Ballpoint pen refills and ballpoint pens

Abstract

To provide a ballpoint pen refill which secures sufficient ball holding force while forming a receiving seat for a ball and a pressing member in the tip direction as a single member, and at the same time, enables drawing line expression like a writing brush.SOLUTION: Provided is a ballpoint pen refill, including a synthetic resin ink storage tube that stores ink inside, a synthetic resin ball holder mounted to the tip of the ink storage tube, a ball pressing rod mounted inside the ball holder, and a writing ball housed in the tip of the ball holder and having a rear end side held by the ball pressing rod. The ball pressing rod includes a fixed portion fixed to the ball holder, a movable portion that can slide back and forth with respect to the ball holder, a compression portion that connects the fixed portion and the movable portion, and a retraction restricting portion that protrudes from the tip of the fixed portion and has a clearance between it and the rear end of the compression portion.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a ballpoint pen refill and a ballpoint pen. [Background technology]

[0002] Patent Document 1 discloses a ballpoint pen that can draw thick or thin lines depending on the writing angle using the action of the outer casing. Patent Document 2 discloses a ballpoint pen that uses a resin ball seat and is fitted with a metal cover. Patent Document 3 discloses a ballpoint pen that uses a resin ink guide core in the ball seat. Patent Document 4 discloses a ballpoint pen in which a support member with a resilient action is attached to the rear end of a cylindrical seat member that is inserted into a cylinder that holds the ball. Patent Document 5 discloses a ballpoint pen that uses a spring to press the ball toward the tip. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-252655 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-148423 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-113874 [Patent Document 4] Japanese Patent Publication No. 2019-10843 [Patent Document 5] Japanese Patent Application Publication No. 2019-10844 Summary of the Invention [Problem to be solved by the invention]

[0004] An embodiment of the present disclosure aims to provide a ballpoint pen refill and a ballpoint pen that ensure sufficient ball holding force and are capable of drawing lines like those drawn with a calligraphy brush, while forming the ball receiving seat and the member that presses the ball toward the tip as a single member. [Means for solving the problem]

[0005] A first aspect of the present application is a ballpoint pen refill comprising an ink reservoir tube made of synthetic resin that contains ink therein, a ball holder made of synthetic resin that is attached to the tip of the ink reservoir tube, a ball pressing rod that is attached inside the ball holder, and a writing ball that is housed in the tip of the ball holder and whose rear end is held by the ball pressing rod, wherein the ball pressing rod comprises a fixed part that is fixed to the ball holder, a movable part that is slidable in the front-to-rear direction relative to the ball holder, a compression part that connects the fixed part and the movable part, and a retraction regulating part that protrudes from the tip of the fixed part and has a gap between it and the rear end of the compression part.

[0006] According to the configuration of the first aspect of the present application, the ball pressing rod can serve both as a receiving seat for the ball and as a spring that allows the writing ball to slide back and forth.

[0007] A second aspect of the present invention is characterized in that, in addition to the configuration of the first aspect, the compression portion has a bellows shape. This configuration makes it easy to form the ball pressing rod by injection molding of synthetic resin, and the bellows shape makes it possible to ensure elastic force.

[0008] A third aspect of the present application is characterized in that, in addition to the configuration of the first or second aspect, a slit is formed from the tip of the ball holder toward the rear.

[0009] A fourth aspect of the present application is a configuration according to any one of the first to third aspects, further comprising: All components except the ink are made of synthetic resin. To Since no metal materials are used, there is no need to separate the materials from metals for disposal, and the components can be easily recycled.

[0010] A ballpoint pen according to a fifth aspect of the present application is characterized in that the ballpoint pen refill according to any one of the first to fourth aspects is housed in a barrel. [Effects of the Invention]

[0011] Since the embodiments of the present disclosure are configured as described above, it is possible to provide a ballpoint pen refill and a ballpoint pen that can form the ball receiving seat and the member that presses toward the tip as a single component, while ensuring sufficient ball holding force and also enabling the creation of lines like those drawn with a calligraphy brush. [Brief explanation of the drawings]

[0012] [Figure 1] The ballpoint pen of the embodiment is shown in a front view (A), a side view (B), and a cross-sectional view taken along line II of (A) (C). [Figure 2] The ballpoint pen refill used in the ballpoint pen of the first embodiment in FIG. 1 is shown in a front view (A), a side view (B), and a cross-sectional view (C) taken along line II-II of (B). [Figure 3] FIG. 2(B) is an enlarged view of the tip portion of FIG. 2(C). [Figure 4] The ball holder used in the ballpoint pen refill of Figure 2 is shown in a front view (A), a side view (B), a bottom view (C), a plan view (D), a front end oblique view (E), a rear end oblique view (F), and a cross-sectional view (G) taken along line IV-IV of (B). [Figure 5] The ball pressure rod used in the ballpoint pen refill in Figure 2 is shown in a front view (A), left side view (B), right side view (C), bottom view (D), plan view (E), front end oblique view (F), and rear end oblique view (G). [Figure 6] The pressed state of the writing ball in the ballpoint pen refill of FIG. 2 is shown in a front view (A), a side view (B), and a cross-sectional view (C) taken along line VI-VI of (B). [Figure 7] FIG. 6(B) is an enlarged view of the tip portion of FIG. 6(C). [Figure 8] The compressed state of the ball pressing rod in Figure 5 is shown in front view (A), left side view (B), right side view (C), bottom view (D), plan view (E), front end perspective view (F) and rear end perspective view (G). [Figure 9] A ballpoint pen refill used in a ballpoint pen of a second embodiment is shown in a front view (A), a side view (B), and a cross-sectional view (C) taken along line IX-IX of (B). [Figure 10] FIG. 9(B) is an enlarged view of the tip portion of FIG. 9(C). [Figure 11] The ball holder used in the ballpoint pen refill of Figure 9 is shown in a front view (A), a side view (B), a bottom view (C), a plan view (D), a front end oblique view (E), a rear end oblique view (F), a cross-sectional view (G) taken along line XI-XI of (B), an enlarged view (H) of the front end portion of (E), and an enlarged view (I) of the front end portion of (G). [Figure 12] FIG. 10 is an enlarged perspective view of the tip portion of the ballpoint pen refill of FIG. 9. [Figure 13] The pressed state of the writing ball in the ballpoint pen refill of FIG. 9 is shown in a front view (A), a side view (B), and a cross-sectional view (C) taken along line XIII-XIII of (B). [Figure 14] FIG. 13(B) is an enlarged view of the tip portion of FIG. 13(C). DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, the "front end" refers to the side of the ballpoint pen where the writing ball is provided, and the "rear end" refers to the opposite side. Furthermore, common reference numerals in each drawing indicate the same components or parts even if not specifically mentioned in the description of the following drawings. Furthermore, in each drawing, left The side is the tip side and the bottom side, right The side is the rear end side and the flat side.

[0014] (1) First embodiment <Appearance> 1A shows a ballpoint pen 10 of the first embodiment in a front view, a side view, and a cross-sectional view along line II in FIG. 1A. As shown in these figures, the ballpoint pen 10 of this embodiment has a barrel 30 with a tail plug 40 attached to the rear end, and a cap 36 with a clip 37 attached to the tip of the barrel 30. The barrel 30, tail plug 40, and cap 36 are all made of a synthetic resin such as polycarbonate.

[0015] As shown in the cross-sectional view of FIG. 1(C), in the ballpoint pen 10 of this embodiment, a ballpoint pen refill 20 containing ink 24 is built into a barrel 30, and the rear end of the ballpoint pen refill 20 is supported by abutting against a tail plug 40. In this ballpoint pen refill 20, a ball holder 60 is attached to the tip of the ink reservoir 23 containing the ink 24. The tip of the ball holder 60 holds a writing ball 26. A ball pushing rod 50 that urges the writing ball 26 toward the tip is attached inside the ball holder 60, the structure of which will be described later. Furthermore, a grease-like follower 25 is injected into the rear end of the ink 24 contained in the ballpoint pen refill 20. The ink 24 and follower 25 will be described in detail later. The barrel 30 has a cylindrical shape with a tapered tip, and the tip of the ball holder 60 protrudes from an opening provided at the tip.

[0016] <20 ballpoint pen refills> 2 shows a ballpoint pen refill 20 used in the ballpoint pen 10 of FIG. 1 in a front view (A), a side view (B), and a cross-sectional view (C) taken along line II-II in FIG. 2(B). As described above, the ballpoint pen refill 20 has an external appearance in which a ball holder 60 is attached to the tip of a cylindrical ink reservoir tube 23 made of synthetic resin, the ball holder 60 holding a writing ball 26 made of synthetic resin such as polyacetal or polyether ether ketone. The ballpoint pen refill 20 in FIG. 2 shows a state in which no writing pressure is applied to the writing ball 26.

[0017] As shown in the cross-sectional view of Figure 2(C), the writing ball 26 is held at the tip of the ball holder 60. A ball pushing rod 50 that urges the writing ball 26 toward the tip is attached inside the ball holder 60. Furthermore, the ink 24 is contained in the ink containing tube 23, as described above.

[0018] <Ink 24> The ink 24 of this embodiment is an aqueous gel ink. This ink 24 preferably contains a color pigment, a polyvinyl alcohol-based resin as a dispersing resin, and an alkali-swelling associative thickener. Each component will be described below.

[0019] The color pigment may be either inorganic or organic, including black pigments such as carbon black, red pigments such as permanent carmine FB, lake red C, permanent red FGR, and fast red, and blue pigments such as phthalocyanine blue, fast sky blue, and ultramarine blue, as well as mixtures thereof.

[0020] Carbon black typically used as a color pigment for inks may be commercially available carbon black or rubber carbon black, but is preferably commercially available carbon black for use as a black colorant for inks, paints, etc. Any type of carbon black, such as channel black, furnace black, acetylene black, or thermal black, may be used. The particle size of the carbon black is preferably 10 to 80 nm. The surface condition of the carbon black may be acidic, neutral, or alkaline, but carbon black with a pH of 7.5 to 8.5 is preferably used.

[0021] The content of the color pigment varies depending on the type of color pigment, but is preferably 8 to 25% by weight of the total amount of ink. If it is less than 8% by weight, the amount of dispersing resin will result in insufficient coloring, and the color quality of the drawn lines will be unsatisfactory. On the other hand, if it exceeds 25% by weight, the amount of polyvinyl alcohol-based resin required to stably disperse the color pigment will also need to be increased, resulting in high viscosity and a heavy writing feel.

[0022] The polyvinyl alcohol resin as a dispersing resin is contained as a water-soluble resin for uniformly dispersing color pigments such as carbon black in water and as a fixing agent for paper.

[0023] The polyvinyl alcohol resin may be any resin obtained by saponifying polyvinyl acetate, preferably polyvinyl alcohol with a degree of polymerization of 300 to 2000 and a degree of saponification of 80 to 95 mol %. If the degree of polymerization is too low, the viscosity of the ink may be too low, and even when used in combination with an alkali-swelling associative thickener, ink blobbing may not be sufficiently suppressed. Furthermore, if the degree of saponification is too low, the water resistance of the drawn lines may be reduced.

[0024] Furthermore, the polyvinyl alcohol resin used in this embodiment is not limited to saponified polyvinyl acetate containing 100% vinyl acetate. A polyvinyl alcohol copolymer obtained by copolymerizing other vinyl monomers or a polyvinyl alcohol resin modified by acetylation or the like may be used as long as the content is approximately 10 mol % or less. However, a saponified polyvinyl acetate containing 100% vinyl acetate is preferred. The content of the polyvinyl alcohol resin is preferably 2 to 10 wt % of the total ink weight. If the content is less than 2 wt %, the dispersion of the color pigment is not sufficiently stabilized, resulting in reduced storage stability, such as the color pigment settling over time. If the content exceeds 10 wt %, the viscosity increases too much, resulting in a heavy writing feel.

[0025] The alkali-swelling associative thickener can impart thixotropic behavior to the ink. That is, even if the ink has a high viscosity when left standing, the viscosity decreases when a high shear force is applied during writing, making it possible to write.

[0026] Alkali-swelling associative thickeners are unneutralized acrylic polymers that are water-soluble or water-swellable polymers modified with hydrophobic groups, as well as their aqueous solutions and emulsions. Examples include hydrophobically modified alkali-soluble emulsions, hydrophobically modified poly(meth)acrylic acid, (meth)acrylic acid copolymers, mixtures thereof, and their aqueous solutions and emulsions. Examples of hydrophobic groups include linear and cyclic hydrocarbon groups, aromatic hydrocarbon groups, halogenated alkyl groups, organosilicon groups, and fluorocarbon groups. The hydrophobic group modification can be achieved by esterification with a hydrophobic chain transfer agent (e.g., dodecyl mercaptan), a hydrophobic monomer (e.g., decyl methacrylate, nonionic vinyl monomer), a hydrophobic group-containing alcohol (e.g., dodecanol), or a nonionic surfactant. Alkali-swelling associative thickeners with the above-described structure are neutralized with alkali to form a network structure, which swells and spreads throughout the dispersion medium, thereby thickening the ink. Furthermore, the hydrophilic or hydrophobic groups in the molecule can associate with each other, or with the dispersing resin, by forming hydrogen bonds, etc. Although the association increases the viscosity, high shear force can destroy the association state, reducing the viscosity and allowing the polymer to exhibit good fluidity.

[0027] In this way, the addition of an alkali-swelling associative thickener can impart thixotropy to the ink. Specifically, the addition of an alkali-swelling associative thickener can increase the thixotropy index (TI value), expressed as the ratio (η0.6 / η6) of the viscosity at 0.6 rpm (η0.6) to the viscosity at 6 rpm (η6) measured using a rotational viscometer, to 3.0 or higher. The TI value is preferably approximately 3.0 to 10. It is preferable that the thixotropy index is within the above range and that the viscosity at 6 rpm is 0.3 Pa·s or higher. While it is possible to achieve the thixotropy index within the above range by adjusting the content of the color pigment and polyvinyl alcohol-based resin, if the thickening effect is insufficient and the viscosity at 6 rpm is too low, the viscosity at rest will be low, and ink blobbing will not be sufficiently prevented. In this regard, the addition of an alkali swelling associative thickener makes it possible to increase the viscosity and impart thixotropy to the ink so that it can prevent blobbing and satisfy both the writability and the ink bloating. On the other hand, by adjusting the amount of alkali swelling associative thickener added, it is possible to keep the viscosity of the ink at a rotation speed of 6 rpm, as measured with an EM-type rotational viscometer, to less than 25 Pa·s, even if the ink is thickened. By increasing the viscosity to a range where the viscosity is less than 25 Pa·s under shear stress, the ink blobbing caused by the viscosity increase can be prevented without impairing the writability. Te's Prevention can be made possible.

[0028] Associative thickeners include aqueous solutions of urethane block copolymers modified with urethane monomers, etc. Urethane associative thickeners can also impart thixotropy, in which molecules repeatedly associate and separate depending on the magnitude of shear force, but the level of thickening is insufficient, or the viscosity reduction under high shear force is insufficient.

[0029] The alkali-swelling associative thickener is preferably present in an amount of 0.1 to 5.0% by weight relative to the total amount of ink. If it is less than 0.1% by weight, the ink will not be sufficiently thixotropic. If it exceeds 5.0% by weight, the viscosity will increase too much, resulting in poor writing performance.

[0030] In the ink of this embodiment, in order for the alkali swelling associative thickener to effectively impart thixotropy, the ink is preferably neutral to alkaline, specifically, pH 7.0 to 9.5.

[0031] Therefore, an alkaline compound may be added to the ink to adjust the pH to within the above range. Examples of the alkaline compound that can be used include triethanolamine, monoethanolamine, diethanolamine, and ammonia.

[0032] The ink of this embodiment may further contain additives such as a dispersion stabilizing aid, a surfactant, a preservative, an antifoaming agent, etc. Preferred dispersion stabilizing aids include ethylene glycol, diethylene glycol, triethylene glycol, and glycerin.

[0033] Inks containing the above-mentioned components have thixotropy. Specifically, the thixotropy index (TI value), expressed as the ratio (η0.6 / η6) of the viscosity at 0.6 rpm (η0.6) to the viscosity at 6 rpm (η6) measured with an EM-type rotational viscometer, is preferably 3.0 or greater, and the viscosity at 6 rpm is preferably 0.3 Pa·s or greater. The thixotropy index is more preferably 3.5 or greater. Furthermore, the viscosity at 6 rpm is more preferably 0.5 Pa·s or greater.

[0034] The viscosity measured with a rotational viscometer at a rotation speed of 6 rpm is preferably 25 Pa·s or less, where the viscosity is measured at a rotation speed of 100 rpm and 25°C using an EM type rotational viscometer.

[0035] 2(C), a grease-like follower 25 is injected into the rear end of the ink 24 to prevent the ink 24 from leaking out from the rear end of the ink containing tube 23. This follower 25 moves toward the tip as the ink 24 is consumed through writing. Note that a cylindrical float made of synthetic resin, adjusted to have the same specific gravity as the follower 25, may be suspended within this follower 25.

[0036] <Ball holder 60> Figure 3 is an enlarged view of the tip portion of Figure 2(C). Ball holder 60 is attached to the tip of ink reservoir 23 and holds writing ball 26 at its tip. Inside ball holder 60 is also attached ball pressing rod 50 that urges writing ball 26 toward the tip.

[0037] Figure 4 shows a ball holder 60 used in the ballpoint pen refill 20 of Figures 2 and 3 in a front view (A), a side view (B), a bottom view (C), a plan view (D), a front end perspective view (E), a rear end perspective view (F), and a cross-sectional view (G) taken along line IV-IV of Figure 4(B). The ball holder 60 is made of a synthetic resin such as polyacetal or polyether ether ketone, and as shown in Figure 3, from the rear end side, is composed of an attachment portion 61, a flange portion 62, an intermediate portion 63, and a front end portion 64.

[0038] The mounting portion 61 has a substantially cylindrical shape and is the portion that is press-fitted onto the tip of the ink containing tube 23, as shown in FIG. 3. A rear end opening 65 that is an opening that leads to the interior is formed at the rear end of the mounting portion 61. The flange portion 62 is a disk-shaped portion that expands in diameter toward the tip of the mounting portion 61, and when the mounting portion 61 is press-fitted onto the tip of the ink containing tube 23, it abuts against the tip of the ink containing tube 23 to prevent further press-fitting. On both the left and right sides of the flange portion 62, there are formed chamfered portions 62A that are chamfered into a flat shape. These chamfered portions 62A are the portions that are gripped with a tool when the ball holder 60 is inserted into the ink containing tube 23.

[0039] The intermediate portion 63 has a slightly tapered cylindrical shape, and its outer diameter is smaller than that of the attachment portion 61. A tip portion 64 having a generally cylindrical shape and an even smaller outer diameter is formed on the tip side of the intermediate portion 63. An abutment portion 63A, which is a step between the intermediate portion 63 and the tip portion 64, is a portion that abuts against the inside of the tip opening of the barrel 30 when the ballpoint pen refill 20 is attached to the barrel 30 (see FIG. 1(C)). In addition, the tip side portion of the tip portion 64 is a tapered portion 64A that is tapered, and the periphery of a tip opening 68, which is an opening provided at the tip, is a crimped portion 64B that is narrowed inward.

[0040] The inside of the ball holder 60 has a hollow structure as shown in Figure 4(G). This hollow structure is composed of a back hole 66 whose inner diameter gradually decreases from the rear end opening 65 toward the tip end, and an ink hole 67 that connects the back hole 66 to the tip end opening 68. The back hole 66 has a rear reduced diameter portion 66A, which is a step near the middle of the intermediate portion 63, and an ink hole 67 that connects the back hole 66 to the tip end opening 68. 63 The diameter of the ball holder 60 is gradually reduced from the rear end opening 65 through the back hole 66 and the ink hole 67 to the tip opening 68 via the intermediate reduced diameter section 66B, which is a step near the tip of the ball holder 60. The diameter of the ball holder 60 is also gradually reduced from the back hole 66 to the ink hole 67 at the tip reduced diameter section 66C, which is a step between the two. In other words, the ball holder 60 extends from the rear end opening 65 through the back hole 66 and the ink hole 67 to the tip opening 68.

[0041] 5 shows ball pressing rod 50, which is mounted inside ball holder 60, in a front view (A), left side view (B), right side view (C), bottom view (D), plan view (E), front end perspective view (F), and rear end perspective view (G). Ball pressing rod 50 is composed of fixed part 51, movable part 52 equipped with pressing part 53, compression part 54 interposed between fixed part 51 and movable part 52, and retraction restriction part 55 protruding from fixed part 51 toward the front end.

[0042] Although the fixed portion 51, the compressed portion 54, and the movable portion 52 are all generally cylindrical, two opposing surfaces are formed as a large flat portion 50A and a small flat portion 50B, which are cut into flat surfaces, and groove-shaped ink grooves 57 are formed on the other two opposing surfaces, resulting in the planar shape shown in Fig. 5(E). The area of ​​the large flat portion 50A is larger than the area of ​​the small flat portion 50B.

[0043] The fixed portion 51 is fixed to the ball holder 60 when the ball pushing rod 50 is attached to the ball holder 60 by press-fitting the larger-diameter press-fit portion 51A into the front part of the rear reduced diameter portion 66A (see FIG. 4(G)) of the back hole 66 (see FIG. 3). The movable portion 52 is a portion that is slidable in the front-to-rear direction relative to the ball holder 60. The rear abutment portion 52A, which is the front end edge of the movable portion 52, is a portion that abuts against the intermediate reduced diameter portion 66B (see FIG. 4(G)) of the back hole 66 when the ball pushing rod 50 is attached to the ball holder 60 (see FIG. 3).

[0044] The pressing portion 53, which projects from the movable portion 52 toward the tip, is the portion that abuts against the rear end of the writing ball 26 when the ball pressing rod 50 is attached to the ball holder 60 (see FIG. 3), and is composed of a wider wide portion 53A located on the rear side and a narrower narrow portion 53C located on the front side. The step between the wide portion 53A and the narrow portion 53C forms the front abutment portion 53B. The front abutment portion 53B is the portion that abuts against the tip reduced diameter portion 66C of the back hole 66 (see FIG. 4(G)) when the ball pressing rod 50 is attached to the ball holder 60. Furthermore, when the front abutment portion 53B abuts against the tip reduced diameter portion 66C, the narrow portion 53C is located inside the ink hole 67, and a ball pressing surface 53D provided at the tip of the narrow portion 53C abuts against the rear end of the writing ball 26. In other words, the rear end side of the writing ball 26 is held by the pressing portion 53 of the ball pressing rod 50 (see FIG. 3).

[0045] The compression portion 54 connects the fixed portion 51 and the movable portion 52 by bending twice in an accordion-like shape. The rearward bent portion is the rearward bent portion 54A, and the forward bent portion is the forward bent portion 54B. The retraction restriction portion 55 has a plate-like shape extending from the fixed portion 51 toward the movable portion 52, and when the ball pushing rod 50 is attached to the ball holder 60 and no writing pressure is applied to the writing ball 26, a gap is generated between the fixed portion 51 and the movable portion 52 (see FIG. 3). This gap is the retraction gap 56, which is the range within which the movable portion 52 can retract.

[0046] 2(C) and 3, the ink 24 contained in the ink reservoir 23 flows from the back hole 66 of the ball holder 60 through the ink hole 67 to the writing ball 26, where it is transferred to the writing surface to form a drawn line. At this time, the ball pushing rod 50 attached to the inside of the ball holder 60 is formed with an ink groove 57, a large flat surface 50A, and a small flat surface 50B, and further the pushing portion 53 is also flat, so that the ball pushing rod 50 does not block the flow of the ink 24 toward the tip.

[0047] <Operation> 6 shows the state in which the writing ball 26 at the tip of the ballpoint pen refill 20 shown in FIG. 2 is pressed by writing pressure, using a front view (A), a side view (B), and a cross-sectional view (C) taken along the line VI-VI in FIG. 6(B). In this state, the writing ball 26 is retracted into the ball holder 60. As shown in FIG. 7, which is an enlarged view of the tip portion of FIG. 6(C), the movable part 52 is retracted by the pressure exerted by writing pressure on the writing ball 26, and the rear contact part 52A of the movable part 52 and the intermediate reduced diameter part 66B of the back hole 66 are separated. Meanwhile, the movable part 52 abuts against the retraction restriction part 55, and the retraction gap 56 that was present in the state shown in FIG. 3 is eliminated.

[0048] 8 shows the ball pressing rod 50 in the state shown in FIG. 7 in a front view (A), a left side view (B), a right side view (C), a bottom view (D), a plan view (E), a front end perspective view (F), and a rear end perspective view (G). As shown in these figures, the retraction of the movable part 52 causes the compression part 54 to bend and compress, which causes the rear end edge of the movable part 52 and the retraction restriction part 55 to come into contact with each other. destination The edges come into contact and the setback gap 56 as shown in FIG. 5 disappears.

[0049] As a result, the tip edge of the retraction restriction portion 55 defines the limit of retraction of the writing ball 26 due to pressure. The intermediate reduced-diameter portion 66B of the back hole 66 defines the limit of forward movement of the ball pressure rod 50. The spring effect of the compression portion 54 ensures that the writing ball 26 is always biased forward. Furthermore, when writing pressure is applied to the writing ball 26, the compression portion 54 compresses and bends through the movable portion 52, giving the user the feeling of bending the pen tip. This allows for the creation of lines with strokes, flickers, and strokes reminiscent of those drawn with a brush.

[0050] Furthermore, the ball holder 60 and ball pushing rod 50 are shaped to be injection moldable from synthetic resin, and the ink groove 57, large flat portion 50A, and small flat portion 50B provided in the ball pushing rod 50 ensure an ink flow path inside the ball holder 60. Furthermore, all of the components constituting the ballpoint pen 10, except for the ink, are made of synthetic resin and do not use metal parts, so there is no need to sort them when disposing of them, and the synthetic resin material is easily recycled.

[0051] (2) Second embodiment <Appearance> The appearance of the ballpoint pen 10 of the second embodiment is the same as that of the first embodiment, as shown in the front view of FIG. 1(A), the side view of FIG. 1(B), and the cross-sectional view of FIG. 1(C).

[0052] <20 ballpoint pen refills> 9A, 9B, and 9C show a ballpoint pen refill 20 used in a ballpoint pen 10 according to a second embodiment, in a front view (A), a side view (B), and a cross-sectional view (C) taken along line IX-IX in FIG. 9B. The structure of the ballpoint pen refill 20 according to the second embodiment is the same as that of the first embodiment, except that it is provided with an extension 64D (see FIG. 10), which will be described later. The ink 24 is also the same as that of the first embodiment.

[0053] <Ball holder 60> Figure 10 is an enlarged view of the tip portion of Figure 9(C). Ball holder 60 is attached to the tip of ink reservoir 23 and holds writing ball 26 at its tip. An extension 64D that extends toward the tip is formed at the tip of ball holder 60. A ball pressing rod 50 that urges writing ball 26 toward the tip is also attached inside ball holder 60.

[0054] FIG. 11 shows a ball holder 60 used in the ballpoint pen refill 20 of FIGS. 9 and 10, including a front view (A), a side view (B), a bottom view (C), a plan view (D), a front end perspective view (E), a rear end perspective view (F), a cross-sectional view (G) taken along line XI-XI of FIG. 11B, an enlarged view (H) of the front end portion of FIG. 11E, and an enlarged view (I) of the front end portion of FIG. 11G. The ball holder 60 is made of a synthetic resin such as polyacetal or polyether ether ketone, and as shown in FIG. 10, from the rear end side, comprises an attachment portion 61, a flange portion 62, an intermediate portion 63, and a front end portion 64. The structure of the attachment portion 61 is the same as that of the first embodiment.

[0055] The structure of the intermediate portion 63 is the same as that of the first embodiment. The structure of the tip portion 64 is also the same as that of the first embodiment, except that an extension portion 64D is formed that extends from the tip edge of the crimped portion 64B toward the tip.

[0056] The inside of the ball holder 60 has a hollow structure as shown in Figure 11(G) This hollow structure is also the same as that of the first embodiment.

[0057] The inner peripheral surface of the crimped portion 64B is formed with a sealing surface 64C that abuts against the outer peripheral surface of the writing ball 26 (see Figures 11(G) and (I)). This sealing surface 64C prevents ink from leaking from the tip when not writing. Furthermore, the edge of the tip of the crimped portion 64B extends toward the tip, forming an extension 64D. A plurality of slits 64E are formed from the tip edge of this extension 64D to near the tip edge of the rear crimped portion 64B.

[0058] In the ballpoint pen refill 20 of this embodiment, as shown in the enlarged perspective view of the tip portion in Fig. 12, the writing ball 26 exposed from the tip is held by an extension 64D that extends further from the crimped portion 64B. Here, in the ballpoint pen refill 20 of the first embodiment, which does not have the extension 64D, the projection dimension of the writing ball 26 from the tip edge of the crimped portion 64B is approximately 30% of the diameter of the writing ball 26. On the other hand, in the ballpoint pen refill 20 of this embodiment, the extension 64D is provided, so that the projection dimension of the writing ball 26 from the tip edge of the extension 64D is approximately 20% of the diameter of the writing ball 26, further expanding the area that is held. Furthermore, the multiple slits 64E provided in the extension 64D ensure that the outflow of the ink 24 is not hindered even when the extension 64D is present.

[0059] The ball pressing rod 50 (see FIG. 10) attached inside the ball holder 60 is the same as in the first embodiment.

[0060] FIG. 13 shows the state in which the writing ball 26 at the tip of the ballpoint pen refill 20 shown in FIG. 9 is pressed by writing pressure, using a front view (A), a side view (B), and a cross-sectional view (C) along XIII-XIII in FIG. 13(B). In this state, the writing ball 26 retracts into the ball holder 60. As shown in FIG. 14, which is an enlarged view of the tip of FIG. 13(C), the movable part 52 retracts due to the pressure applied by writing pressure to the writing ball 26, and the rear contact part 52A of the movable part 52 and the intermediate reduced diameter part 66B of the back hole 66 are separated. Meanwhile, the movable part 52 abuts against the retraction restriction part 55, eliminating the retraction gap 56 that was present in the state shown in FIG. 10. The shape of the ball pressing rod 50 shown in FIG. 14 is the same as that shown in FIG. 8 in the first embodiment.

[0061] As described above, in this embodiment, as in the first embodiment, the tip edge of the retraction restriction portion 55 defines the limit of retraction caused by pressure from the writing ball 26. The intermediate reduced-diameter portion 66B of the back hole 66 defines the limit of advancement of the ball pushing rod 50. The spring effect of the compression portion 54 ensures that the writing ball 26 is always biased forward. Furthermore, when writing pressure is applied to the writing ball 26, the compression portion 54 compresses and bends through the movable portion 52, giving the user the feeling of bending the pen tip. This allows for the creation of lines with strokes, flickers, and strokes reminiscent of those drawn with a calligraphy brush.

[0062] Furthermore, the ball holder 60 and ball pushing rod 50 are shaped to be injection moldable from synthetic resin, and the ink groove 57, large flat portion 50A, and small flat portion 50B provided in the ball pushing rod 50 ensure an ink flow path inside the ball holder 60. Furthermore, all of the components constituting the ballpoint pen 10, except for the ink, are made of synthetic resin and do not use metal parts, so there is no need to sort them when disposing of them, and the synthetic resin material is easily recycled. [Industrial Applicability]

[0063] The present invention is applicable to ballpoint pen refills and ballpoint pens using the same. [Explanation of symbols]

[0064] 10 ballpoint pens 20 ballpoint pen refill 23 ink reservoir tube 24 ink 25 Followers 26 Writing Balls 30. Shaft tube 36. Cap 37. Clip 40 tail plug 50 Ball pressing rod 50A Large flat portion 50B Small flat portion 51 Fixed part 51A Press-fit part 52 Movable part 52A Rear contact part 53 Pressing portion 53A Wide portion 53B Front contact portion 53C Narrow section 53D Ball pressing surface 54 Compression section 54A Backward bending section 54B Forward bending section 55 Retraction restriction portion 56 Retraction gap 57 Ink groove 60 Ball holder 61 Mounting part 62 Flange part 62A Face milled part 63 Intermediate section 63A Abutment section 64 Tip 64A Tapered section 64B Crimped section 64C Sealing surface 64D Extension 64E Slit 65 Rear end opening 66 Back hole 66A Rear reduced diameter portion 66B Intermediate reduced diameter portion 66C Tip reduced diameter 67 Ink hole 68 Tip opening

Claims

1. an ink reservoir tube made of synthetic resin that contains ink therein; a synthetic resin ball holder attached to the tip of the ink reservoir; a ball pressing rod attached inside the ball holder; a writing ball that is accommodated in the tip of the ball holder and whose rear end side is held by the ball pressing rod; A ballpoint pen refill comprising: The ball pressing rod is a fixing portion fixed to the ball holder; a movable part that is slidable in the front-rear direction relative to the ball holder; a compression part connecting the fixed part and the movable part; a retraction restricting portion that protrudes from a tip end of the fixing portion and has a gap between it and a rear end of the compressing portion; A ballpoint pen refill comprising:

2. 2. The ballpoint pen refill according to claim 1, wherein the compressed portion is bellows-shaped.

3. 2. The ballpoint pen refill according to claim 1, wherein a slit is formed from the tip of the ball holder toward the rear.

4. 3. The ballpoint pen refill according to claim 2, wherein a slit is formed from the tip of the ball holder toward the rear.

5. 5. The ballpoint pen refill according to claim 1, wherein all components except for the ink are made of synthetic resin.

6. A ballpoint pen, comprising a ballpoint pen refill according to any one of claims 1 to 4 housed in a barrel.

7. A ballpoint pen, comprising the ballpoint pen refill according to claim 5 housed in a barrel.

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