built-in thermochromic ink and capable of discharging the thermochromic ink, wherein the shaft cylinder is the friction tool according to any one of claims 1 to 6. Thermochromic writing instrument characterized by.

8. A thermochromic writing instrument comprising a shaft cylinder having a pen tip with a built-in thermochromic ink and capable of discharging the thermochromic ink, and a cap detachably attached to the pen tip side of the shaft cylinder, wherein the cap is the friction tool according to any one of claims 1 to 6. Thermochromic writing instrument characterized by.

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