JP2014128929A - Thermochromic writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermochromic writing instrument which can prevent friction body from becoming dirty when not in use.SOLUTION: In a thermochromic writing instrument, an operation part 5 being movable in a front-back direction along a side wall of a barrel 2 is protruded. A pen point 31 of a writing body 3 is formed to be capable of appearing and disappearing from a front end hole 24 of the barrel 2 by slide operation of the operation part 5 in the front direction. A friction body 4 is protruded at a rear end of the barrel 2. A protective piece part 6 is arranged at a rear end of the operation part 5, and is movable integrally with the operation part 5 in the front-back direction. When the pen point 31 is disappeared, the rear end of the protective piece part 6 is positioned behind the apex of a projection 41 of the friction body 4, and the protective piece part 6 is positioned at at least one side of an outer periphery of the projection 41 of the friction body 4. When the pen point 31 is appeared, the apex of the projection 41 of the friction body 4 is positioned behind the rear end of the protective piece part 6, and the protective piece part 6 is positioned at at least one side of an outer periphery of the rear end part of the barrel 2.

Description

The present invention relates to a thermochromic writing instrument. Specifically, the cursive body is accommodated in the shaft cylinder so as to be movable in the front-rear direction, and the pen tip of the cursive body is configured to be able to appear and retract from the front end hole of the shaft cylinder by sliding the operation unit forward. The present invention relates to a thermochromic writing instrument comprising a friction body capable of rubbing the handwriting of the thermochromic ink at the rear end of the cylinder and thermally discoloring the handwriting by frictional heat generated at that time.

Conventionally, in Patent Document 1, in a thermochromic writing instrument, a writing body containing a thermochromic ink is accommodated in a shaft cylinder, and an operation body provided on the shaft cylinder is operated to move the writing body forward and backward. The thermochromic writing tool is configured to move in the direction so that the pen tip of the writing body can be projected and retracted from the tip of the writing instrument, and the handwriting of the thermochromic ink is rubbed to heat the handwriting with frictional heat generated at that time. A discolorable friction portion and at least one clip body as the operation body are provided, and the friction portion is provided at a rear end of the shaft tube, and the clip body is provided at a portion other than the rear end of the shaft tube. A thermochromic writing instrument characterized by the above is disclosed.

Japanese Unexamined Patent Publication No. 2012-6315

In the thermochromic writing instrument of Patent Document 1, the friction body is always exposed to the outside. Therefore, when not in use, the user's fingertip comes into contact with the friction body, or when the thermochromic writing instrument is stored in a storage body (for example, a pen case, a pen stand, or a clothes pocket), the storage is performed. When the inner surface of the body (for example, the inner surface of the pen case, the bottom surface of the pen stand, or the inner surface of the pocket of clothes) contacts the friction body, dirt or dust adheres to the friction body surface, and the friction body surface becomes dirty. Further, when the paper surface is rubbed with the dirty friction body, the paper surface becomes dirty.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a thermochromic writing instrument that can prevent the friction body from becoming dirty when not in use.

In the present invention, “front” refers to the pen tip side, and “rear” refers to the opposite friction body side.

1st invention of this application accommodates the writing body 3 in the axial cylinder 2 so that a movement in the front-back direction is possible, accommodates the thermochromic ink 34 in the inside of the writing body 3, and the front end of the writing body 3 A pen nib 31 capable of discharging the thermochromic ink 34 is provided, and an operation unit 5 that can move in the front-rear direction is projected on a side wall of the shaft tube 2, and the operation unit 5 is slid forward to perform the writing. The nib 31 of the body 3 is configured to be able to protrude and retract from the front end hole 24 of the shaft tube 2, and the handwriting of the thermochromic ink 34 is rubbed behind the rear end of the shaft tube 2 by frictional heat generated at that time. A thermochromic writing instrument in which a friction body 4 made of a low-abrasion elastic material capable of thermally discoloring a handwriting is projected, and moves in the front-rear direction integrally with the operation unit 5 at the rear end of the operation unit 5 A protective piece 6 is provided, and the rear end of the protective piece 6 protrudes from the friction body 4 when the pen tip is immersed. 41 is located rearward from the top, and the protection piece 6 is located at least on one side outer periphery of the protrusion 41 of the friction body 4, and when the pen tip protrudes, the protrusion 41 top of the friction body 4 is the protection piece 6. It is a requirement that it is located behind the rear end and that the protective piece 6 is located on at least one outer periphery of the rear end of the shaft cylinder 2.

In the thermochromic writing instrument 1 of the first invention, when the pen tip is immersed, the rear end of the protective piece 6 is located behind the top of the protrusion 41 of the friction body 4 and the protective piece 6 is at least By being located on the outer periphery of one side of the protrusion 41 of the friction body 4, when not in use (when the pen tip is not used or when the friction body is not used), contact with the user's fingertips, or the friction body 4 and the inner surface of the container (for example, Further, it is possible to avoid contact with the inner surface of the pen case, the bottom surface of the pen stand, or the inner surface of the pocket of the clothes, and it is possible to prevent dirt, dust and the like from adhering to the friction body 4 (that is, the friction body 4 becomes dirty). In addition, the thermochromic writing instrument 1 of the present invention can simultaneously move the pen tip 31 and the friction body 4 by the operation of the operation unit 5, and is easy to operate and visually recognizes one of the protruding and protruding states. Only the infestation state on the opposite side can be identified. (For example, the pen tip appearance state can be identified by visually recognizing the appearance state of the friction body 4. Alternatively, the appearance state of the friction body 4 can be identified by visual recognition of the pen tip appearance state.)

2nd invention of this application makes it a requirement in the said 1st invention that the said operation part 5 and the said protection piece part 6 are arrange | positioned with respect to the said friction body 4 on the same side.

In the thermochromic writing instrument 1 according to the second aspect of the present invention, the operation unit 5 and the protective piece 6 are arranged on the same side with respect to the friction body 4, so that the friction body 4 is operated when the operation section 5 is slid. It is possible to prevent the finger from coming into contact with the friction member 4 and to further prevent the friction body 4 from becoming dirty.

According to a third invention of the present application, in the thermochromic writing instrument 1 of the first invention or the second invention, a step portion 61 facing rearward is formed on the outer surface of the protective piece portion 6 or the outer surface of the operation portion 5. It is a requirement that

In the thermochromic writing instrument 1 according to the third aspect of the present invention, a step portion 61 facing rearward is formed on the outer surface of the protective piece portion 6 or the outer surface of the operation portion 5, so that the step portion 61 is touched with a finger. By making contact and pressing forward, the operation unit 5 can be easily slid. Further, the thermochromic writing instrument 1 of the third aspect of the invention can prevent the finger from coming into contact with the friction body 4 during the sliding operation of the operation section 5, and can further prevent the friction body 4 from becoming dirty.

The thermochromic writing instrument of the present invention can prevent the friction body from becoming dirty when not in use.

It is a longitudinal cross-sectional view which shows the time of non-use of the 1st Embodiment of this invention. It is a longitudinal cross-sectional view which shows the time of use of FIG. It is a side view of FIG. It is a front view of FIG. FIG. 3 is a side view of FIG. 2. It is a longitudinal cross-sectional view which shows the time of non-use of the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the time of use of FIG.

<First Embodiment>
1 to 5 show a first embodiment of the present invention.
The thermochromic writing instrument 1 of the present embodiment includes a shaft tube 2, a writing body 3 accommodated in the shaft tube 2, an operation unit 5 projecting radially outward from the outer surface of the shaft tube 2, A sliding mechanism is provided that allows the pen point 31 of the writing body 3 to be projected and retracted from the front end hole 24 of the barrel 2 by sliding the operation unit 5 forward.

The cursive body 3 includes a pen tip 31, an ink storage tube 32 in which the pen tip 31 is press-fitted and fixed to a front end opening, a thermochromic ink 34 filled in the ink storage tube 32, and the thermochromic color. And a follower 35 (for example, a high-viscosity fluid) that is filled at the rear end of the ink 34 and moves forward as the thermochromic ink 34 is consumed.

The nib 31 includes, for example, a configuration composed only of a metal ballpoint pen tip holding a ball rotatably at the front end, or a configuration composed of a synthetic resin nib holder holding the rear outer surface of the ballpoint pen tip. It is done. Further, a tail plug 33 having a vent hole through which the ink containing tube 32 and the outside can be vented is attached to the rear end opening of the ink containing tube 32. A spring that presses the ball at the front end forward is housed inside the nib 31. The spring includes a rod portion at a front end portion of a compression coil spring, and the front end of the rod portion is in contact with the rear surface of the ball. When not writing, the ball is brought into close contact with the inner surface of the front end edge portion of the front end of the ballpoint pen tip by the forward urging of the spring, thereby preventing ink leakage and ink evaporation from the front end of the pen tip 31.

The shaft cylinder 2 includes a tapered cylindrical front shaft 21, a cylindrical intermediate shaft 22 connected to the rear end portion of the front shaft 21, and a cylindrical shape connected to the rear end portion of the intermediate shaft 22. It consists of a rear shaft 23. A slide hole 25 extending in the front-rear direction is formed in the rear side wall of the shaft cylinder 2 (side walls of the rear shaft 23 and the intermediate shaft 22). A cam portion 27 is integrally formed on the inner surface of the shaft cylinder 2 (intermediate shaft 22).

A mounting hole 26 is provided through the rear end of the shaft cylinder 2 (the rear end of the rear shaft 23) in the front-rear direction. The friction body 4 made of an elastic material is press-fitted or fitted over the mounting hole 26. Thereby, the friction body 4 is fixed to the outer surface of the rear end of the rear shaft 23. The friction body 4 protrudes rearward from the rear end of the shaft cylinder 2, and a protrusion 41 of the friction body 4 is formed at the rear end of the shaft cylinder 2. The top of the protrusion 41 of the friction body 4 is formed in a convex curved shape.

The operation unit 5 also serves as a clip. The operation unit 5 includes a clip main body 51 extending in the front-rear direction, a base 52 integrally connected to the rear portion of the clip main body 51, and a shaft portion integrally connected to the base 52 and extending forward from the base 52. 53. The operation unit 5 is obtained from a molded body of synthetic resin (for example, polycarbonate resin). The clip main body 51 has a ball portion 51a protruding from the back surface. At the front end of the shaft portion 53, cam teeth that engage with the rotating member 7 are formed integrally or by attachment by another member.

At the rear end of the operation portion 5 (clip body), a protective piece portion 6 that moves integrally with the operation portion 5 in the front-rear direction is formed. The operation portion 5 and the protective piece portion 6 are disposed on the same side with respect to the friction body 4. The protective piece 6 is disposed so as to move in the front-rear direction on the radially outer side of the rear end portion of the shaft cylinder 2 and on the radially outer side of the friction body 4. The protective piece 6 is formed in a planar shape, a curved surface shape or a rod shape. The protective piece 6 is formed integrally with the operation unit 5 or is formed by attaching another member.

At the time of pen tip immersion, the rear end of the protection piece 6 is located behind the top of the protrusion 41 of the friction body 4 and the protection piece 6 is mainly located on one side outer periphery of the protrusion 41 of the friction body 4. To do. When the pen tip protrudes, the top of the protrusion 41 of the friction body 4 is located rearward from the rear end of the protective piece 6, and the protective piece 6 is mainly located on one side outer periphery of the rear end of the shaft cylinder 2. To do.

The in / out mechanism is a side slide type in / out mechanism using a rotating cam mechanism. The retracting mechanism includes a cam portion 27 formed on the inner surface of the intermediate shaft 22, a rotating member 7 that engages with the cam portion 27 and abuts against the rear end of the writing body 3, engages with the rotating member 7, and The operation portion 5 protrudes radially outward from the slide hole 25 and the elastic body 8 (for example, a compression coil spring) accommodated in the shaft cylinder 2 and biases the writing body 3 backward. The retracting mechanism of the present embodiment is a double knock type in which both the pen tip protruding operation and the pen tip retracting operation slide the operation unit 5 forward.

When the operation unit 5 (clip body) is slid forward from the pen tip immersion state against the rearward urging by the elastic body 8, the rotation member 7 is pressed forward by the operation unit 5, and the rotation member 7. Presses the rear end of the cursive body 39 forward, and the nib 31 protrudes from the front end hole 24 to the outside. At this time, the rotating member 7 is engaged with the cam portion 27, and the pen tip protruding state is maintained. At the same time, the protective piece 6 moves forward as the operation portion 5 moves forward, and the top of the protrusion 41 of the friction body 4 is positioned behind the rear end of the protective piece 6 ( That is, the protrusion 41 of the friction body 4 is exposed from the inside of the protective piece 6). Thereby, it will be in a usable state (a writing possible state and a friction body usable state).

Next, when the operating portion 5 (clip body) is slid forward from the pen tip protruding state, the writing body 3 and the operating body are moved along with the backward movement of the rotating member 7 due to the engagement of the cam portion 27 and the rotating cam. Moves backward and enters the nib immersive state. As the operation unit 5 moves rearward, the protection piece 6 moves rearward, and the rear end of the protection piece 6 is positioned behind the protrusion 41 of the friction body 4 (that is, the protrusion 41 of the friction body 4). Is immersed in the protective piece 6). Thereby, it will be in a non-use state (a writing non-use state and a friction body non-use state).

In the present embodiment, the elastic material constituting the friction body 4 is preferably an elastic synthetic resin (rubber or elastomer), such as a silicone resin, an SBS resin (styrene-butadiene-styrene copolymer), or an SEBS resin. (Styrene-ethylene-butadiene-styrene copolymer), fluorine resin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM) and the like. The elastic synthetic resin constituting the friction body 4 is not a highly wearable elastic material (for example, an eraser) but a low wear elastic material that hardly generates wear debris (erasure debris) during friction. The friction body 4 may be provided at least on the outer surface of the rear end portion of the shaft cylinder 2, for example, the friction body 4 made of an elastic material on the outer surface of the rear end portion of the shaft cylinder 2 or the outer surface of the rear end portion of the rear shaft 23. Can be fixed by press-fitting, engagement, screwing, fitting, adhesion, two-color molding, or the like, or a configuration in which the entire shaft cylinder 2 or the entire rear shaft 23 is integrally formed of an elastic material.

In the thermochromic writing instrument 1 of the present embodiment, when the pen tip is immersed, the rear end of the protection piece 6 is located behind the top of the protrusion 41 of the friction body 4 and the protection piece 6 is at least the friction. The protrusion 4 of the body 4 is located on the outer periphery on one side, so that when not in use (when the pen tip is not used and when the friction body is not used), the contact with the user's fingertips, the friction body 4 and the inner surface of the container (for example, the pen) Contact with the inner surface of the case, the bottom surface of the pen stand, or the inner surface of the pocket of the clothes) can be avoided, and adhesion of dirt or dust to the friction body 4 (that is, contamination of the friction body 4) can be prevented. In addition, the thermochromic writing instrument 1 of the present invention can simultaneously move the pen tip 31 and the friction body 4 by the operation of the operation unit 5, and is easy to operate and visually recognizes one of the protruding and protruding states. Only the infestation state on the opposite side can be identified. (For example, the pen tip appearance state can be identified by visually recognizing the protrusion state of the friction body 4. Alternatively, the protrusion state of the friction body 4 can be identified by visually confirming the protrusion state of the pen tip 31.)

The thermochromic writing instrument 1 according to the present embodiment is arranged on the friction body 4 when the operation section 5 is slid by the operation section 5 and the protective piece section 6 being arranged on the same side with respect to the friction body 4. It can avoid that a finger contacts, and can prevent further that the friction body 4 becomes dirty.

<Second Embodiment>
6 and 7 show a second embodiment of the present invention. The second embodiment mainly differs from the first embodiment in that a stepped portion 61 is provided on the outer surface of the protective piece 6 or the outer surface of the operation unit 5.

The thermochromic writing instrument 1 of the present embodiment includes a shaft tube 2, a writing body 3 accommodated in the shaft tube 2, an operation unit 5 projecting radially outward from the outer surface of the shaft tube 2, A sliding mechanism is provided that allows the pen point 31 of the writing body 3 to be projected and retracted from the front end hole 24 of the barrel 2 by sliding the operation unit 5 forward.

The cursive body 3 includes a pen tip 31, an ink storage tube 32 in which the pen tip 31 is press-fitted and fixed to a front end opening, a thermochromic ink 34 filled in the ink storage tube 32, and the thermochromic color. And a follower 35 (for example, a high-viscosity fluid) that is filled at the rear end of the ink 34 and moves forward as the thermochromic ink 34 is consumed.

The nib 31 includes, for example, a configuration composed only of a metal ballpoint pen tip holding a ball rotatably at the front end, or a configuration composed of a synthetic resin nib holder holding the rear outer surface of the ballpoint pen tip. It is done. Further, a tail plug 33 having a vent hole through which the ink containing tube 32 and the outside can be vented is attached to the rear end opening of the ink containing tube 32. A spring that presses the ball at the front end forward is housed inside the nib 31. The spring includes a rod portion at a front end portion of a compression coil spring, and the front end of the rod portion is in contact with the rear surface of the ball. When not writing, the ball is brought into close contact with the inner surface of the front end edge portion of the front end of the ballpoint pen tip by the forward urging of the spring, thereby preventing ink leakage and ink evaporation from the front end of the pen tip 31.

The shaft cylinder 2 includes a tapered cylindrical front shaft 21, a cylindrical intermediate shaft 22 connected to the rear end portion of the front shaft 21, and a cylindrical shape connected to the rear end portion of the intermediate shaft 22. It consists of a rear shaft 23. A slide hole 25 extending in the front-rear direction is formed in the rear side wall of the shaft cylinder 2 (side walls of the rear shaft 23 and the intermediate shaft 22). A cam portion 27 is integrally formed on the inner surface of the shaft cylinder 2 (intermediate shaft 22).

A mounting hole 26 is provided through the rear end of the shaft cylinder 2 (the rear end of the rear shaft 23) in the front-rear direction. The friction body 4 made of an elastic material is press-fitted or fitted over the mounting hole 26. Thereby, the friction body 4 is fixed to the outer surface of the rear end of the rear shaft 23. The friction body 4 protrudes rearward from the rear end of the shaft cylinder 2, and a protrusion 41 of the friction body 4 is formed at the rear end of the shaft cylinder 2. The top of the protrusion 41 of the friction body 4 is formed in a convex curved shape.

The operation unit 5 also serves as a clip. The operation unit 5 includes a clip main body 51 extending in the front-rear direction, a base 52 integrally connected to the rear portion of the clip main body 51, and a shaft portion integrally connected to the base 52 and extending forward from the base 52. 53. The operation unit 5 is obtained from a molded body of synthetic resin (for example, polycarbonate resin). The clip main body 51 has a ball portion 51a protruding from the back surface. At the front end of the shaft portion 53, cam teeth that engage with the rotating member 7 are formed integrally or by attachment by another member.

At the rear end of the operation portion 5 (clip body), a protective piece portion 6 that moves integrally with the operation portion 5 in the front-rear direction is formed. The operation portion 5 and the protective piece portion 6 are disposed on the same side with respect to the friction body 4. The protective piece 6 is disposed so as to move in the front-rear direction on the radially outer side of the rear end portion of the shaft cylinder 2 and on the radially outer side of the friction body 4. The protective piece 6 is formed in a planar shape, a curved surface shape or a rod shape. The protective piece 6 is formed integrally with the operation unit 5 or is formed by attaching another member. Further, a stepped portion 61 facing rearward is formed on the outer surface of the protective piece portion 6 or the outer surface of the operation portion 5.

At the time of pen tip immersion, the rear end of the protection piece 6 is located behind the top of the protrusion 41 of the friction body 4 and the protection piece 6 is mainly located on one side outer periphery of the protrusion 41 of the friction body 4. To do. When the pen tip protrudes, the top of the protrusion 41 of the friction body 4 is located rearward from the rear end of the protective piece 6, and the protective piece 6 is mainly located on one side outer periphery of the rear end of the shaft cylinder 2. To do.

The in / out mechanism is a side slide type in / out mechanism using a rotating cam mechanism. The retracting mechanism includes a cam portion 27 formed on the inner surface of the intermediate shaft 22, a rotating member 7 that engages with the cam portion 27 and abuts against the rear end of the writing body 3, engages with the rotating member 7, and The operation portion 5 protrudes radially outward from the slide hole 25 and the elastic body 8 (for example, a compression coil spring) accommodated in the shaft cylinder 2 and biases the writing body 3 backward. The retracting mechanism of the present embodiment is a double knock type in which both the pen tip protruding operation and the pen tip retracting operation slide the operation unit 5 forward.

When the operation unit 5 (clip body) is slid forward from the pen tip immersion state against the rearward urging by the elastic body 8, the rotation member 7 is pressed forward by the operation unit 5, and the rotation member 7. Presses the rear end of the cursive body 39 forward, and the nib 31 protrudes from the front end hole 24 to the outside. At this time, the rotating member 7 is engaged with the cam portion 27, and the pen tip protruding state is maintained. At the same time, the protective piece 6 moves forward as the operation portion 5 moves forward, and the top of the protrusion 41 of the friction body 4 is positioned behind the rear end of the protective piece 6 ( That is, the protrusion 41 of the friction body 4 is exposed from the inside of the protective piece 6). Thereby, it will be in a usable state (a writing possible state and a friction body usable state).

Next, when the operating portion 5 (clip body) is slid forward from the pen tip protruding state, the writing body 3 and the operating body are moved along with the backward movement of the rotating member 7 due to the engagement of the cam portion 27 and the rotating cam. Moves backward and enters the nib immersive state. As the operation unit 5 moves rearward, the protection piece 6 moves rearward, and the rear end of the protection piece 6 is positioned behind the protrusion 41 of the friction body 4 (that is, the protrusion 41 of the friction body 4). Is immersed in the protective piece 6). Thereby, it will be in a non-use state (a writing non-use state and a friction body non-use state).

In the present embodiment, the elastic material constituting the friction body 4 is preferably an elastic synthetic resin (rubber or elastomer), such as a silicone resin, an SBS resin (styrene-butadiene-styrene copolymer), or an SEBS resin. (Styrene-ethylene-butadiene-styrene copolymer), fluorine resin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM) and the like. The elastic synthetic resin constituting the friction body 4 is not a highly wearable elastic material (for example, an eraser) but a low wear elastic material that hardly generates wear debris (erasure debris) during friction. The friction body 4 may be provided at least on the outer surface of the rear end portion of the shaft cylinder 2, for example, the friction body 4 made of an elastic material on the outer surface of the rear end portion of the shaft cylinder 2 or the outer surface of the rear end portion of the rear shaft 23. Can be fixed by press-fitting, engagement, screwing, fitting, adhesion, two-color molding, or the like, or a configuration in which the entire shaft cylinder 2 or the entire rear shaft 23 is integrally formed of an elastic material.

In the thermochromic writing instrument 1 of the present embodiment, when the pen tip is immersed, the rear end of the protection piece 6 is located behind the top of the protrusion 41 of the friction body 4 and the protection piece 6 is at least the friction. The protrusion 4 of the body 4 is located on the outer periphery on one side, so that when not in use (when the pen tip is not used and when the friction body is not used), the contact with the user's fingertips, the friction body 4 and the inner surface of the container (for example, the pen) Contact with the inner surface of the case, the bottom surface of the pen stand, or the inner surface of the pocket of the clothes) can be avoided, and adhesion of dirt or dust to the friction body 4 (that is, contamination of the friction body 4) can be prevented. In addition, the thermochromic writing instrument 1 of the present invention can simultaneously move the pen tip 31 and the friction body 4 by the operation of the operation unit 5, and is easy to operate and visually recognizes one of the protruding and protruding states. Only the infestation state on the opposite side can be identified. (For example, the pen tip appearance state can be identified by visually recognizing the protrusion state of the friction body 4. Alternatively, the protrusion state of the friction body 4 can be identified by visually confirming the protrusion state of the pen tip 31.)

The thermochromic writing instrument 1 according to the present embodiment is arranged on the friction body 4 when the operation section 5 is slid by the operation section 5 and the protective piece section 6 being arranged on the same side with respect to the friction body 4. It can avoid that a finger contacts, and can prevent further that the friction body 4 becomes dirty.

In the thermochromic writing instrument 1 according to the present embodiment, a step portion 61 facing rearward is formed on the outer surface of the protective piece portion 6 or the outer surface of the operation portion 5, so that the finger contacts the step portion 61. By pushing forward, the operation unit 5 can be easily slid, the finger can be prevented from coming into contact with the friction body 4 when the operation unit 5 is slid, and the friction body 4 is further contaminated. Can be prevented.

DESCRIPTION OF SYMBOLS 1 Thermochromic writing instrument 2 Shaft cylinder 21 Front shaft 22 Intermediate shaft 23 Rear shaft 24 Front end hole 25 Slide hole 26 Mounting hole 27 Cam part 3 Writing body 31 Pen tip 32 Ink storage pipe 33 Tail plug 34 Thermochromic ink 35 Following body 4 Friction body 41 Projection portion 5 Operation portion 51 Clip body 51a Ball portion 52 Base portion 53 Shaft portion 6 Protection piece portion 61 Step portion 7 Rotating member 8 Elastic body

Claims (3)

A cursive body is accommodated in the shaft cylinder so as to be movable in the front-rear direction, a thermochromic ink is accommodated in the cursive body, and a pen tip capable of discharging the thermochromic ink is provided at the front end of the cursive body The pendant of the writing body can be projected and retracted from the front end hole of the shaft tube by projecting an operation unit movable in the front-rear direction on the side wall of the shaft tube and sliding the operation unit forward. A thermochromic writing instrument in which a friction body made of a low-abrasion elastic material capable of thermally discoloring the handwriting of the thermochromic ink by rubbing the handwriting of the thermochromic ink at the rear end of the cylinder is projected. The rear end of the operating portion includes a protective piece that moves in the front-rear direction integrally with the operating portion, and when the pen tip is immersed, the rear end of the protective piece is more than the top of the protruding portion of the friction body. Located at the rear and the protective piece is at least one side of the protrusion of the friction body When the pen tip protrudes, the top of the protruding portion of the friction body is located behind the rear end of the protective piece portion, and the protective piece portion is located at least on one side outer periphery of the rear end portion of the shaft tube. A thermochromic writing instrument characterized by The thermochromic writing instrument according to claim 1, wherein the operation portion and the protective piece portion are disposed on the same side with respect to the friction body. The thermochromic writing instrument according to claim 1 or 2, wherein a stepped portion facing rearward is formed on an outer surface of the protective piece portion or an outer surface of the operation portion.

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