JP7642001B2 - Multi-core writing implement - Google Patents

Description

The present invention relates to a multi-core writing instrument.

Multi-core writing instruments that have multiple refills and allow the desired refill to be selectively inserted and removed are known (Patent Document 1 and Patent Document 2).

In the multi-core writing instrument described in Patent Document 1, multiple operating parts (sliding bodies) are arranged along the circumferential direction on the side of the barrel. Each operating part is movable in the front-rear direction. Multiple refills are arranged inside the barrel, and each refill is connected to a corresponding operating part. By advancing the operating part corresponding to the desired refill, the refill can be put into a writing state. Therefore, when switching the refill to be used while writing, writing is first interrupted and the barrel is gripped again, the position of the corresponding operating part corresponding to the desired refill is confirmed, and then the operating part is advanced.

In the multi-core writing instrument described in Patent Document 2, a window hole is formed in the part where the fingertip comes into contact during writing, and the operating shaft, which is the operating part, protrudes radially from the window hole. In the multi-core writing instrument described in Patent Document 2, two refills can be selectively inserted and removed. When switching from a non-writing state to a writing state, first, the operating shaft is rotated in a direction corresponding to the desired refill (tentatively referred to as the "first direction"), then the operating shaft is advanced, and then the operating shaft is rotated in the first direction to engage with the locking part, and the writing state is established. In addition, when switching the refill to be written with during writing, first, the operating shaft is rotated in a direction opposite to the first direction (tentatively referred to as the "second direction"), then the operating shaft is retreated, then further rotated in the second direction, then the operating shaft is advanced, and then the operating shaft is rotated in the second direction to engage with the locking part, and the writing state is established.

JP 2013-049192 A JP 2001-219690 A

With the multi-core writing instrument described in Patent Document 1, every time you switch refills, you need to change your grip on the multi-core writing instrument, confirm the position of the operating part that corresponds to the desired refill, and move the operating part forward, which are cumbersome actions. With the multi-core writing instrument described in Patent Document 2, when switching from a non-writing state to a writing state, and when switching refills while in the writing state, complex finger movements are required, which are also cumbersome actions.

The present invention aims to provide a multi-core writing instrument that allows the user to easily switch refills for writing.

According to one aspect of the present invention, there is provided a multi-core writing instrument comprising a barrel, a first operating part that is movable in the front-rear direction relative to the barrel, multiple writing bodies, and a rotating member that is rotatable about a central axis relative to the barrel while holding the multiple writing bodies, and in which the first operating part and the rotating member cooperate to rotate the rotating member in response to the front-rear movement of the first operating part, thereby moving one of the multiple writing bodies forward. In addition, in the axial direction of the multi-core writing instrument, the writing part side is defined as the "front" side, and the opposite side to the writing part is defined as the "rear" side.

The pen may further include a cam surface, and one of the writing bodies may be advanced by cooperation between the writing bodies and the cam surface in response to the rotation of the rotating member. A cam groove may be formed on one of the first operating part and the rotating member, and a cam protrusion may be formed on the other of the first operating part and the rotating member, and the cam groove and the cam protrusion may be formed in cooperation to rotate the rotating member. The cam groove may be formed in a spiral shape around the central axis. The pen may further include a second operating part, and the writing body that has advanced may appear and disappear from the barrel by a knock operation that presses the second operating part forward. All or a part of the first operating part or the second operating part may be an erasing part that can erase handwriting of the multi-core writing instrument. The first operating part may be disposed in the front half of the barrel.

The aspects of the present invention have the common effect of providing a multi-core writing instrument that allows you to easily switch refills to use.

FIG. 1 is a perspective view of a multi-core writing instrument according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view of the multi-core writing instrument in a non-writing state. FIG. 3 is a vertical cross-sectional view of the multi-core writing instrument in a writing state. FIG. 4 is a vertical cross-sectional view of the multi-core writing instrument in a writing state during refill switching. FIG. 5 is a vertical cross-sectional view of the multi-core writing instrument in a writing state after switching of refills. FIG. 6 is a vertical cross-sectional view of the rear axle. FIG. 7 is a perspective view of the operating member. FIG. 8 is a side view of the operating member. FIG. 9 is a perspective view of the rotating member. FIG. 10 is a vertical cross-sectional view of the rotating member. FIG. 11 is a perspective view of the slide cam. FIG. 12 is a vertical cross-sectional view of the slide cam.

The following describes in detail an embodiment of the present invention with reference to the drawings. Corresponding components are designated by the same reference symbols throughout the drawings.

Figure 1 is a perspective view of a multi-core writing instrument 1 according to an embodiment of the present invention. Also, Figure 2 is a vertical cross-sectional view of the multi-core writing instrument 1 in a non-writing state, Figure 3 is a vertical cross-sectional view of the multi-core writing instrument 1 in a writing state, Figure 4 is a vertical cross-sectional view of the multi-core writing instrument 1 in a writing state during refill switching, and Figure 5 is a vertical cross-sectional view of the multi-core writing instrument 1 in a writing state after refill switching.

The multi-core writing instrument 1 has a barrel 2, which is a cylindrical member formed into a cylindrical shape. The barrel 2 is composed of a front barrel 3, a center barrel 4, and a rear barrel 10. In addition, a plurality of refills 5, specifically two refills 5, are arranged in the barrel 2 as writing bodies with a writing part 5a at one end. The two refills 5 are referred to as refills 5A and 5B when distinguishing between them. Each of the two refills 5 is independently biased backward by a corresponding spring 6 as an elastic member. The multi-core writing instrument 1 further has an operating member 20, which is a first operating part, a rotating member 30, a slide cam 40, a knock member 50, which is a second operating part, a rotor 60, and a sliding top 70. In this specification, in the axial direction of the multi-core writing instrument 1, the writing part 5a side is defined as the "front" side, and the opposite side to the writing part 5a is defined as the "rear" side. Unless otherwise specified, the central axis or axial direction refers to the central axis or axial direction of the multi-core writing instrument 1.

The multi-core writing instrument 1 is a knock-type writing instrument in which the refill 5 appears and disappears from the barrel 2 by a knock operation that presses the knock member 50 forward. In other words, the refill 5, which is moving forward relatively, specifically the refill 5A in FIG. 2, appears and disappears from the end face of the barrel 2 by a knock operation that presses the knock member 50 forward.

Generally, knock-type writing instruments have a rotor. A protruding cam portion is provided on the outer peripheral surface of the rotor, and a protruding cam portion that cooperates with the cam portion of the rotor is provided on the inner peripheral surface of the barrel. By knocking, the cam portion of the rotor and the cam portion of the barrel are engaged or disengaged, thereby switching between a writing state and a non-writing state.

In this embodiment, a cam portion 11, which will be described later, is formed on the inner peripheral surface of the rear end of the rear barrel 10 of the barrel 2. The knock operation is performed by pressing the knock member 50 forward and moving the rotor 60 together with the knock member 50 forward to a predetermined position in the barrel 2. That is, in order for the cam portion (not shown) of the rotor 60 to engage with the cam portion 11 of the barrel 2, the rotor 60 is moved to a predetermined position where the rear end face of the cam portion of the rotor 60 is located at least axially forward of the front end face of the cam portion 11 of the barrel 2. After the rotor 60 has been moved to the predetermined position, the force applied to the knock member 50 is released, and the rotor 60 rotates and moves back slightly due to the biasing force of the spring 6, and the rear end face of the cam portion of the rotor 60 engages with the front end face of the cam portion 11 of the barrel 2, and the multi-core writing instrument 1 is in a writing state (FIG. 3).

In the writing state, when the knock member 50 is pressed forward by a knock operation and the rotor 60 is moved forward again to a predetermined position, the rear end face of the cam portion of the rotor 60 is disengaged from the front end face of the cam portion 11 of the barrel 2, and the rotor 60 rotates. When the force applied to the knock member 50 is then released, the biasing force of the spring 6 moves the rotor 60 further backward, and the multi-core writing instrument 1 returns to the non-writing state (Figure 2).

The configuration of the main components will be explained with reference to Figures 6 to 11 as appropriate.

Figure 6 is a vertical cross-sectional view of the rear barrel 10. In the assembled state of the multi-core writing instrument 1, the rear barrel 10 is arranged so that the upper side in Figure 6 is the rear side of the multi-core writing instrument 1. The rear barrel 10 is a cylindrical member formed in a cylindrical shape. A rectangular unevenness is formed on the front end surface of the rear barrel 10. The unevenness on the front end surface of the rear barrel 10 is fitted and joined with the unevenness (Figure 1) formed complementary to the rear end surface of the center barrel 4. A cam portion 11 is formed on the inner peripheral surface of the rear end of the rear barrel 10. The cam portion 11 is composed of a plurality of protrusions 12 extending in the axial direction, and as described above, engages or disengages with the cam portion of the rotor 60 during the knock operation. Two slide grooves 13 extending from the front end toward the rear and arranged opposite each other are formed on the inner peripheral surface of the rear barrel 10. The inner peripheral surface of the rear of the front end of the rear axle 10 is formed with a smaller diameter than the inner peripheral surface of the front end, and a first annular step portion 14 facing forward is formed. Also, a second annular step portion 15 facing forward is formed on the inner peripheral surface in front of the cam portion 11. A first through hole 16a located on the front side and a second through hole 16b located on the rear side are formed on the peripheral surface of the rear axle 10 along the axial direction.

7 is a perspective view of the operating member 20, and FIG. 8 is a side view of the operating member 20. In the assembled state of the multi-core writing instrument 1, the operating member 20 is arranged so that the upper side in FIG. 7 and FIG. 8 is the rear side of the multi-core writing instrument 1. The operating member 20 is a cylindrical member formed in a cylindrical shape. An operating protrusion 21 is formed on the outer peripheral surface of the front end of the operating member 20. On both sides of the operating protrusion 21 in the circumferential direction of the operating member 20, two slits 22 extending in parallel from the front end toward the rear are formed. On the peripheral surface of the operating member 20, a cam groove 23 is formed in a spiral shape around the central axis. The spiral cam groove 23 is formed clockwise from the vicinity of the rear end toward the front by approximately half a turn when the operating member 20 is viewed from the rear. On the peripheral surface of the operating member 20, one slit 24 extending from the rear end toward the front is formed.

9 is a perspective view of the rotating member 30, and FIG. 10 is a vertical cross-sectional view of the rotating member 30. In the assembled state of the multi-core writing instrument 1, the rotating member 30 is arranged so that the upper side in FIG. 9 and FIG. 10 is the rear side of the multi-core writing instrument 1. The rotating member 30 is composed of a cylindrical small diameter portion 31 located at the front side, a cylindrical large diameter portion 32 formed behind the small diameter portion 31, and a columnar sliding portion 33 formed behind the large diameter portion 32. One cam protrusion 34 is formed on the outer circumferential surface of the small diameter portion 31. The cross-sectional shape of the cam protrusion 34 is an ellipse or a rounded rectangle. The cam protrusion 34 is oriented so as to follow the extension direction of the cam groove 23 arranged as described later. The cam protrusion 34 may be circular. The insides of the large diameter portion 32 and the sliding portion 33 are equally separated by a partition wall 35 extending in the axial direction in order to arrange the two refills 5 at a distance from each other. Inside the large diameter portion 32, two insertion holes 36 are formed at symmetrical positions across the partition wall 35, and extend in the axial direction. A support surface 37 facing rearward is formed on the inner peripheral surface of each of the insertion holes 36. Two rail grooves 38, which are rectangular through-holes extending in the axial direction, are formed on the peripheral surface of the sliding portion 33, and are positioned symmetrical across the partition wall 35.

11 is a perspective view of the slide cam 40, and FIG. 12 is a vertical cross-sectional view of the slide cam 40. When the multi-core writing instrument 1 is assembled, the slide cam 40 is arranged so that the upper side in FIG. 11 is the rear side of the multi-core writing instrument 1. The slide cam 40 has an annular portion 41 formed in an annular shape around the central axis, and a claw-shaped claw portion 42. The edge of the claw portion 42 is formed with a flat surface 43 formed flat and a slanted end surface 44 formed obliquely. The flat surface 43 and the slanted end surface 44 of the claw portion 42 and the front end surface 45 of the annular portion 41 form a cam surface 46. Two slide protrusions 47 extending in the axial direction are formed on the outer peripheral surface of the annular portion 41. The two slide protrusions 47 are formed symmetrically around the central axis. The inner peripheral surface near the rear end of the annular portion 41 protrudes in an annular shape, thereby forming an annular support surface 48 facing rearward.

Next, the combination and arrangement of each part in the multi-core writing instrument 1 will be explained, mainly with reference to Figures 1 to 5.

The front shaft 3 is fitted to the front end of the center shaft 4. The rotating member 30 is arranged in the shaft tube 2 so that the front end surface of the small diameter portion 31 faces the rear end surface of the front shaft 3, and the rear end surface of the large diameter portion 32 of the rotating member 30 faces the first step portion 14 of the rear shaft 10. As a result, the rotating member 30 is arranged in the shaft tube 2 so that it can rotate around the central axis while its axial movement is restricted. The rear portion of the front shaft 3 is formed in a cylindrical shape having approximately the same outer diameter and inner diameter as the small diameter portion 32 of the rotating member 30. The operating member 20 is arranged over both the outer surface of the rear portion of the front shaft 3 and the outer surface of the small diameter portion 32 of the rotating member 30. At this time, the cam protrusion 34 of the rotating member 30 is arranged in the cam groove 23 of the operating member 20. In addition, the operating protrusion 21 of the operating member 20 protrudes to the outside of the shaft tube 2 through a window hole 4a formed on the circumferential surface of the center shaft 4. The window hole 4a is a rectangular through hole extending in the axial direction. The operation protrusion 21 abuts against the inner edge of the window hole 4a, restricting the forward and backward movement of the operation member 20 within a predetermined distance range and restricting the rotation of the operation member 20 around the central axis. When the operation member 20 is placed in the barrel 2, the slits 22 and 24 formed in the operation member 20 allow elastic deformation in the radial direction, making it easy to place.

Each of the two refills 5 is inserted into the corresponding insertion hole 36 of the rotating member 30 and separated by the partition wall 35. A sliding top 70 is inserted into the rear end of the refill 5, and the sliding top 70 is connected to the refill 5 by fitting. The sliding top 70 connected to the refill 5 fits into the rail groove 38 of the rotating member 30 and is arranged to be slidable in the axial direction without falling off. The rear end of the sliding part 33 of the rotating member 30 is received in the front part of the slide cam 40. Each of the slide protrusions 47 of the slide cam 40 is arranged in the corresponding slide groove 13 of the rear shaft 10. As a result, the slide cam 40 is arranged to be slidable in the axial direction without rotating around the central axis.

The spring 6 is disposed in the insertion hole 36 of the rotating member 30. At this time, the front end of the spring 6 is supported by the support surface 37 of the rotating member 30, and the rear end of the spring 6 abuts against the sliding top 70. As a result, the spring 6 urges the sliding top 70 backward, and in turn urges the refill 5 connected to the sliding top 70 backward. In addition, the rear end of the sliding top 70 abuts against the cam surface 46 of the slide cam 40. Therefore, the spring 6 also urges the slide cam 40 backward via the sliding top 70. In the non-writing state of the multi-core writing instrument 1 (FIG. 2), the rearward movement of the slide cam 40 urged backward is restricted by the support surface 48 of the slide cam 40 abutting against the front end surface of the rotor 60, or by the rear end surface of the slide cam 40 abutting against the second step portion 15 of the rear shaft 10. In addition, when the multi-core writing instrument 1 is in the writing state (Figure 3), the rearward movement of the rearwardly biased slide cam 40 is restricted by the support surface 48 of the slide cam 40 abutting against the front end surface of the rotor 60.

Next, the operation of the multi-core writing instrument 1 will be explained.

As described above, in the multi-core writing instrument 1, the operating member 20, which is the first operating part, specifically the operating protrusion 21, is provided so as to be movable in the front-rear direction relative to the barrel 2. The multi-core writing instrument 1 is configured so that the operating member 20 and the rotating member 30 cooperate to rotate the rotating member 30 in response to the front-rear movement of the operating member 20, thereby moving one of the multiple refills 5 forward. In other words, the front-rear movement of the operating member 20 is converted into the rotational movement of the rotating member 30, and the rotational movement of the rotating member 30 is converted into the front-rear movement of the refill 5.

2 and 3, the refill 5A is in a position further forward than the refill 5B. That is, the sliding top 70 to which the refill 5A is connected is disposed on the flat surface 43 of the claw portion 42 on the cam surface 46 of the slide cam 40. On the other hand, the sliding top 70 to which the refill 5B is connected is disposed on the front end surface 45 of the annular portion 41 on the cam surface 46 of the slide cam 40. Therefore, the refill 5A is relatively further forward than the refill 5B. Therefore, when the knock member 50, which is the second operating part, is knocked in the non-writing state shown in FIG. 2, the refill 5A and the refill 5B advance together with the rotor 60 and the slide cam 40. As a result, only the refill 5A, which has advanced relatively, protrudes from the barrel 2, and the writing state is established (FIG. 3). Note that the knock operation does not move the operating member 20 and the rotating member 30 in the axial direction.

In the state shown in FIG. 3, the operation protrusion 21 of the operating member 20 is disposed at the front end in the window hole 4a, and the cam protrusion 34 of the rotating member 30 is disposed at the rear end in the cam groove 23 of the operating member 20. In this state, when the operation protrusion 21 of the operating member 20 is moved backward, the cam protrusion 34 moves relatively forward along the spiral track of the cam groove 23. This causes the rotating member 30 to rotate around the central axis (FIG. 4). At this time, the refill 5 and the sliding top 70 rotate around the central axis together with the rotating member 30 while being biased backward by the spring 6. As a result, each of the sliding tops 70 moves in the circumferential direction along the cam surface 46 of the slide cam 40. Therefore, the sliding top 70 to which the refill 5A is connected moves from the flat surface 43 of the claw portion 42 along the inclined end surface 44 toward the front end surface 45 of the annular portion 41 on the cam surface 46 of the slide cam 40. On the other hand, the sliding top 70 to which the refill 5B is connected moves on the cam surface 46 of the slide cam 40 from the front end surface 45 of the annular portion 41 along the inclined end surface 44 toward the flat surface 43 of the claw portion 42.

When the operating protrusion 21 of the operating member 20 is moved further rearward until it reaches the rear end in the window hole 4a, the cam protrusion 34 of the rotating member 30 reaches the front end in the cam groove 23 of the operating member 20. This completes the rotation of the rotating member 30 around the central axis, specifically, a 180-degree rotation. That is, the sliding top 70 to which the refill 5A is connected is disposed on the front end surface 45 of the annular portion 41 on the cam surface 46 of the slide cam 40. On the other hand, the sliding top 70 to which the refill 5B is connected is disposed on the flat surface 43 of the claw portion 42 on the cam surface 46 of the slide cam 40. Therefore, the refill 5B protrudes from the barrel 2 relatively further forward than the refill 5A, and is in a writing state (Fig. 5).

When writing again with refill 5A in the state shown in FIG. 5, the operating protrusion 21 of the operating member 20 is moved forward. By moving the operating protrusion 21 backward, the cam protrusion 34 moves relatively backward along the spiral trajectory of the cam groove 23. This causes the rotating member 30 to rotate around the central axis in the opposite direction to the previous rotation (FIG. 4). As a result, refill 5A moves forward relatively more than refill 5B and protrudes from the barrel 2, entering the writing state (FIG. 3). Note that while the switching of refills 5 in the writing state of the multi-core writing instrument 1 has been described with reference to FIGS. 3 to 5, the switching of refills 5 can also be performed in a similar manner when the multi-core writing instrument 1 is not in a writing state.

Next, the operation of the multi-core writing instrument 1 by a user will be specifically described. A user usually holds the center shaft 4 of the multi-core writing instrument 1 with the thumb, index finger, and middle finger and writes. At this time, the multi-core writing instrument 1 is held so that the operating protrusion 21 of the operating member 20 is positioned between the thumb and index finger. When switching refills, the user supports the multi-core writing instrument 1 with the index finger and middle finger and uses the thumb to slide or flick the operating protrusion 21 forward or backward. After that, the thumb is returned to its original position and the multi-core writing instrument 1 is held, allowing writing to be performed.

Therefore, the multi-core writing instrument 1 allows the user to easily switch between refills to be used. It is particularly preferable that the first operating portion, i.e., the operating member 20 or operating protrusion 21, is located in the front half of the barrel 2 so that it is easy to operate with the thumb. Furthermore, the multi-core writing instrument 1 allows the user to switch between refills to be used without having to stop writing and change the grip of the barrel 2. Furthermore, the user can easily determine whether the refill 5A or the refill 5B is in the advanced position by looking at or feeling the position of the operating protrusion 21 within the window hole 4a.

The user can determine whether the refill 5A or the refill 5B is in the forward position by checking the inside of the barrel 2 through the first through hole 16a and the second through hole 16b formed in the rear barrel 10. To do this, a sliding top 70 colored the same color as the ink contained in the connected refill 5 is used. For example, in the state shown in FIG. 2, the sliding top 70 of the refill 5A is visible through the first through hole 16a and the second through hole 16b. Therefore, the user can determine that the refill 5A protrudes from the barrel 2 when performing a knock operation in this state. Also, in the writing state shown in FIG. 3, the sliding top 70 of the refill 5A is visible only through the first through hole 16a. Therefore, the user can determine that the refill 5A protrudes from the barrel 2. On the other hand, in the state shown in FIG. 5, the sliding top 70 of the refill 5B is visible only through the first through hole 16a. Therefore, the user can tell that the refill 5B is protruding from the barrel 2.

In the above embodiment, the multi-core writing instrument 1 is a knock-type writing instrument, but it may be configured as a writing instrument that can switch the refill 5 protruding from the barrel 2 without performing a knock operation. That is, the knock member 50 and the rotor 60 are eliminated from the multi-core writing instrument 1, and the slide cam 40 is fixed at the position shown in Figures 3 to 5. In this case, the slide cam 40 may be formed integrally with the barrel 2. In the multi-core writing instrument configured in this manner, as shown in Figure 4, when the operation protrusion 21 is placed at the middle position in the front-rear direction of the window hole 4a, the multi-core writing instrument can be in a non-writing state. When the operation protrusion 21 is moved forward from this state, the refill 5A can be protruded from the barrel 2, and when the operation protrusion 21 is moved backward, the refill 5B can be protruded from the barrel 2, and the multi-core writing instrument can be in a writing state.

In addition, in the above-described embodiment, the cam groove 23 is formed in the operating member 20, and the cam protrusion 34 is formed in the rotating member 30, but a cam protrusion protruding radially inward may be formed in the operating member, and a cam groove may be formed in the rotating member. That is, as long as a cam groove is formed in one of the first operating part and the rotating member, and a cam protrusion is formed in the other of the first operating part and the rotating member, and the first operating part and the rotating member cooperate with each other by the cam groove and the cam protrusion working together, any configuration may be adopted for the shape of the cam groove, as long as the forward and backward movement of the first operating part is converted into rotational movement of the rotating member.

In the above-mentioned embodiment, the multi-core writing instrument 1 has two refills 5, but it may have three or more refills. The number of insertion holes of the rotating member, the shape of the partition, and the shape of the cam surface of the slide cam can be arbitrarily configured according to the number of refills. That is, the position and shape of the claw portion of the cam surface of the slide cam can be configured so that one of the multiple refills advances by cooperation between the multiple refills and the cam surface in response to the rotation of the rotating member. At this time, the position of the operation protrusion and the protruding refill, that is, the position of the cam protrusion in the cam groove and the protruding refill, are in a corresponding relationship. In the above-mentioned embodiment, since there were two refills, when the operation protrusion 21 is at the front end and the rear end in the window hole 4a, one refill is configured to protrude from the barrel 2. For example, in the case of three refills, when the operation protrusion 21 is at the front end, the center, or the rear end in the window hole 4a, one of the three refills can be configured to protrude.

The refill 5 described above may be a ballpoint pen refill, or may be other types of refills such as mechanical pencils, marking pens, touch pens, erasers, or friction bodies. In addition, the entire operating member 20, which is the first operating part, or a part of the operating member 20 may be bonded or molded in two colors, so that the operating member 20 serves as an erasing member that erases handwriting made by the refill 5. In addition, the entire knock member 50, which is the second operating part, or a part of the knock member 50 may be bonded or molded in two colors, so that the knock member 50 serves as an erasing member that erases handwriting made by the refill 5. In addition, other parts of the multi-core writing instrument 1, such as the front end of the front shaft 3, may be used as an erasing member.

For the refill, a ballpoint pen containing thermochromic ink, a mechanical pencil containing a thermochromic core, etc. can be used. In this case, the multi-core writing instrument 1 is a thermochromic writing instrument, and the handwriting can be thermochromic due to the frictional heat generated when rubbed by the friction body, which is the erasing member. Here, the thermochromic ink refers to an ink that has the property of maintaining a certain color (first color) at room temperature (e.g., 25°C), changing to another color (second color) when heated to a certain temperature (e.g., 60°C), and then returning to the original color (first color) when cooled to a certain temperature (e.g., -5°C). In a writing instrument using thermochromic ink, the second color is made colorless, and the process of heating up a line written in the first color (e.g., red) to make it colorless is referred to as "erasing" here. Therefore, the friction body as the erasing part rubs against the writing surface on which the drawn lines are drawn, generating frictional heat, which changes the drawn lines to colorless, i.e., erases them. Of course, the second color may be a color other than colorless.

The thermochromic microencapsulated pigment that serves as the thermochromic coloring material is not particularly limited as long as it has the ability to change color due to heat such as frictional heat, for example, from colored to colorless, from colored to colored, or from colorless to colored, and various types can be used, and examples of such materials include microencapsulated thermochromic compositions that contain at least a leuco dye, a color developer, and a color change temperature regulator.

The leuco dyes that can be used are not particularly limited, so long as they are electron-donating dyes that function as color-developing agents. Specifically, in order to obtain inks with excellent color-developing properties, conventionally known dyes such as triphenylmethane, spiropyran, fluoran, diphenylmethane, rhodamine lactam, indolylphthalide, and leucoauramine can be used alone (one type) or in a mixture of two or more types (hereinafter simply referred to as "at least one type").

Specifically, 6-(dimethylamino)-3,3-bis[4-(dimethylamino)phenyl]-1(3H)-isobenzofuranone, 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide, 3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)- 4-Azaphthalide, 1,3-dimethyl-6-diethylaminofluoran, 2-chloro-3-methyl-6-dimethylaminofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-xylidinofluoran, 2-(2-chloroanilino)-6-dibutylaminofluoran, 3,6-dimethoxyfluoran, 3,6-di -n-butoxyfluoran, 1,2-benz-6-diethylaminofluoran, 1,2-benz-6-dibutylaminofluoran, 1,2-benz-6-ethylisoamylaminofluoran, 2-methyl-6-(N-p-tolyl-N-ethylamino)fluoran, 2-(N-phenyl-N-methylamino)-6-(N-p-tolyl-N-ethylamino)fluoran, 2-(3'-trifluoromethylanilino)-6-diethylamino Nofluoran, 3-chloro-6-cyclohexylaminofluoran, 2-methyl-6-cyclohexylaminofluoran, 3-di(n-butyl)amino-6-methoxy-7-anilinofluoran, 3,6-bis(diphenylamino)fluoran, methyl-3',6'-bisdiphenylaminofluoran, chloro-3',6'-bisdiphenylaminofluoran, 3-methoxy-4-dodecoxystyrinoquinoline, etc.

These leuco dyes have a lactone skeleton, a pyridine skeleton, a quinazoline skeleton, a bisquinazoline skeleton, etc., and color is generated by opening these skeletons (rings).

The color developer that can be used is a component that has the ability to cause the leuco dye to develop color, and examples of such compounds include phenolic resin compounds, salicylic acid metal chlorides, salicylic acid resin metal salt compounds, and solid acid compounds.

Specifically, o-cresol, tertiary butyl catechol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-phenylphenol, hexafluorobisphenol, n-butyl p-hydroxybenzoate, n-octyl p-hydroxybenzoate, resorcin, dodecyl gallate, 2,2-bis(4'-hydroxyphenyl)propane, 4,4-dihydroxydiphenyl sulfone, 1,1-bis(4'-hydroxyphenyl)ethane, 2,2-bis(4'-hydroxy-3-methylphenyl)propane, bis(4-hydroxyphenyl)sulfide, 1-phenyl-1,1-bis( 1,1-bis(4'-hydroxyphenyl)ethane, 1,1-bis(4'-hydroxyphenyl)-3-methylbutane, 1,1-bis(4'-hydroxyphenyl)-2-methylpropane, 1,1-bis(4'-hydroxyphenyl)n-hexane, 1,1-bis(4'-hydroxyphenyl)n-heptane, 1,1-bis(4'-hydroxyphenyl)n-octane, 1,1-bis(4'-hydroxyphenyl)n-nonane, 1,1-bis(4'-hydroxyphenyl)n-decane, 1 , 1-bis(4'-hydroxyphenyl)n-dodecane, 2,2-bis(4'-hydroxyphenyl)butane, 2,2-bis(4'-hydroxyphenyl)ethyl propionate, 2,2-bis(4'-hydroxyphenyl)-4-methylpentane, 2,2-bis(4'-hydroxyphenyl)hexafluoropropane, 2,2-bis(4'-hydroxyphenyl)n-heptane, 2,2-bis(4'-hydroxyphenyl)n-nonane, etc. are at least one of them.

The amount of developer used can be selected according to the desired color density and is not particularly limited, but it is usually preferable to select an amount within the range of about 0.1 to 100 parts by weight per 1 part by weight of the leuco dye described above.

The discoloration temperature regulator that can be used is a substance that controls the discoloration temperature in the color development of the leuco dye and the color developer. The discoloration temperature regulator that can be used is any of those that are conventionally known. Specific examples include alcohols, esters, ketones, ethers, acid amides, azomethines, fatty acids, and hydrocarbons.

More specifically, at least one of bis(4-hydroxyphenyl)phenylmethane dicaprylate (C ₇ H ₁₅ ), bis(4-hydroxyphenyl)phenylmethane dilaurate (C ₁₁ H ₂₃ ), bis(4-hydroxyphenyl)phenylmethane dimyristate (C ₁₃ H ₂₇ ), bis(4-hydroxyphenyl)phenylethane dimyristate (C ₁₃ H ₂₇ ), bis(4-hydroxyphenyl)phenylmethane dipalmitate (C ₁₅ H ₃₀ ), bis(4-hydroxyphenyl)phenylmethane dibehenate (C ₂₁ H ₄₃ ), bis(4-hydroxyphenyl)phenylethylhexylidene dimyristate (C ₁₃ H ₂₇ ) and the like can be mentioned.

The amount of the discoloration temperature regulator used can be appropriately selected depending on the desired hysteresis width and color density at the time of color development, and is not particularly limited, but it is usually preferable to use it in the range of about 1 to 100 parts by weight per 1 part by weight of the leuco dye.

The thermochromic microencapsulated pigment can be produced by microencapsulating a thermochromic composition containing at least the above leuco dye, color developer, and color change temperature regulator so that the average particle size is 0.2 to 5 μm. Examples of microencapsulation methods include interfacial polymerization, interfacial polycondensation, in situ polymerization, liquid curing coating, phase separation from an aqueous solution, phase separation from an organic solvent, melt dispersion cooling, air suspension coating, and spray drying, and can be appropriately selected depending on the application.

For example, in the phase separation method from an aqueous solution, the leuco dye, developer, and discoloration temperature regulator are heated and melted, then added to an emulsifier solution, heated and stirred to disperse them into oil droplets, and then a resin raw material is gradually added as a capsule membrane agent, such as an amino resin solution or an isocyanate resin solution, and the mixture is allowed to react and then filtered to produce the desired thermochromic microcapsule pigment.

The content of these leuco dyes, color developers, and color change temperature regulators varies depending on the type of leuco dyes, color developers, and color change temperature regulators used, the microencapsulation method, etc., but the mass ratio is 0.1 to 100 parts of color developer and 1 to 100 parts of color change temperature regulator per 1 part of the dye. The mass ratio of the capsule membrane agent to the capsule contents is 0.1 to 1.

The thermochromic microcapsule pigment can be set to an appropriate temperature for each color's color development temperature (for example, color development at 0°C or higher) and color loss temperature (for example, color loss at 50°C or higher) by appropriately combining the types and amounts of the above-mentioned leuco dye, color developer, and color change temperature regulator, and it is preferable that the color changes from colored to colorless due to heat such as frictional heat.

In the case of thermochromic microcapsule pigments, in order to further improve the line density, storage stability, and writing ability, it is preferable that the wall film is formed of a urethane resin, a urea/urethane resin, an epoxy resin, or an amino resin. Examples of urethane resins include compounds of isocyanate and polyol. Examples of epoxy resins include compounds of epoxy resin and amine. Examples of amino resins include melamine resin, urea resin, and benzoguanamine resin. The thickness of the wall film of the microcapsule color material is appropriately determined depending on the required wall film strength and line density.

The average particle size of the thermochromic microencapsulated pigment is preferably 0.2 to 5 μm, and more preferably 0.3 to 3 μm, in terms of coloring ability, color development, ease of fading, stability, fluidity in the ink, suppression of adverse effects on writing, and compatibility with the photochromic microencapsulated pigment described below. The "average particle size" specified here is the value obtained by measuring the average particle size (50% diameter) (refractive index 1.8) using a particle size analyzer [Microtrac HRA9320-X100 (manufactured by Nikkiso)].

If the average particle size is less than 0.2 μm, sufficient line density cannot be obtained, while if it exceeds 5 μm, it is undesirable because it deteriorates writing properties, reduces the dispersion stability of the thermochromic microencapsulated pigment, and is prone to ink back caused by vibration. Furthermore, the 90% diameter is 8 μm or less, preferably 6 μm or less. If a certain proportion of particles with large diameters are present, the above-mentioned effects tend to become more pronounced. Note that the microencapsulated pigment that falls within the above-mentioned average particle size range (0.2 to 5 μm) varies depending on the microencapsulation method, but in a phase separation method from an aqueous solution, etc., it can be prepared by appropriately combining the stirring conditions when manufacturing the microencapsulated pigment.

The specific gravity of the thermochromic microencapsulated pigment is in the range of 0.9 to 1.3, preferably 1.0 to 1.2. If the specific gravity is outside this range, the dispersion stability of the microencapsulated pigment is likely to decrease. Furthermore, microencapsulated pigments with a specific gravity exceeding 1.3 are prone to ink back caused by vibration.

In addition to the thermochromic microencapsulated pigment, the aqueous ink composition for writing instruments may contain water (tap water, purified water, distilled water, ion-exchanged water, pure water, etc.) as the solvent as the remainder, and may also contain water-soluble organic solvents, thickeners, lubricants, rust inhibitors, preservatives, or antibacterial agents as appropriate, depending on the application of each writing instrument (ballpoint pen, marking pen, etc.), within the range that does not impair the effects of the agent.

Examples of water-soluble organic solvents that can be used include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 3-butylene glycol, thiodiethylene glycol, and glycerin, as well as ethylene glycol monomethyl ether and diethylene glycol monomethyl ether, which can be used alone or in combination.

Of these, it is preferable to use glycerin to prevent ink solidification at the writing area due to the ink bag, and the amount added is preferably 1 to 10% by mass of the total amount of ink. The mechanism of action of glycerin is unknown, but it is presumed to have the effect of reducing the cohesive force between the pigment and ink components in a dry state.

As the thickener that can be used, for example, at least one selected from the group consisting of synthetic polymers, cellulose, and polysaccharides is preferable. Specific examples include gum arabic, tragacanth gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, xanthan gum, welan gum, succinoglycan, diutan gum, dextran, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, starch glycolic acid and its salts, propylene glycol alginate, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, polyacrylic acid and its salts, carboxyvinyl polymer, polyethylene oxide, copolymer of vinyl acetate and polyvinylpyrrolidone, crosslinked acrylic acid polymer and its salts, non-crosslinked acrylic acid polymer and its salts, styrene acrylic acid copolymer and its salts, etc.

Of these, it is preferable to use polysaccharides. Due to their rheological properties, polysaccharides tend to be less susceptible to the effects of vibration on fluidity, and are less likely to cause problems such as poor writing caused by ink bag. Xanthan gum is particularly preferable, as it provides an excellent balance with other properties required of writing instrument inks.

Lubricants include fatty acid esters of polyhydric alcohols, which are also used as surface treatment agents for pigments, higher fatty acid esters of sugars, polyoxyalkylene higher fatty acid esters, alkyl phosphate esters, alkyl sulfonates of higher fatty acid amides, alkyl aryl sulfonates, polyalkylene glycol derivatives, fluorine-based surfactants, polyether-modified silicones, etc. Rust inhibitors include benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, saponins, etc. Preservatives or antibacterial agents include phenol, sodium omadine, sodium benzoate, benzimidazole-based compounds, etc.

This aqueous ink composition for writing instruments can be produced by a conventional method, for example, by blending the thermochromic and photochromic microencapsulated pigments and the other aqueous components in predetermined amounts and stirring and mixing them with a stirrer such as a homomixer or a disperser. If necessary, coarse particles in the ink composition may be removed by filtration or centrifugation.

The viscosity value of the aqueous ink composition for writing instruments is preferably 500 to 2000 mPa·s at 25° C. and a shear rate of 3.83/s, and 20 to 100 mPa·s at a shear rate of 383/s. By setting the viscosity within the above range, an ink having excellent writing properties and stability over time can be obtained. Furthermore, the non-Newtonian viscosity index n calculated by the viscosity formula S=αD ⁿ (where 1>n>0) (S is shear stress (dyn/cm ² ), D is shear rate (s ⁻¹ ), and α is a non-Newtonian viscosity coefficient) is preferably 0.2 to 0.6. By setting the non-Newtonian viscosity index n within the above range in addition to the above viscosity range, it is possible to appropriately set the fluidity of the ink against vibration, and it is possible to prevent the occurrence of ink back.

The surface tension of the aqueous ink composition for writing instruments is preferably 25 to 45 mN/m, and more preferably 30 to 40 mN/m. Within this range, the balance between the wettability of the inside of the pen tip and the ink is appropriate, making it possible to prevent the occurrence of ink back.

In the refill, an ink follower may be placed immediately behind the ink. The material constituting the follower may be composed of at least a non-volatile or low-volatility organic solvent and a thickener. The non-volatile or low-volatility organic solvent used in the ink follower is used as the base oil for the ink follower, and liquid paraffin is used, for example. Mineral oil and chemically synthesized oil are used for the liquid paraffin, and polybutene, poly-α-olefin, ethylene α-olefin oligomer, etc. can be used as the chemically synthesized oil.

Specific examples of mineral oils that can be used include commercially available Diana Process Oil NS-100, PW-32, PW-90, NR-68, and AH-58 (manufactured by Idemitsu Kosan Co., Ltd.).

Specific examples of polybutenes that can be used include commercially available products such as Nissan Polybutene 200N, Polybutene 30N, Polybutene 10N, Polybutene 5N, Polybutene 3N, Polybutene 015N, Polybutene 06N, and Polybutene 0N (all manufactured by Nippon Oil & Fats Corporation), Polybutene HV-15 (manufactured by Nippon Petrochemical Industry Co., Ltd.), and 35R (manufactured by Idemitsu Kosan Co., Ltd.).

Specific examples of poly-α-olefins that can be used include commercially available barrel process oils P-26, P-46, P-56, P-150, P-350, P-1500, P-2200, (P-10000, P-37500) (manufactured by Matsumura Oil Co., Ltd.).

Specific examples of ethylene α-olefin oligomers that can be used include commercially available products such as LUCANT HC-10, HC-20, HC-100, HC-150, (HC-600, HC-2000) (all manufactured by Mitsui Chemicals, Inc.).

These non-volatile or low-volatile organic solvents can be used alone or in combination of two or more.

Examples of thickeners used in the ink follower include calcium salts of phosphate esters, fine silica particles, block copolymers of polystyrene-polyethylene/butylene rubber-polystyrene, block copolymers of polystyrene-polyethylene/propylene rubber-polystyrene, hydrogenated styrene-butadiene rubber, block copolymers of styrene-ethylenebutylene-olefin crystals, block copolymers of olefin crystals-ethylenebutylene-olefin crystals, and acetoalkoxyaluminum dialkylates, and these can be used alone or in combination of two or more.

Preferred commercially available calcium salts of phosphate esters that can be used include Crodax DP-301LA (manufactured by Croda Japan Co., Ltd.). Usable fine particle silica includes hydrophilic fine particle silica and hydrophobic fine particle silica. Preferred commercially available hydrophilic silica products include AEROSIL-300 and AEROSIL-380 (manufactured by Nippon Aerosil Co., Ltd.), and preferred commercially available hydrophobic silica products include AEROSIL-974D and AEROSIL-972 (manufactured by Nippon Aerosil Co., Ltd.).

Preferable commercially available polystyrene-polyethylene/butylene rubber-polystyrene block copolymers include Kraton GFG-1901X and Kraton GG-1650 (both manufactured by Shell Japan), Septon 8007 and Septon 8004 (both manufactured by Kuraray Co., Ltd.), etc. Preferable commercially available polystyrene-polyethylene/propylene rubber-polystyrene block copolymers include Kraton GG-1730 (manufactured by Shell Japan), Septon 2006 and Septon 2063 (both manufactured by Kuraray Co., Ltd.), etc.

Preferred commercially available hydrogenated styrene-butadiene rubbers include DYNARON 1320P, DYNARON 1321P (both manufactured by JSR Corporation), Tuftec H1041, and Tuftec H1141 (both manufactured by Asahi Chemical Industry Co., Ltd.).

Preferred commercially available styrene-ethylenebutylene-olefin crystalline block copolymers include DYNARON 4600P (manufactured by JSR Corporation), and preferred commercially available olefin crystalline-ethylenebutylene-olefin crystalline block copolymers include DYNARON 6200P and DYNARON 6201B (manufactured by JSR Corporation).

Preferred commercially available acetoalkoxyaluminum dialkylates include PLENACT AL-M (manufactured by Ajinomoto Fine-Techno Co., Ltd.).

Among these thickeners, in order to further exert the effects of the present invention, it is preferable to use thermoplastic olefin-based elastomers such as styrene-ethylenebutylene-olefin crystalline block copolymers and olefin crystalline-ethylenebutylene-olefin crystalline block copolymers.

Furthermore, in order to obtain an ink follower that prevents the occurrence of ink back, it is preferable that the average tan δ value measured for each frequency while exponentially increasing in the frequency range of 1 to 63 rad/s is 1.0 or more, and more preferably 1.7 to 3.4.

Here, tan δ is a value that means the loss modulus/storage modulus, and it has been known in the past that the average tan δ value measured for each frequency while exponentially increasing in the frequency range "1 to 63 rad/s" is preferably 1.0 or less. In the present invention, by making the average tan δ value measured for each frequency in the above 1 to 63 rad/s 1.0 or more, it becomes possible to absorb vibrations and prevent the occurrence of ink back.

Materials that can be used to form the friction body include thermosetting rubbers such as silicone rubber, nitrile rubber, ethylene propylene rubber, and ethylene propylene diene rubber, as well as thermoplastic elastomers such as styrene-based elastomers, olefin-based elastomers, polyester-based elastomers, and urethane-based elastomers, as well as mixtures of two or more rubber-based materials and mixtures of rubber-based materials and synthetic resins. These materials are configured to produce a Taber abrasion amount of less than 25 mg on the abrasion wheel CS-17 of a Taber abrasion tester under a load of 9.8 N and 1000 rpm in an abrasion test (ASTM D1044) specified in JIS K7204, to form the friction body.

Alkyl sulfonic acid phenyl ester and cyclohexane dicarboxylic acid ester may be added to the material of the friction body. By including alkyl sulfonic acid phenyl ester and cyclohexane dicarboxylic acid ester in the friction body, it becomes possible to erase handwriting without damaging the paper surface and without blurring the printed characters. Furthermore, it is preferable that the friction body has a durometer D hardness of 30 or more as specified in JIS K6203. This ensures a predetermined hardness and enables a more stable rubbing operation. The friction body can also be used as a touch pen or a stylus pen, and may be made conductive.

The friction body is preferably colored with a color having a lower brightness value than the color of the thermochromic ink contained in the refill. In other words, if the thermochromic ink of the multi-core writing instrument 1 is transferred to the surface of the friction body without discoloring during use of the friction body, the transfer of the thermochromic ink can be made less noticeable. In particular, by making the color of the friction body black or having a brightness value of 2.5 or less, it is possible to make the stains on the surface of the friction body that occur during use less noticeable.

The brightness value is measured using the Munsell color system with a measuring device such as a general-purpose color difference meter (TC-8600A, manufactured by Tokyo Denshoku Co., Ltd.), the brightness value of the friction body is measured on the surface, and the brightness value of the thermochromic ink is obtained by measuring the ink on a line drawn on a paper surface (old JIS P3201; wood-free paper made from 100% chemical pulp, basis weight range 40-157 g/m2, whiteness 75.0% or more) at a writing speed of 4.5 m/min with a pitch interval of 0.1 mm.

REFERENCE SIGNS LIST 1 Multi-core writing implement 2 Barrel 3 Front barrel 4 Center barrel 5 Refill 6 Spring 10 Rear barrel 20 Operation member 21 Operation protrusion 23 Cam groove 30 Rotation member 34 Cam protrusion 40 Slide cam 50 Knock member 60 Rotor 70 Sliding piece

Claims (1)

The writing pen includes a barrel, a first operating section that is movable in a front-rear direction relative to the barrel, a plurality of writing bodies, and a rotating member that is rotatable about a central axis relative to the barrel while holding the plurality of writing bodies,
The first operating unit and the rotating member cooperate to rotate the rotating member in response to the forward and backward movement of the first operating unit, so that one of the plurality of writing bodies advances according to the position of the first operating unit in the forward and backward direction;
The first operating portion is disposed in a front half of the barrel,
A cam groove is formed on one of the first operation portion and the rotating member, and a cam protrusion is formed on the other of the first operation portion and the rotating member, the cam groove and the cam protrusion cooperate to rotate the rotating member, the cam groove is formed in a spiral shape around a central axis ,
A multi-core writing instrument further comprising a second operating portion, wherein a knock operation for pressing the second operating portion forward causes the advanced writing body to appear and disappear relative to the barrel .

Images