Notebook

Abstract

To provide a writing instrument that can improve ink diffusion, prevent ink spurting, and stabilize ink flow. [Solution] The device comprises a shaft cylinder and a filling housed inside the shaft cylinder, wherein the pore diameters of the central part, at least a portion of the outer circumference, and other parts differ in a plane perpendicular to the axial direction of the shaft cylinder, with the pore diameters of the central part being smaller than those of the other parts, and the pore diameters of at least a portion of the outer circumference being larger than those of the other parts.

Description

Technical Field

[0004] , , ,

[0005] , ,

[0001] The present invention relates to a writing instrument provided with a wick (ink absorber) impregnated with ink.

Background Art

[0002] Generally, the wick of a writing instrument is formed by immersing a string-like fiber bundle body, in which convergent fibers are adhered with a binder, in ink, covering the string-like fiber bundle body immersed in ink with an outer skin made of resin, and cutting it to a predetermined length (see, for example, Patent Document 4 and Patent Document 5). Here, in order to prevent ink from spraying out, a writing instrument in which an air escape path is formed in the wick (see, for example, Patent Document 1), and in order to improve the diffusibility of ink and stabilize the ink flow rate, a writing instrument having a wick in which a dense portion with a low porosity is arranged closer to the axis and a sparse portion with a high porosity is arranged around the axis in the radial cross section of the wick (see, for example, Patent Document 2 and Patent Document 3) have been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional technology, it has been difficult to sufficiently and effectively achieve improvement in the diffusibility of ink, prevention of ink spraying, and stabilization of the ink flow rate.

[0005] The object of the present invention is to provide a writing instrument that can improve ink diffusion, prevent ink from squirting, and stabilize ink flow rate. [Means for solving the problem]

[0006] The inventors have completed the present invention in order to solve the above problems. The present invention provides the following:

[0007] (1) The invention is characterized by comprising a shaft cylinder and a filling housed inside the shaft cylinder, wherein the pore diameters of the central part, at least a portion of the outer circumference, and other parts differ in a plane perpendicular to the axial direction of the shaft cylinder, with the pore diameters of the central part being smaller than those of the other parts, and the pore diameters of at least a portion of the outer circumference being larger than those of the other parts. Furthermore, it is preferable that the pore diameter of the central portion is 50 to 90 μm, the pore diameter of the other portions is 80 to 120 μm, and the pore diameter of at least a portion of the outer periphery is 100 to 140 μm. (2) The filling is characterized in that it has two or more portions on its outer circumference that have a pore diameter larger than the pore diameter of the other portions. (3) The filling is characterized by having pore diameters that vary in the axial direction. Furthermore, it is preferable that the pore diameter of the other parts increases in a stepwise manner in the axial direction, from the downward-facing part to the upward-facing part when in use. Furthermore, it is preferable that the padding be formed by powder bed fusion manufacturing. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a writing instrument that can improve ink diffusion, prevent ink from squirting, and stabilize ink flow rate. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view showing the appearance of a writing instrument according to the first embodiment. [Figure 2] (a) a front longitudinal section view and (b) a plan transverse section view of a writing instrument according to the first embodiment. [Figure 3] (a) is a cross-sectional view and (b) is a front longitudinal cross-sectional view of the padding according to the first embodiment. [Figure 4] (a) an oblique view, (b) a front view, (c) a front longitudinal section view, (d) a left side view, and (e) a right side view of a writing instrument according to the second embodiment. [Figure 5] The following are (a) a perspective view, (b) a front view, (c) a front longitudinal section view, (d) a left side view, and (e) a right side view of a writing instrument according to the second embodiment, showing the cap removed. [Figure 6] The following are (a) a perspective view, (b) a front view, (c) a front longitudinal section view, (d) a left side view, and (e) a right side view of the front shaft according to the second embodiment. [Figure 7] These are (a) a perspective view, (b) a front view, (c) a front longitudinal section view, (d) a left side view, and (e) a right side view of the rear shaft according to the second embodiment. [Figure 8] (a) a front view and (b) a perspective view of the writing section according to the second embodiment. [Figure 9] The following are (a) a perspective view, (b) a perspective view, (c) a plan view, (d) a front view, (e) a left side view, (f) a right side view, and (g) a front longitudinal cross-sectional view of the central axis according to the second embodiment. [Figure 10] This figure shows an example of the padding configuration according to another embodiment, where (a) is a cross-sectional view and (b) is a front longitudinal cross-sectional view. [Figure 11] This figure shows an example of a case where the batting according to another embodiment is molded by powder bed fusion manufacturing. [Figure 12] This figure shows an example of a case where the batting according to another embodiment is molded by powder bed fusion manufacturing. [Modes for carrying out the invention]

[0010] Hereinafter, referring to the drawings, a writing instrument (twin-type sign pen) according to the first embodiment of the present invention will be described. FIG. 1 is a perspective view showing the appearance of the writing instrument 10 according to the first embodiment, FIG. 2 is a view showing a cross section of the writing instrument 10, FIG. 2(a) is a front longitudinal cross-sectional view, and FIG. 2(b) is a plan cross-sectional view. In FIG. 2, illustration of the porous body 23 constituting the middle cotton 22 described later is omitted.

[0011] As shown in FIG. 1, the writing instrument 10 includes a writing instrument body (shaft cylinder) 12, a flat pen tip 14 having a visible part provided at one end of the writing instrument body 12, and a rod-shaped pen tip 16 provided at the other end of the writing instrument body 12. The writing instrument 10 also includes a detachable cap 18 for protecting the pen tip 14 and a detachable stand-type cap 20 for protecting the pen tip 16. The writing instrument body 12, the cap 18, and the stand-type cap 20 constituting the writing instrument 10 are formed of metal, melamine resin, or the like.

[0012] Here, the cap 18 is formed of a cylindrical body with one end open and the other end closed. Also, as shown in FIGS. 2(a) and 2(b), the stand-type cap 20 is composed of a cap body 20a and a stand portion 20b integrally connected to the outer surface of the cap body 20a. The cap body 20a is formed of a cylindrical body with one end open and the other end closed. The stand portion 20b is a cylindrical body with one end open and the outer diameter increasing from the other end toward the one end. The opening at one end of the cap body 20a is connected to the other end of the stand portion 20b, and the closed other end of the cap body 20a is located inside the one end of the stand portion 20b. Therefore, the stand-type cap 20 functions as a stand by placing one end of the stand portion 20b on an installation surface.

[0013] The writing instrument body 12 is composed of a cylindrical body, and a gripping indication surface 12a for making the direction of the flat pen tip 14 easy to understand is formed on the outer wall on the pen tip 14 side.

[0014] The writing instrument body 12 contains a cotton wick 22 for storing ink. Examples of fibers that can be used for the cotton wick 22 include one or more combinations of polyacetal resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, polyolefin resin, polyvinyl resin, polycarbonate resin, polyether resin, and polyphenylene resin.

[0015] The composition of the ink stored in the cotton batting 22 is not particularly limited, and may include oil-based ink, water-based ink, etc. Furthermore, as an example of an ink, an associative agent may be included in the ink to prevent particle sedimentation within the cotton batting 22. Examples of associative agents include at least one of methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylethylmethylcellulose, and hydroxypropylmethylcellulose. Particularly preferred is hydroxyethylcellulose due to its good particle association properties.

[0016] A front barrel 13 is attached to the tip 14 side of the writing instrument body 12, to which the tip 14 is fixed. The tip 14 fixed to the front barrel 13 comprises a writing portion 14a made of a porous material, which includes a writing portion 14a1 for writing and an ink guiding portion 14b1 for guiding ink to the writing portion 14a1, and a holder 14b having a visible portion. The rear end of the holder 14b is fixed inside the opening of the front barrel 13 of the writing instrument body 12. The writing portion 14a1 is fixed to the tip side of the holder 14b, and the ink guiding portion 14a2 is fixed along the underside of the holder 14b (the underside in Figure 2(b)).

[0017] The ink-guiding portion 14a2 is in the shape of a thin plate and has an inclined portion toward the cotton wick 22. It is preferable that its cross-section be rectangular or elliptical in shape in order to maximize (widen) the visible area. In this embodiment, the cross-section is formed in a rectangular shape. The inclined portion of the ink-guiding portion 14a2 toward the cotton wick 22 is inserted into the cotton wick 22, and its tip is connected to the writing portion 14a1 via the holder 14b.

[0018] The pen tip 16 of the writing instrument body 12 comprises a thin-line type rod-shaped writing section 16a and a holding section 16b that holds the writing section 16a, with the holding section 16b fitted to the pen tip 16 side of the writing instrument body 12. The writing section 16a is made of a porous material, and the end of the rod-shaped writing section 16a on the cotton wick 22 side is inserted into the cotton wick 22. The writing sections 14a and 16a have different pore sizes (capillary force) than the cotton wick 22. That is, the writing sections 14a and 16a have stronger capillary force than the cotton wick 22.

[0019] Figure 3 shows a cross-section of the cotton batting 22. Figure 3(a) is a cross-sectional view AA showing the cotton batting 22 cut along the cutting line shown in Figure 3(b), and Figure 3(b) is a front longitudinal cross-sectional view. The cotton batting 22 consists of a columnar porous body 23 in which ink is stored and an outer skin 24 such as a resin film covering the sides of the porous body 23, and is formed by powder bed fusion manufacturing using a 3D printer. In the porous body 23 of the cotton batting 22, the pore diameter of the central part 23a, the pore diameter of the four regions 23b, 23c, 23d, and 23e located on the outer periphery, and the pore diameter of the other parts 23f are different on a surface perpendicular to the axial direction (longitudinal direction) of the writing instrument body 12 (cross-section shown in Figure 3(a)). Specifically, the pore diameter of the central part 23a is smaller than the pore diameter of the other parts 23f, in the range of 50 to 90 μm, and in this embodiment it is 70 μm. The pore diameters of regions 23b, 23c, 23d, and 23e are larger than those of the other portion 23f, and are in the range of 100 to 140 μm, which is 120 μm in this embodiment. The pore diameters of the other portion 23f are 80 to 120 μm, which is 100 μm in this embodiment.

[0020] In this embodiment, the case where the cross-sectional shape of the central portion 23a is rectangular as shown in Figure 3(a) is given as an example, but it may be a circular shape or other shape. Also, in this embodiment, there are four portions (regions 23b, 23c, 23d, 23e) located on the outer periphery with pore diameters larger than the pore diameters of the central portion 23a and the other portions 23f, but it may be a configuration with one to three or five or more such portions. Also, the case where the cross-sectional shapes of the four regions 23b, 23c, 23d, 23e are substantially rectangular as shown in Figure 3(a) is given as an example, but they may be a circular shape or other shape other than the shape shown in Figure 3(a).

[0021] In this first embodiment of the writing instrument, since the pore diameter of the central part 23a in the porous body 23 of the cotton wick 22 is smaller than the pore diameter of the other parts 23f, the capillary force of the central part 23a is stronger than the capillary force of the other parts 23f. Therefore, when ink is supplied from the central part 23a to the writing parts 14a and 16a, the ink held in the other parts 23f moves to the central part 23a. That is, the diffusion of ink can be improved and the ink flow rate can be stabilized from the other parts 23f to the central part 23a and from the central part 23a to the writing parts 14a and 16a, thereby preventing streaking. Furthermore, since the pore diameters of the regions 23b, 23c, 23d, and 23e located on the outer periphery of the porous body 23 of the cotton wick 22 are larger than the pore diameter of the other parts 23f, the capillary force of regions 23b, 23c, 23d, and 23e is weaker than the capillary force of the other parts 23f. Therefore, the ink is held in the central part 23a and the other parts 23f, which have stronger capillary forces than areas 23b, 23c, 23d, and 23e, and it is possible to have no ink or only a small amount of ink in areas 23b, 23c, 23d, and 23e. As a result, even if the air inside the cotton wick 22 expands due to a rise in temperature when the user grips the writing instrument 10, the expanded air can be released into areas 23b, 23c, 23d, and 23e, preventing ink from squirting out.

[0022] Next, a writing instrument (single-type direct-ink felt-tip pen) according to a second embodiment of the present invention will be described. Figure 4 is a diagram showing the configuration of the writing instrument 30 according to the second embodiment, where Figure 4(a) is a perspective view, Figure 4(b) is a front view, Figure 4(c) is a front longitudinal section view, Figure 4(d) is a left side view, and Figure 4(e) is a right side view. Figure 5 is a diagram showing the configuration of the writing instrument 30 with the cap 31 removed, where Figure 5(a) is a perspective view, Figure 5(b) is a front view, Figure 5(c) is a front longitudinal section view, Figure 5(d) is a left side view, and Figure 5(e) is a right side view.

[0023] The writing instrument 30 according to the second embodiment comprises a container body (shaft) 32, the container body 32 consisting of a front shaft 34 and a rear shaft 36. The front shaft 34 and the rear shaft 36 are fitted together and fixed in place. Figure 6 shows the configuration of the front shaft 34, where Figure 6(a) is a perspective view, Figure 6(b) is a front view, Figure 6(c) is a front longitudinal section view, Figure 6(d) is a left side view, and Figure 6(e) is a right side view. The front shaft 34 has a main body portion 42 which is a cylindrical body that houses the cotton wick 38 via a central shaft 40, and a tip portion 44 which tapers towards the tip of the main body portion 42, and the rear outer circumference of the main body portion 42 has a fitting surface portion 46 for fitting and fixing the rear shaft 36. The inner circumference of the tip section 44 is provided with a convex fitting section 50 for attaching the writing section 48 (see Figures 4 and 5), and the outer circumference is provided with a rotating surface section 52 for rotatably attaching the cap 31 (see Figure 4).

[0024] Figure 7 shows the configuration of the rear shaft 36, where Figure 7(a) is a perspective view, Figure 7(b) is a front view, Figure 7(c) is a front longitudinal section view, Figure 7(d) is a left side view, and Figure 7(e) is a right side view. The rear shaft 36 is composed of a bottomed cylindrical body with its rear end sealed. The inner circumferential surface of the front end opening 54 has a fitting portion 56 for fitting and fixing with the fitting surface portion 46 (see Figure 6) of the front shaft 34, and a press-fit portion 58 for press-fitting the middle shaft 40 (see Figures 4 and 5) is provided on the rear side of the front end opening 54. Ink is contained inside the rear shaft 36, and if the rear shaft 36 is made of a transparent or translucent material that provides visibility, the remaining ink level can be visually inspected.

[0025] As shown in the front view of Figure 8(a) and the perspective view of Figure 8(b), the writing section 48 is bullet-shaped and has a front section 61, a central section 62, a contact section 63 that contacts the cotton wick 38 (see Figures 4 and 5), and a circumferentially concave fitting groove 64 between the front section 61 and the central section 62 for fitting into the fitting section 50 of the front shaft 34 (see Figure 6). The writing section 48 only needs to be made of a material that has capillary action and can volatilize ink when supplied. For example, it can be made of a porous material with pores, specifically a sponge, sintered body, fiber bundle, foam, sponge, felt, porous body, or a structure with a channel having capillary action inside. Examples of shapes include cylindrical, bullet-shaped, prismatic, pen-nib-shaped, elliptical, and rectangular prismatic.

[0026] The cap 31 is made up of a cylindrical body with a sealed tip, and by attaching its rear opening to the rotating surface portion 52 of the front shaft 34, it fits with the container body 32 at the tip of the front shaft 34.

[0027] Figure 9 shows the configuration of the central shaft 40, where Figures 9(a) and (b) are perspective views, Figure 9(c) is a plan view, Figure 9(d) is a front view, Figure 9(e) is a left side view, Figure 9(f) is a right side view, and Figure 9(g) is a front longitudinal cross-sectional view. The central shaft 40 is a cylindrical member for attaching the cotton batting 38 inside the container body 32. The press-fit surface portion 71 on the outer circumference of the central shaft 40 is press-fitted into the rear shaft 36, and ink from inside the rear shaft 36 flows into the rear interior 75 of the central shaft 40. Inside the central shaft 40 are an ink guide tube 72 through which the ink from inside the rear shaft 36 passes by capillary action, and an air exchange tube 73 through which replacement air passes to the rear shaft 36 side. The ink guide tube 72 and the air exchange tube 73 are inserted behind the cotton batting 38.

[0028] The cotton core 38 temporarily stores ink that has moved from inside the rear shaft 36 to the rear interior 75 of the central shaft 40 via the ink guide tube 72 of the central shaft 40 at its front. The cotton core 38 also supplies the ink temporarily stored at its front to the writing section 48 via the contact portion 63 of the writing section 48, which is in contact (including joining) with the cotton core 38 at its front. The cotton core 38, like the cotton core 22 in the first embodiment (see Figure 3), consists of a columnar porous body in which ink is temporarily stored and an outer skin such as a resin film covering the sides of the porous body, and is molded by powder bed fusion using a 3D printer. The structure of the porous body and outer skin of the cotton core 38 is the same as that of the porous body 23 and outer skin 24 shown in Figure 3, so a description of them is omitted.

[0029] According to this second embodiment of the writing instrument, by providing a cotton core 38 inside the container body 32, ink can be temporarily stored, thus preventing the ink contained in a liquid state inside the rear shaft 36 from squirting out in response to temperature changes. Furthermore, in the porous body of the cotton core 38, when ink is supplied from the central part to the writing part 48, the ink held in the other parts moves to the central part. This improves the diffusion of ink from the other parts to the central part and from the central part to the writing part 48, stabilizing the ink flow rate and preventing streaking. In addition, in the porous body of the cotton core 38, the ink is held in the central part and the other parts, which have stronger capillary force than the four regions, and the four regions can be kept free of ink or have a small amount of ink. Therefore, even if the air inside the cotton core 38 expands due to a temperature rise, such as when the user grips the writing instrument 30, the expanded air can be released into the four regions, preventing ink from squirting out.

[0030] In the embodiments described above, we have explained using as an example a batting 22, 38 having a porous body in which the central part, four regions located on the outer periphery, and other parts have different pore diameters in a plane perpendicular to the axial direction. However, as shown in Figures 10(a) and (b), the batting 80 may also have a porous body 82 in which the pore diameter gradually increases from the central part to the outer periphery in a plane perpendicular to the axial direction. Figure 10 is a diagram showing an example of the configuration of the batting 80 according to another embodiment, where Figure 10(a) is a BB cross-sectional view and a side longitudinal cross-sectional view showing a cross-section of the batting 80 cut along the cutting line shown in Figure 10(b), and Figure 10(b) is a front longitudinal cross-sectional view. Figure 11 is a diagram showing an example of molding the batting 80 shown in Figure 10 by powder bed fusion using a 3D printer. As shown in Figure 10, the batting 80 consists of a columnar porous body 82 in which ink is stored and an outer skin 83 such as a resin film covering the sides of the porous body 82. In the porous body 82 of the padding 80, the pore diameter is smallest in the central part 82a (70 μm), and the pore diameter gradually increases in the concentric circular regions 82b, 82c, and 82d centered on the central part 82, with the pore diameter being largest in the concentric circular outer peripheral part 82e centered on the central part 82 (120 μm). As shown in Figure 11, the material for the porous body 82 is extruded from the nozzle 85a of the 3D printer, and the material for the outer shell 83 is extruded from the nozzle 85b into a groove in the base 86 which has a semicircular groove (round groove) formed by cutting the shape of the padding 80 horizontally down the center. As nozzles 85a and 85b move in the axial and radial directions, the porous body 82 and outer shell 83 are gradually formed in the order shown in Figures 11(a) to (e), and finally the padding 80 is completed.

[0031] In addition, instead of the padding 22 shown in Figure 3, the padding 38 shown in Figures 4 and 5, and the padding 80 shown in Figure 10, the padding may be made of a porous material in which the pore size increases in a gradient from the center to the outer edge in a plane perpendicular to the axial direction.

[0032] Furthermore, in the second embodiment described above, the case in which the porous body of the padding 38 has different pore diameters in a plane perpendicular to the axial direction was given as an example, but a configuration with pore diameters that change in the axial direction is also possible. For example, the pore diameter of other parts of the padding 38 may be configured to increase in stages in the axial direction from the part that is downward (towards the writing part 48) when the writing instrument 30 is in use to the part that is upward (towards the rear inner side 75 of the central shaft 40). Alternatively, for example, instead of padding 38, a configuration may be provided in which the pore diameter increases in stages in the axial direction from the part that is downward to the part that is upward when the writing instrument 30 is in use. Specifically, the pore diameter of the padding is molded to increase in stages from 70 μm to 120 μm. Figure 12 shows an example of molding padding with a pore diameter that increases in stages in the axial direction using powder bed fusion 3D printing. As shown in Figures 12(a) and (b), first the outer shell 93 is set on the cylindrical base 95, and the support base 96 is inserted into the cylindrical base 95. The cylindrical base 95 is a base for forming the columnar padding 90, and the support base 96 has a disc that is inscribed on the inner surface of the cylindrical base 95. Next, as shown in Figures 12(c) to (g), the process of lowering the support base 96 to a predetermined position relative to the cylindrical base 95 and the process of extruding the porous body 92 material from the nozzle 97 of the 3D printer are repeated, thereby forming layers 92a to 92g of the porous body 92 (pore diameter: 92a = 70 μm < 92b < 92c < 92d < 92e < 92f < 92g = 120 μm), and finally the padding 90 is completed. The thickness of layers 92a to 92g is not limited to the thickness shown in Figure 12, and can be changed as appropriate.

[0033] Alternatively, instead of the cotton batting 90 shown in Figure 12, the cotton batting 38 may be provided with a porous material in which the pore diameter of the remaining portion 23f of the cotton batting 38 increases in a axial gradient from the lower portion to the upper portion when the writing instrument 30 is in use. Furthermore, instead of the cotton batting 38 and cotton batting 90, the cotton batting may be provided with a porous material in which the pore diameter increases in a axial gradient from the lower portion to the upper portion when the writing instrument 30 is in use, and the pore diameter remains constant in the radial direction. As with the cotton batting 90 described above, by changing the pore diameter in a stepwise or gradual manner in the axial direction, the capillary force and ink retention force can be changed within the cotton batting, thereby further improving ink diffusion, preventing ink spurting, and stabilizing ink flow. [Industrial applicability]

[0034] This invention makes it possible to manufacture a batting material having a porous body composed of different pore sizes in different parts in order to obtain varying capillary force, and the writing instrument equipped with this batting material has industrial applicability. [Explanation of Symbols]

[0035] 10,30…Writing instrument, 12…Writing instrument body, 13,34…Front barrel, 14,16…Pen nib, 14a,16a…Writing section, 14b,16b…Holder, 18,31…Cap, 20…Stand-type cap, 40…Inner cylinder, 22,38,80,90…Cotton, 23,82,92…Porous material, 23a,82a…Central part, 23b~23e,82b~82e…Cotton area, 23f…Other areas, 24,83,93…Outer shell, 32…Container body, 36 ...rear shaft, 40...middle shaft, 42...main body, 44...tip section, 46...fitting surface, 48...writing section, 50...fitting section, 52...rotating surface, 54...tip side opening, 56...fitting section, 58...press-fit section, 61...front section, 62...center section, 63...contact section, 64...fitting groove, 71...press-fit surface, 72...ink guide tube, 73...air exchange tube, 75...rear side interior, 76...rear side opening, 85a, 85b, 97...nozzle, 86...base, 95...cylindrical base, 96...support base.

Claims

1. The barrel and, A filling material housed inside the aforementioned shaft cylinder, wherein the pore diameters of the central part, at least a portion of the outer circumference, and other parts differ in a plane perpendicular to the axial direction of the shaft cylinder, with the pore diameters of the central part being smaller than those of the other parts, and the pore diameters of at least a portion of the outer circumference being larger than those of the other parts, A writing instrument characterized by having the following features.

2. The writing instrument according to claim 1, characterized in that the cotton filling has two or more portions on its outer circumference having a pore diameter larger than the pore diameter of the other portions.

3. The writing instrument according to claim 1 or 2, characterized in that the cotton filling has a pore diameter that changes in the axial direction.

Images