Thermochromic writing instrument

Abstract

To provide a thermochromic writing instrument that can achieve a stable rubbing operation by using a rubbing part, prevent the rubbing part from being soiled due to finger marks or the like, and increase degree of freedom of appearance design.SOLUTION: A thermochromic writing instrument 1 is configured so that a writing body 9 storing thermochromic ink in the writing body is housed in a barrel 2, the writing body 9 is moved in a forward / backward direction by operating an operation body provided on the barrel 2, and a pen tip 91 of the writing body 9 is allowed to come out from and come into a front end of the writing instrument. The thermochromic writing instrument comprises: a rubbing part 10 that rubs against handwriting of the thermochromic ink and thermally discolors the handwriting by frictional heat caused by rubbing; and a clip body 7 serving as at least one operation body. The rubbing part 10 is arranged at a rear end of the barrel 2. The clip body 7 is arranged at a portion of the barrel 2 other than the rear end.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a thermochromic writing instrument. Specifically, it relates to a thermochromic writing instrument that houses thermochromic ink inside a writing body, provides a pen tip at the front end of the writing body through which the thermochromic ink can be ejected, houses the writing body movably in the axial cylinder in the front-rear direction, and is configured such that the pen tip of the writing body can protrude from and retract into the front end hole of the axial cylinder.

Background Art

[0002] Patent Document 1 discloses a thermochromic writing instrument that houses a writing body movably in the axial cylinder in the front-rear direction, provides an operation part on the outer surface of the axial cylinder, and is configured such that the pen tip of the writing body can protrude from and retract into the front end hole of the axial cylinder by operating the operation part. The thermochromic ink is housed inside the writing body, a pen tip through which the thermochromic ink can be ejected is provided at the front end of the writing body, and a friction part for rubbing the handwriting of the thermochromic ink and thermochroming the handwriting with the frictional heat generated at that time is provided on the outer surface of the axial cylinder.

[0003] In Patent Document 1, when a friction part is provided on the operation part in the type where the operation part at the rear end of the axial cylinder is pressed forward, if a friction operation is performed using the friction part, the operation part may move forward due to the writing surface, and there is a possibility that a stable friction operation cannot be performed. In particular, when adopting a retracting and protruding mechanism (so-called double knock type) in which both the pen tip protruding operation and the pen tip retracting operation press the operation part forward and a friction part is provided on the operation part, the operating body may rattle in the front-rear direction in the pen tip protruding state, and there is a possibility that a stable friction operation cannot be performed.

[0004] Further, FIG. 12 of Patent Document 1 discloses a configuration in which a cylindrical operation portion is provided so as to be movable in the front-rear direction, a clip that can be clamped in a pocket or the like is provided protruding from the outer surface of the cylindrical operation portion, and a friction portion is provided on the outer surface of the rear end of the cylindrical operation portion. However, in the thermochromic writing instrument having this configuration, since the friction portion is pressed during the operation of protruding and retracting the pen tip, the friction portion may be soiled with fingerprints or the like. And when the friction portion is soiled and the handwriting of the thermochromic ink is rubbed, the writing surface (for example, paper surface) having the handwriting may be soiled.

[0005] Further, FIG. 15 of Patent Document 1 discloses a configuration in which an operation portion protrudes radially outward from the side wall of the shaft cylinder, and by pressing the operation portion forward against the biasing force in the rearward direction, the pen tip is changed from the retracted state to the protruding state (so-called multi-core type side slide type) retracting and protruding mechanism, and a configuration in which a friction portion is provided on the outer surface of the rear end of the shaft cylinder is disclosed. However, in the thermochromic writing instrument having this configuration, when changing from the pen tip protruding state to the pen tip retracted state (when releasing the pen tip protruding state), an operating body attached to another writing body must be operated. Therefore, it is necessary to provide a plurality of operating bodies (that is, a plurality of protruding portions), and the degree of freedom in the external design is reduced. Furthermore, when a clip that can be clamped in a pocket or the like is provided on the shaft cylinder, the number of protruding portions further increases, and the degree of freedom in the external design is reduced.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention solves the above-mentioned conventional problems, enables stable friction operation using a friction portion, further avoids the friction portion from being soiled with fingerprints or the like, and moreover, aims to provide a thermochromic writing instrument with an increased degree of freedom in external design.

[0008] In addition to the above, the present invention aims to provide a thermochromic writing instrument having the following operational effects. (1) The user can easily acquire the operation method, and the operation method is simple. (2) The clip body can be easily inserted into the slide hole. (3) It is possible to avoid the entire shaft cylinder becoming unnecessarily long. (4) Even when gripping near the clip body with the pen tip protruding, a stable friction operation is possible. (5) The clamping performance of the clip body is improved and the wobbling of the clip body can be prevented. (6) When changing from the pen tip protruding state to the pen tip retracted state, the impact applied to the writing body can be mitigated.

[0009] In the present invention, "front" refers to the pen tip side, and "rear" refers to the opposite side. In the present invention, the "pen tip retracted state" means a state in which the pen tip is retracted into the shaft cylinder, and the "pen tip protruding state" means a state in which the pen tip protrudes outside the front end of the shaft cylinder.

Means for Solving the Problems

[0010] In order to achieve the above object, the thermochromic writing instrument of the present invention houses a writing body containing thermochromic ink in a shaft cylinder, operates an operating body provided on the shaft cylinder to move the writing body in the front-rear direction, and is configured such that the pen tip of the writing body can protrude from and retract into the tip of the writing instrument. The thermochromic writing instrument is provided with a friction part that can thermochromically change the handwriting of the thermochromic ink by rubbing the handwriting and using the frictional heat generated at that time, and a clip body as at least one of the operating bodies. The friction part is provided at the rear end of the shaft cylinder, and the clip body is provided at a part of the shaft cylinder other than the rear end.

[0011] According to the above configuration, by providing the friction part independently of the clip body (operating body) at the rear end of the shaft cylinder, the friction part does not move backward during the friction operation, and the friction operation using the friction part becomes stable. In addition, since it is not necessary to touch the friction part when operating the pen tip to protrude and retract, it is possible to avoid the friction part being soiled by fingerprints or the like.

[0012] Preferably, in the thermochromic writing instrument of the present invention described above, only the single clip body is provided as the operating body, and by operating the single clip body, the pen tip of the writing body can be brought into a protruding state and a retracted state.

[0013] According to the above configuration, the operation of protruding and retracting the pen tip can be performed with a single clip body, and there is no need to provide a plurality of operating bodies (i.e., a plurality of protruding portions) on the shaft tube. Furthermore, since the clip body as the operating body also serves as a clip that can be clamped to a pocket or the like, the protruding portion as the operating body can be eliminated in terms of appearance, increasing the degree of freedom in the design of the thermochromic writing instrument and obtaining a smart appearance.

[0014] In the thermochromic writing instrument of the present invention described above, the shaft tube may be configured to be composed of a plurality of parts that can be connected to each other. In this case, the portion including the rear end of the shaft tube may be composed of a rear shaft as the part, and the friction portion may be provided at the rear end portion of the rear shaft. That is, the shaft tube constituting the present thermochromic writing instrument may be a single cylindrical body, or may be a single cylindrical body formed by connecting a plurality of parts to each other.

[0015] Preferably, in the thermochromic writing instrument of the present invention described above, a slide hole extending in the front-rear direction is provided on the side wall of the shaft tube, and a retracting mechanism is provided in which the pen tip of the writing body is changed from a retracted state to a protruding state by sliding the clip body disposed in the slide hole forward.

[0016] According to the above configuration, by sliding the clip body forward, the pen tip can be brought into a protruding state and a retracted state (a so-called double-knock type retracting mechanism), the operation method is simple, and the user can easily acquire the operation method.

[0017] Preferably, in the thermochromic writing instrument of the present invention described above, the shaft cylinder is composed of two or more parts that can be connected to each other. On each side wall of the two parts constituting the shaft cylinder, a first or second long hole with an open front end or rear end and extending in the front-rear direction is provided respectively. When the two parts are connected, the first and second long holes communicate with each other to form the slide hole.

[0018] According to the above configuration, for example, when a slide hole is formed by a first long hole opened rearward and a second long hole opened forward, when connecting the two parts constituting the shaft cylinder (that is, when forming the slide hole), the attachment part of the clip body can be easily inserted into the slide hole through the open ends of the first and second long holes, and it becomes possible to efficiently assemble the clip body and the shaft cylinder.

[0019] Preferably, in the thermochromic writing instrument of the present invention described above, each side wall of the two parts constituting the shaft cylinder is connected so as to overlap each other in the radial direction, and the first and second long holes communicate with each other in a state of overlapping each other in the radial direction to form the slide hole.

[0020] According to the above configuration, by communicating the first and second long holes in a state of overlapping each other in the radial direction, it is possible to avoid the entire shaft cylinder becoming unnecessarily long. That is, the overlapping portion of the first and second long holes does not affect the total length of the slide hole. Regarding the configuration of "overlapping in the radial direction", specific examples will be given and described in detail later.

[0021] More preferably, in the thermochromic writing instrument of the present invention described above, the step of inserting the base of the clip body into the first long hole provided in one of the parts constituting the shaft cylinder, and while inserting the base of the clip body into the second long hole provided in the other part constituting the shaft cylinder, connecting the other part to the one part, and communicating the second long hole with the first long hole to form the slide hole, and then assembling the clip body into the slide hole.

[0022] According to the above configuration, in addition to being able to easily insert the clip body into the slide hole, by using the base of the clip body inserted into the first long hole as a guide, the alignment of the first and second long holes and the connection of one part and another part can be easily performed.

[0023] Preferably, in the thermochromic writing instrument of the present invention described above, a cam mechanism as the projecting and retracting mechanism is provided in the shaft cylinder. The cam mechanism includes a cam portion and a protrusion that can be engaged at different positions in the front-rear direction alternately. By sliding the clip body forward, the cam portion and the protrusion are engaged at different positions in the front-rear direction alternately, and the pen tip of the writing body is configured to be alternately in a protruding state or a retracted state.

[0024] More preferably, as the projecting and retracting mechanism, a plurality of cam teeth and cam grooves extending in the front-rear direction and arranged alternately along the circumferential direction, a rotating member rotatably arranged behind the writing body and having a plurality of ridges that can be alternately engaged with the cam teeth or the cam grooves, a plurality of other cam teeth provided on the clip body for rotating the rotating member, and an elastic body for biasing the writing body backward are provided in the shaft cylinder. Against the biasing force of the elastic body, by sliding the clip body forward, the ridges are alternately engaged with the cam teeth or the cam grooves, and the pen tip of the writing body may be alternately in a protruding state or a retracted state.

[0025] According to such a configuration, a double-knock type projecting and retracting mechanism that can make the pen tip protrude and retract by simply sliding the clip body forward by using the cam mechanism can be configured, the operation method of this thermochromic writing instrument becomes extremely simple, and the user can easily acquire the operation method.

[0026] Preferably, in the projecting and retracting mechanism of the above-described thermochromic writing instrument, the clip body has a shaft portion that is accommodated in the shaft cylinder and extends in the front-rear direction, and the shaft portion and the rotating member are configured to be locked to each other in a state of having play in the front-rear direction.

[0027] According to such a configuration, the shaft portion of the clip body and the rotating member are locked in a state having play in the front-rear direction, so that in the protruding state of the pen tip (that is, when the cam teeth and the protrusions are engaged in the front), the backward movement of the clip body that has moved forward of the slide hole is blocked. As a result, when performing a friction operation in the protruding state of the pen tip, even if the vicinity of the clip body is gripped, the clip body does not move inadvertently, and a stable friction operation becomes possible.

[0028] Preferably, in the protruding and retracting mechanism of the present thermochromic writing instrument described above, a guide groove extending in the front-rear direction is formed on the outer surface of the shaft cylinder in front of the slide hole, a ball portion is provided protruding on the inner surface of the front portion of the clip body, and the ball portion slides in the guide groove in the front-rear direction as the clip body moves in the front-rear direction.

[0029] According to the above configuration, when the clip body is slid, the ball portion slides along the guide groove to guide the clip body in the front-rear direction, so that it is possible to prevent the clip body from wobbling in the lateral direction (circumferential direction). Further, when a clamped object such as a pocket of clothing or a notebook is clamped by the clip body, the clamped object is sandwiched between the ball portion and the guide groove, so that the clamping performance of the clip body is improved.

[0030] Preferably, in the protruding and retracting mechanism of the present thermochromic writing instrument described above, the friction portion is made of an elastic material, and a part of the friction portion abuts on the clip body in the pen tip retracted state.

[0031] According to the above configuration, when the pen tip is changed from the protruding state to the pen tip retracted state, the clip body that has moved rearward of the slide groove abuts on the friction portion made of an elastic material, so that the impact applied to the writing body at this time can be alleviated. As a result, it is possible to prevent the backflow of ink in the writing body and the entry of air from the pen tip.

[0032] In the appearance and disappearance mechanism of the above-described thermochromic writing instrument, the friction portion is made of an elastic material and is fixed to the rear end of the shaft cylinder or the rear end portion of the rear shaft by press-fitting, engagement, screwing, fitting, adhesion, two-color molding, or the entire shaft cylinder or the entire rear shaft is formed of an elastic material as the friction portion.

[0033] According to the above configuration, the friction portion can be fixed to the rear end of the shaft cylinder sufficiently firmly, and during the friction operation, the friction portion does not move backward or fall off, and the friction operation using the friction portion becomes stable.

[0034] Hereinafter, more specific embodiments <1> to <7> of the present invention described above will be described with reference to the reference numerals in FIGS. 1 to 35.

[0035] <1>The thermochromic writing instrument 1 according to the first embodiment accommodates thermochromic ink inside the writing body 9, provides a pen tip 91 at the front end of the writing body 9 through which the thermochromic ink can be discharged, and accommodates the writing body 9 in the shaft cylinder 2 so as to be movable in the front-rear direction in a state of being biased rearward. The pen tip 91 of the writing body 9 is configured to be able to appear and disappear from the front end hole 31 of the shaft cylinder 2. A slide hole 21 extending in the front-rear direction is provided in the side wall of the shaft cylinder 2, a clip body 7 protrudes radially outward from the slide hole 21, and the clip body 7 is configured to be movable in the front-rear direction along the slide hole 21. By sliding the clip body 7 forward from the pen tip retracted state, the pen tip 91 is brought into a protruding state from the front end hole 31 of the shaft cylinder 2, and by operating the clip body 7 from the pen tip protruding state, the pen tip 91 is brought into a retracted state. It is provided with an appearance and disappearance mechanism, and a friction portion 10 capable of thermochromically changing the handwriting of the thermochromic ink by rubbing the handwriting of the thermochromic ink and the frictional heat generated at that time is provided at the rear end of the shaft cylinder 2.

[0036] In the thermochromic writing instrument 1 according to the first embodiment, since the friction portion 10 is provided at the rear end of the shaft cylinder 2, the backward movement of the friction portion 10 is blocked during the friction operation, so that a stable friction operation can be performed using the friction portion 10. Further, in the thermochromic writing instrument 1 according to the first embodiment, an operation portion for operating the protrusion and retraction of the pen tip is provided on the clip body 7, and by separating the friction portion 10 from the clip body 7 (operation portion), when the pen tip 91 protrudes and retracts, the clip body 7 is operated and the friction portion 10 is not operated, so that the friction portion 10 can be prevented from being soiled by fingerprints or the like. Further, in the thermochromic writing instrument 1 according to the first embodiment, although the clip body 7 is provided on the outer surface of the shaft cylinder 2, compared with the conventional multi-core type side-slide type thermochromic writing instrument, there are fewer protruding portions, the degree of freedom in the external design is increased, and a smart appearance can be obtained.

[0037] In the present invention, the clip body 7 is capable of being clamped by a clamped object such as a pocket of clothing or a notebook between the clip body 7 and the outer surface of the shaft cylinder 2. In the present invention, the friction portion 10 only needs to be configured to fix the friction portion 10 to the rear end of the shaft cylinder 2 at least during the friction operation. For example, the friction portion 10 may be configured to protrude and retract from the rear end of the shaft cylinder 2 by an operation other than the operation of protruding and retracting the pen tip. In the present invention, operating the clip body 7 from the pen tip protruding state means an operation of releasing the pen tip protruding state. For example, sliding the clip body 7 forward, pressing the clip body 7 radially inward, or rotating the clip body 7 can be cited. In the present invention, the friction operation time means the time when the friction operation is performed using the friction portion 10. During the friction operation, it may be either the pen tip protruding state or the pen tip retracted state.

[0038] <2>The thermochromic writing instrument 1 according to the second embodiment is the writing instrument 1 of the first invention, wherein the protruding and retracting mechanism is a side slide type protruding and retracting mechanism using a rotary cam mechanism, including a cam portion 41 formed on the inner surface of the shaft cylinder 2, a rotating member 6 that engages with the cam portion 41 and abuts against the rear end of the writing body 9, the clip body 7 provided with cam teeth 73a and 74a that engage with the rotating member 6, and an elastic body 8 that is housed in the shaft cylinder 2 and biases the writing body 9 rearward. Both the pen tip protruding operation and the pen tip retracting operation are configured to be of a type that slides the clip body 7 forward.

[0039] In the thermochromic writing instrument 1 according to the second embodiment, the protruding and retracting mechanism is a side slide type protruding and retracting mechanism using a rotary cam mechanism. Since both the pen tip protruding operation and the pen tip retracting operation are of a type that slides the clip body 7 forward (so-called double knock type protruding and retracting mechanism), the operation method is simple and the user can easily acquire the operation method.

[0040] <3>The thermochromic writing instrument 1 according to the third embodiment is the thermochromic writing instrument 1 of the first or second invention, wherein the shaft cylinder 2 is composed of a front shaft 3, an intermediate shaft 4 connected to the rear end portion of the front shaft 3, and a rear shaft 5 connected to the rear end portion of the intermediate shaft 4. A front end hole 31 through which the pen tip 91 can protrude and retract is provided at the front end of the front shaft 3. A cam portion 41 is provided on the inner surface of the intermediate shaft 4. A first long hole 44 that is open rearward and extends in the front-rear direction is provided at the rear end portion of the intermediate shaft 4. A second long hole 51 that is open forward and extends in the front-rear direction is provided at the front end portion of the rear shaft 5. The rear end portion of the intermediate shaft 4 and the front end portion of the rear shaft 5 are connected such that the first long hole 44 and the second long hole 51 communicate with each other. The slide hole 21 is formed in the side wall of the shaft cylinder 2 by the first long hole 44 and the second long hole 51. A friction portion 10 is fixed to the outer surface of the rear end of the rear shaft 5.

[0041] The thermochromic writing instrument 1 according to the third embodiment forms a slide hole 21 by a first long hole 44 that is open rearward and a second long hole 51 that is open forward. When connecting the intermediate shaft 4 and the rear shaft 5 (that is, when forming the slide hole 21), the clip body 7 can be inserted into the first long hole 44 and the second long hole 51, the clip body 7 can be easily inserted into the slide hole 21, and easy insertion and assembly of the clip body 7 and the shaft cylinder 2 becomes possible.

[0042] <4>The thermochromic writing instrument 1 according to the fourth embodiment is the thermochromic writing instrument 1 of the third invention, in which the side wall of the intermediate shaft 4 and the side wall of the rear shaft 5 are connected so as to overlap each other in the radial direction, and the first long hole 44 and the second long hole 51 are configured to communicate with each other in the radial direction.

[0043] The thermochromic writing instrument 1 according to the fourth embodiment connects the side wall of the intermediate shaft 4 and the side wall of the rear shaft 5 so as to overlap each other in the radial direction and communicates the first long hole 44 and the second long hole 51 in the radial direction, thereby avoiding the entire shaft cylinder 2 becoming unnecessarily long. In the present invention, connecting the side wall of the intermediate shaft 4 and the side wall of the rear shaft 5 so as to overlap each other in the radial direction means, for example, a configuration in which the outer surface of the side wall of the intermediate shaft 4 and the inner surface of the side wall of the rear shaft 5 are connected (for example, fitted or screwed) so as to overlap each other in the radial direction, or a configuration in which the inner surface of the side wall of the intermediate shaft 4 and the outer surface of the side wall of the rear shaft 5 are connected (for example, fitted or screwed) so as to overlap each other in the radial direction. The configuration of connecting the side wall of the intermediate shaft 4 and the side wall of the rear shaft 5 so as to overlap each other in the radial direction may be a configuration in which at least a part of the side wall of the intermediate shaft 4 and a part of the side wall of the rear shaft 5 are connected so as to overlap each other in the radial direction.

[0044] <5>The thermochromic writing instrument 1 according to the fifth embodiment is the thermochromic writing instrument 1 of the second, third, or fourth invention, in which the clip body 7 has a shaft portion 73 that is housed in the shaft cylinder 2 and extends in the front-rear direction, and the shaft portion 73 and the rotating member 6 are configured to be rotatable with respect to each other and locked in the front-rear direction while having play in the front-rear direction.

[0045] In the thermochromic writing instrument 1 according to the fifth embodiment, the clip body 7 has a shaft portion 73 that is accommodated in the shaft tube 2 and extends in the front-rear direction, and the shaft portion 73 and the rotating member 6 are locked in the front-rear direction in a state where they can rotate relative to each other and have play in the front-rear direction. As a result, in the state where the pen tip protrudes, the rotating member 6 is locked to the cam teeth 41a of the cam portion 41, the rearward movement of the rotating member 6 is blocked, and the inadvertent front-rear movement of the clip body 7 is suppressed. As a result, even when the vicinity of the clip body 7 is gripped in the state where the pen tip protrudes, a stable friction operation becomes possible.

[0046] <6>In the thermochromic writing instrument 1 according to the sixth embodiment, in the thermochromic writing instrument 1 according to any one of the first to fifth inventions, a guide groove 48 extending in the front-rear direction is formed on the outer surface of the shaft tube 2 in front of the slide hole 21, a ball portion 71a is provided protruding from the inner surface of the front portion of the clip body 7, and the ball portion 71a slides in the front-rear direction in the guide groove 48 as the clip body 7 moves in the front-rear direction.

[0047] In the thermochromic writing instrument 1 according to the sixth embodiment, a guide groove 48 extending in the front-rear direction is formed on the outer surface of the shaft tube 2 in front of the slide hole 21, a ball portion 71a is provided protruding from the inner surface of the front portion of the clip body 7, and the ball portion 71a slides in the front-rear direction in the guide groove 48 as the clip body 7 moves in the front-rear direction. As a result, the clamping performance of the clip body is improved and the lateral (circumferential) wobbling of the clip body 7 can be prevented.

[0048] <7>In the thermochromic writing instrument 1 according to the seventh embodiment, in the thermochromic writing instrument 1 according to any one of the first to sixth inventions, the friction portion 10 is made of an elastic material, and a part of the friction portion 10 abuts against the clip body 7 in the state where the pen tip is retracted.

[0049] The thermochromic writing instrument 1 according to the seventh embodiment has a friction portion 10 made of an elastic material, and a part of the friction portion 10 abuts against the clip body 7 in a state where the pen tip is immersed. When changing from the pen tip protruding state to the pen tip immersed state, the writing body 9 and the clip body 7 move backward due to the biasing force of the elastic body 8, and the clip body 7 comes into contact with the friction portion 10 made of an elastic material. Therefore, the impact applied to the writing body 9 at that time can be mitigated. As a result, backflow of the ink in the writing body 9 and entry of air from the pen tip 91 can be prevented.

Advantages of the Invention

[0050] The thermochromic writing instrument of the present invention enables stable friction operation using a friction portion, and further, it is possible to avoid the friction portion from being soiled by fingerprints or the like. Moreover, the degree of freedom in the external design increases, and a smart appearance can be obtained.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0052] <The First Embodiment> FIGS. 1 and 9 show embodiments of the present invention. The thermochromic writing instrument 1 of this embodiment includes a shaft cylinder 2, a writing body 9 housed in the shaft cylinder 2, and a projecting and retracting mechanism for making the pen tip of the writing body 9 project and retract freely from the front end hole 31 of the shaft cylinder 2.

[0053] ·Writing body The writing body 9 includes a pen tip 91, an ink storage tube 92 in which the pen tip 91 is press-fitted and fixed to the front end opening, thermochromic ink filled in the ink storage tube 92, and a follower (for example, a high-viscosity fluid) filled at the rear end of the thermochromic ink and advancing as the thermochromic ink is consumed.

[0054] The pen tip 91 may be composed of, for example, only a metal ball pen tip that rotatably holds a ball at the front end, or a pen tip holder made of synthetic resin that holds the outer surface of the rear part of the ball pen tip. Further, a tail plug provided with a ventilation hole through which the ink storage tube 92 and the outside communicate is attached to the rear end opening of the ink storage tube 92. Inside the pen tip 91, a spring for pressing the ball at the front end forward is housed therein. The spring has a configuration in which a rod portion is provided at the front end 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 closely attached to the inner surface of the inward front edge at the front end of the ball pen tip by the forward biasing of the spring, and the leakage of ink from the front end of the pen tip 91 and the evaporation of ink can be prevented.

[0055] ·Shaft cylinder The shaft cylinder 2 is composed of a tapered cylindrical front shaft 3, a cylindrical intermediate shaft 4 connected to the rear end of the front shaft 3, and a cylindrical rear shaft 5 connected to the rear end of the intermediate shaft 4.

[0056] The front shaft 3 is shown in FIG. 5. The front shaft 3 is composed of a tapered cylindrical main body 3a made of a molded body of synthetic resin (for example, polycarbonate resin) and a gripping portion 3b made of an elastic material provided on the outer surface of the main body 3a. The gripping portion 3b is provided by two-color molding or attachment. The rear end portion of the front shaft 3 has a reduced diameter, and an external thread portion 32 is formed on its outer surface. A front end hole 31 is provided through the front end of the front shaft 3 in the front-rear direction.

[0057] The intermediate shaft 4 is shown in FIG. 6. The intermediate shaft 4 is composed of a molded body of cylindrical synthetic resin (for example, polycarbonate resin). An internal thread portion 46 is formed on the inner surface of the front end portion of the intermediate shaft 4. The external thread portion 32 of the front shaft 3 can be screwed into the internal thread portion 46. A reduced diameter portion 43 is integrally formed at the rear end portion of the intermediate shaft 4. A first long hole 44 extending in the front-rear direction, with its front end closed and rear end open, is formed in the reduced diameter portion 43. Further, an outward protrusion 45 is integrally formed on the outer surface of the reduced diameter portion 43. A stepped portion 42 is integrally formed on the inner surface of the intermediate shaft 4 in front of the reduced diameter portion 43. A cam portion 41 is integrally formed on the inner surface of the intermediate shaft 4 (the inner surface of the intermediate shaft 4 in front of the first long hole 44 of the intermediate shaft 4) in front of the stepped portion 42. Also, the stepped portion 42 is integrally formed on the inner surface of the intermediate shaft 4 behind the cam portion 41 and in front of the first long hole 44 (that is, between the cam portion 41 and the first long hole 44). Also, a locking protrusion 47 is integrally formed on the outer surface of the intermediate shaft 4. In a state where the pen tip is inserted, an object to be clamped such as a pocket can be clamped between the locking protrusion 47 and the ball portion 71a of the clip body 7.

[0058] The rear shaft 5 is shown in Fig. 7. The rear shaft 5 is formed of a molded body of a cylindrical synthetic resin (for example, polycarbonate resin). A second long hole 51 extending in the front-rear direction, which is open at the front end and closed at the rear end, is formed in the side wall of the front end portion of the rear shaft 5. Further, a mounting hole 52 is formed through the rear end of the rear shaft 5 in the front-rear direction. A friction portion 10 made of an elastic material is press-fitted into the mounting hole 52. Thereby, the friction portion 10 is fixed to the outer surface of the rear end of the rear shaft 5. Further, an inward projection 53 is integrally formed on the inner surface of the rear shaft 5. The width dimension of the second long hole 51 is set to be equal to the width dimension of the first long hole 44, whereby the clip body 7 can smoothly move in the front-rear direction along the slide hole 21.

[0059] The clip body 7 is shown in Fig. 8. The clip body 7 includes a clip main body 71 extending in the front-rear direction, a base portion 72 integrally connected to the rear portion of the clip main body 71, and a shaft portion 73 integrally connected to the base portion 72 and extending forward from the base portion 72. The clip body 7 is obtained by a molded body of a synthetic resin (for example, polycarbonate resin). A ball portion 71a projects from the back surface of the clip main body 71. A cam tooth 73a is integrally formed at the front end of the shaft portion 73.

[0060] ·Assembly of the clip body The assembly of the clip body 7 will be described. From the rear end opening of the first long hole 44 of the intermediate shaft 4, the base 72 of the clip body 7 is inserted into the first long hole 44, and the shaft portion 73 of the clip body 7 is inserted into the intermediate shaft 4. Thereafter, the inner surface of the rear shaft 5 is fitted to the outer surface of the reduced diameter portion 43 of the intermediate shaft 4 so that the first long hole 44 of the intermediate shaft 4 and the second long hole 51 of the rear shaft 5 communicate in the radial direction (overlap in the radial direction), and the base 72 of the clip body 7 is inserted into the second long hole 51 from the front end opening of the second long hole 51. Thereby, the intermediate shaft 4 and the rear shaft 5 are connected, and the slide hole 21 extending in the front-rear direction is formed by the first long hole 44 and the second long hole 51, and the clip body 7 (a part of the clip main body 71 and the base 72) protrudes radially outward from the slide hole 21, and the clip body 7 is configured to be slidable in the front-rear direction (slidable in the front-rear direction) along the slide hole 21. At this time, the outward protrusion 45 on the outer surface of the reduced diameter portion 43 of the intermediate shaft 4 and the inward protrusion 53 on the inner surface of the rear shaft 5 are engaged with each other by getting over.

[0061] By connecting the rear shaft 5 to which the friction portion 10 is fixed to the rear end portion of the intermediate shaft 4, the friction portion 10 is always fixed to the rear end of the shaft cylinder 2. Further, the front shaft 3 and the intermediate shaft 4 are detachably connected by screwing, whereby the writing body 9 can be replaced.

[0062] ·Protrusion and retraction mechanism The protrusion and retraction mechanism is a side slide type protrusion and retraction mechanism using a rotary cam mechanism. The protrusion and retraction mechanism includes a cam portion 41 formed on the inner surface of the intermediate shaft 4, a rotating member 6 that engages with the cam portion 41 and abuts against the rear end of the writing body 9, a clip body 7 that engages with the rotating member 6 and protrudes radially outward from the slide hole 21, and an elastic body 8 (for example, a compression coil spring) that is housed in the shaft cylinder 2 and biases the writing body 9 rearward. The protrusion and retraction mechanism of the present embodiment is a double knock type in which both the pen tip protrusion operation and the pen tip retraction operation slide the clip body 7 forward. The rotating member 6 is obtained by a molded body of synthetic resin (for example, polyacetal resin).

[0063] The cam portion 41 includes a plurality of serrated cam teeth 41a protruding forward, and a plurality of cam grooves 41b formed between the cam teeth 41a and extending in the front-rear direction. The rotating member 6 includes a plurality of (for example, four) ridges 61 extending in the front-rear direction on its outer surface, and the ridges 61 are engaged with the cam teeth 41a of the cam portion 41 and the cam grooves 41b of the cam portion 41. At the front end of the shaft portion 73 of the clip body 7, a cam tooth 73a engaged with the rear end of the ridge 61 of the rotating member 6 is integrally formed.

[0064] ·Protrusion and retraction of the pen tip When the clip body 7 is slid forward from the state where the pen tip is retracted, against the biasing force of the elastic body 8 acting rearward, the rotating member 6 is pressed forward by the cam tooth 73a of the shaft portion 73 of the clip body 7. As the ridge 61 of the rotating member 6 moves forward along the cam groove 41b, the rotating member 6 presses the rear end of the writing body 9 forward, and the pen tip 91 protrudes outside the front end hole 31. At this time, the rotating member 6 rotates by a certain angle with respect to the cam portion 41 due to the contact between the cam tooth 73a of the shaft portion 73 and the ridge 61 of the rotating member 6. Thereby, the ridge 61 of the rotating member 6 is engaged with the cam tooth 41a of the cam portion 41, and the state where the pen tip protrudes is maintained.

[0065] When the clip body 7 is slid forward from the state where the pen tip protrudes, the shaft portion 73 of the clip body 7 presses the rotating member 6 forward, and the rotating member 6 rotates by a certain angle with respect to the cam portion 41 due to the contact between the cam tooth 73a of the shaft portion 73 and the ridge 61 of the rotating member 6. Thereby, the engagement state between the ridge 61 and the cam tooth 41a of the cam portion 41 is released, and the ridge 61 moves rearward along the cam groove 41b of the cam portion 41 due to the rearward biasing force of the elastic body 8. As the rotating member 6 moves rearward, the writing body 9 moves rearward, and the pen tip retracts.

[0066] The friction portion 10 is not interlocked with the forward and backward movement of the clip body 7 and is fixed to the outer surface of the rear end of the rear shaft 5 (shaft cylinder 2). The friction portion 10 is provided independently of the clip body 7.

[0067] ·Another example of the clip body Fig. 9 shows another embodiment of the clip body 7. The difference between the clip body 7 of Fig. 8 in this embodiment and that in the previous embodiments is that a cylindrical body 74 having cam teeth 74a is attached to the shaft portion 73 of the clip body 7. Since the other configurations, operations, and effects are the same as those of the embodiments shown in Figs. 1 to 8, the description thereof is omitted. The cylindrical body 74 is obtained by a molded article of a synthetic resin (for example, polyacetal resin).

[0068] ·Friction portion In this embodiment, the elastic material constituting the friction portion 10 is preferably a synthetic resin (rubber, elastomer) having elasticity. For example, silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butadiene-styrene copolymer), fluororesin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM), etc. may be mentioned. The elastic synthetic resin constituting the friction portion 10 is preferably made of a low-wear elastic material that hardly generates wear debris (shavings) during friction, rather than a high-wear elastic material (for example, sandpaper, etc.). Further, the friction portion 10 may be provided at least on the outer surface of the rear end portion of the shaft cylinder 2. For example, a configuration in which the friction portion 10 made of an elastic material is press-fitted, engaged, screwed, fitted, adhered, two-color molded, etc. to 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 5, or a configuration in which the entire shaft cylinder 2 or the entire rear shaft 5 is integrally formed of an elastic material may be mentioned.

[0069] ·Thermochromic ink In this embodiment, the thermochromic ink is preferably a reversible thermochromic ink. The reversible thermochromic ink can be configured by using, alone or in combination, various types such as a heat-decoloring type that decolors by heating from the colored state, a color memory retention type that mutually changes the colored state or the decolored state and stores and retains them in a specific temperature range, or a heat-coloring type that colors by heating from the decolored state and returns to the decolored state by cooling from the colored state.

[0070] In addition, the coloring material contained in the reversible thermochromic ink is preferably a reversible thermochromic pigment in which a microcapsule contains a reversible thermochromic composition containing at least the essential three components of (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reaction medium that determines the color-forming temperature of both of them, which are known in the art.

[0071] In the present embodiment, as shown in FIG. 10, the shape of the curve plotting the change in coloring density due to temperature change changes along different paths when the temperature is increased from the low-temperature side to the discoloration temperature range and when it is decreased from the high-temperature side to the discoloration temperature range, and the coloring state in the low-temperature range below the complete coloring temperature (t1) or the decoloring state in the high-temperature range above the complete decoloring temperature (t4) can be stored and retained in a specific temperature range (temperature range between t2 and t3 (substantially two-phase holding temperature range)). A color memory-retaining type thermochromic ink is preferably applied. In FIG. 10, ΔH indicates the temperature width (i.e., the hysteresis width) indicating the degree of hysteresis. When the value of ΔH is small, only one of the two states before and after discoloration can exist. When the value of ΔH is large, it becomes easier to retain each state before and after discoloration.

[0072] In the present embodiment, the discoloration temperature due to the frictional heat of the frictional portion 10 of the thermochromic ink is set to 25°C to 95°C (preferably 36°C to 95°C). That is, in the present embodiment, it is effective to set the high-temperature side discoloration point [complete decoloring temperature (t4)] in the range of 25°C to 95°C (preferably 36°C to 90°C) and the low-temperature side discoloration point [complete coloring temperature (t1)] in the range of -30°C to +20°C (preferably -30°C to +10°C). Thereby, it is possible to effectively function to retain the color presented in the normal state (daily living temperature range), and the handwriting with the reversible thermochromic ink can be easily discolored by the frictional heat of the frictional portion 10.

[0073] In the thermochromic writing instrument 1 of the present embodiment, since the friction portion 10 is fixed to the outer surface of the rear end of the shaft cylinder 2, the rearward movement of the friction portion 10 is blocked during the friction operation, so that a stable friction operation can be performed using the friction portion 10. Further, in the thermochromic writing instrument 1 of the present embodiment, an operation portion for operating the protrusion and retraction of the pen tip is provided on the clip body 7, and since the friction portion 10 is made independent from the clip body 7 (operation portion), when the pen tip 91 protrudes and retracts, the clip body 7 is operated and the friction portion 10 is not operated, so that the friction portion 10 can be prevented from being soiled by hand dirt or the like. Further, in the thermochromic writing instrument 1 of the present embodiment, although the clip body 7 is provided on the outer surface of the shaft cylinder 2, compared with the conventional multi-core type side-slide type thermochromic writing instrument, there are fewer protruding portions, the degree of freedom in the external design is increased, and a smart external appearance can be obtained.

[0074] In the thermochromic writing instrument 1 of the present embodiment, the protruding / retracting mechanism is a side-slide type protruding / retracting mechanism using a rotary cam mechanism, and both the pen tip protruding operation and the pen tip retracting operation are of the type in which the clip body 7 is slid forward (so-called double knock type protruding / retracting mechanism), so the operation method is simple and the user can easily acquire the operation method.

[0075] In the thermochromic writing instrument 1 of the present embodiment, the slide hole 21 is formed by the first long hole 44 opened rearward and the second long hole 51 opened forward. When connecting the intermediate shaft 4 and the rear shaft 5 (that is, when forming the slide hole 21), the clip body 7 can be inserted into the first long hole 44 and the second long hole 51, the clip body 7 can be easily inserted into the slide hole 21, and easy insertion and assembly of the clip body 7 and the shaft cylinder 2 can be achieved.

[0076] In the thermochromic writing instrument 1 of the present embodiment, the side wall of the intermediate shaft 4 and the side wall of the rear shaft 5 are connected so as to overlap in the radial direction, and the first long hole 44 and the second long hole 51 are communicated in the radial direction, so that it is possible to avoid the entire shaft cylinder 2 becoming unnecessarily long.

[0077] The thermochromic writing instrument 1 of this embodiment has a friction portion 10 made of an elastic material, and a part of the friction portion 10 abuts on the clip body 7 in a state where the pen tip is immersed. Thus, when changing from the pen tip protruding state to the pen tip immersed state, the writing body 9 and the clip body 7 move rearward due to the rearward biasing of the elastic body 8, and the clip body 7 and the friction portion 10 made of an elastic material abut on each other. Therefore, the impact applied to the writing body 9 at that time can be alleviated. As a result, backflow of the ink in the writing body 9 and entry of air from the pen tip 91 can be prevented.

[0078] <Second Embodiment> The second embodiment of the present invention is shown in FIGS. 11 to 35. The thermochromic writing instrument 1 of this embodiment includes a shaft cylinder 2, a writing body 9 housed in the shaft cylinder 2, and a projecting and retracting mechanism that allows the pen tip 91 of the writing body 9 to project and retract from the front end hole 31 of the shaft cylinder 2.

[0079] ·Writing body The writing body 9 includes a pen tip 91, an ink storage tube 92 in which the pen tip 91 is press-fitted and fixed to the front end opening, a thermochromic ink 93 filled in the ink storage tube 92, and a follower 94 (for example, a high-viscosity fluid) filled at the rear end of the thermochromic ink 93 and advancing as the thermochromic ink 93 is consumed.

[0080] The pen tip 91 may be composed of, for example, only a metal ball pen tip that rotatably holds a ball at the front end, or a pen tip holder made of synthetic resin that holds the outer surface of the rear portion of the ball pen tip. Further, a tail plug 95 having a vent hole through which the ink storage tube 92 and the outside communicate is attached to the rear end opening of the ink storage tube 92. Inside the pen tip 91, a spring that presses the ball at the front end forward is housed. The spring has a configuration in which a rod portion is provided at the front end of a compression coil spring, and the front end of the rod portion is in contact with the rear surface of the ball. During non-writing, due to the forward biasing of the spring, the ball is in close contact with the inner surface of the inward front edge portion at the front end of the ball pen tip, and leakage of ink from the front end of the pen tip 91 and evaporation of the ink can be prevented.

[0081] ·Shaft cylinder The shaft cylinder 2 is composed of a tapered cylindrical front shaft 3, a cylindrical intermediate shaft 4 connected to the rear end portion of the front shaft 3, and a cylindrical rear shaft 5 connected to the rear end portion of the intermediate shaft 4.

[0082] The front shaft 3 is shown in Fig. 18. The front shaft 3 is composed of a tapered cylindrical main body 3a made of a molded body of synthetic resin (for example, polycarbonate resin), and a gripping portion 3b made of an elastic material provided on the outer surface of the main body 3a. The gripping portion 3b is provided by two-color molding or attachment to the outer surface of the main body 3a. The rear end portion of the front shaft 3 has a reduced diameter, and a male screw portion 32 is formed on its outer surface. A front end hole 31 is formed through the front end of the front shaft 3 in the front-rear direction.

[0083] The intermediate shaft 4 is shown in Figs. 19 to 21. The intermediate shaft 4 is composed of a molded body of cylindrical synthetic resin (for example, polycarbonate resin). A female screw portion 46 is formed on the inner surface of the front end portion of the intermediate shaft 4. The male screw portion 32 of the front shaft 3 can be screwed into the female screw portion 46. A reduced diameter portion 43 is integrally formed at the rear end portion of the intermediate shaft 4. A first elongated hole 44 extending in the front-rear direction, with its front end closed and its rear end open, is formed in the side wall of the rear end portion of the intermediate shaft 4. Further, an outward protrusion 45 is integrally formed on the outer surface of the reduced diameter portion 43. A stepped portion 42 is integrally formed on the inner surface of the intermediate shaft 4 in front of the reduced diameter portion 43. A cam portion 41 is integrally formed on the inner surface of the intermediate shaft 4 in front of the stepped portion 42. Also, the front end of the first elongated hole 44 is located slightly in front of the stepped portion (i.e., the rear end of the cam portion 41) and behind the cam teeth 41a of the cam portion 41. Further, a guide groove 48 extending in the front-rear direction is formed on the outer surface of the intermediate shaft 4 in front of the first elongated hole 44. The ball portion 71a of the clip body 7 is constantly engaged with the guide groove 48, and as the clip body 7 moves in the front-rear direction, the ball portion 71a of the clip body 7 can move in the front-rear direction along the guide groove 48. The guide groove 48 and the ball portion 71a firmly clamp an object to be clamped, such as a pocket.

[0084] The rear shaft 5 is shown in FIGS. 22 to 25. The rear shaft 5 is made of a molded body of a cylindrical synthetic resin (for example, polycarbonate resin). A second long hole 51 extending in the front-rear direction, with its front end open and rear end closed, is formed in the side wall of the front end portion of the rear shaft 5. Further, a mounting hole 52 is formed through the rear end of the rear shaft 5 in the front-rear direction. A friction portion 10 made of an elastic material is press-fitted into the mounting hole 52. Thereby, the friction portion 10 is fixed to the outer surface of the rear end of the rear shaft 5. Further, an inward projection 53 is integrally formed on the inner surface of the rear shaft 5. The width dimension of the second long hole 51 is set equal to the width dimension of the first long hole 44, whereby the clip body 7 can smoothly move in the front-rear direction along the slide hole 21.

[0085] The clip body 7 is shown in FIG. 28. The clip body 7 includes a main portion 7a composed of a clip main body 71 extending in the front-rear direction, a base portion 72 integrally connected to the rear portion of the clip main body 71, and a shaft portion 73 integrally connected to the base portion 72 and extending forward from the base portion 72, and a cylindrical body 74 attached to the shaft portion 73. The main portion 7a of the clip body 7 is obtained by a molded body of a synthetic resin (for example, polycarbonate resin). A plate-like ball portion 71a is integrally projected on the back surface (inner surface) of the clip main body 71.

[0086] The shaft portion 73 includes a large-diameter portion 73b and a small-diameter portion 73c connected in front of the large-diameter portion 73b and having an outer diameter smaller than that of the large-diameter portion 73b. A first outward projection 73d is integrally formed on the outer surface of the large-diameter portion 73b, and a second outward projection 73e is integrally formed on the outer surface of the small-diameter portion 73c. The first outward projection 73d and the second outward projection 73e include, for example, an annular projection or a dispersed projection in which a plurality of projections are dispersed in a circumferential shape.

[0087] A rib 72a extending in the front-rear direction is formed on the outer surface of the base portion 72 or the outer surface of the shaft portion 73 of the clip body 7. The rib 72a engages with a groove 49 extending in the front-rear direction formed on the inner surface of the rear end portion of the intermediate shaft 4, and the rib 72a moves in the front-rear direction along the groove 49. Thereby, the circumferential wobbling of the clip body 7 can be suppressed.

[0088] Figures 29 to 31 show the cylindrical body 74. The cylindrical body 74 is attached to the outer surface of the shaft portion 73 of the clip body 7. At the front end of the cylindrical body 74, cam teeth 74a are formed. Inside the cylindrical body 74, an inner hole penetrates in the front-rear direction, and inward protrusions 74b are integrally formed on the inner surface of the inner hole. The cylindrical body 74 engages with and overrides the first outward protrusion 73d on the outer surface of the shaft portion 73 of the clip body 7, so that the clip body 7 and the cylindrical body 74 are integrated and can move in the front-rear direction. On the outer surface of the cylindrical body 74, a plurality of guide protrusions 74c are integrally formed, and the guide protrusions 74c engage with and are movable along the cam groove 41b of the cam portion 41 in the front-rear direction, thereby preventing the cylindrical body 74 from rotating within the shaft cylinder 2. The cylindrical body 74 is obtained by a molded body of synthetic resin (for example, polyacetal resin).

[0089] Figures 32 to 33 show the rotating member 6. The rotating member 6 is provided with a plurality of (for example, four) ridges 61 extending in the front-rear direction on its outer surface, and the ridges 61 are engaged with the cam teeth 41a of the cam portion 41 and the cam groove 41b of the cam portion 41. Inside the rotating member 6, an inner hole penetrating in the front-rear direction is formed. On the inner surface of the inner hole of the rotating member 6, inward protrusions 62 are formed. The rotating member 6 is obtained by a molded body of synthetic resin (for example, polyacetal resin).

[0090] Figure 35 shows the engagement state between the clip body 7 and the rotating member 6 in the state where the pen tip protrudes. The inward protrusion 62 of the rotating member 6 engages with and overrides the second outward protrusion 73e of the clip body 7. Thereby, the clip body 7 and the rotating member 6 are prevented from coming off. Further, the rotating member 6 has play in the front-rear direction and is rotatably attached. The play (movable amount) in the front-rear direction is set to a small dimension such that the engagement and disengagement between the ridge 61 of the rotating member 6 and the cam teeth 41a of the cam portion 41 are possible.

[0091] ·Assembly of the clip body The assembly of the clip body 7 will be described. From the rear end opening of the first long hole 44 of the intermediate shaft 4, the base 72 of the clip body 7 is inserted into the first long hole 44, and the cylindrical shaft portion 73 of the clip body 7 is inserted into the intermediate shaft 4. Thereafter, the inner surface of the rear shaft 5 is fitted to the outer surface of the reduced diameter portion 43 of the intermediate shaft 4 so that the first long hole 44 of the intermediate shaft 4 and the second long hole 51 of the rear shaft 5 communicate in the radial direction (overlap in the radial direction), and the base 72 of the clip body 7 is inserted into the second long hole 51 from the front end opening of the second long hole 51. Thereby, the intermediate shaft 4 and the rear shaft 5 are connected, and the slide hole 21 extending in the front-rear direction is formed by the first long hole 44 and the second long hole 51, and the clip body 7 (a part of the clip main body 71 and the base 72) protrudes radially outward from the slide hole 21, and the clip body 7 is configured to be slidable in the front-rear direction (slidable in the front-rear direction) along the slide hole 21. At this time, the outward protrusion 45 on the outer surface of the reduced diameter portion 43 of the intermediate shaft 4 and the inward protrusion 53 on the inner surface of the rear shaft 5 are engaged with each other by overcoming.

[0092] By connecting the rear shaft 5 to which the friction portion 10 is fixed to the rear end portion of the intermediate shaft 4, the friction portion 10 is always fixed to the rear end of the shaft cylinder 2. Further, the front shaft 3 and the intermediate shaft 4 are detachably connected by screwing, whereby the writing body 9 can be replaced.

[0093] ·Protrusion and retraction mechanism The protrusion and retraction mechanism is a side slide type protrusion and retraction mechanism using a rotary cam mechanism. The protrusion and retraction mechanism includes a cam portion 41 formed on the inner surface of the intermediate shaft 4, a rotating member 6 that engages with the cam portion 41 and abuts against the rear end of the writing body 9, a clip body 7 that engages with the rotating member 6 and protrudes radially outward from the slide hole 21, and an elastic body 8 (for example, a compression coil spring) that is housed in the shaft cylinder 2 and biases the writing body 9 rearward. The protrusion and retraction mechanism of the present embodiment is a double knock type in which both the pen tip protrusion operation and the pen tip retraction operation slide the clip body 7 forward.

[0094] The cam portion 41 includes a plurality of serrated cam teeth 41a protruding forward, and a plurality of cam grooves 41b formed between the cam teeth 41a and extending in the front-rear direction. The rotating member 6 includes a plurality of (for example, four) protrusions 61 extending in the longitudinal direction on its outer surface, and the protrusions 61 are engaged with the cam teeth 41a of the cam portion 41 and the cam grooves 41b of the cam portion 41. At the front end of the cylindrical body 74 attached to the shaft portion 73 of the clip body 7, cam teeth 74a that engage with the rear end of the protrusion 61 of the rotating member 6 are integrally formed.

[0095] ·Protrusion and retraction of the pen tip When the clip body 7 is slid forward from the state where the pen tip is retracted, against the biasing force towards the rear by the elastic body 8, the rotating member 6 is pressed forward by the cylindrical body 74 attached to the shaft portion 73 of the clip body 7. As the protrusion 61 of the rotating member 6 moves forward along the cam groove 41b, the rotating member 6 presses the rear end of the writing body 9 forward, and the pen tip 91 protrudes outside from the front end hole 31. At this time, the rotating member 6 rotates by a certain angle with respect to the cam portion 41 due to the contact between the cam teeth 74a of the cylindrical body 74 attached to the shaft portion 73 and the protrusion 61 of the rotating member 6. Thereby, the protrusion 61 of the rotating member 6 is engaged with the cam teeth 41a of the cam portion 41, and the pen tip protruding state is maintained.

[0096] When the clip body 7 is slid forward from the state where the pen tip protrudes, the cylindrical body 74 attached to the shaft portion 73 of the clip body 7 presses the rotating member 6 forward, and the rotating member 6 rotates by a certain angle with respect to the cam portion 41 due to the contact between the cam teeth 74a of the cylindrical body 74 and the protrusion 61 of the rotating member 6. Thereby, the engagement state between the protrusion 61 and the cam teeth 41a of the cam portion 41 is released, and due to the biasing force towards the rear by the elastic body 8, the protrusion 61 moves rearward along the cam groove 41b of the cam portion 41. As the rotating member 6 moves rearward, the writing body 9 moves rearward, and the pen tip retracted state is achieved.

[0097] ·Friction portion In the present embodiment, the elastic material constituting the friction portion 10 is preferably a synthetic resin having elasticity (rubber, elastomer). For example, silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butadiene-styrene copolymer), fluororesin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM), etc. may be mentioned. The synthetic resin having elasticity constituting the friction portion 10 is preferably made of a low-wear elastic material that hardly generates wear debris (shavings) during friction, rather than a high-wear elastic material (such as eraser rubber). Further, the friction portion 10 may be provided at least on the outer surface of the rear end portion of the shaft cylinder 2. For example, a friction portion 10 made of an elastic material is press-fitted, engaged, screwed, fitted, adhered, two-color molded, etc. to the rear end portion of the shaft cylinder 2 or the rear end portion of the rear shaft 5, or a configuration in which the entire shaft cylinder 2 or the entire rear shaft 5 is integrally formed of an elastic material may be mentioned.

[0098] ·Thermochromic ink In the present embodiment, the thermochromic ink is preferably a reversible thermochromic ink. The reversible thermochromic ink can be configured by singly or jointly using various types such as a heat-decoloring type that decolors by heating from the colored state, a color memory retention type that alternately stores and retains the colored state or the decolored state in a specific temperature range, or a heat-coloring type that colors by heating from the decolored state and returns to the decolored state by cooling from the colored state.

[0099] Further, as the coloring material contained in the reversible thermochromic ink, a reversible thermochromic pigment in which a reversible thermochromic composition containing at least the essential three components of (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reaction medium that determines the color-forming reaction temperature of both of them is encapsulated in microcapsules is preferably used.

[0100] In this embodiment, as shown in FIG. 10, the shape of the curve plotting the change in coloring density due to temperature change follows different paths when the temperature is increased from the lower temperature side than the discoloration temperature range and when it is decreased from the higher temperature side than the discoloration temperature range, and the coloring state in the low temperature range below the complete coloring temperature (t1) or the decoloring state in the high temperature range above the complete decoloring temperature (t4) can be memorized and retained in a specific temperature range (temperature range between t2 and t3 (substantially two-phase holding temperature range)). It is preferable to apply a color memory holding type thermochromic ink. In FIG. 10, ΔH indicates the temperature width (i.e., hysteresis width) indicating the degree of hysteresis. When the value of ΔH is small, only one of the two states before and after discoloration can exist. When the value of ΔH is large, it becomes easier to hold each state before and after discoloration.

[0101] In this embodiment, the discoloration temperature due to the frictional heat of the frictional portion 10 of the thermochromic ink is set to 25°C to 95°C (preferably 36°C to 95°C). That is, in this embodiment, it is effective to set the high temperature side discoloration point [complete decoloring temperature (t4)] in the range of 25°C to 95°C (preferably 36°C to 90°C) and set the low temperature side discoloration point [complete coloring temperature (t1)] in the range of -30°C to +20°C (preferably -30°C to +10°C). Thereby, it is possible to effectively function to retain the color presented in the normal state (daily living temperature range), and it is possible to easily discolor the handwriting with the reversible thermochromic ink by the frictional heat of the frictional portion 10.

[0102] In the thermochromic writing instrument 1 of this embodiment, by fixing the friction portion 10 to the outer surface of the rear end of the shaft cylinder 2, the movement of the friction portion 10 backward during the friction operation is blocked, so that a stable friction operation can be performed using the friction portion 10. Further, in the thermochromic writing instrument 1 of this embodiment, an operation portion for operating the protrusion and retraction of the pen tip is provided on the clip body 7, and by separating the friction portion 10 from the clip body 7 (operation portion), when the pen tip 91 protrudes and retracts, the clip body 7 is operated and the friction portion 10 is not operated, so that the friction portion 10 can be prevented from being soiled by hand dirt or the like. Further, in the thermochromic writing instrument 1 of this embodiment, although the clip body 7 is provided on the outer surface of the shaft cylinder 2, compared with the conventional multi-core type side-slide type thermochromic writing instrument, there are fewer protruding portions, the degree of freedom in the external design is increased, and a smart appearance can be obtained.

[0103] In the thermochromic writing instrument 1 of this embodiment, the protruding and retracting mechanism is a side-slide type protruding and retracting mechanism using a rotary cam mechanism, and both the pen tip protruding operation and the pen tip retracting operation are of the type in which the clip body 7 is slid forward (so-called double-knock type protruding and retracting mechanism), so the operation method is simple and the user can easily acquire the operation method.

[0104] In the thermochromic writing instrument 1 of this embodiment, the slide hole 21 is formed by the first long hole 44 opened rearward and the second long hole 51 opened forward. When connecting the intermediate shaft 4 and the rear shaft 5 (that is, when forming the slide hole 21), the clip body 7 can be inserted into the first long hole 44 and the second long hole 51, the clip body 7 can be easily inserted into the slide hole 21, and easy insertion and assembly of the clip body 7 and the shaft cylinder 2 can be achieved.

[0105] In the thermochromic writing instrument 1 of this embodiment, the side wall of the intermediate shaft 4 and the side wall of the rear shaft 5 are connected so as to overlap in the radial direction, and the first long hole 44 and the second long hole 51 are communicated in the radial direction, so that it is possible to avoid the entire shaft cylinder 2 becoming unnecessarily long.

[0106] In the thermochromic writing instrument 1 of this embodiment, the clip body 7 has a shaft portion 73 that is housed in the shaft cylinder 2 and extends in the front-rear direction. The shaft portion 73 and the rotating member 6 are locked in the front-rear direction in a state where they can rotate relative to each other and have play in the front-rear direction. As a result, in the pen tip protruding state, inadvertent movement of the clip body 7 in the front-rear direction is suppressed. As a result, even when gripping near the clip body 7 in the pen tip protruding state, a stable friction operation becomes possible.

[0107] In the thermochromic writing instrument 1 of this embodiment, a guide groove 48 extending in the front-rear direction is formed on the outer surface of the shaft cylinder 2 in front of the slide hole 21. A ball portion 71a is projectingly provided on the inner surface of the front portion of the clip body 7. As the ball portion 71a slides in the front-rear direction in the guide groove 48 as the clip body 7 moves in the front-rear direction, the clamping performance of the clip is improved and wobbling of the clip body 7 in the lateral direction (circumferential direction) can be prevented.

[0108] In the thermochromic writing instrument 1 of this embodiment, the friction portion 10 is made of an elastic material, and a part of the friction portion 10 can also be brought into contact with the clip body 7 in the pen tip retracted state. Thereby, when changing from the pen tip protruding state to the pen tip retracted state, the writing body 9 and the clip body 7 move rearward due to the biasing force of the elastic body 8 in the rearward direction, and the clip body 7 and the friction portion 10 made of an elastic material come into contact with each other. Therefore, the impact applied to the writing body 9 at that time can be alleviated. As a result, backflow of the ink in the writing body 9 and entry of air from the pen tip 91 can be prevented.

Explanation of Reference Numerals

[0109] 1 Thermochromic writing instrument 2 Shaft cylinder 21 Slide hole 3 Front shaft 31 Front end hole 32 Male screw portion 3a Main body 3b Gripping portion 4 Intermediate shaft 41 Cam portion 41a Cam teeth 41b Cam groove 42 Step portion 43 Reduced diameter part 44 First long hole 45 Outward protrusion 46 Neck part 47 Locking protrusion 48 Guide groove 49 Groove 5 Rear shaft 51 Second long hole 52 Mounting hole 53 Inward protrusion 6 Rotating member 61 Ridge 62 Inward protrusion 7 Clip body 71 Clip main body 71a Ball part 72 Base part 72a Rib 73 Shaft part 73a Cam tooth 73b Large diameter part 73c Small diameter part 73d First outward protrusion 73e Second outward protrusion 74 Cylindrical body 74a Cam tooth 74b Inward protrusion 74c Guide protrusion 7a Main part 8 Elastic body 9 Writing body 91 Pen tip 92 Ink storage tube 93 Heat-sensitive ink 94 Follow body 95 Tail plug 10 Friction part

Claims

1. A thermochromic writing instrument comprising a writing body containing thermochromic ink therein, which is accommodated in a shaft cylinder, and an operating body provided on the shaft cylinder is operated to move the writing body in the front-rear direction, and the pen tip of the writing body is configured to be able to protrude from and retract into the tip of the writing instrument, a friction portion capable of thermochromically changing the writing of the thermochromic ink by the frictional heat generated when the writing is rubbed, and a clip body as at least one of the operating bodies, wherein the friction portion is provided at the rear end of the shaft cylinder, and the clip body is provided at a portion other than the rear end of the shaft cylinder. The thermochromic writing instrument is characterized in that.

2. The thermochromic writing instrument according to claim 1, further comprising only a single clip body as the operating body, and by operating the single clip body, the pen tip of the writing body can be brought into a protruding state and a retracted state.

3. The thermochromic writing instrument according to claim 1 or 2, further comprising an advancing / retracting mechanism configured to bring the pen tip of the writing body from a retracted state to a protruding state by sliding the clip body disposed in a slide hole provided in a side wall of the shaft cylinder forward in the front-rear direction.

4. The shaft cylinder is composed of two or more parts that can be connected to each other, and first or second elongated holes that are open at the front end or the rear end and extend in the front-rear direction are respectively provided on each side wall of the two parts constituting the shaft cylinder. When the two parts are connected, the first and second elongated holes communicate with each other to form the slide hole. The thermochromic writing instrument according to claim 3.

5. The thermochromic writing instrument according to claim 4, wherein each side wall of the two parts constituting the shaft cylinder is connected so as to overlap each other in the radial direction, and the first and second elongated holes communicate with each other in a state of overlapping each other in the radial direction to form the slide hole.

6. inserting a base portion of the clip body into the first elongated hole provided in one of the parts constituting the shaft cylinder; while inserting the base portion of the clip body into the second elongated hole provided in the other part constituting the shaft cylinder, connecting the other part to the one part, and communicating the second elongated hole with the first elongated hole to form the slide hole; The thermochromic writing instrument according to claim 4 or 5, wherein the clip body is assembled to the slide hole through the above steps.

7. A cam mechanism as the protruding and retracting mechanism is provided in the shaft cylinder. The cam mechanism includes a cam portion and a protrusion that can engage at different positions in the front-rear direction alternately. By sliding the clip body forward, the cam portion and the protrusion are engaged at different positions in the front-rear direction alternately, and the pen tip of the writing body is made to protrude or retract alternately. The thermochromic writing instrument according to any one of claims 3 to 6.

8. As the protruding and retracting mechanism, a plurality of cam teeth and cam grooves extending in the front-rear direction and arranged alternately along the circumferential direction, and a rotating member rotatably arranged behind the writing body and having a plurality of ridges that can engage with the cam teeth or the cam grooves alternately, and a plurality of other cam teeth provided on the clip body for rotating the rotating member, and an elastic body for biasing the writing body backward are provided in the shaft cylinder. By sliding the clip body forward against the biasing force of the elastic body, the ridges are engaged with the cam teeth or the cam grooves alternately, and the pen tip of the writing body is made to protrude or retract alternately. The thermochromic writing instrument according to claim 7.

9. The clip body has a shaft portion housed in the shaft cylinder and extending in the front-rear direction, and the shaft portion and the rotating member are locked to each other in a state of having play in the front-rear direction. The thermochromic writing instrument according to claim 8.

10. A guide groove extending in the front-rear direction is formed on the outer surface of the shaft cylinder in front of the slide hole, a ball portion is provided protruding from the inner surface of the front portion of the clip body, and as the clip body moves in the front-rear direction, the ball portion slides in the guide groove in the front-rear direction. The thermochromic writing instrument according to any one of claims 3 to 9.

11. The friction portion is made of an elastic material, and a part of the friction portion abuts against the clip body in a state where the pen tip is retracted. The thermochromic writing instrument according to any one of claims 1 to 10.

12. The friction portion is made of an elastic material, and is fixed to the rear end of the shaft cylinder by press-fitting, engaging, screwing, fitting, adhering, two-color molding, or the entire shaft cylinder is formed of the elastic material as the friction portion. The thermochromic writing instrument according to any one of claims 1 to 11.

13. A thermochromic ink is housed inside the writing body, a pen tip capable of discharging the thermochromic ink is provided at the front end of the writing body, the writing body is housed in the shaft cylinder so as to be movable in the front-rear direction in a state of being biased backward, and the pen tip of the writing body is configured to protrude and retract from the front end hole of the shaft cylinder. The thermochromic writing instrument is as follows. A slide hole extending in the front-rear direction is provided in the side wall of the shaft cylinder, a clip body protrudes radially outward from the slide hole, the clip body is configured to be movable in the front-rear direction along the slide hole, and the pen tip is protruded from the front end hole of the shaft cylinder by sliding the clip body forward from the state where the pen tip is immersed, and a projecting and retracting mechanism is provided to immerse the pen tip by operating the clip body from the state where the pen tip protrudes. A friction part is provided at the rear end of the shaft cylinder to rub the handwriting of the thermochromic ink and thermochromically change the handwriting with the frictional heat generated at that time. A thermochromic writing instrument characterized by this.

14. The projecting and retracting mechanism is a side slide type projecting and retracting mechanism using a rotary cam mechanism, and at least includes a cam part formed on the inner surface of the shaft cylinder, a rotating member that engages with the cam part and abuts against the rear end of the writing body, a clip body having cam teeth that engage with the rotating member, and an elastic body that is housed in the shaft cylinder and biases the writing body rearward. The thermochromic writing instrument according to claim 13, wherein both the pen tip projecting operation and the pen tip retracting operation are of a type that slides the clip body forward.

15. The shaft cylinder is composed of a front shaft, an intermediate shaft connected to the rear end portion of the front shaft, and a rear shaft connected to the rear end portion of the intermediate shaft. A front end hole through which the pen tip can project and retract is provided at the front end of the front shaft, a cam part is provided on the inner surface of the intermediate shaft, a first long hole that is open rearward and extends in the front-rear direction is provided at the rear end portion of the intermediate shaft, a second long hole that is open forward and extends in the front-rear direction is provided at the front end portion of the rear shaft, the rear end portion of the intermediate shaft and the front end portion of the rear shaft are connected so that the first long hole and the second long hole communicate with each other, the slide hole is formed in the side wall of the shaft cylinder by the first long hole and the second long hole, and the thermochromic writing instrument according to claim 13 or 14, wherein a friction part is provided at the rear end of the rear shaft.

16. The thermochromic writing instrument according to claim 15, wherein the side wall of the intermediate shaft and the side wall of the rear shaft are connected so as to overlap each other in the radial direction, and the first long hole and the second long hole are communicated with each other in the radial direction.

17. The clip body has a shaft portion that is housed in the shaft cylinder and extends in the front-rear direction, and the shaft portion and the rotating member are locked in the front-rear direction in a state where they can rotate relative to each other and have play in the front-rear direction. The thermochromic writing instrument according to any one of claims 13 to 16.

18. A guide groove extending in the front-rear direction is formed on the outer surface of the shaft cylinder in front of the slide hole, a ball portion is protruded on the inner surface of the front portion of the clip body, and the ball portion slides in the front-rear direction in the guide groove as the clip body moves in the front-rear direction. The thermochromic writing instrument according to any one of claims 13 to 17.

19. The thermochromic writing instrument according to any one of claims 13 to 18, wherein the friction portion is made of an elastic material, and a part of the friction portion abuts on the clip body in a state where the pen tip is immersed.

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