JP2008296412A - Thermally allochroic writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermally-allochroic writing utensil capable of obtaining two kinds of handwriting by a thermally-allochroic ink by a single writing utensil. <P>SOLUTION: The pen tip 4A side of a first writing body 3A is arranged in one end opening of a cap 2 so as to be insertable therein, and the pen tip 4B side of a second writing body 3B is arranged in the other end opening of a cap 2 so as to be insertable therein. The first writing body 3A has a pen tip 4A at one end and contains a first thermally-allochroic ink 81A therein. The second writing body 3B has a pen tip 4B at one end and contains a second thermally allochroic ink 81B therein. Friction portions 5A, 5B are arranged at least at the opposite end of the pen tip side of the first writing body 3A or the opposite end of the pen tip side of the second writing body 3B. The handwriting with the first thermally-allochroic ink 81A and the handwriting with the second thermally-allochroic ink 81B are rubbed with the friction portions 5A, 5B, respectively, thereby colors of the respective handwriting can be thermally changed by frictional heat generated at that time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a thermochromic writing instrument. In detail, it is related with the thermochromic writing instrument which incorporated the thermochromic ink.

Conventionally, in a thermochromic writing instrument incorporating a thermochromic ink, Patent Document 1 discloses a configuration in which a friction body for thermally discoloring a handwriting by a thermochromic ink by frictional heat is provided on the top of the cap. The structure provided in the rear end is described.

JP 2004-148744 A

The conventional thermochromic writing instrument can obtain only one type of handwriting from one writing instrument. Therefore, in order to obtain two types of handwriting (for example, handwriting with different pen tip types and ink colors), two writing tools are required, and the total number of writing tools to be prepared increases, which is inconvenient for carrying and storage.

The present invention is intended to solve the above-mentioned conventional problems, and to provide a thermochromic writing instrument capable of obtaining two types of handwriting using thermochromic ink with a single writing instrument.

In the first invention of the present application, both ends of the cap 2 are open, the one end opening of the cap 2 is provided so that the pen tip 4A side of the first writing body 3A can be inserted, and the other end opening of the cap 2 is opened. The pen part 4B side of the second cursive body 3B is provided to be inserted in the part, the first cursive body 3A is provided with the pen nib 4A at one end, and the first thermochromic ink 81A is accommodated therein. The first thermochromic ink 81A is configured to be ejected from the nib 4A of the first writing body 3A, and the second writing body 3B has a nib 4B at one end and a second inside. The thermochromic ink 81B is accommodated, and the second thermochromic ink 81B is configured to be ejected from the pen tip 4B of the second writing body 3B, and at least on the side opposite to the pen tip of the first writing body 3A. Friction parts 5A and 5B are provided at the end or the end of the second writing body 3B on the side opposite to the pen tip. Each of the handwriting by the first thermochromic ink 81A and the handwriting by the second thermochromic ink 81B is rubbed by the friction portions 5A and 5B, and each of the handwriting is thermally discolored by frictional heat generated at that time. Require it to be possible.

The thermochromic writing instrument 1 of the first invention can obtain two types of handwriting with thermochromic ink with a single writing instrument. In the thermochromic writing instrument 1 of the first invention, each of the handwriting of the first thermochromic ink 81A by the pen tip 4A and the handwriting of the second thermochromic ink 81B by the pen tip 4B is a friction portion. Since heat discoloration is possible with 5A and 5B, the handwriting of the first thermochromic ink 81A and the handwriting of the second thermochromic ink 81B (ie, two types of handwriting) are heated at once by the friction portions 5A and 5B. Can be discolored.

The nib 4A and nib 4B of the first invention are formed by, for example, extrusion molding of a synthetic resin having a ball-point pen tip, a porous pen body (fiber processed body or porous bubble body), and an axial capillary passage. Any of a pen body, a metal plate pen body having a slit at the tip, a brush pen body, and the like may be used. The friction parts 5A and 5B may be provided on both the first writing body 3A and the second writing body 3B, or provided on either the first writing body 3A or the second writing body 3B. Also good.

The second invention of the present application is that, in the first invention, the color of the colored state of the first thermochromic ink 81A is different from the color of the colored state of the second thermochromic ink 81B. And

In the thermochromic writing instrument 1 of the second invention, two types of handwriting having different colors in color developed by the first thermochromic ink 81A and the second thermochromic ink 81B are applied to the friction parts 5A and 5B. It can be discolored by heat at once. Further, the thermochromic writing instrument 1 of the second invention has different color development states even when the handwriting of the first thermochromic ink 81A and the handwriting of the second thermochromic ink 81B overlap. The two types of handwriting can be identified by color.

According to a third invention of the present application, in the first or second invention, the frictional heat of the friction portions 5A and 5B of each of the first thermochromic ink 81A and the second thermochromic ink 81B is used. It is a requirement that the discoloration temperature is set to 25 ° C to 95 ° C (preferably 36 ° C to 90 ° C).

The thermochromic writing instrument 1 according to the third aspect of the present invention reliably produces two types of handwriting by the first thermochromic ink 81A and the second thermochromic ink 81B by frictional heat generated by the friction portions 5A and 5B. Can be discolored at a time. If one of the color change temperature of the first thermochromic ink 81A and the color change temperature of the second thermochromic ink 81B is out of the temperature range, the two types of handwriting are applied to the friction portions 5A and 5B. There is a possibility that heat discoloration cannot be performed at once due to frictional heat.

The thermochromic writing instrument 1 according to the fourth invention of the present application is the nib 4A of the first writing body 3A and the nib 4B of the second writing body 3B in the first, second or third invention. Is made of a ballpoint pen tip.

The thermochromic writing instrument 1 of the fourth invention can obtain the handwriting of two types of thermochromic ink using a ballpoint pen tip with a single writing instrument.

The thermochromic writing instrument 1 of the fifth invention of the present application is the pen tip 4A of the first writing body 3A and the pen tip 4B of the second writing body 3B in the first, second or third invention. Is made of a porous pen body.

The thermochromic writing instrument 1 according to the fifth aspect of the invention can obtain the handwriting of two types of thermochromic ink using a porous pen body with one writing instrument.

Friction part In the present invention, the friction parts 5A and 5B are preferably made of a soft material. Examples of the soft material constituting the friction portions 5A and 5B include elastic resins (rubbers and elastomers), such as silicone resins, SBS resins (styrene-butadiene-styrene copolymers), SEBS resins (styrene- Ethylene-butadiene-styrene copolymer), fluorine resin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM), and the like. The soft material constituting the friction portions 5A and 5B is made of a low-wearing elastic material rather than a high-wearing elastic material (for example, an eraser). It is. The friction portions 5A and 5B are formed integrally with the rear end of the writing body by two-color molding, or the friction portions 5A and 5B made of a separate part from the writing body are fixed to the rear end of the writing body (for example, fitting) , Press-fitting, screwing, and bonding).

-Pen tip The ball-point pen tip has a configuration in which a ball is rotatably held at the tip of the tip body. In addition, it is effective that the ballpoint pen tip is configured such that the ball is urged forward from the inside of the tip body by a projectile and the ball is pressed against the inner surface of the crimping portion (tip edge portion) of the tip body.

Examples of the porous pen body include a pen body made of a fiber processed body or a porous foam body. The porous pen body has a tip portion formed in a chisel shape or a shell shape.

-Thermochromic ink In the present invention, the thermochromic ink is preferably a reversible thermochromic ink. The reversible thermochromic ink is a heat decoloring type that decolors by heating from a colored state, a color memory retaining type that reversibly stores and retains a colored state or a decolored state in a specific temperature range, or from a decolored state Various types such as a heating coloring type that develops color by heating and returns to a decolored state by cooling from the colored state can be used alone or in combination.

The coloring material contained in the reversible thermochromic ink includes conventionally known (a) electron donating color-forming organic compounds, (b) electron-accepting compounds, and (c) color reactions of both. A reversible thermochromic microcapsule pigment in which a reversible thermochromic composition containing at least three essential components of a reaction medium for determining the occurrence temperature of the microcapsule is preferably used.

In the present invention, as shown in FIG. 3, the shape of the curve plotting the change in color density due to the temperature change is opposite to the case where the temperature is raised from the lower temperature side than the color change temperature range, and from the higher temperature side than the color change temperature range. The color changes by following a different path depending on the descending state, and the color development state in the low temperature range below the complete color development temperature (t ₁ ) or the color erase state in the high temperature range above the complete color erase temperature (t ₄ ) It is preferable to apply a color memory retention type thermochromic ink that can be stored and retained in a specific temperature range [temperature range between t _{2 and} t ₃ (substantially two-phase retention temperature range)]. In FIG. 3, ΔH indicates a temperature width (ie, hysteresis width) indicating the degree of hysteresis. When the value of ΔH is small, only one of the two states before and after the color change can exist. When the value of ΔH is large, it is easy to maintain each state before and after the color change.

In the present invention, the color change temperature due to frictional heat of the friction body of the thermochromic ink is set to 25 ° C. to 95 ° C. (preferably 36 ° C. to 95 ° C.). That is, in the present invention, the high temperature side discoloration point [complete decoloring temperature (t ₄ )] is set in a range of 25 ° C. to 95 ° C. (preferably 36 ° C. to 90 ° C.), and the low temperature side discoloration point [ It is effective to set the complete color development temperature (t ₁ )] in the range of −30 ° C. to + 20 ° C. (preferably −30 ° C. to + 10 ° C.). Accordingly, it is possible to effectively maintain the color exhibited in the normal state (daily life temperature range), and it is possible to easily change the color of the image or handwriting by the reversible thermochromic ink by the frictional heat generated by the friction body.

The reversible thermochromic microcapsule pigment preferably has an average particle diameter in the range of 0.5 to 5.0 μm, preferably 1 to 4 μm. When the average particle diameter exceeds 5.0 μm, the outflow from the capillary gap of the ballpoint pen tip or the porous pen body decreases, and when the average particle diameter is 0.5 μm or less, it is difficult to show high density color development. .

The reversible thermochromic microcapsule pigment can be blended in an amount of 2 to 50% by weight (preferably 3 to 40% by weight, more preferably 4 to 30% by weight) based on the total amount of the ink composition. If it is less than 2% by weight, the color density is insufficient, and if it exceeds 50% by weight, the ink outflow is reduced and the writing property is impaired.

The present invention can obtain two types of handwriting with thermochromic ink with a single writing instrument.

<First Embodiment>
A first embodiment of the thermochromic writing instrument 1 of the present invention is shown in FIG.
The thermochromic writing instrument 1 according to the present embodiment includes a cap 2 having both ends opened, a first writing body 3A that can be removably attached to one end of the cap 2, and a removable second end of the cap 2. And a second cursive body 3B that can be inserted into the body.

First cursive body The first cursive body 3A has a nib 4A at one end and contains a first thermochromic ink 81A inside, and the first thermochromic ink 81A is provided from the nib 4A. Is configured to be capable of discharging.

The first writing body 3A includes a shaft cylinder 6A and a refill accommodated in the shaft cylinder 6A.

The shaft cylinder 6A includes a front shaft 61A and a rear shaft 62A attached to the rear end of the front shaft 61A. The front shaft 61A is detachably attached to the rear shaft 62A by screwing. A tip hole is formed through the tip of the tip shaft 61A, and the pen tip 4A projects therefrom. A friction portion 5A made of a soft material (for example, SBS resin, SEBS resin) is attached to the rear end of the rear shaft 62A (shaft cylinder 6A). The friction portion 5A can be integrally formed with the rear shaft 62A by two-color molding.

The refill has a nib 4A made of a ballpoint pen tip at the tip, and contains the first thermochromic ink 81A. The first thermochromic ink 81A is ejected to the outside from the pen tip 4A, and a handwriting by the first thermochromic ink 81A can be obtained. A bullet (spring) is accommodated in the nib 4A. The ball of the nib 4A is urged forward by the bullet and is brought into pressure contact with the inward caulking part inner surface (front end edge inner surface) of the nib 4A, and ink leakage from the nib when not writing and Prevent air contamination.

The pen tip 4A is attached to the ink containing cylinder 8A via a pen tip holder 7A. Specifically, the pen tip 4A is fixed to the tip of the pen tip holder 7A, and the rear end of the pen tip holder 7A is fixed to the opening of the ink containing cylinder 8A. The pen tip holder 7A has a flange on the outer peripheral surface, and the flange is sandwiched between the inner surface of the front shaft 61A and the tip of the rear shaft 62A.

First thermochromic ink The first thermochromic ink 81A has a low temperature side discoloration point (complete color development temperature t ₁ ) set to an arbitrary temperature in the range of −30 ° C. to −10 ° C. A reversible thermochromic ink having a discoloration point (complete decoloring temperature t ₄ ) set to an arbitrary temperature in the range of 60 ° C. to 80 ° C. and a hysteresis width ΔH in the range of 40 ° C. to 60 ° C. is employed.

A first thermochromic ink 81A is accommodated in the ink storage cylinder 8A. A follower 82A is accommodated at the rear end of the first thermochromic ink 81A in the ink accommodating cylinder 8A. The follower 82A moves forward as the ink is consumed and prevents the ink from retreating (that is, backflow). For example, the follower 82A can move a solid object in a highly viscous fluid, a movable stopper made of an elastic material, or a highly viscous fluid. Examples include a housed configuration.

Second cursive body The second cursive body 3B has a nib 4B at one end and a second thermochromic ink 81B is accommodated therein, and the second thermochromic ink 81B from the nib 4B. Is configured to be capable of discharging.

The second cursive body 3B includes a shaft cylinder 6B and a refill accommodated in the shaft cylinder 6B.

The shaft cylinder 6B includes a front shaft 61B and a rear shaft 62B attached to the rear end of the front shaft 61B. The front shaft 61B is detachably attached to the rear shaft 62B by screwing. A tip hole is formed through the tip of the tip shaft 61B, and the pen tip 4B projects therefrom. A friction portion 5B made of a soft material (for example, SBS resin, SEBS resin) is attached to the rear end of the rear shaft 62B (shaft cylinder 6B). The friction portion 5B can be integrally formed with the rear shaft 62B by two-color molding.

The refill has a nib 4B made of a ballpoint pen tip at the tip, and the second thermochromic ink 81B is accommodated therein. The second thermochromic ink 81B is ejected to the outside from the pen tip 4B, and handwriting by the second thermochromic ink 81B can be obtained. A bullet (spring) is accommodated in the nib 4B. The ball of the nib 4B is urged forward and pressed against the inward caulking portion inner surface (inner end edge inner surface) of the nib 4B by the bullet, and ink leakage from the nib when not writing and Prevent air contamination.

The nib 4B is attached to the ink containing cylinder 8B via the nib holder 7B. Specifically, the pen tip 4B is fixed to the tip of the pen tip holder 7B, and the rear end of the pen tip holder 7B is fixed to the opening of the ink containing cylinder 8B. The pen tip holder 7B has a flange on the outer peripheral surface, and the flange is sandwiched between the inner surface of the front shaft 61B and the tip of the rear shaft 62B.

Second thermochromic ink The second thermochromic ink 81B has a low temperature side color change point (complete color development temperature t ₁ ) set to an arbitrary temperature in the range of −30 ° C. to −10 ° C. A reversible thermochromic ink having a discoloration point (complete decoloring temperature t ₄ ) set to an arbitrary temperature in the range of 60 ° C. to 80 ° C. and a hysteresis width ΔH in the range of 40 ° C. to 60 ° C. is employed.

A second thermochromic ink 81B is accommodated in the ink storage cylinder 8B. A follower 82B is accommodated at the rear end of the second thermochromic ink 81B in the ink accommodating cylinder 8B. The follower 82B moves forward with the consumption of ink and prevents the ink from retreating (that is, backflow). For example, the follower 82B can move a solid object into a highly viscous fluid, a movable stopper made of an elastic material, or a highly viscous fluid. Examples include a housed configuration.

The color of the colored state of the first thermochromic ink 81A is different from the color of the colored state of the second thermochromic ink 81B.

Cap The cap 2 is a cylindrical member having openings at both ends obtained by injection molding of synthetic resin. A first accommodating portion 21A into which the pen tip 4A side of the first writing body 3A can be inserted is provided at one end opening of the cap 2, and the second writing body 3B is provided at the other end opening of the cap 2. A second housing portion 21B is provided in which the pen tip 4B side can be inserted. A pen nib seal member 22A made of an elastic material is accommodated in the first accommodating part 21A, and a nib seal member 22B is accommodated in the second accommodating part 21B. When the pen tip 4A side of the first writing body 3A is inserted into the first accommodating portion 21A, the pen tip seal member 22A and the tip of the pen tip 4A are in close contact, and the tip of the pen tip 4A is sealed. The On the other hand, when the pen tip 4B side of the second writing body 3B is inserted into the second accommodating portion 21B, the pen tip seal member 22B and the tip of the pen tip 4B are in close contact, and the tip of the pen tip 4B is Sealed.

In the present embodiment, the one end opening of the cap 2 (that is, the first housing portion 21A) has either the pen tip 4A side of the first writing body 3A or the pen tip 4B side of the second writing body 3B. And the pen end of the second writing body 3B and the pen tip of the second writing body 3B are arranged in the other end opening of the cap 2 (that is, the second accommodating portion 21B). All of the 4B sides are configured to be insertable. In the present embodiment, both the rear end portion of the first writing body 3A and the rear end portion of the second writing body 3B are located at one end opening of the cap 2 (that is, the first housing portion 21A). Any one of the rear end portion of the first cursive body 3A and the rear end portion of the second cursive body 3B can be inserted into the cap 2 and the other end opening of the cap 2 (that is, the second accommodating portion 21B). Is configured to be insertable.

<Second Embodiment>
A second embodiment of the thermochromic writing instrument 1 of the present invention is shown in FIG.
The thermochromic writing instrument 1 according to the present embodiment includes a cap 2 having both ends opened, a first writing body 3A that can be removably attached to one end of the cap 2, and a removable second end of the cap 2. And a second cursive body 3B that can be inserted into the body.

First cursive body The first cursive body 3A has a nib 4A at one end and contains a first thermochromic ink therein, and the first thermochromic ink is discharged from the nib 4A. Configured to be possible.

The first writing body 3A includes a shaft tube 6A, a pen tip 4A attached to the tip of the shaft tube 6A, an ink occlusion body 9A accommodated in the shaft tube 6A, and a rear end of the shaft tube 6A. And a friction portion 5A attached to the.

The nib 4A is made of a porous pen body. The nib 4A is attached to the tip of the shaft cylinder 6A through a nib holder 7A. The rear end of the nib 4A is connected to the ink occlusion body 9A. The ink occlusion body 9A is made of a member having continuous pores that can be impregnated with thermochromic ink, for example, a porous material such as a fiber processed body or a porous foam. The ink occlusion body 9A is impregnated with the first thermochromic ink.

The friction part 5A is made of a soft material (for example, SBS resin, SEBS resin). The friction portion 5A can be integrally formed with the shaft cylinder 6A by two-color molding.

In the first thermochromic ink, the low temperature side color change point (complete color development temperature t ₁ ) is set to an arbitrary temperature in the range of −30 ° C. to −10 ° C., and the high temperature side color change point (complete color disappearance temperature t _4). ) Is set to an arbitrary temperature in the range of 60 ° C. to 80 ° C., and a reversible thermochromic ink having a hysteresis width ΔH in the range of 40 ° C. to 60 ° C. is employed.

Second cursive body The second cursive body 3B has a nib 4B at one end and contains the second thermochromic ink 81B inside, and the second thermochromic ink is received from the nib 4B. It is configured to allow discharge.

The second writing body 3B includes a shaft cylinder 6B, a pen tip 4B attached to the tip of the shaft cylinder 6B, an ink storage body 9B accommodated in the shaft cylinder 6B, and a rear end of the shaft cylinder 6B. And a friction portion 5B attached to the.

The nib 4B is made of a porous pen body. The nib 4B is attached to the tip of the shaft cylinder 6B via a nib holder 7B. The rear end of the nib 4B is connected to the ink occluding body 9B. The ink occlusion body 9B is made of a member having continuous pores that can be impregnated with thermochromic ink, for example, a porous material such as a fiber processed body or a porous foam. The ink occlusion body 9B is impregnated with the second thermochromic ink.

The friction part 5B is made of a soft material (for example, SBS resin, SEBS resin). The friction portion 5B can be integrally formed with the shaft cylinder 6B by two-color molding.

In the second thermochromic ink, the low temperature side color change point (complete color development temperature t ₁ ) is set to an arbitrary temperature in the range of −30 ° C. to −10 ° C., and the high temperature side color change point (complete color disappearance temperature t _4). ) Is set to an arbitrary temperature in the range of 60 ° C. to 80 ° C., and a reversible thermochromic ink having a hysteresis width ΔH in the range of 40 ° C. to 60 ° C. is employed.

Note that the color of the colored state of the first thermochromic ink is different from the color of the colored state of the second thermochromic ink.

Cap The cap 2 is a cylindrical member having openings at both ends obtained by injection molding of synthetic resin. A first accommodating portion 21A into which the pen tip 4A side of the first writing body 3A can be inserted is formed at one end opening of the cap 2. In the other end opening of the cap 2, a second storage portion 21B is formed into which the pen tip 4B side of the second writing body 3B can be inserted. A partition wall 23 is provided in the cap 2, and the first storage portion 21A and the second storage portion 21B are partitioned in a non-communication state. When the pen tip 4A side of the first writing body 3A is inserted into the first housing portion 21A, the inner surface of the first housing portion 21A and the outer surface of the shaft cylinder 6A are hermetically fitted, and the pen tip 4A is sealed. The On the other hand, when the pen tip 4B side of the second writing body 3B is inserted into the second storage portion 21B, the inner surface of the second storage portion 21B and the outer surface of the shaft tube 6B are airtightly fitted, and the pen tip 4B is Sealed.

In the present embodiment, the one end opening of the cap 2 (that is, the first housing portion 21A) has either the pen tip 4A side of the first writing body 3A or the pen tip 4B side of the second writing body 3B. And the pen end of the second writing body 3B and the pen tip of the second writing body 3B are arranged in the other end opening of the cap 2 (that is, the second accommodating portion 21B). All of the 4B sides are configured to be insertable. In the present embodiment, both the rear end portion of the first writing body 3A and the rear end portion of the second writing body 3B are located at one end opening of the cap 2 (that is, the first housing portion 21A). Any one of the rear end portion of the first cursive body 3A and the rear end portion of the second cursive body 3B can be inserted into the cap 2 and the other end opening of the cap 2 (that is, the second accommodating portion 21B). Is configured to be insertable.

It is a longitudinal cross-sectional view of the 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the 2nd Embodiment of this invention. It is explanatory drawing which shows the discoloration behavior of a reversible thermochromic composition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermochromic writing instrument 2 Cap 21A 1st accommodating part 21B 2nd accommodating part 22A Pen tip sealing member 22B Pen tip sealing member 23 Partition 3A 1st writing body 4A Pen tip 5A Friction part 6A Shaft cylinder 61A Lead shaft 62A Rear shaft 7A Nib holder 8A Ink storage cylinder 81A First thermochromic ink 82A Follower 9A Ink occlusion body 3B Second writing body 4B Nib 5B Friction part 6B Shaft cylinder 61B Front shaft 62B Rear shaft 7B Nib holder 8B Ink receiving cylinder 81B Second thermochromic ink 82B Follower 9B Ink occlusion body

Claims (5)

Both ends of the cap are opened, the pen tip side of the first cursive body is slidably provided in one end opening portion of the cap, and the pen tip side of the second cursive body is provided in the other end opening portion of the cap. The first cursive body is provided so as to be insertable, and the first thermochromic ink is provided with a nib at one end and contains the first thermochromic ink therein, and the first thermochromic property from the nib of the first cursive body. The second writing body is provided with a pen tip at one end, and a second thermochromic ink is accommodated therein, and a second heat is applied from the pen tip of the second writing body. The first thermal discoloration is configured so that the color-changing ink can be discharged, and a friction portion is provided at least at an end of the first writing body on the side opposite to the pen tip or an end of the second writing body on the side of the pen tip. The friction part rubs each of the handwriting with the property ink and the handwriting with the second thermochromic ink, Thermochromic writing instrument, wherein each of said handwriting can be thermochromic Jill frictional heat. The thermochromic writing instrument according to claim 1, wherein the color of the colored state of the first thermochromic ink is different from the color of the colored state of the second thermochromic ink. The thermochromic writing instrument according to claim 1 or 2, wherein each of the first thermochromic ink and the second thermochromic ink has a discoloration temperature of 25 ° C to 95 ° C due to frictional heat of the friction part. The thermochromic writing instrument according to claim 1, 2, or 3, wherein the pen tip of the first cursive body and the pen tip of the second cursive body comprise ballpoint pen tips. The thermochromic writing instrument according to claim 1, 2 or 3, wherein the pen tip of the first cursive body and the pen tip of the second cursive body comprise a porous pen body.

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