Retractable writing instrument

Abstract

To provide a knock type writing utensil with a simple mechanism that enables stable scratching movement.SOLUTION: A knock type writing utensil 1 comprises a barrel 4 and an operation part. A knocking operation in which the operation part is pushed forward, can switch between a writing state and a non-writing state. The knock type writing utensil further comprises: a brake rod 90 capable of being laterally moved in the barrel 4 by gravity; a knock ring 100 movable together with the operation part and rotatable about a center axis; and a locking part lockable with the knock ring 100. Arranging a forward end of the barrel 4 to face upward causes the brake rod 90 to move backward, so that rotation of the knock ring 100 is restricted to lock the knock ring 100 with the lock part, thereby blocking the operation part from moving forward.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This invention relates to a retractable writing instrument. [Background technology]

[0002] A known type of writing instrument has a knock-lock member that is movable in the front-to-back direction within the barrel by gravity and is formed in a cylindrical shape (Patent Document 1). In the knock-type writing instrument described in Patent Document 1, when the front end is facing upward, the knock-lock member is locked, which prevents the forward movement of the operating part located at the rear end of the barrel, thus preventing the knock operation. Therefore, when erasing writing with the knock-type writing instrument using the erasing member provided at the rear end of the operating part, a stable rubbing action can be performed. In other words, even if the holder changes their grip on the knock-type writing instrument and presses the erasing member against the writing surface to perform a rubbing action, the erasing member does not rattle. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-107615 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In the retractable writing instrument described in Patent Document 1, the cylindrical retractable locking member moves in the front-rear direction over a predetermined distance near the inner circumferential surface of the barrel due to gravity, which imposes constraints on the shape of the internal mechanism's components and their placement. To broaden the design possibilities of the internal mechanism, it is preferable to prevent the forward movement of the operating part when its front end is facing upward using other mechanisms as well.

[0005] The present invention aims to provide a retractable writing instrument equipped with a simple mechanism that enables stable scratching and other similar actions. [Means for solving the problem]

[0006] According to one aspect of the present invention, a knock-type writing instrument is provided, comprising a barrel and an operating part, wherein a writing state and a non-writing state can be switched by performing a knock operation to press the operating part forward, further comprising a brake member that can move in the front-rear direction within the barrel by gravity, a rotating member that moves together with the operating part and can rotate about a central axis, and a locking part that can lock with the rotating member, wherein when the front end of the barrel is turned upward, the brake member moves backward, restricting the rotation of the rotating member and locking the rotating member with the locking part, thereby preventing the operating part from moving forward.

[0007] The rotating member may be a cylindrical member. A projection may be provided on the inner surface of the rotating member, and the rotation of the rotating member may be restricted by the brake member inserted into the rotating member engaging with the projection. The rotating member may have a first inclined surface that is inclined circumferentially with respect to a plane perpendicular to the front-rear direction, and the locking portion may have a second inclined surface that is inclined circumferentially with respect to a plane perpendicular to the front-rear direction, and the forward movement of the operating portion may be prevented by the first inclined surface of the rotating member, whose rotation is restricted, coming into contact with the second inclined surface of the locking portion. The first inclined surface or the second inclined surface may have an inclination angle greater than 45 degrees with respect to the axial direction of the knock-type writing instrument. The writing instrument may comprise a plurality of writing bodies, a sliding member to which each of the writing bodies is connected, and a first cam surface positioned in front of the sliding member and cooperating with each of the sliding members, and in the writing state, at least one of the sliding members and the first cam surface may be spaced apart. All or part of the aforementioned operating section may be an erasing section capable of erasing the writing of the retractable writing instrument. [Effects of the Invention]

[0008] According to aspects of the present invention, a common effect is to provide a retractable writing instrument equipped with a simple mechanism that enables stable scratching and other similar actions. [Brief explanation of the drawing]

[0009] [Figure 1] Perspective view of a writing instrument according to an embodiment of the present invention. [Figure 2] Longitudinal sectional view of the writing instrument in a non-writing state with the front end facing downward. [Figure 3] Longitudinal sectional view of the writing instrument in a writing state with the front end facing downward. [Figure 4] Enlarged longitudinal sectional view of the writing instrument with the front end facing upward. [Figure 5] Partial cross-sectional perspective view of the rear portion of the writing instrument. [Figure 6] Perspective view of the rear portion of the writing instrument in a non-writing state. [Figure 7] Perspective view of the opposite side of the writing instrument in FIG. 6. [Figure 8] Longitudinal sectional view of the rear shaft. [Figure 9] Longitudinal sectional view of the inner cylinder. [Figure 10] Perspective view of the spacer. [Figure 11] Perspective view of the collar. [Figure 12] Rear view of the rotary cam. [Figure 13] Perspective view of the sliding piece. [Figure 14] Perspective view of the operating member. [Figure 15] Perspective view of the rotor. [Figure 16] Perspective view of the brake rod. [Figure 17] Perspective view of the knock ring. [Figure 18] Schematic diagram for explaining the operation of the knock ring. [Figure 19] ] Cross-sectional view for explaining the operation of the brake rod. [Figure 20] Another schematic diagram for explaining the operation of the knock ring. [Figure 21] Another schematic diagram for explaining the operation of the knock ring. [Figure 22] Schematic diagram for explaining the operation of the refill during a knock operation. [Figure 23]This is a schematic diagram illustrating the switching operation of the retractable refills. [Figure 24] This is a schematic diagram illustrating the operation of the refill during a knocking operation in another embodiment. [Figure 25] This is a perspective view of a writing instrument according to another embodiment of the present invention. [Figure 26] This is a longitudinal cross-section of the rear axle. [Figure 27] This is a perspective view of the spacer. [Figure 28] This is a schematic diagram illustrating the movement of the refill when the pen is knocked. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. Throughout all drawings, corresponding components are denoted by the same reference numerals.

[0011] Figure 1 is a perspective view of a writing instrument 1 according to an embodiment of the present invention; Figure 2 is a longitudinal cross-sectional view of the writing instrument 1 in a non-writing state with its front end facing downwards; Figure 3 is a longitudinal cross-sectional view of the writing instrument 1 in a writing state with its front end facing downwards; Figure 4 is an enlarged longitudinal cross-sectional view of the writing instrument 1 with its front end facing upwards; Figure 5 is a partial cross-sectional perspective view of the rear of the writing instrument 1; Figure 6 is a perspective view of the rear of the writing instrument 1 in a non-writing state; and Figure 7 is a perspective view of the opposite side of the writing instrument 1 shown in Figure 6.

[0012] The writing instrument 1 has a barrel 4 formed in a cylindrical shape and comprising a front barrel 2 and a rear barrel 3, and a plurality of refills 5 which are writing bodies arranged inside the barrel 4 and each having a writing section 5a at one end. The front barrel 2 and the rear barrel 3 may be formed as a single unit. Note that in Figures 6 and 7, the rear barrel 3 is omitted from the illustration.

[0013] In this specification, the side with the writing section 5a is defined as the "front" side, and the side opposite to the writing section 5a is defined as the "rear" side, in the axial direction of the writing instrument 1. Unless otherwise specified, the central axis or axial direction refers to the central axis or axial direction of the writing instrument 1.

[0014] The writing instrument 1 is a click-type writing instrument in which the refill 5 extends and retracts from the barrel 4 by a knock operation, which involves pressing the operating part forward. The writing instrument 1 is also a multi-core writing instrument that has multiple refills 5.

[0015] The writing instrument 1 has an inner cylinder 20 attached to the rear end of the rear shaft 3 and equipped with a clip 28. The inner cylinder 20 may also be referred to as the barrel 4. Inside the barrel 4, the writing instrument 1 has a spacer 30, a collar member 40 arranged around the spacer 30, a rotating cam 50 arranged behind the collar member 40, a plurality of sliding members, which are sliding sprockets 60, arranged between the inner cylinder 20 and the collar member 40, an operating member 70 arranged behind the spacer 30, a rotor 80 arranged around the operating member 70, a brake rod 90 arranged inside the operating member 70, and a knock ring 100 arranged around the operating member 70 behind the rotor 80.

[0016] An erasing member 7 is attached to the rear end of the operating member 70 via a holding member 6. A cover member 8 is detachably attached to the holding member 6, and the erasing member 7 is covered by the cover member 8. The erasing member 7 is integrally provided with respect to the holding member 6 by adhesive or two-color molding. The erasing member 7 may be detachably attached to the holding member 6, or a part of the holding member 6 may function as the erasing member. By pressing the cover member 8 forward when attached, or the erasing member 7 when the cover member 8 is removed, the operating member 70 moves forward, and the knocking operation is performed. In other words, the rear end of the writing instrument 1, i.e., the erasing member 7 or the cover member 8, functions as an operating part for the knocking operation. Note that all or part of the operating part may be an erasing part capable of erasing the writing of the writing instrument 1. In Figures 4 and 5, the cover member 8 is omitted.

[0017] The retaining member 6 is biased rearward by the rear spring 10. Therefore, whether the writing instrument 1 is in writing mode or not, the retaining member 6, the erasing member 7, and the cover member 8 are always positioned in the same location in the axial direction. The rear spring 10 may be omitted. A front spring 11 is positioned in front of the color member 40, and the color member 40 is biased rearward by the front spring 11. An annular display member 12 is positioned between the front shaft 2 and the rear shaft 3. The outer surface of the display member 12 is provided with two triangular marks that point in opposite directions in the circumferential direction.

[0018] In Figures 2 to 4, the upper direction is vertically upward, and the lower direction is vertically downward. That is, gravity acts downward in each figure. As will be described later, the brake rod 90 is movable in the front-rear direction within the barrel 4 due to gravity. Therefore, in Figures 2 and 3, since the front end of the writing instrument 1, i.e., the front end of the barrel 4, is facing downward, the brake rod 90 is positioned towards the front end within the barrel 4. On the other hand, in Figure 4, since the front end of the writing instrument 1 is facing upward, the brake rod 90 is positioned towards the rear end within the barrel 4 compared to Figures 2 and 3.

[0019] The configuration of the main components will be explained with reference to Figures 1 through 7 as appropriate.

[0020] Figure 8 is a longitudinal cross-sectional view of the rear shaft 3. In the assembled state of the writing instrument 1, the rear shaft 3 is positioned such that its upper side is the rear side of the writing instrument 1 in Figure 8. Two roughly T-shaped protrusions 13 are provided on the inner circumferential surface of the rear shaft 3 as locking parts. The two T-shaped protrusions 13 are spaced 120 degrees apart around the central axis. Multiple annular grooves 14 spaced apart in the axial direction are formed on the inner circumferential surface of the front end of the rear shaft 3. Note that the T-shaped protrusions 13 may be provided not on the inner circumferential surface of the rear shaft 3, but for example, as a separate component.

[0021] Figure 9 is a longitudinal cross-sectional view of the inner cylinder 20. In the assembled state of the writing instrument 1, the inner cylinder 20 is positioned such that its upper side is the rear side of the writing instrument 1 in Figure 9. The inner cylinder 20 is attached to the rear end of the rear shaft 3 by fitting or press-fitting. A stepped portion 21 facing the rear is formed on the inner circumferential surface of the inner cylinder 20. Six first inner protrusions 22 extending in the axial direction are provided at equal intervals along the circumferential direction on the inner circumferential surface of the inner cylinder 20 in front of the stepped portion 21. An inclined surface 22a is formed on the front end surface of each of the first inner protrusions 22, which is inclined in the circumferential direction. The six first inner protrusions 22 constitute the first outer cam 23. A second inner protrusion 24 that protrudes further than the first inner protrusion 22 is formed at the rear end of each of the first inner protrusions 22 as a locking portion. Each of the rear end faces of the second inner projection 24 has a circumferentially inclined slope 24a, and a portion of the front end face of each of the second inner projections 24 has a circumferentially inclined partial slope 24b (see Figure 18(A) described later). The six second inner projections 24 constitute the second outer cam 25. A rectangularly cut-out recess 26 is formed at the front end of the inner cylinder 20.

[0022] Figure 10 is a perspective view of the spacer 30. In the assembled state of the writing instrument 1, the spacer 30 is positioned such that its upper side is at the rear of the writing instrument 1 in Figure 10. The spacer 30 has a cylindrical body portion 31, three rail portions 32 extending rearward from the rear end of the body portion 31, and a connecting portion 33 formed to connect the rear ends of the three rail portions 32. The connecting portion 33 has two connecting portion pieces 33a whose outer circumference is smaller than the outer diameter of the three rail portions 32, and one rotation restricting piece 33b formed as an extension of the rail portions 32 or with a larger diameter than the connecting portion pieces 33a. Three grooves into which the refill 5 can be inserted are defined by two adjacent rail portions 32 and the connecting portion 33. In other words, in this embodiment, the writing instrument 1 can accommodate three refills 5. A flange portion 34 is formed on the outer circumferential surface of the body portion 31, and the flange portion 34 divides the outer circumferential surface of the body portion 31 into front and rear sections. A projection-shaped mark portion 35 extending forward is formed on the front end surface of the flange portion 34. The mark portion 35 fits into a recess of the display member 12 (Figure 1). A male thread portion 36 is formed on the front of the main body portion 31, and the spacer 30 is screwed into the front shaft 2 by the male thread portion 36. Multiple annular projections 37 spaced apart in the axial direction are formed on the rear of the main body portion 31.

[0023] Figure 11 is a perspective view of the color member 40. In the assembled state of the writing instrument 1, the color member 40 is positioned such that its upper side is at the rear of the writing instrument 1 in Figure 11. The color member 40 is formed in a cylindrical shape overall. Two T-shaped recesses 41 are formed on the outer circumferential surface of the color member 40, corresponding to the T-shaped projection 13 of the rear shaft 3 and having complementary shapes. A stepped raised portion 42 is formed on the rear end surface corresponding to the space between the two T-shaped recesses 41. A notch 43 is formed on a part of the rear end surface of the color member 40, cut diagonally from the rear end towards the front (Figure 7). The rear end surface of the color member 40, including the end face of the notch 43, constitutes the first cam surface 44.

[0024] Figure 12 is a rear view of the rotating cam 50. In the assembled state of the writing instrument 1, the rotating cam 50 is positioned such that its upper side is at the rear of the writing instrument 1 in Figure 12. The rotating cam 50 has an annular portion 51 formed in an annular shape around its central axis and a claw-shaped claw portion 52. The annular portion 51 is formed to be attached to the inner surface of the rear end of the claw portion 52. A protruding guide projection 53 is formed on the inner surface of the claw portion 52, extending forward from the front end surface of the annular portion 51. As shown in Figure 7, the outer shape of the rear part of the claw portion 52 is formed in a rectangle complementary to the recess 26 of the inner cylinder 20. Therefore, in the writing instrument 1 in a non-writing state, the claw portion 52 fits into the recess 26 of the inner cylinder 20, and the outer surface of the rotating cam 50 is flush with the outer surface of the inner cylinder 20. In addition, the outer diameter of the annular portion 51 is formed to be slightly smaller than the inner diameter of the inner cylinder 20. The front portion of the claw portion 52 has a flat surface 54 that is formed flat and an end surface 55 that is formed at an angle. The flat surface 54 and the end surface 55 of the claw portion 52 together with the front end surface 27 (Figure 9) of the inner cylinder 20 constitute the second cam surface 56.

[0025] Figure 13 is a perspective view of the sliding ring 60. In the assembled state of the writing instrument 1, the sliding ring 60 is positioned such that its upper side is at the rear of the writing instrument 1 in Figure 13. The sliding ring 60 has an insertion portion 61 that is inserted into the rear end of the refill 5, and a slider 62 formed on the side surface of the insertion portion 61. As the slider 62 slides along the first cam surface 44 as will be described later, a minute projection 63 is formed on the front end surface of the slider 62 to reduce frictional resistance during sliding. As the slider 62 slides along the second cam surface 56, a similar minute projection may be formed on the rear end surface of the slider 62.

[0026] Figure 14 is a perspective view of the operating member 70. In the assembled state of the writing instrument 1, the operating member 70 is positioned such that its upper side is the rear side of the writing instrument 1 in Figure 14. The operating member 70 is a hollow member with an open front end and a closed rear end. A cam flange 71 is formed on the outer circumferential surface of the operating member 70. A rotating cam surface 72 consisting of symmetrical and continuous peaks and valleys is formed on the front end surface of the cam flange 71. Six guide grooves 73 extending in the axial direction are formed on the outer circumferential surface of the cam flange 71 at equal intervals along the circumferential direction. On the outer circumferential surface of the operating member 70 behind the cam flange 71, two rectangular through holes 74 extending in the axial direction are formed, spaced 180 degrees apart around the central axis. On the outer circumferential surface of the operating member 70, a rearward-facing step portion 75 is formed behind the through holes 74, and a fitting projection 76 is formed behind the step portion 75. When the retaining member 6 is attached to the rear end of the operating member 70, the fitting projection 76 fits into the opening provided in the retaining member 6.

[0027] Figure 15 is a perspective view of the rotor 80. In the assembled state of the writing instrument 1, the rotor 80 is positioned such that its upper side is the rear side of the writing instrument 1 in Figure 15. The rotor 80 is a cylindrical member. A rotating cam receiving surface 81 is formed on the rear end surface of the rotor 80, which is complementary to the rotating cam surface 72 of the operating member 70. The rotating cam receiving surface 81 cooperates with the rotating cam surface 72 of the operating member 70. Six protrusions 82 are formed on the outer circumferential surface of the rotor 80, extending in the axial direction and arranged at equal intervals along the circumferential direction, and the rear end surfaces of the protrusions 82 constitute the first inner cam 83. Two adjacent protrusions 82 define six locking grooves 84 that extend in the front-rear direction. A locking portion 85 is formed on the rear end surface of each protrusion 82.

[0028] Figure 16 is a perspective view of the brake rod 90. In the assembled state of the writing instrument 1, the brake rod 90 is positioned such that its upper part is at the rear of the writing instrument 1 in Figure 16. The brake rod 90 is a solid member. A small diameter portion 91 is formed at the rear end of the brake rod 90, and a larger diameter portion 92 is formed in front of the small diameter portion 91. The small diameter portion 91 and the large diameter portion 92 are connected by a tapered surface 93. Two rectangular protrusions 94 are formed on the outer circumferential surface of the large diameter portion 92, extending axially and spaced 180 degrees apart around the central axis. A regulating portion 95 is defined by cutting out a rectangular portion of the rear of each protrusion 94.

[0029] Figure 17 is a perspective view of the knock ring 100. In the assembled state of the writing instrument 1, the knock ring 100 is positioned such that its upper side is at the rear of the writing instrument 1 in Figure 17. The knock ring 100 is a cylindrical member. Two regulating protrusions 101 are formed on the inner circumferential surface of the knock ring 100, extending axially and spaced 180 degrees apart around the central axis. Four right-angled triangular first outer protrusions 102 are formed on the outer circumferential surface of the front end of the knock ring 100. Two of the first outer protrusions 102 are spaced 60 degrees apart around the central axis, and the other two corresponding first outer protrusions 102 are spaced 180 degrees apart from each other around the central axis. Behind each of the first outer protrusions 102, a parallelogram-shaped second outer protrusion 103 is formed. The first outer protrusions 102 and the second outer protrusions 103 constitute the second inner cam 104.

[0030] Next, the combination and arrangement of each component in writing instrument 1 will be explained with reference to Figures 1 to 7.

[0031] The spacer 30 is screwed to the front shaft 2 by a male threaded portion 36. The front end of the rear shaft 3 is inserted into the rear of the main body portion 31 of the spacer 30. At this time, each of the annular projections 37 of the spacer 30 fits into the corresponding annular groove 14 of the rear shaft 3, thereby connecting the rear shaft 3 to the spacer 30 and, consequently, the front shaft 2, so that it can rotate without easily coming loose. The front spring 11 and the collar member 40 are arranged around the rail portion 32 of the spacer 30. The front end of the front spring 11 is supported by the rear end surface of the main body portion 31 of the spacer 30, and the rear end of the front spring 11 is in contact with the front end surface of the collar member 40. The collar member 40 is movable in the front-rear direction and is biased rearward by the front spring 11. Each of the T-shaped projections 13 of the rear shaft 3 is housed in the corresponding T-shaped recess 41 of the collar member 40, thereby restricting the rotation of the collar member 40 around its central axis. Therefore, when the rear axle 3 is rotated relative to the front axle 2, the collar member 40 rotates together with the rear axle 3.

[0032] The refills 5 and the sliding rings 60 are connected by inserting the insertion portion 61 of the sliding ring 60 into the rear end of each of the three refills 5. In this state, each of the refills 5 is inserted into the groove between the rail portions 32 of the spacer 30 and is movable in the front-rear direction. At this time, the slider 62 of the sliding ring 60 protrudes radially outward from the rail portion 32 of the spacer 30. The slider 62 engages with the edge of the rail portion 32, preventing the refill 5 from falling out between the rail portions 32. The slider 62, in particular the minute projection 63 of the slider 62, is in contact with the first cam surface 44 of the collar member 40. At this time, one of the sliders 62 of the three sliding rings 60 is positioned on the first cam surface 44 of the notch portion 43 of the collar member 40, and the remaining sliders 62 are positioned on the first cam surface 44 of the rear end surface of the collar member 40.

[0033] Since the collar member 40 is biased rearward by the front spring 11, each of the sliding pieces 60 is also biased rearward via the collar member 40, and furthermore, the rotating cam 50 is also biased rearward via the sliding pieces 60. The rearward movement of the collar member 40, and by extension the sliding pieces 60, is restricted by the rear end surface of the slider 62 contacting the second cam surface 56 of the rotating cam 50, which includes the front end surface 27 of the inner cylinder 20. Therefore, each of the sliders 62 of the sliding pieces 60 is positioned between the first cam surface 44 and the second cam surface 56. The claw portion 52 of the rotating cam 50 is movable in the front-rear direction within the recess 26 of the inner cylinder 20. At this time, the annular portion 51 of the rotating cam 50 slides along the inner circumferential surface of the inner cylinder 20.

[0034] The operating member 70 is positioned inside the barrel 4 such that each of the first inner projections 22 of the inner cylinder 20 is positioned in the corresponding guide groove 73. This allows the operating member 70 to move back and forth within the barrel 4 without rotating during the knocking operation. The front end of the rear spring 10 is supported by the stepped portion 21 of the inner cylinder 20, and the rear end of the rear spring 10 is in contact with the retaining member 6. As a result, the rear spring 10 biases the retaining member 6, and by extension the operating member 70 to which the retaining member 6 is attached, backward. The backward movement of the operating member 70 is restricted by the rear end surface of the cam flange 71 contacting the front end surface of the second inner projection 24 of the inner cylinder 20.

[0035] A rotor 80 is positioned on the outer circumferential surface of the operating member 70 in front of the cam flange 71 so as to be movable and rotatable in the front-rear direction. At this time, the first inner cam 83 of the rotor 80 is positioned to cooperate with the first outer cam 23 of the inner cylinder 20. In the writing instrument 1 in a non-writing state (Figure 2), the front end of the rotor 80 is inserted into the annular portion 51 of the rotating cam 50, and the front end surface of the projection 82 of the rotor 80 is in contact with the rear end surface of the annular portion 51 of the rotating cam 50. At this time, the rear end surface of the rotor 80, i.e., the rotating cam receiving surface 81, is in contact with the rotating cam surface 72 of the operating member 70. As described above, since the rotating cam 50 is biased rearward by the front spring 11 via the sliding piece 60, the rotor 80, and by extension the operating member 70 in contact with it, are also biased rearward.

[0036] The brake rod 90 is located inside the operating member 70, and consequently inside the rotor 80. The brake rod 90 is movable in the front-rear direction within the operating member 70 by gravity. The forward movement of the brake rod 90 is restricted by contact with the rear end surface of the spacer 30, i.e., the rear end surface of the connecting portion 33. The backward movement of the brake rod 90 is restricted by the tapered surface 93 of the brake rod 90 engaging with the inner surface of the operating member 70 (Figure 4).

[0037] A knock ring 100 is rotatably positioned around the through hole 74 of the operating member 70, and the knock ring 100 is integrally movable in the front-rear direction together with the operating member 70. Specifically, the knock ring 100 is positioned between the cam flange 71 of the operating member 70 and the retaining member 6 attached to the operating member 70, and its movement in the front-rear direction relative to the operating member 70 is restricted. At this time, as will be described later with reference to Figure 19, each of the restricting projections 101 of the knock ring 100 is positioned within the corresponding through hole 74 of the operating member 70, so that the knock ring 100 is rotatable within a predetermined angle range within the through hole 74. Furthermore, the second inner cam 104 of the knock ring 100 is positioned to cooperate with the second outer cam 25 of the inner cylinder 20.

[0038] Next, we will explain the operation of writing instrument 1.

[0039] The writing instrument 1 switches between writing and non-writing states by performing a knock operation, which involves pressing the operating part at the rear end of the writing instrument 1 forward against the biasing force of the rear spring 10 and the front spring 11. The basic operation of this operation will be explained below. The switching between writing and non-writing states is performed by the cooperation of the rotating cam surface 72 of the operating member 70 and the rotating cam receiving surface 81 of the rotor 80, which in turn causes the first inner cam 83 of the rotor 80 and the first outer cam 23 of the inner cylinder 20 to cooperate. The cooperative operation between these cams is the same as that of conventional knock-type writing instruments, so it will be briefly explained below.

[0040] In the non-writing state, the rotor 80's rotation is restricted because each of the projections 82 is positioned between the first inner projections 22 of the inner cylinder 20. In other words, the first inner projections 22 of the inner cylinder 20 are positioned within the locking grooves 84 of the rotor 80. Therefore, the rotation of the rotor 80 is restricted. At this time, the rotating cam surface 72 of the operating member 70 and the rotating cam receiving surface 81 of the rotor 80 are in contact, but their phases are offset from each other.

[0041] When the operating member 70 moves forward due to the knocking operation, the rotor 80 moves forward, pressed by the cam flange 71. As the rotor 80 moves forward, the sliding piece 60, which has a slider 62 positioned in the notch 43 of the collar member 40, and the collar member 40 itself move forward, pressed by the claw portion 52. As a result, the refill 5 connected to this sliding piece 60 protrudes from the barrel 4.

[0042] As the rotor 80 moves forward, and the rear end of the projection 82 passes the front end of the first inner projection 22 of the inner cylinder 20 in the front-rear direction, the restriction on the rotation of the rotor 80 is released. At that moment, a circumferential component force acts to restore the phase difference between the rotating cam surface 72 of the operating member 70 and the rotating cam receiving surface 81 of the rotor 80, and this component force causes the rotor 80 to rotate slightly.

[0043] Next, when the knocking operation is stopped, the biasing force of the front spring 11 causes the sliding wheel 60, rotating cam 50, rotor 80, and operating member 70 to move slightly backward via the collar member 40. At this time, the first inner cam 83 of the rotor 80 and the first outer cam 23 of the inner cylinder 20 cooperate to further rotate the rotor 80. That is, the inclined surface 22a of the first inner projection 22 of the inner cylinder 20 and the rear end surface of the projection 82 of the rotor 80, which are inclined surfaces in the same direction, come into contact, and a circumferential component force acts, causing the rotor 80 to rotate slightly further. Due to this rotation, the phase between the rotating cam surface 72 of the operating member 70 and the rotating cam receiving surface 81 of the rotor 80 is shifted again. The rotation and backward movement of the rotor 80 are restricted by the first inner projection 22 of the inner cylinder 20 engaging with the locking portion 85 of the rotor 80. As a result, refill 5 remains protruding from barrel 4, and writing instrument 1 is in the writing position.

[0044] To switch from the writing state to the non-writing state, the knocking operation is performed again. When the operating member 70 moves forward due to the knocking operation, the rotor 80 moves forward due to being pressed by the cam flange 71. When the rotor 80 moves forward and the rear end of the projection 82 passes the front end of the first inner projection 22 of the inner cylinder 20 in the front-rear direction, the restriction on the rotation of the rotor 80 is released. At that moment, a circumferential component force acts to restore the phase difference between the rotating cam surface 72 of the operating member 70 and the rotating cam receiving surface 81 of the rotor 80, and this component force causes the rotor 80 to rotate slightly.

[0045] Next, when the knocking operation is stopped, the biasing force of the front spring 11 causes the sliding wheel 60, rotating cam 50, rotor 80, and operating member 70 to move slightly backward via the collar member 40. At this time, the first inner cam 83 of the rotor 80 and the first outer cam 23 of the inner cylinder 20 cooperate to further rotate the rotor 80. That is, the inclined surface 22a of the first inner projection 22 of the inner cylinder 20 and the rear end surface of the projection 82 of the rotor 80, which are inclined surfaces in the same direction, come into contact, and a circumferential component force acts, causing the rotor 80 to rotate slightly further. Due to this rotation, the phase between the rotating cam surface 72 of the operating member 70 and the rotating cam receiving surface 81 of the rotor 80 is shifted again. The rotation of the rotor 80 is restricted by each of the projections 82 of the rotor 80 being repositioned between the first inner projections 22 of the inner cylinder 20. The backward movement of the rotor 80 is restricted by the cam flange 71 of the operating member 70. As the rotor 80 moves backward, the collar member 40, the sliding wheel 60, and the rotating cam 50, which are biased by the front spring 11, also move backward. As a result, the refill 5 becomes retracted into the barrel 4, and the writing instrument 1 is in a non-writing state.

[0046] The knocking operation described above for switching between the writing and non-writing states is performed with the front end of the writing instrument 1 facing downwards. On the other hand, the knocking operation cannot be performed when the front end of the writing instrument 1 is facing upwards. That is, even if one attempts to push the operating part forward, the movement of the operating member 70 is prevented, and the operating member 70 cannot be moved forward. This will be explained below.

[0047] Figure 18 is a schematic diagram illustrating the operation of the knock ring 100. Figure 18 shows the positional relationship of the second inner cam 104 of the knock ring 100 with respect to the second outer cam 25 when it is unfolded in the circumferential direction, that is, the positional relationship between the second inner projection 24 of the inner cylinder 20 and the first outer projection 102 and second outer projection 103 of the knock ring 100. In Figure 18, the upper part is the rear side of the writing instrument 1, and the lower part is the front side of the writing instrument 1. Figure 18(A) shows the state before the knock operation is performed, Figure 18(B) shows the state immediately after the operating part begins to move forward due to the knock operation, Figure 18(C) shows the state after the operating part has moved forward due to the knock operation, and Figure 18(D) shows the state immediately before the operating part returns to its original position when the knock operation is stopped.

[0048] Referring to Figure 18(A), before the knocking operation is performed, the second inner projection 24 of the inner cylinder 20 is positioned in front of the second outer projection 103 of the knock ring 100. When the knocking operation is performed from this state, the operating member 70 moves forward relative to the inner cylinder 20, and therefore the knock ring 100 also moves forward. At this time, the second outer cam 25 of the inner cylinder 20 and the second inner cam 104 of the knock ring 100 cooperate to rotate the knock ring 100. That is, the inclined surface 24a of the second inner projection 24 of the inner cylinder 20 and the front end surface of the second outer projection 103 of the knock ring 100, which have inclined surfaces in the same direction, come into contact, and a circumferential component force acts, causing the knock ring 100 to rotate while moving forward (Figure 18(B)). As the operating member 70 moves further forward, the second inner projection 24 of the inner cylinder 20 passes alongside the second outer projection 103, allowing the knock ring 100 and, consequently, the operating member 70 to move sufficiently forward (Figure 18(C)), and the knocking operation is performed.

[0049] When the knocking operation is stopped from the state shown in Figure 18(C), the biasing force of the rear spring 10 causes the operating member 70 to move backward relative to the inner cylinder 20, and consequently the knock ring 100 also moves backward. At this time, the second outer cam 25 of the inner cylinder 20 and the second inner cam 104 of the knock ring 100 cooperate to rotate the knock ring 100 in the opposite direction to before. That is, the partial inclined surface 24b of the second inner projection 24 of the inner cylinder 20 and the rear end surface of the first outer projection 102 of the knock ring 100, which have inclined surfaces in the same direction, come into contact, and a circumferential component force acts, causing the knock ring 100 to rotate while retracting (Figure 18(D)). As a result, the knock ring 100, and consequently the operating member 70, return to their original positions (Figure 18(A)).

[0050] As described above, when the front end of the writing instrument 1 is facing downwards, the knock ring 100 rotates in response to the knock operation, allowing the operating member 70, i.e., the operating part, to move forward without being prevented from performing the knock operation. On the other hand, when the front end of the writing instrument 1 is facing upwards, the rotation of the knock ring 100 is restricted by the brake rod 90, preventing the operating part from moving forward and making it impossible to perform the knock operation. This knock lock mechanism will be explained with reference to Figure 19.

[0051] Figure 19 is a cross-sectional view illustrating the operation of the brake rod 90. Figure 19(A) is a cross-sectional view along line AA in Figure 3, where the front end of the writing instrument 1 is facing downwards, and Figure 19(B) is a cross-sectional view along line BB in Figure 4, where the front end of the writing instrument 1 is facing upwards.

[0052] As shown in Figure 19(A), when the front end of the writing instrument 1 is facing downwards, the restricting projections 101 of the knock ring 100 are positioned within the through-holes 74 of the operating member 70. Figure 19(A), like Figure 18(A), shows the state before the knocking operation is performed, and at this time, the restricting projections 101 are positioned towards one edge of the through-hole 74. Therefore, the knock ring 100 can rotate within a predetermined angle range, within the range of restriction that the restricting projections 101 receive from the edge of the through-hole 74.

[0053] As shown in Figure 19(B), when the front end of the writing instrument 1 is facing upward, the restricting projections 101 of the knock ring 100 are positioned within the through-holes 74 of the operating member 70, and the restricting portion 95 is positioned to fill the gap in the through-holes 74. That is, when the front end of the writing instrument 1 is turned upward, gravity causes the brake rod 90 to move backward. As a result, the brake rod 90 is inserted further inside the operating member 70, and the restricting portion 95 is inserted into the gap in the through-holes 74. Consequently, the restricting projections 101 of the knock ring 100 engage with the restricting portion 95 of the brake rod 90, thereby restricting the rotation of the knock ring 100.

[0054] If the knock ring 100 cannot rotate, as explained with reference to Figure 18(B), even if the inclined surface 24a of the second inner projection 24 of the inner cylinder 20 and the front end surface of the second outer projection 103 of the knock ring 100 come into contact, the knock ring 100 will not rotate. As a result, the second inner projection 24 of the inner cylinder 20 and the second outer projection 103 of the knock ring 100 are locked together, preventing the operating member 70 from moving any further forward. Therefore, when the front end of the writing instrument 1 is facing upward, the operating part is prevented from moving forward, and the knocking operation cannot be performed.

[0055] Furthermore, when the front end of the writing instrument 1 is changed from an upward position to a downward position, the brake rod 90 moves forward, and the restriction on the rotation of the knock ring 100 is released. As a result, the knocking operation can be performed again.

[0056] Since the forward movement of the operating part of the writing instrument 1 is prevented when the front end is facing upward, it is possible to perform a stable rubbing action when erasing writing with the writing instrument 1 using the erasing member 7, for example. In other words, even if the writing instrument 1 is held differently and the operating part is pressed against the writing surface to perform a rubbing action, the operating part will not rattle. The writing instrument 1 makes it possible to achieve a stable rubbing action with a simpler mechanism than conventional ones.

[0057] For example, the conventional knock-lock mechanism described in Patent Document 1 (Japanese Patent Publication No. 2016-107615) has a single knock-lock member, and is configured to prevent the forward movement of the operating part by the forward and backward movement and rotation of the knock-lock member due to gravity. In contrast, the knock-lock mechanism of writing instrument 1 has a brake rod 90 and a knock ring 100. Therefore, the brake rod 90 moves only due to gravity, and the knock ring 100 rotates only, thus separating the members responsible for movement and rotation. As a result, the knock-lock mechanism of writing instrument 1 can have a shorter overall length as a mechanism than the knock-lock mechanism of Patent Document 1, and the design of the internal mechanism's component shapes and placement locations, such as near the inner circumferential surface of the barrel, can be made more flexible.

[0058] The brake rod may be of any shape as long as it is able to move in the front-rear direction within the shaft cylinder by gravity. The knock ring may be a C-shape that is not a perfect ring, and may be a rotating member of any shape as long as it moves with the operating part and is able to rotate around its central axis. The brake member and rotating member can be of any shape as long as, when the front end of the shaft cylinder is pointed upward, the brake member moves backward, restricting the rotation of the rotating member and preventing the operating part from moving forward by engaging the rotating member with the locking part.

[0059] Incidentally, if the writing instrument 1 is accidentally dropped while its front end is facing upwards, a strong axial impact is applied to the operating part. At this time, the inclined surface 24a of the second inner projection 24 of the inner cylinder 20 collides with the front end surface of the second outer projection 103 of the knock ring 100, causing the second inner projection 24 to deform and bulge in the circumferential direction. As a result, the deformed second inner projection 24 may not be able to pass between adjacent second outer projections 103 of the knock ring 100, as shown in Figure 18(B), and the knocking operation may not be possible. Furthermore, even if the deformed second inner projection 24 could pass between adjacent second outer projections 103 of the knock ring 100, the deformed second inner projection 24 may get caught between the second outer projections 103, preventing the operating part from returning to its original position. This will be explained with reference to Figure 20.

[0060] Figure 20 is another schematic diagram illustrating the operation of the knock ring 100. Figure 20 is similar to Figure 18, where the upper part is the rear side of the writing instrument 1 and the lower part is the front side of the writing instrument 1. The knock ring 100 shown in Figure 20 has the second outer projection 103 that corresponds to the second inner projection 24 passing between the adjacent second outer projections 103, i.e., the second outer projection 103 on the right side of the figure, formed to be shorter in the axial direction. That is, the front end surface of the second outer projection 103 on the right side of the figure is formed to be positioned rearward than the front end surface of the other second outer projection 103.

[0061] Figure 20(A) shows the moment when the writing instrument 1 falls and the rear end surface of the second inner projection 24 of the inner cylinder 20, which does not pass between adjacent second outer projections 103, collides with the front end surface of the corresponding second outer projection 103 of the knock ring 100. At this time, the other second inner projection 24 of the inner cylinder 20 does not collide with the corresponding second outer projection 103 because its front end surface is positioned further back. In Figure 20(B), as a result of the collision, the second inner projection 24 of the inner cylinder 20 that does not pass between adjacent second outer projections 103 has a deformed portion 24c. At this time, the other second inner projection 24 of the inner cylinder 20 is not deformed, so it is able to pass between adjacent second outer projections 103 and does not affect the knocking operation.

[0062] Incidentally, during normal knocking operations, the rear end surface of the second inner projection 24 of the inner cylinder 20 and the front end surface of the second outer projection 103 of the knock ring 100 come into contact, which can cause the second inner projection 24 of the inner cylinder 20 and the second outer projection 103 of the knock ring 100 to engage with each other, preventing the knock ring 100 from rotating. This will be explained with reference to Figure 21.

[0063] Figure 21 is another schematic diagram illustrating the operation of the knock ring 100. Figure 21 is similar to Figure 18, where the upper part is the rear side of the writing instrument 1 and the lower part is the front side of the writing instrument 1. In Figure 21, by setting the angle α of the acute-angled portion at the front end of the second outer projection 103 of the knock ring 100, particularly the second outer projection 103 on the left side in the figure, to a range of 45 to 90 degrees, unintended engagement between the second inner projection 24 of the inner cylinder 20 and the second outer projection 103 of the knock ring 100 can be prevented.

[0064] As described above, the operation of the knock mechanism causes the operating member 70, rotor 80, and rotating cam 50 to move forward. When the rotating cam 50 moves forward, it is pressed by the claw portion 52, causing the sliding wheel 60, which has a slider 62 positioned in the notch portion 43 of the color member 40, and the color member 40 itself to move forward. As a result, the writing portion 5a of the refill 5 connected to this sliding wheel 60 protrudes from the barrel 4. The operation of protruding a predetermined refill 5 will be explained with reference to Figure 22.

[0065] Figure 22 is a schematic diagram illustrating the operation of the refill during the knocking operation. As described above, each of the sliders 62 of the sliding ring 60 is positioned between the first cam surface 44 and the second cam surface 56, and since these are shown unfolded in the circumferential direction in Figure 22, the left and right sides are connected in each figure. Each of the sliding rings 60 works in cooperation with the first cam surface 44 and the second cam surface 56. The circle mark attached to one of the three sliding rings 60 is a mark drawn for convenience to identify the sliding ring 60. In Figure 22, the top is the rear side of the writing instrument 1, and the bottom is the front side of the writing instrument 1. Figure 22(A) shows the color member 40, rotating cam 50, and sliding wheel 60 of the writing instrument 1 in a non-writing state; Figure 22(B) shows the color member 40, rotating cam 50, and sliding wheel 60 immediately after the knock operation begins; and Figure 22(C) shows the color member 40, rotating cam 50, and sliding wheel 60 of the writing instrument 1 in a writing state. In addition, the T-shaped projection 13 provided on the inner circumferential surface of the rear shaft 3 is schematically shown in Figure 22.

[0066] When the knocking operation is performed from the state shown in Figure 22(A), the forward movement of the operating member 70 causes the rotating cam 50 to also move forward, and the sliding piece 60 marked with a circle and the collar member 40, which are located in the notch 43, move forward. At this time, the remaining two sliding pieces 60 engage with the T-shaped projection 13 provided on the inner circumferential surface of the rear shaft 3, which is relatively stationary (Figure 22(B)). Therefore, it can be said that the first cam surface 44 includes the rear end surface of the T-shaped projection 13. Next, when the rotating cam 50 moves further, as described above, the first inner cam 83 of the rotor 80 and the first outer cam 23 of the inner cylinder 20 cooperate, and the writing instrument 1 enters the writing state (Figure 22(C)). At this time, the remaining two sliding pieces 60 do not move forward because they are engaged with the T-shaped projection 13 provided on the inner circumferential surface of the rear shaft 3.

[0067] If the T-shaped projection 13 were absent, other refills 5 besides the one protruding from the barrel 4 would also move forward due to gravity. This would cause multiple refills 5 to converge at the tapered portion at the front end of the front barrel 2, potentially hindering the movement of the refill 5 that is intended to protrude. Therefore, the writing instrument 1 is provided with a T-shaped projection 13 to lock other refills 5 into it, thereby restricting their unnecessary forward movement. Consequently, the T-shaped projection 13 can take any shape as long as it can lock the refills 5 into it.

[0068] As is clear from Figure 22, the knocking operation causes the refill 5 connected to the sliding ring 60, which is relatively forward among the three refills 5, to protrude from the front end opening of the barrel 4, and the writing instrument 1 enters the writing state. Therefore, by positioning the writing portion 5a of the relatively forward refill 5 near the front end opening of the barrel 4 when the writing instrument 1 is not writing, the refill 5 can be protruded and the writing state entered with a smaller knocking operation amount, i.e., a smaller knocking stroke. In addition, during the knocking operation, the second cam surface 56 of the rotating cam 50 itself moves forward and presses against the sliding ring 60, thereby suppressing rattle between parts. Furthermore, the rotating cam 50, especially the claw portion 52, can be a relatively large part, thereby increasing its strength.

[0069] Figure 23 is a schematic diagram illustrating the switching operation of the retractable refill 5, that is, the operation for changing the refill 5 used for writing. Figure 23 is similar to Figure 22, and in Figure 23, the upper part is the rear side of the writing instrument 1, and the lower part is the front side of the writing instrument 1. The spacer 30 is fixed to the front shaft 2. On the other hand, the inner cylinder 20, color member 40, rotating cam 50, and rear shaft 3 are rotatable relative to the front shaft 2 and constitute a rotation selection member. In other words, the front shaft 2 is rotatable relative to the rear shaft 3.

[0070] In Figure 23, for the sake of explanation, the rotation of the rear shaft 3 relative to the front shaft 2 is taken with the rear shaft 3 as the reference point. Therefore, in accordance with the rotation of the rear shaft 3, only the sliding ring 60 moves in the left-right direction in Figure 23. In reality, the sliding ring 60 only moves in the front-rear direction within the groove between the rail portions 32 of the spacer 30. Also for the sake of explanation, the three sliding rings 60 are distinguished as sliding ring 60A, sliding ring B, and sliding ring 60C. As described above, during the knocking operation, the refill 5 connected to the sliding ring 60 positioned in the notch portion 43 of the color member 40, i.e., the refill 5 positioned in the selected position, is pressed by the claw portion 52 and protrudes from the shaft 4. Therefore, by changing the refill 5 positioned in the selected position, the desired refill 5 can be extended and retracted. Furthermore, for the sake of explanation, the rear shaft 3 is assumed to be freely rotatable relative to the front shaft 2.

[0071] Figure 23(A) shows the writing instrument 1 in a non-writing state, with the sliding wheel 60A positioned in the forward position. When the knocking operation is performed in this state, the refill 5 connected to the sliding wheel 60A enters the writing state, as described above. At this time, the other sliding wheels 60B and 60C are locked to the T-shaped projection 13 provided on the inner circumferential surface of the rear shaft 3, as explained with reference to Figure 22, and their forward movement is restricted.

[0072] In the state shown in Figure 23(A), when the rear shaft 3 is rotated clockwise relative to the front shaft 2 when viewed from the rear of the writing instrument 1, each of the sliding wheels 60 moves relatively to the right in the figure. At this time, as the rear shaft 3 rotates, i.e., the color member 40 rotates, the sliding wheel 60A, which was positioned in the forward position, moves backward along the slope of the first cam surface 44, and the sliding wheel 60B rides up onto the raised portion 42 against the biasing force of the front spring 11 (Figure 23(B)). As a result of the sliding wheel 60B riding up onto the raised portion 42, the color member 40 has moved forward by the height of the raised portion 42 compared to the state shown in Figure 23(A).

[0073] Furthermore, when the rear shaft 3 is rotated, the sliding piece 60B moves circumferentially relative to the raised portion 42, and the sliding piece 60C moves forward along the end face 55 of the rotating cam 50 (Figure 23(C)). Next, the moment the sliding piece 60B passes the end of the raised portion 42, the collar member 40, which had moved forward by the height of the raised portion 42, is instantaneously moved backward by the biasing force of the front spring 11 (Figure 23(D)). At this time, the sliding piece 60B collides with the rear end face of the collar member 40. Simultaneously, the sliding piece 60C collides with the end face of the notch 43 of the collar member 40. Also simultaneously, the sliding piece 60A collides with the front end face 27 of the inner cylinder 20. As a result, the sliding piece 60C is positioned in the notch 43 of the collar member 40, and the switching of the refill 5 is completed (Figure 23(E)). Since these collisions occur almost simultaneously, the user rotating the rear shaft 3 can feel the impact and the resulting clicking sound, and recognize that the switching operation of the retractable refill 5 has been completed. The raised portion 42 may be omitted.

[0074] The torque required to start rotating the rear shaft 3 for switching between the retractable refills 5, i.e., the initial torque, can be changed to a desired value by altering the height of the stepped raised portion 42 and the shape of the stepped portion. By appropriately adjusting the initial torque, taking into account the frictional resistance associated with the movement of the sliding ring 60, it is possible to rotate the refill by applying a torque greater than the initial torque, so that the subsequent inertial force instantaneously switches to the adjacent refill 5.

[0075] Figure 24 is a schematic diagram illustrating the operation of the refill 5 during knocking in another embodiment. Figure 24 is similar to Figure 22, with the upper part being the rear side of the writing instrument 1 and the lower part being the front side of the writing instrument 1. In Figure 24, the axial length of the claw portion 152 of the rotating cam 150 is set so that the front end surface of the claw portion 152 is aligned with the front end surface 27 of the inner cylinder 20. In this case, the refill 5 in the selected position is not the refill 5 connected to the sliding ring 60 located in the advanced position, i.e., the notched portion 43, but rather the refill 5 connected to the sliding ring 60 located in a position opposite the claw portion 152 of the rotating cam 150 in the axial direction. In this embodiment, since the sliding ring 60 and the rotating cam 150 do not come into contact when the rear shaft 3 is rotated, the refill 5 can be switched more smoothly.

[0076] In the embodiment described above, the rotation of the rear shaft 3 relative to the front shaft 2, i.e., the rotation of the rotation selection member, is restricted to a predetermined angle range. That is, as shown in Figure 2, in the writing instrument 1 in a non-writing state, the front end of the guide projection 53 of the rotating cam 50 can be positioned outside the connecting piece 33a of the spacer 30. In other words, the connecting piece 33a of the spacer 30 and the guide projection 53 of the rotating cam 50 do not interfere with each other. In this state, when the rear shaft 3 is rotated to one side relative to the front shaft 2, the rotation restricting piece 33b of the spacer 30 and the guide projection 53 of the rotating cam 50 come into contact, restricting the rotation of the rear shaft 3. That is, one side surface 33c (Figure 10) of the rotation restricting piece 33b of the spacer 30 in the circumferential direction comes into contact with the guide projection 53 of the rotating cam 50. When the rear shaft 3 is rotated in the opposite direction relative to the front shaft 2, the other side surface 33c in the circumferential direction of the rotation restricting piece 33b of the spacer 30 comes into contact with the guide projection 53 of the rotating cam 50. Therefore, the rotation of the rotation selection member can be restricted to a predetermined angle range. In this case, for example, after transitioning from the state shown in Figure 23(A) to the state shown in Figure 23(E) where the sliding piece 60C is positioned in the notch 43 of the collar member 40 by rotating the rear shaft 3 by 120 degrees, the rear shaft 3 cannot be rotated any further. Therefore, in order to position the sliding piece 60B in the notch 43 of the collar member 40, the rear shaft 3 needs to be rotated by 240 degrees in the opposite direction. Alternatively, the rotation of the rotation selection member may be restricted to a predetermined angle range by providing a locking mechanism on the multiple annular projections 37 of the spacer 30 or the multiple annular grooves 14 of the rear shaft 3.

[0077] By restricting the angle in which the rear shaft 3 can rotate to a predetermined range (i.e., a range of 240 degrees), the refill 5 that will protrude due to the knock operation at that moment can be easily identified. That is, in the state shown in Figure 23(A), the clip 28 of the inner cylinder 20 and the mark portion 35 located on the display member 12 are aligned as shown in Figure 1. When the clip 28 and the mark portion 35 are aligned, the refill 5 connected to the sliding ring 60A protrudes when the knock operation is performed. Since the mark portion 35 moves integrally with the front shaft 2, the positional relationship between the clip 28 and the mark portion 35 changes according to the rotation direction of the front shaft 2. Therefore, by looking at the positional relationship between the clip and the mark portion 35, it is possible to determine which refill 5 is in the selected position and will be ready for writing when the knock operation is performed. At this time, the mark portion 35 and the two triangular marks (Figure 1) may be colored with the ink color of the refill 5 to make identification easier.

[0078] The front shaft 2 and the rear shaft 3 can only rotate relative to each other when the writing instrument 1 is not in a writing state. In other words, the rotation selection member can only be rotated when the writing instrument 1 is not in a writing state. That is, when the writing instrument 1 is in a writing state, the rotation cam 50 moves forward as shown in Figure 22(C). At this time, the rotation cam 50 presses the corresponding sliding wheel 60 forward, and the guide projection 53 of the rotation cam 50 is inserted into the groove between the rail portions 32 of the spacer 30. Therefore, even if one tries to rotate the rotation selection member, the rotation is restricted by the locking of the guide projection 53 of the rotation cam 50 and the rail portion 32, and it cannot be rotated. Consequently, when the writing instrument 1 is in a writing state, the front shaft 2 cannot be rotated relative to the rear shaft 3. Thus, malfunctions such as unintentionally rotating the rotation selection member and changing the refill 5 during writing are prevented. On the other hand, when the writing instrument 1 is not in a writing state, the guide projection 53 of the rotating cam 50 is positioned behind the rail portion 32 and does not engage with the rail portion 32, so the rotation selection member can be rotated.

[0079] Furthermore, even if the writing instrument 1 is switched from writing to non-writing by a knock operation, the same refill 5 remains in the selected position unless the rotating selection member is rotated, as explained with reference to Figure 23. Therefore, for example, if you want to write with black ink, then switch to non-writing by knocking, and then write with black ink again, you can put the black refill 5 back into writing mode simply by knocking a single operating part, without having to select an operating part corresponding to each refill. In other words, instead of having to search for a specific operating part from among multiple operating parts to make the desired refill 5 protrude each time, you can easily extend and retract the same refill 5 by knocking a single operating part. On the other hand, switching the refill 5 that is in writing mode by a knock operation can be easily done by rotating the rotating selection member around its axis, as described above.

[0080] Furthermore, since each of the sliding rings 60 moves in the front-to-back direction by rotating the rotating selection member around its axis, there is no need to arrange multiple springs to individually bias each of the refills 5 connected to the sliding rings 60. In other words, a multi-core and retractable writing instrument can be realized with a single front spring 11. As a result, the proportion of the retractable mechanism and refill selection mechanism to the total length in the axial direction of the writing instrument 1 can be reduced, the outer diameter of the writing instrument 1 can be made thinner, and the mechanism can be made simpler. In addition, by arranging the single front spring 11 on the outside of the spacer 30, that is, near the inner circumferential surface of the barrel 4, it is possible to prevent the refill 5 from coming into contact with the front spring 11 and being damaged. That is, since the rail portion 32 of the spacer 30 covers a large portion of the outer circumferential surface of the refill 5 facing radially outward, the refill 5 does not come into contact with the front spring 11. Furthermore, since there are no multiple operating parts arranged on the outer circumferential surface of the writing instrument 1, there are fewer irregularities, and it is possible to print patterns or decorate it.

[0081] To allow determination of which refill 5 is in writing mode by the knocking operation, i.e., which refill 5 is in the selected position, an opening may be provided on the side of the barrel 4, or the barrel 4 may be made transparent or semi-transparent. Specifically, if an opening is provided on the side of the barrel 4, an opening may be formed on the side of the barrel 4 corresponding to each sliding wheel 60 so that it is visible through the opening only when the sliding wheel 60 is in the advanced position. The sliding wheels 60 may be colored the same color as the writing color of the inserted refill 5.

[0082] In the embodiment described above, the writing instrument 1 has three refills 5, but it may have two or four or more, and one of them may be replaced with another type of refill such as a mechanical pencil, marking pen, stylus, eraser, or friction element, making it a dual-function writing instrument. Furthermore, although the writing instrument 1 was provided with an erasing member 7 at its rear end for erasing the writing made by the writing instrument 1, an erasing member may be provided at a different location on the writing instrument 1 in addition to or instead of this. For example, an erasing member may be provided on a part of the front barrel 2, for example, at the front end, or an erasing member may be provided on the clip.

[0083] In the embodiments described above, specific examples such as protrusions, grooves, and cam structures were shown, but they may be composed of different numbers, shapes, or separate parts, as long as they have the same effect.

[0084] In the above-described embodiment, at least one of the refills 5 may be a refill containing thermochromic ink containing a thermochromic colorant. In this case, the writing instrument 1 is a thermochromic writing instrument, and the writing on the writing instrument 1 can be thermochromic due to frictional heat generated when it is rubbed with a friction body acting as an erasing member.

[0085] 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 writing instrument 1 using thermochromic ink, the second color is set to colorless, and the process of heating the line written with the first color (e.g., red) to make it colorless is referred to here as "erasing." Therefore, friction heat is generated by rubbing the writing surface on which the line is written with a friction material, thereby changing the line to colorless, i.e., erasing it. Of course, the second color may be a color other than colorless.

[0086] The thermochromic microcapsule pigments used as thermochromic colorants are not particularly limited and can be used as long as they change color due to heat such as frictional heat, for example, as long as they have the function of changing from colored to colorless, colored to colored, or colorless to colored. Examples include a thermochromic composition containing at least a leuco dye, a developer, and a color change temperature adjuster, which is then microencapsulated.

[0087] The leuco dyes that can be used are not particularly limited, as long as they are electron-donating dyes that function as colorants. Specifically, from the viewpoint of obtaining an ink with excellent color development characteristics, conventionally known dyes such as triphenylmethane-based, spiropyran-based, fluorane-based, diphenylmethane-based, rhodamine lactam-based, indolylphthalide-based, and leucoauramine-based dyes can be used individually (one type) or in combination of two or more types (hereinafter simply referred to as "at least one type").

[0088] 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-methylindole-3-yl)phthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindole-3-yl)- 4-Azaphthalide, 1,3-dimethyl-6-diethylaminofluorane, 2-chloro-3-methyl-6-dimethylaminofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 2-(2-chloroanilino)-6-dibutylaminofluorane, 3,6-dimethoxyfluorane, 3,6- Di-n-butoxyfluorane, 1,2-benz-6-diethylaminofluorane, 1,2-benz-6-dibutylaminofluorane, 1,2-benz-6-ethylisoamylaminofluorane, 2-methyl-6-(Np-tolyl-N-ethylamino)fluorane, 2-(N-phenyl-N-methylamino)-6-(Np-tolyl-N-ethylamino)fluorane, 2-(3'-trifluoromethylanilino)-6-diethylamino Examples include nofluorane, 3-chloro-6-cyclohexylaminofluorane, 2-methyl-6-cyclohexylaminofluorane, 3-di(n-butyl)amino-6-methoxy-7-anilinofluorane, 3,6-bis(diphenylamino)fluorane, methyl-3',6'-bisdiphenylaminofluorane, chloro-3',6'-bisdiphenylaminofluorane, and 3-methoxy-4-dodecoxystylinoquinoline.

[0089] These leuco dyes possess structures such as lactone, pyridine, quinazoline, and bisquinazoline skeletons, and they exhibit color development when these skeletons (rings) open.

[0090] The color developers that can be used are components that have the ability to produce color in the above-mentioned leuco dyes, and examples include phenolic resin compounds, salicylic acid-based metal chlorides, salicylic acid resin-based metal salt compounds, and solid acid compounds.

[0091] Specifically, o-cresol, tert-butylcatechol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-phenylphenol, hexafluorobisphenol, n-butyl p-hydroxybenzoate, n-octyl p-hydroxybenzoate, resorcinol, dodecyl gallate, 2,2-bis(4'-hydroxyphenyl)propane, 4,4-dihydroxydiphenylsulfone, 1,1-bis(4'-hydroxyphenyl)ethane, 2,2-bis(4'-hydroxy-3-methylphenyl)propane, bis(4-hydroxyphenyl)sulfide, 1-phenyl-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 Examples include at least one of the following: 1-bis(4'-hydroxyphenyl)n-dodecane, 2,2-bis(4'-hydroxyphenyl)butane, 2,2-bis(4'-hydroxyphenyl)ethylpropionate, 2,2-bis(4'-hydroxyphenyl)-4-methylpentane, 2,2-bis(4'-hydroxyphenyl)hexafluoropropane, 2,2-bis(4'-hydroxyphenyl)n-heptane, and 2,2-bis(4'-hydroxyphenyl)n-nonane.

[0092] The amount of the color former used may be arbitrarily selected according to the desired color density, and is not particularly limited. Usually, it is preferably selected within the range of about 0.1 to 100 parts by mass with respect to 1 part by mass of the above-mentioned leuco dye.

[0093] The discoloration temperature regulator that can be used is a substance that controls the discoloration temperature in the color development of the above-mentioned leuco dye and color former. Conventionally known discoloration temperature regulators can be used. Specifically, alcohols, esters, ketones, ethers, acid amides, azomethines, fatty acids, hydrocarbons, etc. can be mentioned.

[0094] More specifically, bis(4-hydroxyphenyl)phenylmethane dicaprylate (C7H 15 ), bis(4-hydroxyphenyl)phenylmethane dilaurate (C 11 H 23 ), bis(4-hydroxyphenyl)phenylmethane dimyristate (C 13 H 27 ), bis(4-hydroxyphenyl)phenyl ethane 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)phenyl ethyl hexylidene dimyristate (C 13 H 27 ) and the like can be mentioned.

[0095] The amount of this discoloration temperature regulator used may be appropriately selected according to the desired hysteresis width, color density at the time of color development, etc., and is not particularly limited. Usually, it is preferably used within the range of about 1 to 100 parts by mass with respect to 1 part by mass of the leuco dye.

[0096] Thermochromic microencapsulated pigments can be produced by microencapsulating a thermochromic composition containing at least the above-mentioned leuco dye, developer, and temperature adjustment agent, such that the average particle size is 0.1 to 5 μm. Examples of microencapsulation methods include interfacial polymerization, interfacial polycondensation, insitu polymerization, liquid curing coating, phase separation from aqueous solutions, phase separation from organic solvents, melt-dispersion-cooling, air suspension coating, and spray drying, and can be appropriately selected depending on the application.

[0097] For example, in a phase separation method from an aqueous solution, a leuco dye, a color developer, and a color change 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 such as an amino resin solution or an isocyanate resin solution is gradually added as a capsule membrane agent, and the reaction is continued to prepare the solution. After this dispersion is filtered, the desired thermochromic microcapsule pigment can be produced.

[0098] The content of these leuco dyes, developers, and color change temperature regulators varies depending on the type of leuco dye, developer, and color change temperature regulator used, as well as the microencapsulation method. However, for every 1 unit of dye, the mass ratio is 0.1 to 100 units of developer and 1 to 100 units of color change temperature regulator. In addition, the mass ratio of the capsule membrane to the capsule contents is 0.1 to 1 unit.

[0099] The thermochromic microcapsule pigments can be configured to set the color development temperature (e.g., color development at -20°C or higher) and decolorization temperature (e.g., decolorization at 60°C or higher) of each color to suitable temperatures by appropriately combining the types and amounts of the leuco dye, developer, and color change temperature adjuster mentioned above. Preferably, the pigment changes from colored to colorless due to heat such as frictional heat.

[0100] In thermochromic microcapsule pigments, it is preferable that the wall film be formed of urethane resin, urea / urethane resin, epoxy resin, or amino resin, in order to further improve line density, storage stability, and writing performance. 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 pigment is appropriately determined according to the required wall film strength and line density.

[0101] The average particle size of the thermochromic microcapsule pigment is preferably 0.1 to 5 μm, and more preferably 0.3 to 3 μm, from the standpoint of colorability, color development, ease of decolorization, stability, fluidity in ink, and suppression of adverse effects on writing performance, as well as compatibility with the photochromic microcapsule pigment described later. The "average particle size" defined here is the value obtained by measuring the average particle size (50% diameter) using a particle size analyzer [Microtrac HRA9320-X100 (manufactured by Nikkiso Co., Ltd.)] (refractive index 1.8).

[0102] If the average particle size is less than 0.2 μm, sufficient line density cannot be obtained. On the other hand, if it exceeds 5 μm, it is undesirable because it leads to deterioration of writing performance, a decrease in the dispersion stability of the thermochromic microcapsule pigment, and an increased likelihood of ink backflow due to vibration. Furthermore, the 90% diameter should be 8 μm or less, preferably 6 μm or less. If a certain proportion or more of larger particles are present, the above-mentioned effects tend to become more pronounced. Note that the microcapsule pigment with an average particle size within the above-mentioned range (0.1 to 5 μm) varies depending on the microencapsulation method, but in methods such as phase separation from aqueous solutions, it can be prepared by suitably combining the stirring conditions when producing the microcapsule pigment.

[0103] The specific gravity of the thermochromic microcapsule 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 microcapsule pigment tends to decrease. In addition, microcapsule pigments with a specific gravity exceeding 1.3 are prone to ink backing due to vibration.

[0104] In an aqueous ink composition for writing instruments, in addition to the above-mentioned thermochromic microcapsule pigment, the remainder may include, as appropriate, water as a solvent (tap water, purified water, distilled water, ion-exchanged water, pure water, etc.), and, depending on the application for each writing instrument (for ballpoint pens, marking pens, etc.), water-soluble organic solvents, thickeners, lubricants, rust inhibitors, preservatives, or antibacterial agents, to the extent that the effect is not impaired.

[0105] 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.

[0106] Of these, glycerin is preferably used to suppress ink solidification in the writing area due to ink backing, and the amount added is preferably 1 to 10% by mass of the total ink volume. 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 the dry state.

[0107] As thickeners that can be used, at least one selected from the group consisting of synthetic polymers, cellulose, and polysaccharides is preferred. Specifically, examples include gum arabic, tragacanth gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, xanthan gum, gelan gum, succinoglycan, dieutan 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 hydroxide, 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, and the like.

[0108] Of these, polysaccharides are preferred. Due to their rheological properties, polysaccharides tend to be less affected by vibrations in terms of fluidity, and problems such as poor writing due to ink backflow are less likely to occur. Xanthan gum, in particular, is preferred because it has an excellent balance with other properties required for writing instrument inks.

[0109] Lubricants include fatty acid esters of polyhydric alcohols, which are also used as surface treatment agents for pigments; higher fatty acid esters of sugars; higher polyoxyalkylene fatty acid esters; alkyl phosphate esters; alkyl sulfonates of higher fatty acid amides; alkyl allyl sulfonates; derivatives of polyalkylene glycols; fluorinated surfactants; and polyether-modified silicones. Rust inhibitors include benzotriazole, tolyltriazole, dicyclohexylammonium nitride, and saponins. Preservatives or antibacterial agents include phenol, sodium omazine, sodium benzoate, and benzimidazole compounds.

[0110] Conventional methods can be used to produce this aqueous ink composition for writing instruments. For example, it can be obtained by blending predetermined amounts of the above-mentioned thermochromic and photochromic microcapsule pigments, as well as each component in the aqueous solution, and stirring and mixing them using a stirrer such as a homomixer or disper. Furthermore, if necessary, coarse particles in the ink composition may be removed by filtration or centrifugation.

[0111] The viscosity 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 with excellent writing properties and long-term stability can be obtained. Furthermore, S=αD n (However, 1>n>0) (S is shear stress (dyn / cm) 2 ), D is the shear rate (s -1 It is preferable that the non-Newtonian viscosity index n, which can be determined by the viscosity formula (where α is the non-Newtonian viscosity coefficient), is between 0.2 and 0.6. By setting the non-Newtonian viscosity index n within the above range in addition to the viscosity range, it becomes possible to appropriately set the fluidity of the ink in response to vibration, thereby preventing ink backflow.

[0112] The surface tension of the water-based 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 ink backflow.

[0113] Within the refill, an ink follower may be placed immediately behind the ink. The materials constituting the follower can consist of at least a non-volatile or low-volatile organic solvent and a thickener. The non-volatile or low-volatile organic solvent used in the ink follower is used as the base oil of the ink follower, and for example, liquid paraffin can be used. Mineral oil and chemically synthesized oil can be used as liquid paraffin, and as chemically synthesized oil, polybutene, poly-α-olefin, ethylene-α-olefin oligomer, etc. can be used.

[0114] 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.).

[0115] 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, Polybutene 0N (all manufactured by Nippon Oil & Fats Co., Ltd.), Polybutene HV-15 (manufactured by Nippon Petrochemical Co., Ltd.), and 35R (manufactured by Idemitsu Kosan Co., Ltd.).

[0116] Specific examples of poly-α-olefins that can be used include, for example, 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.).

[0117] Specific ethylene α-olefin oligomers that can be used include, for example, commercially available products such as Lucant HC-10, HC-20, HC-100, HC-150, (HC-600, HC-2000) (all manufactured by Mitsui Chemicals, Inc.).

[0118] These non-volatile or low-volatility organic solvents can be used individually or in combination of two or more.

[0119] Examples of thickeners used in ink-following bodies include calcium salts of phosphate esters, fine silica particles, polystyrene-polyethylene / butylene rubber-polystyrene block copolymers, polystyrene-polyethylene / propylene rubber-polystyrene block copolymers, hydrogenated styrene-butadiene rubber, styrene-ethylenebutylene-olefin crystal block copolymers, olefin crystal-ethylenebutylene-olefin crystal block copolymers, and acetalkoxyaluminum diarylates. One or more of these can be used.

[0120] Preferred commercially available calcium salts of phosphate esters that can be used include CrodaxDP-301LA (manufactured by Croda Japan Co., Ltd.). The fine silica particles that can be used include hydrophilic fine silica particles and hydrophobic fine silica particles. Preferred commercially available hydrophilic silica particles include AEROSIL-300 and AEROSIL-380 (manufactured by Nippon Aerosil Co., Ltd.), while preferred commercially available hydrophobic silica particles include AEROSIL-974D and AEROSIL-972 (manufactured by Nippon Aerosil Co., Ltd.).

[0121] Furthermore, preferred commercially available polystyrene-polyethylene / butylene rubber-polystyrene block copolymers include Kraton GFG-1901X, Kraton GG-1650 (both manufactured by Shell Japan), Septon 8007, and Septon 8004 (both manufactured by Kuraray). In addition, preferred 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).

[0122] Preferred commercially available hydrogenated styrene-butadiene rubbers include DYNARON1320P, DYNARON1321P (both manufactured by JSR Corporation), ToughTec Hl041, and ToughTec Hl141 (both manufactured by Asahi Kasei Corporation).

[0123] Preferred commercially available products of styrene-ethylenebutylene-olefin crystal block copolymer include DYNARON4600P (manufactured by JSR Corporation), and preferred commercially available products of olefin crystal-ethylenebutylene-olefin crystal block copolymer include DYNARON6200P and DYNARON6201B (manufactured by JSR Corporation).

[0124] A preferred commercially available acetalkoxyaluminum diarylate is PlenAct AL-M (manufactured by Ajinomoto Fine Techno Co., Ltd.).

[0125] Among these thickeners, the use of thermoplastic olefin elastomers such as styrene-ethylenebutylene-olefin crystalline block copolymers and olefin crystalline-ethylenebutylene-olefin crystalline block copolymers is preferred in order to further exhibit the effects of the present invention.

[0126] Furthermore, in order to obtain an ink-following body that prevents ink back, it is preferable that the average value of the tanδ measured for each frequency while exponentially increasing in the frequency range of 1 to 63 rad / s be 1.0 or higher, and more preferably 1.7 to 3.4.

[0127] Here, tanδ is a value that represents the loss modulus of elasticity / storage modulus of elasticity. Conventionally, it was known that it was preferable for the average value of the tanδ measured for each frequency while exponentially increasing in the frequency range "1 to 63 rad / s" to be 1.0 or less. In the present invention, by making the average value of the tanδ measured for each frequency in the above range of 1 to 63 rad / s 1.0 or more, it is possible to absorb vibrations and prevent inkback.

[0128] As the material for forming the friction body, rubber elastic materials such as thermosetting rubbers like silicone rubber, nitrile rubber, ethylene propylene rubber, and ethylene propylene diene rubber, and thermoplastic elastomers such as styrene elastomers, olefin elastomers, polyester elastomers, and urethane elastomers, as well as mixtures of two or more rubber elastic materials, and mixtures of rubber elastic materials and synthetic resins can be used. The friction body is formed by configuring these materials so that the amount of Taber wear on the CS-17 wear wheel of the Taber wear tester is less than 25 mg under a load of 9.8 N and a 1000 rpm environment in the abrasion test (ASTM D1044) specified in JIS K7204.

[0129] Furthermore, alkylsulfonate phenyl esters and cyclohexanedicarboxylic acid esters may be added to the friction material. The inclusion of alkylsulfonate phenyl esters and cyclohexanedicarboxylic acid esters in the friction material allows for the erasure of handwriting without damaging the paper surface or blurring printed characters. In addition, the friction material preferably has a durometer A hardness of 60 or higher as specified in JIS K6203. This ensures the required hardness and enables more stable rubbing action. The friction material can also be used as a touch pen or stylus pen, and conductivity may be added.

[0130] Furthermore, it is preferable that the friction element is colored with a color whose lightness value is lower than that of the thermochromic ink contained in the writing instrument 1. That is, when the thermochromic ink of the writing instrument 1 is transferred to the surface of the friction element without discoloration during use, the transfer of the thermochromic ink can be made less noticeable. In particular, by making the color of the friction element black or having a lightness value of 2.5 or less, surface staining associated with the use of the friction element can also be made less noticeable.

[0131] Lightness values ​​are determined using the Munsell color system with measuring devices such as a general-purpose colorimeter (TC-8600A, manufactured by Tokyo Denshoku Co., Ltd.). The lightness value of the friction material is measured on the surface, and the lightness value of the thermochromic ink is determined by measuring the ink on a line written on paper (old JIS P3201; high-quality paper made from 100% chemical pulp, basis weight range 40-157 g / m2, whiteness 75.0% or higher) at a writing speed of 4.5 m / min and a pitch interval of 0.1 mm.

[0132] Furthermore, in the above-described embodiment, at least one of the multiple refills 5 may be a refill containing mechanical pencil lead, pencil lead, or eraser-erasable ink, and at least one of the remaining refills 5 may be a refill containing thermochromic ink. In this case, by using a plastic eraser or eraser as the erasing member 7, the writing made with mechanical pencil lead, pencil lead, or eraser-erasable ink can be erased. In addition, the writing made with thermochromic ink can be rubbed with a plastic eraser or eraser to generate frictional heat and cause the writing to change color due to heat.

[0133] Therefore, plastic erasers or rubber erasers can be used as erasing materials for different types of writing, namely, as erasing materials for erasing writing made with mechanical pencil lead, pencil lead, or eraser-erasable ink, and as friction materials for heat-changing (erasing) writing made with heat-changeable ink. Here, "being able to erase writing with a plastic eraser or rubber eraser" means that the writing can be erased by rubbing it with the plastic eraser or rubber eraser without staining the surrounding paper or other surfaces.

[0134] The lead of a mechanical pencil or pencil preferably contains, for example, 3 to 80% by weight of the total amount of glass powder, which is in the form of flakes with an average thickness of 0.1 to 2 μm, an aspect ratio of 5 to 150, and a flatness of 200 nm or less, or granular glass powder with an average particle size of 0.1 to 50 μm and a sphericity of 0.1 to 50 μm, dispersed or encapsulated in the compounding composition before firing, selected from inorganic pigments, organic pigments, and dyes (excluding glass powder).

[0135] The eraserable ink preferably contains at least 5 to 30% by weight of colored resin particles, which have an average particle diameter of 2 to 20 μm and are non-thermoplastic, relative to the total amount of the ink composition, and uncolored particles, which have a glass transition temperature of less than 0°C. The "average particle diameter" defined herein is the value obtained by measuring the average particle diameter (50% diameter) (refractive index 1.8) using a particle size analyzer [Microtrac HRA9320-X100 (manufactured by Nikkiso Co., Ltd.)] as described above.

[0136] In this case, the friction body is preferably composed of an acrylic thermoplastic resin powder with a primary particle size of 20-80 μm, a plasticizer, and an inorganic powder, in addition to the aforementioned friction body, and the thermoplastic resin is polyvinyl chloride resin or a copolymer thereof, and the inorganic powder is calcium carbonate and / or magnesium carbonate, because it can act on both the markings of thermochromic ink and erasable ink by rubbing. Note that "glass transition temperature (Tg)" refers to the temperature at which the mobility of the amorphous portion of the acrylic resin powder increases and it becomes rubbery.

[0137] Figure 25 is a perspective view of a writing instrument 201 according to another embodiment of the present invention. Compared to the writing instrument 1 according to the above-described embodiment, the writing instrument 201 differs in the shape of the rear shaft and spacer, but other components are the same or substantially the same; therefore, only the differences will be described.

[0138] Figure 26 is a longitudinal cross-sectional view of the rear shaft 203. In the assembled state of the writing instrument 1, the rear shaft 203 is positioned such that its upper side is the rear side of the writing instrument 201 in Figure 26. Two elongated projections 213, roughly I-shaped, are provided on the inner circumferential surface of the rear shaft 203 as locking parts. The two elongated projections 213 are spaced 120 degrees apart around the central axis. Note that the elongated projections 213 may be provided as separate components, for example, rather than on the inner circumferential surface of the rear shaft 203. The position of the front end of the elongated projection 213 on the rear shaft 203 is the same as the position of the front end of the T-shaped projection 13 on the rear shaft 3 of the corresponding writing instrument 1. However, the position of the rear end of the elongated projection 213 on the rear shaft 203 is located forward of the position of the rear end of the T-shaped projection 13 on the rear shaft 3 of the writing instrument 1. That is, the axial length of the elongated projection 213 is shorter than the axial length of the T-shaped projection 13.

[0139] Figure 27 is a perspective view of the spacer 230. In the assembled state of the writing instrument 201, the spacer 230 is positioned such that its upper side is at the rear of the writing instrument 201 in Figure 27. The spacer 230 has a connecting portion 233 formed to connect the rear ends of the three rail portions 32. The connecting portion 233 has three connecting piece 33a with an outer shape formed to be slightly smaller in diameter than the outer diameter of the three rail portions 32. That is, the spacer 230 does not have a rotation restricting piece 33b like the spacer 30 of the writing instrument 1. Therefore, in the writing instrument 201, the rear shaft 203 can rotate freely relative to the front shaft 2. That is, the rotation of the rear shaft 203 around its axis is not restricted by contact between the connecting portion 233 of the spacer 230 and the guide projection 53 of the rotating cam 50. A projection-shaped mark portion 235 extending forward is formed on the front end surface of the flange portion 34. The mark portion 235 protrudes radially outward more than the mark portion 35 in the writing instrument 1. Therefore, in the writing instrument 201, the mark portion 235 protrudes from the outer surface of the barrel 4 to a degree that it can be clearly identified by touch (Figure 25). This makes it easy to identify the connection between the front barrel 2 and the rear barrel 3.

[0140] Figure 28 is a schematic diagram illustrating the movement of the refill during the knocking operation. The movement of the refill in writing instrument 201 during the knocking operation is basically the same as the movement of the refill in writing instrument 1 during the knocking operation, as described above with reference to Figure 22. However, unlike the T-shaped projection 13 in writing instrument 1, the elongated projection 213 in writing instrument 201 is not related to the movement of the refill during the knocking operation, and is therefore not shown in Figure 28. In writing instrument 1, as explained with reference to Figure 22, two of the three sliding wheels 60 were locked to the T-shaped projection 13, restricting the forward movement of the two sliding wheels 60. However, in writing instrument 201, the position of the rear end of the elongated projection 213 is located in front of the position of the rear end of the T-shaped projection 13 in writing instrument 1, so the sliding wheels 60 do not lock onto the elongated projection 213.

[0141] In this case, in the writing instrument 1, the sliding wheel 60 is engaged or partially engaged with the T-shaped projection 13 in both the non-writing state (Figure 22(A)) and the writing state (Figure 22(C)). Therefore, if the writing instrument 1 is accidentally dropped with its front end facing downwards, a strong axial impact is applied to the sliding wheel 60 and the refill 5 connected to the sliding wheel 60. At this time, since the sliding wheel 60 is engaged with the T-shaped projection 13, the refill 5 is subjected to an inertial force that causes it to detach from the sliding wheel 60.

[0142] In contrast, in the writing instrument 201, the sliding wheel 60 does not engage with the elongated projection 213, so even if the front end of the writing instrument 201 falls downwards, the refill 5 moves forward together with the sliding wheel 60. Therefore, there is no risk of the refill 5 coming off the sliding wheel 60. In other words, in the writing state of the writing instrument 201, the sliding wheel 60 and the first cam surface 44 are separated, so the forward movement of only the sliding wheel 60 is not restricted, and there is no risk of the refill 5 coming off the sliding wheel 60. The forward movement of the refill 5 and the sliding wheel 60 is restricted by the writing portion 5a of the refill 5 contacting the tapered portion at the front end of the front shaft 2. [Explanation of symbols]

[0143] 1 writing implements 4 shaft cylinder 5 Refills 7. Erasing member 10 Rear spring 11 Front spring 13 T-shaped protrusion 20 Inner cylinder 30 Spacers 40 Color components 50 rotation cam 60 sliding sprockets 70 Operating member 80 rotors 90 Brake rod 100 knock rings

Claims

[Claim 1] A writing instrument comprising a barrel, a writing element disposed within the barrel and having a writing section, and an eraser capable of erasing the writing made by the writing element, The device further comprises a brake member that can move in the front-rear direction within the shaft cylinder, a rotating member that moves together with the eraser and can rotate about a central axis, and a locking part that can lock with the rotating member. A writing instrument characterized in that a projection is provided on the inner surface of the rotating member, and the brake member inserted into the rotating member engages with the projection, thereby restricting the rotation of the rotating member and preventing the rotating member from moving forward by engaging with the locking portion.

Images