Knock-type writing implement

Abstract

To provide a knock-type writing instrument capable of ensuring suppression of volatilization of ink from a pen tip at least before the start of use.SOLUTION: A knock-type writing instrument A is configured such that a refill 20 is stored in a barrel 10, ink is discharged from an ink storage member 18 stored in the refill 20 through a capillary phenomenon of a pen tip 30, and the pen tip 30 freely appears / disappears in / from the tip of the barrel 10 by a knock mechanism 70 provided to the barrel 10. In a state where the pen tip 30 is stored in the barrel 10, a through-hole 42 through which the pen tip 30 can slide back and forth is formed in a center. At least a seal member 40 is provided to the outer periphery in the vicinity of the tip side of the pen tip 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a knock-type writing instrument that can minimize the evaporation of ink from at least the pen tip. [Background technology]

[0002] BACKGROUND ART Conventionally, many writing implements such as knock-type pens have been known that are provided with an anti-drying structure that can prevent ink from volatilizing from the pen tip. For example, 1) a packing device for a knock-type fountain pen, characterized in that a ring-shaped packing made of rubber or soft synthetic resin is attached to the neck of a writing body inserted movably into a barrel, the packing being pressed against the outer periphery of the neck of the writing body and against the inner wall of the neck barrel, and rotating the neck of the writing body as the writing body moves (see, for example, Patent Document 1); 2) A retractable writing instrument having a writing body that can be retracted into a barrel and a sealing lid that seals the writing part of the writing body in conjunction with the back and forth movement of the writing body, characterized in that the sealing lid and the writing body are connected by a thread-like member, and the sealing lid and the thread-like member are molded integrally, and a sealing unit [reference numeral 4 (surface sealing portion: reference numeral 4f)] prevents the pen tip from drying out (see, for example, Patent Document 2). 3) A writing instrument in which the pen tip can be extended by operating an operating member provided on the barrel of the writing instrument, and the pen tip can be automatically retracted into the barrel by operating the operating member to open and close the pen tip, and an O-ring (reference numeral 17) is provided inside the barrel to further prevent the pen tip from drying out (see, for example, Patent Document 3). 4) A capless writing instrument (see, for example, Patent Document 4) is known which has a sealing chamber, which is a space provided within the writing instrument body for storing the tip writing part, a sealing lid with one end that can rotate freely to seal the front of the sealing chamber, sealing means for sealing the area behind the air hole of the writing body within the sealing chamber when stored, and connecting means having one end connected to the sealing lid and the other end connected to an interlocking member that receives a retracting force from the spring, and which has a drying prevention mechanism in which the writing body moves forward and backward within the writing instrument body and the tip writing part appears and disappears from the front end of the writing instrument body.

[0003] However, the knock-type writing instruments described in Patent Documents 1 to 4 above have a sealing mechanism that allows the pen tip to be freely extended and retracted using a sealing lid or the like to prevent it from drying out, and also have a sealing means that uses an O-ring or the like on the pen tip side, which has problems such as a complex structure that is costly and impairs design.Furthermore, there is no mechanism that reliably suppresses the evaporation of ink from the pen tip before use, and there is a strong demand for a knock-type writing instrument that can further improve the prevention of drying out of the pen tip. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Utility Model Registration No. 46-4971 (Scope of Claims, Figure 1, etc.) [Patent Document 2] JP 2003-191683 A (claims, Figures 1 and 3) [Patent Document 3] International Publication No. 2010 / 100800 (claims, Figures 1, 10, etc.) [Patent Document 4] Japanese Patent Application Laid-Open No. 1-281999 (Claims, Figure 1, etc.) Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above-mentioned problems of the conventional technology and aims to solve them, and aims to provide a knock-type writing instrument that can reliably suppress the evaporation of ink from the pen tip before use, and further to provide a knock-type writing instrument that has a structure that can suppress the evaporation of ink from the pen tip as much as possible even after use has begun. [Means for solving the problem]

[0006] As a result of extensive research into solving the above-mentioned conventional problems, the inventor discovered that a knock-type writing instrument having a refill housed within a barrel, a nib that ejects ink from an ink storage member housed in the refill by capillary action, and a knock mechanism provided in the barrel that allows the nib to be freely extended and retracted from the tip of the barrel by operating the knock mechanism, and when the nib is housed within the barrel, a through-hole is formed in the center that allows the nib to slide back and forth freely, and a specific structure is provided on the outer periphery near the tip of the nib, can be obtained, thereby completing the present invention.

[0007] In other words, the knock-type writing instrument of the present invention is a knock-type writing instrument that has a refill inside the barrel, the nib ejects ink from the ink storage member contained in the refill by capillary action, and the nib can be freely retracted from the tip of the barrel by a knock mechanism provided in the barrel, and is characterized in that when the nib is contained in the barrel, a through hole is formed in the center so that the nib can slide back and forth, and at least a sealing member is provided on the outer periphery near the tip of the nib. The sealing member preferably includes a sealing member located forward of the tip of the pen and capable of being removed by being pressed by the tip of the pen. It is preferable that the rear of the barrel is provided with a sealing mechanism that seals off air flow between the rear of the barrel and the outside of the writing instrument when not in use or when not being knocked, and that allows air to flow outside the writing instrument when being knocked, keeping the internal and external pressure constant and preventing ink from spraying out of the pen tip when not being knocked. It is preferable that a spiral groove be formed in a vapor suppression member that surrounds the outer periphery of the pen tip behind the sealing member. It is preferable that a spiral groove is formed on the inner surface of the seal member. It is preferable that a tip member be provided behind the pen tip of the refill, and that a spiral groove be formed on the outer circumferential surface of the tip member. The barrel is preferably formed with an inner wall against which the rear end face of the refill abuts, and a groove is preferably formed on the surface of the inner wall. It is preferable that the pen tip of the refill is separated from the ink storage member by the retraction / protrusion movement. The rear of the barrel is provided with a knock mechanism that allows the refill to be freely raised and lowered by pressing it, and the knock mechanism is preferably composed of a cam mechanism consisting of an operating unit and a rotor, and the rotor is preferably provided with a valve unit that opens due to the internal pressure inside the barrel. [Effects of the Invention]

[0008] According to the present invention, a knock-type writing instrument is provided that can reliably suppress the evaporation of ink from the pen tip before use, and further, a knock-type writing instrument is provided that can minimize the evaporation of ink from the pen tip even after use has begun. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. Both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention as claimed. [Brief explanation of the drawings]

[0009] [Figure 1] 1A to 1C are diagrams showing a state before the start of use of a knock-type writing instrument according to a first embodiment of the present invention, in which (a) is a plan view, (b) is a front view, and (c) is a vertical cross-sectional view as seen from the front. [Figure 2] 2A is a partially enlarged longitudinal cross-sectional view showing the main part of the knock-type writing implement of FIG. 1, FIG. 2B is a partially enlarged perspective view of a sealing member, and FIG. 2C is a partially enlarged longitudinal cross-sectional view of FIG. [Figure 3] 1A and 1B are diagrams showing an example of a refill with a fixed pen tip used in a knock-type writing instrument according to a first embodiment of the present invention, in which (a) is a perspective view, (b) is a vertical cross-sectional view from the front, and (c) is a partially enlarged vertical cross-sectional view of a key part. [Figure 4]4A to 4D are component diagrams of the evaporation suppression member fixed in the refill of FIG. 3, in which (a) is a perspective view, (b) is a plan view, (c) is a front view, and (d) is a vertical cross-sectional view. [Figure 5] 2A and 2B are diagrams showing the state of the knock-type writing instrument of FIG. 1 after the start of use and when not being knocked, where (a) is a plan view, (b) is a front view, (c) is a vertical cross-sectional view as seen from the front, and (d) is a partially enlarged vertical cross-sectional view of the pen tip portion. [Figure 6] 2A and 2B are drawings showing the state in which the pen tip is extended after the knock-type writing instrument of FIG. 1 has been knocked or the like to remove the sealing member, in which (a) is a partially enlarged longitudinal cross-sectional view showing the main part in section, (b) is a partially enlarged oblique view of the pen tip portion, and (c) is a partially enlarged longitudinal cross-sectional view of (b). [Figure 7] (a) is a partially enlarged longitudinal cross-sectional view showing the main parts of the knock-type writing instrument of Figure 6 after it has been knocked to extend the pen tip and then knocked again to return the pen tip to the barrel, (b) is a partially enlarged oblique view of the pen tip portion, and (c) is a partially enlarged longitudinal cross-sectional view of (b). [Figure 8] 10A and 10B are diagrams showing a state before the start of use of a knock-type writing instrument according to a second embodiment of the present invention, in which (a) is a plan view, (b) a front view, (c) a vertical cross-sectional view as seen from the front, and (d) a partially enlarged vertical cross-sectional view of the pen tip portion. [Figure 9] 10A and 10B are diagrams of a sealing member used in a knock-type writing instrument according to a second embodiment of the present invention, in which (a) is a perspective view from the left side, (b) is a front view, (c) is a right side view, and (d) is a vertical cross-sectional view as viewed from the front. [Figure 10] 9A and 9B are diagrams showing an example of a refill to which a pen tip is fixed for use in the knock-type writing instrument of FIG. 8, where (a) is a perspective view, (b) is a vertical cross-sectional view from the front, and (c) is a partially enlarged vertical cross-sectional view of a key part. [Figure 11] 10A and 10B are drawings showing a knock-type writing instrument according to a third embodiment of the present invention, in which (a) is a front view, (b) is a vertical cross-sectional view as seen from the front, and (c) is a partially enlarged vertical cross-sectional view showing the main parts cut away. [Figure 12] 12A and 12B are diagrams showing an example of a refill with a fixed pen tip used in the knock-type writing instrument of FIG. 11, in which (a) is a perspective view, (b) is a vertical cross-sectional view from the front, (c) is an enlarged perspective view of the tip of the pen tip, and (d) is a partially enlarged vertical cross-sectional view of the main part. [Figure 13] 12A and 12B are diagrams showing an example of a barrel used in the knock-type writing instrument of FIG. 11, in which (a) is a front view, (b) is a right side view, (c) is a vertical cross-sectional view, and (d) is an enlarged cross-sectional view taken along line DD in (c). [Figure 14] 12A and 12B are drawings showing the state of the knock-type writing instrument of FIG. 11 when not knocked, where (a) is a front view, (b) is a longitudinal sectional view, (c) is an enlarged sectional view of (b) taken along line XX, (d) is a partially enlarged longitudinal sectional view of (c), (e) is an enlarged sectional view of (b) taken along line YY, and (f) is a partially enlarged longitudinal sectional view of (e). [Figure 15] 12A and 12B are views showing the state of the knock-type writing instrument of FIG. 11 when knocked, in which (a) is a front view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view showing the air flow in the sealing member portion in a cross-sectional manner, (d) is a cross-sectional view showing the air flow in the lid member portion in a cross-sectional manner, and (e) is a partially enlarged longitudinal cross-sectional view showing the main parts cut away. [Figure 16] 10A and 10B are diagrams showing a state before the start of use of a knock-type writing instrument according to a fourth embodiment of the present invention, in which (a) is a front view, (b) is a vertical cross-sectional view as seen from the front, and (c) is a partially enlarged vertical cross-sectional view of the pen tip portion. [Figure 17] 17A and 17B are diagrams showing the state of the knock-type writing implement of FIG. 16 during writing, in which (a) is a front view, (b) is a vertical cross-sectional view as seen from the front, and (c) is a partially enlarged vertical cross-sectional view of the pen tip portion. [Figure 18] 17A and 17B are diagrams showing an example of a refill with a fixed pen tip used in the knock-type writing instrument of FIG. 16, where (a) is a perspective view, (b) is a vertical cross-sectional view from the front, and (c) is an enlarged vertical cross-sectional view of a key part. [Figure 19] 17A and 17B are component diagrams of the rotor of the knock mechanism of FIG. 16, in which (a) is a perspective view seen from the front side, (b) is a perspective view seen from the rear side, (c) is a front view, and (d) is a vertical cross-sectional view. [Figure 20] (a) is a longitudinal cross-sectional view showing the state in which the pen tip of the knock-type writing instrument of Figure 16 is stored inside the barrel (non-knock state), (b) is a partial longitudinal cross-sectional view showing the main parts on the rear end side when the internal pressure of the barrel increases in the non-knock state, and (c) is a partial longitudinal cross-sectional view showing the main parts on the rear end side in the knock state. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to the embodiments described below, but extends to the inventions set forth in the claims and their equivalents.

[0011] 1 to 7 are drawings showing a knock-type writing instrument according to a first embodiment of the present invention. As shown in Figures 1 to 7, the knock-type writing instrument of this first embodiment at least comprises a barrel 10 which forms the main body of the writing instrument, a refill 20 which houses an ink storage member 18 provided inside the barrel 10, a nib 30, a sealing member 40, and a knock mechanism 70, and the nib 30 ejects ink from the ink storage member 18 by capillary action, and the knock mechanism 70 allows the nib 30 to freely protrude and retract from the tip of the barrel 10. In this embodiment, as will be described later, at least a sealing member 40 is provided on the outer periphery near the tip of the pen tip 30, and when the pen tip 30 is housed in the barrel 10, a through hole 42 is formed in the center of the sealing member 40, allowing the pen tip 30 to slide freely back and forth.

[0012] The barrel 10, which forms the main body of the writing instrument, is formed from a thermoplastic resin or a thermosetting resin (hereinafter, each of the above resins will be simply referred to as "each resin") such as polyacetal resin, polyethylene resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, polyolefin resin, polyvinyl resin, polycarbonate resin, polyether resin, or polyphenylene resin, and is tapered toward the tip, with a sealing member 40 fixed to the opening 11 and a knock mechanism 70 attached to the opening 13 on the other rear end. The barrel 10 is provided with a refill 20 containing an ink storage member 18 therein.

[0013] The ink storage member 18 is impregnated with writing instrument ink such as water-based ink, oil-based ink, or thermochromic ink, and includes, for example, fiber bundles made of one or a combination of two or more types of natural fibers, animal hair fibers, polyacetal resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, polyolefin resin, polyvinyl resin, polycarbonate resin, polyether resin, polyphenylene resin, etc.; processed fiber bundles such as felt; and porous bodies such as sponge, resin particles, and sintered bodies. The ink storage member 18 is configured to be contained in a refill 20.

[0014] The composition of the ink for the writing instrument to be used is not particularly limited, and a suitable formulation such as water-based ink, oil-based ink, thermochromic ink, etc. can be used depending on the application of the writing instrument, etc. For example, in the case of an underline pen, etc., a fluorescent dye such as Basic Violet 11 or Basic Yellow 40 can be used in the ink, and a thermochromic microcapsule pigment, etc. can also be contained.

[0015] More preferably, by using an ink for a writing instrument that contains at least water, a water-soluble organic solvent, a colorant, and glyceryl glucoside as the composition, it is possible to achieve an excellent effect in suppressing drying of the pen tip, and the surface of the handwriting dries quickly, so that the handwriting does not spread even when rubbed, and it is possible to further prevent the handwriting from smearing even in a low-temperature environment.

[0016] The glyceryl glucoside used is either α-glyceryl glucoside, which is formed by condensation of glycerin and glucose via an α-bond, or β-glyceryl glucoside, which is formed by condensation via a β-bond. It may be an enzymatic reaction product obtained by treating a mixture of maltooligosaccharide and glycerin with α-glucosidase, or a product obtained by the condensation reaction of glycerin and glucose. Examples of glyceryl glucoside include α-glyceryl glucoside and β-glyceryl glucoside. α-glyceryl glucoside is more preferred. Specific examples of α-glyceryl glucoside include αGG and αGG-L (both manufactured by JST Corporation). The amount of these glyceryl glucosides added is preferably 0.5% by mass or more and 30.0% by mass or less of the total amount of the ink composition. These glyceryl glucosides may be used alone or in combination.

[0017] Examples of water that can be used in inks for writing instruments include tap water, groundwater, ion-exchanged water, pure water, and ultrapure water, and there is no particular limitation on the type of water that can be used.

[0018] The colorant that can be used in the ink for the writing instrument is not particularly limited, and dyes and pigments can be used.

[0019] The dye may be a water-soluble dye. Specific examples of the water-soluble dye include direct dyes, acid dyes, and basic dyes. These dyes may be used alone or in combination of two or more.

[0020] Specific examples of pigments include carbon black such as furnace black, contact black, thermal black, and acetylene black, black iron oxide, yellow iron oxide, red iron oxide, ultramarine, Prussian blue, cobalt blue, titanium yellow, turquoise, molybdate orange, titanium oxide, gold powder, silver powder, copper powder, aluminum powder, brass powder, tin powder, mica pigments, and CIPIGMENT RED. 2, 3, 5, 17, 22, 38, 41, 48:2, 48:3, 49, 50:1, 53:1, 57:1, 58:2, 60, 63:1, 63:2, 64:1, 88, 112, 122, 123 , 144, 146, 149, 166, 168, 170, 176, 177, 178, 179, 180, 185, 190, 194, 206, 207, 209, 216, 245, CIPIGMENT ORANGE 5, 10, 13, 16, 36, 40, 43, CIPIGMENT VIOLET Examples of pigments include 19, 23, 31, 33, 36, 38, 50, CIPIGMENT BLUE 2, 15, 15:1, 15:2, 15:3, 15:4, 15:5, 16, 17, 22, 25, 60, 66, CIPIGMENT BROWN 25, 26, CIPIGMENT YELLOW 1, 3, 12, 13, 24, 93, 94, 95, 97, 99, 108, 109, 110, 117, 120, 139, 153, 166, 167, 173, CIPIGMENT GREEN 7, 10, and 36. These pigments may be used alone or in combination. Furthermore, a pigment and a dye may be used in combination as the colorant.

[0021] When a pigment is used as the colorant, a dispersant can be used to stably disperse the pigment. Dispersants that can be used include conventionally used pigment dispersants, such as water-soluble resins or anionic or nonionic surfactants. The amount of these water-soluble resins and surfactants added is preferably 0.05% by mass or more and 20.0% by mass or less per 10.0% by mass of pigment. These water-soluble resins and surfactants can be used alone or in combination.

[0022] Pigment dispersions in which pigments are dispersed in aqueous media can also be used. Pigment dispersions can include inorganic pigments, organic pigments, fluorescent pigments, and the like, and these can be used alone or in combination. However, when colored resin particles are used as a colorant, the resin particles should be insoluble in organic solvents.

[0023] In addition to the colorants described above, colorless particles such as resin particles, wax particles, and resin emulsions can be used to adjust the color. Among these, oxidized polyethylene wax particles can be used to simultaneously suppress the offset of handwriting.

[0024] Regardless of whether the ink is a colorant or colorless particle, it is preferable to have a solids concentration of 25% by mass or more in the writing instrument ink, as this can prevent the ink from showing through to the back side. Furthermore, the use of oxidized polyethylene wax particles can prevent the ink from showing through to the back side even when the solids concentration in the writing instrument ink is 25% by mass or less, and the content of the oxidized polyethylene wax particles is preferably 0.1% by mass or more and 50.0% by mass or less, more preferably 0.5% by mass or more and 23.0% by mass or less, and most preferably 1.0% by mass or more and 15.0% by mass or less, based on the total amount of the ink composition.

[0025] The water-soluble organic solvent used in writing instrument inks refers to an organic solvent that can dissolve 10 g or more in 100 g of water. Among these water-soluble organic solvents, glycol ethers and water-soluble organic solvents with a cyclic structure are preferred, with water-soluble organic solvents with a cyclic structure being more preferred, from the viewpoints of pen tip permeability and suppression of pen tip drying. Furthermore, among these water-soluble organic solvents, the combined use of glycol ethers and / or water-soluble organic solvents with a cyclic structure and polyhydric alcohols is preferred because the interaction between glyceryl glucoside and the water-soluble organic solvent further improves the suppression of pen tip drying and pen tip permeability. The amount of these water-soluble organic solvents added is preferably 0.1% by mass or more and 50.0% by mass or less, and more preferably 5.0% by mass or more and 20.0% by mass or less, based on the total amount of the ink composition. These water-soluble organic solvents may be used alone or in combination.

[0026] The viscosity of the water-based ink for writing instruments is measured at a temperature of 25°C and a shear rate of 76.6 s -1 The surface tension is preferably 1.0 mPa·s or more and 20.0 mPa·s or less. The surface tension is preferably 30 to 60 mN / m.

[0027] In addition to the above components, additives such as lubricants, viscosity modifiers, antiseptics, antifungals, antirust agents, antifoaming agents, pH adjusters, etc. may be used in combination as needed. These additives may be used alone or in combination of two or more.

[0028] To produce a water-based ink for a writing instrument, the above-mentioned pigment and / or pigment dispersion, one or more colorants selected from dyes, water and / or an organic solvent, and a dispersant are thoroughly mixed and stirred in a disperser such as a homomixer, and then other additives such as a viscosity adjuster, a pH adjuster, a dye for adjusting color tone, a lubricant, etc. are added, and the mixture is further dissolved and mixed until uniform. However, depending on the circumstances, the mixed ink may be further dispersed in a disperser, or the obtained ink may be filtered or centrifuged to remove coarse particles and insoluble components.

[0029] 3(a) to 3(c), the refill 20 has a volatilization suppression member 35 that surrounds the outer periphery of the pen tip 30 and is fixed by fitting to the storage section 21a of the small-diameter cylindrical section 21 on the front side thereof, and the ink occluder 18 is stored in the storage section 22a of the expanded cylindrical section 22 that is connected to the small-diameter cylindrical section 21 and is expanded rearward of the expanded cylindrical section 21. In addition, a holding member 24 having a holding hole 23 that holds the rear side of the pen tip 30 is provided between the small-diameter cylindrical section 21 and the expanded cylindrical section 22, and the refill including these cylindrical sections 21, 22, etc. can be integrally molded from resin or the like. 4(a) to 4(d), the volatilization suppressing member 35 is cylindrical, has a through-hole 36 for securing the pen tip 30 therein, and has a spiral groove 37 formed on its outer periphery from one end to the other, with ends 37a and 37b of the spiral groove continuing to notches 36a and 36b at each end of the fixing hole 36. The spiral groove 37 may have a V-shaped or U-shaped cross section, for example. The length of the spiral groove is preferably at least twice the longitudinal (linear) length of the volatilization suppressing member 35 in order to reduce ink evaporation. Furthermore, by setting the groove shape, width, length, and the like of the spiral groove 37 within suitable predetermined ranges, ink evaporation and the like can be suppressed to a high degree.

[0030] 3(a) to 3(c), the pen tip 30 of this embodiment is shaped like a rod, with the tip side forming the writing portion 31. The central portion of this pen tip 30 is fixed to the fixing hole 36 of the evaporation suppression member 35, and the rear end portion 32 on the rear side is inserted into the central portion of the front side within the ink storage member 18, so that the ink stored in the ink storage member 18 is efficiently guided (supplied) to the writing portion 31 of the pen tip 30 by capillary force (capillary phenomenon). The pen tip 30 is made of a porous material, such as a parallel fiber bundle made of one or a combination of two or more types of natural fibers, animal hair fibers, polyacetal resin, polyethylene resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, polyolefin resin, polyvinyl resin, polycarbonate resin, polyether resin, polyphenylene resin, etc.; a fiber core made by processing fiber bundles such as felt or resin-processing these fiber bundles; a porous body (sintered core) made by sintering plastic powder such as thermoplastic resins such as polyolefin resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, etc.; or an extrusion-molded core.

[0031] Preferred pen tips 30 include fiber bundle tips, fiber tips, sintered tips, felt tips, sponge tips, and inorganic porous tips. These may also be coated fiber tips, the periphery of which is further coated with a resin film or the like. The porosity, size, hardness, and other properties of the pen tip 30 vary depending on the type of ink and writing implement. For example, a porosity of 30 to 60% is preferred. In the present invention, "porosity" is calculated as follows: First, a writing tip with a known mass and apparent volume is immersed in water, and after sufficient water absorption, the mass is measured after removal from the water. The volume of water absorbed into the writing tip is calculated from the measured mass. The volume of water is considered to be the same as the pore volume of the writing tip, and the porosity is calculated using the following formula: Porosity (unit: %) = (volume of water) / (apparent volume of nib 30) x 100

[0032] 2(a) to 2(c), the sealing member 40 is fixed by engagement, fitting, or the like to the tapered opening 11 at the tip of the barrel 10. The sealing member 40 has a through hole 42 formed in the center of a main body 41, through which the pen tip 30 can slide back and forth, and a sealing member 43 that can be removed at least by pressing the pen tip 30 or by a finger or the like is provided integrally on the outer periphery of the tip of the through hole 42, forward of the tip of the pen tip 30. An elastic engaging member 44 is connected to the outer periphery of the through hole 42 to be fixed to the circumferential engaging portion 12 of the opening 11. The sealing member 43 is provided integrally so as to close the outlet of the through-hole 42, and can be easily removed by pressing it when the pen tip 30 is knocked as described below or by a finger or the like; for example, the connecting portion 43a is made thin (ultra-thin), and before it falls off, the sealing member 40 including this connecting portion 43a and the sealing member 43 is configured to prevent volatilization of ink at the pen tip 30. The sealing member 43 can be easily removed from the main body 42 of the sealing member 40 by pressing the circumferential connecting portion 43a with the pen tip 30 or cutting it with a finger or the like. In order to ensure satisfactory sealing properties and ease of removal, materials that can be preferably used for the sealing member 40 include, in addition to the above-mentioned resins, thermoplastic elastomers such as styrene-based elastomers, vinyl chloride-based elastomers, olefin-based elastomers, polyester-based elastomers, polyamide-based elastomers, and urethane-based elastomers (hereinafter, each of the above elastomers will be simply referred to as the ``thermoplastic elastomers''), and synthetic rubbers such as nitrile butadiene rubber (NBR), silicone rubber, ethylene propylene rubber (EPDM), fluorosilicone rubber, fluororubber, urethane rubber, natural rubber, chloroprene rubber, butadiene rubber, and butyl rubber (hereinafter, each of the above synthetic rubbers will be referred to as the ``synthetic rubbers'').Furthermore, the sealing member 40 and the barrel 10 may be integrally formed by two-color molding (for example, two-color molding of the above-mentioned resins and thermoplastic elastomers).

[0033] In this embodiment, the pen tip 30 can slide back and forth in the through-hole 42 of the sealing member 40 by knocking, but there is a small gap X between the periphery 42a of the rear end of the through-hole 42 and the periphery of the pen tip 30 to suppress evaporation of ink and to perform efficient air replacement (to keep the internal and external pressure constant), specifically, the gap X is 0.02 to 1.0 mm, and in this embodiment it is 0.05 mm (see Figure 2(c)). A lid member 50 that seals the opening 20b at the rear end of the refill 20 is attached by fitting to the opening 20b. The lid member 50 has a fitting 51 that seals the opening 20b, and also has a cylindrical flange portion 52.

[0034] 2, 6, 7, etc., the knock mechanism 70 of this embodiment includes an inner tube 60 that is attached to the rear end opening 13 of the barrel tube 10 by screwing, a rotor 65 that is arranged within the inner tube 60 so as to be movable in the front-rear direction, and a knock body 66 that is an operating part that protrudes from the rear end within the inner tube 60 and is movable in the front-rear direction. Also, as shown in FIG. 2(a), the inner tube 60 includes a flange portion 61 that tightly contacts and seals with the L-shaped abutment surface 13a of the rear end opening 13 of the barrel tube 10, an inner tube portion 63 that has a threaded portion 62 on its outer circumferential surface on the front side of the flange portion 61, and an outer tube portion 64 on the rear side of the flange portion 61. Also, a tip end surface 63a of the inner tube portion 63 tightly contacts and seals with the abutment surface 53 of the flange portion 52 of the lid member 50 that seals the rear end opening 20b of the refill 20. In order to further improve the sealing ability (hermetic sealing) between the contacting surfaces that form the end faces, it is preferable to use the thermoplastic elastomers or synthetic rubbers mentioned above, in addition to the resins mentioned above, for the cover member 50 and the inner tube 60.

[0035] The knock mechanism 70 of this embodiment allows the refill 20 to be raised and lowered by a pressing operation, and is equipped with a known mechanism (rotary cam mechanism) having a knock body 66 serving as an operating part, a rotor 65, and an outer cam (not shown) provided on the inner periphery of the inner cylinder 60. This knock mechanism, together with the refill 20, is urged rearward by an elastic member 71 made of a coil-shaped spring member held between the retaining members 14, 14... and retaining step portions 14a, 14a... provided at predetermined intervals in the vertical direction on the inner periphery of the front part of the barrel 10, and the mounting step portion 20a provided on the outer periphery on the front side of the refill 20. The knock operation is performed by pressing the knock body 66 forward. When a knocking operation is performed, the rotor 65 is pressed forward by the movement of the knock body 66, the rotor 65 engages with the front end face of the outer cam (not shown) of the inner tube 60, the refill 20 moves forward, and the nib 30 fixed to the evaporation suppression member 35 inside the refill 20 comes out from the exit of the through-hole 42 of the sealing member 40, entering a writing state (see Figure 6). When a knocking operation is performed again after writing, etc., the above-mentioned engagement state is released, the refill 20 moves backward, and the nib 30 returns to its original position, etc. (see Figure 7, etc.). Furthermore, in this embodiment, it is preferable that the stroke T of the knock mechanism 70 is set to 2.0 to 15.0 mm, as shown in Fig. 7(a). By setting the stroke T in this range, the knock mechanism 70 becomes more efficient and evaporation can be suppressed.

[0036] In the knock-type writing instrument A configured as described above, the sealing member 43 of the sealing member 40 is designed to be removable when the initial knock operation (first knock operation) is performed as the knock operation. That is, as shown in FIGS. 1 and 2, the seal member 40, including the sealing member 43, reliably prevents ink from volatilizing from the nib 30 at the tip of the barrel 10 before use. As described above, the sealing member 43 can be removed by pressing the nib 30 (to enter the writing state by the knock operation) or by tearing it off with a finger or the like, so that the sealed state can be easily released, and the writing state can be entered by this release (see FIG. 6). Even after the initial knock operation, only the nib 30 is exposed at the tip of the barrel 10, so the amount of ink volatilizing from the nib 30 can be suppressed.

[0037] Furthermore, in this embodiment, in addition to the above embodiment, or as an independent embodiment, a sealing mechanism is provided at the rear of the barrel 10 to seal off air communication between the rear of the barrel 10 and the outside of the writing instrument when the writing instrument is not in use or when not being clicked, and to allow air to circulate outside the writing instrument when the writing instrument is clicked, thereby maintaining a constant internal and external pressure and preventing ink from spraying out of the nib 30 when the writing instrument is not being clicked. That is, in this embodiment, the sealing mechanism prevents ink from volatilizing from the nib 30 when the writing instrument is not in use by the sealing member 43 of the sealing member 40. Also, as shown in FIG. 2(a), when the writing instrument is not in use (including when not being clicked), the flange 61 of the inner tube 60 and the abutting surface 13a of the rear end opening 13 are tightly sealed at the rear end side of the barrel 10, and the tip surface 63a of the inner tube portion 63 and the rear end abutting surface 53 of the cover member 50 are tightly sealed, so that ink volatilization from the rear end of the barrel 10 is also suppressed. Furthermore, when the knocking operation is performed when the pen is not in use or is not being knocked, air is taken in through the gap X between the nib 30 and the sealing member 40, as shown in Figure 6(c), and as shown in Figure 6(a), the taken in air passes through the space (gap) between the barrel 10 and the refill 20 and the gap between the inner tube 63 and the rotor 65 and is discharged to the outside of the writing instrument, making the internal and external pressure constant and preventing ink from spraying out of the nib 30 due to an increase in internal pressure inside the barrel 10.

[0038] Furthermore, in the above embodiment, if a spiral groove 37 is formed on the outer periphery of the volatilization suppression member 35 that surrounds the outer periphery of the nib 30 fixed to the storage chamber 22 of the refill 20 behind the sealing member 40 as described above and as shown in Figures 3 and 4, the volatilization of ink from the ink storage member 18 in the refill 20 occurs through the spiral groove 37, which is longer than a linear gap (groove) and can also suppress the volatilization of ink from the refill 20 alone. Therefore, in the knock-type writing instrument of this embodiment, the sealing member 40 having the sealing member 46 and the spiral groove 37 of the volatilization suppression member 35 provide a knock-type writing instrument that can reliably suppress the volatilization of ink from the nib before use. This will be done.

[0039] 8 to 20 are drawings showing other embodiments of the knock-type writing instrument of the present invention. Note that, in the following embodiments, when the same configuration and function as the writing instrument A of the first embodiment are present, the same reference numerals are used in the drawings and the like, and the description thereof will be omitted. Figures 8 to 10 are drawings of a knock-type writing instrument B of this second embodiment, where Figure 8 is a drawing showing the state before use, Figure 9 is a drawing of a sealing member used in the knock-type writing instrument, and Figure 10 is a drawing showing an example of a refill with a fixed pen tip used in the knock-type writing instrument. The knock-type writing instrument B of the second embodiment differs from the knock-type writing instrument A of the first embodiment and the like in that it has an anti-slip portion 10a formed with multiple grooves formed at predetermined intervals around the circumference near the grip portion on the outer periphery of the barrel 10, that it has a seal member 45 without a sealing member that is fixed by fitting or the like to the opening 11 of the barrel 10 instead of the seal member 40, that the shape of the refill 20 is different, that it has a clip portion 75 on the outside of the inner barrel 60, and that the sealing mechanism on the rear side is slightly different. The knock mechanism 70 functions in the same way as the knock-type writing instrument A of the first embodiment.

[0040] In this knock-type writing instrument B, as shown in Figures 9(a) to (d), the sealing member 45 has a through hole 46 formed in the center, and a spiral groove portion 47 similar to the spiral groove portion formed in the above-mentioned evaporation suppression member 35 is formed on the inner circumference of the through hole 46, and the small diameter portion 45a, which has a smaller outer diameter on the front side, is fixed into the opening 11 of the barrel 10 by fitting or the like. As shown in Figures 10(a) to (c), the refill 20 of this embodiment differs from the refill of the first embodiment in that it does not have the evaporation suppression member 35 of the first embodiment described above, and the front side is a front fixed holding portion 21c having a fixing portion 21b that fixes the pen tip 30.

[0041] In the knock-type writing instrument B configured in this manner, similar to the knock-type writing instrument A of the first embodiment described above, the pen tip 30 ejects ink from the ink storage member 18 by capillary action, and the knock mechanism 70 allows the pen tip 30 to freely protrude and retract from the tip of the barrel 10. In this embodiment, a through hole 46 is formed in the center of the sealing member 45, allowing the pen tip 30 to slide back and forth, and a spiral groove 47 is formed on the inner periphery of the through hole 46 of the sealing member 45. Since ink volatilization from the sealing member 45 occurs through the spiral groove 47, which is longer than a linear gap (groove), it is possible to suppress ink volatilization. Furthermore, by setting the groove shape, width, length, etc. of the spiral groove 47 within a suitable predetermined range, it is possible to highly effectively suppress ink volatilization while maintaining constant internal and external pressure due to air circulation. Therefore, in the knock-type writing instrument B of this embodiment, the spiral groove 47 of the sealing member 45 provides a knock-type writing instrument that can reliably suppress the evaporation of ink from the pen tip 30. Furthermore, in this embodiment, the sealing mechanism on the rear side of the barrel 10 is sealed when the abutment surface 65a of the rotor 65 and the tip surface 63a of the inner barrel portion 63 are in contact with each other when the pen is not in use or when not being knocked, and this abutment surface is opened when the pen is knocked. Therefore, similar to the first embodiment, the rear of the barrel 10 is sealed to prevent air from passing between the rear of the barrel 10 and the outside of the writing instrument when the pen is not in use or when not being knocked, and air passes through to the outside of the writing instrument when the pen is knocked, keeping the internal and external pressure constant and preventing the pen tip from opening when the pen is not being knocked. It is equipped with a sealing mechanism that prevents ink from spraying out from 30, and also suppresses ink evaporation from the rear end of the barrel 10. When the knocking operation is performed while not knocking, air is taken in from the spiral groove 47 of the nib 30 and the sealing member 45, and the taken in air passes through the space (gap) between the barrel 10 and the refill 20, and the gap between the inner tube 63 and the rotor 65 and is discharged outside the writing instrument, making the internal and external pressure constant and preventing ink from spraying out from the nib 30 due to an increase in internal pressure inside the barrel 10.

[0042] 11 to 15 are drawings showing an example of a knock-type writing instrument according to the third embodiment, a refill to which a pen tip used in this embodiment is fixed, a barrel, and states when not knocking and when knocking, respectively. As shown in Figures 11 to 15, the knock-type writing instrument C of this third embodiment differs from the knock-type writing instrument B of the second embodiment in that a tip member 25 is provided at the tip side of the refill 20 to which the rear of the nib 30 is fixed, and a spiral groove 26 is formed on the outer peripheral surface of the front part of this tip member 25, the tip member 25 to which the tip side of the nib 30 is fixed can slide freely back and forth in a through hole 46 having a spiral groove portion 47 on the inner circumference of a sealing member 45, and the barrel 10 is formed with an inner wall 15 against which the abutment surface 53 of the lid member 50 fixed to the rear end side of the refill 20 abuts, and a spiral groove 16 is formed on the inner peripheral surface of the rear side of the inner wall 15.

[0043] 14 and 15 are explanatory diagrams illustrating the states of the knock-type writing instrument of the third embodiment when not being knocked and when being knocked. In this embodiment, the sealing mechanism on the rear side of the barrel 10 is such that, when not in use or when not being knocked, the abutment surface 53 of the cover member 50 abuts against the inner wall 15 of the barrel 10 to seal the instrument, as shown in Fig. 14(b), and when knocked, the abutment surface 53 of the cover member 50 and the inner wall 15 of the barrel 10 open, as shown in Fig. 15(b).

[0044] In the knock-type writing instrument C configured in this manner, similar to the knock-type writing instrument B of the second embodiment described above, the pen tip 30 ejects ink from the ink storage member 18 by capillary action, and the knock mechanism 70 allows the pen tip 30 to freely protrude and retract from the tip of the barrel 10. In this embodiment, a through hole 46 is formed in the center of the sealing member 45, allowing the pen tip 30 to slide back and forth, and a spiral groove 47 is formed on the inner periphery of the through hole 46 in the sealing member 45. A spiral groove 26 is also formed on the tip side of the tip member 25, so that ink volatilization and the like occurs only from the exposed part of the pen tip 30, thereby suppressing ink volatilization. Furthermore, by setting the groove shape, width, length, etc. of the spiral groove 47 and the spiral groove 26 of the tip member 25 within suitable predetermined ranges, it is possible to highly effectively suppress ink volatilization and maintain constant internal and external pressure due to air circulation. Therefore, in the knock-type writing instrument C of this embodiment, the spiral groove 47 of the sealing member 45 and the spiral groove 26 of the tip member 25 provide a knock-type writing instrument that can reliably suppress the evaporation of ink from the pen tip 30. Furthermore, in this embodiment, the sealing mechanism on the rear side of the barrel 10 is sealed when the abutment surface 53 of the cover member 50 abuts against the inner wall 15 of the barrel 10 when the pen is not in use or when not being knocked, and this abutment surface is opened when the pen is knocked. Therefore, as with the first and second embodiments, the rear of the barrel 10 seals the air circulation between the rear of the barrel 10 and the outside of the writing instrument when the pen is not in use or when not being knocked, and when the pen is knocked, air flows to the outside of the writing instrument, keeping the internal and external pressure constant and preventing ink from spraying out of the pen tip 30 when the pen is not being knocked. The pen is equipped with a sealing mechanism that prevents ink from evaporating from the rear end of the barrel 10, and when the knocking operation is performed from a non-knocking state, air is taken in through the spiral groove 47 of the nib 30 and the sealing member 45, and the spiral groove 26 of the tip member 25, as shown in Figures 15(b) to (e).The taken in air passes through the space (gap) between the barrel 10 and the refill 20, and the gap between the barrel 10 and the rotor 65, and is discharged to the outside of the writing instrument, making the internal and external pressures constant and preventing ink from spraying out of the nib 30 due to an increase in internal pressure inside the barrel 10.

[0045] Figures 16 to 20 are drawings respectively showing the state of the knock-type writing instrument of this fourth embodiment before use, the state during writing, an example of a refill with the nib to be used fixed thereto, the rotor of the knock mechanism, and the state in which the nib is stored in the barrel (non-knock state). The knock-type writing instrument D of this fourth embodiment differs from the writing instrument B of the second embodiment described above in that the nib 30 of the refill 20 is configured to move away from the ink storage member 18 by extending and retracting, and the rear of the barrel 10 is provided with a knock mechanism that allows the refill 20 to be freely extended and retracted by pressing, the knock mechanism being composed of a cam mechanism consisting of a knock body that serves as the operating part and a rotor, and the rotor is provided with a valve member that opens due to the internal pressure inside the barrel.

[0046] Specifically, in the knock-type writing instrument D of the fourth embodiment, a tip fixing member 27 for fixing the nib 30 having a cushion member is attached to the small-diameter tubular portion 21 of the refill 20 so that the nib 30 of the refill 20 is separated from the ink storage member 18 by the retraction and protrusion action. As shown in Figures 18(a) to 18(c), this tip fixing member 27 has a main body portion 27a fixed to the small-diameter tubular portion 21 of the refill 20 by fitting or the like, and a fixing portion 27b for fixing the nib 30 to the tip, and also has a cushion member 27c made of a spring portion integrally formed between the main body portion 27a and the fixing portion 27b. In addition, a sealing member 48 has a through-hole 49 in its center, and is fixed to the opening 11 of the barrel tube 10 by fitting or the like. In this embodiment, the knock mechanism 70, which allows the refill 20 located at the rear of the barrel 10 to be raised and lowered by pressing, is composed of a cam mechanism consisting of a knock body 66 which serves as the operating part and a rotor 65, and the rotor 65 is fitted with a valve member 68 which opens due to the internal pressure inside the barrel 10.

[0047] 16, 17, and 19, rotor 65 is composed of small-diameter portion 65a that is inserted into knock body 66, which serves as the operating part, and is used for centering, and large-diameter portion 65b that is located in front of small-diameter portion 65a, with large-diameter portion 65b having a larger diameter than small-diameter portion 65a, and large-diameter portion 65b and small-diameter portion 65a being cylindrical. Cam portions 65c, 65c... that have shapes complementary to cam portions (not shown) of knock body 66, which serves as the operating part, are formed on the rear end surface of large-diameter portion 65b to form a cam mechanism, and a concave flange portion 65d that abuts against cover member 50 is formed on the front end surface. A valve member 68 is attached to the outer peripheral surface and end surface of the small-diameter portion 65a of the rotor 65 so as to close the opening. As shown in FIGS. 19(a) to 19(d), the valve member 68 is an elastic body integrally formed with a wristwatch-shaped valve portion 68a, a ring-shaped portion 68b spaced from the valve portion 68a, and a continuous portion 68c connecting the valve portion 68a and the ring-shaped portion 68b in the front-rear direction. When the valve portion 68 is attached to the rotor 65, the valve portion 68a closes the rear-end opening of the small-diameter portion 65a, the ring-shaped portion 68b fits into the circumferential groove of the small-diameter portion 65a, and the continuous portion 68c fits into the vertical groove, providing a tight fit. The valve member 68 can be molded using, for example, the synthetic rubbers and thermoplastic elastomers described above. Alternatively, the rotor 65 including the valve member 68 can be integrally molded using two-color molding. In this embodiment, the rotor 65 is made of polyacetal, and the valve member 68 is made of a styrene-based elastomer, and they are molded by two-color molding.

[0048] The knock mechanism in this embodiment operates by pressing the knock body 66, which serves as an operating part, forward, and moving the rotor 65 together with the knock body 66 forward within the inner cylinder 60 to a predetermined position. Figure 16 shows the state before the start of use of the knock-type writing instrument of the fourth embodiment, in which the tip of tip fixing member 27 to which nib 30 attached to the tip side of refill 20 is fixed is inserted into through-hole 49 of sealing member 48, the rear end side of nib 30 is separated from ink storage member 18, ink is not being supplied, and no ink is volatilizing from nib 30. When knock body 66, which serves as the operating part, is pressed forward by knocking operation from this state, rotor 65 moves forward to a predetermined position, as shown in Figure 17. At this time, the tip fixing member 27 moves forward, but the step 27b1 of the fixing portion 27b abuts against the outer peripheral surface 48a of the rear end of the sealing member 48, preventing the movement, and the cushion member 27c, which is made up of a spring, contracts in diameter (shrinks) due to its elastic force, so that the rear end 32 of the nib 30 is inserted into the ink storage member 18, and the nib 30 comes out of the outlet of the through-hole 48 of the sealing member 47, and ink in the ink storage member 18 is supplied to the writing portion 31 of the nib 30 by capillary force, thereby achieving a writing state. Thereafter, to return to the non-writing state, a knock operation (pressing the knock body 66) is performed, and the cam mechanism, including the rotor 65, releases the lock of the cam mechanism, causing the rotor 65 to rotate. After that, when the force applied to the operating portion is released, the urging force of the elastic member 71 moves the rotor 65 further rearward, and the knock-type writing instrument D returns to the non-writing state, as shown in Figure 16.

[0049] In this embodiment, when writing, the rear end 32 of the pen tip 30 is inserted into the ink storage member 18 and ink is supplied to the writing portion 31 of the pen tip 30, but when not writing, the rear end of the pen tip 30 is structured to be separated (decoupled) from the ink supply member 18, which, together with the sealing member 48, reliably suppresses the evaporation of ink from the ink storage member 18.In addition, even if the internal pressure inside the barrel 10 increases, the rear end of the pen tip 30 is separated (decoupled) from the ink supply member 18, so ink will not spray out.

[0050] In the knock-type writing instrument D of this embodiment, what happens when the internal pressure in the barrel 10 increases, and how air is taken in when knocking is performed will be described in further detail with reference to FIG. (a) is a longitudinal cross-sectional view showing the state in which the pen tip of the knock-type writing instrument of Figure 16 is stored inside the barrel (non-knock state), (b) is a partial longitudinal cross-sectional view showing the main parts on the rear end side when the internal pressure of the barrel increases in the non-knock state, and (c) is a partial longitudinal cross-sectional view showing the main parts on the rear end side in the knock state. In the non-knock state of the knock-type writing instrument D of this embodiment, if the internal pressure of the barrel 10 increases due to fluctuations in the outside air temperature, as shown in Figure 20(b), when air passes through the inside of the rotor 65 and reaches the inner surface of the valve portion 68a of the valve member 68, the air pressure causes the continuous portion 68c of the valve member 68 to elastically deform and stretch, causing the valve portion 68a to float from the opening, creating a gap and opening the valve, and the air that has escaped from the rotor 65 is discharged outside the writing instrument D through the gap between the outer tube portion 64 and the knock body 66.

[0051] Furthermore, when the knock-type writing instrument D of this embodiment is knocked, the refill 20 moves forward, and as shown in Figure 20(c), the abutment surface 65a of the rotor 65 and the tip surface 63a of the inner tube portion 63 are opened, so that air outside the writing instrument enters through the gap between the knock body 66 and the inner tube 60 and is taken into the barrel tube 10, making the internal and external pressure constant. The knock-type writing instrument D of this embodiment is equipped with a mechanism for taking in air at the rear end of the barrel 10 and purging when the internal pressure of the barrel 10 increases, and this can be done efficiently with a simple structure.

[0052] The knock-type writing instrument of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the technical concept of the present invention. The structure in which a valve member 68 is attached to the rotor 65 in the knock-type writing instrument D of the above embodiment may be applied to each rotor 65 of the writing instruments A to C of the above first to third embodiments, so that air can be purged from the rear end side when the internal pressure inside the barrel 10 increases.

[0053] Furthermore, in the knock-type writing instruments A to D of the above-described embodiments, the pen tip 30 is a rod-shaped pen tip, but it may also be bullet-shaped. Furthermore, in each of the above embodiments, ink for writing instruments (water-based ink, oil-based ink, thermochromic ink) was described, but the liquid may also be liquid materials such as liquid cosmetics, liquid medicines, coating liquids, and correction fluids. [Example]

[0054] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0055] Example 1 A knock-type writing instrument having the following configuration and a pen tip conforming to Figures 1 to 7, and ink for the writing instrument having the following composition were used. The dimensions of the pen tip and writing instrument are as shown below.

[0056] (Writing instrument configuration) Shaft tube 10: Polypropylene, length 127 mm, central inner diameter 9 mm, outer diameter 11 mm Ink storage material: PET fiber bundle, porosity 85%, φ6 x 80 mm Refill 20: Made of polypropylene, length 97 mm, central inner diameter 6 mm Nib 30: Polyacetal, φ1.0 x 30mm Volatilization suppression member 35: Made of polyacetal, spiral groove: U-shaped groove, width 0.3 mm, number of spirals: 8 (around) Seal member 40: Made of thermoplastic elastomer, the barrel 10 and the seal member 40 are two-color molded Gap X: 0.05mm, Stroke T: 6mm The cover member 50, inner cylinder 60, rotor 65, and knock body 66 are all made of polypropylene. Elastic member 71: Stainless steel

[0057] (Ink composition for writing instruments, ink color: black) As the ink for the writing instrument, ink having the following composition (total 100% by mass) was used. Surfactant: Megafac F410 (fluorine-based anionic surfactant, perfluoroalkyl group-containing carboxylate, manufactured by DIC Corporation) 1% by mass Antifungal agent: Benzisothiazolin-3-one 0.2% by mass Glyceryl glucoside aqueous solution: αGG (high-concentration α-glyceryl glucoside aqueous solution, α-glyceryl glucoside 60% aqueous solution, manufactured by JTS Co., Ltd.) 3% by mass Pigment water dispersion: FUJI SP BLACK 8041 (black pigment water dispersion, solid content 20%, manufactured by Fuji Pigment Co., Ltd.) 20% by mass Water-soluble organic solvent: glycerin 5% by mass Water-soluble organic solvent: ethylene glycol 5% by mass Water (solvent): Ion-exchanged water 65.8% by mass Viscosity (25°C): 3.6 mPa·s (Complate type viscometer, TOKIMEC, TV-20) Surface tension (25°C): 40 mN / m (automatic surface tensiometer, Kyowa Interface Science Co., Ltd., DY-300)

[0058] In the knock-type writing instrument A equipped with the writing instrument ink having the above-described configuration, when the initial knock operation (first knock operation) was performed in the state shown in Figures 1 and 2 after manufacture, the pen tip 30 broke through the sealing member 43 of the sealing member 40 and came out. The sealing member 43 was connected to the sealing member 40 in a state where it looked like it might come off, but it was confirmed that it could be easily removed by pinching it with the fingers. It was confirmed that the sealing member 43 of the sealing member 40 can be easily removed by pressing the pen tip 30 (to enter the writing state by knocking) and / or by tearing it off with fingers, etc., and this removal allowed the pen to enter the writing state (see Figure 6). Furthermore, it was confirmed by sensory evaluation that the sealing mechanism provided on the rear end side of the barrel 10 prevents ink from volatilizing from the rear end of the barrel 10. [Industrial Applicability]

[0059] The present invention provides a knock-type writing instrument that can reliably suppress the evaporation of ink from the pen tip at least until the start of use. [Explanation of symbols]

[0060] 10 shaft cylinder 18 Ink storage member 20 Refill 30 nibs 35 Volatilization suppression material 40 sealing material 43 Sealing member 50 Lid member 60 Inner cylinder 65 rotor 66 Knock Body 70 Knock mechanism

Claims

1. A knock-type writing instrument having a refill inside the barrel, wherein the nib ejects ink from an ink storage member contained in the refill by capillary action, and wherein the nib can be freely retracted from the tip of the barrel by a knock mechanism provided in the barrel, wherein when the nib is contained within the barrel, a through-hole is formed in the center to allow the nib to slide back and forth, and wherein at least a sealing member is provided on the outer periphery near the tip of the nib, and wherein the rear of the barrel is provided with a sealing mechanism that seals off air circulation between the rear of the barrel and the outside of the writing instrument when not in use or when not being knocked, and allows air to circulate outside the writing instrument when knocked, maintaining constant internal and external pressure and preventing ink from spraying out of the nib when not being knocked, and wherein the ink storage member contains an ink composition for a writing instrument comprising at least water, a water-soluble organic solvent, a colorant, and glyceryl glucoside.

2. A knock-type writing instrument as described in Claim 1, characterized in that the amount of glyceryl glucoside added to the ink composition for the writing instrument is 0.5 mass % or more and 30.0 mass % or less relative to the total amount of the ink composition.

3. A knock-type writing instrument as described in claim 1 or 2, characterized in that the ink composition for the writing instrument uses oxidized polyethylene wax particles, and the content of the oxidized polyethylene wax particles is 0.1 mass % or more and 50.0 mass % or less relative to the total amount of the ink composition.

4. A knock-type writing instrument described in any one of claims 1 to 3, characterized in that the ink composition for the writing instrument uses a combination of a glycol ether and / or a water-soluble organic solvent having a cyclic structure that can dissolve 10 g or more in 100 g of water, and a polyhydric alcohol.

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