Writing implement

Abstract

This writing implement (10) comprises: a shaft tube (15); a tip member (50) having a writing part (52) for forming handwriting; and a holding member (70) that is attached to the shaft tube (15) and holds the tip member (50). The holding member (70) has a plurality of ribs (71) that protrude inward and come into contact with the tip member (50), and a plurality of claw parts (80) that extend to the rear and are disposed outside the tip member (50). In a state in which the holding member (70) is attached to the shaft tube (15), the claw parts (80) deform inward and come into contact with the tip member (50), thereby restricting movement of the tip member (50) in an axial direction (da) with respect to the holding member (70).

Description

writing implements

[0001] The present invention relates to a writing instrument.

[0002] Conventionally, writing instruments such as marking pens having a tip member formed of a fiber tip or the like have been known. In such writing instruments, the tip member is fixed to the barrel via a holding member or the like. This prevents the pen tip from sinking into the barrel due to writing pressure when a user grips the barrel and writes, which would hinder writing.

[0003] As a method for fixing a tip member to a holding member or a barrel, a technique is known in which ribs are provided on the inner surface of the holding member or barrel to press-fit and fix the tip member. JP2019-155879A describes a writing instrument equipped with a holding member that holds a tip member, in which multiple ribs are formed on the inner surface of the rear end of the holding member and the tip member is press-fitted into these ribs.

[0004] Another known method for fixing a tip member to a holding member or barrel is to insert a pin radially into the tip member and fix the pin to the holding member or barrel. JPH6-7987U describes a writing instrument that includes a holder for holding a tip member, and the tip member and holder are fixed together by a pin inserted from the outer periphery of the holder.

[0005] While the technology of providing ribs on the inner surface of the retaining member or barrel allows the tip member to be fixed while suppressing an increase in the number of parts, it requires the tip member to be significantly deformed in order to be firmly fixed. Because the tip member is made of fiber chips or the like, significantly deforming the tip member may cause the deformed portion to collapse, which may impede the flow of ink in this area.

[0006] Furthermore, while the technique of inserting a pin into the tip member allows the tip member to be firmly fixed to the holding member or barrel, it increases the number of parts. Furthermore, an additional step of inserting the pin is required to fix the tip member to the holding member or barrel. Therefore, there is a risk that the manufacturing cost of the writing instrument will increase.

[0007] The present invention has been made in consideration of the above points, and has as its object to provide a writing implement that can more firmly fix a tip member with a simple structure.

[0008] The writing instrument of the present invention comprises: [1] a barrel; a tip member having a writing portion for forming handwriting; and a holding member attached to the barrel and holding the tip member, wherein the holding member has a plurality of ribs that protrude inward and contact the tip member, and a plurality of claw portions that extend rearward and are positioned on the outside of the tip member, and when the holding member is attached to the barrel, the claw portions deform inward and contact the tip member, thereby restricting axial movement of the tip member relative to the holding member.

[0009] The writing instrument of the present invention is [2] the writing instrument according to [1], wherein the rib extends linearly in the axial direction.

[0010] The writing instrument of the present invention is [3] the writing instrument according to [1] or [2], which has three or more of the claw portions.

[0011] The writing instrument of the present invention is a writing instrument described in any one of [1] to [3], [4] comprising a barrel-side inclined surface provided on the inner surface of the barrel, extending inward as it approaches the rear, and / or a claw-side inclined surface provided on the outer surface of the claw portion, extending inward as it approaches the rear.

[0012] The writing instrument of the present invention is [5] the writing instrument according to any one of [1] to [4], which is provided with a protrusion formed on the outer surface of the nail portion.

[0013] The writing instrument of the present invention is a writing instrument described in any one of [1] to [5], [6] comprising an inner inclined surface provided on the inner surface of the claw portion, which extends outward as it moves rearward when the holding member is not attached to the barrel.

[0014] The writing instrument of the present invention is a writing instrument described in any one of [1] to [6], which is provided with a locking portion provided on the outer surface of the holding member and a lockable portion provided on the inner surface of the barrel, and in which, when the holding member is attached to the barrel, the locking portion locks with the lockable portion.

[0015] The writing instrument of the present invention is [8] the writing instrument according to [7], wherein the locking portion is located forward of the claw portion.

[0016] The writing instrument of the present invention is a writing instrument as described in [9] or [8], wherein when the holding member is attached to the barrel from the front, the claw portion restricts the axial movement of the tip member relative to the holding member, and then the locking portion locks into the locked portion.

[0017] The writing instrument of the present invention is a writing instrument according to any one of [1] to [9], wherein

[10] the minimum distance between two circumferentially adjacent claw portions is smaller than the maximum radial thickness of the claw portions.

[0018] The writing instrument of the present invention is a writing instrument according to any one of [1] to

[10] , wherein

[11] the minimum distance between two adjacent claw portions in the circumferential direction is smaller than the minimum radial thickness of the claw portions.

[0019] The writing instrument of the present invention is the writing instrument described in

[10] or

[11] , wherein

[12] the holding member has a bulge portion that reduces the distance between two adjacent claw portions in the circumferential direction.

[0020] The writing instrument of the present invention is a writing instrument described in any one of [1] to

[12] ,

[13] wherein the holding member has a main body portion and the claw portion extending from the main body portion, the holding member has a thick portion formed in the main body portion, and the radial thickness of the thick portion is greater than the minimum distance between two circumferentially adjacent claw portions.

[0021] The writing instrument of the present invention is the writing instrument described in

[13] ,

[14] in which the rib constitutes the thick portion, and when the holding member is viewed from the radial direction, the rib is arranged in axial alignment with the gap formed between two adjacent claw portions.

[0022] According to the present invention, it is possible to provide a writing instrument that can more firmly fix a tip member with a simple configuration.

[0023] FIG. 1 is a diagram showing one embodiment of the present invention, and is an external view showing an example of a writing instrument. FIG. 2 is a longitudinal cross-sectional view of the writing instrument of FIG. 1. FIG. 3 is a front view of the writing instrument of FIG. 1. FIG. 4 is a perspective view showing a holding member of the writing instrument. FIG. 5 is a half-split perspective view showing the holding member. FIG. 6A is a diagram for explaining an example of a process for attaching a tip member and a holding member to a barrel, and is a longitudinal cross-sectional view corresponding to line A-A in FIG. 3. FIG. 6B is a diagram for explaining an example of a process for attaching a tip member and a holding member to a barrel, and is a longitudinal cross-sectional view corresponding to line B-B in FIG. 3. FIG. 7A is a diagram for explaining an example of a process for attaching a tip member and a holding member to a barrel, and is a longitudinal cross-sectional view corresponding to line A-A in FIG. 3. FIG. 7B is an enlarged view of the portion marked 7B in FIG. 7A. FIG. 7C is a diagram for explaining an example of a process for attaching a tip member and a holding member to a barrel, and is a longitudinal cross-sectional view corresponding to line B-B in FIG. 3. FIG. 7D is an enlarged view of the portion marked 7D in FIG. 7C. FIG. 8A is a diagram illustrating an example of a process for attaching a tip member and a retaining member to a barrel, and is a longitudinal cross-sectional view corresponding to line A-A in FIG. 3. FIG. 8B is an enlarged view of a portion marked 8B in FIG. 8A. FIG. 8C is a diagram illustrating an example of a process for attaching a tip member and a retaining member to a barrel, and is a longitudinal cross-sectional view corresponding to line B-B in FIG. 3. FIG. 8D is an enlarged view of a portion marked 8D in FIG. 8C. FIG. 9A is a diagram illustrating an example of a process for attaching a tip member and a retaining member to a barrel, and is a longitudinal cross-sectional view corresponding to line A-A in FIG. 3. FIG. 9B is an enlarged view of a portion marked 9B in FIG. 9A. FIG. 9C is a diagram illustrating an example of a process for attaching a tip member and a retaining member to a barrel, and is a longitudinal cross-sectional view corresponding to line B-B in FIG. 3. FIG. 9D is an enlarged view of a portion marked 9D in FIG. 9C. FIG. 10 is a perspective view showing a modified retaining member. FIG. 11 is a side view showing the retaining member of FIG. 10. Fig. 12 is a view showing the claw portion of the holding member of Fig. 10 as viewed from the tip end side. Fig. 13 is a half-split perspective view showing the holding member of Fig. 10. Fig. 14 is a vertical cross-sectional view showing the holding member of Fig. 10. Fig. 15 is a cross-sectional view corresponding to line XV-XV in Fig. 11. Fig. 16 is a perspective view showing another modified example of the holding member.FIG. 17 is a side view showing the holding member of FIG. 16. FIG. 18 is a perspective view showing yet another modified example of the holding member. FIG. 19 is a side view showing the holding member of FIG. 18. FIG. 20 is a perspective view showing yet another modified example of the holding member. FIG. 21 is a side view showing the holding member of FIG. 20. FIG. 22 is a perspective view showing yet another modified example of the holding member. FIG. 23 is a side view showing the holding member of FIG. 22. FIG. 24 is a side view showing an example of how the claw portions of the holding member entangle. FIG. 25 is a perspective view showing an example of how the claw portions of the holding member entangle. FIG. 26 is a side view showing another example of how the claw portions of the holding member entangle. FIG. 27 is a perspective view showing another example of how the claw portions of the holding member entangle. FIG. 28 is a view showing a modified example of a writing instrument, and is an external view showing an example of a writing instrument having a friction body. FIG. 29 is a view showing a modified example of a friction body. FIG. 30 is a view showing another modified example of a friction body. FIG. 31 is a view showing yet another modified example of a friction body. Fig. 32 is a front view of the friction body of Fig. 31. Fig. 33 is a perspective view showing a modified example of the tip member and the support portion.

[0024] An embodiment of the present invention will now be described with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of ease of illustration and understanding.

[0025] Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," and "identical," as well as values ​​of lengths and angles, are not to be construed as being bound by strict meanings, but rather as including a range within which similar functions can be expected.

[0026] In this specification, the direction in which the central axis A of the writing instrument 10 extends (longitudinal direction, up-down direction in a longitudinal cross section) is referred to as the axial direction da, the direction perpendicular to the axial direction da is referred to as the radial direction, and the direction along the circumference around the central axis A is referred to as the circumferential direction. Along the axial direction da, the side that approaches a writing surface such as a piece of paper when writing (the upper side in a longitudinal cross section) is referred to as the front, and the side that moves away from the writing surface (the lower side in a longitudinal cross section) is referred to as the rear. Along the radial direction, the side that approaches the central axis A is referred to as the inside or inner side, and the side that moves away from the central axis A is referred to as the outside or outer side.

[0027] Fig. 1 is a diagram showing one embodiment of the present invention, and is an external view showing an example of a writing instrument 10. Fig. 2 is a longitudinal cross-sectional view of the writing instrument 10. Fig. 3 is a view of the writing instrument 10 as seen from the front. Fig. 4 is a perspective view showing a holding member 70 of the writing instrument 10. Fig. 5 is a half-cut perspective view showing the holding member 70. In particular, Fig. 5 shows the holding member 70 cut along a plane including the central axis A of the writing instrument 10.

[0028] The writing instrument 10 of this embodiment is, for example, a marking pen (marker), a felt-tip pen, etc. In this embodiment, an example will be described in which the writing instrument 10 is a marking pen. The writing instrument 10 includes an ink reservoir 11, a barrel 15, a tip member 50, and a holding member 70.

[0029] The barrel 15 extends in the axial direction da along the central axis A of the writing instrument 10. Therefore, the central axis of the barrel 15 coincides with the central axis A of the writing instrument 10. The barrel 15 includes a front barrel 20 and a rear barrel 40 attached to the rear end of the front barrel 20.

[0030] Front barrel 20 is a member that forms the front portion of writing instrument 10. Front barrel 20 has a generally cylindrical shape. The central axis of front barrel 20 coincides with central axis A of writing instrument 10. Rear barrel 40 is a member that forms the rear portion of writing instrument 10. Rear barrel 40 has a generally cylindrical shape. The central axis of rear barrel 40 coincides with central axis A of writing instrument 10. In this embodiment, rear barrel 40 is intended to be grasped with the fingers of a user when writing with writing instrument 10. Rear barrel 40 may include an inner barrel and a grip portion disposed on the outside of the inner barrel. The grip portion is a portion that is held with the fingers of a user when writing with writing instrument 10. However, this is not limited thereto, and writing instrument 10 may also be configured so that the user grasps front barrel 20 to write. In this embodiment, the front barrel 20 is attached to rear barrel 40 by inserting the rear end portion of front barrel 20 into the front end portion of rear barrel 40. For example, front axle 20 may be attached to rear axle 40 by press-fitting the rear end of front axle 20 into the front end of rear axle 40. Alternatively, front axle 20 may be attached to rear axle 40 by a front-axle-side convex portion formed on the outer circumferential surface of the rear end of front axle 20 climbing over a rear-axle-side convex portion formed on the inner circumferential surface of the front end of rear axle 40 and becoming engaged with said rear-axle-side convex portion. A flange 21 is formed on the outer circumferential surface of front axle 20. With front axle 20 attached to rear axle 40, flange 21 may come into contact with the front end of rear axle 40. A front cap 16 that covers tip member 50 and prevents ink from drying out on tip member 50 may be attached to front axle 20 or retaining member 70 (see FIG. 29 ).

[0031] A groove 23, a pressing surface 27, and a locked portion 29 are formed on the inner surface of the front axle 20. The groove 23 is a groove that receives an outer rib 72 and a protrusion 82 (described later) of the retaining member 70 when the retaining member 70 is attached to the front axle 20. The groove 23 is formed to be recessed radially outward from the inner peripheral surface of the front axle 20. Each groove 23 extends linearly along the axial direction da. The multiple grooves 23 may be arranged at equal angular intervals relative to one another in the circumferential direction. In the present embodiment, the front axle 20 has four grooves 23. The four grooves 23 are arranged at angular intervals of 90 degrees relative to one another. This is not a limitation, and the front axle 20 may have two, three, five, or more grooves 23. A barrel-side inclined surface 25 is formed at the rear end of each groove 23. The barrel-side inclined surface 25 is a surface that extends inward as it extends rearward. The barrel-side inclined surface 25 has the function of guiding the claw portion 80 (the protrusion 82 ) inward when the holding member 70 is attached to the front barrel 20 .

[0032] Pressing surface 27 is a part of the inner circumferential surface of front body 20 and has a generally cylindrical shape. Pressing surface 27 has the function of pressing claw portion 80 (protrusion 82) inward after holding member 70 is attached to front body 20.

[0033] Locked portion 29 is a portion with which a locking portion 74 (described later) of retaining member 70 locks when retaining member 70 is attached to front body 20. Locked portion 29 may be, for example, a convex portion or a concave portion formed on the inner circumferential surface of front body 20. In the present embodiment, locked portion 29 is an annular convex portion formed on the inner circumferential surface of front body 20 and extending in the circumferential direction.

[0034] The ink reservoir 11 is a component that stores ink for forming handwriting. The ink reservoir 11 has a substantially cylindrical shape. The ink reservoir 11 is disposed within the barrel 15. The central axis of the ink reservoir 11 coincides with the central axis A of the writing instrument 10. The ink reservoir 11 may be, for example, a component having continuous pores that can be impregnated with and store ink. Such an ink reservoir 11 may be, for example, a heat-fused fiber bundle, a resin-processed fiber bundle, a resin-processed felt, a needle-punched felt, a porous body such as a sponge, or the like. The ink reservoir 11 may also have an outer periphery formed of a synthetic resin film or the like.

[0035] The tip member (first tip member) 50 is a member that forms handwriting on a writing surface such as paper. The tip member 50 is made of a material that allows ink to flow through it in the axial direction da. For example, the tip member 50 may be made of a porous body having open cells. Alternatively, the tip member 50 may be made of a fiber bundle, a bristle bundle, felt, a resin having capillary passages extending in the axial direction da, or the like. The tip member 50 may also be made of a porous body of synthetic resin having open cells.

[0036] The tip member 50 has a writing portion 52, an intermediate portion 54, and a rear end portion 56. The writing portion 52 is the portion that forms handwriting on the writing surface. At least a portion of the front of the writing portion 52 protrudes forward from the holding member 70. The writing portion 52 may have, for example, a chisel shape. However, the writing portion 52 is not limited to this, and may have other shapes such as a bullet shape, a rectangular shape, a square prism shape, or a plate shape. The writing portion 52 may have flexibility that allows it to bend and deform in a direction perpendicular to the longitudinal direction in a cross section (the horizontal direction, the left-right direction in FIG. 3 ) due to writing pressure.

[0037] The intermediate portion 54 is located rearward of the writing portion 52 and has a generally cylindrical shape. At least a portion of the intermediate portion 54 contacts an inner rib 71 (described below) of the holding member 70. The rear end portion 56 is located rearward of the intermediate portion 54. The rear end portion 56 has a shape whose cross-sectional area decreases toward the rear. The rear end portion 56 may have, for example, a conical shape, a pyramidal shape, a truncated conical shape, a truncated pyramidal shape, or the like. In this embodiment, the rear end portion 56 has a truncated conical shape whose cross-sectional area decreases toward the rear. The rear end portion 56 is inserted into the ink reservoir 11 from the front of the ink reservoir 11. Ink can flow from the ink reservoir 11 through the rear end portion 56 and the intermediate portion 54 toward the writing portion 52.

[0038] Writing instrument 10 may further include a second tip member 12 and a rear cap 13. Second tip member 12 may be configured to be able to produce handwriting different from that produced by writing portion 52 of tip member 50. The rear end of second tip member 12 protrudes rearward from the rear end of rear barrel 40 and constitutes the writing portion that produces handwriting. The front end of second tip member 12 is inserted into ink reservoir 11 from the rear of ink reservoir 11. Ink can flow from ink reservoir 11 through second tip member 12 toward the rear end of second tip member 12. Rear cap 13 is detachably attached to the rear end of rear barrel 40. Rear cap 13 covers second tip member 12 to prevent ink from drying out in second tip member 12.

[0039] The retaining member 70 is a member that holds the tip member 50. The retaining member 70 is attached to the front end of the barrel 15. In particular, in the example shown in FIGS. 1 and 2, the retaining member 70 is attached to the front end of the front barrel 20. The retaining member 70 has a generally cylindrical shape. The central axis of the retaining member 70 coincides with the central axis A of the writing instrument 10. The retaining member 70 is formed, for example, by injection molding of a synthetic resin. Examples of synthetic resins that can be used to form the retaining member 70 include polypropylene, polycarbonate, polyethylene, polyacetal, polyethylene terephthalate, elastomer, and acrylonitrile-butadiene-styrene (ABS) resin. The retaining member 70 includes a plurality of inner ribs (ribs) 71 and a plurality of claw portions 80. The retaining member 70 may also include an outer rib 72, a locking portion 74, a flange portion 75, a ventilation groove 77, and a support portion 78.

[0040] The inner rib 71 has the function of contacting the intermediate portion 54 of the tip member 50 when the tip member 50 is inserted into the holding member 70, thereby temporarily fixing the tip member 50 to the holding member 70. The inner rib 71 is formed to protrude radially inward from the inner peripheral surface of the holding member 70. As shown in FIG. 5 , each inner rib 71 extends linearly along the axial direction da. The multiple inner ribs 71 may be arranged at equal angular intervals relative to each other in the circumferential direction. In this embodiment, the holding member 70 has four inner ribs 71. The four inner ribs 71 are arranged at angular intervals of 90 degrees relative to each other. However, the number of inner ribs 71 is not limited to this, and the holding member 70 may have two, three, five or more inner ribs 71.

[0041] The diameter of a circle inscribed in the inner ends of the multiple inner ribs 71 is smaller than the diameter of the intermediate portion 54. In this embodiment, the distance between the inner ends of two inner ribs 71 facing each other across the central axis A is smaller than the diameter of the intermediate portion 54. In this embodiment, when attaching the tip member 50 to the holding member 70, the tip member 50 is inserted into the holding member 70 from the rear. The writing part 52 passes through the area of ​​the holding member 70 where the inner ribs 71 are formed and protrudes forward. Then, the intermediate portion 54 of the tip member 50 is pressed into the area of ​​the holding member 70 where the inner ribs 71 are formed. As a result, the outer peripheral surface of the tip member 50 (intermediate portion 54) is pressed against the inner ribs 71 and deforms inward. At this time, frictional force is generated between the outer peripheral surface of the tip member 50 (intermediate portion 54) and the inner rib 71. Therefore, movement of the tip member 50 in the axial direction da relative to the holding member 70 is restricted, and the tip member 50 can be temporarily fixed to the holding member 70.

[0042] The outer ribs 72 are formed to protrude radially outward from the outer peripheral surface of the retaining member 70. As shown in FIG. 4 , each outer rib 72 extends linearly along the axial direction da. When the retaining member 70 is attached to the front axle 20, the outer ribs 72 are positioned in the grooves 23 of the front axle 20. This prevents the retaining member 70 from rotating in the circumferential direction relative to the front axle 20. The multiple outer ribs 72 may be arranged at equal angular pitches from each other in the circumferential direction. In the present embodiment, the retaining member 70 has two outer ribs 72. The two outer ribs 72 are arranged at an angular pitch of 180 degrees from each other. This is not limiting, and the retaining member 70 may have three or more outer ribs 72.

[0043] The locking portion 74 is a portion that locks onto the locked portion 29 of the front axle 20 when the retaining member 70 is attached to the front axle 20. The locking portion 74 may be, for example, a convex portion or a concave portion formed on the outer peripheral surface of the retaining member 70. In the present embodiment, the locking portion 74 is an annular convex portion that is formed on the outer peripheral surface of the retaining member 70 and extends in the circumferential direction. When the retaining member 70 is attached to the front axle 20, the locking portion 74 climbs over the locked portion 29 and locks onto the locked portion 29. This prevents the retaining member 70 from slipping forward from the front axle 20. Note that the locking portion 74 is not limited to an annular convex portion, and may be, for example, an annular concave portion that is formed on the outer peripheral surface of the retaining member 70 and extends in the circumferential direction. In this case, the convex portion of the locked portion 29 fits into the concave portion of the locking portion 74, thereby locking the locking portion 74 to the locked portion 29. Furthermore, locked portion 29 of front axle 20 may be, for example, an annular recess formed on the inner peripheral surface of front axle 20 and extending circumferentially. In this case, the protrusion of locking portion 74 fits into the recess of locked portion 29, thereby locking portion 74 to locked portion 29. Locking portion 74 is located forward of claw portion 80.

[0044] The flange 75 is formed on the outer peripheral surface of the holding member 70. When the holding member 70 is attached to the front body 20, the flange 75 may come into contact with the front end of the front body 20.

[0045] The ventilation groove 77 is a groove formed across the outer peripheral surface of the holding member 70 and the rear surface of the flange 75. The internal space of the barrel 15 communicates with the outside via the ventilation groove 77. When the ink in the ink reservoir 11 decreases as a result of writing with the writing instrument 10, air flows into the internal space of the barrel 15 through the ventilation groove 77. This prevents the pressure in the internal space of the barrel 15 from becoming negative due to a decrease in ink, which would otherwise cause the flow of ink from the ink reservoir 11 to the tip member 50 to become stagnant.

[0046] The support portion 78 protrudes forward from the main body of the holding member 70. In this embodiment, the holding member 70 has two support portions 78, and the writing portion 52 of the tip member 50 is disposed between the two support portions 78. The support portion 78 is intended to contact a writing surface, such as a paper surface, when writing with the writing instrument 10. The front end of the support portion 78 is located rearward of the front end of the writing portion 52. In this embodiment, the writing portion 52 is flexible enough to bend in a direction perpendicular to the longitudinal direction of the cross section (lateral direction, left-right direction in FIG. 3 ) due to writing pressure. When writing, the support portion 78 comes into contact with the writing surface, thereby controlling the amount of bending of the writing portion 52 within a predetermined range. This prevents the writing portion 52 from being damaged or broken due to excessive bending. Furthermore, by moving the writing implement 10 while the two support portions 78 are in contact with the writing surface, the writing portion 52 can bend to a certain degree while writing, thereby enabling stable writing.

[0047] The multiple claws 80 have the function of restricting movement of the tip member 50 in the axial direction da relative to the holding member 70 when the holding member 70 is attached to the barrel 15 (front axle 20). The claws 80 extend rearward from the main body of the holding member 70. When the tip member 50 is disposed within the holding member 70, the claws 80 are disposed radially outward relative to the tip member 50. The rear ends of the claws 80 are configured to be deformable so that they can move radially inward. In particular, the claws 80 may be configured to be elastically deformable radially inward.

[0048] The multiple claw portions 80 may be arranged at equal angular pitches relative to one another in the circumferential direction. In this embodiment, the retaining member 70 has four claw portions 80. The four claw portions 80 are arranged at angular pitches of 90 degrees relative to one another. This is not limitative, and the retaining member 70 may have two, three, five or more claw portions 80. It is particularly preferable that the retaining member 70 have three or more claw portions 80. The retaining member 70 may have the same number of claw portions 80 as the number of groove portions 23 of the front axle 20.

[0049] The claw portions 80 may have protrusions 82, claw-side inclined surfaces 84, and inner inclined surfaces 86. The protrusions 82 are formed to protrude radially outward from the outer circumferential surfaces of the claw portions 80. As shown in FIG. 4 , one claw portion 80 has one protrusion 82. In this case, the retaining member 70 has the same number of protrusions 82 as the number of claw portions 80. In the present embodiment, the retaining member 70 has four protrusions 82. The protrusions 82 are formed at the circumferential centers of the corresponding claw portions 80. Therefore, the four protrusions 82 are arranged at an angular interval of 90 degrees from one another. Note that two or more protrusions 82 may be provided for one claw portion 80. When the retaining member 70 is attached to the front axle 20, the protrusions 82 are guided by the axle-cylinder-side inclined surfaces 25 of the front axle 20 and are subjected to a pressing force from the front axle 20 that deforms the claw portions 80 radially inward. The claw portion 80 has the protrusion 82, which makes it possible to reduce the radial thickness of the main body of the claw portion 80. Therefore, the claw portion 80 can be easily deformed radially inward.

[0050] A claw-side inclined surface 84 is provided at the rear end of protrusion 82. Claw-side inclined surface 84 is a surface that extends inward as it extends rearward. Claw-side inclined surface 84 has the function of cooperating with barrel-side inclined surface 25 of front body 20 to smoothly deform claw 80 radially inward. Furthermore, even if misalignment occurs between the central axis of retaining member 70 and the central axis of front body 20 when retaining member 70 is inserted into front body 20 from the front-end opening of front body 20, claw-side inclined surface 84 functions as a guide surface, allowing retaining member 70 to be smoothly inserted into front body 20.

[0051] The inner inclined surface 86 is provided on the inner surface of the claw portion 80. When the retaining member 70 is not attached to the barrel 15, the inner inclined surface 86 extends outward as it moves rearward (see FIG. 6A ). When the retaining member 70 is attached to the front axle 20 and the claw portion 80 is deformed inward, the inner inclined surface 86 becomes generally parallel to the outer circumferential surface of the tip member 50 (intermediate portion 54). This increases the contact area between the claw portion 80 and the tip member 50, making it possible to more appropriately restrict movement of the tip member 50 in the axial direction da relative to the retaining member 70.

[0052] Next, the process of attaching the tip member and the retaining member to the barrel will be described with reference to Figures 6A to 9D. Figures 6A to 9D are diagrams for explaining an example of the process of attaching the tip member 50 and the retaining member 70 to the barrel 15 (front axle 20).

[0053] Figure 6A is a diagram showing the tip member 50, the retaining member 70, and the front axle 20 before the retaining member 70 is attached to the front axle 20, and is a longitudinal cross-sectional view corresponding to line A-A in Figure 3. Figure 6B is a longitudinal cross-sectional view corresponding to line B-B in Figure 3 at the same time as Figure 6A. In this embodiment, the inner rib 71 and the claw portion 80 of the retaining member 70 are disposed at a 45-degree angle around the central axis A. In the longitudinal cross-sectional view corresponding to line A-A in Figure 3, the cross section of the claw portion 80 appears, but the cross section of the inner rib 71 does not appear. Furthermore, in the longitudinal cross-sectional view corresponding to line B-B in Figure 3, the cross section of the inner rib 71 appears, but the cross section of the claw portion 80 does not appear.

[0054] First, the tip member 50 is attached to the holding member 70. In this embodiment, the tip member 50 is inserted into the holding member 70 from the rear. The holding member 70 has an inner inclined surface 86 provided on the inner surface of the claw portion 80. As shown in FIG. 6A , when the holding member 70 is not attached to the barrel tube 15 (front axle 20), the inner inclined surface 86 extends outward toward the rear. In other words, the inner inclined surface 86 extends inward toward the front. Therefore, the tip member 50 that comes into contact with the inner inclined surface 86 and moves forward relative to the holding member 70 is guided by the inner inclined surface 86 and approaches the central axis A. In other words, the inner inclined surface 86 also functions as a guide surface when the tip member 50 is inserted into the holding member 70.

[0055] After the tip member 50 is inserted into the holding member 70, the writing portion 52 of the tip member 50 passes through the region of the holding member 70 where the inner rib 71 is formed and protrudes forward. The middle portion 54 of the tip member 50 is then pressed into the region of the holding member 70 where the inner rib 71 is formed. As a result, the outer circumferential surface of the tip member 50 (middle portion 54) is pressed against the inner rib 71 and deformed inward. At this time, a frictional force is generated between the outer circumferential surface of the tip member 50 (middle portion 54) and the inner rib 71. This temporarily secures the tip member 50 to the holding member 70. In this state, even if the holding member 70 is held with the writing portion 52 facing upward, for example, the tip member 50 is secured to the holding member 70 with a force strong enough to prevent the tip member 50 from falling out of the holding member 70 due to gravity.

[0056] Figure 7A is a diagram showing tip member 50, retaining member 70, and front body 20 when retaining member 70 has been inserted into front body 20 from the front of front body 20 and protrusion 82 of retaining member 70 has come into contact with barrel-side inclined surface 25 of front body 20, and is a longitudinal cross-sectional view corresponding to line A-A in Figure 3. Figure 7B is an enlarged view of the portion marked 7B in Figure 7A. Figure 7C is a longitudinal cross-sectional view corresponding to line B-B in Figure 3, at the same time point as Figure 7A. Figure 7D is an enlarged view of the portion marked 7D in Figure 7C.

[0057] Retaining member 70, to which tip member 50 is attached, is inserted into front axle 20 from the front. Retaining member 70 is inserted into front axle 20 so that protruding portion 82 of claw portion 80 enters groove portion 23 of front axle 20. While protruding portion 82 is positioned within groove portion 23, claw portion 80 does not deform in the radial direction. Thereafter, as shown in Figures 7A and 7B, protruding portion 82 of claw portion 80 comes into contact with barrel-side inclined surface 25 of groove portion 23.

[0058] Figure 8A is a diagram showing tip member 50, retaining member 70, and front axle 20 when retaining member 70 has moved further rearward relative to front axle 20 and protruding portion 82 of claw portion 80 is pressed against pressing surface 27 of front axle 20, and is a longitudinal cross-sectional view corresponding to line A-A in Figure 3. Figure 8B is an enlarged view of the portion labeled 8B in Figure 8A. Figure 8C is a longitudinal cross-sectional view corresponding to line B-B in Figure 3 at the same time as Figure 8A. Figure 8D is an enlarged view of the portion labeled 8D in Figure 8C.

[0059] When the retaining member 70 is further moved rearward relative to the front axle 20, the protruding portion 82 of the claw portion 80 is guided by the barrel-side inclined surface 25 of the groove portion 23 and moves radially inward. At this time, the claw portion 80 deforms radially inward (see FIGS. 8A and 8B ). This causes the claw portion 80 to contact the tip member 50. When the retaining member 70 is further moved rearward relative to the front axle 20, the protruding portion 82 is pressed radially inward by the pressing surface 27 located rearward of the barrel-side inclined surface 25. This causes the claw portion 80 to grip the tip member 50 with a relatively large force, restricting movement of the tip member 50 in the axial direction da relative to the retaining member 70. Note that at this time, the inner inclined surface 86 of the claw portion 80 becomes approximately parallel to the outer peripheral surface of the tip member 50 (intermediate portion 54). This increases the contact area between the claws 80 and the tip member 50, and reduces the radial deformation of the tip member 50 even when the claws 80 grip the tip member 50 with a relatively large force. Therefore, the flow of ink inside the tip member 50 is not impeded.

[0060] At this point, the locking portion 74 of the holding member 70 is positioned forward of the locked portion 29 of the front axle 20, and the locking portion 74 is not locked to the locked portion 29 (see Figures 8C and 8D).

[0061] Figure 9A is a diagram showing tip member 50, retaining member 70, and front axle 20 when retaining member 70 has moved further rearward relative to front axle 20 and protruding portion 82 of claw portion 80 is pressed against pressing surface 27 of front axle 20, and is a longitudinal cross-sectional view corresponding to line A-A in Figure 3. Figure 9B is an enlarged view of the portion marked 9B in Figure 9A. Figure 9C is a longitudinal cross-sectional view corresponding to line B-B in Figure 3 at the same time as Figure 9A. Figure 9D is an enlarged view of the portion marked 9D in Figure 9C.

[0062] When retaining member 70 is moved further rearward relative to front axle 20, locking portion 74 of retaining member 70 locks onto locked portion 29 of front axle 20, and retaining member 70 is fixed to front axle 20 (see FIGS. 9C and 9D ). In this embodiment, locking portion 74 is an annular convex portion formed on the outer circumferential surface of retaining member 70 and extending in the circumferential direction, and locked portion 29 is an annular convex portion formed on the inner circumferential surface of front axle 20 and extending in the circumferential direction. In this case, the convex portion of locking portion 74 rides over the convex portion of locked portion 29, thereby locking portion 74 to locked portion 29. When the convex portion of locking portion 74 rides over the convex portion of locked portion 29, a relatively large vibration is momentarily generated in retaining member 70. In this embodiment, after the claw portion 80 restricts the movement of the tip member 50 in the axial direction da relative to the holding member 70, the locking portion 74 locks with the locked portion 29. Therefore, even if a relatively large vibration occurs in the holding member 70, the tip member 50 is prevented from moving relative to the holding member 70.

[0063] The writing instrument 10 of this embodiment comprises a barrel 15, a tip member 50 having a writing portion 52 that forms handwriting, and a holding member 70 that is attached to the barrel 15 and holds the tip member 50. The holding member 70 has a plurality of ribs (inner ribs) 71 that protrude inward and contact the tip member 50, and a plurality of claw portions 80 that extend rearward and are positioned on the outside of the tip member 50. When the holding member 70 is attached to the barrel 15, the claw portions 80 deform inward and contact the tip member 50, thereby restricting movement of the tip member 50 in the axial direction da relative to the holding member 70.

[0064] With this writing instrument 10, the frictional force generated between the outer peripheral surface of the tip member 50 and the rib 71 temporarily fixes the tip member 50 to the holding member 70, and the claw portions 80 deform inward and contact the tip member 50, allowing the claw portions 80 to grip the tip member 50 with a relatively large force and restrict movement of the tip member 50 in the axial direction da relative to the holding member 70. As a result, even if a backward force acts on the tip member 50 due to writing pressure when writing with the writing instrument 10, the tip member 50 is prevented from moving backward relative to the holding member 70. Furthermore, even if a force in the axial direction da acts on the tip member 50 due to an impact such as being dropped on the writing instrument 10, the tip member 50 is prevented from moving in the axial direction da relative to the holding member 70. Therefore, the tip member 50 can be more firmly fixed with a simple configuration.

[0065] In the writing instrument 10 of this embodiment, the rib 71 extends linearly in the axial direction da.

[0066] According to this writing instrument 10, the tip member 50 can be easily inserted into the holding member 70.

[0067] The writing instrument 10 of this embodiment has three or more claw portions 80 .

[0068] According to this writing instrument 10, the tip member 50 can be more firmly fixed by the three or more claw portions 80.

[0069] The writing instrument 10 of this embodiment is provided with a barrel-side inclined surface 25 that is provided on the inner surface of the barrel 15 and extends inward as it moves toward the rear, and / or a claw-side inclined surface 84 that is provided on the outer surface of the claw portion 80 and extends inward as it moves toward the rear.

[0070] With such writing instrument 10, claw portion-side inclined surface 84 cooperates with barrel-side inclined surface 25 of front barrel 20, allowing claw portion 80 to be smoothly deformed radially inward. Furthermore, even if misalignment occurs between the central axis of retaining member 70 and the central axis of front barrel 20 when retaining member 70 is inserted into front barrel 20 from the front-end opening of front barrel 20, claw portion-side inclined surface 84 functions as a guide surface, allowing retaining member 70 to be smoothly inserted into front barrel 20.

[0071] The writing instrument 10 of this embodiment includes a protrusion 82 formed on the outer surface of the nail portion 80 .

[0072] According to this writing instrument 10, the claw portion 80 has the protrusion 82, which makes it possible to reduce the radial thickness of the main body of the claw portion 80. Therefore, the claw portion 80 can be easily deformed radially inward.

[0073] The writing instrument 10 of this embodiment has an inner inclined surface 86 that is provided on the inner surface of the claw portion 80 and extends outward as it moves rearward when the holding member 70 is not attached to the barrel 15.

[0074] With this writing instrument 10, when the retaining member 70 is attached to the front barrel 20 and the pawl portion 80 is deformed inward, the inner inclined surface 86 becomes generally parallel to the outer peripheral surface of the tip member 50 (intermediate portion 54). This increases the contact area between the pawl portion 80 and the tip member 50, making it possible to more appropriately restrict movement of the tip member 50 in the axial direction da relative to the retaining member 70.

[0075] Furthermore, when the tip member 50 is inserted into the holding member 70 from the rear, the tip member 50 comes into contact with the inner inclined surface 86 and moves forward relative to the holding member 70, and is guided by the inner inclined surface 86 to approach the central axis A. In other words, the inner inclined surface 86 also functions as a guide surface when the tip member 50 is inserted into the holding member 70.

[0076] The writing instrument 10 of this embodiment has an engaging portion 74 provided on the outer surface of the holding member 70 and an engaging portion 29 provided on the inner surface of the barrel 15, and when the holding member 70 is attached to the barrel 15, the engaging portion 74 engages with the engaging portion 29.

[0077] According to such writing instrument 10, retaining member 70 is fixed to front barrel 20 by locking portion 74 and locked portion 29. Therefore, retaining member 70 and front barrel 20 can be fixed to each other with a relatively simple configuration.

[0078] In the writing instrument 10 of this embodiment, the locking portion 74 is located forward of the claw portion 80 .

[0079] In the writing instrument 10 of this embodiment, when the holding member 70 is attached to the barrel 15 from the front, the claw portion 80 restricts the movement of the tip member 50 in the axial direction da relative to the holding member 70, and then the locking portion 74 locks onto the locked portion 29.

[0080] When the convex portion of locking portion 74 passes over the convex portion of locked portion 29, a relatively large vibration is momentarily generated in holding member 70. According to writing instrument 10 of this embodiment, after claw portion 80 restricts movement of tip member 50 in the axial direction da relative to holding member 70, locking portion 74 locks with locked portion 29. Therefore, even if a relatively large vibration is generated in holding member 70, tip member 50 is prevented from moving relative to holding member 70.

[0081] Modifications of this embodiment will be described with reference to Figures 10 to 27. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described embodiment will be designated by the same reference numerals as those used for the corresponding parts in the above-described embodiment, and duplicated descriptions will be omitted.

[0082] When manufacturing the writing instrument 10, the components constituting the writing instrument 10 are transported and assembled using a parts feeder or the like. In this process, when a holding member 70 is transported using a parts feeder or the like, the claw portions 80 of one holding member 70 may become entangled with another holding member 70, making them difficult to separate. In this case, the entangled holding members 70 cannot be assembled as is, and an operator must manually separate the two holding members 70. This causes inconvenience in the manufacture of the writing instrument 10. The present inventors have investigated this phenomenon of two holding members 70 becoming entangled, and have found two causes for this phenomenon. The first cause is that the claw portions 80 of another holding member 70 become caught in the gap 85 formed between two circumferentially adjacent claw portions 80, preventing them from being removed. The second cause is that the main body portion 73 of another holding member 70 becomes caught in the gap 85 formed between two circumferentially adjacent claw portions 80, preventing them from being removed.

[0083] 24 and 25 are diagrams for explaining the first cause and show an example of how the claw portions 80 of a holding member 70 become entangled. As particularly clearly shown in FIG. 25 , the two holding members 70 become entangled when the claw portions 80 of another holding member 70 become caught in a gap 85 formed between two circumferentially adjacent claw portions 80. This can occur when the width dimension of the gap 85 and the radial thickness of the claw portions 80 of the other holding member 70 are approximately equal. This can occur particularly when the radial thickness of the claw portions 80 of one holding member 70 is slightly larger than the width dimension of the gap 85 of the other holding member 70. This occurs because when the claw portions 80 of one holding member 70 enter the gap 85 of the other holding member 70, the claw portions 80 of the other holding member 70 elastically deform, and the force of the claw portions 80 trying to return to their original shape presses down on the claw portions 80 located within the gap 85.

[0084] In order to solve this problem, in this modified example, we considered reducing the gap 85 formed between two circumferentially adjacent claw portions 80, thereby preventing the claw portions 80 of other retaining members 70 from entering the gap 85.

[0085] 26 and 27 are diagrams for explaining the second cause and show an example of how the claw portions 80 of a holding member 70 become entangled. As particularly clearly shown in FIG. 27 , the main body portion 73 of another holding member 70 becomes caught in a gap 85 formed between two circumferentially adjacent claw portions 80, causing the two holding members 70 to become entangled. This can occur when the width of the gap 85 and the radial thickness of the main body portion 73 of the other holding member 70 are approximately equal. This is particularly likely to occur when the radial thickness of the main body portion 73 of one holding member 70 is slightly larger than the width of the gap 85 of the other holding member 70. This occurs because when the main body portion 73 of one holding member 70 enters the gap 85 of the other holding member 70, the claw portions 80 of the other holding member 70 elastically deform, and the force of the claw portions 80 attempting to return to their original shape presses against the main body portion 73 located within the gap 85.

[0086] To solve this problem, in this modified example, we considered increasing the radial thickness of the main body 73 of the holding member 70 to prevent the main body 73 of another holding member 70 from entering the gap 85.

[0087] 10 to 23, the holding member 70 has an entanglement prevention portion 90 that prevents the claw portions 80 of the holding member 70 from entangling with other holding members 70. The entanglement prevention portion 90 will be described below.

[0088] Fig. 10 is a perspective view showing a modified example of the holding member 70. Fig. 11 is a side view showing the holding member 70 of Fig. 10. Fig. 12 is a view showing the claw portion 80 of the holding member 70 of Fig. 10 as viewed from the tip portion 88 side. Fig. 13 is a half-split perspective view showing the holding member 70 of Fig. 10. Fig. 14 is a vertical cross-sectional view showing the holding member 70 of Fig. 10. Fig. 15 is a cross-sectional view corresponding to line XV-XV in Fig. 11.

[0089] 10 and 11, the holding member 70 includes a main body 73 and a claw 80. The claw 80 extends rearward from the main body 73. In the examples shown in FIGS. 10 to 23, the support portion 78 is not shown. The holding member 70 may also include an outer rib 72, a locking portion 74, and a ventilation groove 77, similar to the holding member 70 in the example shown in FIG.

[0090] Each claw portion 80 has a base end portion 87, a tip end portion 88, and a side surface 89. The base end portion 87 is a portion of the claw portion 80 that connects to the main body portion 73. The tip end portion 88 is an end portion of the claw portion 80 opposite the base end portion 87. The tip end portion 88 is a free end. The side surface 89 is a surface that connects the outer peripheral surface and the inner peripheral surface of the claw portion 80. The side surface 89 may extend parallel to the axial direction da. One claw portion 80 has two side surfaces 89. The two side surfaces 89 of one claw portion 80 may extend parallel to each other. However, this is not limited to this, and the two side surfaces 89 may extend so as to approach each other as they move radially outward.

[0091] 10 to 15, the holding member 70 includes two tangle suppression portions 90, a first tangle suppression portion 91 and a second tangle suppression portion 92. However, this is not limited thereto, and the holding member 70 may include only one of the first tangle suppression portion 91 and the second tangle suppression portion 92.

[0092] The first entanglement suppression portion 91 includes a bulge portion 94. The bulge portion 94 has the function of reducing the distance between two circumferentially adjacent claw portions 80. The bulge portion 94 protrudes in the circumferential direction from the side surface 89 of the claw portion 80. The specific protruding shape of the bulge portion 94 is not particularly limited. In the example shown in FIGS. 10 to 15 , the bulge portion 94 is provided at the tip end 88 of the claw portion 80. In the illustrated example, of the four claw portions 80, the bulge portion 94 is provided on two claw portions 80 that face each other across the central axis A. One claw portion 80 has a bulge portion 94 provided on one side surface 89 and a bulge portion 94 provided on the other side surface 89. Therefore, one claw portion 80 has a bulge portion 94 that protrudes to one circumferential side and a bulge portion 94 that protrudes to the other circumferential side. It is preferable that the bulge portion 94 protrudes from only a portion of the side surface 89, rather than from the entire side surface 89. This allows the amount of material used for the bulge portion 94 to be reduced compared to when the bulge portion 94 is formed on the entire side surface 89. This reduces the environmental impact and also prevents an increase in the cost of forming the bulge portion 94.

[0093] In the examples shown in FIGS. 10 to 15, the minimum distance D between two claws 80 adjacent in the circumferential direction is ｍｉｎ is smaller than the maximum radial thickness T1 of the claw portion 80. In the example shown in FIG. 12, the minimum distance D between two claw portions 80 adjacent in the circumferential direction is ｍｉｎ is the distance between the top of the bulge 94 and the side surface 89 of the claw portion 80 adjacent in the circumferential direction. In particular, in this embodiment, as clearly shown in FIG. 12, the minimum distance D between two claw portions 80 adjacent in the circumferential direction is ｍｉｎ is the shortest distance between the radially inner end of the apex of the bulge 94 and the radially inner end of the side surface 89 of the claw 80 that faces the bulge 94 in the circumferential direction. ｍｉｎ is smaller than the maximum thickness T1, the claw portions 80 of other holding members 70 are prevented from entering the gaps 85 formed between two circumferentially adjacent claw portions 80. Therefore, the claw portions 80 are prevented from becoming entangled with the claw portions 80 of other holding members 70.

[0094] Preferably, the minimum distance D between two circumferentially adjacent claw portions 80 is ｍｉｎ is smaller than the minimum radial thickness T2 of the claw portion 80. ｍｉｎ is smaller than the minimum thickness T2, the claw portions 80 of other holding members 70 are more effectively prevented from entering the gaps 85 formed between two circumferentially adjacent claw portions 80. Therefore, the claw portions 80 are further prevented from becoming entangled with the claw portions 80 of other holding members 70.

[0095] The second entanglement suppression portion 92 includes a thick portion 79. The thick portion 79 is formed in the main body portion 73. The radial thickness T3 of the thick portion 79 is equal to the minimum distance D between two circumferentially adjacent claw portions 80. ｍｉｎ In other words, the thick portion 79 is larger than the minimum distance D ｍｉｎ 27 , in consideration of the fact that the two holding members 70 become entangled when the main body 73 of another holding member 70 is caught in the gap 85 between the two claw portions 80, the thick portion 79 only needs to be provided in a portion adjacent to the gap 85 in the axial direction da when the holding member 70 is viewed from the radial direction.

[0096] 10 to 15, the inner rib 71 constitutes the thick portion 79. By forming only the inner rib 71 thick, it is possible to prevent an increase in the amount of material used in the entanglement suppression portion 90 while forming the thick portion 79. This reduces the environmental impact and also prevents an increase in the cost of forming the entanglement suppression portion 90. When the retaining member 70 is viewed from the radial direction, the inner rib 71 is arranged side by side in the axial direction da with the gap 85 between the two claw portions 80. However, this is not limited thereto, and the thick portion 79 may be formed in an annular shape extending in the circumferential direction.

[0097] The radial thickness T3 of the thick portion 79 is the minimum distance D between two circumferentially adjacent claw portions 80. ｍｉｎ The thickness T3 of the thick portion 79 in the radial direction is greater than the minimum distance D ｍｉｎ , the main body 73 of another holding member 70 is prevented from entering the gap 85 between the two claw portions 80. Therefore, the claw portion 80 is prevented from becoming entangled with the claw portion 80 of another holding member 70.

[0098] Fig. 16 is a perspective view showing another modified example of the holding member 70. Fig. 17 is a side view showing the holding member 70 of Fig. 16.

[0099] 16 and 17 , of the four claw portions 80, two claw portions 80 that face each other across the central axis A are provided with first entanglement suppression portions 91. In this modification, the side surfaces 89 are inclined with respect to the axial direction da and the circumferential direction so that the circumferential width of the claw portions 80 increases from the base end portion 87 toward the tip end portion 88. As a result, the width of the claw portions 80 is greatest at the tip end portion 88. In this modification, the side surfaces 89 at the tip end portion 88 form bulging portions 94.

[0100] In the examples shown in Figures 10 to 15 and the examples shown in Figures 16 and 17, the bulge portion 94 is formed at the tip portion 88 of the claw portion 80, which is preferable because it can prevent the claw portion 80 of another holding member 70 from entering the gap 85 between two claw portions 80 extending in the axial direction da in the portion on the tip portion 88 side of the gap 85.

[0101] 18 and 19 , of the four claw portions 80, two claw portions 80 that face each other across the central axis A are provided with a first entanglement suppression portion 91. In this modification, a bulge portion 94 is provided on the side surface 89 of each claw portion 80 in an intermediate portion between a base end portion 87 and a tip end portion 88.

[0102] 9A , when the claw portions 80 elastically deform radially inward, the bulging portions 94 are prevented from coming into contact with other claw portions 80 adjacent thereto in the circumferential direction. Therefore, it is possible to prevent the claw portions 80 from being prevented from elastically deforming inward.

[0103] 20 and 21 , each of the four claw portions 80 is provided with a first entanglement suppression portion 91. In this modification, of the four claw portions 80, two claw portions 80 that face each other across the central axis A are provided with bulging portions 94 at tip portions 88 on side surfaces 89 of the claw portions 80. Furthermore, of the four claw portions 80, the other two claw portions 80 that face each other across the central axis A are provided with bulging portions 94 in intermediate portions between the base ends 87 and the tip portions 88 on the side surfaces 89 of the claw portions 80.

[0104] In this modified example, the bulge 94 provided at the tip end 88 of the claw portion 80 can prevent the claw portion 80 of another holding member 70 from entering the gap 85 between the two claw portions 80 at the tip end 88 side of the gap 85. Furthermore, the bulge 94 provided at the middle portion of the claw portion 80 can also prevent the claw portion 80 of another holding member 70 from entering the gap 85 at the middle portion of the gap 85 between the two claw portions 80. Therefore, it is possible to more effectively prevent the claw portion 80 of another holding member 70 from entering the gap 85 between the two claw portions 80. Furthermore, since the positions of the bulge portions 94 of two circumferentially adjacent claw portions 80 are shifted in the axial direction da, contact between two circumferentially adjacent bulge portions 94 is prevented when the claw portions 80 elastically deform radially inward.

[0105] 22 and 23, each of the four claws 80 is provided with a first entanglement suppression portion 91. In this modification, each of the four claws 80 is provided with a bulge 94 at a tip end 88 of a side surface 89 of the claw 80. In this modification, the minimum distance D between two claws 80 adjacent in the circumferential direction is ｍｉｎ Therefore, it is possible to more effectively prevent the claw portion 80 of another holding member 70 from entering the gap 85 between the two claw portions 80.

[0106] 16 to 23, similarly to the modifications described with reference to FIGS. 10 to 15, the minimum distance D between two claw portions 80 adjacent in the circumferential direction is ｍｉｎ is preferably smaller than the maximum radial thickness T1 of the claw portion 80. In addition, the minimum distance D between two claw portions 80 adjacent in the circumferential direction is ｍｉｎ is more preferably smaller than the minimum radial thickness T2 of the claw portion 80.

[0107] 16 to 23, similarly to the modified example described with reference to Figures 10 to 15, the holding member 70 may have a thick portion 79. In this case, the specific configuration and effects thereof are similar to those of the modified example described with reference to Figures 10 to 15, and therefore detailed description thereof will be omitted.

[0108] The ink contained in the ink reservoir 11 may be either a water-based ink or an oil-based ink for writing. In addition, the ink may be imparted with thixotropy by adding a shear thinning agent to the ink.

[0109] The colorant contained in the ink may be a non-discoloring colorant selected from the group consisting of dyes, pigments, and resin particles. Examples of dyes include acid dyes, basic dyes, and direct dyes. Examples of pigments include inorganic pigments, organic pigments, luster pigments, metallic powder pigments, fluorescent pigments, and phosphorescent pigments. The pigment may be a microencapsulated pigment in which the dye or pigment is encapsulated in a microcapsule. Examples of resin particles include white resin particles that do not contain a colorant, and colored resin particles that contain a dye or pigment. Examples of colored resin particles include colored resin particles in which a dye is homogeneously dissolved or dispersed in resin particles, colored resin particles in which a dye is dyed into resin particles, colored resin particles in which a pigment is dispersed in resin particles, and colored resin particles in which the surface of resin particles is coated with a pigment. Resin particles include solid resin particles and hollow resin particles.

[0110] The colorant contained in the ink may be a colorant containing a thermochromic material that changes color depending on temperature. As the thermochromic material, a reversible thermochromic material is preferred because it can repeatedly exhibit color changes due to temperature changes.

[0111] Examples of reversible thermochromic materials include reversible thermochromic compositions containing at least three essential components: (A) an electron-donating organic color-forming compound, (B) an electron-accepting compound, and (C) a reaction medium that determines the temperature at which the color-changing reaction between the two occurs.The reversible thermochromic material may be a reversible thermochromic microcapsule pigment in which the reversible thermochromic composition is encapsulated in microcapsules, or reversible thermochromic resin particles in which the reversible thermochromic composition is dispersed in resin particles.

[0112] Reversible thermochromic materials include materials of the thermal decolorization type, color memory retention type, and thermal color development type. Thermal decolorization type materials are materials that are decolorized by heating from a colored state. Color memory retention type materials are materials that reversibly change from a colored state to a decolorized state or from a decolorized state to a colored state in response to temperature changes, and maintain the colored state or decolorized state within a specific temperature range. Thermal color development type materials are materials that develop color when heated from a decolorized state and return to the decolorized state when cooled from the colored state. One type of reversible thermochromic material may be used alone, or multiple types of reversible thermochromic materials may be used in combination.

[0113] By using a combination of a non-color-changing colorant and a reversible thermochromic colorant as colorants in the ink, a reversible color change from a first color to a second color can be achieved. This is because the reversible thermochromic colorant reversibly changes color from a colored state to a decolorized state due to a change in temperature. Here, the "first color" refers to the color exhibited by the reversible thermochromic colorant when it is in a colored state, and is a mixture of the color due to the reversible thermochromic colorant in its colored state and the color due to the non-color-changing colorant. The "second color" refers to the color exhibited by the reversible thermochromic colorant when it is in a decolorized state, and is the color due to the non-color-changing colorant alone. The reversible color change from the first color to the second color includes a change in color tone (e.g., from a dark color to a light color) or a change in hue (e.g., from purple to pink, or from green to yellow).

[0114] The writing instrument 10 may include a friction body 18 for frictioning handwriting. Fig. 28 is a diagram showing a modified example of the writing instrument 10, and is an external view showing an example of a writing instrument 10 having the friction body 18. Fig. 29 is a diagram showing a modified example of the friction body 18. Fig. 30 is a diagram showing another modified example of the friction body 18. Fig. 31 is a diagram showing yet another modified example of the friction body 18. Fig. 32 is a diagram showing the friction body 18 of Fig. 31 as seen from the front. In Figs. 28 to 32, the friction body 18 is hatched.

[0115] The friction body 18 is a member for rubbing the ink mark. When the ink contains a thermochromic material, the friction body 18 has the function of rubbing the writing surface, such as the surface of paper, on which the handwriting is formed, and heating the ink that forms the handwriting by the frictional heat generated between the friction body 18 and the writing surface. The friction body 18 can be made of, for example, an elastic material.

[0116] In the example shown in Fig. 28, a friction body 18 is provided at the rear end of the rear cap 13 of the writing instrument 10. In the example shown in Fig. 29, friction bodies 18 are provided at the front end of the front cap 16 and the front end of the clip 17 of the front cap 16. The front cap 16 is a member that covers the tip member 50 and prevents the ink in the tip member 50 from drying. In the example shown in Fig. 29, the friction body 18 may be provided at only one of the front end of the front cap 16 or the front end of the clip 17.

[0117] 30, the friction body 18 is provided at the front end of the support portion 78 of the holding member 70. In the example shown in Fig. 30, the friction body 18 is provided at the front end of both of the two support portions 78, but this is not limiting, and the friction body 18 may be provided at the front end of only one of the two support portions 78.

[0118] 31 and 32 , a friction body 18 is provided at the front end of one of the support portions 78. The friction body 18 has a protruding portion 19 that protrudes in a direction perpendicular to the axial direction da and the radial direction. With this type of friction body 18, the friction body 18 (protruding portion 19) protrudes to the side of the writing part 52, so that the friction body 18 can be easily brought into contact with the writing surface without bringing the writing part 52 into contact with the writing surface.

[0119] 33 is a perspective view showing a modified example of the tip member 50 and the support portion 78. In this modified example, the writing portion 52 of the tip member 50 is formed so that its thickness decreases toward the front, and a convex curved surface is formed at the front end of the writing portion 52. The support portion 78 is also formed so that its thickness decreases toward the front, and a convex curved surface is formed at the front end of the support portion 78.

[0120] In the above-described embodiment and modified example, the pair of support portions 78 contact the writing surface, so that when a ruler or the like is used to draw a line on paper, the support portion 78 located closest to the ruler or the like can make line or surface contact with the ruler or the like. This allows for stable writing and makes it easy to draw a line as intended. Furthermore, even when writing without a ruler or the like, the direction in which the writing portion 52 is bent (sunk into the paper) and the direction in which the writing portion 52 is moved are the same. Therefore, even when writing without a ruler or the like, it is easy to draw a line as intended.

[0121] In the above-described embodiment and modified example, when a ruler or the like is used to draw a line on a writing surface, the support portion 78 abuts the ruler or the like, preventing the pen tip 2 from coming into direct contact with the ruler or the like. This prevents ink from adhering to the ruler and staining the ruler. It also prevents stains on the ruler from re-adhering to the writing part 52 of another writing instrument 10 and staining the writing part 52.

[0122] Furthermore, because the holding member 70 has a pair of support portions 78, when the writing part 52 is inserted into the front cap 16 of the writing instrument 10, the writing part 52 comes into contact with the inner surface of the front cap 16, which can prevent ink from adhering to the inner surface of the front cap 16. If ink adheres to the inner surface of the front cap 16, the ink adhering to the inner surface of the front cap 16 will adhere to the outer surface of the barrel 15 (front barrel 20) when the front cap 16 is fitted to the writing instrument 10. In this case, when the user removes the front cap 16 again and grips the barrel 15 (front barrel 20) of the writing instrument 10, the ink adhering to the outer surface of the barrel 15 (front barrel 20) may adhere to the user's hands, causing them to become dirty.

[0123] When the writing part 52 is not in contact with the writing surface (when not writing), the writing part 52 and the support part 78 are positioned so as to overlap with the central axis A of the writing instrument 10 when viewed from the direction in which the two support parts 78 overlap each other. On the other hand, when the writing part 52 is in contact with the writing surface and writing pressure is applied (when writing), the writing part 52 bends due to the writing pressure, and when viewed from the direction in which the two support parts 78 overlap each other, the writing part 52 is positioned offset to the side of the support part 78. In this case, the entire writing part 52 is in contact with the writing surface regardless of the angle of the writing part 52 relative to the writing surface, which has the advantage of stabilizing the width of the handwritten line.

[0124] In the above-described embodiment and modified examples, the holding member 70 has two support portions 78, but is not limited to this, and the holding member 70 may have one support portion 78. For example, the holding member 70 may have only the support portion 78 intended to be positioned on the front side when writing with the writing instrument 10 (the left support portion 78 in FIG. 2 ).

[0125] Furthermore, it is preferable that the color of the holding member 70 be different from the color of the writing portion 52 (i.e., the color of the ink). This makes it easier to visually distinguish the holding member 70 from the writing portion 52, and makes it easier to confirm the orientation of the writing portion 52. In particular, if the writing portion 52 itself is colored a dark color such as black, and the holding member 70 is colored a light color different from the writing portion 52, the holding member 70 will be even easier to visually distinguish from the writing portion 52, and the shape of the writing portion 52 will be easier to confirm.

[0126] Furthermore, the entire holding member 70 may be made of a transparent or translucent material. In this case, the tip member 50 can be seen through the holding member 70, making it easier to see the color of the ink. This also provides an excellent design (aesthetics).

[0127] As another example, only the portion near the front end of the holding member 70 may be colored, with the remainder being made of a transparent or translucent material. This configuration has the advantage that, when the color of the writing surface and the color of the ink are similar, it becomes easier to grasp the relative positions of the writing instrument 10 and the writing surface.

[0128] The top of the writing part 52 may be formed to be substantially linear in side view. Furthermore, the rear edge 76 (see FIG. 33 ) of the opening located between the two support parts 78 may also be formed to be substantially linear in side view. Furthermore, the top and rear edge 76 of the writing part 52 may extend parallel to each other in side view. In this case, the load on the tip member 50 caused by bending of the tip member 50 is applied evenly to the writing part 52, preventing localized stress concentration in the writing part 52 and extending the life of the writing part 52.

[0129] During memorization work in learning, handwriting may be written with the writing instrument 10 so as to cover a character string on the writing surface (for example, a character string in a textbook), and a colored sheet member may be placed over the handwriting to make the character string less visible. The writing instrument 10 of the above-described embodiment and modified example may be used together with such a sheet member.

[0130] The color of the ink contained in the writing instrument 10 and the color of the sheet member may be complementary to each other. For example, the color of the ink contained in the writing instrument 10 may be a greenish color, and the color of the sheet member may be a reddish, transparent color. Alternatively, the color of the ink contained in the writing instrument 10 may be a reddish color, and the color of the sheet member may be a greenish, transparent color. Furthermore, the relationship between the color of the ink contained in the writing instrument 10 and the color of the sheet member need only be complementary to each other, and is not limited to the combination of greenish and reddish.

[0131] In this case, when a sheet member is placed on handwriting made by the writing instrument 10, the handwriting made by the writing instrument 10 appears black. In this case, when handwriting is written on a character string on the writing surface with the writing instrument 10 and a sheet member is placed on this handwriting, the character string on the writing surface appears to be filled in black, making it difficult for the user to distinguish the character string on the writing surface.

[0132] If the color of the ink contained in the writing instrument 10 and the color of the sheet member are complementary to each other and the material constituting the sheet member is soft, the flexibility of the sheet member allows the sheet member to properly conform to a curved surface such as the pages of an open book. Note that a colored writing pad or ruler may be used instead of such a sheet member.

Claims

1. A writing instrument comprising: a barrel; a tip member having a writing portion for forming handwriting; and a retaining member attached to the barrel and holding the tip member, wherein the retaining member has a number of ribs that protrude inward and contact the tip member, and a number of claw portions that extend rearward and are positioned on the outside of the tip member, and when the retaining member is attached to the barrel, the claw portions deform inward and contact the tip member, thereby restricting axial movement of the tip member relative to the retaining member.

2. The writing implement according to claim 1, wherein said rib extends linearly in the axial direction.

3. The writing instrument according to claim 1, comprising three or more of said prongs.

4. A writing instrument as described in claim 1, comprising a barrel-side inclined surface provided on the inner surface of the barrel and extending inward as it approaches the rear, and / or a claw-side inclined surface provided on the outer surface of the claw portion and extending inward as it approaches the rear.

5. The writing implement according to claim 1, further comprising a protrusion formed on an outer surface of said prong portion.

6. A writing implement as described in claim 1, further comprising an inner inclined surface provided on the inner surface of the claw portion and extending outwardly toward the rear when the holding member is not attached to the barrel.

7. A writing instrument as described in claim 1, comprising a locking portion provided on the outer surface of the holding member and a locked portion provided on the inner surface of the barrel, wherein the locking portion locks with the locked portion when the holding member is attached to the barrel.

8. The writing implement according to claim 7, wherein the engaging portion is located forward of the claw portion.

9. A writing instrument as described in claim 7 or 8, wherein when the retaining member is attached to the barrel from the front, the locking portion locks into the locked portion after the claw portion restricts axial movement of the tip member relative to the retaining member.

10. The writing implement according to claim 1, wherein the minimum distance between two adjacent claw portions in the circumferential direction is smaller than the maximum radial thickness of the claw portions.

11. The writing implement according to claim 1, wherein the minimum distance between two adjacent claw portions in the circumferential direction is smaller than the minimum radial thickness of the claw portions.

12. The writing implement according to claim 10 or 11, wherein the holding member has a bulge that reduces the distance between two of the claw portions that are adjacent in the circumferential direction.

13. A writing instrument as described in claim 1, wherein the retaining member has a main body portion and the claw portion extending from the main body portion, the retaining member has a thick portion formed in the main body portion, and the radial thickness of the thick portion is greater than the minimum distance between two of the claw portions adjacent to each other in the circumferential direction.

14. A writing instrument as described in claim 13, wherein the rib constitutes the thick portion, and when the retaining member is viewed radially, the rib is arranged in axial alignment with a gap formed between two adjacent claw portions.