WO2025053261A1 - Writing instrument - Google Patents

Abstract

This writing instrument comprises: a barrel (11) that has an internal space serving as an ink reservoir part for containing ink and is deformable through a side surface thereof being pressed; a writing tip end (14) formed as a brush including bundled fibers; a front barrel (12) into which the writing tip end is inserted and that is attached to the tip end of the barrel; a cylindrical brush tip holding member (20) that is contained inside the front barrel and holds the rear end of the writing tip in a tip end direction; and a valve mechanism that is contained in a tip end part of the barrel, is interposed between the ink reservoir part and the brush tip holding member, and opens as the side surface of the barrel is pressed. The writing instrument allows the liquid discharge amount to be controlled by varying pressing force that is applied to the barrel.

Description

Writing implements

This disclosure relates to a writing instrument that has a valve mechanism inside the barrel and supplies ink by pressing the barrel.

　Conventionally, so-called valve-type felt-tip pens, which have a valve mechanism inside the barrel, have been known to open the valve by pressing the pen tip with writing pressure (JP Patent Publication No. 2014-87947) or by knocking the rear end (JP Patent Publication No. 9-271710). However, these methods have problems such as not being able to use soft materials such as brush tips as the pen tip, and it being difficult to control the amount of liquid dispensed.

In particular, the technology described in Patent Document 1 makes it possible to prevent the direct current phenomenon in which a large amount of ink unintentionally flows out, a phenomenon known as "dripping," which causes ink or coating liquid to spurt out. However, in a felt-tip pen that uses an elastic blow container for the barrel and has a mechanism for opening the valve by pressing the side of the container to allow the liquid to flow out, liquid sometimes spurts out when the valve is opened. Therefore, the objective of the embodiment of the present disclosure is to prevent sudden liquid leakage (the phenomenon known as "dripping") in a writing instrument with a valve mechanism that opens when the barrel is pressed, and to make it easier to control the amount of liquid discharged by varying the strength of pressure.

The aspects of this disclosure are as follows:

<Aspect 1>
The writing instrument of the first aspect includes a barrel having an internal space that serves as an ink storage section for storing ink, and a barrel that is deformable when a side surface of the barrel is pressed;
A writing tip formed as a brush tip made of bundled fibers;
A tip barrel into which the writing tip is inserted and which is attached to the tip of the barrel;
A cylindrical brush tip holding member that is housed inside the tip barrel and holds the rear end of the writing tip in a tip direction;
a valve mechanism that is accommodated in the tip portion of the barrel, interposed between the ink container and the brush tip holding member, and opens when a side surface of the barrel is pressed;
In addition to providing
The amount of liquid discharged can be controlled by varying the strength of pressure applied to the barrel.

<Aspect 2>
The writing instrument of the second aspect has, in addition to the configuration of the first aspect, a partition wall that divides the inside of the brush tip holding member into two in the front-rear direction and has an insertion hole formed in the axis center;
a cylindrical intermediate core that is inserted into the insertion hole to communicate between the valve mechanism and the writing tip and is made of a porous material;
Equipped with.

In the writing instrument of embodiment 2, the ink flows through the intermediate tip. When the ink flows through the intermediate tip, flow resistance is generated, which prevents the ink from dripping.

<Aspect 3>
In addition to the configuration of embodiment 2, the writing instrument of embodiment 3 has a porosity of the intermediate core of 50% or more and less than 65%. If the porosity is less than 50%, the ink may clog, making it difficult to use as a writing instrument. On the other hand, if the porosity is 65% or more, no flow resistance is generated, making it difficult to control the amount of liquid discharged. Therefore, it is preferable that the porosity of the intermediate core is 50% or more and less than 65%.

<Aspect 4>
In addition to the configuration of the writing instrument of the fourth aspect, the axial length of the insertion hole is 0.5 mm or more and less than 10 mm. If the axial length is less than 0.5 mm, it becomes difficult to hold the intermediate core. On the other hand, if the axial length is 10 mm or more, the retention length becomes too long, which affects the porosity of the intermediate core and makes it difficult to control the amount of liquid discharged. Therefore, it is preferable that the axial length of the insertion hole is 0.5 mm or more and less than 10 mm.

In the writing instruments of aspects 3 and 4, flow resistance can be efficiently controlled.

<Aspect 5>
The writing instrument of Aspect 4 has, in addition to the configuration of Aspect 1, the valve mechanism:
a valve retaining member fixed to the barrel;
a valve inserted into the valve holding member and movable in a forward and backward direction;
a spring retaining member that is inserted into the rear end of the valve retaining member, the bottom plate constituting the tip edge of the spring retaining member being abutted against and fixed to the tip edge of the valve retaining member, and the rear end portion of the spring retaining member being inserted into the tip portion of the valve;
a spring interposed between the spring retaining member and the valve, and constantly biasing the valve backward with respect to the valve retaining member;
having
When the valve is biased backward, the gap between the spring retainer and the valve is closed, thereby preventing the flow of ink.
When the valve compresses the spring due to the pressure on the side of the barrel, the gap between the spring retainer and the valve is opened.
The ink passes through a first inlet hole that is opened to the ink storage section by the valve holding member,
The liquid passes through a liquid passage formed by a gap between a first liquid passage surface which is an inner surface of the spring retaining member and a second liquid passage surface which is an outer surface of the valve, a gap between a liquid passage edge which is a tip of the valve and the spring retaining member, and a gap between a third liquid passage surface which is an inner surface of the valve and the spring retaining member,
It passes through the internal space of the spring holding member to reach the writing tip.

In the writing instrument of aspect 5, the ink flows through a narrow passageway. When the ink flows through the intermediate tip, flow resistance is generated, preventing the ink from dripping.

<Aspect 6>
A writing instrument according to a sixth aspect has the structure of the fifth aspect, and further comprises an elastic portion at a rear end of the valve that is elastically deformable in response to pressure fluctuations inside the ink storage portion;
External air that enters from the writing tip as writing progresses through the internal space of the spring retaining member and the air vent that is the internal space of the valve, and reaches the ink storage section through an air gap created by the elastic deformation of the elastic section.

In aspect 6, by generating flow resistance of the ink in a narrow liquid passage and by differentiating the ink flow path from the air replacement flow path, it is possible to prevent so-called dripping while not impeding ink ejection. In addition, because the valve is a movable part, the structure is such that even if the ink dries and solidifies inside the valve, the ink flow path can be re-established by reopening the valve.

According to the aspects of the present disclosure, a writing instrument with a valve mechanism that opens when the barrel is pressed can prevent sudden liquid outflow (so-called dripping) and make it easier to control the amount of liquid dispensed by varying the strength of pressure.

FIG. 1 is a front view of a writing instrument according to an embodiment of the present disclosure. FIG. 2 is a front view showing the writing instrument of FIG. 1 with the cap removed. FIG. 2 is a parts assembly diagram of the writing instrument of FIG. 1 . FIG. 2 is a front perspective view of the intermediate core and the brush tip holding member. FIG. 2 is a rear perspective view of the intermediate core and the brush tip holding member. FIG. 2 is a front cross-sectional view of a relay core and a brush tip holding member. FIG. 2 is a front perspective view of a brush tip holding member with a relay core attached. FIG. 2 is a rear perspective view of the brush tip holding member with the intermediate core attached. FIG. 2 is a front view of the brush tip holding member with the intermediate core attached. FIG. 2 is a plan view of the brush tip holding member with the intermediate core attached. FIG. 2 is a bottom view of the brush tip holding member with the intermediate core attached. This is a cross-sectional view taken along the line VV in FIG. 5C. FIG. FIG. FIG. FIG. FIG. 4 is a front perspective view of a spring retaining member; FIG. 4 is a rear perspective view of the spring retaining member; FIG. FIG. FIG. 4 is a bottom view of the spring retaining member. 8C is a cross-sectional view taken along line XIII-XIII of FIG. 8C. FIG. 4 is a front perspective view of the valve retaining member. FIG. 4 is a rear perspective view of the valve retaining member. FIG. FIG. FIG. FIG. 4 is a bottom view of the valve holding member. IXa-IXa cross-sectional view of FIG. 9C. IXb-IXb cross-sectional view of FIG. 9D. FIG. FIG. FIG. FIG. FIG. FIG. This is a cross-sectional view of Figure 10C taken along the line Xa-Xa. This is a cross-sectional view taken along the line Xb-Xb of Figure 10D. This is a cross-sectional view taken along the line XIa-XIa in FIG. This is a cross-sectional view of Figure 11A along the line XIb-XIb. 11B shows an enlarged view of the valve mechanism in the state shown in FIG. 11A. 1 is a front view of a writing instrument with the cap removed, with the side surface of the barrel pressed. FIG. This is a cross-sectional view taken along line XIVa-XIVa of Figure 13. This is a cross-sectional view of Figure 14A along the line XIVb-XIVb. 14B shows an enlarged view of the valve mechanism in the state shown in FIG. 14A. FIG. 16 is a top perspective view of the valve mechanism of FIG. This is a cross-sectional view taken along the line XVIIa-XVIIa in FIG. 2. This is a cross-sectional view of Figure 17A along the line XVIIb-XVIIb. 17B shows an enlarged view of the valve mechanism alone in the state shown in FIG. 17A. FIG. 20 is a top perspective view of the valve mechanism of FIG. 18. The experimental method used to measure the flow resistance due to the material of the intermediate core is shown diagrammatically.

Embodiments of the present disclosure are described below. Note that reference numerals commonly used in multiple drawings indicate common members or parts even if there is no specific explanation for each drawing. Furthermore, the dimensions and ratios of each part shown in the drawings do not necessarily match the dimensions and ratios of the actual product. Furthermore, the dimensional relationships and ratios may differ between the drawings.

In addition, in this disclosure, the side of the writing instrument where the writing tip is located is referred to as the "tip", the direction toward the tip is referred to as the "forward" side, the opposite side is referred to as the "rear end", and the direction toward the rear end is referred to as the "publication".

FIG. 1 is a front view showing the appearance of a writing instrument 10 of the present disclosure. A generally cylindrical tip barrel 12 of generally the same diameter is attached to the tip of a generally cylindrical barrel 11, and a generally cylindrical cap 13 of generally the same diameter is further attached to the tip of the tip barrel 12. FIG. 2 is a front view showing the state in which the cap 13 has been removed from the state shown in FIG. 1. The tip barrel 12 is composed of a generally cylindrical covering portion 12A that covers the tip of the barrel 11, an outer peripheral engaging portion 12B located on the tip side of the covering portion 12A, which is slightly reduced in diameter and has a protrusion formed on the outer periphery for engaging with the cap 13, and a tapered portion 12C at the tip of the covering portion 12A that is tapered toward the front and has an open tip. A writing tip 14 formed as a brush tip 14A made of fine bundled fibers protrudes from the opening of the tapered portion 12C.

FIG. 3 is a perspective view of the parts assembly diagram of the writing instrument in FIG. 1. The barrel 11 is composed of a hollow, roughly cylindrical large diameter section 11A and a small diameter section 11B that is tapered at its tip. The internal space of the barrel 11 serves as an ink storage section 11C (see FIG. 11A) that stores ink. The barrel 11 is made of a relatively soft and flexible synthetic resin (such as polypropylene resin or low-density polyethylene resin), and can be deformed by pressing the sides as shown in FIG. 13.

The writing tip 14 is composed of a tip 14A formed by bundling fine fibers into a tapered shape, and a flange 14B with an expanded diameter at the rear end. As described above, the tip barrel 12 is composed of the covering portion 12A, the outer peripheral locking portion 12B, and the tapered portion 12C. The writing tip 14 is inserted into the inside of the tip barrel 12. As shown in Figures 11A and 11B, the internal space of the tapered portion 12C of the tip barrel 12 forms a front insertion hole 12D with a small inner diameter located on the tip side, and a rear insertion hole 12E with a larger inner diameter behind it. The covering portion 12A of the tip barrel 12 is pressed in so as to cover the small diameter portion 11B of the barrel, thereby attaching the tip barrel 12 to the tip of the barrel 11. Furthermore, when the cap 13 is attached, the tapered portion 12C is covered, and the inner peripheral engaging portion 13A (see FIG. 11A), which is a protrusion formed on the inner surface of the cap 13, engages with the outer peripheral engaging portion 12B.

The brush tip holding member 20 is formed as a roughly cylindrical member. The brush tip holding member 20 is housed inside the tip barrel 12 with the writing tip 14 inserted, and holds the rear end of the writing tip 14 in the tip direction. A cylindrical porous intermediate core 30 is inserted into the brush tip holding member 20. The intermediate core 30 is a member that connects the valve mechanism 40 and the writing tip 14.

The valve mechanism 40 is housed in the tip of the barrel 11, interposed between the ink storage section 11C (see FIG. 11A) and the brush tip holding member 20, and opens when the side of the barrel 11 is pressed (see FIG. 13). The valve mechanism 40 has a valve holding member 50 that is generally cylindrical and fixed to the barrel, a valve 60 that is inserted into the valve holding member 50 and can move in the front-rear direction, and a spring holding member 41 that is inserted inside the rear end of the valve holding member 50.

Examples of the porous material of the relay core 30 include porous bodies (sintered cores) and foams made by sintering synthetic resin powders such as polyacetal resin, polyethylene resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, polyolefin resin, polyvinyl resin, polycarbonate resin, polyether resin, polyphenylene resin, fluorine resin, and styrene resin.

4A to 4C are a front perspective view (Fig. 1A), a rear perspective view (Fig. 1B), and a front cross-sectional view (Fig. 1C) of the intermediate core 30 and the brush tip holding member 20. The brush tip holding member 20 has a substantially cylindrical side wall 21, a partition wall 22 that divides the interior in the front-rear direction, and an insertion hole 23 formed at the axis of the partition wall 22. A ring-shaped protrusion 24 is formed on the rear edge of the insertion hole 23. The inner surface of the tip side of the side wall 21 is slightly enlarged in diameter in a ring shape, and this part forms the holding step 25. The intermediate core 30 is formed of a porous body such as a fiber bundle, and is composed of a substantially cylindrical conductive part 31 in the rear part, and a puncture part 32 formed with a slightly smaller diameter in the front part. The conductive part 31 is the part that is inserted into the insertion hole of the brush tip holding member 20. The puncture portion 32 is the portion that is punctured by the rear end of the writing tip 14. Here, the axial length α of the insertion hole 23 is 0.5 mm or more and less than 10 mm.

5A to 5F are a front perspective view (FIG. 1A), a rear perspective view (FIG. 1B), a front view (FIG. 1C), a plan view (FIG. 1D), a bottom view (FIG. 1E) and a V-V cross-sectional view of FIG. 5C of the brush tip holding member 20 to which the intermediate core 30 is attached. When the intermediate core 30 is inserted into the insertion hole 23 (see FIG. 4C) of the brush tip holding member 20, the rear end of the conductive portion 31 protrudes rearward from the rear end edge of the side wall 21, and the tip of the puncture portion 32 protrudes forward from the tip edge of the side wall 21. In other words, the intermediate core 30 is held by the brush tip holding member 20 in a state where it is inserted into the insertion hole 23. Here, it is desirable that the diameter of the conductive portion 31 is formed to be about 0.1 mm larger than the diameter of the insertion hole 23, so that it is slightly pressed into the insertion hole 23. In this case, it is desirable that the ratio of the axial length α (see FIG. 4C) of the insertion hole 23 to the length β (see FIG. 4C) of the relay core be 10% or more and less than 50%.

FIGS. 6A to 6C are a front view (FIG. 6A), a plan view (FIG. 6B), and a bottom view (FIG. 6C) of the valve mechanism 40. As described above, the valve mechanism has a valve holding member 50, a valve 60, and a spring holding member 41. A pair of first inlet holes 55 are formed in the rear portion of the valve holding member 50 (FIG. 6B), through which the inserted valve 60 can be seen. The leading edge of the spring holding member 41 abuts against the leading edge of the valve holding member 50 (FIG. 6A). Also, FIG. 7 is a parts assembly diagram of the valve mechanism 40. A spring 42 is interposed between the valve 60 inserted into the valve holding member 50 and the spring holding member 41, and the valve 60 is always biased backward relative to the valve holding member 50.

FIGS. 8A to 8F are a front perspective view (FIG. 8A), a rear perspective view (FIG. 8B), a front view (FIG. 8C), a plan view (FIG. 8D), a bottom view (FIG. 8E), and a cross-sectional view taken along line XIII-XIII of FIG. 8C (FIG. 8F). The spring retaining member 41 comprises a flange-shaped bottom plate 41A, a front tubular portion 41B having a smaller diameter at its rear, a middle tubular portion 41C having a smaller diameter at its rear, and a rear tubular portion 41D having a smaller diameter at its rear. The step between the front tubular portion 41B and the middle tubular portion 41C is a liquid passage step 41E, and the step between the middle tubular portion 41C and the rear tubular portion 41D is a retention step 41F. The internal space of the spring retaining member 41 is a flow hole 41G whose inner diameter gradually decreases toward the rear in accordance with the size of the outer diameter.

9A to 9H are a front perspective view (Fig. 9A), a rear perspective view (Fig. 9B), a front view (Fig. 9C), a side view (Fig. 9D), a plan view (Fig. 9E), a bottom view (Fig. 9F), a IXa-IXa cross-sectional view of Fig. 9C (Fig. 9G), and an IXb-IXb cross-sectional view of Fig. 9D (Fig. 9H). The valve holding member 50 has a flange-shaped leading edge 51, a smaller diameter storage tube portion 52 at the rear of the valve holding member 50, a smaller diameter liquid passage tube portion 53 at the rear of the valve holding member 50, and a smaller diameter annular portion 54 at the rear of the valve holding member 50. A pair of first inlet holes 55 are formed on the side of the liquid passage tube portion 53. The valve holding member 50 is formed hollow, and its internal space becomes a storage hole 56 in which the valve 60 is stored. The inner surface of the storage tube portion 52 becomes a first liquid passage surface 57. A step is formed at the leading edge of the first liquid passage surface 57, which serves as the blocking step 58. The bottom plate 41A of the spring retaining member 41 (FIGS. 8A to 8F) described above abuts against and is fixed to the leading edge of the valve retaining member 50.

Figures 10A to 10H are a front perspective view (Figure 10A), a rear perspective view (Figure 10B), a front view (Figure 10C), a side view (Figure 10D), a plan view (Figure 10E), a bottom view (Figure 10F), a Xa-Xa cross-sectional view of Figure 10C (Figure 10G), and an Xb-Xb cross-sectional view of Figure 10D (Figure 10H). Valve 60 is equipped with a cylindrical liquid passage tube 63 located at the front, an intermediate band 64 that expands slightly in diameter behind it, a blocking slope 65 that tapers in diameter behind it, and a cylindrical vent tube 66 that is smaller in diameter than the liquid passage tube 63 behind it. The internal space of the liquid passage tube 63 is a second circulation hole 69A, and the internal space of the vent tube 66 is an air hole 69B. Furthermore, the outer peripheral surface of the fluid passage tube 63 is the second fluid passage surface 68A, the tip edge of the fluid passage tube 63 is the fluid passage edge 68B, and the inner peripheral surface of the fluid passage tube 63 is the third fluid passage surface 68C. The intermediate tube portion 41C and the rear tube portion 41D that constitute the rear end portion of the spring retaining member 41 (FIGS. 8A to 8F) are inserted into the tip portion of the valve 60.

The valve 60 is formed by two-color molding of a rigid portion 61 made of a synthetic resin with a relatively high rigidity, and an elastic portion 62 located at the rear end and made of a synthetic resin with a higher elasticity. The elastic portion 62 is composed of a band-shaped portion 62A that covers the portion slightly forward from the rear end in a band shape, an annular portion 62B that covers the rear end in a ring shape, a pair of connecting portions 62C that connect the band-shaped portion 62A and the annular portion 62B at the side, and a diaphragm 62D that is recessed forward from the annular portion 62B. The outer peripheral surface near the rear end of the ventilation tube 66 is a covered portion 67B where the portion that comes into contact with the band-shaped portion 62A, the annular portion 62B, and the connecting portion 62C is covered by the elastic portion 62. The portion of the rigid portion 61 that is surrounded by the elastic portion 62 is an exposed portion 67A.

FIG. 11A is a cross-sectional view taken along line XIa-XIa in FIG. 1, and is a cross-sectional side view of the writing instrument 10. Also, FIG. 11B is a cross-sectional view taken along line XIb-XIb in FIG. 11A, and is a cross-sectional front view of the writing instrument 10. The assembly of the writing instrument 1 will be explained with reference to the previous figures.

First, the writing tip 14 is inserted into the front barrel 12. At this time, the brush tip 14A (see Fig. 3) of the writing tip 14 is inserted into the front insertion hole 12D (Figs. 11A and 11B) of the front barrel 12. Then, the flange 14B (Fig. 3) of the writing tip 14 abuts against the step between the front insertion hole 12D and the rear insertion hole 12E of the front barrel 12 (Figs. 11A and 11B).

Next, the brush tip holding member 20 with the intermediate core 30 inserted therethrough is inserted into the tip barrel 12. At this time, the brush tip holding member 20 is housed in the rear insertion hole 12E of the tip barrel 12. The tip of the side wall 21 (Fig. 4C) of the brush tip holding member 20 then abuts against the step (Figs. 11A, 11B) between the front insertion hole 12D and the rear insertion hole 12E of the tip barrel 12, while at the same time the holding step 25 (Fig. 4C) on the tip edge of the side wall 21 holds the flange 14B (Fig. 3) of the writing tip 14.

Meanwhile, the valve 60 (Fig. 7) is inserted from the tip of the valve holding member 50 (Fig. 7) and the blocking slope 65 (Figs. 10D, 10G, 10H) is brought into contact with the blocking step 58 (Figs. 9G, 9H). At this time, the vent tube 66 (Fig. 10C) of the valve 60 is located inside the fluid passage tube portion 53 (Figs. 9G, 9H) of the valve holding member 50, and the fluid passage tube 63 is located in the accommodation hole 56 (Figs. 9G, 9H) of the valve holding member 50.

Then, the spring retaining member 41 (Fig. 7), with the spring 42 (Fig. 7) fitted to the rear tubular portion 41D (Figs. 8C, 8F), is inserted into the tip of the valve retaining member 50 (Fig. 7). At this time, the bottom plate 41A (Figs. 8C, 8F) of the valve retaining member 50 abuts against the tip edge 51 (Figs. 9C, 9D, 9G, 9H) of the valve retaining member 50. In this state, the spring 42 (Fig. 7) is supported between the retaining step 41F (Figs. 8C, 8F) of the spring retaining member 41 and the step between the second flow hole 69A and the air hole 69B of the valve 60 (Figs. 10G, 10H), thereby constantly biasing the valve 60 backward.

The valve mechanism 40 (Fig. 6A) is formed by attaching the valve 60, spring 42, and spring holding member 41 to the valve holding member 50. This valve mechanism 40 is inserted into the barrel 11 (Figs. 11A, 11B) with the ink storage section 11C filled with ink 11D. At this time, the storage tube section 52 (Figs. 10G, 10H) of the valve holding member 50 is located inside the small diameter section 11B (Fig. 3) of the barrel 11, and the liquid passage tube section 53 (Figs. 10G, 10H) is located at the tip of the ink storage section 11C (Figs. 11A, 11B). Furthermore, the tip edge 51 (Figs. 9G, 9H) of the valve holding member 50 abuts against the tip edge of the small diameter section 11B (Fig. 3) of the barrel 11 (Figs. 11A, 11B).

Then, when the covering portion 12A (Fig. 3) of the front barrel 12 is made to cover the small diameter portion 11B (Fig. 3) of the barrel 11, the bottom plate 41A of the spring holding member 41 presses against the rear edge of the brush tip holding member 20 (Figs. 11A, 11B). Finally, the tapered portion 12C of the front barrel 12 is inserted from the rear end of the cap 13, and the inner peripheral locking portion (Figs. 11A, 11B) is engaged with the outer peripheral locking portion 12B (Fig. 3), completing the writing instrument 10 shown in Figs. 1, 11A, and 11B.

FIG. 12 shows an enlarged view of only the valve mechanism 40 in the state shown in FIG. 11. In this state, the valve 60 is biased backward by the spring 42, causing the blocking slope 65 of the valve 60 to come into close contact with the blocking step 58 of the valve holding member 50. As a result, ink 11D that has entered the inside of the valve mechanism 40 from the first inlet hole 55 cannot flow between the valve holding member 50 and the valve 60, and ink 11D is not supplied to the writing tip 14. In other words, when the valve 60 is biased backward, the gap between the valve holding member 50 and the valve 60 is closed, preventing the flow of ink 11D.

FIG. 13 is a front view of the writing instrument 10 with the cap 13 removed, with the side of the barrel 11 pressed. FIG. 14A is a cross-sectional view taken along line XIVa-XIVa of FIG. 13, and FIG. 14B is a cross-sectional view taken along line XIVb-XIVb of FIG. 14A. As shown in these figures, when the side of the barrel 11 is pressed, the pressure inside the ink storage section 11C increases. This increased pressure presses the valve 60 forward against the biasing force of the spring 42. FIG. 15 is an enlarged view of the valve mechanism 40 in this state. Pressing the valve 60 forward separates the blocking step 58 of the valve retaining member 50 and the blocking slope 65 of the valve 60, allowing ink 11D to flow between them.

In other words, as the side of the barrel 11 is pressed, the valve 60 compresses the spring 42, opening the gap between the valve holding member 50 and the valve 60. At this time, the ink 11D flows into the valve mechanism 40 through the first inlet hole 55 that the valve holding member 50 opens to the ink storage section 11C.

As shown by the arrows in FIG. 15, the ink 11D flows between the blocking step 58 and the blocking slope 65, and then through the gap between the first liquid passing surface 57, which is the inner surface of the valve holding member 50, and the second liquid passing surface 68A, which is the outer surface of the valve 60, the gap between the liquid passing edge 68B, which is the tip of the valve 60, and the spring holding member 41, and the gap between the third liquid passing surface 68C, which is the inner surface of the valve 60, and the spring holding member 41, and then through the flow hole 41G, which is the internal space of the spring holding member 41, to reach the writing tip 14. At this time, the diaphragm 62D of the valve 60 remains recessed toward the tip, as shown in FIG. 15 and FIG. 16, which shows the state of FIG. 15 in a perspective view.

As mentioned above, even if the internal pressure of the ink storage section 11C increases, the ink 11D experiences flow resistance as it passes through the narrow liquid passage 70. In addition, the ink that reaches the flow hole 41G of the spring retaining member 41 must pass through the porous relay core 30, and so experiences flow resistance there as well. This prevents the ink 11D from dripping from the writing tip 14.

When the pressure applied to the side of the barrel 11 is released, it returns to the state shown in FIG. 2. FIG. 17A shows the state at this time in the XVIIa-XVIIa cross section, and FIG. 17B shows the XVIIb-XVIIb cross section of FIG. 17A. When the pressure on the barrel 11 is released, the internal pressure of the ink storage section 11C drops rapidly, and air flows in from the outside due to the negative pressure by the amount of ink 11D consumed. FIG. 18 shows an enlarged view of only the valve mechanism 40 in this state. FIG. 19 shows a perspective view of this state. As shown by the arrow in FIG. 18, the diaphragm 62D of the valve 60 protrudes backward due to the pressure of the air that has passed through the circulation hole 41G and the ventilation hole 69B from the writing tip 14. At this time, air flows into the ink storage section 11C through the ventilation gap 80 generated between the rigid part 61 and the elastic part 62.

In other words, the valve 60 has an elastic portion 62 at its rear end that can elastically deform due to pressure fluctuations inside the ink storage section 11C. Then, the outside air that enters from the writing tip 14 during writing passes through the circulation hole 41G, which is the internal space of the spring holding member 41, and the ventilation hole 69B, which is the internal space of the valve 60, and reaches the ink storage section 11C through the ventilation gap 80 created by the elastic deformation of the elastic portion 62.

As described above, in the writing instrument 10 of this embodiment, the flow path for the ink 11D and the flow path for air replacement can be separated, so smooth air replacement can be achieved even if the flow path for the ink 11D is narrow. In addition, it is easy to adjust the ejection condition of the ink 11D by changing the strength of the pressure on the side of the barrel 11.

Next, we verified the appropriate porosity for the material of the relay core 30. Specifically, we verified whether a porous body with the properties shown in Table 1 below would cause flow resistance to the liquid. Note that the porosity shown in Table 1 below is a numerical value that represents the ratio of voids to the cross-sectional area of the porous body.

As for the above-mentioned Examples 1 to 4 and Comparative Example, as shown in the schematic diagram in FIG. 20, the rear end of the barrel 11 of the writing instrument 10 shown in FIG. 11A was opened and a pressure gauge 160 and syringe 100 were attached to observe whether flow resistance occurred. As the intermediate core 30, a material having the porosity shown in Examples 1 to 4 or Comparative Example in Table 1 was used. Then, the syringe 100 was pressed in the direction of the arrow in the figure so that the ink flow rate was 10 ml/min, and the pressure gauge 160 was used to confirm whether flow resistance occurred.

As a result, the relay core 30 of the comparative example with a porosity of 67% did not generate sufficient flow resistance (pressure loss), and the pressure loss at that time was 0.1 kPa/s or less. In contrast, the relay core 30 with a porosity of 54% to 62% as in Examples 1 to 4 provided appropriate flow resistance, and the generated pressure loss was 0.5 kPa/s or more. From the above, it is inferred that the porosity of the porous body suitable for this embodiment is 50% or more and less than 65%, and that the necessary flow resistance is 0.5 kPa/s or more.

In addition, with the writing instrument disclosed herein, it is possible to adjust the flow rate by adjusting the porosity of the intermediate core and the length at which flow resistance occurs.

In light of the above, preferred embodiments of the writing instrument disclosed herein are as follows:

The writing instrument 10 of the first embodiment includes a barrel 11 whose internal space is an ink storage section 11C that stores ink 11D and which is deformable when a side surface of the barrel is pressed;
A writing tip 14 formed as a brush tip made of bundled fibers;
a tip barrel 12 into which the writing tip 14 is inserted and which is attached to the tip of the barrel 11;
A cylindrical brush tip holding member 20 that is housed inside the tip barrel 12 and holds the rear end of the writing tip 14 in a tip direction;
A valve mechanism 40 that is accommodated in the tip portion of the barrel 11 and is interposed between the ink storage portion 11C and the brush tip holding member 20, and that opens when the side surface of the barrel 11 is pressed;
In addition to providing
The amount of liquid discharged can be controlled by varying the strength of pressure applied to the barrel 11 .

The writing instrument 10 of the second embodiment has, in addition to the configuration of the first embodiment, a partition wall 22 that divides the inside of the brush tip holding member 20 into two in the front-rear direction and has an insertion hole 23 formed in the axis center;
a cylindrical intermediate core 30 that is inserted into the insertion hole 23 to connect the valve mechanism 40 and the writing tip 14 and is made of a porous material;
Equipped with.

The third embodiment of the writing instrument 10 has the same configuration as the second embodiment, but the porosity of the intermediate core 30 is 50% or more and less than 65%.

The fourth embodiment of the writing instrument 10 has the same configuration as the third embodiment, but the axial length of the insertion hole 23 is 0.5 mm or more and less than 10 mm.

The writing instrument 10 of the fifth embodiment has the same configuration as the first embodiment, and further comprises:
A valve holding member 50 fixed to the barrel 11;
A valve 60 that is inserted into the valve holding member 50 and is movable in the forward and backward directions;
a spring holding member 41 that is inserted into the rear end of the valve holding member 50, with a bottom plate 41A constituting a leading edge thereof abutting and fixed to the leading edge of the valve holding member 50, and a rear end portion thereof being inserted into the leading end portion of the valve 60;
a spring 42 interposed between the spring holding member 41 and the valve 60 and always biasing the valve 60 backward with respect to the valve holding member 50;
having
When the valve 60 is biased backward, the gap between the spring holding member 41 and the valve 60 is closed, thereby preventing the flow of the ink 11D.
When the valve 60 compresses the spring 42 in response to the pressure on the side of the barrel 11, the gap between the spring retaining member 41 and the valve 60 is opened.
The ink 11D passes through a first inlet 55 that opens to the ink storage portion 11C of the valve holding member 50,
The liquid flows through a liquid passage 70 including a gap between a first liquid passage surface 57, which is the inner surface of the spring retaining member 41, and a second liquid passage surface 68A, which is the outer surface of the valve 60, a gap between a liquid passage edge 68B, which is the tip of the valve 60, and the spring retaining member 41, and a gap between a third liquid passage surface 68C, which is the inner surface of the valve 60, and the spring retaining member 41.
The spring passes through the internal space of the spring holding member 41 and reaches the writing tip 14 .

The writing instrument 10 of the sixth embodiment has the same configuration as the fifth embodiment, and further has an elastic portion 62 at the rear end of the valve 60 that is elastically deformable in response to pressure fluctuations inside the ink storage portion 11C,
External air that enters from the writing tip 14 when writing passes through the internal space of the spring retaining member 41 and the internal space of the valve 60, which is the ventilation hole 69B, and reaches the ink storage section 11C through the ventilation gap 80 created by the elastic deformation of the elastic section 62.

The present invention can be used in writing instruments that have a valve mechanism inside the barrel and supply ink by pressing the barrel.

Claims (6)

an ink container having an internal space for storing ink, the ink container being deformable when a side surface of the ink container is pressed;
A writing tip formed as a brush tip made of bundled fibers;
A tip barrel into which the writing tip is inserted and which is attached to the tip of the barrel;
A cylindrical brush tip holding member that is housed inside the tip barrel and holds the rear end of the writing tip in a tip direction;
a valve mechanism that is accommodated in the tip portion of the barrel, interposed between the ink container and the brush tip holding member, and opens when a side surface of the barrel is pressed;
In addition to providing
A writing implement that allows the amount of liquid dispensed to be controlled by varying the strength of pressure applied to the barrel. A partition wall that divides the inside of the brush tip holding member into two in the front-rear direction and has an insertion hole formed at the axis center;
a cylindrical intermediate core that is inserted into the insertion hole to communicate between the valve mechanism and the writing tip and is made of a porous material;
The writing instrument of claim 1 , comprising: The writing instrument according to claim 2, wherein the porosity of the intermediate core is 50% or more and less than 65%. The writing instrument according to claim 3, wherein the axial length of the insertion hole is 0.5 mm or more and less than 10 mm. The valve mechanism includes:
a valve retaining member fixed to the barrel;
a valve inserted into the valve holding member and movable in a forward and backward direction;
a spring retaining member that is inserted into the rear end of the valve retaining member, the bottom plate constituting the tip edge of the spring retaining member being abutted against and fixed to the tip edge of the valve retaining member, and the rear end portion of the spring retaining member being inserted into the tip portion of the valve;
a spring interposed between the spring retaining member and the valve, and constantly biasing the valve backward with respect to the valve retaining member;
having
When the valve is biased backward, the gap between the spring retainer and the valve is closed, thereby preventing the flow of ink.
When the valve compresses the spring due to the pressure on the side of the barrel, the gap between the spring retainer and the valve is opened.
The ink passes through a first inlet hole that is opened to the ink storage section by the valve holding member,
The liquid passes through a liquid passage formed by a gap between a first liquid passage surface which is an inner surface of the spring retaining member and a second liquid passage surface which is an outer surface of the valve, a gap between a liquid passage edge which is a tip of the valve and the spring retaining member, and a gap between a third liquid passage surface which is an inner surface of the valve and the spring retaining member,
The writing implement according to claim 1 , wherein the spring reaches the writing tip through an internal space of the spring retaining member. the valve has a rear end provided with an elastic portion that is elastically deformable in response to pressure fluctuations within the ink storage portion;
6. The writing instrument according to claim 5, wherein the outside air that enters from the writing tip during writing passes through an air vent which is the internal space of the spring retaining member and the internal space of the valve, and reaches the ink storage section through an air vent gap created by the elastic deformation of the elastic section.