JP2012232481A - Multi-core type thermochromic writing utensil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-core type thermochromic writing utensil whereby manufacturing costs of a friction core body can be reduced.SOLUTION: At least a writing core body 6 and at least one friction core body are accommodated in a barrel 2 to be movable in a forward backward direction. The writing core body 6 includes a pen point 61 which has a thermochromic ink stored inside and can eject the thermochromic ink to the front end. The friction core body is equipped to the front end with a tip part which rubs against handwriting of the thermochromic ink and can thermally discolor the handwriting by a frictional heat generated at the time. Operating parts 63 and 73 are provided to respective rear ends of the writing core body 6 and the friction core body. The friction core body consists of the tip part, the operating part 73, and a shaft part having the tip part provided to a front end portion and the operating part 73 provided to a rear end portion. The tip part, the shaft part and the operating part 73 are formed of a synthetic resin in one piece.

Description

The present invention relates to a multi-core thermochromic writing instrument. Specifically, the present invention relates to a multi-core thermochromic writing instrument in which a plurality of core bodies are accommodated in a shaft cylinder so as to be able to appear and retract.

In Patent Document 1, a writing core and a friction core are accommodated in a shaft cylinder so as to be movable in the front-rear direction, thermochromic ink is accommodated in the writing core, and the friction core is contained. A thermochromic writing instrument is disclosed in which a tip portion capable of rubbing the handwriting of thermochromic ink on the front end of the body is provided.

JP 2008-247025 A

In the thermochromic writing instrument of Patent Document 1, the friction core is composed of three parts: a tip, a shaft, and an operating body. Therefore, an assembly process of three parts is required, and the manufacturing cost of the friction core increases.

The present invention is intended to solve the above-described conventional problems and to provide a multi-core thermochromic writing instrument capable of reducing the manufacturing cost of a friction core. In the present invention, “front” refers to the pen tip side, and “rear” refers to the opposite side. In the present invention, the “pen nib immersive state” refers to a state in which the pen nib is immersed in the shaft cylinder, and the “pen nib protruding state” refers to a state in which the pen nib projects outward from the front end of the shaft cylinder. Say. In the present invention, the “chip part immersing state” means a state where the chip part is immersed in the shaft cylinder, and the “chip part protruding state” means a state where the chip part protrudes outside from the front end of the shaft cylinder. Say.

In the first invention of the present application, at least one writing core body 6 and at least one friction core body are accommodated in the shaft cylinder 2 so as to be movable in the front-rear direction, and the writing core body 6 is A nib 61 which contains thermochromic ink inside and discharges the thermochromic ink at the front end, and the friction core rubs the handwriting of the thermochromic ink at the front end. A tip portion capable of thermally discoloring the handwriting by the generated frictional heat is provided, and operating portions 63 and 73 are provided at rear ends of the writing core body 6 and the friction core body, and the writing core body 6 and the writing core Each of the friction cores is urged rearward by the elastic body 21, and a plurality of window holes 41 extending in the axial direction are provided in the side wall of the shaft tube 2 in the radial direction. The respective operation parts 63 and 73 protrude outward in the direction, and one operation part slides forward along the window hole 41. By doing so, the pen tip 61 of the writing core 6 having the one operation portion or the tip portion of the friction core is protruded from the front end hole 31 of the shaft cylinder 2, and the other one that has been in the protruding state first A multi-core thermochromic writing instrument that immerses the nib 61 of the writing core 6 or the tip portion of the friction core into the shaft tube 2, wherein the friction core includes the tip portion and the operation Part 73, a shaft part provided with the tip part at the front end part and the operation part 73 provided at the rear end part, and the chip part, the shaft part and the operation part 73 are integrally formed of synthetic resin. It is a requirement that

In the multi-core thermochromic writing instrument 1 of the first invention, the friction core includes the tip portion, the operation portion 73, and the tip portion at a front end portion, and the operation portion 73 is provided at a rear end. Since the tip portion, the shaft portion, and the operation portion 73 are integrally formed of a synthetic resin, the manufacturing cost of the friction core can be reduced.

According to a second aspect of the present invention, in the multi-core thermochromic writing instrument 1 according to the first aspect of the present invention, an engagement protrusion is formed on the outer surface of the rear end portion of the writing core 6 on the opposite side in the radial direction. An engaging protrusion 74 is formed integrally on the outer surface of the operating portion 73 opposite to the radial direction of the rear end portion of the shaft portion of the shaft portion of the friction core, and the friction core body when the tip portion is retracted It is a requirement that the other engaging core 74 or the engaging protrusions 64 and 74 of the friction core are in contact with the engaging protrusion 74.

The multi-core thermochromic writing instrument 1 according to the second aspect of the present invention is provided with an engagement protrusion 64 on the outer surface of the rear end portion of the writing core 6 on the opposite side to the radial direction of the operation portion 63, An engaging protrusion 74 is integrally formed on the outer surface of the operating portion 73 opposite to the radial direction of the rear end portion of the shaft portion of the core body, and other than the engaging protrusion 74 of the friction core body when the tip portion is retracted. Since the writing core body 6 or the friction core body engagement protrusions 64 and 74 are in contact with each other, the manufacturing cost of the friction core body can be further reduced.

The third invention of the present application requires that the shaft portion has flexibility in the multi-core thermochromic writing instrument 1 of the first or second invention.

In the multi-core thermochromic writing instrument 1 of the third invention, since the shaft portion has flexibility, the shaft portion easily bends in the protruding state of the tip portion of the friction core body. The portion can be easily protruded from the front end hole 31 of the shaft tube 2.

-Friction core In the present invention, the synthetic resin constituting the friction core is, for example, polypropylene, polyethylene, ABS resin, polyacetal resin, silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS. Examples include resins (styrene-ethylene-butylene-styrene copolymers), fluorine resins, chloroprene resins, nitrile resins, polyester resins, ethylene propylene diene rubber (EPDM), and the like.

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

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

In the present invention, as shown in FIG. 8, the shape of the curve plotting the change in color density due to the temperature change is opposite to the case where the temperature is raised from the lower temperature side than the color change temperature range, and from the higher temperature side than the color change temperature range. The color changes by following a different path depending on the descending state, and the color development state in the low temperature range below the complete color development temperature (t ₁ ) or the color erase state in the high temperature range above the complete color erase temperature (t ₄ ) It is preferable to apply a color memory retention type thermochromic ink that can be stored and retained in a specific temperature range [temperature range between t _{2 and} t ₃ (substantially two-phase retention temperature range)]. In FIG. 8, ΔH represents a temperature width (ie, hysteresis width) indicating the degree of hysteresis. When the value of ΔH is small, only one of the two states before and after the color change can exist. When the value of ΔH is large, it is easy to maintain each state before and after the color change.

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

The multi-core thermochromic writing instrument of the present invention can reduce the manufacturing cost of the friction core.

It is a longitudinal cross-sectional view which shows the pen tip immersion state and chip | tip part immersion state of embodiment of this invention. It is a longitudinal cross-sectional view which shows the pen tip protrusion state of FIG. It is a longitudinal cross-sectional view which shows the chip | tip part protrusion state of FIG. It is a side view of FIG. It is a side view at the time of replacement | exchange of the friction core of FIG. It is a longitudinal cross-sectional view of the writing core of FIG. It is a longitudinal cross-sectional view of the friction core body of FIG. It is explanatory drawing which shows the color change behavior of a thermochromic ink.

An embodiment of the present invention is shown in FIGS.
In the multi-core thermochromic writing instrument 1 of the present embodiment, one writing core 6 and one friction core 7 can move in the longitudinal direction (axial direction) in the shaft cylinder 2. Is housed in. Each of the writing core 6 and the friction core 7 is urged rearward by an elastic body 21 (specifically, a compression coil spring).

The shaft cylinder 2 includes a front shaft 3 made of a tapered cylindrical body, and a cylindrical rear shaft 4 attached to the rear end portion of the front shaft 3 by screwing or press-fitting. A front end hole 31 through which the pen tip 61 of the writing core 6 and the tip portion 71 of the friction core 7 can protrude is provided in the front end of the front shaft 3 in the axial direction. The front shaft 3 and the rear shaft 4 are obtained by injection molding of a synthetic resin (for example, polycarbonate). The shaft cylinder 2 (front shaft 3 and rear shaft 4) may be formed of metal.

A plurality of (two in this case) elongated windows extending in the front-rear direction according to the number of writing cores 6 and friction cores 7 housed in the shaft cylinder 2 are provided on the rear side wall of the rear shaft 4. A hole 41 is provided in the radial direction. An opening 42 is formed at the rear end portion of the rear shaft 4 so as to penetrate in the axial direction and open radially outward. The opening 42 communicates with the window hole 41 at the rear end of the rear shaft 4 (that is, the rear end of the shaft cylinder 2), whereby the rear end of the window hole 41 is notched rearward and opened rearward. On the other hand, the front end of the window hole 41 is always closed.

A locking wall portion 43 made of a rib extending in the front-rear direction is formed on the inner surface of the side wall between the window holes 41 of the rear shaft 4, and the pen tip 61 or the tip portion 71 is formed on the locking wall portion 43. The rear end of the writing core 6 corresponding to the protruding pen tip 61 or the rear end of the friction core corresponding to the tip portion 71 is locked.

A clip 44 is provided on the outer surface of the side wall between the window holes 41 of the rear shaft 4.

In a state where the pen tip 61 protrudes to the outside from the front end of the shaft cylinder 2 (when writing), the inner surface of the front end hole 31 supports the outer surface in the radial direction of the pen tip 61, and the tip portion 71 protrudes to the outside from the front end of the shaft cylinder 2. In this state (at the time of friction discoloration), the inner surface of the front end hole 31 supports the radially outer surface of the tip portion 71. Since the front end portion of the shaft cylinder 2 provided with the front end hole 31 is formed integrally with the shaft cylinder 2 (front shaft 3), it is made of the same material as the shaft cylinder 2 (for example, polycarbonate resin).

-Lid part At the rear-end part of the said rear axis | shaft 4, the cover part 5 which makes the said opening part 42 openable and closable is provided rotatably. One end of the lid 5 is attached to the base of the clip 44 by a hinge 52 so as to be rotatable. A contact wall 51 is formed on the front surface of the lid 5. The abutting wall portion 51 abuts the rear end of the writing core 6 in the pen tip immersing state and the rear end of the friction core 7 in the tip portion immersing state.

On the front surface of the other end portion of the lid portion 5, an engaging portion 53 including a concave portion or a hole portion is provided. At the rear end of the shaft cylinder 2 (rear shaft 4), an engaged portion 45 made of a convex portion engageable with the engaging portion 53 is provided. An inward projection is formed on the inner surface of the engaging portion 53, while an outward projection that can get over and engage with the inward projection is formed on the outer surface of the engaged portion 45.

The engaging portion 53 and the engaged portion 45 are in an engaged state with each other when the lid portion 5 closes the opening 42 (specifically, the inward projection and the outward projection are overcoming and locked) ) The contact state between the writing core 6 or the friction core body and the contact wall portion 51 on the front surface of the lid portion 5 by the rearward urging of the elastic body 21 is not released, and the lid Part 5 never opens.

Writing core The writing core 6 is a ballpoint pen refill, and includes a ballpoint pen tip (that is, a pen tip 61) in which a ball is rotatably held at the front end, the ballpoint pen tip at the front end, and a rear end. The ink storage tube 62 is opened and an operation unit 63 is provided at the rear end of the ink storage tube 62. Inside the ink storage tube 62, a thermochromic ink 63 made of an aqueous gel having shear thinning viscosity is stored. The rear end of the thermochromic ink 63 in the ink containing tube 62 is filled with a follower 64 made of a high-viscosity fluid that advances as the ink is consumed.

The nib 61 is composed of a ballpoint pen tip including a ball rotatably held at the front end. Inside the nib 61 is accommodated a ball bullet 65 for pushing the front end ball forward. The ball elastic body 65 has a configuration in which a rod portion is provided at the front end portion of the 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 pressed close to the inner surface of the front end edge of the front end of the ballpoint pen tip by the forward urging of the ball projecting element 65, thereby preventing ink leakage and ink evaporation from the front end of the pen tip 61. . The ballpoint pen tip may be directly attached to the front end opening of the ink containing tube 62 by press fitting or the like, but in this embodiment, it is fixed to the front end opening of the ink containing tube 62 via the pen tip holder.

The thermochromic ink 63 has a low temperature side color change point (complete color development temperature t ₁ ) set to an arbitrary temperature in the range of −30 ° C. to −10 ° C., and a high temperature side color change point (complete color erasing temperature t ₄ ). An ink having a reversible thermochromic composition that is set to an arbitrary temperature in the range of 60 ° C. to 80 ° C. and has a hysteresis width ΔH in the range of 40 ° C. to 60 ° C. is employed.

Friction core body The friction core body 7 includes a tip portion 71, a shaft portion 72 in which the tip portion 71 is integrally formed at the front end, and an operation portion 73 formed integrally at the rear end portion of the shaft portion. And the engaging protrusion 74. The shaft portion 72 is a columnar member having the same diameter as the ink containing tube 62 of the writing core 6. The friction core (that is, the tip portion, the shaft portion, the operation portion 73, and the engaging protrusion 74) is made of, for example, polypropylene resin, polyethylene resin, SBS resin, SEBS resin, or the like.

Chip part The front end of the chip part 71 has a rounded shape. Thereby, at the time of friction discoloration, smooth contact between the front end of the tip portion 71 and the writing surface is possible, and generation of frictional heat is obtained by obtaining an appropriate contact area between the front end of the tip portion 71 and the writing surface. It becomes easy. In addition to this, the front end of the tip portion 71 may have a chisel shape, a shell shape, a cylindrical shape, a conical shape, a prismatic shape, a pyramid shape, or the like. The tip portion 71 slides on the inner surface of the front end hole 31 when the tip portion is projected and retracted.

-Operation part, engagement protrusion The operation part 63 * 73 is provided in each of the rear-end part of the said writing core 6 and the rear-end part of the said friction core 7. Each of the operation portions 63 and 73 is formed at the rear end portion and protrudes from the window hole 41 of the shaft tube 2 to the outside. Engaging protrusions 64 and 74 are formed on the opposite side of the operation parts 63 and 73. The engagement protrusions 64 and 74 are composed of front protrusions 64a and 74a and rear protrusions 64b and 74b arranged behind the front protrusions 64a and 74a. (See Figs. 6 and 7)

When the pen tip 61 of the writing core 6 is in an immersive state (see FIGS. 1 and 3), the rear end portion of the writing core 6 is in contact with the abutting wall 51 formed on the front surface of the lid 5. Abutted. On the other hand, when the pen tip 61 of the writing core 6 is in a protruding state (see FIG. 2), the rear end portion of the writing core 6 is engaged with a locking wall portion 43 formed on the inner wall of the shaft tube 2. Stopped.

Similarly, when the tip portion 71 of the friction core 7 is in an immersive state (see FIGS. 1 and 2), the rear end of the friction core 7 is a contact wall portion formed on the front surface of the lid portion 5. 51 abuts. On the other hand, when the tip portion 71 of the friction core 7 is in a protruding state (see FIG. 3), the rear end portion of the friction core 7 is engaged with a locking wall portion 43 formed on the inner wall of the shaft tube 2. Stopped.

As shown in FIG. 2, the front protrusion 74 a at the rear end of the friction core 7 in the tip part immersion state is a writing in which the pen tip protrudes first when the operation part 73 is slid forward. The rear end projecting portion 64b of the rear end portion of the core 6 is brought into contact, and the pen tip protruding state of the writing core 6 is released. Further, as shown in FIG. 3, the front protruding portion 64a at the rear end of the writing core 6 in the pen tip immersing state is in the tip protruding state first when the operating portion 63 is slid forward. The friction core body 7 is brought into contact with the rear protruding portion 74b of the rear end portion of the friction core body 7, and the tip portion protruding state of the friction core body 7 is released.

Display unit The operation part 63 at the rear end of the writing core 6 is made of the thermochromic ink 63 contained in the writing core 6 having the operation part 63 (that is, inside the ink containing tube 62). It is colored in almost the same color as the colored state. Specifically, the operation portion 63 at the rear end portion of the writing core 6 is formed of a synthetic resin colored in substantially the same color as the color of the colored state of the thermochromic ink 63 of the writing core 6. Consists of the body. Accordingly, the operation unit 63 has a display unit that displays the ink color of the colored state of the thermochromic ink 63 accommodated in the writing core 6.

The friction core 7 is transparent, white, gray, or light color. Specifically, each of the friction cores 7 is made of a transparent synthetic resin or a molded body of a synthetic resin exhibiting white, gray, or light color. Thereby, the operation portion 73 of the friction core has a display portion that exhibits a color other than the ink color of the color-changing state of the thermochromic ink 63.

A projectile support part 9 having a cylindrical shape is provided on the inner wall of the barrel 2 (that is, the inner wall of the rear shaft 4). A plurality of inner holes 91 through which the writing core body 6 and the friction core body 7 are inserted are penetrated in the elastic body support portion 9 in the axial direction. The respective elastic bodies 21 are arranged between the rear surface of the elastic body supporting portion 9 and the step portions 65 and 75 of the writing core body 6 and the friction core body 7. The writing core 6 is loosely inserted into each of the elastic bodies 21, and each of the writing core 6 and each of the friction cores has a front end of the elastic body 21 that supports the elastic body. The rear end of each elastic body 21 is locked to the front surface of each step 65 and 75 of each writing core 6 and each friction core.

Further, around each inner hole 91 on the rear surface of the projectile support 9, a holding portion 92 made of a cylindrical protruding portion protruding rearward is formed. The inner surface of each holding portion 92 is press-fitted and held at the outer surface of the front end portion of each elastic body 21. Thereby, when the writing core 6 and the friction core 7 are exchanged, it is possible to prevent the respective elastic bodies 21 from dropping out of the shaft cylinder 2 through the opening 42.

Each of the elastic bodies 21 normally urges the writing core body 6 and the friction core body 7 backward. Each of the elastic bodies 21 is in a compressed state (that is, the writing core 6 and the friction core 7 are rearward in any of the pen tip protruding state, the pen tip immersing state, the tip protruding state, and the tip immersing state. In this state, the back and forth of the respective operation parts 63 and 73 is prevented.

When the operation part 63 of the pen point protruding writing writing core 6 is slid forward along the window hole 41 against the rearward bias of the elastic body 21, the opposite side of the operation part 63 that has been slid The front projecting portion 64a lifts the rear projecting portion 74b of the friction core 7 in the tip projecting state first outward in the radial direction. As a result, the locking state between the locking wall portion 43 of the inner wall of the shaft tube 2 and the rear end of the friction core body that is in the protruding state of the tip portion is released, and the friction core body 7 is located behind the elastic body 21. The tip 71 of the friction core 7 is moved backward by the urging, and the rear end of the friction core 7 is brought into contact with the contact wall 51 on the front surface of the lid 5. Is done. Simultaneously with the immersion of the tip portion 71 of the friction core 7, the pen point 61 of the writing core 6 connected to the operation portion 63 that is slid forwardly protrudes to the outside from the front end hole 31 of the shaft cylinder 2. At the same time, the rear end of the writing core 6 having the operation portion 63 that is slid forward is locked to the locking wall portion 43 of the inner wall of the shaft cylinder 2, and the pen tip protruding state is maintained.

In the present embodiment, when using the writing, by holding the multi-core thermochromic writing instrument 1 in one hand and pressing the operation unit 63 forward, the pen nib is quickly immersed (the state shown in FIGS. 1 and 3). ) To the pen tip protruding state (the state shown in FIG. 2). By writing on the writing surface such as paper with the pen tip 61 in the protruding state, the handwriting by the thermochromic ink 63 can be formed on the writing surface.

When the operation part 73 of the tip part retracting friction core 7 is slid forward along the window hole 41 against the rearward bias of the elastic body 21, the front side of the slid friction core The protruding portion 74a lifts the rear protruding portion 64b of the writing core 6 in the protruding state of the pen tip outward in the radial direction. As a result, the locking state between the locking wall portion 43 of the inner wall of the shaft tube 2 and the rear end of the writing core 6 in the pen tip protruding state is released, and the writing core 6 is located behind the elastic body 21. The pen point 61 of the writing core 6 is moved backward by the bias, and the pen tip 61 is immersed in the shaft cylinder 2, and the rear end of the writing core 6 abuts against the abutting wall 51 on the front surface of the lid 5. Is done. Simultaneously with the immersion of the nib 61 of the writing core 6, the tip portion 71 of the friction core 7 having the operating portion 73 slid forward is projected outside from the front end hole 31 of the shaft cylinder 2. At the same time, the rear end of the friction core having the operation portion 73 that has been slid forward is locked to the locking wall portion 43 of the inner wall of the shaft tube 2 and the tip protruding state is maintained.

In the present embodiment, after the writing, when the handwriting is subjected to frictional discoloration, the multi-core thermochromic writing instrument 1 is held in one hand without greatly changing the multi-core thermochromic writing instrument 1. By pressing the head 73 forward, the tip portion can be quickly brought into the tip portion protruding state (the state shown in FIG. 3) from the tip portion immersed state (the state shown in FIGS. 1 and 2). The tip portion 71 in the protruding state rubs the handwriting by the thermochromic ink 63 formed on the writing surface, and the handwriting is thermally discolored (here, colorless) by the frictional heat generated at that time. it can.

-Replacement of writing core, replacement of friction core The writing core 6 and the friction core 7 in the present embodiment will be described. When the writing core 6 or the friction core 7 is replaced, the lid 5 is opposite to the hinge 52 of the lid 5 from the state in which the lid 5 closes the opening 42 at the rear end of the shaft cylinder 2 (see FIG. 4). The operation end on the side is pressed rearward, the engagement between the engaging portion 53 and the engaged portion 45 is released, the lid portion 5 is rotated rearward, and the opening 42 at the rear end of the shaft tube 2 is opened. Open. When the opening 42 is opened, the respective operation parts 63 and 73 are projected from the opening 42 to the outside rear by the rear urging of the bullet 21. In the state where the opening 42 at the rear end of the shaft cylinder 2 is opened (see FIG. 5), the writing core 6 (that is, writing) connected to the operating parts 63 and 73 is taken out by taking out the operating parts 63 and 73. Core body refill) or friction core body 7 (that is, friction core body refill) is taken out from the shaft cylinder 2 through the opening 42, and then a new writing core body 6 or a new friction core The body 7 is inserted into the shaft cylinder 2 through the opening 42. Then, the rear end of the writing core 6 or the rear end of the friction core is brought into contact with the abutting wall 51 of the lid 5, and the lid 5 is pressed while pressing the operation portions 63 and 73 forward. After rotating forward, the engaging portion 53 and the locked portion are engaged, and the opening 42 is closed. Thereby, the replacement work of the writing core 6 and the friction core 7 is completed.

In the multicore thermochromic writing instrument 1 of the present embodiment, the friction core includes the tip portion, the operation portion 73, and the tip portion at a front end portion, and the operation portion 73 is provided at a rear end portion. Since the tip portion, the shaft portion, and the operation portion 73 are integrally formed of synthetic resin, the manufacturing cost of the friction core can be reduced.

The multi-core thermochromic writing instrument 1 of the present embodiment is different from the multi-core thermochromic writing instrument 1 of the second invention in the radial direction of the operation portion 63 at the rear end of the writing core 6. An engaging protrusion 64 is provided on the outer surface of the friction member, and an engaging protrusion 74 is integrally formed on the outer surface of the rear end portion of the shaft portion of the friction core opposite to the radial direction of the operation portion 73. The frictional core manufacturing cost can be reduced by the other writing core 6 or the frictional core engaging protrusions 64 and 74 coming into contact with the frictional core engaging protrusions 74 at the time of appearance. This can be further reduced.

In the multi-core thermochromic writing instrument 1 of the present embodiment, since the shaft portion is flexible, the shaft portion easily bends in the protruding state of the tip portion of the friction core body. Can be easily projected from the front end hole 31 of the shaft cylinder 2.

DESCRIPTION OF SYMBOLS 1 Multi-core type thermochromic writing instrument 2 Shaft cylinder 21 Bullet body 3 Front shaft 31 Front end hole 4 Rear shaft 41 Window hole 42 Opening part 43 Locking wall part 44 Clip 45 Engagement part 5 Lid part 51 Contact wall part 52 Hinge 53 Engagement 6 Writing Core 61 Pen Tip (Ball Pen Tip)
62 Ink receiving tube 63 Operation part 64 Engaging protrusion 64a Front protrusion 64b Rear protrusion 65 Step part 66 Thermochromic ink 67 Follower 68 Ball elastic body 7 Friction core 71 Tip part 72 Shaft part 73 Operation part 74 Engagement protrusion part 74a Front side protrusion part 74b Rear side protrusion part 75 Step part 9 Projection body support part 91 Inner hole 92 Holding part

Claims (3)

A shaft cylinder contains at least one writing core and at least one friction core so as to be movable in the front-rear direction.
The writing core includes a nib that contains thermochromic ink therein and can eject the thermochromic ink at a front end;
The friction core is provided with a tip portion that can rub the handwriting of the thermochromic ink at the front end and thermally change the handwriting with frictional heat generated at that time.
An operating portion is provided at the rear end of each of the writing core and the friction core, and each of the writing core and the friction core is urged rearward by an elastic body, A plurality of window holes extending in the axial direction are provided in the side wall in the radial direction, the respective operation portions are protruded radially outward from the respective window holes, and one operation portion is moved forward along the window hole. By sliding, the pen tip of the writing core having one of the operation portions or the tip portion of the friction core is protruded from the front end hole of the shaft tube, and another writing core that has been in the protruding state first. A multi-core thermochromic writing instrument that immerses the tip of the body pen tip or the tip of the friction core into the shaft cylinder,
The friction core includes the tip portion, the operation portion, and a shaft portion provided with the tip portion at a front end portion and the operation portion at a rear end portion, the tip portion, the shaft portion, And a multi-core thermochromic writing instrument, wherein the operation part is integrally formed of a synthetic resin. An engagement protrusion is provided on the outer surface of the rear end portion of the writing core opposite to the radial direction of the operation portion, and the opposite end of the operation portion of the rear end portion of the shaft portion of the friction core is opposite to the radial direction. An engaging projection is integrally formed on the outer surface,
2. The multi-core thermochromic writing instrument according to claim 1, wherein another writing core or an engaging protrusion of the friction core is brought into contact with the engaging protrusion of the friction core when the tip portion is projected and retracted. The multi-core thermochromic writing instrument according to claim 1 or 2, wherein the shaft portion has flexibility.

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