Writing implement

Abstract

To provide a writing implement capable of continuously and stably ejecting high-viscosity ink containing coarse particles with the same writing action as that of a normal writing implement.SOLUTION: A writing implement 1 according to the present invention is provided with an ejection mechanism 11 that includes a barrel 11a and a nib portion 11b housed within the barrel 11a and projecting its tip from the tip opening of the barrel 11a, and that ejects ink from the tip. The writing implement 1 further includes a pressure mechanism 12 that includes an ink reservoir 12a attached to the ejection mechanism 11 and a compression portion 12b that applies a constant pressure to the ink contained in the ink reservoir 12a. The nib portion 11b functions as a valve that opens and closes the ink flow path, and is tilted relative to the central axis of the barrel 11a by the writing pressure during the writing action, opening the valve and ejecting ink that has flowed into the ink flow path from the tip.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a writing implement that enables writing with highly viscous ink containing coarse particles. [Background technology]

[0002] Sand letter boards have been commercially available as educational tools that allow children to learn characters by tracing the rough characters with their fingers and pronouncing them. However, while these tools are highly tactilely readable, they are expensive and do not offer a large number of selectable characters (hiragana, katakana, alphabet, etc.), making them unsuitable for learning characters such as kanji.

[0003] In order to increase the number of characters, some people create handmade letter boards using pens that contain particles (glitter) in a paste-like ink or pens that expand when the ink dries (the lines harden to a certain thickness), and use these as teaching tools for learning to read. However, while these teaching tools are inexpensive and allow for the number of characters to be increased freely, they are less tactilely legible than sand letter boards.

[0004] For example, the performance required for teaching materials for character learning is that they are highly legible, inexpensive, and can freely draw fine lines (such as kanji characters). In particular, to achieve excellent tactile readability, there is a demand for writing instruments that can draw lines using high-viscosity ink containing coarse particles.

[0005] The following Patent Documents 1 to 5 disclose various ink ejection mechanisms as examples of writing implements that can express lines with highly viscous ink.

[0006] For example, Patent Document 1 describes a valve structure for a ballpoint pen tip in which, when not in use, a hard ball abuts against the tip of a rod of an inner seal body, and the inner seal body completely seals the ink outlet hole with the elastic force of a spring, preventing the flow of highly viscous ink. Furthermore, Patent Document 1 describes that when writing pressure is applied to the hard ball, the ball retracts together with the inner seal body against the elastic force of the spring, releasing the inner seal and allowing highly viscous ink to flow out, thereby enabling writing.

[0007] Furthermore, Patent Document 2 describes the structure of a drawing pen, in which a valve is built into the pen tip for opening and closing an ink flow path from a reservoir formed in the pen shaft to the pen tip. Furthermore, Patent Document 2 describes that the valve opens when a needle-shaped operator that is biased to protrude from the pen tip retracts into the pen tip against the biasing force, and that when writing pressure is applied and the needle operator retracts, a flow path for high-viscosity ink is formed in the gap between the needle operator and the inner peripheral surface of the pen tip.

[0008] Furthermore, Patent Document 3 describes a valve structure for an applicator for high-viscosity liquid agents, in which an applicator hole is formed at the tip of the applicator, and the tip of a conical valve body protrudes outward from the applicator hole due to the biasing force of a coil spring. Furthermore, Patent Document 3 describes that by pressing the tip of the valve body against the surface of the object to be coated and pushing the valve body deep inside against the biasing force of the coil spring, a gap is formed between the valve body and the inner surface of the tip of the applicator, and the high-viscosity liquid agent (high-viscosity ink) flows out from this gap to the outside.

[0009] Patent document 4 also describes a paint marker that includes a cylindrical fixed part attached to a tip opening, and a movable pen that is slidably inserted into this fixed part, and when the tip, which is exposed from the fixed part by the spring force, retracts to the same level as the tip of the fixed part due to writing pressure on the writing surface, the valve mechanism is opened and high-viscosity ink is released from the gap with the fixed part.

[0010] Furthermore, Patent Document 5 describes an extrusion tube-type writing instrument that has a structure in which the high-viscosity ink in the tube is automatically extruded by the force of a spring, and the lower end of the inner surface of the pen tip and the ball form a valve, and the high-viscosity ink is extracted by pressing the ball against the object being written on. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 7-39804 [Patent Document 2] Japanese Patent Application Publication No. 60-124298 [Patent Document 3] Japanese Utility Model Application Publication No. 59-138557 [Patent Document 4] Japanese Utility Model Application Publication No. 58-94573 [Patent Document 5] Japanese Patent Application Publication No. 11-319691 Summary of the Invention [Problem to be solved by the invention]

[0012] As described in the above-mentioned patent documents, conventionally, a valve structure has been adopted in which the valve body is opened by pressing the pen tip (tip) in the axial direction. That is, an ink ejection mechanism is generally used in which the pen tip is pressed in the axial direction to form a gap between the inner surface of the tip and the valve body, thereby ejecting high-viscosity ink from the outside of the pen tip.

[0013] However, in the valve structure described in the above-mentioned patent documents, there is a limit to the size of the gap formed by pressing the pen tip. For example, when using a highly viscous ink containing coarse particles (such as silica sand of about 0.2 mm) to obtain excellent tactile readability, clogging of the particles occurs frequently, making stable and continuous writing (discharging of ink) difficult.

[0014] Furthermore, as in the above-mentioned patent documents, when writing by ejecting highly viscous ink from the gap formed by pressing the pen tip (tip) into the paper surface, the highly viscous ink does not easily spread over the paper surface, and the amount of ink ejected is not stable depending on how much the pen tip is pressed, so the thickness of the ink is not constant, and line cracks occur in areas where the amount of ink ejected is low, making it difficult to produce clean lines.

[0015] Furthermore, the writing action using the writing instrument described in the above patent document, i.e., the writing action using a writing instrument having a valve structure that ejects ink by pressing the pen tip in the axial direction, is different from the writing action using a normal writing instrument, in which pressure is applied in a direction other than the axial direction (for example, vertically when the writing instrument is tilted), and therefore it is difficult to write neat letters or pictures.

[0016] Furthermore, in the case of a writing instrument such as that described in Patent Document 5 above, which has a structure in which high-viscosity ink in a tube is automatically pushed out by a spring force, as the ink decreases, the spring force (load) also gradually weakens, making it difficult to continuously obtain a constant amount of ink ejected.

[0017] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a writing instrument that allows writing while continuously and stably ejecting high-viscosity ink containing coarse particles with the same writing action as a normal writing instrument. [Means for solving the problem]

[0018] The writing instrument according to the present invention comprises a barrel and a nib portion housed within the barrel and projecting its tip from a distal end opening of the barrel, and is equipped with an ejection mechanism for ejecting ink from the tip. The writing instrument further comprises an ink reservoir attached to the ejection mechanism, and a pressure mechanism having a compression unit that applies a constant pressure to the ink contained in the ink reservoir. The nib portion functions as a valve for opening and closing an ink flow path, and is tilted relative to the central axis of the barrel by the writing pressure during writing, thereby opening the valve and ejecting ink that has flowed into the ink flow path from the tip.

[0019] This allows high-viscosity ink containing coarse particles to be continuously and stably ejected with the same writing action as with a normal writing implement.

[0020] In the writing implement configured as described above, the nib portion comprises a valve body having a long, thin, cylindrical capillary portion that forms an ink flow path therein and a disk-shaped valve portion provided at one end of the capillary portion for opening and closing the ink flow path, and when the valve is open, ink pressurized with a certain force by the compression portion is ejected from an ink outlet hole formed at the tip portion, which is the other end of the capillary portion. Meanwhile, the nib portion comprises an elastic body having a restoring force for returning the nib portion to its original position when tilted by writing pressure, and when the writing action is finished, the restoring force of the elastic body causes the valve to close, stopping the ejection of ink.

[0021] In the writing implement configured as described above, it is preferable that the elastic body is a coil spring. It is also preferable that a pipe is attached to the thin tube portion so as to be in close contact with the inner wall of the thin tube portion to protect the thin tube portion from writing pressure.

[0022] Furthermore, in the writing instrument configured as described above, the barrel has a cylindrical portion and a tapered portion that tapers from one end of the cylindrical portion. A male screw formed on the outer peripheral surface of the cylindrical compressed portion and a female screw formed on the inner wall of the cylindrical portion are screwed together, and the compressed portion is further screwed into the barrel by further screwing, thereby pressurizing the ink contained in the ink reservoir with a constant force.

[0023] The ink used in the writing instrument according to the present invention is preferably a high-viscosity ink containing coarse particles. Specifically, the high-viscosity ink in the present invention refers to an ink composition having a viscosity of 10 Pa·s or more at room temperature (25°C). [Effects of the Invention]

[0024] According to the writing implement of the present invention, it is possible to continuously and stably eject highly viscous ink containing coarse particles with the same writing action as with a normal writing implement. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a diagram showing one embodiment of a writing instrument according to the present invention. [Figure 2] FIG. 2 is a diagram showing an embodiment of a writing instrument according to the present invention. [Figure 3] FIG. 3 is a diagram showing an embodiment of a writing instrument according to the present invention. [Figure 4] FIG. 4 is a diagram showing an embodiment of a writing instrument according to the present invention. [Figure 5] FIG. 5 is a diagram showing an embodiment of a writing instrument according to the present invention. [Figure 6] FIG. 6 is a diagram showing an embodiment of a writing implement according to the present invention. [Figure 7] FIG. 7 is a diagram showing a state in which the discharge mechanism and the pressure mechanism that constitute the writing implement according to the present invention are separated. [Figure 8] FIG. 8 is an exploded view of the discharge mechanism section. [Figure 9]FIG. 9 is an enlarged view showing an example of the structure and shape of the valve body. [Figure 10] FIG. 10 is a diagram showing an example of the structure and shape of the spring receiver. [Figure 11] FIG. 11 is an exploded view of the pressurizing mechanism. [Figure 12] FIG. 12 is an exploded view of the pressurizing mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0026] The writing instrument according to the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments. Furthermore, in the specification and drawings of the present application, elements that can be similarly described may be designated by the same reference numerals, and redundant description may be omitted.

[0027] <Writing instrument composition> 1 to 6 are diagrams showing one embodiment of a writing instrument according to the present invention. In detail, FIG. 1(a) is a front view showing the appearance of the writing instrument with the cap attached, and FIG. 1(b) is a cross-sectional view of the writing instrument shown in FIG. 1(a). Also, FIG. 2(a) is a front view showing the appearance of the writing instrument in the initial state (before ink has been used) with the cap removed, and FIG. 2(b) is a cross-sectional view of the writing instrument shown in FIG. 2(a). Also, FIG. 3(a) is a front view showing the appearance of the writing instrument in the final state (after ink has been used) with the cap removed, and FIG. 3(b) is a cross-sectional view of the writing instrument shown in FIG. 3(a). Also, FIG. 4(a) is a perspective view of the writing instrument shown in FIG. 2(a), and FIG. 4(b) is a perspective view of the writing instrument shown in FIG. 3(a). Also, FIG. 5(a) is a front view showing the appearance of the writing instrument during writing, and FIG. 5(b) is a cross-sectional view of the writing instrument shown in FIG. 5(a). 6(a) is a partially enlarged view of the cross section shown in FIG. 2(b), and FIG. 6(b) is a partially enlarged view of the cross section shown in FIG. 5(b).

[0028] In this embodiment, a writing implement for writing sand letters is used as an example, and the ink for writing sand letters (hereinafter referred to as sand ink) has, for example, a sand particle diameter φ of 0.2 to 0.4 mm and a viscosity of approximately 50,000 mPa·S (high viscosity) without sand. Details of the composition of the sand ink will be described later.

[0029] The writing instrument 1 of this embodiment includes an ejection mechanism 11 that ejects sand ink and a pressure mechanism 12 that pressurizes the sand ink. For example, the ejection mechanism 11 has a barrel 11a and a nib 11b whose tip protrudes outward from the tip opening of the barrel 11a, and ejects sand ink from the tip of the nib 11b. The pressure mechanism 12 has an ink reservoir 12a that is fixed to the ejection mechanism 11 by screwing, and a compression mechanism 12b that pressurizes the sand ink stored in the ink reservoir 12a. The writing instrument 1 is structured so that the tip of the ejection mechanism 11 (nib 11b) is protected by a cap 13 (see FIG. 1).

[0030] In this writing instrument 1, the compression section 12b applies a constant pressure to the sand ink contained in the ink reservoir 12a (the structure for applying a constant pressure to the sand ink will be described in detail later), and the pen tip section 11b, housed at the tip end of the barrel 11a, functions as a valve that opens and closes the flow path of the sand ink. For example, when writing begins, a constant amount of sand ink pressurized with a constant pressure by the compression section 12b flows out of the pen tip section 11b, which is in an open state. When writing ends, the valve closes and the flow of sand ink from the pen tip section 11b stops. This structure allows the writing instrument 1 to constantly eject a constant amount of sand ink only when writing.

[0031] The writing action using the writing instrument 1 of this embodiment is a normal writing action in which the writing instrument is tilted and pressure is applied vertically toward the surface of paper, etc. In other words, the writing instrument 1 of this embodiment does not employ a conventional valve structure in which the valve body is opened by pressing the tip in the axial direction.

[0032] 7A and 7B are diagrams showing the state in which the discharge mechanism unit 11 and the pressure mechanism unit 12 constituting the writing instrument 1 of this embodiment are separated, with FIG. 7A being an oblique view of the state in which the discharge mechanism unit 11 and the pressure mechanism unit 12 are separated, FIG. 7B being a front view of the state in which the discharge mechanism unit 11 and the pressure mechanism unit 12 are separated, and FIG. 7C being a cross-sectional view of the state in which the discharge mechanism unit 11 and the pressure mechanism unit 12 are separated.

[0033] The structure of each mechanism (discharge mechanism 11, pressure mechanism 12) will be described in detail below with reference to the drawings.

[0034] <Discharge mechanism section> 8A and 8B are exploded views of the components of the discharge mechanism unit 11 shown in FIG. 7, in which FIG. 8A is a perspective view of each component constituting the discharge mechanism unit 11, FIG. 8B is a front view of each component constituting the discharge mechanism unit 11, and FIG. 8C is a cross-sectional view of each component constituting the discharge mechanism unit 11.

[0035] 1 to 8, the ejection mechanism 11 includes a barrel 11a, a nib 11b, and a seal 11c. The barrel 11a has a cylindrical portion 21 and a tapered portion 22 that tapers from one end of the cylindrical portion 21, with an opening 23 formed at the tip of the tapered portion 22. The nib 11b is housed in a tip-side space formed inside the barrel 11a, and has a tip portion (corresponding to the tip of the thin tube portion 31a described below) with an ink outlet hole (corresponding to the ink outlet hole 31c described below) protruding from the opening 23. The seal 11c is an O-ring that prevents leakage of sand ink contained in the ink reservoir 12a (leakage into the threaded portion between the cylindrical portion 21 and the ink reservoir 12a; see FIGS. 2, 3, 5, and 6).

[0036] Furthermore, in the discharge mechanism unit 11, a female screw 24 is formed on almost the entire inner wall of the cylindrical portion 21 (see FIGS. 7(c) and 8(c)), and further, a step portion 25 (the diameter of which decreases in three steps from the top) is formed inside the reduced diameter portion 22 along the tapered outer shape (see FIG. 8(c)). The first reduced diameter portion 25a has a female screw 26 formed on a part of its side wall, the second reduced diameter portion 25b has a first engagement portion 27 formed on the side wall of the second reduced diameter portion 25b for positioning the pen tip portion 11b, and the third reduced diameter portion 25c has a second engagement portion 28 formed on the side wall of the third reduced diameter portion 25c for positioning the pen tip portion 11b (see FIG. 8(c)).

[0037] The pen tip portion 11b also includes a valve body 31 having a long, thin, cylindrical capillary portion 31a that forms an ink flow path therein, and a disk-shaped valve portion 31b provided at one end of the capillary portion 31a to open and close the ink flow path from the ink containing tube 12a.

[0038] FIG. 9 is an enlarged view showing an example of the structure and shape of the valve body 31, in which (a) is a front view, (b) is a cross-sectional view seen from the front, (c) is a side view, (d) is a cross-sectional view seen from the side, (e) is a top view, (f) is a bottom view, and (g) and (h) are perspective views.

[0039] In the valve body 31 shown in Figure 9, an ink outlet hole 31c is formed at the other end side (tip of the valve body 31) of the thin tube portion 31a, which ejects sand ink flowing through the internal ink flow path, and further, multiple (two in this embodiment) ink inlet holes 31d are formed in the side wall of the thin tube portion 31a on the valve portion 31b side.

[0040] Furthermore, a metal pipe 31e is attached to the thin tube portion 31a of the valve body 31, extending from the ink outlet hole 31c at the tip through the ink flow path toward the ink inlet hole 31d so as to be in close contact with the inner wall of the thin tube portion 31a (see FIGS. 9(b) and 9(d)). This pipe 31e is attached to protect the thin tube portion 31a of the valve body 31 from the writing pressure (load) applied during writing, and extends, for example, from the ink outlet hole 31c at the tip, past the opening 23 of the barrel 11a, to a position inside the reduced diameter portion 22 (see FIGS. 2, 3, 5, 6, etc.). In this embodiment, in order to be able to eject sand with a particle diameter φ of 0.2 to 0.4 mm (large particle diameter sand), the inner diameter of the pipe 31e is set to, for example, 0.6 mm, which allows the sand to be ejected reliably without clogging. Although the present embodiment uses metal pipe 31e, materials other than metal may be used as long as they are strong enough to protect thin tube portion 31a from the pressure of writing. For example, if pipe 31e is made of the same material as thin tube portion 31a, thin tube portion 31a and pipe 31e can be molded integrally.

[0041] In this way, by employing pipe 31e strong enough to protect thin tube portion 31a from the writing pressure during writing, the ink flow path (inner diameter) inside thin tube portion 31a is stabilized without being crushed by the writing pressure, and large-sized sand can be reliably ejected without clogging. Furthermore, the structure in which high-viscosity sand ink is ejected from ink outlet hole 31c (only one place at the tip) formed in thin tube portion 31a allows for lines to be drawn without cracks, compared to conventional ink ejection mechanisms in which the pen tip is pressed axially to form a gap between the inner surface of the tip and the valve body, thereby ejecting high-viscosity ink from the outside of the pen tip.

[0042] 9, a groove 31f is formed on the outer periphery of the valve portion 31b of the valve body 31, into which an O-ring seal member 32 is fitted. By fitting the seal member 32 into this groove 31f, the valve body 31 is formed to prevent ink leakage. For example, when writing is not being performed (when the valve is closed), as shown in FIG. 6(a), the valve seat 25d formed on the bottom of the second reduced diameter portion 25b and the seal member 32 fitted into the valve portion 31b are in close contact, preventing sand ink from flowing from the space formed by the second reduced diameter portion 25b into the space formed by the third reduced diameter portion 25c.

[0043] That is, in the valve body 31 configured as described above, the valve portion 31b is seated on the valve seat 25d formed at the bottom of the second reduced diameter portion 25b when the valve is closed (see Figure 6(a)), and when the valve is open, a gap is formed between the valve portion 31b and the valve seat 25d as an ink flow path (see Figure 6(b)).

[0044] Furthermore, the pen tip portion 11b is equipped with a coil spring 33 and a spring receiver 34 (see Figures 8, 6, etc.). The coil spring 33 functions as an elastic body having a restoring force for returning the pen tip portion 11b (valve body 31 in the open state: see Figures 5 and 6(b)) tilted by writing pressure to its original position (direction), i.e., the direction of the central axis of the barrel 11a (see Figures 2, 3, and 6(a)). The spring receiver 34 has an annular outer periphery 34a that is in close contact with and engaged with the first engagement portion 27 formed on the side wall of the second reduced diameter portion 25b inside the reduced diameter portion 22 of the barrel 11a, and an annular groove 34b for supporting one end of the coil spring 33 is formed in the center of the plane formed by the outer periphery 34a.

[0045] 10 shows an example of the structure and shape of the spring receiver 34. In detail, (a) is a front view, (b) is a cross-sectional view seen from the front, (c) is a bottom view, and (d) and (e) are perspective views. One end of the coil spring 33 is supported by the groove 34b of the spring receiver 34 shown in FIG. 10, and the other end is supported by the spring receiver 31g, which is an annular groove formed in the valve portion 31b (the upper end portion shown in FIG. 9) of the valve body 31 (see FIG. 6, etc.). The action of this coil spring 33 allows the pen tip portion 11b (see FIG. 6(b)), which has been tilted by writing pressure, to return to its original position (direction), i.e., the direction of the central axis (axial direction) of the barrel 11a (see FIG. 6(a)).

[0046] As shown in Figure 10, the spring receiver 34 has a plurality of through holes 34c formed around the annular groove portion 34b on the plane formed by the outer peripheral portion 34a, and these through holes 34c allow the sand ink pushed out of the ink containing tube 12a by pressure to flow toward the valve body 31 (valve portion 31b).

[0047] Furthermore, the pen tip portion 11b is equipped with an annular sealing member 35 (see Figures 8 and 6, etc.). This sealing member 35 has a through-hole formed in the center so that it fits tightly around the entire outer periphery of the capillary tube portion 31a, and is attached by inserting the capillary tube portion 31a into this through-hole (see Figure 6, etc.). The outer periphery of the sealing member 35 is formed so that it fits tightly against the side wall of the third reduced diameter portion 25c (see Figure 6). This sealing member 35 prevents the sand ink from flowing out from anywhere other than the ink outlet hole 31c, i.e., prevents the sand ink from leaking out from the gap between the opening 23 formed at the tip of the reduced diameter portion 22 and the capillary tube portion 31a of the pen tip portion 11b.

[0048] In addition, the sealing member 35, together with the coil spring 33, also functions as an elastic body having a restoring force for returning the pen tip portion 11b (valve body 31 in the open state) that has been tilted due to writing pressure to its original position (direction), i.e., the central axis direction (axial direction) of the barrel 11a.

[0049] In this embodiment, the pen tip portion 11b and seal member 11c configured as described above are attached to predetermined positions within the barrel 11a to obtain the discharge mechanism portion 11. Specifically, with the thin tube portion 31a of the pen tip portion 11b protruding from the opening 23 of the barrel 11a, the seal member 35 of the pen tip portion 11b is engaged and fixed to the second engaging portion 28 formed on the third reduced diameter portion 25c, and the spring receiver 34 of the pen tip portion 11b is engaged and fixed to the first engaging portion 27 formed on the second reduced diameter portion 25b, thereby obtaining the discharge mechanism portion 11.

[0050] According to the discharge mechanism 11 of this embodiment, when the user starts writing, the valve element 31, which was initially held on the central axis, tilts against the restoring force of the coil spring 33 and the seal member 35 due to the writing pressure. This tilts the valve element 31, which is initially held on the central axis, and resists the restoring force of the coil spring 33 and the seal member 35. A gap forms between the valve element 31b and the valve seat 25d at the bottom of the second reduced-diameter portion 25b, opening the valve. Sand ink, pressurized by a constant force by the compression portion 12b (described later), flows out of the narrow tube portion 31a of the open nib portion 11b (valve element 31). When the user finishes writing, the restoring force of the coil spring 33 and the seal member 35 returns the valve element 31 to its original closed state, stopping the flow of sand ink from the nib portion 11b.

[0051] <Pressure mechanism> Next, the structure of the pressure mechanism 12 will be described in detail.

[0052] 11 and 12 are exploded views of the components of the pressure mechanism 12 shown in FIG. 7, where FIG. 11 is a perspective view of each component that constitutes the pressure mechanism 12, FIG. 12(a) is a front view of each component that constitutes the pressure mechanism 12, and FIG. 12(b) is a cross-sectional view of each component that constitutes the pressure mechanism 12.

[0053] 1 to 7, 11, and 12, the pressurizing mechanism 12 includes an ink containing tube 12a and a compression unit 12b. As shown in FIG. 2(c), the compression unit 12b is made up of a cylindrical rear end cap 41, a cylindrical spring receiver 42 having one end fixed to the center of the bottom of the rear end cap 41, a plunger 43 having a seal member 43a attached to an attachment portion 43b provided at the tip of a rod-shaped shaft portion 43c, and a coil spring 44 supported by the other end (tip) of the spring receiver 42 and the attachment portion 43b. The compression unit 12b applies a constant pressure to the sand ink contained in the ink containing tube 12a by the biasing force of the coil spring 44.

[0054] The length of the coil spring 44 before a load is applied is approximately the same as the length of the shaft portion 43c. That is, Fig. 2(c) shows the coil spring 44 in a state where it is deflected by a certain load (for example, a deflection of about 30 mm). The coil spring 44 used has an elastic force (resilience) sufficient to eject the sand ink, and the length can be changed appropriately depending on, for example, the viscosity of the sand ink.

[0055] 11 and 12, the ink containing tube 12a is cylindrical, for example, and slides back and forth along the inner surface of the rear end cap 41 while containing sand ink, and further, a male screw 12c is formed on part of the outer circumferential surface of the tip of the ink containing tube 12a, and is engaged with a female screw 26 formed on the side wall of the first reduced diameter portion 25a of the barrel 11a. By fastening the female screw 26 and the male screw 12c together, the ink containing tube 12a is fixed to the ejection mechanism 11 (see FIGS. 2, 3, 5, 6, etc.).

[0056] The rear end cap 41 of the compression portion 12b has a male screw 41a formed on part of the outer circumferential surface of the tip end portion, which screws into the female screw 24 formed on almost the entire inner wall of the cylindrical portion 21 of the barrel tube 11a.

[0057] The compression portion 12b is obtained by attaching the coil spring 44 so as to surround the shaft portion 43c of the plunger 43, and then inserting the shaft portion 43c of the plunger 43 from its rear end into the spring receiver 42 that is integrally fixed to the bottom of the rear end cap 41 (see Figure 2, etc.).

[0058] The pressurizing mechanism 12 is obtained by press-fitting the tip (sealing member 43a) of the plunger 43 of the compression section 12b into the rear end of the ink containing tube 12a (see FIGS. 2, 3, 7, etc.).

[0059] <Details of the overall structure of the writing instrument> Next, based on the structures of the discharge mechanism 11 and the pressure mechanism 12 described above, the overall configuration of the writing instrument 1 of this embodiment will be described in more detail with reference to the drawings.

[0060] The writing instrument 1 of this embodiment is obtained by integrating the above-described discharge mechanism 11 and pressure mechanism 12. Specifically, as shown in Fig. 2, first, the ink reservoir 12a is fixed to the discharge mechanism 11 by fastening the female screw 26 formed on the side wall of the first reduced diameter portion 25a of the barrel 11a (cylindrical portion 21) to the male screw 12c formed on the outer circumferential surface of the ink reservoir 12a, and in this state, sand ink is filled into the ink reservoir 12a. At this time, the sand ink flows through the through hole 34c formed in the spring receiver 34 of the nib portion 11b and reaches the top of the valve body 31.

[0061] Then, the tip (sealing member 43a) of the plunger 43 of the pressure mechanism 12 is pressed into the rear-end opening of the ink reservoir 12a until it abuts the sand ink. The male thread 41a on the outer periphery of the rear-end cap 41 is screwed into the female thread 24 on the inner wall of the barrel 11a (cylindrical portion 21). The rear-end cap 41 is then further screwed into the barrel 11a. The front and rear ends of the plunger 43 are in contact with the surface of the sand ink and the bottom of the rear-end cap 41, respectively. The rear-end cap 41 is screwed into the barrel 11a so that the initial deflection of the coil spring 44 is approximately 30 mm (assuming the length of the spring receiver 42 is approximately 30 mm). This brings the writing instrument 1 to its initial appearance (before ink is used) as shown in FIG. 2, and the writing instrument 1 is ready to write with the sand ink pressurized by the compression portion 12b with a certain force.

[0062] Next, when a normal writing operation is initiated with the writing instrument 1 tilted at an angle, as shown in FIGS. 5 and 6(b), the pressure of the writing instrument causes the valve element 31 (thin tube portion 31a), which was initially held on the central axis, to tilt against the restoring force of the coil spring 33 and the sealing member 35. Then, sand ink, pressurized with a constant force by the compression portion 12b, flows through the gap between the valve portion 31b of the tilted valve element 31 and the valve seat 25d, and through the space formed by the third reduced diameter portion 25c, into the thin tube portion 31a from the ink inlet hole 31d of the valve element 31, and then out through the ink outlet hole 31c. Because the sand ink is constantly pressurized with a constant force by the compression portion 12b, this embodiment allows a constant amount of sand ink to be continuously and stably ejected.

[0063] In other words, in the writing instrument 1 of this embodiment, when writing with the pen tilted at an angle, the valve body 31 (thin tube portion 31a) tilts relative to the central axis (moves radially relative to the central axis) against the restoring force of the coil spring 33 and the sealing member 35, thereby opening the valve, and ejecting the sand ink that has flowed in from the tip of the valve body 31.

[0064] After that, when the normal writing operation is completed, the restoring force of the coil spring 33 and the sealing member 35 returns the valve body 31 to its original closed state, and the outflow of sand ink from the ink outlet hole 31c of the thin tube portion 31a stops (see Figure 6(a)). For example, when using the high-viscosity sand ink mentioned above (sand particle size φ of 0.2 to 0.4 mm, viscosity without sand of approximately 50,000 mPa·S), the coil spring 33 requires a load of about 1 N to close the valve from the open state during writing.

[0065] 5, as normal writing continues, the amount of sand ink in the ink reservoir 12a gradually decreases, and the plunger 43 is also pushed downward by the elastic force (restoring force) of the coil spring 44. As the plunger 43 descends, its rear end gradually moves away from the bottom surface of the rear end cap 41. For example, when the deflection of the coil spring 44 reaches about 10 mm (when the plunger 43 moves forward about 20 mm), the restoring force of the coil spring 44 weakens, and the compression section 12b can no longer apply a constant pressure to the sand ink, resulting in a decrease in the amount of sand ink discharged.

[0066] Therefore, in this embodiment, normal writing is temporarily terminated before the sand ink can no longer be pressurized with a constant force (before the coil spring 44 has deflected approximately 10 mm), and the rear end cap 41 is screwed further into the barrel 11a. At this time, the rear end cap 41 is screwed further into the barrel 11a until the rear end of the plunger 43 abuts the bottom surface of the rear end cap 41, that is, until the coil spring 44 has deflected approximately 30 mm from the initial state. This allows the writing instrument 1 to eject a constant amount of sand ink by pressurizing the sand ink with a constant force, just as it did initially (before ink was used). Therefore, when normal writing is resumed, stable writing becomes possible again.

[0067] By repeatedly screwing in the rear end cap 41 in this manner before the deflection of the coil spring 44 reaches approximately 10 mm, stable writing becomes possible until the sand ink finally runs out, as shown in FIG. 3, for example.

[0068] In other words, in the writing instrument 1 of this embodiment, the structure allows repeated re-pressurization by screwing in the rear end cap 41, so the sand ink can always be pressurized with a constant force, making it possible to eject a constant amount of sand ink until it runs out.

[0069] <Suitable materials for writing implements> Although not particularly limited, the writing instrument 1 of this embodiment is preferably made of a synthetic resin material. For example, general-purpose plastics such as polypropylene or engineering plastics such as polycarbonate are used for parts that do not require significant deformation or sealing (hermetic seal) during assembly or use, such as the barrel 11a, ink reservoir 12a, cap 13, valve element 31, spring receiver 34, rear end cap 41, spring receiver 42, and barrel 43c. The seal members 32, 35, and 43a are preferably made of rubber materials with rubber elasticity, such as nitrile rubber, butadiene rubber, or silicone rubber. Furthermore, the coil springs 33 and 44 may be made of metals such as stainless steel.

[0070] <Sand Ink Composition> Next, a description will be given of a suitable ink composition for the writing instrument 1 of this embodiment. For example, a synthetic resin emulsion containing silica sand is preferred as the sand ink used in the writing instrument 1 of this embodiment. Specifically, a high-viscosity ink having a viscosity of 30 (Pa·s / 25°C) and a composition of 20% by mass of acrylic synthetic resin emulsion, 40% by mass of aggregate (silica sand No. 6 and No. 7), 13% by mass of extender pigment, 12% by mass of color pigment, 1.5% by mass of dispersant, 1.5% by mass of thickener, and the remainder being purified water, is used. Another example is an ink having a viscosity of 48 (Pa·s / 25°C) and a composition of 16% by mass of vinyl acetate synthetic resin emulsion, 40% by mass of aggregate (silica sand No. 6 and No. 7), 20% by mass of extender pigment, 10% by mass of color pigment, 0.2% by mass of stabilizer, 0.5% by mass of thickener, and the remainder being purified water.

[0071] Although the ink used in the writing instrument 1 of this embodiment is the sand ink described above as an example, the present invention is not limited to this, and the writing instrument 1 can be used with any ink that is highly viscous and contains coarse particles (particles other than sand). Furthermore, the writing instrument 1 of this embodiment can also be used with, for example, a particle-free high-viscosity ink, and does not preclude the use of particle-free high-viscosity ink. In other words, the writing instrument 1 of this embodiment is constantly pressurized with a constant force by the pressure mechanism 12, and therefore can continuously and stably eject a constant amount of high-viscosity ink (regardless of whether particles are present) through normal writing operations. <Effects> As described above, the writing instrument 1 of this embodiment includes a barrel 11a and a nib portion 11b housed inside the barrel 11a and projecting its tip from the tip opening of the barrel 11a, and is equipped with an ejection mechanism 11 that ejects ink from the tip. The writing instrument 1 also includes a pressure mechanism 12 that includes an ink reservoir 12a attached to the ejection mechanism 11 and a compression portion 12b that applies a constant pressure to the ink contained in the ink reservoir 12a. The nib portion 11b functions as a valve that opens and closes the ink flow path. The nib portion 11b tilts relative to the central axis of the barrel 11a due to the writing pressure applied during the writing action, opening the valve and ejecting ink that has flowed into the ink flow path from the tip.

[0072] This allows high-viscosity ink containing coarse particles to be continuously and stably ejected with the same writing action as with a normal writing implement. [Explanation of symbols]

[0073] 1 writing implements 11 Discharge mechanism section 11a Shaft cylinder 11b Pen tip 11c Sealing material 12 Pressure mechanism 12a Ink containing tube 12b Compression section 12c male screw 13 Cap 21 Cylindrical part 22 Reduced diameter part 23 Opening 24 female screw 25 Step section 25a First reduced diameter portion 25b Second reduced diameter portion 25c Third narrowing section 25d valve seat 26 female screw 27 First engagement portion 28 Second engagement portion 31 Valve body 31a Thin tube part 31b Valve part 31c Ink outlet hole 31d Ink inlet 31e pipe 31f Groove 31g spring holder 32 Sealing material 33 coil spring 34 Spring holder 34a outer periphery 34b Groove 34c through hole 35 Sealing material 41 Rear end cap 41a Male screw 42 Spring holder 43 Plunger 43a Sealing member 43b Mounting part 43c Shaft 44 coil spring

Claims

1. an ejection mechanism having a barrel and a pen tip portion housed inside the barrel and having a tip portion protruding from a tip opening of the barrel, the ejection mechanism ejecting ink from the tip portion; a pressure mechanism unit having an ink reservoir tube attached to the ejection mechanism unit and a compression unit that applies a constant pressure to the ink contained in the ink reservoir tube; Equipped with The pen tip functions as a valve that opens and closes the ink flow path, and is tilted relative to the central axis of the barrel by the writing pressure during writing, thereby opening the valve and ejecting ink that has flowed into the ink flow path from the tip. A writing instrument characterized by:

2. the pen tip portion is provided with a valve body having a cylindrical, long, thin capillary portion that forms an ink flow path therein, and a disc-shaped valve portion that is provided on one end of the capillary portion to open and close the ink flow path; When the valve is opened, ink pressurized with a constant force by the compression section is discharged from an ink outlet hole formed in the tip section, which is the other end side of the thin tube section.

2. The writing instrument according to claim 1.

3. The pen tip portion includes an elastic body having a restoring force for returning the pen tip portion, which has been tilted by writing pressure, to its original position, and when the writing operation is completed, the restoring force of the elastic body causes the valve to be in a closed state, and the closing of the valve stops the ejection of ink.

3. The writing instrument according to claim 2.

4. The barrel has a cylindrical portion and a tapered portion tapering from one end of the cylindrical portion, a male screw formed on the outer peripheral surface of the cylindrical compression portion and a female screw formed on the inner wall of the cylindrical portion are screwed together, and the compression portion is further screwed into the barrel by further screwing, thereby pressurizing the ink contained in the ink containing tube with a constant force; 2. The writing instrument according to claim 1.

Images