Writing instrument

Abstract

A writing instrument (10) is provided with: a shaft tube (20) having an opening (22a); a writing member (12) having a pen tip (13); an access mechanism (40) for accessing the pen tip (13) from the opening (22a); and a sealing mechanism (70) for sealing the accommodation space (S) of the pen tip (13) when the pen tip (13) is in a retracted state, the sealing mechanism (70) being provided with: a cover member (72) for closing the opening (22a) by coming into contact with a contact surface (22b) surrounding the opening (22a); and a negative pressure suppression mechanism (80) that suppresses the pressure within the housing space (S) to become negative pressure.

Description

Technical Field

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

[0002] Conventionally, a writing instrument having a shaft tube, a writing member, and an insertion / removal mechanism has been known. The writing member has a nib, and the insertion / removal mechanism causes the nib to be inserted into and removed from the shaft tube. Further, in such a writing instrument, in order to prevent the ink at the nib from drying in the state where the nib is retracted, a writing instrument having a sealing mechanism for sealing the storage space of the nib has also been known.

[0003] JP2007 - 112032A discloses a writing instrument having: a shaft tube; a writing body housed inside the shaft tube; a cap disposed in front of the shaft tube; and a spring that biases the cap in a closing direction. In this writing instrument, when the writing body moves forward, the cap is pressed against the front end of the writing body and opened. Further, when the writing body moves backward in this state, the writing body is housed inside the shaft tube, and the cap is closed by the elastic force of the spring to seal the shaft tube. Thereby, during the period when the writing body is housed in the shaft tube, it is possible to prevent the ink in the writing body from drying.

[0004] In an existing writing instrument having a sealing mechanism, as the writing body retracts, the cap closes, and then the writing body further retracts and is housed inside the shaft tube. At this time, after the cap closes and the writing body retracts, a negative pressure may sometimes be generated inside the storage space of the writing body. In this case, the ink housed inside the writing body may leak into the storage space through the nib of the writing body. Summary of the Invention

[0005] The present invention has been made in consideration of such points, and an object thereof is to suppress the ink in the writing body from leaking into the storage space of the writing body.

[0006] [1]. The present invention provides a writing instrument having: a shaft tube having an opening; a writing member having a nib; an insertion / removal mechanism that causes the nib to be inserted into and removed from the opening; and a sealing mechanism that seals the storage space of the nib in a state where the nib is retracted. The sealing mechanism has: a cap member that contacts a contact surface surrounding the opening to close the opening; and a negative pressure suppression mechanism that suppresses the pressure in the storage space from becoming negative.

[0007] [2]. The writing instrument according to [1], wherein the negative pressure suppression mechanism has a closing delay mechanism that delays the timing at which the cap member closes the opening.

[0008] [3]. The writing instrument according to [2], wherein the cap member has an opposing surface opposing the contact surface, and the closing delay mechanism includes an elastically deformable portion provided on the contact surface or the opposing surface.

[0009] [4]. The writing instrument according to [3], wherein the elastically deformable portion is a protruding portion protruding from the contact surface or the opposing surface.

[0010] [5]. The writing instrument according to [4], wherein the protruding portion at least partially surrounds the opening portion.

[0011] [6]. The writing instrument according to [4] or [5], wherein the height of the protruding portion in a direction perpendicular to the contact surface or the opposing surface decreases as it is farther from the rotation axis of the cap member.

[0012] [7]. The writing instrument according to any one of [1] to [6], wherein the rotation axis of the cap member is located on the opposite side of the storage space with respect to the extension plane of the contact surface.

[0013] According to the present invention, it is possible to suppress ink in the writing body from leaking into the storage space of the writing body. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a longitudinal sectional view showing an example of a writing instrument in a submerged state for explaining an embodiment of the present invention.

[0015] Figure 2 is a longitudinal sectional view showing Figure 1 the writing instrument in a protruding state.

[0016] Figure 3 is a longitudinal sectional view showing an enlarged front portion of Figure 1 the writing instrument.

[0017] Figure 4 is a view showing an example of the negative pressure suppression mechanism of the writing instrument as observed from the front.

[0018] Figure 5 is a longitudinal sectional view showing an example of the negative pressure suppression mechanism.

[0019] Figure 6 is a view showing an enlarged portion Figure 5 labeled VI of

[0020] Figure 7 is a view showing an enlarged portion Figure 6 labeled VII of

[0021] Figure 8It is a longitudinal sectional view showing a part of the negative pressure suppression mechanism.

[0022] Figure 9 It is a view that Figure 8 enlargely shows the part marked IX.

[0023] Figure 10 It is a view for explaining the operation of the negative pressure suppression mechanism.

[0024] Figure 11 It is a view for explaining the operation of the negative pressure suppression mechanism.

[0025] Figure 12 It is a view that Figure 11 enlargely shows the part marked XII. Detailed Embodiment

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in the accompanying drawings attached to this specification, for the convenience of illustration and understanding, the scale and the aspect ratio in the vertical and horizontal directions, etc., are appropriately changed and exaggerated with respect to the scale and the aspect ratio of the actual object.

[0027] In addition, regarding terms such as "parallel", "perpendicular", "identical", etc., which are used to determine shapes, geometric conditions, and their degrees in this specification, and values such as lengths and angles, they are not strictly limited, and are interpreted to include ranges of degrees that can expect the same functions.

[0028] In this specification, the direction (length direction) in which the central axis A of the writing instrument 10 extends is defined as the axial direction da, the direction perpendicular to the axial direction da is defined as the radial direction, and the direction along the circumference around the central axis A is defined as the circumferential direction. Along the axial direction da, the nib side is set as the front, and the side opposite to the nib is set as the rear. In addition, along the radial direction, the side closer to the central axis A is set as the inner side or the inner direction, and the side farther from the central axis A is set as the outer side or the outer direction.

[0029] Figure 1 It is a view for explaining an embodiment of the present invention, and is a longitudinal sectional view showing an example of the writing instrument 10 in a submerged state. Figure 2 It is a longitudinal sectional view showing the writing instrument 10 in a protruding state.

[0030] The writing instrument 10 of the present embodiment includes a writing member 12, a shaft tube 20, an insertion / removal mechanism 40, and a sealing mechanism 70. The writing instrument 10 extends along the central axis A. The writing member 12 is a member that forms a writing trace on a writing surface such as a paper surface. The writing member 12 is housed inside the shaft tube 20. Examples of the writing member 12 include members used in ballpoint pens, fountain pens, markers, etc. In the present embodiment, an example where the writing instrument 10 is a fountain pen will be described. The writing member 12 of the present embodiment has a nib 13 provided at the front end, an ink storage cylinder 15 that stores ink, a first receiving portion 17, and a protruding portion 19. The ink storage cylinder 15 can be, for example, a cartridge type or a converter. The first receiving portion 17 is the front-facing surface among the stepped portions formed on the outer surface of the writing member 12, and receives the elastic force of the first elastic member 42 described later. The protruding portion 19 protrudes radially outward from the main body portion of the writing member 12.

[0031] The insertion / removal mechanism 40 is a mechanism for alternately switching the writing instrument 10 between a protruding state where the nib 13 protrudes from the front end opening 20a of the shaft tube 20 and a retracted state where the nib 13 retracts from the front end opening 20a.

[0032] The shaft tube 20 includes a front shaft 21, a front end member 30 disposed in front of the front shaft 21, and a rear shaft 31 disposed behind the front shaft 21. The central axis of the shaft tube 20 coincides with the central axis A of the writing instrument 10. A front end opening 20a through which the nib 13 can pass is provided at the front end of the shaft tube 20. In the present embodiment, the front end opening 20a is formed at the front end of the front end member 30.

[0033] The front shaft 21 is a member having a substantially cylindrical shape and is intended to be grasped by a finger when the user writes with the writing instrument 10. The front shaft 21 of the present embodiment includes an inner shaft 22, an outer shaft 25 disposed radially outside the inner shaft 22, and a first connecting member 26.

[0034] The inner shaft 22 is a component that stores the front part of the writing member 12 and defines the storage space S of the pen tip 13. The inner shaft 22 is a component having a substantially cylindrical shape having a central axis that coincides with the central axis A. In the present embodiment, the inner shaft 22 stores the entire pen tip 13 in the submerged state. A groove 24 that engages with the protrusion 19 of the writing member 12 is formed on the inner surface of the inner shaft 22. The groove 24 is a groove extending along the axial direction da, and the protrusion 19 of the writing member 12 is located in the groove 24, thereby the writing member 12 is supported to be movable along the axial direction da relative to the shaft cylinder 20 and not rotatable in the circumferential direction. The inner shaft 22 is formed of, for example, a resin material such as acrylonitrile-styrene (AS) copolymer resin, acrylonitrile-butadiene-styrene (ABS) copolymer resin, polycarbonate (PC), polypropylene (PP), polyethylene (PE), elastomer, a rubber material such as nitrile rubber (NBR), etc. In addition, the inner shaft 22 can be composed of a single component or a plurality of components.

[0035] An opening 22a through which the pen tip 13 can pass is formed at the front end of the inner shaft 22. A contact surface 22b is formed around the opening 22a. The contact surface 22b is a surface that contacts the cover member 72 described later in the submerged state. The manner in which the contact surface 22b contacts the cover member 72 will be described later.

[0036] The outer shaft 25 is a component visually confirmed by the user, and is a component that the user grasps with his fingers when writing with the writing instrument 10. Therefore, in consideration of the design and the ease of gripping by the user, the outer shaft 25 is formed of an appropriate material. For example, the outer shaft 25 may also be formed of a resin, an elastomer, a metal, a wood, or the like. The first connecting member 26 is a member constituting a connecting portion with the rear shaft 31. The first connecting member 26 is fixed to the rear end portion of at least one of the inner shaft 22 and the outer shaft 25. For example, the first connecting member 26 may also be fixed to the rear end portion of at least one of the inner shaft 22 and the outer shaft 25 by bonding or insert molding. The first connecting member 26 is formed, for example, of a resin, a metal, or the like. In addition, without being limited to the illustrated example, the outer shaft 25 and the first connecting member 26 may also be omitted. For example, the entire front shaft 21 may also be formed integrally.

[0037] The front end member 30 is a member that forms the front end portion of the barrel 20. The front end member 30 has the function of protecting the front end portion of the front shaft 21, the cover member 72, and the elastic member 76. The front end member 30 has a substantially truncated cone shape, and its outer diameter decreases as it moves forward. A front end opening 20a for the pen tip 13 to enter and exit is formed at the front end of the front end member 30. The front end member 30 is connected to the front shaft 21 by mounting the rear end portion of the front end member 30 on the front end portion of the front shaft 21. The front end member 30 is connected to the front shaft 21 by, for example, pressing, bonding, or screwing of the threaded portion.

[0038] The rear shaft 31 is a member having a substantially cylindrical shape disposed behind the front shaft 21. The rear shaft 31 includes an inner shaft 32, an outer shaft 35 disposed radially outside the inner shaft 32, a second connecting member 36, and a crown 38.

[0039] The inner shaft 32 is a member that houses the rear portion of the writing member 12. The inner shaft 32 is a member having a substantially cylindrical shape. The inner shaft 32 is formed of, for example, resin, metal, wood, or the like. On the inner peripheral surface of the inner shaft 32, a plurality of serrated cam teeth protruding forward and a groove portion formed between the cam teeth and extending in the axial direction da are formed.

[0040] The outer shaft 35 is a member visually confirmed by the user. Therefore, in consideration of designability and the like, the outer shaft 35 is formed of an appropriate material. For example, the outer shaft 35 can also be formed of resin, an elastomer, metal, wood, or the like. The second connecting member 36 is a member that constitutes the connecting portion with the front shaft 21. The second connecting member 36 is fixed to at least one of the front end portions of the inner shaft 32 and the outer shaft 35. For example, the second connecting member 36 can also be fixed to at least one of the front end portions of the inner shaft 32 and the outer shaft 35 by adhesion or insert molding. The second connecting member 36 is formed of, for example, resin, metal, or the like. In addition, not limited to the illustrated example, the inner shaft 32 and the outer shaft 35 can also be formed of one member. Further, the inner shaft 32, the outer shaft 35, and the second connecting member 36 can also be formed of one member. That is, the entire rear shaft 31 can also be integrally formed.

[0041] The insertion / removal mechanism 40 is a mechanism for alternately switching the writing tool 10 between a protruding state and a retracted state. The insertion / removal mechanism 40 of the present embodiment includes a pressing member 50, a rotary cam member 60, a first elastic member 42, and a second elastic member 44.

[0042] The first elastic member 42 is, for example, a coil spring. The first elastic member 42 is disposed in a compressed state between the first receiving portion 17 of the writing member 12 and the second receiving portion 28 of the shaft cylinder 20 (front shaft 21). The second receiving portion 28 is a stepped portion provided on the inner peripheral surface of the shaft cylinder 20 (front shaft 21) and includes a surface facing rearward. In the present embodiment, the first receiving portion 17 receives the elastic force from the first elastic member 42. Thus, the first elastic member 42 always applies a force to the writing member 12 relative to the shaft cylinder 20 toward the rear. In addition, the first elastic member 42 constitutes a part of the insertion / removal mechanism 40 and, as will be described later, constitutes a part of the sealing mechanism 70.

[0043] The pushing member 50 is a member intended to be operated by a user. The pushing member 50 includes an operation portion 52 and a diameter-expanded portion 54 located in front of the operation portion 52. The operation portion 52 is the part pressed by the user's finger or the like. The operation portion 52 protrudes rearward from the rear end of the shaft cylinder 20 (rear shaft 31). In the retracted state and the protruding state, the rear end of the operation portion 52 protrudes rearward from the rear end of the shaft cylinder 20. The diameter-expanded portion 54 has a radial dimension larger than the radial dimension of the operation portion 52. The inner diameter of the rear end portion of the shaft cylinder 20 is sized such that the operation portion 52 can pass through but the diameter-expanded portion 54 cannot pass through. Therefore, the pushing member 50 does not come off rearward from the rear end portion of the shaft cylinder 20.

[0044] Cam teeth protruding forward are formed at the front end of the diameter-expanded portion 54. In addition, a protruding portion engaged with a groove portion formed on the inner peripheral surface of the shaft cylinder 20 (rear shaft 31) is formed on the outer peripheral surface of the diameter-expanded portion 54. The pushing member 50 is configured to be movable in the axial direction da and non-rotatable in the circumferential direction in a state where the protruding portion is engaged with the groove portion of the shaft cylinder 20.

[0045] A hole portion 56 extending in the axial direction da is formed inside the pushing member 50. In the present embodiment, the hole portion 56 opens at the front end of the pushing member 50 and is closed at the rear end of the pushing member 50. An inward protruding portion 58 protruding toward the inner side in the radial direction is formed on the inner surface of the hole portion 56.

[0046] An O-ring 59 is disposed on the outer peripheral surface of the pushing member 50. The O-ring 59 is disposed in a groove portion formed to extend in a circumferential direction in a ring shape on the outer peripheral surface of the pushing member 50. In Figure 1 the example shown, the O-ring 59 is disposed between the operation portion 52 and the diameter-expanded portion 54 of the pushing member 50. The O-ring 59 has a function of sealing between the inner peripheral surface of the shaft cylinder 20 (rear shaft 31) and the outer peripheral surface of the pushing member 50 in the Figure 1 retracted state shown. The O-ring 59 is formed of an elastic material such as rubber, for example.

[0047] The rotary cam member 60 has a plurality of ridges extending in the axial direction da on its outer surface and engaged with the groove portion of the shaft cylinder 20. A cam surface inclined with respect to the axial direction da and the circumferential direction is formed at the rear end of the ridge. The cam surface is engaged with the cam teeth of the pushing member 50. The rotary cam member 60 has a rear protruding portion 62 protruding rearward along the axial direction da. A engaging portion 64 is provided at the rear end of the rear protruding portion 62. The engaging portion 64 is a protruding portion protruding toward the outer side in the radial direction from the rear protruding portion 62. The engaging portion 64 is engaged with the inward protruding portion 58 of the pushing member 50 to restrict the movement of the pushing member 50 and the rotary cam member 60 in the axial direction da.

[0048] A second elastic member 44 is disposed between the pressing member 50 and the rotary cam member 60. The second elastic member 44 is, for example, a coil spring. The second elastic member 44 is disposed within the shaft cylinder 20 behind the writing member 12. Specifically, the second elastic member 44 is disposed in a compressed state between the pressing member 50 and the rotary cam member 60. Therefore, the second elastic member 44 always applies a force to the pressing member 50 in the rearward direction relative to the rotary cam member 60. As a result, the pressing member 50 moves rearward relative to the rotary cam member 60, but the engagement of the engaging portion 64 of the rotary cam member 60 with the inward protrusion 58 of the pressing member 50 prevents the pressing member 50 from moving further rearward relative to the rotary cam member 60. In a state where the engaging portion 64 of the rotary cam member 60 is engaged with the inward protrusion 58 of the pressing member 50, the pressing member 50 is urged rearward by the second elastic member 44, thereby suppressing shaking of the pressing member 50.

[0049] The specific structures and operations of the groove portion of the shaft cylinder 20, the cam teeth and protrusions of the pressing member 50, and the ridges and cam surfaces of the rotary cam member 60 are well known, and thus detailed descriptions thereof are omitted. As an example, as their specific structures, the structure of the mechanism disclosed in Japanese Unexamined Patent Application Publication No. 2013-006281 can be used.

[0050] The writing instrument 10 of the present embodiment has a sealing mechanism 70 that seals the storage space S of the nib 13. Hereinafter, mainly with reference to Figure 3 this sealing mechanism 70 will be described. Figure 3 is a longitudinal sectional view showing an enlarged front portion of the writing instrument 10. The sealing mechanism 70 of the present embodiment is a mechanism that seals the front end of the storage space S. The sealing mechanism 70 includes a contact surface 22b of the shaft cylinder 20 (inner shaft 22), a lid member 72, an elastic member 76, and a pin 78.

[0051] The inner shaft 22 has an opening 22a through which the nib 13 can pass and a contact surface 22b surrounding the opening 22a. A lid member 72 is attached to the inner shaft 22. The elastic member 76 is a member that applies a force to the lid member 72 toward the contact surface 22b by its elastic force. The elastic member 76 is, for example, a torsion spring. One end of the elastic member 76 is attached to the lid member 72, and the other end is disposed in a recess 29 provided at the front end portion of the inner shaft 22. The pin 78 is disposed so as to extend in a direction perpendicular to the axial direction da. In Figure 3In the example shown, the pin 78 is inserted into a through-hole provided in the front end portion of the inner shaft 22. Further, the pin 78 is inserted into an annular portion provided at the base end portion of the lid member 72 and a loop portion of the elastic member 76. Thereby, the lid member 72 can rotate about the pin 78 to one side and the other side to contact or separate from the contact surface 22b. That is, the pin 78 is also the rotation axis of the lid member 72. Further, a clearance as a play may be formed between the annular portion provided at the base end portion of the lid member 72 and the outer peripheral surface of the pin 78. In this case, the pin 78 is also substantially the rotation axis of the lid member 72.

[0052] The lid member 72 closes the front end of the inner shaft 22 in the retracted state to seal the storage space S, and allows the tip 13 to project in the projected state. The lid member 72 has an opposed surface 74 that opposes the contact surface 22b in a state where the lid member 72 closes the opening 22a. The lid member 72 is urged by the elastic member 76 in the direction of sealing the storage space S of the tip 13. In the present embodiment, in the retracted state, the opposed surface 74 of the lid member 72 contacts the contact surface 22b of the inner shaft 22 by the elastic force of the elastic member 76 to close the opening 22a. Thereby, the storage space S of the tip 13 is sealed (see Figure 1 and Figure 3 ). In this case, drying of the ink in the tip 13 is suppressed. When changing from the retracted state to the projected state, the tip 13 moving forward presses the lid member 72 forward, whereby the lid member 72 opens and the tip 13 projects forward through the opening 22a and the front end opening 20a (see Figure 2 ). In this projected state, writing can be performed with the writing instrument 10.

[0053] In a conventional writing instrument having a sealing mechanism, as the writing member retracts, the lid member is closed, and then the writing member further retracts and is housed inside the barrel. At this time, after the lid member is closed and the writing member retracts, a negative pressure may sometimes be generated inside the storage space of the writing member. In this case, the ink housed inside the writing member may leak into the storage space via the tip.

[0054] In order to solve such a problem, the sealing mechanism 70 of the present embodiment includes a negative pressure suppression mechanism 80 that suppresses the pressure in the storage space S from becoming negative pressure. Here, negative pressure refers to a pressure lower than the pressure of the atmosphere in the environment where the writing instrument 10 is placed, that is, the atmospheric pressure. In the writing instrument 10 of the present embodiment in the immersed state, the pressure in the storage space S may not be exactly the same as the atmospheric pressure. In the present embodiment, a negative pressure is allowed such that the possibility of ink leaking into the storage space S through the nib 13 is small enough. That is, suppressing the pressure in the storage space S from becoming negative pressure includes not only the pressure in the storage space S becoming the same as the atmospheric pressure, but also the pressure in the storage space S becoming a negative pressure such that the possibility of ink leaking into the storage space S through the nib 13 is small enough.

[0055] The negative pressure suppression mechanism 80 of the present embodiment includes a closing delay mechanism 82 that delays the timing of the lid member 72 closing the opening 22a of the shaft cylinder 20 (inner shaft 22). In the negative pressure suppression mechanism 80 of the present embodiment, by using the closing delay mechanism 82 to delay the timing of the lid member 72 closing the opening 22a, the amount of retraction of the writing member 12 after the opening 22a is closed is reduced, thereby suppressing the pressure in the storage space S from becoming negative pressure.

[0056] The closing delay mechanism 82 of the present embodiment includes an elastic deformation portion 84 provided on the contact surface 22b or the opposing surface 74. When the elastic deformation portion 84 is provided on the contact surface 22b of the shaft cylinder 20 (inner shaft 22), the elastic deformation portion 84 deforms elastically when it contacts the opposing surface 74 of the lid member 72 and a pressing force of the elastic member 76 acts between the contact surface 22b and the opposing surface 74. Further, when the elastic deformation portion 84 is provided on the opposing surface 74, the elastic deformation portion 84 deforms elastically when it contacts the contact surface 22b and a pressing force of the elastic member 76 acts between the contact surface 22b and the opposing surface 74. In the present embodiment, when the pressing force of the elastic member 76 acts between the contact surface 22b and the opposing surface 74, the elastic deformation portion 84 deforms elastically, thereby delaying the timing of the lid member 72 contacting the contact surface 22b. As a result, the timing of the lid member 72 closing the opening 22a is delayed.

[0057] Refer to Figures 4 - 9 , an example of the elastic deformation portion 84 will be described. Figure 4 FIG. is a view showing an example of the negative pressure suppression mechanism 80 as viewed from the front. Figure 5 FIG. is a longitudinal sectional view showing an example of the negative pressure suppression mechanism 80, particularly showing a cross section corresponding to the V-V line of Figure 4 . Figure 6 FIG. is a view showing an enlarged view of the portion labeled VI of Figure 5 . Figure 7 FIG. is a view showing an enlarged view of the portion labeled VI ofFigure 6 A view showing an enlarged portion marked VII. Figure 8 is a longitudinal sectional view showing a part of the negative pressure suppression mechanism 80, particularly showing the section corresponding to the VIII-VIII line of Figure 4 . Figure 9 is Figure 8 A view showing an enlarged portion marked IX.

[0058] The elastic deformation portion 84 may also be a protruding portion 86 protruding from the contact surface 22b of the shaft cylinder 20 (inner shaft 22) or the opposing surface 74 of the lid member 72. In the present embodiment, the elastic deformation portion 84 is a protruding portion 86 protruding from the contact surface 22b. Additionally, without being limited thereto, the elastic deformation portion 84 may also be a protruding portion 86 protruding from the opposing surface 74.

[0059] The protruding portion 86 at least partially surrounds the opening 22a. The protruding portion 86 may only surround a part of the opening 22a or may surround the entire opening 22a. In Figure 4 the example shown, the protruding portion 86 is provided on a part of the side (lower side in Figure 4 ) close to the rotation axis (pin 78) of the lid member 72 around the opening 22a, and is not provided on a part of the side (upper side in Figure 4 ) far from the rotation axis of the lid member 72 around the opening 22a.

[0060] As Figures 5 - 7 shown, the height h (refer to Figure 7 ) of the protruding portion 86 in the direction perpendicular to the contact surface 22b becomes smaller as it is farther from the rotation axis of the lid member 72. The portion of the lid member 72 close to the rotation axis receives a greater pressing force from the lid member 72. Therefore, by increasing the height h of the protruding portion 86 of the portion of the lid member 72 close to the rotation axis, the timing of the lid member 72 closing the opening 22a can be effectively delayed.

[0061] The width W of the protruding portion 86 may also be 0.01 mm or more and 1.0 mm or less. Preferably, the width W of the protruding portion 86 may be 0.01 mm or more and 0.5 mm or less.

[0062] The rotation axis of the lid member 72 is located on the opposite side of the accommodation space S with respect to the extension surface 22c of the contact surface 22b. In Figure 5In the example shown, the rotation axis of the lid member 72 is located in front of the extension surface 22c of the contact surface 22b. In this case, the wall thickness of the inner shaft 22 of the portion behind the rotation axis (on the operation unit 52 side) can be sufficiently ensured. Thereby, while ensuring the strength of the inner shaft 22, the size of the recess 29 for accommodating the end portion of the elastic member 76 can be sufficiently ensured. Therefore, the strength of the front end portion of the inner shaft 22 can be improved, and the design freedom regarding the size, shape, etc. of the elastic member 76 can be increased. Thereby, deformation such as skew generated in the inner shaft 22 due to the elastic force of the elastic member 76 during opening and closing of the lid member 72 can be effectively suppressed.

[0063] In addition, the specific structure of the closing delay mechanism 82 is not limited to the structure having the elastic deformation portion 84 described above. As long as the closing delay mechanism 82 is a mechanism capable of delaying the timing at which the lid member 72 closes the opening portion 22a of the shaft cylinder 20 (inner shaft 22), it can be any mechanism. For example, the closing delay mechanism 82 can also be a mechanism having the following friction structure: when the lid member 72 is closed, the members come into contact with each other halfway to generate frictional force, and the timing at which the lid member 72 closes the opening portion 22a is delayed by using this frictional force. For example, the closing delay mechanism 82 can also be a mechanism having a damper structure other than the elastic deformation portion 84. As a damper structure other than the elastic deformation portion 84, for example, a damper structure using a viscous body, air, etc. can be cited.

[0064] On the other hand, according to the closing delay mechanism 82 having the elastic deformation portion 84 in the present embodiment, the closing delay mechanism 82 can be easily formed, and has excellent advantages such as stability of operation, cost required for formation, miniaturization of the closing delay mechanism 82, and durability.

[0065] Next, with reference to Figure 1 and Figure 2 the operation of the access mechanism 40 will be described.

[0066] In the retracted state ( Figure 1 ), when the user presses the push member 50 forward, the writing member 12 moves forward via the rotary cam member 60. When the writing member 12 moves forward, the nib 13 presses the lid member 72 forward against the elastic force of the elastic member 76, thereby opening the lid member 72. When the writing member 12 moves further forward, the nib 13 protrudes forward from the front end opening 20a. Even if the forward pressing of the push member 50 is released, the writing member 12 maintains the state in which the nib 13 protrudes forward from the front end opening 20a. Thereby, the writing instrument 10 changes from the retracted state to the protruding state.

[0067] In addition, in the protruding state ( Figure 2)When, under such circumstances, the user presses the pressing member 50 forward, the writing member 12 moves forward a small distance. When the forward pressing of the pressing member 50 is released, the writing member 12 moves backward by the elastic force of the first elastic member 42, and the nib 13 retracts from the front end opening 20a. When the writing member 12 moves further backward, the nib 13 is received in the receiving space S, and the lid member 72 closes the opening 22a of the shaft cylinder 20 (inner shaft 22) by the elastic force of the elastic member 76. Thus, the receiving space S is sealed. By sealing the receiving space S, the drying of the ink at the nib 13 is suppressed in the retracted state.

[0068] Next, with reference to Figures 5 - 7 and Figures 10 - 12 the operation of the sealing mechanism 70 will be described. In Figure 5 and Figures 10 - 12 the shaft cylinder 20 (inner shaft 22), lid member 72, elastic member 76, pin 78, and negative pressure suppressing mechanism 80 that constitute the sealing mechanism 70 are shown, and the illustration of other components constituting the writing instrument 10 is omitted.

[0069] When changing from the protruding state to the retracted state, the writing member 12 moves backward. When the nib 13 retracts into the receiving space S, the lid member 72 rotates and moves toward the contact surface 22b of the shaft cylinder 20 (inner shaft 22) by the elastic force of the elastic member 76. Thus, first, as Figures 5 - 7 shown, the opposing surface 74 of the lid member 72 contacts the front end of the portion of the protruding portion 86 closest to the rotation axis (pin 78) of the lid member 72.

[0070] The protruding portion 86 is configured to be elastically deformable by receiving the pressing force of the elastic member 76 via the lid member 72. When the protruding portion 86 is further pressed from the state shown in Figures 5 - 7 , as Figure 10 shown, the protruding portion 86 elastically deforms, and the opposing surface 74 of the lid member 72 approaches the contact surface 22b. When the protruding portion 86 is further pressed from the state shown in Figure 10 , as Figure 11 and Figure 12 shown, the protruding portion 86 further elastically deforms, and the opposing surface 74 of the lid member 72 contacts the contact surface 22b. Thus, the lid member 72 closes the opening 22a. In the example shown in Figure 12 , the protruding portion 86 elastically deforms in a manner of tilting inward toward the opening 22a.

[0071] In the present embodiment, when the pressing force of the elastic member 76 acts between the contact surface 22b and the opposing surface 74, the protruding portion 86 elastically deforms, whereby the timing of contact between the lid member 72 and the contact surface 22b can be delayed. Thus, the timing of the lid member 72 closing the opening 22a can be delayed.

[0072] The writing instrument 10 of the present embodiment includes: a shaft cylinder 20 having an opening 22a; a writing member 12 having a nib 13; an insertion / removal mechanism 40 for inserting and removing the nib 13 from the opening 22a; and a sealing mechanism 70 for sealing the storage space S of the nib 13 in the inserted state. The sealing mechanism 70 includes: a lid member 72 that contacts a contact surface 22b surrounding the opening 22a and can close the opening 22a; and a negative pressure suppression mechanism 80 that suppresses the pressure in the storage space S from becoming negative pressure.

[0073] According to such a writing instrument 10, when the writing instrument 10 changes from the Figure 2 protruding state shown to the Figure 1 inserted state shown, it is possible to suppress the writing member 12 from retreating after the lid member 72 closes the opening 22a and generating negative pressure inside the storage space S. Thus, it is possible to effectively suppress the ink stored inside the writing member 12 from leaking into the storage space S through the nib 13.

[0074] In the writing instrument 10 of the present embodiment, the negative pressure suppression mechanism 80 has a closing delay mechanism 82 that delays the timing of the lid member 72 closing the opening 22a.

[0075] According to such a writing instrument 10, by delaying the timing of the lid member 72 closing the opening 22a, the amount of retreat of the writing member 12 after the opening 22a is closed is reduced, and thus, it is possible to suppress the pressure in the storage space S from becoming negative pressure.

[0076] In the writing instrument 10 of the present embodiment, the lid member 72 has an opposing surface 74 opposing the contact surface 22b, and the closing delay mechanism 82 includes an elastic deformation portion 84 provided on the contact surface 22b or the opposing surface 74.

[0077] According to such a writing instrument 10, when the pressing force of the elastic member 76 acts between the contact surface 22b and the opposing surface 74, the elastic deformation portion 84 is elastically deformed, and thus, it is possible to delay the timing of the lid member 72 contacting the contact surface 22b. Thereby, it is possible to delay the timing of the lid member 72 closing the opening 22a.

[0078] In the writing instrument 10 of the present embodiment, the elastic deformation portion 84 is a protruding portion 86 protruding from the contact surface 22b or the opposing surface 74.

[0079] According to such a writing instrument 10, the elastic deformation portion 84 can be formed with a simple structure.

[0080] In the writing instrument 10 of the present embodiment, the protruding portion 86 at least partially surrounds the opening 22a.

[0081] According to such a writing instrument 10, the protrusion 86 can be effectively disposed between the contact surface 22b and the opposing surface 74.

[0082] In the writing instrument 10 of the present embodiment, the height h of the protrusion 86 in the direction perpendicular to the contact surface 22b or the opposing surface 74 becomes smaller as it is farther from the rotation axis of the lid member 72.

[0083] According to such a writing instrument 10, by increasing the height h of the protrusion 86 at the portion of the lid member 72 closer to the rotation axis (pin 78), the timing of the lid member 72 closing the opening 22a can be effectively delayed.

[0084] In the writing instrument 10 of the present embodiment, the rotation axis of the lid member 72 is located on the opposite side of the accommodation space S with respect to the extension surface 22c of the contact surface 22b.

[0085] According to such a writing instrument 10, the wall thickness of the inner shaft 22 at the portion rearward (operation portion 52 side) of the rotation axis can be sufficiently ensured. Thereby, while ensuring the strength of the inner shaft 22, the size of the recess 29 for accommodating the end portion of the elastic member 76 can be sufficiently ensured. Therefore, the strength of the front end portion of the inner shaft 22 can be improved, and the design freedom regarding the size, shape, etc. of the elastic member 76 can be improved. Thereby, deformation such as skew generated in the inner shaft 22 due to the elastic force of the elastic member 76 when the lid member 72 is opened and closed can be effectively suppressed.

Claims

1. A writing instrument having: a barrel having an opening; a writing member having a nib; an access mechanism for causing the nib to access and exit from the opening; and a sealing mechanism for sealing the storage space of the nib in a state where the nib is retracted, wherein the sealing mechanism has: a lid member that contacts a contact surface surrounding the opening to close the opening; and a negative pressure suppression mechanism that suppresses the pressure in the storage space from becoming negative.

2. The writing instrument according to claim 1, wherein the negative pressure suppression mechanism has a closing delay mechanism that delays the timing at which the lid member closes the opening.

3. The writing instrument according to claim 2, wherein the lid member has an opposing surface that opposes the contact surface, and the closing delay mechanism includes an elastically deformable portion provided on the contact surface or the opposing surface.

4. The writing instrument according to claim 3, wherein the elastically deformable portion is a protruding portion that protrudes from the contact surface or the opposing surface.

5. The writing instrument according to claim 4, wherein the protruding portion at least partially surrounds the opening.

6. The writing instrument according to claim 4 or 5, wherein the height of the protruding portion in a direction perpendicular to the contact surface or the opposing surface decreases as it moves farther away from the rotation axis of the lid member.

7. The writing instrument according to any one of claims 1 to 5, wherein the rotation axis of the lid member is located on the opposite side of the storage space with respect to the extension plane of the contact surface.

Images