Writing implement

Abstract

A multi-lead writing implement 1 includes: a shaft cylinder 4; a plurality of ballpoint pen refills 6 which are housed in the shaft cylinder 4; first knock members 20 which are connected to the plurality of ballpoint pen refills 6 and are provided with operation parts projecting radially outward from the side face of the shaft cylinder 4; and a plurality of display parts 31 which are provided to the first knock members 20 so as to be visible from the front in the axial direction and not to be visible from the rear in the axial direction.

Description

writing implements

[0001] The present invention relates to a writing instrument, and more particularly to a multi-core writing instrument with multiple refills.

[0002] A multi-core writing instrument is known that includes a barrel, a plurality of refills housed in the barrel, a plurality of knocking members connected to each of the plurality of refills and each having an operating portion that protrudes radially outward from the side of the barrel, and a display portion provided on each of the knocking members (for example, Patent Document 1). The multi-core writing instrument described in Patent Document 1 is configured so that the display portion is colored to match the color of the ink housed in the refill, and the ink in the refill can be identified by visually checking the display portion.

[0003] The knock member of the multi-core writing instrument described in Patent Document 1 is formed by two-color molding of an embedded portion as a primary molded body and a covering portion as a secondary molded body. A part of the embedded portion serves as an indicator, that is, the indicator protrudes radially outward from the central axis of the multi-core writing instrument when the knock member is disposed in the barrel. As a result, the indicator can be seen from any angle in the axial direction of the multi-core writing instrument, from the front, rear, and side.

[0004] Japanese Patent Application Laid-Open No. 2022-112467

[0005] Generally, writing instruments are often displayed in stores for sale, and stored at home or elsewhere, with the writing section facing vertically downward. When a multi-core writing instrument is displayed or stored for an extended period of time, there is a risk that dust that falls due to gravity will adhere to the rear of the display section. Furthermore, when using a multi-core writing instrument, users often perform a knocking operation by pressing the rear of the knock member with their fingers and pushing the knock member forward. Therefore, there is a risk that sebum and other particles from the fingers will adhere to the display section, causing it to become dirty. The adhesion of dust and dirt can make the display section difficult to see, and in some cases, can lead to misinterpretation of the information displayed by the display section.

[0006] An object of the present invention is to provide a writing instrument having a display portion that is resistant to dirt.

[0007] According to one aspect of the present invention, there is provided a writing instrument comprising a barrel, at least one refill housed in the barrel, at least one knock member connected to the at least one refill and having an operating portion protruding radially outward from a side surface of the barrel, and at least one display portion provided on the at least one knock member so as to be visible from the axial front but not from the axial rear. Preferably, the writing instrument is a multi-core writing instrument equipped with a plurality of refills.

[0008] The operating unit may have a top that protrudes most radially outward, and the display unit may be located closer to the front than the top. The display unit may be formed as a protrusion that protrudes from a surface of the knock member. The pen may further include a clip member, and the at least one knock member may be configured to be engageable with the clip member, and a rear end of the at least one knock member engaged with the clip member may protrude rearward via the clip member. The at least one refill may have a first refill capable of writing with thermochromic ink and a second refill capable of writing with other types of ink than thermochromic ink, and may further include a first erasing member capable of erasing writing with the first refill, a second erasing member capable of erasing writing with the second refill, and a cover member engageable with the barrel, and one of the first erasing member or the second erasing member may be disposed at the rear end of the barrel and covered by the cover member. The multi-core writing instrument may further include a weight disposed within the barrel between 20 mm from the tip of the refill and half the length of the multi-core writing instrument when in a writing state, such that the center of gravity of the multi-core writing instrument is located between 20 mm from the tip of the refill and half the length of the multi-core writing instrument, and the weight of the multi-core writing instrument between 20 mm from the tip of the refill and half the length of the multi-core writing instrument is 50% or more of the total weight of the multi-core writing instrument. The barrel may be a resin molded product, and at least a portion of the outer surface of the barrel may have a leather-grained pattern. The at least one refill may have multiple refills, each of which has a writing part, and the shape, color, pattern, and gloss of the writing part may differ depending on the type or color of writing with the multiple refills. The writing instrument may have a holding member at the rear end capable of holding an item. The item may be a pick. The at least one refill may have a writing part, and the barrel or the writing part may be configured so that, in a writing state, an imaginary tangent at the front edge of the outer peripheral surface of the barrel passes through the writing implement.

[0009] According to the aspects of the present invention, a common effect is achieved in that a writing instrument having a display portion that is resistant to dirt is provided.

[0010] FIG. 1 is a perspective view of a multi-core writing instrument according to an embodiment of the present invention. FIG. 2 is a front view of the multi-core writing instrument of FIG. 1, as seen from the front in the axial direction. FIG. 3 is a rear view of the multi-core writing instrument of FIG. 1, as seen from the rear in the axial direction. FIG. 4 is a cross-sectional view of the multi-core writing instrument taken along line A-A in FIG. 2. FIG. 5 is a cross-sectional view of the multi-core writing instrument taken along line B-B in FIG. 2. FIG. 6 is a perspective view of a first knock member. FIG. 7 is a side view of the first knock member. FIG. 8 is a vertical cross-sectional view of the first knock member. FIG. 9 is a vertical cross-sectional view of a mold after primary molding in two-color molding of the first knock member. FIG. 10 is a vertical cross-sectional view of a mold after secondary molding in two-color molding of the first knock member. FIG. 11 is a side view of a second knock member equipped with a clip member. FIG. 12 is an exploded perspective view of the second knock member. FIG. 13 is another exploded perspective view of the second knock member. FIG. 14 is a horizontal cross-sectional view of the fitting portion of the second knock member and the clip member taken along line C-C in FIG. 11. FIG. 15 is a partially exploded perspective view of the barrel on the front barrel side. FIG. 16 is a partial vertical cross-sectional view of the barrel on the front barrel side. FIG. 17 is a partial perspective view of the front end portion of the front barrel in a non-writing state. FIG. 18 is another partial perspective view of the front end portion of the front barrel in a writing state. FIG. 19 is an exploded perspective view of the first and second eraser members. FIG. 20 is a vertical cross-sectional view of the first and second eraser members of FIG. 19. FIG. 21 is a perspective view of the first eraser member and another third eraser member. FIG. 22 is a vertical cross-sectional view of the first and third eraser members of FIG. 21. FIG. 23 is a partial perspective view showing the tips of multiple refills housed in a multi-core writing instrument. FIG. 24 is a side view of the front end portion of a multi-core writing instrument in a writing state. FIG. 25 is a side view of the front end portion of a multi-core writing instrument of a comparative example in a writing state. Fig. 26 is a perspective view of a multi-core writing instrument according to another embodiment of the present invention. Fig. 27 is a perspective view of the rear end of the multi-core writing instrument of Fig. 26.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Corresponding components throughout the drawings are designated by common reference numerals.

[0012] Figure 1 is an oblique view of a multi-core writing instrument 1, which is one form of writing instrument according to an embodiment of the present invention; Figure 2 is a front view of the multi-core writing instrument 1 of Figure 1, seen from the front in the axial direction; Figure 3 is a rear view of the multi-core writing instrument 1 of Figure 1, seen from the rear in the axial direction; Figure 4 is a cross-sectional view of the multi-core writing instrument 1 taken along line A-A in Figure 2; and Figure 5 is a cross-sectional view of the multi-core writing instrument 1 taken along line B-B in Figure 2.

[0013] The multi-core writing instrument 1 has a barrel 4 which has a front shaft 2 and a rear shaft 3 and is formed into a cylindrical shape overall, an inner tube 5 which is arranged inside the barrel 4 at the rear, four ballpoint pen refills 6 which have writing portions 6a and are writing bodies, i.e., refills, housed in the barrel 4, four first knock members 20 whose front ends are connected to the rear ends of the ballpoint pen refills 6, one mechanical pencil refill 7 which has writing portion 7a and is a refill housed in the barrel 4, and one second knock member 40 whose front end is connected to the rear end of the mechanical pencil refill 7.

[0014] In this specification, in the axial direction of the multi-core writing instrument 1, the side of the writing portions 6a and 7a is defined as the "front" side, and the side opposite the writing portions 6a and 7a is defined as the "rear" side. In describing each component, the "front" side and "rear" side, as well as the "outer" side and "inner" side, are defined in the same manner as the multi-core writing instrument 1, based on the state in which they are arranged in the multi-core writing instrument 1. Furthermore, "axis" or "central axis" refers to the central axis of the multi-core writing instrument 1, unless otherwise specified. The state in which either the writing portion 6a of the ballpoint pen refill 6 or the writing portion 7a of the mechanical pencil refill 7 protrudes from the front-end opening 9 of the barrel 4 is referred to as the writing state, and the state in which both the writing portions 6a of the ballpoint pen refill 6 and the writing portions 7a of the mechanical pencil refill 7 are retracted into the barrel 4 is referred to as the non-writing state.

[0015] The front axle 2 and rear axle 3 are connected via a cylindrical connecting member 8. That is, the connecting member 8 has a flange portion 8a, and the outer surface of the connecting member 8 forward of the flange portion 8a fits into the inner surface of the rear end portion of the front axle 2, while the outer surface of the connecting member 8 rearward of the flange portion 8a screws into the inner surface of the front end portion of the rear axle 3. A ring-shaped member 17 is fitted onto the outer surface of the flange portion 8a as decoration.

[0016] A front end opening 9 is formed at the front end of the barrel 4, specifically at the front end of the front axle 2. Five window holes 10 extending in the axial direction are formed in the side surface of the rear portion of the barrel 4, specifically at the side surface of the rear portion of the rear axle 3. An operating portion 21 of a first knock member 20 and an attachment portion 41 of a second knock member 40, both of which are disposed inside the barrel 4, protrude outward through the window holes 10. The first knock member 20 has an insertion member 30. A clip member 50 is provided on the second knock member 40.

[0017] The inner cylinder 5 is a member formed in a generally cylindrical shape. Five guide rails 11 are defined by five axially extending vertical holes formed in the side surface of the inner cylinder 5. Each of the first knock member 20 and the second knock member 40 is disposed within the inner cylinder 5 so as to be slidable in the front-rear direction along the corresponding guide rails 11 between the guide rails 11.

[0018] A cylindrical first erasing member 60 is inserted into and removably fitted to the inner surface of the rear end of the inner cylinder 5. A cover member 12 is removably fitted to the outer surface of the rear end of the inner cylinder 5, covering the first erasing member 60. A second erasing member 70 is removably fitted to the first erasing member 60 behind the cover member 12, penetrating the cover member 12.

[0019] Furthermore, the multi-core writing instrument 1 has five coil springs 13 through which the ballpoint pen refill 6 and the mechanical pencil refill 7 pass, a spacer 14, and a weight body 15 which is a cylindrical weight member.

[0020] The spacer 14 is a member formed into an overall cylindrical shape. The outer surface of the spacer 14 is fitted onto the inner surface of the rear barrel 3, thereby fixing the spacer 14 to the barrel tube 4. The spacer 14 is configured to separate the four ballpoint pen refills 6 and one mechanical pencil refill 7 without interfering with each other. That is, the spacer 14 has five through holes extending in the axial direction and spaced equally apart along the circumferential direction. The corresponding ballpoint pen refills 6 and mechanical pencil refills 7 are inserted through the five through holes. The front ends of the coil springs 13 that are passed through the ballpoint pen refills 6 and mechanical pencil refills 7 are supported by the spacer 14.

[0021] Fig. 6 is a perspective view of the first knock member 20, Fig. 7 is a side view of the first knock member 20, and Fig. 8 is a vertical cross-sectional view of the first knock member 20. In Figs. 7 and 8, the bottom and top are the front and rear sides, respectively, in the axial direction of the multi-core writing instrument 1, and the right and left are the inside and outside, respectively, in the radial direction of the multi-core writing instrument 1.

[0022] The first knock member 20 is a rod-shaped member. A protruding operating portion 21 is formed on the outer surface of the rear end of the first knock member 20. The operating portion 21 is formed in a gentle mountain shape along the longitudinal direction of the first knock member 20, and has an apex 21a as the portion that protrudes most radially outward. The operating portion 21 is the portion that is pressed particularly by the user's finger when the user performs a knock operation by pressing the first knock member 20 forward. At this time, the apex 21a and the portion behind the apex 21a are mainly pressed by the finger.

[0023] A pair of rail protrusions 22 extending in the axial direction are formed on the side surfaces of the first knock member 20 on both sides of the operating portion 21. A first insertion portion 23 is formed at the front end of the first knock member 20. The first insertion portion 23 is inserted into the rear end of the ballpoint pen refill 6 and engages with the ballpoint pen refill 6. A wide holding portion 24 for holding the coil spring 13 is formed behind the first insertion portion 23. A flange portion 25 for supporting the rear end of the coil spring 13 is formed behind the holding portion 24. A front cam 26 protruding inward is formed on the inner surface of the central portion of the first knock member 20, and a rear cam 27 protruding inward is formed on the inner surface of the rear end of the first knock member 20, i.e., behind the front cam 26. A locking protrusion 28 protruding rearward is formed at the rear end of the first knock member 20.

[0024] In the non-writing state, the first knock member 20 is disposed in the inner cylinder 5 so that the inner surface of the rail projection 22 and the inner surface of the retaining portion 24 are positioned on the guide rail 11. In this state, the rear end of the coil spring 13 that has passed through the ballpoint pen refill 6 is restrained from moving laterally by the retaining portion 24 and abuts against the front end surface of the flange portion 25. As described above, the front end of each of the coil springs 13 is supported by the spacer 14, and the first knock member 20 is constantly urged rearward by the coil spring 13.

[0025] To switch from the non-writing state to the writing state, the first knock member 20, to which the desired ballpoint pen refill 6 is connected, is pressed forward by a knocking operation, causing it to slide forward against the biasing force of the coil spring 13. When the rail protrusion 22 of the first knock member 20 slides beyond the rail length of the guide rail 11, the first knock member 20 disengages from the tip of the guide rail 11. At this time, the first knock member 20 moves radially inward into the barrel 4. Next, the biasing force of the coil spring 13 causes the locking protrusion 28 at the rear end of the first knock member 20 to lock onto the step 16 ( FIGS. 4 and 5 ) provided at the front end of the guide rail 11, thereby locking the first knock member 20 into the locked state. As a result, the writing portion 6 a of the desired ballpoint pen refill 6 protrudes from the front-end opening 9 of the barrel 4, and the multi-core writing instrument 1 enters the writing state.

[0026] On the other hand, to switch from the writing state to the non-writing state, another first knock member 20 or second knock member 40 other than the first knock member 20 corresponding to the ballpoint pen refill 6 in the writing state is slid forward against the biasing force of the coil spring 13. For example, when another first knock member 20 is slid along the guide rail 11, this other first knock member 20 collides with the locked first knock member 20 and pushes it outward in the radial direction, thereby releasing it from the guide rail 11. That is, the front cam 26 of the first knock member 20 sliding forward and the rear cam 27 of the locked first knock member 20 cooperate to apply a radially outward force to the locked first knock member 20. This releases the engagement between the locking protrusion 28 of the first knock member 20 and the step 16 of the guide rail 11. Next, due to the force of the coil spring 13, the ballpoint pen refill 6 connected to the first knock member 20, which was in a locked state, retracts, and the writing part 6a retracts into the barrel 4, and the multi-core writing instrument 1 enters a non-writing state.

[0027] The insert member 30 is a thin plate-shaped member. The insert member 30 is integrally provided with the first knock member 20 so as to extend perpendicular to the longitudinal direction of the first knock member 20, i.e., so as to penetrate the first knock member 20 in the radial direction. The outer surface of the insert member 30 is provided with a display unit 31 that is exposed from the outer surface of the first knock member 20, i.e., the outer surface of the operating unit 21. The display unit 31 is formed as a protrusion that protrudes slightly by a uniform height from the mountain-shaped surface of the operating unit 21. The display unit 31 may be formed flush with the surface of the operating unit 21 or may be formed as a recess. The insert member 30 and the display unit 31 are provided longitudinally further forward than the top portion 21a of the first knock member 20. Therefore, when the first knock member 20 is viewed from the front in the axial direction, the display unit 31 can be seen, whereas when the first knock member 20 is viewed from the rear in the axial direction, only the part of the operating unit 21 rearward of the top 21a is visible, and the display unit 31 cannot be seen.

[0028] The display unit 31 is formed in a rounded rectangular shape, but may be in other shapes such as a circle or a polygon. The display unit 31 is given a shape and color depending on the type and color of the ballpoint pen refill 6 connected to the first knock member 20. For example, if the ballpoint pen refill 6 contains red ink, the display unit 31 of the first knock member 20 connected to the ballpoint pen refill 6 may be colored red. Furthermore, if the ballpoint pen refill 6 is replaced with, for example, a marker pen refill, the display unit 31 of the first knock member 20 connected to the refill may be formed with a single spherical protrusion. The color and shape of the display unit 31 can be configured as desired.

[0029] In other words, when the first knock member 20 is disposed within the multi-core writing instrument 1, the display unit 31 is visible in FIG. 2 , which shows the multi-core writing instrument 1 viewed from the axial front, whereas the display unit 31 is not visible in FIG. 3 , which shows the multi-core writing instrument 1 viewed from the axial rear. Therefore, when performing a knock operation, which is mainly performed by pressing the rear portion of the first knock member 20 with a finger, the finger does not come into contact with the display unit 31, reducing the likelihood of skin oils and the like adhering to the display unit 31. Furthermore, when the multi-core writing instrument 1 is stored in an upright position with the writing part facing vertically downward, the likelihood of dust and the like adhering to the display unit 31 is reduced. Furthermore, because the display unit 31 is formed as a protrusion that protrudes slightly by a uniform height from the mountain-shaped surface of the operating part 21, it is less susceptible to the intrusion of dust and the like compared to a concave shape. Therefore, the multi-core writing instrument 1 can be provided with a stain-resistant display unit 31.

[0030] The operating unit 21 does not have to be mountain-shaped, and may be, for example, rectangular or cubic. In this case, a display unit may be provided on the front surface perpendicular to the axial direction. The insert member 30 does not have to penetrate the first knock member 20 in the radial direction. The insert member 30 may be placed in a non-penetrating hole provided on the outer surface of the first knock member 20. In other words, the insert member 30 may be configured in any shape as long as it can be placed on the first knock member 20 so that the display unit 31 is exposed on the outer surface of the first knock member 20.

[0031] The insert member 30 is formed integrally with the first knock member 20 by two-color molding. Specifically, the insert member 30 is formed by primary molding, and the first knock member 20 is formed by secondary molding. However, the insert member 30 may be a separate member inserted into a through hole or a non-through hole provided in the first knock member 20, and then integrally attached to the first knock member 20 by adhesive or fitting. The insert member 30 may be detachable from the first knock member 20. In this case, when changing the type or color of the ballpoint pen refill 6, the insert member 30 can be replaced with one having an indicator 31 that corresponds to the type, color, etc. of the ballpoint pen refill 6.

[0032] FIG. 9 is a vertical cross-sectional view showing the mold after primary molding in the two-color molding of the first knock member 20, and FIG. 10 is a vertical cross-sectional view showing the mold after secondary molding in the two-color molding of the first knock member 20.

[0033] In Figure 9, a movable mold 100 and a primary molding mold 200 are joined together. The movable mold 100 is provided with a plurality of ejector pins 110 for demolding the molded product, and the primary molding mold 200 is provided with a primary runner 210 for injecting the primary molding resin. In Figure 9, an insert member 30 is molded in the cavity formed by the movable mold 100 and the primary molding mold 200 with the primary molding resin injected through the primary runner 210. A seal portion P1, which also serves as a dividing surface surrounding the insert member 30, is formed inside the seal portion P1. A seal surface 32 of the insert member 30 is formed inside the seal portion P1, and is defined by the dividing surface including the seal portion P1 on the movable mold 100 side. The seal portion P1 prevents the primary molding resin from leaking out of the cavity.

[0034] From the state shown in FIG. 9 , the movable mold 100, together with the insert member 30, is separated from the primary molding mold 200 and joined to the secondary molding mold 300. A secondary runner 310 for injecting secondary molding resin is provided on the secondary molding mold 300 side. In FIG. 10 , the insert member 30 formed by the primary molding is placed in the cavity formed by the movable mold 100 and the secondary molding mold 300. The first knock member 20 is molded integrally with the insert member 30 by the secondary molding resin injected through the secondary runner 310. The sealing surface 32 of the insert member 30 is pressed against the parting plane P2 between the movable mold 100 and the secondary molding mold 300. Therefore, the sealing surface 32 prevents the secondary molding resin from leaking toward the insert member 30, thereby preventing the shape of the insert member 30 from being deformed by the secondary molding resin. Finally, the first knock member 20 is released from the mold by the ejector pin 110, completing the two-color molding process.

[0035] Figure 11 is a side view of the second knock member 40 equipped with a clip member 50, Figure 12 is an exploded perspective view of the second knock member 40, and Figure 13 is another exploded perspective view of the second knock member 40. In Figures 11 and 12, the left and right sides respectively correspond to the front and rear sides in the axial direction of the multi-core writing instrument 1, and the bottom and top correspond to the inside and outside in the radial direction of the multi-core writing instrument 1. Figure 14 is a cross-sectional view of the fitting portion of the second knock member 40 and the clip member 50 taken along line C-C in Figure 11. In Figure 14, the left and right sides respectively correspond to the front and rear sides in the axial direction of the multi-core writing instrument 1.

[0036] The second knock member 40 is a rod-shaped member. A protruding attachment portion 41 is formed on the outer surface of the rear end of the second knock member 40. The attachment portion 41 has a base portion 41a provided on the outer surface of the rear end of the second knock member 40, a rectangular parallelepiped fitting head portion 41b provided outside the base portion 41a, and a constricted locking neck portion 49 connecting the base portion 41a and the fitting head portion 41b. A rectangular flat, concave-convex fitting surface 41c is provided at the rear end of the fitting head portion 41b.

[0037] A pair of rail protrusions 42 extending in the axial direction are formed on the side surfaces of the second knock member 40 on both sides of the mounting portion 41. A second insertion portion 43 is formed at the front end of the second knock member 40. The second insertion portion 43 is inserted into the rear end of the mechanical pencil refill 7 and engages with the mechanical pencil refill 7. A wide retaining portion 44 for retaining the coil spring 13 is formed behind the second insertion portion 43. A flange portion 45 for supporting the rear end of the coil spring 13 is formed behind the retaining portion 44. A front cam 46 protruding inward is formed on the inner surface of the central portion of the second knock member 40. A rear cam 47 protruding inward is formed on the inner surface of the rear end of the second knock member 40, i.e., behind the front cam 46. A rear locking protrusion 48 protruding rearward is formed at the rear end of the front cam 46.

[0038] In the non-writing state, the second knock member 40 is disposed within the inner cylinder 5 so that the inner surface of the rail protrusion 42 and the inner surface of the retaining portion 44 are positioned on the guide rail 11. In this state, the rear end of the coil spring 13 that has passed through the mechanical pencil refill 7 is restrained from moving laterally by the retaining portion 44 and abuts against the front end surface of the flange portion 45. As described above, the front end of each of the coil springs 13 is supported by the spacer 14, and therefore the front cam 46 is constantly biased rearward by the coil spring 13.

[0039] The switching from the non-writing state to the writing state and the switching from the writing state to the non-writing state are similar to those in the case of the first knock member 20 described above, and therefore a description thereof will be omitted.

[0040] The writing lead of the mechanical pencil refill 7 can be advanced by knocking the rear end of the multi-core writing instrument 1. That is, the inner tube 5 is not fixed to the rear barrel 3 or other components, and the inner tube 5 can be advanced by pressing the rear end of the multi-core writing instrument 1, for example, the cover member 12, forward. As described above, the inner tube 5 is urged rearward by the five coil springs 13, the front ends of which are supported by the spacer 14, via the first knock member 20 and the second knock member 40. Therefore, when the mechanical pencil refill 7 is in a writing state, if the inner tube 5 is advanced against the urging force of the coil springs 13 by knocking, the mechanical pencil refill 7 will engage near the front end opening 9 of the front barrel 2, while the writing lead will advance inside the mechanical pencil refill 7, and the writing lead will be advanced.

[0041] In a typical multi-lead writing instrument, the writing lead is advanced by knocking the knock member of the mechanical pencil refill. However, in the multi-lead writing instrument 1 according to this embodiment, the writing lead is advanced by knocking the rear end of the multi-lead writing instrument 1, rather than by knocking the second knock member 40 to which the mechanical pencil refill 7 is connected. Therefore, the user can use the multi-lead writing instrument 1 as a mechanical pencil with the same feel as a typical mechanical pencil that is not a multi-lead writing instrument.

[0042] The clip member 50 is fitted to the second knock member 40 via the fitting head 41b and the locking neck 49. The clip member 50 is formed by processing a metal plate-shaped member. The front end of the clip member 50 is formed with two opposing clamping walls 51 that extend inward. The two clamping walls 51 are configured to clamp an article between themselves and clamping protrusions 3a ( FIG. 4 ) formed on opposing surfaces of the rear axle 3. The rear end of the clip member 50 is formed with two opposing side walls 52 that extend inward, and locking teeth 53 formed by bending the ends of the side walls 52 toward each other. A rectangular opening 54 is formed in the sloped rear end of the clip member 50. The rectangular opening 54 allows the second knock member 40 to be seen outside the clip member 50, thereby demonstrating the clip member 50's function as a knock member rather than merely a decorative clip. Furthermore, since the shape is different from that of the first knock member 20, it is easy to store a writing refill containing a solid lead such as a mechanical pencil or a ballpoint pen refill with a functional color different from that of the display unit 31.

[0043] 14 , the cross-sectional shape of the locking neck 49 of the second knock member 40 and the contour defined internally by the cross section of the locking teeth 53 of the clip member 50 are substantially complementary. The locking neck 49 has a pair of small protrusions 49a formed to protrude laterally and a pair of large protrusions 49b formed to protrude further laterally in front of the pair of small protrusions 49a. The small protrusions 49a are formed with a pair of first inclined surfaces 49a1 facing diagonally rearward, and the large protrusions 49b are formed with a pair of second inclined surfaces 49b1 inclined at approximately the same angle as the first inclined surfaces 49a1. The small protrusions 49a are formed with first locking surfaces 49a2 perpendicular to the axial direction, and the large protrusions 49b are formed with second locking surfaces 49b2 similar to the first locking surfaces 49a2. The front ends of the locking teeth 53 of the clip member 50 are provided with guide portions 53a that approach each other as they extend rearward.

[0044] The clip member 50 is attached to the second knock member 40 by sliding the clip member 50 from the rear to the front of the second knock member 40 relative to the attachment portion 41. At the rear end of the clip member 50, a space capable of containing the mating head 41b of the second knock member 40 is defined by the two side walls 52 and the locking teeth 53. The length of the locking neck 49 of the second knock member 40, i.e., the distance between the base 41a and the mating head 41b, is slightly greater than the thickness of the locking teeth 53 of the clip member 50. When the clip member 50 is slid from the rear to the front of the second knock member 40 relative to the attachment portion 41, the mating head 41b of the second knock member 40 is accommodated in the space between the two side walls 52 and the locking teeth 53. The locking neck 49 of the second knock member 40 is inserted between the locking teeth 53 of the clip member 50 and engages with the locking teeth 53.

[0045] When the locking neck portion 49 of the second knock member 40 is inserted between the locking teeth 53 of the clip member 50, the rear end of the locking neck portion 49 is guided between the locking teeth 53 by the guide portion 53a provided at the front end between the locking teeth 53. Next, the first inclined surface 49a1 of the small protrusion 49a and the second inclined surface 49b1 of the subsequent large protrusion 49b elastically deform to widen the gap between the locking teeth 53, allowing the locking neck portion 49 of the second knock member 40 to be inserted further rearward. As a result, as shown in FIG. 14 , the locking neck portion 49 of the second knock member 40 is positioned between the locking teeth 53 of the clip member 50, completing the attachment of the second knock member 40 to the clip member 50. On the other hand, when an attempt is made to remove the clip member 50, the first locking surface 49a2 of the small protrusion 49a and the second locking surface 49b2 of the large protrusion 49b lock onto the locking tooth portion 53, thereby preventing the clip member 50 from coming off unintentionally.

[0046] When the second knock member 40 and the clip member 50 are attached as shown in FIG. 11 , the locking uneven surface 41c of the second knock member 40 protrudes slightly from the rectangular opening 54 of the clip member 50 and is exposed. The locking uneven surface 41c has fine irregularities. Because the locking uneven surface 41c protrudes from the clip member 50, it is configured to catch the pad of a finger when the second knock member 40 is knocked. The fine irregularities of the locking uneven surface 41c provide an additional anti-slip effect. The locking uneven surface 41c may have a matte finish. The matte finish is achieved by forming multiple grooves on the surface of the locking uneven surface 41c. The groove width of each groove is preferably in the range of 0.1 to 0.3 mm, and the pitch of each groove is preferably 0.2 to 0.8 mm.

[0047] When the second knock member 40 is disposed in the multi-core writing instrument 1, the central axis of the multi-core writing instrument 1 and the longitudinal direction of the second knock member 40 are substantially parallel to each other. The locking uneven surface 41c is inclined forward and outward with respect to the central axis of the multi-core writing instrument 1. Specifically, as shown in Figure 11, for convenience, if a parallel line L parallel to the central axis is considered, and the angle between the parallel line L and the locking uneven surface 41c is defined as angle θ, it is preferable that angle θ be an acute angle.

[0048] More specifically, during the knocking operation, the second knock member 40 advances along the guide rail 11 of the inner tube 5, and then enters the barrel 4 toward the central axis, whereby the locking protrusion 48 locks with the step 16. By tilting the locking uneven surface 41c that the user's fingers directly contact, the pressing force during the knocking operation acts in the direction in which the second knock member 40 enters the barrel 4, making it possible to easily and reliably lock the locking protrusion 48 with the step 16. If the angle θ is less than 15 degrees, there is little improvement in the operability of the knocking operation, and if it exceeds 60 degrees, it becomes difficult to press forward during the knocking operation, so it is preferable to tilt the angle between 15 and 60 degrees, and preferably between 30 and 45 degrees.

[0049] The second knock member 40 and the clip member 50 may be configured in any manner as long as they are interlockable. In this case, the rear end of the mating portion where the clip member 50 is mated, specifically the locking uneven surface 41c, may be configured in any manner as long as the locking uneven surface 41c protrudes rearward through the clip member 50. For example, the locking uneven surface 41c and the corresponding rectangular opening 54 of the clip member 50 are rectangular, but may also be circular or other polygonal. Furthermore, the locking uneven surface 41c may be roughened rather than matte-patterned, as long as it provides an anti-slip effect. For example, a surface having a higher surface roughness Ra than the surface of the rail projection 42 can be considered rough.

[0050] Figure 15 is a partially exploded perspective view of the barrel 4 on the front barrel 2 side, Figure 16 is a partial vertical cross-sectional view of the barrel 4 on the front barrel 2 side, Figure 17 is a partial perspective view of the front end portion of the front barrel 2 in a non-writing state, and Figure 18 is another partial perspective view of the front end portion of the front barrel 2 in a writing state.

[0051] The front barrel 2 is a resin molded product formed by injection molding. A leather-patterned embossing may be applied to all or part of the outer surface of the front barrel 2, resulting in a so-called leather-grained pattern. Examples of the leather-grained pattern include the patterns described in JP 2007-160637 A. The unevenness of the leather-grained pattern may have a depth of, for example, 60 to 100 μm. By applying a leather-grained pattern to the front barrel 2, the surface is less susceptible to scratches, and if scratches do occur, the scratches are less noticeable. Furthermore, by applying a leather-grained pattern to the front barrel 2, the gloss value can be reduced, thereby imparting a luxurious design to the multi-lead writing instrument 1 as a whole. The leather-grained pattern may be applied to the rear barrel 3, or to all or part of the barrel tube 4.

[0052] Two opposing longitudinal protrusions 2a extending in the axial direction are formed on the inner surface of the front axle 2. Three mating protrusions 2b are also formed integrally and at equal intervals along the circumferential direction on the inner surface of the front axle 2. An annular locking step 2c is formed on the inner surface of the front axle 2 forward of the two longitudinal protrusions 2a and the three mating protrusions 2b. Three retaining protrusions 18 are also formed integrally and at equal intervals along the circumferential direction on the front end opening 9 of the front axle 2.

[0053] The front end of the cylindrical weight 15 is formed with a tapered portion 15a. The outer surface of the weight 15 is provided with longitudinal grooves 15b that correspond to the two longitudinal protrusions 2a of the front body 2. When the weight 15 is inserted through the rear-end opening of the front body 2, the weight 15 is inserted so that the longitudinal grooves 15b of the weight 15 accommodate the longitudinal protrusions 2a of the front body 2. This prevents the weight 15 from rotating around its central axis. The weight 15 moves along the inner surface of the front body 2, which is tapered so that the tapered portions 15a correspond to the tapered portions, and the front edge of the weight 15 engages with the locking shoulders 2c of the front body 2. Furthermore, the outer surface of the weight 15 engages with the three fitting protrusions 2b of the front body 2, completing the attachment of the weight 15 to the front body 2.

[0054] Connecting member 8 has the flange portion 8a described above and two cutout portions 8b extending rearward from the front-end opening. When connecting member 8 is inserted through the rear-end opening of front body 2 to which weight 15 is attached, connecting member 8 is inserted so that cutout portions 8b of connecting member 8 accommodate the rear ends of vertical protrusions 2a of front body 2. When fitting of connecting member 8 to front body 2 is complete, the front end face of connecting member 8 and the rear end face of weight 15 face each other, restricting retraction of weight 15.

[0055] The weight 15 attached as described above is restricted in rotation and movement in the forward and backward directions and radial directions, so that the weight 15 moves within the barrel 4 during writing operations, etc., and the generation of noise and vibrations that are unpleasant to the user is prevented.

[0056] An annular member 17 is fitted onto the outer surface of the flange portion 8a of the connecting member 8 fitted onto the front barrel 2. The annular member 17 has an outer surface that is flush with the outer surfaces of the front barrel 2 and the rear barrel 3. The outer surface of the annular member 17 is given a color or pattern, etc., which enhances the design of the multi-core writing instrument 1.

[0057] The weight 15 is formed from a material with a relatively higher specific gravity than the other components, such as a metal material. Considering disposal, it is preferable that the weight 15 be formed primarily from the material of the front barrel 2 or barrel tube 4, containing metal powder. In this case, the weight 15 is preferably positioned within the barrel tube 4 between 20 mm from the tip of the refill and half the length of the multi-core writing instrument 1 when the refill protrudes from the front-end opening 9. Furthermore, it is preferable that the center of gravity of the multi-core writing instrument 1 is located between 20 mm from the tip of the refill and half the length of the multi-core writing instrument 1 when the refill is in the writing state, and that the weight between 20 mm from the tip of the refill and half the length of the multi-core writing instrument 1 accounts for 50% or more of the total weight of the multi-core writing instrument 1. By adjusting the weight distribution and center of gravity using the weight 15, the balance of the multi-core writing instrument 1 can be properly maintained during writing. As a result, the user can write stably and comfortably.

[0058] 17 , each of the three retaining projections 18 is provided on the peripheral edge of front end opening 9 of front body 2. That is, the peripheral edge of front end opening 9 of front body 2 is provided with an annular front end surface 2d facing forward, and a cylindrical surface 2e within front end opening 9 adjacent to front end surface 2d. Retaining projection 18 is formed by a cylindrical inward projection 18a that projects radially inward from cylindrical surface 2e of front body 2, and a front projection 18b that projects forward from front end surface 2d of front body 2.

[0059] Referring to Figure 18, each of the three inner protrusions 18a of the retaining protrusion 18 is configured to abut against the ballpoint pen refill 6 when in a writing state. That is, the diameter of the inscribed circle of the three retaining protrusions 18, centered on the central axis of the barrel 4, specifically the diameter of the inscribed circle of the inner protrusion 18a, is configured to be equal to or slightly smaller than the outer diameter of the ballpoint pen refill 6 that abuts against the retaining protrusion 18, i.e., a tight fit. The inner surface of the cylindrical inner protrusion 18a of the retaining protrusion 18 is formed complementarily to the outer surface of the ballpoint pen refill 6 that abuts against the retaining protrusion 18. Therefore, the radial movement of the ballpoint pen refill 6 is restricted by the three retaining protrusions 18, preventing rattling of the ballpoint pen refill 6 when writing. As a result, the user can write stably and comfortably.

[0060] The axial length of each of the holding protrusions 18 is preferably 0.5 to 2.0 mm. Furthermore, when the holding protrusions 18 are fitted together by an interference fit, the interference range is preferably 0 to 1.0% of the outer diameter of the ballpoint pen refill 6 that abuts against the holding protrusions 18, that is, the diameter of the inscribed circle of the holding protrusions 18 is preferably 99 to 101% of the outer diameter of the abutting ballpoint pen refill 6. Specifically, the interference range is preferably -0.001 to -0.050 mm.

[0061] The front protrusion 18b of the holding protrusion 18 protrudes forward beyond the front end opening 9 of the front barrel 2, thereby providing an appropriate degree of elasticity to prevent the ballpoint pen refill 6 from rattling during writing. That is, the front protrusion 18b has a cantilever shape and can bend radially inward or outward. Therefore, rattling of the ballpoint pen refill 6 is prevented by the inner protrusion 18a, and the radially inward or radially outward elasticity of the front protrusion 18b provides a soft writing feel.

[0062] 18, the case where the ballpoint pen refill 6 is in the writing state is described, but the same applies to the case where the mechanical pencil refill 7 is in the writing state. At least one holding protrusion 18 may be provided, and two or four or more may be provided, and therefore six may be provided, which is double the number of holding protrusions 18 in this embodiment. When multiple holding protrusions 18 are provided, they are preferably provided at equal intervals along the circumferential direction.

[0063] FIG. 19 is an exploded perspective view of the first erasing member 60 and the second erasing member 70, and FIG. 20 is a vertical cross-sectional view of the first erasing member 60 and the second erasing member 70 of FIG.

[0064] As described above, the cylindrical first erasing member 60 is inserted into and removably fitted to the inner surface of the rear end of the inner cylinder 5. The cover member 12 is removably fitted to the outer surface of the rear end of the inner cylinder 5, covering the first erasing member 60. Behind the cover member 12, the second erasing member 70 penetrates the cover member 12 and removably fits to the first erasing member 60. Each of the first erasing member 60 and the second erasing member 70 is configured to be able to erase at least one type of handwriting from multiple refills of the multi-core writing instrument 1.

[0065] The cover member 12 is a cylindrical member having an open end and a closed end. A circular hole 12a is formed in the closed rear end. A plurality of fitting protrusions 12b are provided on the inner surface of the cover member 12. The fitting protrusions 12b are provided on the outer surface of the rear end of the inner tube 5 and ride over a plurality of annular protrusions spaced apart in the axial direction, allowing the cover member 12 to detachably fit onto the rear end of the inner tube 5.

[0066] The first erasing member 60 is a thick, cylindrical member. An insertion hole 61 is formed through the first erasing member 60 in the axial direction. The second erasing member 70 is a hook- or nail-shaped member. The second erasing member 70 has a cylindrical columnar portion 71, a conical portion 72 provided at the tip of the columnar portion 71, and a pair of ears 73 provided at the rear end of the columnar portion 71. The outer diameter of the columnar portion 71 is the same as or slightly larger than the inner diameter of the insertion hole 61 of the first erasing member 60. The inner diameter of the circular hole 12a of the cover member 12 is approximately the same as the inner diameter of the insertion hole 61 of the first erasing member 60. The ears 73 are formed by cutting a disk-shaped member along a line corresponding to the chord of a sector with a central angle of approximately 90 degrees, and then cutting the remaining portion toward the center of the circle to divide it into equal parts. This is arranged so as to straddle the end of the columnar portion 71, thereby forming a pair of ears.

[0067] The columnar portion 71 of the second erasing member 70 penetrates both the circular hole 12a of the cover member 12 and the insertion hole 61 of the first erasing member 60, thereby detachably fitting with the first erasing member 60. Therefore, the cover member 12 may be omitted. The ear-shaped portion 73 is formed wide, so it can be used as a gripping portion to hold when pulling the second erasing member 70 out of the first erasing member 60.

[0068] The first erasing member 60 is an erasing member that erases handwriting made with the ballpoint pen refill 6, and the second erasing member 70 is an erasing member that erases handwriting made with the mechanical pencil refill 7, i.e., an eraser. However, the first erasing member 60 may be an erasing member that erases handwriting made with the mechanical pencil refill 7, and the second erasing member 70 may be an erasing member that erases handwriting made with the ballpoint pen refill 6. Furthermore, all or a part of the cover member 12 may be an erasing member that erases handwriting made with the ballpoint pen refill 6 or an erasing portion that erases handwriting made with the mechanical pencil refill 7.

[0069] The ballpoint pen refill 6 may be a ballpoint pen refill or other types of refills, such as a marking pen, a touch pen, or an eraser. The ballpoint pen refill 6 may also be a ballpoint pen containing thermochromic ink. Here, thermochromic ink refers to ink that maintains a predetermined color (first color) at room temperature (e.g., 25°C), changes to a different color (second color) when heated to a predetermined temperature (e.g., 60°C), and then returns to its original color (first color) when cooled to a predetermined temperature (e.g., -5°C). In a thermochromic writing instrument using thermochromic ink, the second color is rendered colorless, and "erasing" refers to heating a line drawn in the first color (e.g., red) to make it colorless. Therefore, any of the eraser members or eraser portions described above acts as a friction member, rubbing against a writing surface on which the line has been drawn to generate frictional heat, thereby rendering the drawn line colorless, i.e., erasing it. Naturally, the second color may be a color other than colorless.

[0070] The multi-core writing instrument 1 may include any number and type of three types of refills: a thermochromic refill capable of writing thermochromic handwriting, a non-thermochromic refill capable of writing other than thermochromic handwriting, and a mechanical pencil refill. The non-thermochromic refill may be a ballpoint pen refill containing ink other than thermochromic ink, i.e., a non-thermochromic ink, or may be the above-mentioned marking pen. The multi-core writing instrument may have a total of three refills, including two thermochromic refills and one non-thermochromic refill, without a mechanical pencil refill. In this case, one of the first erasing member 60 and the second erasing member 70 is a friction member capable of erasing handwriting made with a thermochromic refill, and the other of the first erasing member 60 and the second erasing member 70 is an erasing member capable of erasing handwriting made with a non-thermochromic refill.

[0071] In short, the first erasing member 60 is an erasing member that erases handwriting from at least one of the multiple refills of the multi-core writing instrument 1, and the second erasing member 70 is configured to erase handwriting from at least one of the other multiple refills of the second erasing member 70. Furthermore, a part or all of the cover member 12 may be an erasing section that erases handwriting from any of the refills of the multi-core writing instrument 1.

[0072] The thermochromic ink uses a thermochromic microcapsule pigment with a low-temperature discoloration temperature of -30°C or higher in combination with a thermochromic microcapsule pigment with a low-temperature discoloration temperature of less than -30°C, and is measured by measuring the absolute value of the difference in brightness in the Munsell color system of the ink across the boundary of -30°C, and the chroma (C ＊ ab), the value of a ＊ value and b ＊ Using the values, the formula (a ２ +b ２ ) １／２ It is preferable that the ink for a ballpoint pen is one in which at least one of the absolute values ​​of the difference in saturation between the inks is 1 or more.

[0073] The non-thermochromic ink contains at least a colorant (A) containing a pigment, olefin-based resin particles (B), and water, wherein the olefin-based resin particles (B) have a needle penetration hardness of 1 or more and an average particle size of 15 μm or less as measured by a Cole counter method, the mass ratio [(A) / (B)] of the solid content of the colorant (A) to the olefin-based resin particles (B) is in the range of 1 to 100, the content of the olefin-based resin particles (B) is 0.01 to 20 mass% with respect to the total amount of the ink composition, and the dissolved oxygen concentration in the aqueous ink composition for a ballpoint pen is 5% or less. ２ It is preferable that the water-based ink for ballpoint pen is as described above.

[0074] The friction member for thermochromic ink is preferably a crosslinked styrene-based elastomer having a compression set of 80% or less at 120°C and a durometer A hardness of 60 to 98. The 120°C compression set is 80% or less, more preferably less than 60%, from the viewpoint of good abrasion resistance of the friction member under high temperature conditions. The compression set is a value measured in accordance with JIS K6262. The durometer A hardness is a value measured in accordance with JIS K6253-3 from the viewpoint of good discoloration of handwriting with thermochromic ink and good abrasion resistance of the friction member. Furthermore, the Taber abrasion amount CS-17 measured in the Taber abrasion test specified in JIS K7204 is preferably less than 10 mg as the abrasion resistance of the friction member. Furthermore, when used as an eraser, the Taber abrasion resistance measured by the Taber abrasion test specified in JIS K7204 must be 10 mg or more using CS-17. It is preferable to use at least non-phthalate plasticizers, such as alkylsulfonic acid phenyl esters, cyclohexanedicarboxylic acid esters, methacrylic acid esters, acrylic acid esters, acetyl tributyl citrate, adipic acid polyesters, acetyl tributyl citrate, sebacate diesters, and diethylene glycol dibenzoate, which are capable of suppressing environmental hormones (endocrine disruptors). Furthermore, friction members for thermochromic inks may be made of materials with thermal conductivity of less than 0.05 W / (m·K). Examples of materials with thermal conductivity less than 0.05 W / (m·K) include cloth and fiber (thermal conductivity 0.04 W / (m·K)). Thermal conductivity was measured using an AUTOΛ (HC-074) manufactured by Eiko Seiki, with a pressure of 250 kg / m. ２ The thermal conductivity is determined at a high temperature plate temperature of 35° C. and a low temperature plate temperature of 5° C. When the thermal conductivity is less than 0.05 W / (m·K), a soft touch can be obtained when the color is erased.

[0075] The first erasing member 60, the second erasing member 70, and the cover member 12 may be attached to the multi-core writing instrument 1 to erase handwriting, or may be removed from the multi-core writing instrument 1 and used individually to erase handwriting. The first erasing member 60, the second erasing member 70, and the cover member 12 can erase handwriting over a variety of areas depending on their respective shapes and locations. In particular, the second erasing member 70 can erase handwriting in dots or lines using the tip of the conical portion 72, and can also erase handwriting in areas using the side of the conical portion 72. Furthermore, the ear-shaped portion 73 can erase handwriting over a variety of areas using the rear end, side, and periphery.

[0076] 21 is a perspective view of the first erasing member 60 and the third erasing member 80, and FIG. 22 is a vertical cross-sectional view of the first erasing member 60 and the third erasing member 80 of FIG.

[0077] 21 and 22 are identical to the cover member 12 and first erasing member 60 shown in Figures 19 and 20 except that a female thread portion 12c is provided instead of the multiple fitting protrusions 12b on the inner surface of the cover member 12. Therefore, the rear end of the corresponding inner tube 5 is provided with a male thread portion that can be threaded with the female thread portion 12c of the cover member 12.

[0078] The third erasing member 80 is a hook- or nail-shaped member. The third erasing member 80 has a cylindrical columnar portion 81, a conical portion 82 provided at the tip of the columnar portion 81, and a triangular portion 83 provided at the rear end of the columnar portion 81. The outer diameter of the columnar portion 81 is the same as or slightly larger than the inner diameter of the insertion hole 61 of the first erasing member 60. The triangular portion 83 is formed as if a triangular plate member were attached to the end of the columnar portion 81. A large rounded portion 84 is formed at the first vertex of the triangular portion 83, which corresponds to the rear end of the third erasing member 80. A small rounded portion 85 is formed at the second vertex of the triangular portion 83, which is an arc-shaped portion with a smaller radius than the large rounded portion 84. An acute-angled portion 86 is formed at the third vertex of the triangular portion 83. On both sides of the triangular portion 83, three parallel linear protrusions 87 are formed, which are perpendicular to the axial direction and spaced apart from each other in the axial direction.

[0079] The columnar portion 81 of the third erasing member 80 penetrates both the circular hole 12a of the cover member 12 and the insertion hole 61 of the first erasing member 60, thereby detachably fitting with the first erasing member 60. Therefore, the cover member 12 may be omitted. The triangular portion 83 is formed wide, so it can be used as a gripping portion to grip when pulling the third erasing member 80 out of the first erasing member 60. At this time, the linear protrusions 87 formed on the triangular portion 83 have a non-slip effect when pulling the third erasing member 80 out of the first erasing member 60.

[0080] Similar to the second erasing member 70, the third erasing member 80 can erase handwriting in a dotted or linear form using the tip of the conical portion 82, and can also erase handwriting in a planar form using the side of the conical portion 82. Furthermore, the triangular portion 83 can erase handwriting in various ranges by using each of its vertices, which have different shapes, i.e., the large round portion 84, the small round portion 85, and the acute angle portion 86.

[0081] The third eraser member 80 can be attached to the multi-core writing instrument 1 in place of the second eraser member 70. In other words, the second eraser member 70 and the third eraser member 80 can be attached to the multi-core writing instrument 1 in an interchangeable manner. For example, the ear-shaped portion 73 of the second eraser member 70 and the triangular portion 83 of the third eraser member 80 may be formed into the face of an animal or character, allowing for interchangeable faces of preference. Alternatively, the materials of the second eraser member 70 and the third eraser member 80 may be changed so that they can erase handwriting from different types of refills, and the second eraser member 70 and the third eraser member 80 may be selected depending on the refill housed in the multi-core writing instrument 1.

[0082] 23 is a partial perspective view showing the tips of a plurality of refills housed in a multi-core writing instrument 1. The multi-core writing instrument 1 has a mechanical pencil refill 7, and ballpoint pen refills 6 include ballpoint pen refills 6A, 6B, 6C, and 6D.

[0083] 23, the writing portion 6aA of the ballpoint pen refill 6A and the writing portion 6aB of the ballpoint pen refill 6B have the same outer shape, and the writing portion 6aC of the ballpoint pen refill 6C and the writing portion 6aD of the ballpoint pen refill 6D have the same outer shape. The outer shapes of the writing portion 6aA of the ballpoint pen refill 6A and the writing portion 6aB of the ballpoint pen refill 6B are different from the outer shapes of the writing portion 6aC of the ballpoint pen refill 6C and the writing portion 6aD of the ballpoint pen refill 6D. Specifically, the writing portion 6aA of the ballpoint pen refill 6A and the writing portion 6aB of the ballpoint pen refill 6B have conical surfaces 6A1 and 6B1, respectively, each of which is formed by a single cone. The writing portion 6aC of the ballpoint pen refill 6C and the writing portion 6aD of the ballpoint pen refill 6D each have a conical surface 6C1 and a conical surface 6D1 formed by a series of cones with two different apex angles. The conical surface 6A1 of the writing portion 6aA of the ballpoint pen refill 6A and the conical surface 6B1 of the writing portion 6aB of the ballpoint pen refill 6B, which have the same outer shape, are treated with different glosses, colors, patterns, and other distinguishable treatments. The conical surface 6C1 of the writing portion 6aC of the ballpoint pen refill 6C and the conical surface 6D1 of the writing portion 6aD of the ballpoint pen refill 6D, which have the same outer shape, are similarly treated with different glosses, colors, patterns, and other distinguishable treatments.

[0084] As described above, the multiple ballpoint pen refills 6 can be variously combined, including thermochromic and non-thermochromic refills, and their respective colors. The type and color of the refill housed in the multi-core writing instrument 1 can be identified by the display portion 31 of the first knock member 20. Here, as shown in FIG. 18 , the writing portion 6a of the ballpoint pen refill 6 protrudes from the front end opening 9 of the front barrel 2, making it easily visible to the user. Therefore, by setting the shape, color, pattern, gloss, etc. of the writing portion 6a according to the type and color of the refill, the user can easily identify the type and color of the ballpoint pen refill 6 in writing mode. Furthermore, if a mechanical pencil refill 7 protrudes from the front end opening 9, its shape makes it easy to identify that it is a mechanical pencil refill 7.

[0085] In the above-described embodiment, the writing part has a conical surface formed by connecting cones with two different apex angles. However, the writing part may have a conical surface formed by connecting cones with three or more different apex angles. Furthermore, the apex angle of the conical surface formed by a single cone and the apex angle of each of the conical surfaces formed by connecting two or more different cones may be set arbitrarily. The type and color of the refill may be identified by the difference in apex angle. In other words, each of the multiple refills has a writing part, and the shape and color of the writing part may be formed to differ from one another depending on the type or color of writing with the multiple refills. This allows the type and color of the refill to be identified by visually checking the writing part.

[0086] When in a writing state, it is preferable that the writing portion 6a can be easily seen. By visually checking the writing portion 6a and confirming its position, the ease of writing can be improved. In particular, when a user holds the multi-core writing instrument 1 and writes, it is preferable that the writing portion 6a can be easily seen, not only to identify the type and color of the ballpoint pen refill 6 as described above, but also to determine whether the writing portion 6a protrudes from the front end opening 9 of the front barrel 2. An optimal or preferred configuration for this purpose will be described with reference to Figures 24 and 25.

[0087] Fig. 24 is a side view of the front end of the multi-core writing instrument 1 in a writing state, and Fig. 25 is a side view of the front end of the multi-core writing instrument 200 of the comparative example in a writing state. As shown in Fig. 24, the writing part 6a has a ball 6a1 provided at the tip of the writing part 6a and a ball holder 6a2 that rotatably holds the ball 6a1.

[0088] In a side view or longitudinal cross-sectional view of the multi-core writing instrument 1 as shown in Figure 24, in which the multi-core writing instrument 1 is viewed from the side, consider an imaginary tangent line T at the front edge E of the outer circumferential surface near the front end face 2d of the front barrel 2. In this case, the front barrel 2 or the writing part 6a is arranged so that the imaginary tangent line T extending forward passes through the writing part 6a. When the imaginary tangent line T passes through the writing part 6a, the writing part 6a can be easily seen. In other words, if the multi-core writing instrument 1 is viewed from the rear to the front along the imaginary tangent line T, the fact that the imaginary tangent line T passes through the writing part 6a means that the writing part 6a can be seen.

[0089] 25, the imaginary tangent line T at the front edge E of the outer peripheral surface near the front end face 202d of the front barrel 202 does not pass through the writing part 206a. In other words, the imaginary tangent line T passes outside the writing part 206a relative to the central axis, making it difficult or impossible for the user to see the writing part 206a.

[0090] Therefore, it is preferable that the imaginary tangent line T passes through the writing portion 6a. More specifically, it is preferable that the imaginary tangent line T passes through the writing portion 6a even if it is outside the ball 6a1 with respect to the central axis. This allows the user to at least see the writing portion 6a. It is more preferable that the imaginary tangent line T passes through the ball 6a1 and the ball holder 6a2. This allows the user to see the ball 6a1. Furthermore, it is preferable that the imaginary tangent line T passes through the writing portion 6a inside the ball 6a1 with respect to the central axis. This allows the user to reliably see the ball 6a1.

[0091] The relationship between the imaginary tangent line T and the writing portion described above can be applied to writing portions of other writing instruments, such as fountain pens, in addition to writing portions of ballpoint pen refills.

[0092] However, writing implements are sometimes used together with other items. In such cases, when alternately holding the writing implement and the other items, the placement or arrangement of these items must be taken into consideration. This will be explained with reference to Figures 26 and 27.

[0093] Figure 26 is a perspective view of a multi-core writing instrument 100 according to another embodiment of the present invention, and Figure 27 is a perspective view of the rear end of the multi-core writing instrument 100 of Figure 26. The multi-core writing instrument 100 differs from the multi-core writing instrument 1 described above in that it does not have the cover member 12, first erasing member 60, or second erasing member 70, but instead has a holding member 90 that is provided at the rear end of the multi-core writing instrument 100 and can hold an item.

[0094] The retaining member 90 is a cylindrical or columnar member provided at the rear end of the barrel 4. The retaining member 90 is formed integrally with the inner tube 5. The retaining member 90 may be formed integrally with the rear axle 3, or may be a separate member from the rear axle 3 or the inner tube 5. A slit 92 is provided in the flat rear end surface of the retaining member 90, dividing the retaining member 90 equally into a pair of halves 91 along the central axis. The slit 92 is provided from the rear end surface of the retaining member 90 to the rear end surface of the rear axle 3. The slit 92 may be provided up to just before reaching the rear end surface of the rear axle 3.

[0095] An article can be inserted into the slit 92 in accordance with the width of the slit 92, and the article can be sandwiched between the pair of halves 91. As a result, the holding member 90 can detachably hold the article. By holding an article to be used together with the multi-core writing instrument 100 in the holding member 90 of the multi-core writing instrument 100, there is no need to worry about where to put or arrange the article.

[0096] The holding member 90 may be a separate member and replaceable with respect to the barrel 4, so that the holding member 90 can be replaced depending on the article. This allows the holding member 90 to securely hold a variety of articles. The holding member 90 may have cross-shaped or radial slits that intersect at right angles at the center of the rear end surface of the holding member 90. The holding member 90 may hold an article in a manner other than clamping it with the slits 92. For example, instead of the slits 92, the holding member 90 may have circular or polygonal mounting holes extending in the axial direction.

[0097] Any object may be used as long as it can be held by the holding member 90. The object inserted into the slit 92 may be, for example, a piece of memo paper, or, as shown in FIGS. 26 and 27 , a pick G, which is a tool used to play a plucked string instrument such as a guitar. The pick G is, for example, a flat pick held between the fingers when playing. The width of the slit 92 in the holding member 90 is preferably slightly smaller than the thickness of the pick G so that the pick G can be held without falling out. For example, if the thickness of the pick G is 0.8 mm, the width of the slit 92 is 0.7 mm. The pick G shown in FIGS. 26 and 27 is approximately triangular, but it may also be other shapes, such as a deerdrop shape.

[0098] When using the multi-core writing instrument 100 while composing or playing music using an instrument that uses a pick G, there is no need to worry about where to place or arrange the pick G. As a result, the pick G is prevented from being lost. In addition, it is easy to switch between the pick G and the multi-core writing instrument 100, making it easy to handle.

[0099] The pick G is usually made of celluloid, Ultem, nylon, tortoiseshell, polyacetal, acrylic, carbonate, metal, wood, etc., but the pick G may also be an erasing member that erases handwriting made with a ballpoint pen refill 6 or an erasing portion that erases handwriting made with a mechanical pencil refill 7. Therefore, the pick G may also be a friction member that can erase handwriting made with a thermochromic refill.

[0100] When Big G is used as a friction member, it is preferable that Pick G has a hardness of 60 to 70 as measured with a durometer hardness tester in accordance with JIS K6253, and a coefficient of friction of 0.25 to 0.35. This allows the thermochromic ink writing to be discolored when rubbed against a non-thermochromic ink writing that is close to the thermochromic ink writing, or a non-thermochromic ink writing that is superimposed on the thermochromic ink writing, while the appearance of the non-thermochromic ink writing can be sufficiently maintained. The coefficient of friction was measured using a surface property measuring instrument: HEIDON-16F manufactured by Shinto Scientific Co., Ltd., under conditions of 100 mm / min and a load of 0.98 N, using writing paper A (former JIS P3201: high-quality paper made from 100% chemical pulp, basis weight range 40 to 157 g / m). ２ The coefficient of friction (frictional force / load) was measured when rubbing a surface (whiteness of 75.0% or more) of the friction member with the paper. Other measurement conditions were a standard environment (25°C, 60%), a speed of 4 m / min, a travel distance of 10 cm, an angle of 90° between the normal to the tip of the friction member and the paper surface, machine sampling intervals of 0.001 seconds, and the force measured from the start of measurement until 0.3 seconds after the start of measurement was not used in calculating the coefficient of friction.

[0101] The configurations of the above-described embodiments may be applied to a writing instrument that accommodates only one refill in the barrel. Furthermore, the relationship between the imaginary tangent line T and the writing part and the holding member described above may be applied not only to the above-described knock-type writing instrument, particularly to knock-type multi-core writing instruments, but also to writing instruments in general, such as cap-type writing instruments.

[0102] REFERENCE SIGNS LIST 1 multi-core writing implement 2 front barrel 3 rear barrel 4 barrel tube 5 inner tube 6 ballpoint pen refill 7 mechanical pencil refill 8 connecting member 9 front end opening 10 window hole 11 guide rail 12 cover member 13 coil spring 14 spacer 15 weight body 16 step portion 17 annular member 18 holding projection 20 first knock member 21 operating portion 22 rail projection 23 first insertion portion 24 holding portion 25 flange portion 26 front cam 27 rear cam 28 locking projection 30 insertion member 31 display portion 32 sealing surface

Claims

1. A writing instrument comprising a shaft cylinder, at least one refill accommodated in the shaft cylinder, at least one knock member connected to the at least one refill and protruding radially outward from a side surface of the shaft cylinder, and at least one display portion provided on the at least one knock member so as to be visible from the front in the axial direction and invisible from the rear in the axial direction.

2. The writing instrument according to claim 1, wherein the operation portion has a top portion that protrudes most radially outward, the display portion is provided closer to the front than the top portion, and the display portion is formed in a protruding shape protruding from a surface of the knock member.

3. The writing instrument according to claim 1 or 2, further comprising a clip member, wherein the at least one knock member is configured to be fitted with the clip member, and a rear end portion of the at least one knock member fitted with the clip member protrudes rearward through the clip member.

4. The at least one refill has a first refill capable of writing a handwriting with a thermochromic ink and a second refill capable of writing a handwriting other than the handwriting with the thermochromic ink, and further comprises a first erasing member capable of erasing the handwriting by the first refill, a second erasing member capable of erasing the handwriting by the second refill, and a cover member capable of being fitted with the shaft cylinder. One of the first erasing member or the second erasing member is disposed at a rear end portion of the shaft cylinder and covered with the cover member. The writing instrument according to claim 1 or 2.

5. The writing instrument according to claim 1 or 2, further comprising a weight body disposed in the shaft cylinder between a position 20 mm from a tip of the refill in a writing state and a position half of the total length of the writing instrument. The center of gravity of the writing instrument is located between a position 20 mm from the tip of the refill and a position half of the total length of the writing instrument, and the weight between a position 20 mm from the tip of the refill and a position half of the total length of the writing instrument is configured to be 50% or more of the total weight of the writing instrument.

6. The writing instrument according to claim 1 or 2, wherein the shaft cylinder is a resin molded product, and at least a part of an outer surface of the shaft cylinder is provided with a leather grain pattern.

7. The writing instrument according to claim 1 or 2, wherein the at least one refill has a plurality of refills, each of the plurality of refills has a writing portion, and the shape, color, pattern, and gloss of the writing portion are different from each other according to the type or color of the handwriting by the plurality of refills.

8. The writing instrument according to claim 1 or 2, wherein a holding member capable of holding an article is provided at the rear end portion of the writing instrument.

9. The writing instrument according to claim 8, wherein the article is a pick.

10. The writing instrument according to claim 1 or 2, wherein the at least one refill has a writing portion, and the shaft cylinder or the writing portion is configured such that a virtual tangent line at the front edge portion of the outer peripheral surface of the shaft cylinder passes through the writing instrument in a writing state.

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