Writing refills

Abstract

To provide a writing refill group with which differences in ink consumption per unit writing distance can be easily recognized among multiple writing refills containing ink of the same color tone, and a writing instrument group which contains the writing refill group in barrels.SOLUTION: There is provided a writing refill 1 in which a writing part 3 is attached to one end of a transparent or translucent ink containing tube 2, and ink 6 is contained in the tube of the ink containing tube 2. In a writing refill group in which the constituent parts of the writing refill 1 are the same, and the outer diameter of the ink containing tube 2 of the writing refill 1 and the overall length of the writing refill 1 are the same, ink of the same color tone is contained in the ink containing tube 2, and the color difference (brightness) of the ink containing tube 2 varies depending on the amount of ink consumed per unit writing distance of the writing refill 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a group of writing refills and a group of writing implements in which differences in ink consumption among a plurality of writing refills containing ink of the same hue can be easily distinguished. [Background technology]

[0002] For example, a writing refill (ballpoint pen refill) used in a ballpoint pen writing instrument is generally attached by press-fitting a ballpoint pen tip or a coupling member that supports the ballpoint pen tip as a writing part into one end (front end) of an ink reservoir tube. The ink reservoir tube is made of a transparent or semi-transparent resin material, such as polypropylene, to ensure ease of molding and visibility of the ink amount.

[0003] A typical ink reservoir tube molded from a resin material such as polypropylene often has an outer diameter of about 3 mm and an inner diameter of about 1.8 mm, as described in paragraph

[0021] of Patent Document 1, for example. The ink reservoir tube shown in this example is relatively thick, so there is a limit to the amount of ink that can be stored in the ink reservoir tube, which results in a practical problem in that it is not possible to obtain a sufficient writing distance.

[0004] Therefore, the present applicant has proposed a thin-walled writing refill in which the outer diameter of the ink reservoir tube is approximately the same as that of the conventional refill described above, and the inner diameter of the ink reservoir is enlarged, and this is disclosed in Patent Documents 2 and 3. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-198291 [Patent Document 2] International Publication No. WO2017 / 061570 [Patent Document 3] International Publication No. WO2018 / 180679 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in this type of writing refill that uses the ink reservoir tube described above, different ball diameters are available for the writing portion, and due to the difference in ball diameter, each writing refill consumes different amounts of ink for a given writing distance. However, these writing refills are generally formed to have substantially the same external size, except for the tip of the writing part.

[0007] Therefore, in order to select the desired writing refill from a group of writing refills that have multiple writing refills with different ink consumption amounts per unit writing distance, one must choose a method such as visually identifying the fine writing tip or identifying it by reading small text information written on the surface of the ink reservoir tube, etc. However, it is virtually impossible for an average user to visually check the minute writing tip (for example, ball diameter) to determine whether or not the writing refill is the one they want. Furthermore, even if they try to read the text information written on the ink reservoir, it is easy to misread it because the text information is so small, making it practically impossible to accurately select the writing refill they want.

[0008] Therefore, the object of this invention is to provide a group of writing refills and a group of writing instruments that house these refills in a barrel, in which the difference in ink consumption per unit writing distance between multiple writing refills containing ink of the same hue can be easily identified. [Means for solving the problem]

[0009] The writing refill group according to the present invention, which has been made to solve the above-mentioned problems, comprises a transparent or semi-transparent ink reservoir tube attached to one end thereof. , brush A writing refill is attached to a joint member that supports a writing portion, and ink is contained in the ink containing tube. t and components of said writing refill. The coupling member and the tail plug attached to the other end of the ink reservoir tube In a group of writing refills in which the outer diameter of the ink reservoir tube of each writing refill and the overall length of each writing refill are the same, the ink reservoir tubes contain ink of the same hue, and the ink consumption per unit writing distance of each writing refill is determined as follows: By varying the inner diameter of the ink containing tube, Color difference of each ink reservoir of Different made It is characterized by:

[0010] In this case, in one preferred embodiment, the ink reservoir tubes contain the same type of black ink, such as oil-based or water-based ink, and are set so that the difference in lightness (L*) from the outer surface of each ink reservoir tube is equal to or greater than [difference in wall thickness of ink reservoir tube (mm) × 10], depending on the amount of ink consumed per unit writing distance of the writing refill.

[0011] In a more preferred embodiment, a backflow preventer is accommodated at the rear end of the ink at the other end side of the ink containing tube, and the viscosity of the backflow preventer is selected to differ depending on the inner diameter of the ink containing tube.

[0012] The group of writing instruments according to the present invention consists of a plurality of writing instruments each having the above-mentioned writing refill housed in a barrel, and the barrels are combined so that the thickness of the barrel varies depending on the amount of ink consumed per unit writing distance of the writing refill housed in the barrel. [Effects of the Invention]

[0013] According to the group of writing refills of the present invention described above, the ink reservoir tubes contain ink of the same type and hue, and the color difference of each ink reservoir tube varies depending on the amount of ink consumed per unit writing distance of the writing refill, so that the desired writing refill can be easily selected.

[0014] In addition, the writing instrument group of this invention consists of a plurality of writing instruments, each of which contains a writing refill that constitutes the writing refill group described above, housed in a barrel, and the barrels are combined so that the thicknesses of the barrels differ depending on the amount of ink consumed per unit writing distance of the writing refill. Therefore, the transmittance of the barrel changes, and the color difference (brightness) of each ink reservoir tube accommodated in the barrel also differs, so that the desired writing implement can be easily selected. Furthermore, by molding the ink reservoir tube to be thin, the amount of resin used can be reduced, which contributes to reducing the environmental impact. [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows the external configuration of a group of writing refills according to the present invention, where (A) to (C) show ballpoint pen refills with different ink consumption amounts per unit writing distance. [Figure 2] 2(A) to 2(C) are cross-sectional views taken along the axial direction of each of the ballpoint pen refills shown in FIG. 1(A) to 2(C). [Figure 3] 2 shows the individual components of the tail plug to be attached to the ink reservoir tube of the ballpoint pen refill shown in FIG. 1, where (A) is a perspective view from the front end, (B) is a perspective view from the rear end, (C) is a front view, and (D) is a plan view. [Figure 4] 2 is a perspective view showing the writing instrument in a state in which one of the ballpoint pen refills shown in FIG. 1 is housed in a barrel. [Figure 5] In the writing implement shown in FIG. 4, (A) is a plan view, (B) is a front view, and (C) is a cross-sectional view along the axial direction. DETAILED DESCRIPTION OF THE INVENTION

[0016] A group of writing refills and a group of writing implements according to the present invention will be described based on the embodiments shown in the drawings.

[0017] <Ballpoint pen refills (writing refills)> First, Figures 1(A) to 1(C) and Figures 2(A) to 2(C) show examples of ballpoint pen refills that make up a group of writing refills, and the same alphabetical symbols in Figures 1 and 2 indicate the same ballpoint pen refill in external view and cross-sectional view. This ballpoint pen refill 1 is attached by press-fitting an ink reservoir 2 to one end (front end) of the ink reservoir 2 and a coupling member 4 supporting a ballpoint pen tip 3 as a writing part. A tail plug 5 is fitted into the other end (rear end) of the ink reservoir 2.

[0018] In addition, ink 6 is contained in the ink containing tube 2 from immediately after the coupling member 4 toward the rear end side, and a grease-like ink backflow preventive body 7 is contained in contact with the rear end of the ink 6 toward the tail plug 5 side. In this embodiment, the coupling member 4 with the ballpoint pen tip 3 already attached thereto is press-fitted into one end of the ink reservoir 2, but a ballpoint pen refill 1 in which the ballpoint pen tip 3 is attached directly to the front end of the ink reservoir 2 without using the coupling member 4 can also be suitably used.

[0019] For the sake of convenience, the ballpoint pen refills 1 shown in FIGS. 1 and 2 as (A), (B), and (C) will be referred to as the first refill, second refill, and third refill, respectively. In the first to third refills, the writing balls 3a, 3b, and 3c provided at the tip of each ballpoint pen tip 3 have ball diameters of 1.0 mm, 0.7 mm, and 0.5 mm, respectively, and therefore ballpoint pen tips 3 set to different ink flow rates are used. Each of the writing balls 3a, 3b, and 3c is pressed toward the tip by a coil spring 3d housed in each ballpoint pen tip 3. As a result, when no writing is being performed, the writing balls 3a, 3b, and 3c act to close the tip of the ballpoint pen tip 3.

[0020] The inner diameters of the central portions of the ink containing tubes 2 of the first to third refills are different, with the inner diameters having a relationship of d1>d2>d3 as shown in Figure 2. This allows the first to third refills 1 to be set so that the amount of ink 6 consumed along the length of the ink containing tube 2 at the same writing distance is approximately the same. The rear of the ink 6 inside the ink containing tube 2 is filled with an ink backflow preventive material, and the viscosity of this ink backflow preventive material varies depending on the inner diameter (d1, d2, d3) of the ink containing tube 2. Specific examples are shown in Examples 1 and 2 described below. It is preferable that the viscosity of the ink backflow preventive material decreases in proportion to the inner diameter of the central part of the ink containing tube.

[0021] The ink reservoir 2 of the first to third refills 1 is molded in a straight line from a transparent or translucent polypropylene resin, and the outer diameter is the same for all of the first to third refills 1. Furthermore, the overall lengths of the first to third refills 1 are also formed to be the same. By making them the same shape, the first to third refills 1 can be housed in the same common barrel of a writing instrument.

[0022] As shown in FIG. 2, the ink containing tube 2 of the first refill has a large inner diameter d1, and therefore has connecting portions 2a and 2b at both ends that are thicker toward the axial center. Furthermore, the ink containing tube 2 of the second refill has an inner diameter d2 that is slightly smaller than the inner diameter of the ink containing tube 2 of the first refill, and therefore has connecting portions 2a and 2b at both ends that are thinner toward the axial center. Furthermore, the ink containing tube 2 of the third refill has an inner diameter d3 at both ends of the connecting portions 2a and 2b, which is the same as the inner diameter of the central portion, and is formed in a straight shape. With this configuration, the inner diameters of the connecting portions 2a, 2b formed at the ends of the ink containing tubes 2 of the first to third refills are the same, so that the ink containing tubes 2 can be fitted with the common joint member 4 and tail plug 5 without any need for a front-to-back orientation.

[0023] 2, the coupling member 4 is a cylindrical body whose front half is tapered to slightly reduce its outer diameter, and has an insertion hole 4a for the ballpoint pen tip 3 formed toward the front. An annular groove 4b is also formed toward the rear, and an ink introduction hole 4c for the ballpoint pen tip 3 is opened in the shaft portion at the center of the groove. By inserting one end (front end) of the ink containing tube 2 into the annular groove 4b, the inner and outer diameter sides of the connecting portion 2a of the ink containing tube 2 are press-fitted between the inner and outer surfaces of the annular groove 4b of the coupling member 4. This increases the attachment strength.

[0024] FIG. 3 shows the individual structure of the tail plug 5 attached to the other end (rear end) of the first to third refills 1. The front half of this tail plug 5 forms a cylindrical section 5a, the axial hole of which forms an air vent 5b, and the central part is formed with a stepped section 5c of enlarged diameter. The rear half, whose diameter is enlarged by the stepped section 5c, is formed with three legs 5d divided along the circumference, each of equal length along the axial direction, and the tail end of each leg 5d is formed with an arc-shaped inclined surface 5e that slopes outward from the circumference. The tail plug 5 is preferably made of a resin material.

[0025] The tail plug 5 is attached to the ink reservoir 2 by inserting the cylindrical portion 5a into the connecting portion 2b at the rear end of the ink reservoir 2. In this case, the position of the tail plug 5 relative to the ink reservoir 2 is achieved by the step portion 5c coming into contact with the rear end of the ink reservoir 2. In this state, the air vent 5b provided in the tail plug 5 functions to exchange air as the ink in the ink reservoir 2 decreases. In addition, the leg 5d of the tail plug 5 and the inclined surface 5e formed at its tail end have flexibility that causes the leg 5d to bend inward when subjected to strong writing loads or the impact of being dropped when the ballpoint pen refill 1 is stored in the barrel tube described below.

[0026] In the first to third refills 1 described above, when achromatic ink such as black is used, as will be explained later, the greater the ink consumption, the different the hue (lower the brightness) of the ink from the ink containing tube 2. By changing the gradation of the hue in this way, in a group of ballpoint pen refills arranged in the same type of barrel, it is possible to easily and intuitively judge the difference in ball diameter and instantly pick up (select) the ballpoint refill without having to remove the tip or tail cap of the tiny ballpoint pen tip and check the cross section of the ink reservoir tube from the rear end.

[0027] In addition, the first to third refills 1 described above are designed to be used by visually impaired users who have difficulty distinguishing between hues, and as shown in Figure 1, an engraving 2c is made inside the ink reservoir 2 between the ink backflow prevention body 7 and the tail plug 5, making it easier to distinguish between the first to third refills. That is, in this embodiment, the first refill has two markings 2c that are perpendicular to the axis, the second refill has one marking 2c that is perpendicular to the axis, and the third refill has no markings.

[0028] <Refill group brightness (hue)> Next, the refills constituting the group of ballpoint pen refills were divided according to the amount of ink consumed per unit writing distance, and various characteristics including the lightness (hue) of each were measured.

[0029] To measure the brightness, five refills with the same ball diameter were attached to white fine paper conforming to JIS P3201, and the brightness value L* was measured from the surface of components such as the ink reservoir tube using a device such as a color meter (SC-P, manufactured by Suga Test Instruments Co., Ltd.). The measurement conditions when using the color meter (SC-P, manufactured by Suga Test Instruments Co., Ltd.) in the above embodiment are as follows. [Optical conditions] Reflection measurement: Diffuse light illumination, 8° reception (compliant with JIS Z 8722 condition c), trap: de: 8° (specular reflection component not included), measurement hole: φ15 mm [Light source field of view] D65 / 2 [Color system] L*a*b*c* [Stability]ΔE*ab <0.01 [Light source] VI-LED (high color rendering white LED)

[0030] Example 1 Measurements were taken on five of each of two types of writing refills (ballpoint pen refills) with different ink consumption per unit writing distance, and the results are shown in Table 1. The measured values ​​for ink consumption, viscosity of the backflow preventer, and brightness are average values.

[0031] [Table 1]

[0032] Example 2 Measurements were conducted on five of each of three types of writing refills (ballpoint pen refills) with different ink consumption per unit writing distance. The results are shown in Table 2. The measured values ​​for ink consumption, viscosity of the backflow preventer, and brightness are average values. The ballpoint pen refills shown in this embodiment correspond to the first to third refills described with reference to FIGS.

[0033] [Table 2]

[0034] In both Examples 1 and 2, inks of the same type and hue (black) with the following composition were used. Carbon black #25 (Mitsubishi Chemical): 10% by weight Polyvinyl butyral (BL-S, manufactured by Sekisui Chemical): 5% by weight Terpene phenol resin (YP90L, manufactured by Yasuhara Chemical): 8% by weight Polypropylene glycol (average molecular weight: 4000): 5% by weight Phosphate ester (Plysurf A208B): 1.47% by weight Amine compound (polyoxyethylene alkylamine: AMIET105): 1.03% by weight 3-Methoxybutanol: 5% by weight 3-Methoxy-3-methyl-1-butanol: 64.5% by weight The viscosity of the backflow preventer was measured at a shear rate of 3.8 / s in an environment of 25°C.

[0035] From Tables 1 and 2, it can be seen that the lightness (L*) changes depending on the amount of ink consumed per unit writing distance of each writing refill, that is, the thickness of the ink reservoir 2 in this embodiment. Furthermore, in each example, the difference in brightness value fell within a range that satisfied the requirement of the difference in thickness (mm) of the ink containing tube 2 x 10 or more, and it was confirmed that there was a difference in the relative numerical values, and that the change in gradation was clearly identifiable even with the naked eye.

[0036] The above measurement results show the results when ink of the same type and black hue (achromatic color) is used, but when color inks of different hues, such as red, green, and blue, are used, it is recognized that the color difference changes similarly depending on the thickness of the ink reservoir tube within the range of ink of the same type and hue. This confirms that it is possible to easily select the desired writing refill based on differences in color difference.

[0037] <Ink composition> Preferred ink compositions for use in each ballpoint pen refill of the writing refill group according to the present invention include those shown below.

[0038] The ink used in each of the ballpoint pen refills is a black ink whose main solvent (50% by weight or more of the total solvents) is a solvent selected from alcohols, polyhydric alcohols, and glycol ethers, whose vapor pressure at 25°C is 0.001 mmHg or more. The use of a specific solvent with such a high vapor pressure makes it possible to provide an oil-based ballpoint pen with an excellent, smooth writing feel. The ink composition was developed with the aim of solving the problems that are unique to the use of such specific solvents with high vapor pressures. A main solvent is one that contains 50% by weight or more of the total solvents.

[0039] Specific examples of alcohols include aliphatic alcohols having two or more carbon atoms, such as ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butyl alcohol, 1-pentanol, isoamyl alcohol, sec-amyl alcohol, 3-pentanol, tert-amyl alcohol, n-hexanol, methylamyl alcohol, 2-ethylbutanol, n-heptanol, 2-heptanol, 3-heptanol, n-octanol, 2-octanol, 2-ethylhexanol, 3,5,5-trimethylhexanol, nonanol, n-decanol, undecanol, n-decanol, trimethylnonyl alcohol, tetradecanol, heptadecanol, cyclohexanol, 2-methylcyclohexanol, benzyl alcohol, and many other higher alcohols.

[0040] Examples of polyhydric alcohols include polyhydric alcohols having two or more carbon atoms and two or more hydroxyl groups in the molecule, such as ethylene glycol, diethylene glycol, 3-methyl-1,3-butanediol, triethylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,5-pentanediol, hexylene glycol, and octylene glycol.

[0041] Examples of glycol ethers include methyl isopropyl ether, ethyl ether, ethyl propyl ether, ethyl butyl ether, isopropyl ether, butyl ether, hexyl ether, 2-ethylhexyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and tetraethylene glycol monobutyl ether. ether, 3-methyl-3-methoxy-1-butanol, 3-methoxy-1-butanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol phenyl ether, propylene glycol tert-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, and tetrapropylene glycol monobutyl ether.

[0042] Among the solvents listed above, glycol ethers having 2 to 7 carbon atoms are particularly preferred, as their effects are particularly clear. From the standpoint of safety and oral toxicity, it is also preferable to use organic solvents other than ethylene glycol derivatives. In addition to the solvents listed above, the following solvents may be added to the mixture of phosphoric acid ester and amine compound within a range that does not impair the solubility of the mixture and the performance of the mixture. Examples of such derivatives include polyhydric alcohol derivatives, such as sorbitan fatty acid derivatives, polyglycerin higher fatty acid derivatives, sucrose fatty acid derivatives, and propylene glycol fatty acid derivatives.

[0043] Examples of ester solvents include propylene glycol methyl ether acetate, propylene glycol diacetate, 3-methyl-3-methoxybutyl acetate, propylene glycol ethyl ether acetate, ethylene glycol ethyl ether acetate, butyl formate, isobutyl formate, isoamyl formate, propyl acetate, butyl acetate, isopropyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, propyl propionate, isobutyl propionate, isoamyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, methyl isobutyrate, ethyl isobutyrate, propyl isobutyrate, Examples of the esters include methyl valerate, ethyl valerate, propyl valerate, methyl isovalerate, ethyl isovalerate, propyl isovalerate, methyl trimethylacetate, ethyl trimethylacetate, propyl trimethylacetate, methyl caproate, ethyl caproate, propyl caproate, methyl caprylate, ethyl caprylate, propyl caprylate, methyl laurate, ethyl laurate, methyl oleate, ethyl oleate, caprylic triglyceride, tributyl acetate citrate, octyl oxystearate, propylene glycol monoricinoleate, methyl 2-hydroxyisobutyrate, and 3-methoxybutyl acetate.

[0044] Specific examples of diether and diester solvents having no hydroxyl group in the molecule include ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, and dipropylene glycol dimethyl ether.

[0045] The colorant (coloring material) is not limited, but is preferably a pigment or a combination of a pigment and a dye. The use of a pigment has the effect of providing excellent fastness. Examples of pigments that can be used include carbon black, phthalocyanine-based pigments, and organic pigments such as azo-based pigments including insoluble azo-based pigments such as monoazo, disazo, condensed azo, and chelate azo-based pigments, and soluble azo-based pigments such as sparingly soluble azo-based pigments and soluble azo-based pigments, as well as quinacridone-based pigments, diketopyrrolopyrrole-based pigments, threne-based pigments, dioxazine-based pigments, and isoindolinone-based pigments.

[0046] In particular, carbon black should be used with as small a specific surface area as possible, with a value measured by the BET method of 100m 2 Specifically, carbon black manufactured by Mitsubishi Chemical Corporation includes #33, #32, #30, #25, and CF9, carbon black manufactured by Cabot Corporation includes REGAL (400R, 500R, 330R, and 300R), ELFTEX (8 and 12), and STERLING R, carbon black manufactured by Degussa Corporation includes Printex (45, 40, 300, 30, 3, 35, 25, 200, A and G), and SB (250 and 200), and carbon black manufactured by Columbian Corporation includes RAVEN (1040, 1035, 1020, 1000, 890, 890H, 850, 500, 450, 420, 410, H20, 22, 16, and 14).

[0047] The pigment is preferably one that is difficult to dissolve in the organic solvent used and has an average particle size of 30 nm to 700 nm after dispersion. The amount of pigment to be blended is 0.5 to 25% by weight, preferably 0.5 to 20% by weight, based on the total weight of the ink composition, as needed.

[0048] Pigments can be used alone or in combination of two or more. If necessary, inorganic pigment dispersions or dyes can also be added to the extent that they do not adversely affect dispersion stability. The use of dyes has the effect of improving color development. Other examples include resin emulsions obtained by polymerizing styrene, acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, acrylonitrile, and olefin-based monomers; hollow resin emulsions that swell and become amorphous in ink; and organic multicolor pigments made of dyed resin particles obtained by dyeing these emulsions themselves with a colorant.

[0049] When the colorant used in this embodiment is a pigment, various conventionally known methods can be used to produce the pigment dispersion ink composition. For example, the pigment dispersion ink composition can be easily obtained by blending the above-mentioned components and mixing and stirring them with a stirrer such as a dissolver, or by mixing and grinding them with a ball mill, roll mill, bead mill, sand mill, pin mill, or the like, and then removing coarse pigment particles, undissolved matter, and contaminating solid matter by centrifugation or filtration.

[0050] Dyes used in combination with these pigments can be used without any particular limitation as long as they do not destroy the dispersion system. Examples of such dyes include direct dyes, acid dyes, basic dyes, mordant and acid mordant dyes, alcohol-soluble dyes, azoic dyes, sulfide and sulfide vat dyes, vat dyes, disperse dyes, oil-soluble dyes, food dyes, and metal complex dyes, all of which are commonly used in dye ink compositions, as well as inorganic and organic pigments commonly used in pigment ink compositions. The amount of dye used is selected from the range of 1 to 50% by weight based on the total weight of the composition.

[0051] Resins are used in oil-based ink compositions. Resins used in oil-based ink compositions are added for purposes such as viscosity adjustment and improvement of pen tip wear, and when a pigment is included, they are also used as dispersants. Examples of such resins include ketone resins, styrene resins, styrene-acrylic resins, terpene phenol resins, rosin-modified maleic acid resins, rosin phenol resins, alkylphenol resins, phenolic resins, styrene-maleic acid resins, rosin-based resins, acrylic resins, urea aldehyde-based resins, maleic acid-based resins, cyclohexanone-based resins, polyvinyl butyral, polyvinyl pyrrolidone, and the like.

[0052] The blending amount of these resins is preferably 1 to 30% by weight, more preferably 1 to 20% by weight. If the blending amount is less than 1% by weight, it becomes difficult to adjust the viscosity and prevent wear at the pen tip, while if it exceeds 30% by weight, it becomes impossible to blend raw materials other than the resin, and it may have a negative impact on the writing feel.

[0053] In a preferred embodiment, when a pigment is used as the colorant of the ink composition, the dispersant used can be selected from the resins listed above that can disperse the pigment, and any surfactant or oligomer can be used as long as it suits the purpose. Specific examples of dispersants include synthetic resins such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl butyral, polyvinyl ether, styrene-maleic acid copolymer, ketone resin, hydroxyethyl cellulose and its derivatives, and styrene-acrylic acid copolymer, as well as PO·EO adducts and polyester amine oligomers.

[0054] When the ink is an oil-based ink composition, it contains a neutralized phosphate ester, which has the effect of facilitating the removal of ink deposits on the ball surface, thereby preventing smearing of the writing when the ink starts to be written, and in this embodiment, works in conjunction with polypropylene glycol to prevent smearing of the writing when the ink starts to be written for a short or long period of time, and also has the effect of smoothing the ink transfer when writing at a low speed.

[0055] The phosphate esters used are typically composed of phosphate monoesters, diesters, and trace amounts of triesters, and most surfactants have two types of ester structures: aromatic and aliphatic. Regarding the alkyl groups capable of forming the phosphate ester structure, alkyl groups derived from natural or synthetic higher alcohols are used. Phosphate esters having an alkyl group with 10 to 20 carbon atoms and a polyoxyethylene chain with 0 to 50 carbon atoms are used. Phosphate esters having an alkyl group with 15 to 20 carbon atoms and a polyoxyethylene chain with 0 to 4 carbon atoms are particularly preferred. Furthermore, neutralization with an amine-based compound such as alkanolamine, polyoxyethylene alkylamine, amphoteric surfactant, or fatty amine is preferred.

[0056] The amount of these additives added is preferably 0.01 to 15% by weight, more preferably 0.1 to 10% by weight, based on the total weight of the ink composition as a neutralized mixture. An amount of 0.1 to 8% by weight is particularly preferred. If the amount is less than 0.01% by weight, the effect of facilitating the removal of ink deposits from the ball surface is reduced. If the amount is more than 15% by weight, the ink may be repelled too much by the ball, resulting in poor line quality and other problems, such as line breakage.

[0057] When the ink is an oil-based ink composition, it is desirable to add polypropylene glycol. The addition has the effect of preventing smearing when starting to write. This phenomenon not only prevents smearing achieved by ink repellency on the metal ball, but also makes it more difficult for an ink film to form, making it possible to prevent smearing even in a short period of 1 to 20 minutes.

[0058] The molecular weight of polypropylene glycol is preferably as large as possible, since this allows for a smaller amount to be added and improves the drying properties of drawn lines. The molecular weight (calculated molecular weight) is preferably 1,000 or more, more preferably 2,000 or more, and even more preferably 4,000 or more.

[0059] The amount of polypropylene glycol added is preferably 0.01 to 10% by weight, and particularly preferably 0.1 to 10% by weight. In this range, pigment-based inks that dry easily become less likely to form an ink film on the metal ball, which is highly effective in preventing smearing when starting to write.

[0060] Outside this range, if the amount is less than 0.1% by weight, the effect will be poor and the ball may not spin, and if it exceeds 10% by weight, the amount of non-volatile components in the ink will increase, which may reduce the drying speed of the drawn lines or make them more susceptible to bleed-through, depending on the raw materials used.

[0061] Furthermore, in this embodiment, if necessary, anti-rust agents, anti-fungal agents, surfactants, lubricants, wetting agents, and the like that are compatible with the ink and do not adversely affect the ink may be blended. Fatty acids, in particular, are preferably used as lubricants. Furthermore, non-volatile solvents that are compatible with the main solvent and do not adversely affect the product characteristics may also be blended as drying suppression additives.

[0062] <Writing Instruments (Ballpoint Pens)> Next, Figures 4 and 5 show an example of a writing instrument (ballpoint pen writing instrument) in which one writing refill (ballpoint pen refill) 1 from the ballpoint pen refill group described above is housed in a barrel, and in this example, the first refill 1 shown in Figure 1(A) is used. The barrel 12 constituting the writing instrument 11 shown in Figures 4 and 5 is formed by molding a sheet of synthetic resin, such as polycarbonate, polypropylene, or polyethylene terephthalate. That is, a repeating pattern of multiple recesses and protrusions is formed on both sides of the sheet, and the barrel 12 is formed by welding both ends of the sheet so that the entire body is cylindrical. Then, a front joint 13 and a rear joint 14, each made of a resin material and cylindrically shaped, are attached to both ends of the barrel 12.

[0063] The barrel 12 is formed by another manufacturing method in which a cylindrically formed sheet material is strongly sandwiched between two rollers having predetermined irregularities and disposed inside and outside the cylinder with an axis parallel to the cylinder, thereby forming creases. The barrel 12 may also be formed by blow molding. The wall thickness of the formed barrel 12 is preferably less than 1 mm, and a wall thickness of 0.35 mm, for example, is also practical. In addition, since the barrel 12 is manufactured from sheet material, the wall thickness of the barrel 2 is approximately uniform overall. The barrel 12 is connected to the front joint 13 and the rear joint 14 by, for example, adhesion or welding.

[0064] The barrel 12 described above is less likely to deform and has higher rigidity than a barrel formed into a cylindrical shape with the same thickness and no irregularities, in response to the force applied in the direction of the central axis when the user grips it. Furthermore, the barrel 12 is thinner and lighter than a barrel formed into a cylindrical shape with no irregularities so as to have the same rigidity against the force applied in the direction of the central axis when the user grips it. Furthermore, the barrel 12 has a regularly irregular outer surface formed by a combination of three-dimensional polygonal unit patterns, which also provides a decorative effect.

[0065] A conical tip portion 15 is detachably attached by a screw connection using a front joint 13 attached to the barrel 12. An opening 15a is provided at the tip of this tip portion 15, and the writing portion (ballpoint pen tip) 3 of the ballpoint pen refill 1 appears and disappears from the tip opening 15a by a knock operation described later. A cylindrical member 16 is attached using a joint 14 attached to the barrel 12, and a clip 16a is formed integrally with the cylindrical member 16. A knock operation portion 17 is disposed at the rear end of the cylindrical member 16 in a protruding state.

[0066] 5(C) shows this writing instrument 11 in a cross section along the axial direction, with a coil-shaped return spring 18 attached inside the tip portion 15. Therefore, by removing the tip portion 15 from the front joint 13, storing the ballpoint pen refill 1 inside the barrel 12, and screwing the tip portion 15 onto the front joint 13, the return spring 18 comes into contact with the joint member 4 of the ballpoint pen refill 1. As a result, a biasing force is applied to the ballpoint pen refill 1 by the return spring 18 in the direction toward the rear end within the barrel 12 .

[0067] Furthermore, a rotor 19 is mounted inside the cylindrical member 16, and a truncated cone-shaped recess 19a having a slope that reduces the inner diameter toward the bottom is formed at the front end of the rotor 19, and the tail plug 5 of the ballpoint pen refill 1 is inserted and positioned inside this recess 19a. On the other hand, the knock operating unit 17 is arranged to cover the shaft extending to the rear of the rotor 19, and the rotor 19 and the knock operating unit 17 are arranged in a retracted position by the force of the return spring 18 via the ballpoint pen refill 1. Therefore, by knocking the knock operation portion 17, the rotor 19 and the ballpoint pen refill 1 move forward in the axial direction against the biasing force of the return spring 18.

[0068] A cam member consisting of multiple ribs along the axial direction is formed within the cylindrical member 16, and together with the rotor 19 that abuts against this cam member, a rotary payout mechanism known as a knock mechanism is formed. As a result, each time the knock operation unit 17 is operated, the ballpoint pen refill 1 moves forward together with the rotor 19, and the ballpoint pen tip 3 as the writing part is repeatedly set in a writable state in which it protrudes from the tip opening 15a, and the ballpoint pen refill 1 moves back together with the rotor 19, and the ballpoint pen tip 3 is stored in the tip opening 15a.

[0069] In addition, when the ballpoint pen tip 3 is in a writable state protruding from the tip opening 15a of the mouth part 15, the tail plug 5 is inserted into the truncated cone-shaped recess 19a of the rotor 19. When a writing load is applied in this state, the inclined surfaces 5e formed on the legs 5d of the tail plug 5 come into contact with the inclined surfaces of the truncated cone-shaped recesses 19a provided on the rotor 19, acting to deflect each leg 5d in the axial direction. This provides a cushioning effect to the ballpoint pen refill 1 in the axial direction. Therefore, it is possible to easily absorb the vertical load applied during writing, and to prevent deformation (buckling or bending) of the thin-walled ink reservoir tube 2.

[0070] According to the writing implement described above, the thickness of the barrel 12 can be made thinner than before, so that the writing refill 1 can be seen through the barrel 12 to some extent. Therefore, by creating a group (set) of writing implements that employs a combination of different barrel thicknesses 12 according to the ink consumption per unit writing distance of the writing refills 1 housed in the barrel 12, the differences in appearance visibility between the writing refill groups can be further emphasized. [Explanation of symbols]

[0071] 1 writing refill (ballpoint pen refill) 2 Ink reservoir tube 3 Writing part (ballpoint pen tip) 3a~3c Writing ball 4 Joint members 5 tail plug 6. Ink 7 Ink backflow prevention body 11 Writing instruments 12 shaft cylinder 13 Front joint 14 Successor 15 Mouth 16 Cylindrical member 17 Knock parts 18 Return spring 19 Rotor

Claims

[Claim 1] A group of writing refills in which a coupling member supporting a writing part is attached to one end of a transparent or translucent ink reservoir tube, and ink is contained within the ink reservoir tube, wherein, among the components of the writing refill, the coupling member and the tail plug attached to the other end of the ink reservoir tube are the same, and the outer diameter of the ink reservoir tube and the overall length of the writing refill are the same, A group of writing refills characterized in that the ink containing tubes contain ink of the same hue, and the color difference of each ink containing tube is made different by varying the inner diameter of the ink containing tubes according to the amount of ink consumed per unit writing distance of the writing refill.

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