Pen tip and writing implement equipped with said pen tip

Abstract

To provide a pen tip capable of enhancing color development at the pen tip and enhancing color discrimination at the pen tip, and a writing implement equipped with the pen tip. The pen tip A of the present invention is a pen tip provided with a pen tip 20 containing a concealing material, and the pen tip is L * a * b * (CIE LAB) color system lightness (L * The writing implement is characterized in that the value of the writing angle (the value of the writing angle) is 80 or more. This writing implement is characterized in that it comprises, for example, a holder 10 having a visible portion that allows the writing direction to be visually confirmed, and a pen tip A having the above-described configuration attached to the holder 10.

Description

Technical Field

[0001] The present invention relates to a pen tip that can enhance color development at the pen tip and improve color discrimination at the pen tip, and a writing instrument provided with this pen tip.

Background Art

[0002] Conventionally, the pen tip of a writing instrument called a paint marker, an underliner marker, etc. has a wide pen core to enable wide line drawing, and is widely used because it is excellent in the visibility and workability of marking. The pen tip of a writing instrument such as a line marker generally imparts capillary action to a porous member such as a rod-shaped aggregation of synthetic resin fibers or a sintered body of a polymer, and thereby ink supplied from the shaft body that becomes the writing instrument body is led out to the pen tip to enable writing.

[0003] In addition, with the spread of writing instruments that contain fluorescent ink in the shaft body that becomes the writing instrument body, writing instruments using pen tips with many structures and shapes that enable wide line drawing have been commercially available, enabling a wide selection of writing instruments according to the user's use, and the workability has also become comfortable.

[0004] Inks used in these line markers and the like include dye inks (aqueous dye inks, oil-based dye inks) using fluorescent dyes, oil-based dyes, etc. as colorants, and inks (pseudo pigments) in which dyes are encapsulated in resin fine particles. Since these inks are transparent in the colorant, the hue of the ink bulk itself and the appearance when impregnated in the pen core and the filler become dark. Note that pigment inks have good color development of the ink bulk itself.

[0005] When an ink with weak coloring power such as fluorescent ink (for example, yellow fluorescent ink) is impregnated in the pen refill, the hue of its appearance has no significant difference from the hue of the written line. However, when an ink with strong coloring power (inks such as pink, red, blue, and green) penetrates into the pen refill, even if the drawn line is a light color, the pen refill itself becomes blackish, making it difficult to distinguish the hue of the written line from the pen tip. In particular, in a writing instrument (for example, see Patent Document 1) provided with a visible part (window part) at the pen tip that allows the writing direction to be visually recognized, since the pen tip is large and the cap is transparent, there are problems such as the blackness of the pen tip being prominent and the vividness and color discrimination being reduced.

[0006] On the other hand, as a prior art in which the pen tip is subjected to processing such as resin coating and coloring, for example, 1) For the purpose of preventing the ink from bleeding and spreading to the tip of the pen shaft and causing contamination, and preventing the fluffing of the surface of the raw rod made of fiber, and making the pen tip less likely to fall apart, in a raw rod for a fiber pen tip body formed by converging fibers in the longitudinal direction by heat processing and a resin binder, the surface is coated and covered with a vehicle having a cellulose derivative containing a colorant as a coating component. A raw rod for a fiber pen tip body (for example, see Patent Document 2), 2) A pen tip obtained by processing a fiber bundle formed by binding synthetic fibers with a binder into the shape of a pen tip and then coloring it by dyeing, so that the entire surface of the pen tip is colored, and a uniformly colored pen tip without unevenness can be obtained regardless of whether it is a light color or a dark color, and the color can be easily changed only by changing the dye. (For example, see Patent Document 3) and the like are known.

[0007] However, the fiber-based pen tip rods and pen tips described in Patent Documents 2 and 3 above have part or all of the pen tip surface pre-colored. However, when ink with strong coloring power soaks into the pen tip, the pen tip may still appear dark in color. Furthermore, coloring by dyeing can limit the types of ink that can be used. In addition, there are problems such as a subtle difference between the hue of the colored pen tip and the hue of the written line. Patent Documents 2 and 3 and the present invention differ in their objectives, problems, and technical concepts (structure and its effects). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2000-52682 (Claims, Figure 7, etc.) [Patent Document 2] Japanese Patent Publication No. 8-267982 (Claims, Figure 3, etc.) [Patent Document 3] Japanese Patent Publication No. 2003-11569 (Claims) [Overview of the project] [Problems that the invention aims to solve]

[0009] In view of the problems and current state of the prior art described above, the present invention aims to resolve these issues and to provide a pen tip that can enhance color development at the pen tip, improve color discrimination at the pen tip, and eliminate the difference in hue between the colored pen tip and the written line, as well as a writing instrument equipped with such a pen tip. [Means for solving the problem]

[0010] As a result of diligent research to solve the above-mentioned conventional problems, the inventors have found that a pen tip with a pen core, wherein the pen core contains an opaque material and its brightness is set to a specific value or higher, can be obtained to achieve the above-mentioned objectives and a writing instrument equipped with this pen tip, thus completing the present invention.

[0011] In other words, the pen tip of the present invention is a pen tip equipped with a pen core containing an opaque material, and the pen core in an ink-free state is L* a * b * (CIE LAB) Lightness (L) * It is characterized by having a value of 80 or higher. Furthermore, the brightness (L) when the pen tip is filled with ink. * The value is characterized by being 30 or greater. The aforementioned concealing material is preferably at least one selected from titanium dioxide, zinc oxide, boron nitride, and barium sulfate, with an average particle size of 50 to 1000 nm. Furthermore, it is preferable that the pen tip is composed of a sintered core or a fiber bundle core, and that the concealing material is fixed to the sintered core or fiber bundle core. The writing instrument of the present invention is a writing instrument having a pen tip with the above configuration, characterized in that the writing instrument is equipped with dye ink or resin fine particle pigment ink containing dye. It is preferable that the color difference △E between the writing line and the pen tip is less than 40. [Effects of the Invention]

[0012] According to the present invention, a pen tip is provided that can enhance the color development at the pen tip and improve color discrimination at the pen tip, and that there is no difference in hue between the colored color of the pen tip and the hue of the written line, as well as a writing instrument equipped with this pen tip. [Brief explanation of the drawing]

[0013] [Figure 1] This shows an example of an embodiment in which the pen tip of the present invention is attached to the front barrel of a writing instrument. (a) is a perspective view taken from the left, and (b) is a perspective view taken from the right, which is the opposite of (a). [Figure 2] These drawings illustrate an example of an embodiment of the pen tip of the present invention, where (a) is a rear view, (b) is a top view, (c) is a front view, (d) is a longitudinal section view, (e) is a perspective view from the left, (f) is a perspective view of (e) from the right, (g) is a right side view, (h) is a left side view, (i) is a perspective view from the left, the opposite of (e), and (j) is a perspective view of (i) from the right. [Figure 3] (a) to (j) are drawings showing examples of a holder, where (a) is a rear view, (b) is a top view, (c) is a front view, (d) is a longitudinal section view, (e) is a perspective view from the left, (f) is a perspective view of (e) from the right, (g) is a right side view, (h) is a left side view, (i) is a perspective view from the left, the opposite of (e), and (j) is a perspective view of (i) from the right. [Figure 4] Figure 2 is a partial longitudinal cross-sectional view showing an example of a writing instrument using a pen tip. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described in detail below with reference to the drawings. Figures 1(a) and 1(b) are perspective views showing an example of an embodiment in which the pen tip of the present invention is attached to the front barrel of a writing instrument; Figures 2(a) to 2(j) are drawings showing an example of an embodiment of the pen tip of the present invention; Figures 3(a) to 3(j) are drawings showing an example of a holder; and Figure 4 is a partial longitudinal cross-sectional view showing an example of a writing instrument using the pen tip of Figure 2. As shown in Figures 1 and 2, the pen tip A of this embodiment comprises a holder 10 having a visible portion that allows the writing direction to be visually confirmed, and a pen tip 20 attached to the holder 10.

[0015] As shown in Figures 1, 2(a) to (j), and 3(a) to (j), the holder 10 fixes the pen tip 20, which is the writing lead, to the tip opening of the shaft 35 of the barrel 30. It has a bulging main body portion 11, a flange portion 12 on the front side of the main body portion 11, and a visible portion 13 that allows the writing direction to be seen. The visible portion 13 has front holding portions 14a and 14b that hold the tip side (end face) of the pen tip 20. In this embodiment, the longitudinal lengths of the front holding portions 14a and 14b are different; that is, the front holding portion 14a is longer and the front holding portion 14b is shorter, with the tip end of the front holding portion 14a being at the same position (end) as the tip end of the pen tip 20, and the front holding portion 14b being shorter by the amount of protrusion (protrusion length) as will be described later. In the above-described holder 10, there is a long front holding portion 14a and a short front holding portion 14b that hold the tip side (end face) of the pen tip 20, but the holding lengths of the front holding portion 14a and the front holding portion 14b may be the same. Furthermore, the main body portion 11 is provided with a rear retaining portion 16 having a retaining piece 15 connected to the main body portion 11 on its rear side. A retaining groove 17 is formed on the entire longitudinal outer surface of the retaining body 10 composed of these members, for fitting and holding the U-shaped pen tip 20, which will be described later. In addition, a concave fitting portion 11a is formed on the widthwise outer surface of the main body portion 11, and a straight air circulation groove 11b and a curved air circulation groove 11c are formed on the double-sided air circulation grooves that make up the longitudinal outer surface.

[0016] The entire holding body 10 configured as described above is made of a hard material, for example, a hard material with visibility, such as metal, glass, resin without rubber elasticity, etc. As the resin without rubber elasticity that can be made visible, for example, materials with a visible light transmittance of 50% or more such as PP, PE, PET, PEN, nylon (including amorphous nylon etc. in addition to general nylons such as nylon 6 and nylon 12), acrylic, polymethylpentene, polystyrene, ABS, etc. are formed by molding, so that the characters written in the writing direction in the visible part 13 can be effectively visually recognized. Note that only the visible part 13 may be made of a material with visibility. Note that the visible light transmittance can be obtained by measuring the reflectance with a multi-source spectrocolorimeter [manufactured by Suga Test Instruments Co., Ltd., (MSC-5N)]. Also, the holding body 10 may be composed of one type of the above materials, or two or more types of materials in view of further improving durability and visibility, and can be molded by various molding methods such as injection molding and blow molding.

[0017] As shown in FIGS. 1 and 2(a) to (j), this pen core 20 has a circular cross-section and is generally U-shaped as a whole, and includes ink guiding parts 21, 21 and a writing part 22 for guiding the ink from the ink guiding parts 21, 21. The corners between the ink guiding parts 21, 21 and the writing part 22 have cut surfaces 23, 23 where the corners are cut off. Also, a cut smooth surface part 21a that is a smooth surface is formed on the surface parts of the ink guiding parts 21, 21.

[0018] In the present invention, the pen core 20 having the above structure contains a concealing material and has an L value of 80 or more in the (CIE LAB) color system in a state where it does not contain ink. * a * b * (lightness (L value) * in the (CIE LAB) color system) The above L * a * b *The CIE LAB color system is one method of representing color tones for hue evaluation, and was developed by the International Commission on Illumination (CIE) to represent visible colors as a color space. This lightness (L * The value is an indicator showing the brightness trend, and is in the range of 0 to 100. * By setting the value to 80 or higher, the color development at the pen tip can be enhanced, improving color discrimination at the pen tip. On the other hand, brightness (L * If the value is less than 80, the effects of the present invention cannot be achieved. Preferably, in order to further exhibit the effects of the present invention, the brightness (L) * The value should preferably be in the range of 90 to 100. Also, the achromaticity C * It is more preferable that the value be less than 30. Note: Achromaticity C * This is calculated using the following formula (B). Achromaticity C * =( a *2 +b *2 ) 1 / 2 ...(B)

[0019] In the present invention, L in the pen tip 20 containing the concealing material * a * b * (CIE LAB) Lightness (L) * Methods to increase the value to 80 or more include including an opaque material, thereby increasing the brightness (L) * As long as the value can be 80 or higher, there are no particular limitations. For example, methods include fixing a concealing material to the pen nib after molding, or constructing the pen nib by combining the materials that make up the pen nib with the concealing material. Specific manufacturing methods will be described later. The opacifying material that can be used is at least one selected from titanium oxide, zinc oxide, boron nitride, and barium sulfate (either alone or as a mixture of two or more, the same applies hereinafter), which are high refractive index materials, and its average particle size is preferably 50 to 1000 nm. By setting the average particle size of this opacifying material to 50 nm or more, the opacifying material can be efficiently incorporated into the pen nib, while keeping it below 1000 nm does not impair ink flow. More preferably, the average particle size is 100 to 500 nm.

[0020] The amount of this opacifying material is such that by including the opacifying material in the pen nib, it imparts weak opacity to the pen nib, resulting in the above brightness (L * While there are no particular limitations, as long as the value can be made to 80 or higher, further enhancing the color development at the pen tip and further improving color discrimination at the pen tip, it is preferable that the amount is 0.01 to 10% by mass, and more preferably 1 to 5% by mass, relative to the total amount of the pen tip, in order to facilitate ink flow in the pen nib and the adhesion and compounding of the concealing material to the pen nib.

[0021] On the other hand, the pen nib 20 contains the above-mentioned concealing material, but as a basic performance, it has good ink flowability and is therefore composed of a porous material. For example, this pen nib is made of a parallel fiber bundle made of one or more types of natural fibers, animal hair fibers, polyacetal resin, polyethylene resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, polyolefin resin, polyvinyl resin, polycarbonate resin, polyether resin, polyphenylene resin, etc., processed fiber bundles such as felt, or a fiber core made by resin processing these fiber bundles, or a porous body (sintered core) made by sintering plastic powder such as thermoplastic resin such as polyolefin resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, etc. Preferred pen cores 20 include fiber bundle cores, fiber cores, sintered cores, felt cores, sponge cores, and inorganic porous cores, with sintered cores being particularly preferred from the viewpoint of deformability and productivity.

[0022] In the present invention, specific methods for manufacturing the pen nib 20 having the above characteristics include, for example, 1) a manufacturing method in which the molded pen nib is impregnated in a processing liquid containing at least an opacity material and a fixing resin, and then dried and fixed; 2) a method for manufacturing the pen nib by compounding the material constituting the pen nib with the opacity material; and 3) a method for manufacturing the pen nib after mixing or embedding the opacity material within the material constituting the pen nib.

[0023] As the fixing resin used in 1) above, acrylic resin, styrene acrylic resin, urethane resin, etc. can be used, considering factors such as ink flowability and not affecting the ink. In this manufacturing method, in order to ensure good ink flowability (porosity described later) without clogging the pen nib, a processing solution is prepared containing a fixing resin with a solid content of 1 to 30% by mass, an opacifying material, and a solvent as needed. A pen nib composed of a molded fiber bundle core, fiber core, sintered core, felt core, sponge core, inorganic porous core, etc. is impregnated into the processing solution, dried, and fixed, thereby producing a pen nib with the above-mentioned predetermined porosity and predetermined proportion of opacifying material fixed to it. Alternatively, the porosity of the pen nib can be increased (made larger) beforehand, and then impregnated with the above-mentioned treatment liquid to reduce the porosity, resulting in a pen nib with a predetermined porosity and a predetermined proportion of opaque material fixed to it.

[0024] The method for manufacturing a pen core by compounding the pen core material and concealing material as described in 2) above is, for example, if the pen core is a sintered core, by mixing at least the above-mentioned plastic powder and concealing material in a predetermined ratio and then sintering under suitable conditions, a pen core can be obtained in which a predetermined porosity and a predetermined ratio of concealing material are compounded. As for the manufacturing method of item 3) above, one method is to mix the above-mentioned concealing material (including fibrous titanium oxide, etc.) into a molten resin which will be the fibrous material constituting the pen core, spin the fibers containing the concealing material to form fibers, and then use these fibers to make the above-mentioned fiber bundle core or fiber core. In addition, if the pen core is a sintered core, at least the above-mentioned concealing material can be pre-encapsulated in the plastic powder, a substrate for the sintered core can be prepared, and then sintered under suitable conditions to obtain a pen core having a predetermined porosity and a predetermined proportion of concealing material.

[0025] Furthermore, the pen nib 20 used in the present invention contains the above-mentioned opacity material in a predetermined proportion, and its porosity, size, hardness, etc., vary depending on the manufacturing method by which the opacity material is fixed or compounded, the type of ink, the type of writing instrument, etc. For example, the porosity is preferably 30 to 60%. The pen tip 20 of this embodiment is composed of a sintered core (sintered body) with a porosity of 55%, which is made by sintering polyethylene powder with an average particle diameter of 200 μm and titanium oxide with an average particle diameter of 350 nm. In this invention, "average particle diameter" refers to the average value of the diameter of particles measured with an electron microscope, and is the average value of the particle diameters measured for 20 particles in the image projected onto the electron microscope. If the particle is not circular, the particle diameter of that particle is the value obtained by adding the length of the longest line segment and the length of the shortest line segment connecting any two points on the contour that forms the pores, and dividing by 2. Furthermore, porosity is calculated as follows. First, a pen nib with a known mass and apparent volume is immersed in water and allowed to soak thoroughly. After removing it from the water, its mass is measured. From the measured mass, the volume of water soaked into the pen nib is derived. Assuming this water volume is the same as the pore volume of the pen nib, the porosity is calculated from the following formula (A). Porosity (unit: %) = (volume of water) / (apparent volume of pen nib) × 100 ……(A)

[0026] Furthermore, the length t in the width direction of the pen nib 20 in this embodiment is preferably 0.50 mm or more, and more preferably 1.00 to 3.00 mm, in order to ensure sufficient writing flow. The writing section 22 is angled (knife-cut shape) to facilitate writing, and this angle can be set as appropriate to suit the ease of use for writing. Furthermore, the writing section 22 has a thick line width W, preferably 1 mm or more, and more preferably 2 mm or more.

[0027] In this pen tip A, the pen tip 20 is fixed (attached) to the holder by inserting the pen tip 20 into the retaining groove 17 and fixing it in place by the front retaining parts 14a, 14b and the rear retaining part 16 having a retaining piece 15. Furthermore, in order to ensure that the pen tip 20 is fixed (prevents it from coming loose), adhesive bonding or welding may be used. In addition, a wedge-shaped non-smooth surface portion may be formed on the contact surface of the retaining groove 17 of the holder 10 that contacts the writing part 22 of the pen tip 20 to further ensure that the pen tip 20 is fixed to the holder 10. In this embodiment, as shown in Figure 2(d), the wedge-shaped non-smooth surface portion 18 is formed.

[0028] In this embodiment, as shown in Figure 2(b), the amount Y protruding from the tip of the pen nib 20 from the holder 10 is 0.65 mm or more and less than 1 mm. This structure ensures that even when writing with a strong writing load, the amount Y protruding from the tip of the pen nib 20 is kept as close to the inner surface of the holder as possible, thus preventing damage to the pen nib without impairing writing performance and resulting in excellent durability. If the protrusion amount Y is shorter than 0.65 mm, the holder may come into contact with the pen when writing with the pen body held at an angle, potentially preventing writing. On the other hand, if the protrusion amount Y is longer than 1 mm, strong writing loads may impair writing performance. In Figure 4(d), X represents the width of the pen nib, and it is preferable that the above-mentioned protrusion amount Y is 0.65 mm or more and less than 1 mm, and also less than 50% of the width X of the pen nib.

[0029] Furthermore, in addition to the above embodiments, the present invention also allows for preventing damage to the pen nib without impairing writing performance and providing superior durability by setting the amount of protrusion Y of the tip side of the pen nib 20 from the holder 10 to 40-65% of the thickness t of the pen nib. By setting the amount of protrusion Y of the tip side of the writing nib to 40-65% of the thickness t of the pen nib 20 (Y / t = 40-65%), even when writing with a strong writing load, the strength of the pen nib can be further maintained due to the relationship between the amount of protrusion Y of the tip side of the pen nib 20 and the thickness of the writing nib. In addition, the structure is such that the amount of protrusion Y is pressed against the pen nib as much as possible on the inner surface of the holder, thus further preventing damage to the pen nib without impairing writing performance and providing superior durability. More preferably, it is desirable that the amount of protrusion Y of the tip side of the pen nib 20 be 48-58% of the thickness t of the pen nib. If the protrusion amount Y is less than 40% of the pen tip thickness t, strong writing pressure may impair writing performance. On the other hand, if it exceeds 65%, the holder becomes thicker, making it difficult to see the paper while writing. Hereinafter, X is the pen tip width X, and it is preferable that the above protrusion amount Y is 40-65% of the pen tip thickness t, as well as less than 50% of the pen tip width X (Y / X is less than 50%). In particular, a preferred configuration is one in which the amount Y protruding from the tip side of the writing lead from the holder is 0.65 mm or more and less than 1 mm, and is 40-65% of the writing lead thickness t.

[0030] The pen tip A of the present invention, configured in this manner, comprises at least a holder 10 having a visible portion 13 that allows the writing direction to be seen, and a pen tip 20 having the above characteristics attached to the holder 10, wherein the pen tip 20 contains the above-mentioned concealing material by fixing, compounding, etc., and the pen tip is L * a * b * (CIE LAB) Lightness (L) * By setting the value to 80 or higher, the color development at the pen tip is enhanced, improving color discrimination at the pen tip.

[0031] The writing instrument of the present invention is characterized by having a pen tip having the above configuration. However, since the writing instrument of the present invention is characterized by having a pen tip having the above configuration, the configuration other than the pen tip is not particularly limited. Figure 4 shows an example of an embodiment of the writing instrument of the present invention, and is a partial longitudinal cross-sectional view showing an example of a writing instrument using the pen tip A of Figure 2. The writing instrument B of this embodiment comprises the pen tip A, the barrel 30 which forms the body of the writing instrument, the ink reservoir 40, and the caps 50 and 51 as described above.

[0032] As shown in Figure 4, this writing instrument B has an ink-absorbing body 40 inside a barrel 30 that serves as the writing instrument body, which stores ink. One end (right side of Figure 4) has a fine-tip pen body 31, and the other end (left side of Figure 4) has a pen tip A with the above configuration. The ink from the ink-absorbing body 40 is supplied to the pen tip 31 and the pen tip A's feed 20, respectively, by capillary action. Reference numerals 50 and 51 indicate transparent or pendant-shaped caps that protect the pen tip A and pen body 31 and are detachably fitted to both ends of the barrel 30, which will be described later.

[0033] The shaft 30 is made of, for example, a thermoplastic resin, a thermosetting resin, etc., and consists of a cylindrical body that houses an ink-absorbing body 40 impregnated with writing instrument ink. The right end of the shaft, shown in Figure 4, has a rear shaft holding part 33 with a fitting part for fixing the rear shaft 32 that holds the fine-tip pen body 31 by fitting, and the other end, shown in Figure 4, has a front shaft 35 to which the pen tip A of the above configuration is fixed. The barrel 30 is molded into a cylindrical shape using a resin such as polypropylene, and functions as the main body (barrel) of the writing instrument. The entire barrel 30 and the front barrel 35 are molded to be opaque or transparent (and semi-transparent), and either can be used from an appearance or practical standpoint. The front barrel 35 is fixed to the front side of the barrel 30 by fitting or the like. The ink-absorbing body 40 is impregnated with writing instrument ink such as water-based ink or oil-based ink, and includes, for example, fiber bundles made from one or more combinations of natural fibers, animal hair fibers, polyacetal resins, acrylic resins, polyester resins, polyamide resins, polyurethane resins, polyolefin resins, polyvinyl resins, polycarbonate resins, polyether resins, and polyphenylene resins, processed fiber bundles such as felt, and porous bodies such as sponges, resin particles, and sintered bodies. This ink-absorbing body 40 is housed and held within the shaft 30.

[0034] The composition of the ink used for writing instruments is not particularly limited, and a suitable formulation such as water-based dye ink, oil-based ink, or thermochromic ink can be used depending on the intended use of the writing instrument. For example, in underline pens, the ink can contain fluorescent dyes, such as Basic Violet 11, Basic Yellow 40, or thermochromic microcapsule pigments. Preferably, a dye ink or a resin fine particle pigment ink containing a dye is desired. Examples of dye-containing resin microparticle pigment inks include a dispersion of colored resin microparticles in which the colored resin microparticles are dispersed in water, wherein the colored resin microparticles are composed of at least (meth) cyclohexyl acrylate monomer and a basic dye or an oil-soluble dye, the content of the (meth) cyclohexyl acrylate monomer is 30% by mass or more relative to the total polymer components constituting the colored resin microparticles, and the content of the basic dye or oil-soluble dye is 15% by mass or more relative to the total polymer components, a water-soluble organic solvent, and water. Furthermore, it is preferable to set the ink viscosity (25°C: Complate viscometer) to 1 to 5 mPa·s, the surface tension to 30 to 60 mN / m, and the ink flow rate from the pen tip 20 and pen body 31 to 5 to 20 mg / m by adjusting the types of ink components and their respective proportions. In this invention, in order to further enhance the effects of the present invention, it is preferable that the color difference △E between the writing line and the pen tip is less than 40. A lower color difference △E is desirable, as a △E of 40 or more makes it difficult to effectively exhibit color discrimination. This color difference can be adjusted by suitably adjusting the type of colorant, ink, opacity material, and their content used. Furthermore, in order to further demonstrate the effects of the present invention, preferably the brightness (L) of the pen tip in an ink-impregnated state is * The value should preferably be 30 or higher. Furthermore, if the ink for the writing instrument is a thermochromic ink, a thermoplastic elastomer with an erasing ability (erasing rate) of less than 70% of pencil lines as specified in JIS S 6050-2002 can be formed on the top of the cap 50, making it possible to create a friction body that easily generates frictional heat through rubbing and has low wear.

[0035] When the pen tip A, which consists of at least the holder 10 to which the pen nib 20 with the above configuration is fixed, is inserted into the front barrel 35, the writing nib 20 is attached (fixed) to the barrel 30, which becomes the writing instrument body, via the holder 10, and the rear ends 21a, 21a of the ink guiding parts 21, 21 of the pen nib 20 are configured to fit into the tip side of the ink storage body 40. Furthermore, when the rear barrel 32, which holds the pen body 31, is inserted into the rear barrel holder 33 of the barrel 30, the pen body 31 is attached (fixed) to the barrel 30, which becomes the writing instrument body, by fitting or the like. Furthermore, a recess may be formed inside the tip side of the ink storage body 40 for inserting the rear ends 21a, 21a of the ink guide sections 21, 21. In addition, when the pressure inside the barrel 30 increases, ink dripping may occur from the pen tip, but in the writing instrument B of this embodiment, as shown in Figure 2, the air inside the barrel 10 and the outside air are regulated via the air circulation grooves 11b, 11c. The cap 50 is made of a transparent resin or the like that provides visibility and is detachably attached to the outer circumference of the tip side of the front shaft 15 by fitting or the like, while the cap 51 is detachably attached to the outer circumference of the end of the shaft body 30 in the opposite direction to the front shaft 35 by fitting or the like.

[0036] In the writing instrument B of the present invention, an ink-absorbing body 40 containing writing ink is inserted and held inside the shaft 30 of the writing instrument. The tip end is fixed to the pen tip A with the above configuration by sequential fitting or the like via the front shaft 35, and the other end is fixed to the rear shaft holding part 33 to which the pen body 31 is fixed by fitting. In this way, the writing instrument B can be easily manufactured, and the ink absorbed in the ink-absorbing body 40 is efficiently supplied by capillary action to the writing part 22 of the pen feed 20 of the pen tip A and to the pen body 31, for use in writing.

[0037] In the twin-type writing instrument B configured in this way, as shown in Figures 4 and 1, the pen tip A comprises a holder 10 having at least a visible portion 13 on one end that allows the writing direction to be seen, and a pen tip 20 attached to the holder 10. The pen tip 20 contains the aforementioned concealing material through fixation, compounding, etc., and the pen tip is L * a * b * (CIE LAB) Lightness (L) * Since the value is set to 80 or higher, it is possible to enhance the color development at the pen tip and improve color discrimination at the pen tip. Furthermore, by looking at the viewing side with the visible part 13, it becomes possible to obtain a writing instrument B having a pen tip that makes it easier to align the starting position of the stroke.

[0038] In the writing instrument B of this embodiment, conventionally, when ink with strong coloring power (such as pink, red, blue, or green ink) soaks into the pen tip, even if the drawn line is a light color, the pen tip itself becomes a dark color, making it difficult to distinguish the hue of the written line from the pen tip. However, with the pen tip A having the above characteristics, the color development at the pen tip is enhanced, there is almost no difference in hue between the written line and the pen tip, and the color discrimination at the pen tip can be improved. Furthermore, by looking at the visible side in the visible part 13, it becomes easier to align the starting position of the stroke. Also, the amount Y of the protrusion of the tip side of the pen nib 20 from the holder 10 is 0.65 mm or more on the longer side of the holder and less than 1 mm on the shorter side of the holder, and the lengths of the front holder parts 14a and 14b that hold the tip side of the pen nib 20 are different. Specifically, the front holder part 14a is longer and the front holder part 14b is shorter, so in particular when writing from left to right as a right-handed person, the protrusion (amount of protrusion) is used to draw the line. Moreover, the longer front holding portion 14a on the left side securely holds (protects) the protruding portion of the pen tip, thereby increasing its strength. As a result of the holding structure of the writing section 22, which consists of a longer front holding portion 14a and a shorter front holding portion 14b that hold the tip side (end face) of the pen tip 20, and the limitation of the amount of protrusion Y, even when writing with a strong writing load, the writing performance of the tip side of the pen tip 20 is not impaired, and the structure is designed to hold the writing tip as much as possible on the inner surface of the holder 10 (14a), thus preventing damage to the pen tip 20 and providing a writing instrument with excellent durability. Furthermore, in this embodiment, the holder 10 is designed so that the end face of the holder 10 on the opposite side of the writing direction protrudes from the end face of the holder on the writing direction side, providing a writing instrument that is particularly effective when writing from left to right with the right hand. Furthermore, when the end face of the holder 10 is formed to protrude to the opposite side, a writing instrument is provided that is particularly effective when writing with the left hand from right to left or with the right hand from top to bottom.

[0039] Furthermore, in the writing instrument B described above, by setting the amount Y of the tip of the writing lead 20 protruding from the holder 10 to 40-65% of the thickness t of the writing lead, damage to the pen lead 20 is prevented, as in the above embodiment, resulting in a writing instrument with superior durability. In other words, in this embodiment as well, by setting the amount Y of the tip of the pen lead protruding to 40-65% of the thickness t of the pen lead, even when writing with a strong writing load, the strength of the pen lead can be further maintained due to the relationship between the amount Y of the tip of the pen lead protruding to the thickness of the pen lead, and the structure is such that the amount of protrusion Y is pressed against the inner surface of the holder as much as possible, thereby providing a writing instrument with superior durability that prevents damage to the pen lead without further impairing writing performance.

[0040] The pen tip and writing instrument of the present invention are not limited to the embodiments described above, and can be modified in various ways without altering the technical concept of the present invention. Furthermore, although the above embodiment described the pen tip 20 as a sintered core type, the pen tip 20 may also be made of materials other than a sintered body, such as a fiber bundle, fiber core, foam, sponge, or felt, as described above. Furthermore, although the above embodiment shows a writing instrument in which ink absorbed in the ink-absorbing body 40 is efficiently supplied to the writing section 22 of the pen nib 20 by capillary force (cotton-filled type), a writing instrument equipped with a valve mechanism may also be used. For example, an ink chamber in which ink is directly contained within the shaft that forms the body of the writing instrument is provided, a valve mechanism is provided between the ink chamber and the writing nib, and by pressing in the direction of the pen tip, the valve rod is retracted against the biasing force of the spring of the valve mechanism to release the valve and release the ink, thereby supplying ink to the pen nib.

[0041] Furthermore, in the above embodiment, a twin-type writing instrument was described having a pen tip A with a pen nib 20 attached to a holder 10 having a visible portion 13, and a pen body 31 on the opposite side. However, the pen body 31 may be omitted (the barrel may be a bottomed cylindrical barrel), and the pen nib 20 may be a single-type writing instrument. Alternatively, it may be a retractable writing instrument. In the writing instrument B of the above embodiment, the cross-section of the shaft of the writing instrument body is formed as a circular shaft, but it may also be formed as an irregular shape such as a triangular shape, a square or more sides of a rectangle, or an elliptical shape. Furthermore, although the above embodiments described inks for writing instruments (water-based dye inks, oil-based inks, thermochromic inks, and resin fine particle pigment inks containing dyes) may be used, liquid substances such as liquid cosmetics, liquid pharmaceuticals, coating solutions, and correction fluids may also be used. [Examples]

[0042] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0043] [Example 1] The following components were used: a pen tip, writing instrument, processing solution, and writing ink, all conforming to the configuration and Figures 1-4. The dimensions of the pen nib, holder, etc., were as shown below.

[0044] (Configuration of the retainer 10) Made of acrylic resin, with a visible light transmittance of 85%. [Reflectance was measured using a multi-light source spectrophotometer (MSC-5N) manufactured by Suga Test Instruments Co., Ltd., and the visible light transmittance was determined from this.] Visible part 13 (square) after pen tip installation: 5mm x 6mm x 3mm x 4mm (Composition of 20 pen nibs) Polyethylene (PE) sintered core, 60% porosity (after concealing material fixation), writing section 22: W=4mm, knife-cut shape, ink guide section: φ(t)1.6mm, protrusion Y=0.85mm (53% of t), protrusion Y' on the opposite side of protrusion Y=0.65mm (40% of t), writing core width X=1.75mm

[0045] (Configuration of writing instrument components other than the holder 10 and pen tip 20) Ink absorbent material: PET fiber bundle, 85% porosity, φ6 × 77mm Writing instrument body and cap: Made of polypropylene (PP) Pen body 31: Polyester fiber bundle core, 60% porosity, φ2.0 × 40.0 mm

[0046] (Composition of the treatment solution for fixing the concealing material to the pen tip) The following treatment solution (total 100% by mass) was used for the pen nib 20. Titanium dioxide (average particle size 350 nm) 3.8% by mass Adhesive resin (styrene-acrylic resin, solid content concentration: 30%) 7.7% by mass Deionized water remaining

[0047] (Method for fixing the treatment solution to the pen nib) Using the above processing solution, the concealing material was fixed to the pen tip 20 by the following method. First, the pen nib was impregnated and then dried for 2 hours at 80°C under dry conditions to allow the opacifying material to be incorporated into the pen nib 20. The amount of opacifying material (titanium dioxide) fixed was approximately 4% by mass in the change in mass (excluding the amount of fixed resin) before and after impregnation.

[0048] (Pen tip 20 brightness (L) * Value), achromaticity C * (Measurement, etc.) Pen nib 20 L * a * b * (CIE LAB) Lightness (L) * The value (C) was measured using the following device, and the achromaticity C was measured. * The result was calculated. (Measuring equipment) Nippon Denshoku Industries Co., Ltd. VSS7700 Micro-surface Spectroscopic Colorimeter Pen tip 20 brightness (L * Value) = 90, achromaticity C * =10

[0049] (Writing instrument ink composition: Ink colors: Blue, Red) Dispersions of colored resin fine particles as shown in Production Examples 1 and 2 below were used. Note that "parts" below refers to parts by mass. The total amount of each component in Production Examples 1 and 2 is 500 parts. (Manufacturing Example 1) A 2-liter flask was fitted with a stirrer, reflux condenser, thermometer, nitrogen gas inlet tube, and 1000 ml separatory funnel for monomer input, and placed in a hot water bath. 329.5 parts distilled water, 5 parts glycerin monomethacrylate [Bremmer GLM, NOF Corporation], 5 parts sodium 2-sulfoethyl methacrylate [Acrylic Ester SEM-Na, Mitsubishi Chemical Corporation], 20 parts polymerizable surfactant [ADEKA Corporation, Adekarya Soap SE-10N, ether sulfate], and 0.5 parts ammonium persulfate were charged into the flask, and the internal temperature was raised to 50°C while introducing nitrogen gas. On the other hand, a solution was prepared by mixing a mixed monomer consisting of 55 parts of cyclohexyl methacrylate monomer and 35 parts of n-butyl methacrylate as another monomer, with 40 parts of an oil-soluble dye [Savinyl Blue GLS, manufactured by Clariant Inc.] and 10 parts of a crosslinking agent [Triallyl isocyanurate, manufactured by Nippon Chemical Corporation, "TAIC"]. This prepared solution was added from the separatory funnel into the flask, which was kept at a temperature of approximately 50°C, under stirring for 3 hours to carry out emulsion polymerization. After further aging for 5 hours, polymerization was completed to obtain a dispersion of colored resin fine particles for aqueous ink (particle 1). The content of the cyclohexyl methacrylate monomer was 50.0% by mass relative to the total polymer components constituting the colored resin microparticles, and the content of the oil-soluble dye was 36.4% by mass relative to the total polymer components. The average particle size of the colored resin microparticles was 40 nm.

[0050] (Manufacturing example 2) In addition to using 340.5 parts of distilled water, 30 parts of cyclohexyl methacrylate monomer, and 45 parts of n-butyl methacrylate as the dyes in Production Example 1 above, an aqueous dispersion of colored resin fine particles for aqueous ink (particles 2) was obtained in the same manner as in Production Example 1 above. The content of the cyclohexyl methacrylate monomer was 31.6% by mass relative to the total polymer components constituting the colored resin fine particles, and the content of the oil-soluble dye was 46.3% by mass relative to the total polymer components. The average particle size of the colored resin fine particles was 82 nm.

[0051] Using the dispersions (particles 1 and 2) of the colored resin fine particles produced according to the above production examples 1 and 2, aqueous ink compositions 1 and 2 for writing instruments were prepared by conventional methods with the following formulations (total amount 100% by mass). Composition of inks 1 and 2: (Total amount 100% by mass) Dispersion of colored resin fine particles for aqueous ink according to manufacturing example 1 or 2, 50% by mass pH adjuster (triethanolamine) 1% by mass Water-soluble organic solvent (ethylene glycol) 5% by mass Ion-exchanged water 44% by mass

[0052] Viscosity (25°C): 3.5 mPa·s (Complete viscometer, TOKIMEC TV-20) Surface tension (25°C): 35 mN / m (Automatic surface tension meter, Kyowa Interface Science Co., Ltd., DY-300) Manufacturing example 1: Brightness of handwriting (lines) (L * Value): 73, Achromaticity C * :65 Manufacturing example 2: Brightness of handwriting (lines) (L * Value): 63, Achromaticity C * :65 Brightness of the pen nib when impregnated with ink (L * Value): Manufacturing example 1:38 Brightness of the pen nib when impregnated with ink (L * Value): Manufacturing example 2:35 Color difference between the handwriting (line) and the pen tip in manufacturing example 1: △E:35 Color difference between the handwriting (lines) and the pen tip in manufacturing example 2: △E:36 The color difference was measured using a VSS7700 micro-surface spectrophotometer manufactured by Nippon Denshoku Industries Co., Ltd.

[0053] In each writing instrument B of ink 1 and 2 using the pen tip A of Example 1 according to Figures 1 to 4, the writing instruments B comprise at least a holder 10 having a visible portion 13 that allows the writing direction to be seen, and a pen tip 20 attached to the holder 10, and at least the pen tip 20 has an opaque material (titanium oxide) fixed to it, L * a * b * (CIE LAB) Lightness (L) * The value is 90, and the achromaticity is C * The value is set to 10, and when writing on high-quality paper using this writing instrument, it was confirmed that, compared to conventional pen nibs 20 that do not contain opacity materials, the color development at the pen tip is enhanced, there is almost no difference in hue between the written line and the pen tip, and the color discrimination at the pen tip is improved. Furthermore, it was confirmed that by viewing the visible side through the visible part 13, it becomes easier to align the starting position of the pen stroke, and the writing instrument uses a pen tip that does not impair the appearance of the pen nib 20.

[0054] Furthermore, the protrusion amount Y = 0.85 mm from the tip of the writing lead 20 from the holder 10 is less than 1 mm. In particular, it was confirmed that when a right-handed person writes from left to right, the protruding part (protrusion amount) can be used to draw lines, and moreover, even when excessive load is applied, the writing performance is not impaired, and the writing lead does not break, resulting in a highly durable writing instrument.

[0055] Furthermore, when this writing instrument was set in an automatic writing device and tested according to the test method compliant with JIS S6037, a straight line was written on high-quality paper at a writing angle of 65°, a writing load of 1N, a speed of 7cm / s, and a distance of 50m. The condition of the written line was then visually inspected. It was found that because the above-mentioned preferred ink composition was used, the ink flow rate (5-20mg / m) was good, and while the drying of the pen tip was suppressed, the drying properties of the line and the low-temperature stability of the ink were excellent, resulting in a function that prevents bleeding and show-through of the line.

[0056] [Example 2] A writing instrument conforming to Figures 1-4 was used. The only difference from Example 1 is the configuration of the pen nib 20; otherwise, the configuration, ink composition, etc., are the same as in Example 1 and will be omitted. (Composition of 20 pen nibs) Polyethylene (PE) sintered core, 60% porosity (after concealing material fixation), writing section 22: W=4mm, knife-cut shape, ink guide section: φ(t)=1.6mm, protrusion Y=0.85mm (53% of t), protrusion Y' on the opposite side of protrusion Y=0.65mm (40% of t), writing core width X=1.75mm

[0057] (Manufacturing method for pen nibs) A sintered core was manufactured by blending polyethylene powder with an average particle size of 200 μm and titanium dioxide with an average particle size of 350 nm as an opacity material, followed by sintering. (Composition of 20 pen nibs) Polyethylene (PE) sintered core, (after sintering of concealing material) porosity 60%, writing section 22: W=4mm, knife-cut shape, ink guide section: φ(t)1.6mm, protrusion Y=0.85mm (53% of t), protrusion Y' on the opposite side of protrusion Y=0.65mm (40% of t), writing core width X=1.75mm

[0058] [Brightness of pen tip 20 (L * Value), achromaticity C * Measurement, etc. Pen nib 20 L * a * b * (CIE LAB) Lightness (L) * The achromaticity C value is measured using the following device. * The result was calculated. (Measuring equipment) Nippon Denshoku Industries Co., Ltd. VSS7700 Micro-surface Spectroscopic Colorimeter Pen tip 20 brightness (L * Value) = 90, achromaticity C * =10 Brightness of the pen nib when impregnated with ink (L * Value): Manufacturing example 1:40 Brightness of the pen nib when impregnated with ink (L * Value): Manufacturing example 2:36 Color difference between the handwriting (line) and the pen tip in manufacturing example 1: △E:33 Color difference between the handwriting (lines) and the pen tip in manufacturing example 2: △E:34

[0059] In each writing instrument B of ink 1 and 2 using the pen tip A of Example 2 according to Figures 1 to 4, the writing instruments B comprise at least a holder 10 having a visible portion 13 that allows the writing direction to be seen, and a pen tip 20 attached to the holder 10, and at least the pen tip 20 has an opaque material (titanium oxide) sintered and fixed to it, L * a * b * (CIE LAB) Lightness (L) * The value is 90, and the achromaticity is C * The value is set to 10, and when writing on high-quality paper using this writing instrument, it was confirmed that, compared to conventional pen nibs 20 that do not contain opacity materials, the color development at the pen tip is enhanced, there is almost no difference in hue between the written line and the pen tip, and the color discrimination at the pen tip is improved. Furthermore, it was confirmed that by viewing the visible side through the visible part 13, it becomes easier to align the starting position of the pen stroke, and the writing instrument uses a pen tip that does not impair the appearance of the pen nib 20.

[0060] Furthermore, in this second embodiment, the protrusion amount Y of the tip side of the writing lead 20 from the holder 10 was less than 1 mm, with Y = 0.85 mm. In particular, it was confirmed that when a right-handed person writes from left to right, the protruding part (protrusion amount) can be used to draw lines, and even when excessive load is applied, the writing performance is not impaired, and the writing lead does not break, resulting in a writing instrument with excellent durability. Moreover, when the writing instrument of this second embodiment was set in an automatic writing device and tested according to the test method compliant with JIS S6037, a straight line was written on high-quality paper at a writing angle of 65°, a writing load of 1N, a speed of 7 cm / s, and a distance of 50 m, and the state of the written line was visually checked. It was found that because the above-mentioned preferred ink composition was used, the ink flow rate (5-20 mg / m) was also good, and while the drying of the pen tip was suppressed, the drying properties of the line and the low-temperature stability of the ink were excellent, and the line exhibited the function of not bleeding or showing through to the other side. [Industrial applicability]

[0061] The pen tip of the present invention can be suitably applied as a pen tip for so-called marking pen type writing instruments, such as underline pens, paint markers, oil-based markers, and water-based markers. [Explanation of Symbols]

[0062] A Pen nib 10 Holder 20 Pen nibs 35 front axis 40 Ink absorbers 50 caps

Claims

1. A pen tip having a pen core containing an obscuring material, the pen core being L * a * b * (CIE LAB) color system lightness (L * A pen tip characterized by a value of 80 or more.

2. 2. The pen tip according to claim 1, wherein the concealing material is at least one selected from the group consisting of titanium oxide, zinc oxide, boron nitride, and barium sulfate, and has an average particle size of 50 to 1000 nm.

3. 3. The pen tip according to claim 1, wherein the pen tip is made of a sintered core or a fiber bundle core, and the concealing material is fixed to the sintered core or the fiber bundle core.

4. 4. A writing instrument equipped with the pen tip according to claim 1, wherein the writing instrument is loaded with a dye ink or a resin fine particle pigment ink containing a dye.

5. The lightness of the pen tip when it is saturated with ink (L * 5. The writing implement according to claim 4, wherein the value of the saturation coefficient is 30 or more.

6. 6. The writing implement according to claim 4, wherein the color difference ΔE between the written line and the pen core is less than 40.

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