Notebook

Abstract

To provide a writing implement capable of drawing a line by using capillary force, capable of freely adjusting the width of the line while drawing the line, and capable of drawing a line of almost the same width at the beginning and end of use of the writing implement. [Solution] The felt-tip pen 1 comprises an ink storage section 11, a collector 17, and a core 29 that uses capillary force to suck up the ink delivered by the collector 17, delivers the sucked ink from the tip, and deposits it on the paper surface; even with repeated writing, the rate of change in the width of the line drawn at the end of use compared to the width of the line drawn at the beginning of use is 10% or less.

Description

[Technical Field]

[0001] The present invention relates to a writing instrument, and more particularly to a writing instrument, such as a felt-tip pen or a marking pen, that is capable of drawing lines using capillary force. [Background technology]

[0002] BACKGROUND ART Ballpoint pens that are capable of changing the width of a drawn line have been known (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-252654 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-252655 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the devices described in Patent Documents 1 and 2 relate to ballpoint pens. However, due to their structure, ballpoint pens are limited in the thickness of the lines they can draw, and there is a demand for writing implements that can change the width of lines while drawing relatively thick lines.

[0005] Furthermore, in general, with writing implements that draw lines using capillary force, such as felt-tip pens or marking pens, there is a difference in the width of the line drawn between the beginning and end of use of the writing implement.

[0006] Therefore, the present invention aims to provide a writing instrument that can draw lines using capillary force, in which the width of the line can be freely adjusted while drawing the line, and which can draw lines of approximately the same width at the beginning and end of use of the writing instrument. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a writing instrument comprising an ink storage section that stores ink, an air replacement mechanism that sends out ink from the ink storage section by sending air into the ink storage section, and a core that uses capillary force to suck in the ink sent out by the air replacement mechanism, sends the sucked ink from the tip, and deposits it on the paper surface, wherein the rate of change in line width before and after writing is 10% or less when writing repeatedly alternately with a writing weight of 50g and a writing weight of 200g.

[0008] In the present invention configured as described above, it is preferable that the ratio of the width of the line that can be drawn under writing conditions of a writing angle of 60 degrees and a writing weight of 200 g to the width of the line that can be drawn under writing conditions of a writing angle of 90 degrees and a writing weight of 50 g is 1.5 or more, and more preferably 2.0.

[0009] In the present invention configured as described above, the elastic limit of the writing part including the core is preferably 7.0 N or more, and more preferably 9.8 N or more. By making it 7.0 N or more, damage to the writing part can be prevented even when a person applies force to the writing part when writing.

[0010] Furthermore, in the present invention configured as described above, the buckling strength of the writing part including the core is preferably 7.0 N or more, and more preferably 9.8 N or more. By making it 7.0 N or more, damage to the writing part can be prevented even when a person applies force to the writing part when writing.

[0011] Furthermore, in the present invention configured as described above, it is preferable that the amount of wear of the writing part 13 when drawing a 100 m line is 0.3 mm or less. Since the amount of wear is 0.3 mm or less, writing can be continued comfortably until the ink runs out even for long writing distances.

[0012] In the present invention configured as described above, the writing flow rate per unit area is 5 g / m 2 It is preferable that the writing flow rate per unit area is 5 g / m or more. 2By doing so, it is possible to prevent the phenomenon of fading or cutting of the drawn lines during writing.

[0013] Furthermore, it is preferable that the set load applied to the writing part, including the core, when the writing part begins to sink relatively into the barrel due to pressure, is 0.1 N or more and 7.0 N or less.

[0014] The cushioning force refers to the vertical load applied to the writing part when the writing part begins to sink relatively into the barrel due to axial compression or pressure during writing. By setting the cushioning force to between 0.1N and 7.0N, it is possible to prevent the writing part from breaking or collapsing even when a large writing load is applied to the writing part. [Effects of the Invention]

[0015] As described above, according to the present invention, the width of the line can be freely adjusted while drawing the line, and the line can be drawn with approximately the same width at the beginning and end of use. [Brief explanation of the drawings]

[0016] [Figure 1] 1 shows a felt-tip pen according to an embodiment of the present invention, more specifically, FIG. 1(a) and FIG. 1(b) show the state in which the front of the felt-tip pen is covered by a cap, and FIG. 1(c) shows a cross-sectional view of the state in FIG. 1(b). [Figure 2] FIG. 1(c) is an enlarged view of a main part of FIG. [Figure 3] Longitudinal cross-sectional view of the core [Figure 4] FIG. 4 shows a view of the collector from three directions. [Figure 5] 5 shows a perspective view, a side view, and a cross-sectional view of a joint; FIG. [Figure 6] 6A and 6B are drawings showing the outer, specifically, FIG. 6A shows a perspective view, a side view, and a cross-sectional view of the outer. [Figure 7]FIG. 10 is a cross-sectional view showing a modified example of the core. [Figure 8] FIG. 10 is a cross-sectional view showing a further modified example of the core. [Figure 9] FIG. 10 is a perspective view showing a modified example of the outer. [Figure 10] FIG. 10 is a cross-sectional view showing another modified example of the outer. [Figure 11] FIG. 10 is a side cross-sectional view showing a modified example of the inner cap. [Figure 12] FIG. 10 is a side cross-sectional view showing a modified example of the ink holding portion. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, a felt-tip pen according to an embodiment of the present invention will be described with reference to the drawings. In this specification, the "front" of the felt-tip pen and its components refers to the side where the core is provided in the axial direction of the felt-tip pen, and the "rear" refers to the opposite side.

[0018] Fig. 1 shows a felt-tip pen according to an embodiment of the present invention, more specifically, Fig. 1(a) and Fig. 1(b) show the state in which the front of the felt-tip pen is covered with a cap, Fig. 1(c) shows a cross-sectional view of the state in Fig. 1(b), and Fig. 2 shows an enlarged view of the main part of Fig. 1(c).

[0019] As shown in FIGS. 1 and 2, the felt-tip pen 1 includes a body 3 of the felt-tip pen and a cap 5 attached to the body 3.

[0020] The body 3 of the felt-tip pen has an overall cylindrical shape so that it can be gripped by a user during use. It includes a front barrel 7 and a rear barrel 9. The rear end of the front barrel 7 and the front end of the rear barrel 9 are each provided with a screw thread, and the front barrel 7 and the rear barrel 9 are fixed to each other by screwing them together. By screwing and fixing the front barrel 7 and the rear barrel 9 together, a space is formed inside to accommodate the various components used for writing with the felt-tip pen. The front barrel 7 and the rear barrel 9 may also be fixed by press-fitting rather than by screwing. In this case, the press-fit force is preferably 300 N or less to prevent damage to the outer casing 31 due to impact during assembly. In the following description, the space formed inside the front barrel 7 and the rear barrel 9 will be referred to simply as the "internal space."

[0021] The cap 5 is configured to be removably attached to the front side of the body 3 of the felt-tip pen, and prevents the ink from drying out by sealing the tip of the felt-tip pen. The cap 5 includes an inner cap 5c and a fitting portion 5b. The inner cap 5c is configured to fit into the body 3 so as to completely enclose the outer casing 31 and the core 29 of the felt-tip pen, which will be described later. The cap 5 itself is removably attached to the body 3 via the fitting portion 5b with a predetermined fitting force, for example, a fitting force of 60 N or less. Setting the fitting force of the cap 5 to 60 N or less prevents the outer casing 31 from being damaged by the impact when attaching the cap 5.

[0022] An ink storage section 11 for storing ink is located at the rear side of the internal space, and a writing section 13 for writing using the ink in the ink storage section 11 is located at the front side of the internal space.Furthermore, an ink supply section 15 is provided between the ink storage section 11 and the writing section 13 for supplying the ink in the ink storage section 11 to the writing section 13.

[0023] The ink storage section 11 stores a predetermined amount of ink therein, and is configured so that when the ink in the writing section 13 runs low, ink can be supplied to the writing section 13 as needed by capillary force.

[0024] Either a pigment or a dye may be used as the coloring material for the ink contained in the ink container 11. There are no particular restrictions on the type of pigment, and any inorganic or organic pigment that has been conventionally used for writing instruments such as water-based ballpoint pens may be used.

[0025] Examples of inorganic pigments include carbon black and metal powder. Examples of organic pigments include azo lakes, insoluble azo pigments, chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dye lakes, nitro pigments, and nitroso pigments. Specific examples include phthalocyanine blue (CI 74160), phthalocyanine green (CI 74260), Hansa yellow 3G (CI 11670), disazo yellow GR (CI 21100), permanent red 4R (CI 12335), brilliant carmine 6B (CI 15850), and quinacridone red (CI 46500).

[0026] Plastic pigments composed of styrene or acrylic resin particles may also be used. Furthermore, hollow resin particles with voids inside the particles can be used as white pigments, or pigments called pseudopigments in which resin particles are dyed with dyes. Specific product names for pseudopigments include the Shinroihi Color SF series (Shinroihi Co., Ltd.), and the NKW and NKP series (Nippon Fluorescent Chemical Co., Ltd.).

[0027] The water-soluble dyes may be direct dyes, acid dyes, food dyes, or basic dyes. Examples of direct dyes include CI Direct Black 17, 19, 22, 32, 38, 51, and 71, CI Direct Yellow 4, 26, 44, and 50, CI Direct Red 1, 4, 23, 31, 37, 39, 75, 80, 81, 83, 225, 226, and 227, and CI Direct Blue 1, 15, 71, 86, 106, and 119.

[0028] Examples of acid dyes include CI Acid Black 1, 2, 24, 26, 31, 52, 107, 109, 110, 119, and 154; CI Acid Yellow 7, 17, 19, 23, 25, 29, 38, 42, 49, 61, 72, 78, 110, 127, 135, 141, and 142; CI Acid Red 8, 9, 14, 18, 26, 27, 35, 37, 51, and 52; Examples include CI 57, CI 82, CI 87, CI 92, CI 94, CI 115, CI 129, CI 131, CI 186, CI 249, CI 254, CI 265, CI 276, CI Acid Violet 18, CI 17, CI Acid Blue 1, CI 7, CI 9, CI 22, CI 23, CI 25, CI 40, CI 41, CI 43, CI 62, CI 78, CI 83, CI 90, CI 93, CI 103, CI 112, CI 113, CI 158, CI Acid Green 3, CI 9, CI 16, CI 25, and CI 27.

[0029] Most food dyes are classified as direct dyes or acid dyes, but an example of a dye that is not classified as food dyes is CI Food Yellow 3.

[0030] Examples of basic dyes include CI Basic Yellow 1, 2, 21, CI Basic Orange 2, 14, 32, CI Basic Red 1, 2, 9, 14, CI Basic Brown 12, Basic Black 2, 8, and the like.

[0031] These colorants may be used alone or in combination of two or more kinds, and the content of the colorant in the ink is usually in the range of 0.5 to 30% by weight, preferably 1 to 15%.

[0032] If the content of the colorant is less than 0.5%, the coloring power will be insufficient, which is not preferred, whereas if the content of the colorant is more than 30%, poor writing may occur, which is not preferred.

[0033] When dyes are used, ink adhering to the writing part 13 tends to remain as stains, so it is preferable to use pigments.

[0034] Furthermore, to prevent poor writing due to the ink drying and solidifying at the pen tip, it is preferable that the content of the water-soluble solvent in the ink be 1% to 25% by weight. In this case, examples of the water-soluble solvent that can be used include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 3-butylene glycol, thiodiethylene glycol, and glycerin, as well as ethylene glycol monomethyl ether and diethylene glycol monomethyl ether, either alone or in combination.

[0035] In addition to the above, it is preferable to add at least one water-soluble solvent selected from trimethylolpropane, trimethylolethane, and neopentyl glycol in an amount of 0.1 to 5% by weight based on the ink.

[0036] Generally, as the amount of water-soluble solvent increases, the ink's ability to penetrate paper decreases, slowing the drying speed of drawn lines. However, trimethylolpropane, trimethylolethane, and neopentyl glycol have little effect on reducing penetration, making them extremely unlikely to cause delays in the drying speed of drawn lines. On the other hand, they have the property of preventing the pen tip from drying and solidifying, so writing defects are unlikely to occur even if the pen tip is exposed to light for long periods of time.

[0037] Sugars can be blended into the ink. Specific examples of sugars include monosaccharides, disaccharides, oligosaccharides, reducing sugars, non-reducing sugars, sugar alcohols, reduced starch hydrolysates, and mixtures thereof. Of these, non-reducing sugars, particularly sugar alcohols, are preferred. Sugars with reducing properties can cause discoloration of the ink or fluctuations in pH.

[0038] The non-reducing sugars are not particularly limited as long as they are sugars that do not exhibit reducing properties, and examples thereof include sucrose, trehalose, sugar alcohols, etc. Reducing sugars such as glucose (grape sugar) are sugars that exhibit weak reduction due to the presence of a carbonyl group (reducing group) such as an aldehyde group or a ketone group in the molecule, whereas the non-reducing sugars used in this embodiment do not exhibit reducing properties because the reducing group of the monosaccharide is bonded to another sugar via a glycosidic bond or the like.

[0039] Sugar alcohol is a general term for chain polyhydric alcohols obtained by reducing (hydrogenating) the carbonyl groups of sugars. Examples of sugar alcohols include "sorbitol" obtained by reducing glucose, "maltitol" obtained by reducing maltose, reduced starch hydrolysates (reduced starch syrup) obtained by reducing starch syrup or dextrin with different degrees of saccharification, reduced dextrin, erythritol, and pentaerythritol, and these can be used as commercially available products.

[0040] Among these non-reducing sugars, it is desirable to use at least one selected from sorbitol, erythritol, pentaerythritol, trehalose, and reduced starch hydrolysates in terms of further stability over time.

[0041] Sugars act as humectants in ink, but also have the property of forming a film and easily solidifying. In this embodiment, if ink remaining in the writing portion 13 forms a film and solidifies, the ink will be difficult to flow out the next time the ink starts writing (poor initial writing performance). To avoid this problem, the sugars contained in the ink preferably have a degree of polymerization of monosaccharides to 20 sugars, and more preferably an average degree of polymerization of 3 to 10. This prevents the film from becoming too strong, and ensures initial writing performance even when ink remains in the writing portion 13.

[0042] Moisturizing agents other than the sugars mentioned above include urea, ethylene urea, tetramethyl urea, thiourea, ethylene oxide adducts of urea, trimethylglycine, pyrophosphates, and pyrrolidones. These moisturizing agents can be used in combination with the sugars.

[0043] A penetrant can be blended into the ink. The main purpose of the penetrant is to promote the penetration of the ink into the paper, thereby improving the drying speed of the drawn lines. The penetrant is preferably a surfactant, and nonionic or anionic surfactants are preferred. Specific examples of the penetrant that can be blended include polyglycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, salts of dialkyl or dialkenyl sulfosuccinic acid, phosphate esters, and fluorine-based surfactants.

[0044] Furthermore, it is preferable to select ink characteristics such that the contact angle of the ink with respect to the outer surface of the writing part 13 (described later) is 70 degrees or less after 20 seconds. If the contact angle exceeds 70 degrees, the ink will not spread sufficiently with respect to the outer surface, resulting in a decrease in the responsiveness of the second writing part and smearing of the drawn line. The contact angle is measured by dropping ink onto a plate-shaped test piece made of the same material as the outer surface in an environment of 25°C and 65% RH.

[0045] Furthermore, it is preferable to use ink with a surface tension of 48 mN / m or less. If the surface tension exceeds 48 mN / m, the ink will not be able to spread over the outer surface sufficiently, which will reduce the responsiveness of the second writing part, making the above-mentioned phenomenon more likely to occur.

[0046] Furthermore, the content of insoluble components such as pigments and resin particles in the ink is preferably 20% by weight or less. If the insoluble components exceed 20% by weight, the fluidity of the ink decreases, making it less likely for the ink to spread on the outer layer. Furthermore, the ink that adheres to the outer layer is more likely to dry and solidify, making writing defects more likely to occur.

[0047] Furthermore, the average particle size of the insoluble components contained in the ink is preferably 200 nm or less. If the average particle size exceeds 200 nm, the fluidity of the ink decreases, and the ink tends to have insufficient spreadability over the outer layer.

[0048] The ink supply unit 15 is equipped with a substantially cylindrical collector 17 having a plurality of fins formed on its outer periphery. The collector 17 replaces the ink in the ink storage unit 11 with air drawn in from the outside, thereby discharging the ink from the ink storage unit 11. The tip of the collector 17 is formed with a reduced diameter and forms a tip holder 19. The rear end of the collector 17 is in contact with the front end of the ink storage unit 11. The tip holder 19 of the collector 17 is fitted into the inside of a fitting 21 from the rear end of the fitting.

[0049] FIG. 3 is a longitudinal cross-sectional view of the core 29. The core 29 is formed by extrusion molding a resin material such as polyacetal. A passage is formed within the core 29 to guide ink in the ink storage section 11 toward the front end by capillary action. The elastic limit of the writing part 13, including the core 29, is preferably 7.0 N or greater. Furthermore, the buckling strength when a load is applied to the writing part 13 in the longitudinal direction is preferably 7.0 N or greater. Setting the elastic limit and / or buckling strength of the writing part 13 to 7.0 N allows the writing part 13 to continue writing without deformation, even when written by a person with strong writing pressure. Furthermore, the wear of the writing part 13 is preferably 0.3 mm or less when a 100-m line is drawn under the following writing conditions: a writing angle of 65 degrees, a writing weight of 50 g, and a writing speed of 4.2 m / min. Furthermore, the elastic limit, buckling strength, and wear amount can be changed by changing the porosity of the core material and the shape of the passages.

[0050] Fig. 4 is a diagram showing the collector, and shows the collector as viewed from three directions. As shown in Fig. 4, collector 17 has a storage section 17a on the front side, a dummy section 17b on the rear side, and a partition section 17c between storage section 17a and dummy section 17b.

[0051] The outer periphery of reservoir 17a is provided with ink guide groove 17d, which extends along the axis of reservoir 17a and has a predetermined width along the circumferential direction, and main ink temporary storage groove 17f, which is formed between multiple fins 17e. Furthermore, reservoir 17a is provided with hole 17g, which extends between the outer periphery of reservoir 17a and the internal space.

[0052] The ink guide groove 17d is formed by cutting out the same shape from multiple fins 17e arranged in the axial direction. When viewed axially from the reservoir 17a, the ink guide groove 17d forms a groove of a predetermined shape recessed from the outer periphery of the reservoir 17a and communicates with the main ink temporary storage groove 17f. The width of the ink guide groove 17d is narrower than the width of the main ink temporary storage groove 17f. By making the width of the ink guide groove 17d narrower than the width of the main ink temporary storage groove 17f, the interfacial tension between the ink guide groove 17d and the ink becomes stronger than the interfacial tension of the main ink temporary storage groove 17f. This allows ink to be present in the ink guide groove 17d and reliably flow into or out of the main ink temporary storage groove 17f via the ink guide groove 17d.

[0053] The ease of ink flow during writing depends on the width of the ink guide groove 17d and the spacing between the fins 17e. In this embodiment, the width of the ink guide groove 17d is preferably 0.1 to 0.2 mm. A narrower width of the ink guide groove 17d facilitates the capillary force of the collector 17, while a width of 0.1 mm or less makes the ink supply from the collector 17 unstable and makes it difficult for the ink to be discharged. The spacing between the fins 17e is determined based on the width of the ink guide groove 17d and is set to be greater than the width of the ink guide groove 17d, within the range of 0.1 to 0.6 mm. If the width between the fins 17e is greater than 0.6 mm, ink cannot be stored in the ink storage section 17a. If the width between the fins 17e is less than 0.1 mm, ink may remain in the ink storage section 17a, potentially resulting in incomplete ink use.

[0054] The outer periphery of the dummy portion 17b is provided with an ink introduction groove 17h extending in the axial direction and extended air grooves 17j formed between the multiple fins 17i. The dummy portion 17b prevents ink from flowing into the storage portion 17a of the collector 17 when the cap 5 is opened with the cap 5 facing downward. More specifically, when the cap 5 is opened with the cap 5 facing downward, the pressure inside the space at the tip that was sealed by the cap 5 is reduced, causing ink to flow into the storage portion 17a of the collector 17. By providing the dummy portion 17b on the rear side of the collector 17, ink flows between the outer periphery fins 17i of the dummy portion 17b and does not flow into the storage portion 17a of the collector 17.

[0055] Furthermore, the hole 17g of the reservoir 17 is intended to prevent ink from spurting out from the pen tip when the space inside the collector 17 and the ink storage section 11 is pressurized when the writing part 13 is moved. More specifically, by forming the hole 17g that communicates the inside and outside of the reservoir 17, even if the space inside the collector 17 and the ink storage section 11 is pressurized when the writing part 13 is moved, the ink is discharged to the outside through the hole 17g, thereby preventing the pressure inside the collector 17 and the ink storage section 11 from increasing. The opening area of ​​the hole 17g is 0.4 to 1.2 mm 2 It is preferable that:

[0056] The collector 17 also includes a rod-shaped collector wick 23 made of polyester fiber. The collector wick 23 extends axially, with its rear end slidably positioned inside the ink reservoir 11 and its front end extending beyond the joint 21. The collector wick 23 is positioned with a gap of 0.02 to 0.2 mm between it and the inner circumferential surface of the collector 17. Providing a gap of 0.02 to 0.2 mm between the collector 17 and the collector wick 23 ensures smooth sliding between them while preventing large amounts of air from entering the gap during writing. The rear end of the collector wick 23 protrudes beyond the rear end of the collector 17. To ensure both stable ink supply and ink absorption, the collector wick 23 is preferably made of a material with a porosity of 30 to 60%, and most preferably 45%.

[0057] The joint 21 is a member for connecting the writing unit 13 and the ink supply unit 15. The configuration of the joint 21 will be described later.

[0058] The writing part 13 includes a core 29 and an outer casing 31 that covers the outer periphery of the core 29.

[0059] Fig. 5 is a drawing showing the joint, specifically showing a perspective view, a side view, and a cross-sectional view of the joint. As shown in Fig. 5, joint 21 includes a cylindrical tubular portion 35, an anchor portion 37 disposed on the outside of tubular portion 35, and a holding portion 39 that holds tubular portion 35 relative to anchor portion 37.

[0060] The cylindrical portion 35 has an internal shape capable of fixing the collector wick 23 and the central core 29 therein. Specifically, the inner diameter of the cylindrical portion 35 is composed of a rear inner diameter portion 35a at the rear side that receives and fixes the relatively thick collector wick 23, and a front inner diameter portion 35b at the front side of the portion where the collector wick 23 is fixed that receives and fixes the relatively thin central core 29. Fixing methods include inserting the central core 29 and collector wick 23 into the cylindrical portion 35 and punching from the outside of the portion where the central core 29 and collector wick 23 are inserted, or making the outer diameter of the central core 29 larger than the inner diameter of the front inner diameter portion 35b and press-fitting, or other fixing methods. The press-fit method is preferred when a tight seal between the central core 29 and the front inner diameter portion 35b is required. Furthermore, when the central core 29 is weak and there is a concern that it may be crushed during assembly, fixing by punching is preferred, as this does not apply force to the central core 29.

[0061] The anchor portion 37 has a ring shape with an inner diameter larger than the outer diameter of the cylindrical portion 35, and is positioned rearward of the longitudinal center of the cylindrical portion 35. More specifically, the inner diameter of the anchor portion 37 is larger than the outer diameter of the cylindrical portion 35, and a space is formed between the anchor portion 37 and the cylindrical portion 35, and the tip holding portion 19 is inserted into this space. When the tip holding portion 19 is inserted into the space, the outer periphery of the tip holding portion 19 fits into the inner periphery of the anchor portion 37, and the anchor portion 37 is fixed to the tip holding portion 19. A cylindrical space is formed within the tip holding portion 19, and the inner diameter of this cylindrical space is larger than the outer diameter of the cylindrical portion 35, so that the cylindrical portion 35 and the tip holding portion 19 do not come into contact when the tip holding portion 19 and the cylindrical portion 35 are arranged coaxially.

[0062] The retaining portion 39 has a conical cylindrical shape that tapers forward from the outer periphery of the anchor portion 37 to the outer periphery of the tubular portion 35. By disposing the retaining portion 39 between the anchor portion 37, which is fixed to the tip holder 19, and the tubular portion 35, which is not fixed to any other member, and suspending the tubular portion 35 from the anchor portion 37, the tubular portion 35 and the core 29 and collector lead 23 of the writing part 13, which are fixed to the tubular portion 35, can be suspended axially movably from the outer 31, which is fixed to the front barrel 7. This makes it possible to absorb pressure applied to the core 29 during writing.

[0063] The cylindrical portion 35 and anchor portion 37 that make up the joint 21 are formed, for example, from a thermoplastic resin. The holding portion 39 is formed, for example, from a thermoplastic elastomer. Specific examples include styrene-based elastomers such as SBS, SEBS, and SEPS, olefin-based elastomers, urethane-based elastomers, and polyester-based elastomers. Among these, those with a durometer A hardness of 20 to 60 according to ISO 7619 provide a good balance between writing pressure and cushioning response. Furthermore, the cushioning properties of the joint 21 can be adjusted by adjusting the strength of the holding portion 39. Thermoplastic elastomers expand and contract sensitively to changes in load until just before the inflection point at which elastic deformation begins. Therefore, for example, by adjusting the thickness and composition of the holding portion 39 to set the inflection point of the load relative to the displacement to approximately 1 N, a joint 21 with excellent cushioning properties and highly expandable and highly sensitive to the load during writing can be formed. A certain degree of adhesion is required between the cylindrical portion 35 and the holding portion 39 to prevent them from peeling off during cushioning. To achieve this adhesion, it is preferable that the cylindrical portion 35 and the holding portion 39 are made of the same type of resin material, and selectable material combinations include a combination of AS (styrene-based resin) and SEBS (styrene-based elastomer), a combination of polypropylene (polyolefin-based resin) and EPDM (polyolefin-based elastomer), and a combination of PBT (polyester-based resin) and polyester-based elastomer.

[0064] Among these, the holding portion 39 preferably has a durometer A hardness according to ISO 7619 of 20 to 60 degrees, and most preferably 30 to 50 degrees. By setting the durometer A hardness of the holding portion 39 within this range, it can function properly even with low writing pressure and absorb pressure applied to the core 29.

[0065] By using the joint 21, it is preferable to set the cushioning force of the entire felt-tip pen to a range of 0.1 to 10 N, preferably 0.1 to 7 N, and more preferably 0.1 to 5 N. This is because if the cushioning force is too low, the outer 31 will always be in contact with the writing surface, such as the paper, during writing, making it difficult to draw thin lines. On the other hand, if the cushioning force is too high, it will be impossible to keep the outer 31 in contact with the paper during writing.

[0066] FIG. 6 is a drawing showing the outer 31, specifically, showing a perspective view, a side view, and a cross-sectional view of the outer 31. The outer 31 is a conical cylindrical body made of synthetic resin and formed into a generally conical shape, tapering toward the front. The outer 31 is preferably formed of a synthetic resin such as polyacetal or polybutylene terephthalate, which has a certain strength so as not to impair the writing feel and the feeling of pressing. The outer 31 can be made of a common synthetic resin. Specific examples include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, polyurethane, fluorine-based resin, ABS resin, AS resin, PMMA resin, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, and polyether ether ketone. Among these, polyacetal and polybutylene terephthalate are preferred because they do not impair the writing feel, especially when writing with strong friction, and are highly durable with little wear due to writing. By providing a certain strength to the outer 31, the durability of the outer 31 can be improved. Furthermore, the surface of the outer 31 is preferably smooth, which reduces frictional resistance between the outer 31 and the paper surface during writing and improves the writing feel. The Heidon value of the friction coefficient between the paper surface and the outer 31 during writing is preferably 0.5 or less, more preferably 0.25 or less. The Heidon value is measured using a surface roughness measuring instrument (HEIDON-14D, manufactured by Shinto Scientific Co., Ltd.). The measurement conditions are based on the old JIS (Japanese Industrial Standard) P3201 (high-quality paper made from 100% chemical pulp, basis weight range 40 to 157 g / m). 2 The outer 31 is moved linearly for 10 cm in the acute angle direction against writing paper (whiteness of 75.0% or more) under the conditions of a load of 100 g, a writing angle of 60 degrees, and a writing speed of 6.25 cm / sec.

[0067] The outer 31 also has a rear insertion hole 41 formed on the rear side and a front insertion hole 43 that communicates with the rear insertion hole 41 toward the front end and has a smaller diameter than the rear insertion hole 41. The front end of the joint 21 is inserted into the rear insertion hole 41, and a holder 27 fixed to the front end of the joint 21 protrudes from the front insertion hole 43. During assembly, the outer 31 is fixed to the front end of the front-side barrel 7 with the core 29 inserted into the front insertion hole 43 and the front end of the joint 21 inserted into the rear insertion hole 41. As a result, the core 29 in the outer 31 is held by the joint 21 so that it can move axially within the outer 31. The thickness of the tip of the outer 31, particularly near the front insertion hole 43, is preferably 0.02 to 0.2 mm. By setting the thickness of the tip of the outer 31 within this range, durability can be maintained while ensuring ink discharge during writing.

[0068] In addition, the outer 31 has a ring-shaped step 45 in its axial center portion, and the portion rearward of the step 45 has an outer diameter smaller than the inner diameter of the cylindrical space at the tip of the front barrel 7, so that the rearward side of the outer 31 can be fitted into the front barrel 7.

[0069] The main functions and effects of this embodiment are summarized below.

[0070] In this embodiment, the width of the drawn line can be adjusted according to the writing weight. More specifically, when the writing weight is reduced, the ink in the ink storage section 11 reaches the core 29 of the writing part 13 through the collector 17 and collector core 23 of the ink supply section 15. At this time, the core 29 does not recede, so the outer 31 does not touch the paper surface, and only the core 29 comes into contact with the paper surface, allowing a relatively thin line to be drawn. On the other hand, when the writing weight is increased, the core 29 recede, so that both the core 29 and the outer 31 come into contact with the paper surface, causing capillary force to act in the gap between the core 29 and the outer 31, allowing a relatively thick line to be drawn.

[0071] Furthermore, in this embodiment, the ink outlet portion at the tip is less likely to collapse, so the rate of change in line width between the beginning and end of use is small. More specifically, when a certain amount of load is applied to the core 29, which is the ink outlet portion at the tip, the core 29 retracts, and the outer 31 receives the writing pressure, making the core 29 less likely to collapse. Furthermore, because the outer 31 makes it possible to write thick lines, a relatively strong, thin core can be used for the core 29. Due to these effects, even with repeated writing, the rate of change in line width between the beginning and end of use can be kept to 20% or less, more preferably 10% or less.

[0072] Furthermore, the force applied to the core 29 from the paper surface during writing can be received by the outer 31. More specifically, when writing with strong writing pressure that increases the amount of wear on the writing part, the core 29 retracts, making it possible to reduce the writing pressure, and further, as the core 29 retracts and the outer 31 also comes into contact with the paper surface, the outer 31 can receive the writing pressure. This reduces wear on the writing part 13.

[0073] Furthermore, even if an excessive load is applied to the writing part 13, the load can be received by the outer casing 31. More specifically, even if an excessive load is applied to the writing part 13, such as if the writing part 13 is accidentally bumped, the outer casing 31 protects the outer periphery of the ink outlet part of the core 29, so the load is not applied to the core 29. This makes it possible to suppress deformation of the writing part 13.

[0074] Furthermore, in this embodiment, by adopting a joint 21 with high cushioning properties, a sufficient amount of ink can be discharged even with a light writing weight. This makes it possible to prevent "discontinuity of ink when writing" due to a lack of ink, even when used by a user with a light writing weight. This action and effect is particularly noticeable when pushing the pen, which is prone to "discontinuity of ink when writing."

[0075] In addition, in this embodiment, by appropriately selecting the ink components and adjusting the surface tension and fluidity of the ink, it is possible to more accurately control the amount of ink that flows out, and further, it is possible to suitably prevent the ink from staining the outer casing 31 of the writing part 13. Furthermore, by adjusting the ink components, it is possible to improve the writing performance of the felt-tip pen.

[0076] FIG. 7 is a cross-sectional view showing a modified core. As shown in FIG. 7, the modified core 129 has a resin core rod 131 that extends coaxially with the axis of the fibrous core 129. The core rod 131 has a circular cross section and extends through the core 129 from the ink storage section to the front end of the core 129. Ink in the ink storage section flows through the core 129 from the ink storage section to the front end of the core 129. The core 129 may be a porous material such as a heat-fused core or a sintered core. The core rod 131 may also be a fiber core that is harder than the core 129 or an extruded core with a flow path formed therein. The cross-sectional shape of the core rod 131 may also be an irregular shape such as a star shape. Furthermore, the core 129 may not have a core rod and may instead be a porous material such as a regular fiber core, a heat-fused core, or a sintered core.

[0077] Figure 8 is a cross-sectional view showing another modified example of the core. As shown in Figure 8, the core 133 according to this modified example has multiple passages 135 formed on its outer periphery. The multiple passages 135 extend from the rear end to the front end of the core 133 around the outer periphery of the core 133. The multiple passages 135 are also arranged at equal intervals in the circumferential direction. Ink in the ink storage section flows from the ink storage section to the front end of the core 133 through the multiple passages 135.

[0078] Figure 9 is a perspective view showing a modified outer pen. As shown in Figure 9, a plurality of grooves 139 are formed in the outer surface of the cone-shaped front side of the outer pen 137. The grooves 139 extend along the longitudinal direction of the outer pen 137 and are arranged at equal intervals in the circumferential direction. The capillary force of the plurality of grooves 139 allows ink to permeate into the grooves 139, making it possible to draw wider lines.

[0079] FIG. 10 is a cross-sectional view showing another modified example of the outer. As shown in FIG. 10, the outer 141 has multiple grooves 143 formed in the front insertion hole on the front side. The multiple grooves 143 extend longitudinally along the inner surface of the front insertion hole of the outer 141 and are arranged at equal intervals in the circumferential direction. Due to the capillary force of the multiple grooves 143, ink permeates into the grooves 143, and liquid is always retained in the writing portion, making it less likely that the ink will run out during writing. The outer 141 may have both the groove 139 shown in FIG. 9 and the groove 143 shown in FIG. 10.

[0080] 11 is a side cross-sectional view showing a modified example of the cap. As shown in FIG. 11, an ink retaining portion 147 is provided inside an inner cap 145. The ink retaining portion 147 is composed of a plurality of grooves 149 formed in a position facing the pen tip inside the inner cap 145 and extending radially from the shaft of the pen. By forming a plurality of grooves 149 in a position facing the pen tip, even if ink leaks from the pen tip due to being dropped or the like while the cap is closed, the grooves 149 can retain the ink.

[0081] 12 is a side cross-sectional view showing a modified example of the ink retaining portion. As shown in FIG. 12, an ink absorbing portion 153 made of a porous material such as a fiber wick, sponge, heat-sealed wick, or sintered material is formed inside an inner cap 151. The ink absorbing portion 151 is fixed inside the inner cap 149 so that it is positioned opposite the pen tip when the cap is closed. Providing such an ink absorbing portion 151 made of a porous material can also prevent ink leakage.

[0082] Examples based on the embodiments of the present invention will be described in detail below.

[0083] Example 1 A writing instrument having the following configuration was created. [Center core] Outer diameter: φ1.2mm, Material: Polyacetal [Collector core] Outer diameter: φ1.4 mm, Material: Polyethylene terephthalate [Outer] Material: Polyacetal [Ink] Water-based pigment ink (pigment concentration 11.5%) Viscosity: 2.6 mPa·s (ELD viscometer manufactured by Tokimec Co., Ltd., at a rotation speed of 50 rpm and a temperature of 25°C) Surface tension: 42.5 mN / m (surface tension measuring device CBVP-Z: Kyowa Interface Science Co., Ltd.) Average particle size 90nm (N4 PLUS: Beckman Coulter) [Others] Core projection: 0.3 mm, cushioning force: 1 N Using the above writing implement, 1-m lines were drawn alternately under writing conditions of a writing speed of 4.2 m / min, a writing angle of 65 degrees, and a writing weight of 50 g (first writing condition) and a writing speed of 4.2 m / min, a writing angle of 65 degrees, and a writing weight of 200 g (second writing condition), for a total of 9 m of lines. The rate of change in width of the drawn lines was then calculated. The rate of change in width was calculated by dividing the line width under the second writing condition by the line width under the first writing condition. The rate of change in width of the lines drawn using the writing implement according to the example was 4 to 5.8%.

[0084] (Comparative Example 1) As Comparative Example 1, a line was drawn under the same conditions using a felt-tip pen MYT-7 manufactured by Mitsubishi Pencil Co., Ltd. In this case, the rate of change in width was 34.4 to 56.4%.

[0085] Example 2 Using the writing implement used in Example 1, lines were drawn under writing conditions of a writing weight of 50 g and a writing angle of 80 degrees (third writing condition) and a writing weight of 200 g and a writing angle of 65 degrees (fourth writing condition), and the width ratio of the two was calculated. The width ratio of the line under the fourth writing condition divided by the width of the line under the third writing condition. The width ratio of the line drawn using the writing implement according to this example was 2.19.

[0086] (Comparative Example 2) As Comparative Example 2, a line was drawn under the same conditions using a felt-tip pen Pin05-200(S) manufactured by Mitsubishi Pencil Co., Ltd. The width ratio was 1.34.

[0087] Example 3 The writing implement used in Example 1 was prepared and fixed with the nib facing upward using a MAX series automatic load tester manufactured by Japan Measurement Systems Co., Ltd. A load of 5 N was then applied to the fixed writing implement at 1 mm / sec. The amount of crushing of the core of the nib was then measured using a NIKON MM-400 measuring microscope. The amount of crushing was measured from the amount of change in the core before and after the load. As a result, the amount of crushing of the nib in this example was 0.01 mm.

[0088] (Comparative Example 3) In Comparative Example 3, a load was applied under the same conditions using a MYT-7 felt tip pen manufactured by Mitsubishi Pencil Co., Ltd. The amount of crushing was 0.15 mm.

[0089] Example 4 The writing implement used in Example 1 was prepared and fixed with the pen tip facing upward using a MAX series automatic load tester manufactured by Japan Measurement Systems Co., Ltd. At this time, the angle of the pen with respect to the pressing surface was 60 degrees. A load of 20 N was applied at a speed of 1 mm / sec. The amount of breakage of the pen tip was then measured using a NIKON MM-400 measuring microscope. The amount of breakage was obtained by measuring the distance from the tip of the pen tip to the central axis after the load was applied. As a result, the amount of breakage of the pen tip in this example was 0.02 mm.

[0090] Comparative Example 4 In Comparative Example 4, a load was applied under the same conditions using a felt-tip pen Pin05-200(S) manufactured by Mitsubishi Pencil Co., Ltd. The amount of breakage was 0.56 mm.

[0091] Example 5 The writing implement used in Example 1 was prepared and subjected to a writing test in accordance with JIS 6037 under the conditions of a writing weight of 50 g, a writing speed of 4.2 m / min, and a writing angle of 65 degrees. As a result, the amount of wear of the pen tip was 0.05 mm.

[0092] (Comparative Example 5) As Comparative Example 5, a load was applied under the same conditions using a MYT-7 felt-tip pen manufactured by Mitsubishi Pencil Co., Ltd. At this time, the amount of wear of the pen tip was 0.34 mm.

[0093] Example 6 The writing implement used in Example 1 was prepared, and a line was drawn under the following conditions: writing angle 65 degrees, writing weight 50 g, and writing speed 4.2 m / min. The writing flow rate per unit area was calculated from the width of the line after writing. As a result, the writing flow rate was 5.99 to 6.55 g / m 2 It was.

[0094] (Comparative Example 6) In Comparative Example 6, a line was drawn under the same conditions using a Mitsubishi Pencil Co., Ltd. MYT-7 sign pen. The writing flow rate was 3.46 to 4.26 g / m 2 It was. [Explanation of symbols]

[0095] 1 felt-tip pen 11 Ink storage section 17 Collector 29 Core

Claims

1. an ink storage section that stores ink; an air replacement mechanism that sends ink out of the ink containing section by sending air into the ink containing section; a core for sucking the ink delivered by the air replacement mechanism by capillary force, delivering the sucked ink from the tip, and depositing the ink on a paper surface, A writing implement in which the rate of change in line width before and after writing is 10% or less when writing repeatedly with a writing weight of 50g and a writing weight of 200g.

2. 2. The writing implement according to claim 1, wherein the ratio of the width of a line that can be drawn under writing conditions of a writing angle of 60 degrees and a writing weight of 200 g to the width of a line that can be drawn under writing conditions of a writing angle of 90 degrees and a writing weight of 50 g is 1.5 or more.

3. 2. The writing implement according to claim 1, wherein the elastic limit point of the writing part including the core is 7.0 N or more.

4. 2. The writing implement according to claim 1, wherein the buckling strength of the writing portion including the core is 7.0 N or more.

5. 2. The writing implement according to claim 1, wherein the amount of wear of the center core when a 100 m line is drawn is 0.3 mm or less.

6. Writing flow rate per unit area is 5g / m 2 2. The writing implement according to claim 1 .

7. 2. The writing implement according to claim 1, wherein a cushioning force applied to the writing part including the core when the writing part begins to recede relatively to the barrel due to pressure is 0.1 N or more and 7 N or less.

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