JP2015009455A - Thermochromic writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermochromic writing utensil comprising a pen nib capable of writing as the thermochromic writing utensil, a friction portion capable of heat-decoloring the trace of the writing by friction and an input portion that enables inputting into an electrostatic input device.SOLUTION: A friction portion 6b also serves as an input portion 6b having electroconductivity that operates an input screen with an input pen and fingers and performs inputting into an input device that detects a position of an operation portion of the input screen by an electrostatic capacitance system, where a friction coefficient when the friction portion 6b slidably contacts the input screen of the input device is set to be smaller than a friction coefficient when the friction portion 6b slidably contacting the paper surface.

Description

  The present invention relates to a thermochromic writing instrument. Specifically, a nib that can eject thermochromic ink, and a friction part that is made of a low-abrasion elastic material that can rub the handwriting of the thermochromic ink and thermally discolor the handwriting by frictional heat generated at that time. And a thermochromic writing instrument.

  Conventionally, there has been known a thermochromic writing instrument with a friction part that thermally discolors handwriting written on paper using a thermochromic ink with frictional heat when rubbing. For example, Patent Document 1 discloses reversible thermochromic. The structure with a friction body provided at the rear end of the writing instrument shaft and the top of the writing instrument cap is written, and the writing instrument with the thermochromic ink written on the writing instrument is provided on the writing instrument. A structure that is thermally discolored by a friction body is disclosed. This thermochromic writing instrument has very convenient properties, and it is actually commercialized that the handwriting written on paper with the writing instrument can be rubbed and discolored by the friction part provided on the writing instrument. And satisfied with a wide range of users.

  On the other hand, as described in Patent Document 2, thin touch panel type input devices that are used by hand are gaining popularity in the market, and the input screen of electrostatic input type input devices is touched with a fingertip. Or, as disclosed in Patent Document 3, an input pen made of conductive rubber is provided at the front, and the input screen of the input device is handled in the same way as paper, and a picture is displayed. There is a growing demand for input pens that can draw and write letters.

  By the way, in the market, an input unit is provided on one end side of the shaft cylinder and a pen tip such as a ballpoint pen is provided on the other end side, so that not only input to the input device but also writing on paper can be performed. There is a writing instrument with a double-headed structure. However, in such a structure, an input unit for inputting to the input device is provided exclusively on the opposite side of the pen tip for writing on paper, so it is considered to implement in the above-described thermochromic writing instrument. In this case, it is necessary to prepare a friction tool for rubbing the handwriting separately from the writing tool, which is inconvenient.

  In addition, in the thermochromic writing instrument described in Patent Document 4, a rubbing member (friction portion) for thermally discoloring thermochromic ink with frictional heat is formed of a conductive material, and a shaft for holding the rubbing member (friction portion). A structure in which a cylinder and a cap are also made of a conductive material, and an input is made to the input device by sliding the scrubbing member of the thermochromic writing instrument as an input portion with respect to the input screen of the electrostatic input type input device. Is disclosed. However, it is better to have a frictional resistance against the paper surface and to generate frictional heat (friction part) and to the input screen of the input device it is better to slide smoothly without frictional resistance. The relationship with the member (input unit) is not considered, and when used to rub against the paper surface, the rubbing member slips and friction heat is less likely to occur, When used for writing characters, there has been a problem that it is difficult to input because the rubbing member is caught on the input screen by frictional resistance.

JP 2004-148744 A JP 2011-81825 A Japanese Patent No. 4142276 JP 2012-162019 A

  The present invention includes a pen tip capable of writing as a thermochromic writing instrument, a friction portion capable of thermally discoloring the handwriting by friction, and an input portion capable of performing input to an electrostatic input device. Another object is to provide a thermochromic writing instrument.

The present invention
“1. A low nib that disposes a pen tip capable of ejecting thermochromic ink in front of the shaft body, rubs the handwriting of the thermochromic ink, and heat-discolors the handwriting with frictional heat generated at that time. A thermochromic writing instrument having a friction portion made of an elastic material, wherein the friction portion operates an input screen with an input pen or a finger, and detects a position of an operation portion of the input screen by a capacitance method. It also serves as an input unit having conductivity to input to the input device, and the friction coefficient when the input screen of the input device is slidably smaller than the friction coefficient when the friction portion is slidably contacted with the paper surface. Thermochromic writing instrument.
2. 2. The thermochromic writing instrument according to item 1, wherein the shaft body is made of a conductive material, and the friction portion is connected to the shaft body.
3. 2. The thermochromic writing instrument according to claim 1, wherein the shaft body is made of an insulating material, and a conductive member having conductivity connected to the friction portion is accommodated in the shaft body. .
4). 4. The thermochromic writing instrument as described in 3 above, wherein the conductive member is a writing body having a nib at the tip.
5. The thermochromic writing instrument as described in 4 above, wherein the cursive is a ballpoint pen refill containing a thermochromic ink on a metal shaft.
6). Protrusion is provided on the friction part, and the protrusion is used as an input part so as to be slidably contacted with an input device that is detected by a capacitance method. 6. The thermochromic writing instrument according to any one of 1 to 5 above, wherein friction resistance is reduced.
7). The thermochromic property according to any one of 1 to 6, wherein the friction part is formed of a conductive elastomer, and the protrusion is immersed when pressure is applied to the friction part during friction. Writing instrument. It is.

As the pen tip for discharging the thermochromic ink, a ballpoint pen tip or a porous pen body can be used. In this case, the average particle size of the thermochromic microcapsule particles to be contained in the thermochromic ink is 0.1. Those having a thickness of ˜5.0 μm, preferably 0.5-3 μm are suitable. When the average particle diameter exceeds 3.0 μm, the flowability from the capillary gap of the ballpoint pen tip or the marking pen chip decreases, and when the average particle diameter is less than 0.5 μm, it is difficult to show high color development.
The “average particle diameter” defined in the present invention is a value obtained by using a laser type particle size distribution analyzer LA-300 (volume basis) manufactured by Horiba, Ltd., and using the median diameter as the average particle diameter.

In addition, as the thermochromic ink, a general-purpose ink can be applied regardless of reversible and irreversible, and the color of the handwriting can be changed, the color of the handwriting can be changed, and the color can be erased and colored by heating the handwriting by frictional heat. Can be applied selectively.
In particular, the change in the handwriting can be stably expressed for a long time without causing a change in composition by encapsulating the thermochromic composition in a microcapsule.
The thermochromic composition encapsulated in the microcapsule pigment includes (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, from the viewpoints of repeated usability and temperature change accuracy. (C) A reversible thermochromic composition comprising a reaction medium that determines the temperature at which the two color reactions occur is preferred.

Specific examples of the microcapsule pigment encapsulating the reversible thermochromic composition include predetermined ones described in JP-B-51-44706, JP-B-51-44707, JP-B-1-29398, and the like. Before and after the temperature (discoloration point), the color changes in the temperature range above the high temperature side discoloration point, and the color develops in the temperature range below the low temperature side discoloration point. There is only one specific state, and the other state is maintained while the heat or cold required to develop the state is applied, but at room temperature if the heat or cold is no longer applied It is possible to apply a microcapsule pigment encapsulating a heat decoloring type reversible thermochromic composition having a characteristic (ΔH = 1 to 7 ° C.) having a relatively small hysteresis width that returns to the state shown in FIG.
Furthermore, relatively large hysteresis characteristics (ΔH = 8 to 50) described in Japanese Patent Publication No. 4-17154, Japanese Patent Application Laid-Open No. 7-179777, Japanese Patent Application Laid-Open No. 7-33997, Japanese Patent Application Laid-Open No. 8-39936, and the like. C.) can also be applied.

  Further, it exhibits a large hysteresis characteristic described in JP-A-2006-137886, JP-A-2006-188660, JP-A-2008-45062, JP-A-2008-280523, etc., that is, due to temperature change. The shape of the curve plotting the change in color density follows a very different path when the temperature is raised from the lower temperature side than the color change temperature range, and vice versa. The reversible heat has a color memory in a specific temperature range (substantially two-phase holding temperature range) when the color development state in the low temperature range below the complete color development temperature or in the high temperature range above the complete color erase temperature. It is also possible to use a microcapsule pigment in which a color changing composition is encapsulated.

  Specifically, as a reversible thermochromic composition having color memory, which is applied to the thermochromic writing instrument of the present invention, a complete color development temperature is a temperature that can be obtained only in a freezer room, a cold district or the like, that is, −50 to 0 ° C., preferably −40 to −5 ° C., more preferably −30 to −10 ° C., and a complete decolorization temperature obtained from a frictional heat generated by a friction body, a heating body such as a hair dryer, that is, 50 to 95 ° C, preferably 50 to 90 ° C, more preferably 60 to 80 ° C, and ΔH value of 40 to 100 ° C to maintain colors that are exhibited in the normal state (daily life temperature range) It can function effectively.

  In addition, the thermochromic ink is stored in a writing body such as a ballpoint pen refill and stored in the writing tool shaft rather than directly in the writing tool shaft. When it runs out, refill exchange is possible, and it is easy to realize a structure that does not leak ink.

  The elastic material constituting the friction part is preferably a synthetic resin (rubber or elastomer) having elasticity. For example, silicon resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene). Copolymer), fluorine resin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM), etc., and not made of highly wearable elastic material (eg, eraser), but friction It is composed of a low-abrasion elastic material that hardly generates wear debris.

  In addition, the friction part of the present invention is also used as an input part for inputting to an input device that detects the position of the operation part of the input screen by a capacitance method, and therefore, a conductive material in which carbon fiber or metal fiber is mixed in resin. It is preferable to form with resin, and in particular, by forming with a conductive elastomer in which conductive fibers are mixed in an elastomer resin having elasticity, a structure that easily generates frictional heat during friction is obtained.

Since the friction part is also used as the input part, frictional heat is likely to be generated due to the frictional resistance between the friction part and the paper surface when rubbing the paper surface, and the friction part is input when inputting to the input device. It is important to set the material and surface treatment of the friction part or the shape when the friction part comes into contact with the paper surface so that the screen slides smoothly. At least the friction coefficient when the friction part is in sliding contact with the paper surface Therefore, it is necessary to reduce the coefficient of friction when the friction portion is in sliding contact with the input screen of the input device as the input portion. In this case, the coefficient of friction needs to be set as appropriate so that necessary frictional heat is generated in consideration of the decoloring temperature, ΔH value, and the like of the reversible thermochromic composition used in the thermochromic ink. In addition, when the contact area between the friction part and the input screen is reduced by providing a protrusion on the friction part, the frictional resistance when performing the input by sliding the friction part on the input screen decreases, Furthermore, the input is smooth.
Furthermore, the friction part is formed of a conductive elastomer, and the protrusion is immersed in the friction part with the pressure at the time of friction, so that when the friction part is rubbed against the paper surface, the protrusion of the friction part. Can generate frictional heat without getting in the way. Therefore, the elastomer resin constituting the conductive elastomer is preferably a soft one in which the protrusion of the friction part is easy to immerse, and a material that can immerse the protrusion during friction may be appropriately set while considering the shape and size of the protrusion. .

When the shaft body is formed of a conductive material, the material is a metal material such as stainless steel, aluminum, brass, or iron, a conductive resin material such as polyacetylene, polypyrrole, polythiophene, or polyaniline, carbon fiber material, non-conductive material. Examples thereof include composite conductive resins obtained by adding a conductor mainly composed of an inorganic substance to a conductive resin to provide an electric / electronic function.
In the case where the shaft body is formed of an insulating material, examples of the material include polypropylene, polycarbonate, ABS resin and the like, which are referred to as conductive insulating materials having no or very low conductivity. In consideration of cost, productivity of the hollow cylindrical body, workability, etc., it is preferable to use a non-conductive material such as polypropylene, polycarbonate, ABS resin.
Moreover, when shape | molding writing bodies, such as a ball-point refill, with an electroconductive member, it is preferable to shape | mold with stainless steel so that it may be hard to corrode with the ink accommodated in the inside of a writing body.
When the shaft body is formed of an insulating material, it is necessary to cause a second capacitance change with respect to the user holding the shaft body with respect to the conductive member accommodated therein. It is necessary to mold in consideration of the outer diameter, the thickness, the distance from the internal conductive member, and the like.

  According to the present invention, it is provided with a nib that can be written as a thermochromic writing instrument, a friction part that can thermally discolor the handwriting by friction, and an input part that can input to an electrostatic input device. A thermochromic writing instrument was obtained.

FIG. 1 is an overall explanatory view of the thermochromic writing instrument of Example 1. FIG. FIG. 2 is a partially enlarged view of the thermochromic writing instrument of Example 1. FIG. 3 is a partial cross-sectional view of the thermochromic writing instrument of Example 1. FIG. 4 is a partial cross-sectional view showing a state in which a tail crown is attached to the rear end of the shaft cylinder. FIG. 5 is a diagram showing a state in which writing is performed with the thermochromic writing instrument of Example 1. FIG. 6 is a diagram showing a state where the thermochromic writing instrument of Example 1 is thermochromic. FIG. 7 is a diagram showing a state in which the thermochromic writing instrument of Example 1 is inputting to the capacitance type input device. FIG. 8 is an overall explanatory view of the thermochromic writing instrument of Example 2. FIG. 9 is a partially enlarged view of the thermochromic writing instrument of Example 2. FIG. 10 is a partial cross-sectional view of the thermochromic writing instrument of Example 2. FIG. 11 is a diagram showing a state where writing is performed with the thermochromic writing instrument of Example 2. FIG. 12 is a diagram showing a state where the thermochromic writing instrument of Example 2 is thermochromic. FIG. 13 is a diagram illustrating a state where an input is performed to the capacitance type input device with the thermochromic writing instrument of Example 2.

Next, specific examples of embodiments of the present invention (hereinafter referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples.
In addition, in order to make the explanation easy to understand, the same numbers are given to the same members and the same parts in the drawings. In the description of the present embodiment, the side with the pen tip is expressed as the front side, and the opposite side is expressed as the back side.

The first embodiment will be described with reference to FIGS.
1 is an overall explanatory view of a thermochromic writing instrument of Example 1, FIG. 2 is a partially enlarged view, and FIG. 3 is a partial cross-sectional view. In the thermochromic writing instrument 1 of Example 1, the shaft cylinder 2 is composed of a brass front shaft 3 and a rear shaft 4, and the rear shaft 4 is rotated with respect to the front shaft 3. The pen tip 5a of the ballpoint pen refill 5 accommodated in the shaft cylinder 2 can be made to appear and disappear from the opening 3a formed in the front, and the writing state and the carrying state can be used properly.
The nib 5 has a ball-point pen tip structure, and the inside of the ball-point pen refill 5 is an average including a thermochromic composition having a complete color development temperature of −20 ° C., a complete color erasing temperature of 64 ° C., and a ΔH value of 70 ° C. A thermochromic ink (not shown) in which a microcapsule pigment having a particle diameter of 3 μm is dispersed in an aqueous medium is accommodated.

  Further, an opening 4b and a male screw portion 4c are formed in the rear end portion 4a of the rear shaft 4. A friction body 6 formed of a conductive elastomer obtained by kneading carbon powder with a silicon thermoplastic elastomer having a Shore A hardness of 70 determined according to JIS-K6253: 2006 is inserted into the opening 4b. A small-diameter portion 6a to be inserted into the opening 4b of the rear shaft 4 is formed in front of the friction body 6, and a dome-shaped friction portion 6b is formed in the rear of the friction body 6 and the rear of the friction portion 6b. A protrusion 6c is provided at the end.

  Further, the thermochromic writing instrument 1 is configured such that the tail crown 7 can be screwed to the rear shaft 4, and the female screw portion 7 b formed on the inner surface of the front opening 7 a of the tail crown 7 and the male shaft of the rear shaft 4. The screw part 4c is screwed. In this embodiment, as shown in FIG. 4, the friction portion 6 b of the friction body 6 is elastically brought into contact with the inner surface 7 c of the tail crown 7 with the tail crown 7 screwed to the rear shaft 4. Therefore, when the thermochromic writing instrument 1 is carried, the screwed state between the tail crown 7 and the rear shaft 4 is difficult to loosen even if vibration is applied.

Next, the state of writing on the paper surface with the thermochromic writing instrument 1 of the present embodiment will be described with reference to FIG. As shown in the figure, the thermochromic writing instrument 1 was able to write the characters 110a on the paper 110 by ejecting the thermochromic ink from the nib 5a protruding from the opening 3a of the front shaft 3.
Next, with reference to FIG. 6, a state in which the handwriting by the thermochromic ink written on the paper surface is erased by thermal discoloration with the thermochromic writing instrument 1 of the present embodiment will be described. As shown in the figure, the thermochromic writing instrument 1 rubs the paper 110 with the frictional part 6b of the friction body 6 inserted on the rear shaft 4 so that the handwriting written with the thermochromic ink is generated by frictional heat. The characters 110a could be erased by erasing the color.

  Next, with reference to FIG. 7, a state in which the thermochromic writing instrument 1 according to the present embodiment is input to the capacitance type input device will be described. As shown in the figure, when the thermochromic writing instrument 1 slides the projection 6c formed on the friction body 6 attached to the rear shaft 4 in contact with the input screen 120a in the capacitance type input device 120. The capacitance was changed on the input screen 120a through the shaft 4 and the conductive friction body 6 held by the user, and the line 120b could be drawn on the screen of the image creation software.

The thermochromic writing instrument 1 of the present embodiment has a smaller friction coefficient when the friction part 6b slides on the input screen 120a of the input device 120 than the friction coefficient when the friction part 6b slides on the paper surface 110. When friction is made on the paper surface, frictional heat is likely to be generated between the friction part 6b and the paper surface 110, and when input is made to the input device 120, the friction part 6b (input part). Was able to slide smoothly on the input screen 120a.
Further, in this embodiment, since the protrusion 6c is provided on the friction part 6b of the friction body 6, when the friction part 6b is brought into contact with the input screen 120a and is slid, the protrusion 6c is slid with respect to the input screen 120a. By doing so, the contact area was reduced, the frictional resistance was reduced, and smooth input could be performed.
Further, in this embodiment, since the friction body 6 is formed of a conductive elastomer, the protrusion 6c pressed against the paper 110 is immersed when the friction is performed, and the protrusion 6c does not interfere with the friction. Was able to do.

The second embodiment will be described with reference to FIGS.
8 is an overall explanatory view of the thermochromic writing instrument of Example 2, FIG. 9 is a partially enlarged view, and FIG. 10 is a partial cross-sectional view. In the thermochromic writing instrument 10 of Example 2, the shaft cylinder 20 is constituted by a polycarbonate front shaft 30 and a rear shaft 40, and a ballpoint pen accommodated in the shaft cylinder 20 from an opening 30a formed in front of the front shaft 30. The nib 50a of the refill 50 is protruded.
The nib 50 has a ballpoint pen tip structure, and a thermochromic composition having a complete color development temperature of −20 ° C., a complete color erasing temperature of 64 ° C., and a ΔH value of 70 ° C. is contained inside the ballpoint pen refill 50 made of stainless steel. Ink leakage caused by containing thermochromic ink 200 in which microcapsule pigment with an average particle diameter of 3 μm is dispersed in an aqueous medium and containing grease-like follower 210 that moves forward as the ink is consumed. (See FIG. 10).

An opening 40b is formed in the rear end portion 40a of the rear shaft 40, and a female screw portion 40c is formed on the inner surface of the opening 40b. The opening 40b is fitted with a friction body 60 formed of a conductive elastomer obtained by kneading carbon powder with a silicon thermoplastic elastomer having a Shore A hardness of 70 determined according to JIS-K6253: 2006.
In this embodiment, a male screw portion 60a formed in front of the friction body 60 is screwed to the female screw portion 40c of the rear shaft 40, and the rear end 50b of the ballpoint pen refill 50 is brought into contact therewith.
A dome-shaped friction portion 60b is formed at the rear of the friction body 60, and a protrusion 60c is provided at the rear end of the friction portion 60b. A slit 60d is formed at the front of the friction body 60. As the thermochromic ink 200 is consumed, air can enter the ballpoint pen refill 5.
Further, the thermochromic writing instrument 10 is configured such that a cap 70 can be attached to the front shaft 30.

Next, with reference to FIG. 11, the state of writing on the paper surface with the thermochromic writing instrument 10 of the present embodiment will be described. As shown in the figure, the thermochromic writing instrument 10 was able to write the characters 110a on the paper 110 by ejecting thermochromic ink from the nib 50a protruding from the opening 30a of the front shaft 30.
Next, with reference to FIG. 12, a state in which the handwriting with the thermochromic ink written on the paper surface is erased by thermal discoloration with the thermochromic writing instrument 10 of the present embodiment will be described. As shown in the figure, the thermochromic writing instrument 10 rubs the paper 110 with a dome-shaped friction portion 60b of a friction body 60 screwed to the rear shaft 40, thereby writing a handwriting written with the thermochromic ink. The characters 110a could be erased by erasing with frictional heat.

  Next, a state in which the thermochromic writing instrument 10 of this embodiment is input to a capacitance type input device will be described with reference to FIG. As shown in the figure, when the thermochromic writing instrument 10 slides the projection 60 c formed on the friction body 60 screwed to the rear shaft 40 in contact with the input screen 120 a in the capacitance type input device 120. The first electrostatic capacitance change is caused between the friction body 60 and the input screen 120a using the friction body 60 as an input unit, and the user's handle and the stainless steel ballpoint pen refill 50 (see FIG. 10). A second capacitance change was generated between them, and a line 120b could be drawn on the screen of the image creation software.

The thermochromic writing instrument 10 of this embodiment has a smaller friction coefficient when the friction part 60b slides on the input screen 120a of the input device 120 than the friction coefficient when the friction part 60b slides on the paper surface 110. When the paper surface is rubbed, frictional heat is likely to be generated between the frictional portion 60b and the paper surface 110, and when input is made to the input device 120, the frictional portion 60b (input portion). Was able to slide smoothly on the input screen 120a.
Further, in this embodiment, since the protrusion 60c is provided on the friction part 60b of the friction body 60, when the friction part 60b is slid while being brought into contact with the input screen 120a, the protrusion 60c is slid with respect to the input screen 120a. By doing so, the contact area was reduced, the frictional resistance was reduced, and smooth input could be performed.

  In this embodiment, since the friction body 60 is made of a conductive elastomer, the protrusion 60c pressed against the paper 110 is immersed when the friction is performed, and the protrusion 60c does not interfere with the friction. Could be done. Further, since the rear end of the ballpoint pen refill 50 is brought into contact with the friction body 60 that is screwed to prevent the ballpoint refill 50 from being positioned, the length of the ballpoint pen refill 50 varies due to the elastic deformation of the friction body 60. Can be absorbed. Furthermore, since the elastic friction body 60 receives the writing pressure when the pen tip 50a is applied with the writing pressure, the friction body 60 is deformed when an excessive writing pressure is applied. Thus, damage to the pen tip 50a can be prevented.

1,10 ... thermochromic writing instrument,
2,20 ... shaft tube,
3, 30 ... front shaft, 3a, 30a ... opening,
4, 40 ... rear axle, 4a, 40a ... rear end, 4b, 40b ... opening,
4c, 40c ... male screw part,
5, 50 ... Ballpoint pen refill, 5a, 50a ... Nib,
50b ... rear end,
6, 60 ... friction body, 6a ... small diameter part, 60a ... male screw part,
6b, 60b ... friction part, 6c, 60c ... projection,
60d ... slit,
7 ... Tail crown, 7a ... Front opening, 7b ... Female screw, 7c ... Inner surface,
70 ... Cap,
110 ... paper, 110a ... characters,
120 ... Capacitive input device, 120a ... Input screen,
120b ... a line drawn on the screen of the image creation software,
200 ... thermochromic ink, 210 ... grease.

Claims (7)

A low-abrasion elastic material in which a pen tip capable of ejecting thermochromic ink is disposed in front of the shaft body, and the handwriting of the thermochromic ink is rubbed and the handwriting is thermally discolored by frictional heat generated at that time. A thermochromic writing instrument having a friction portion comprising: an input device in which the friction portion operates an input screen with an input pen or a finger, and detects a position of an operation portion of the input screen by a capacitance method. Thermal discoloration characterized in that the friction coefficient when sliding the input screen of the input device is smaller than the friction coefficient when the friction portion is in sliding contact with the paper surface. Writing instrument. The thermochromic writing instrument according to claim 1, wherein the shaft body is made of a conductive material, and the friction portion is connected to the shaft body. 2. The thermochromic writing instrument according to claim 1, wherein the shaft body is made of an insulating material, and a conductive member having conductivity connected to the friction portion is accommodated in the shaft body. . The thermochromic writing instrument according to claim 3, wherein the conductive member is a writing body having a pen tip at a tip. The thermochromic writing instrument according to claim 4, wherein the writing body is a ballpoint pen refill containing a thermochromic ink on a metal shaft. Protrusion is provided on the friction part, and the protrusion is used as an input part so as to be slidably contacted with an input device that is detected by a capacitance method. The thermochromic writing instrument according to any one of claims 1 to 5, wherein frictional resistance is reduced. The thermochromic writing instrument according to claim 6, wherein the friction part is formed of a conductive elastomer, and the protrusion is immersed when pressure is applied to the friction part during friction.

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