Writing implement

Abstract

This writing implement comprises: a shaft cylinder (11) in which an internal space is an ink storage part for storing ink, and which can be deformed by a side surface thereof being pressed; a writing tip (14) formed as a brush tip obtained by bundling fibers; a tip shaft (12) which is attached to a tip of the shaft cylinder while the writing tip is inserted; a valve mechanism which is stored in a tip part of the shaft cylinder and opens in conjunction with pressing of the side surface of the shaft cylinder; a valve insertion member (41) having a bottom plate which is positioned at a tip edge of the valve mechanism and has a valve insertion hole formed in the shaft center, and a cylindrical part which is inserted into the tip side of the valve mechanism and in which a rear storage part is formed in the internal space; and a flow path resistance valve (30) which is stored in the rear storage part and has a columnar part in which the tip surface is in contact with the rear end surface of the bottom plate of the valve insertion member, and an insertion part which protrudes from the tip surface of the columnar part and is inserted into the valve insertion hole. A liquid passing groove that is recessed to the rear is formed in a portion of the tip surface of the columnar part of the flow path resistance valve.

Description

writing implements

[0001] The present disclosure relates to a writing instrument that has a valve mechanism inside a barrel and supplies ink by pressing the barrel.

[0002] Conventionally, so-called valve-type sign pens equipped with a valve mechanism inside the barrel have been known to open the valve by pressing the pen tip with writing pressure (Japanese Patent Application Laid-Open No. 2014-87947) or by knocking the rear end (Japanese Patent Application Laid-Open No. 9-271710). However, these methods have had issues such as not being able to use soft materials such as brush tips as the pen tip, and difficulty in controlling the amount of liquid dispensed. A writing instrument has also been disclosed in which the internal valve mechanism is closed by attaching a cap (Japanese Patent Application Laid-Open No. 2021-115710).

[0003] In particular, the technology described in JP 2014-87947 A 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 is the blowing out of ink or coating liquid. However, in a felt-tip pen that uses a highly elastic blow-type 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, the liquid sometimes spurts out when the valve opens. Therefore, an aspect of the present disclosure aims to prevent sudden liquid spillage (so-called dripping) in a writing instrument with a valve that opens by pressing the body, and to make it easier to control the amount of liquid ejected by varying the strength of the pressure.

[0004] The aspects of the present disclosure are as follows.

[0005] <Aspect 1> A writing implement of Aspect 1 comprises a barrel whose internal space is an ink storage section that stores ink and is deformable when its side surfaces are pressed; a writing tip formed as a brush tip made of bundled fibers; a front barrel into which the writing tip is inserted and which is attached to the front end of the barrel; a valve mechanism that is housed in the front end portion of the barrel and opens when the side surfaces of the barrel are pressed; a valve insertion member that has: a bottom plate that is located on the front edge of the valve mechanism and has a valve insertion hole formed at its axis, and a tubular portion that is inserted into the interior of the front end side of the valve mechanism and has a rear storage section formed in its internal space; and a flow path resistance valve that is housed in the rear storage section and has a columnar portion whose front end surface contacts the rear end surface of the bottom plate of the valve insertion member, and an insertion portion that protrudes from the front end surface of the columnar portion and is loosely fitted into the valve insertion hole, The valve retaining member has a valve that is inserted into the valve retaining member and is movable in the forward and backward directions, and a spring that is inserted inside the valve and interposed between the valve and the rear end face of the flow path resistance valve, and that constantly urges the valve rearward relative to the valve retaining member, and a liquid passage groove that is recessed rearward is formed in part of the tip end face of the cylindrical part of the flow path resistance valve.

[0006] In the writing instrument of aspect 1, ink is supplied from the barrel to the writing tip via the valve mechanism, but the flow path of the ink is restricted by the flow path resistance valve, so even if you try to supply ink by pressing the barrel, the outflow of ink is restricted, preventing so-called dripping.

[0007] <Aspect 2> A writing instrument in Aspect 2, in addition to the configuration of Aspect 1, further comprises: a front barrel insert that is inserted into the front end of the front barrel with the writing tip inserted therethrough, with the front end edge exposed from the front end of the front barrel; a brush tip holding member that has the insertion portion of the flow path resistance valve inserted into it and held at its axis, and that is inserted into the front barrel insert to hold the writing tip while an abutment plate formed at the rear end abuts against the rear end of the front barrel insert; and a cap that covers the front end of the front barrel and has multiple ribs provided therein that have stepped rear ends, and when the cap is attached to the front barrel, the stepped ribs press the front end of the front barrel insert rearward.

[0008] In the writing instrument of Aspect 2, when the cap is attached, the tip of the front insert abuts against a rib inside the cap and is pressed and moves rearward. The brush tip holding member located at the rear end of the front insert then moves rearward along with the movement of the front insert, and the inserted flow resistance valve presses the valve spring rearward, restricting the opening of the valve. In other words, the valve does not open when the cap is attached. Therefore, ink leakage is restricted even when the barrel is pressed with the cap attached.

[0009] A writing instrument with a valve that opens when the body 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 the pressure.

[0010] 6B is a front view of a writing instrument according to an embodiment of the present disclosure. FIG. 1 is a perspective view of the writing instrument of FIG. 1. FIG. 2 is a perspective view showing the writing instrument with the cap removed. FIG. 1 is a front view showing the writing instrument with the cap removed. FIG. 1 is a component assembly diagram of the writing instrument of FIG. 1. FIG. 6C is a front perspective view of the tip barrel with the writing tip attached. FIG. 6D is a front view of the tip barrel with the writing tip attached. FIG. 6E is a cross-sectional view taken along VI-VI of FIG. 6B. FIG. 6F is a component assembly diagram of the valve mechanism. FIG. 6G is a front perspective view of the valve retaining member. FIG. 6H is a rear perspective view of the valve retaining member. FIG. 6I is a plan view of the valve retaining member. FIG. 6J is a bottom view of the valve retaining member. FIG. 8I is a cross-sectional view taken along VIII-VIII of FIG. 8D. FIG. 8I is a front perspective view of the valve retaining member. FIG. 8J is a rear perspective view of the valve retaining member. FIG. 8I is a front view of the valve retaining member. FIG. 8I is a side view of the valve retaining member. FIG. 8I is a plan view of the valve retaining member. FIG. 8I is a bottom view of the valve retaining member. FIG. 9C is a cross-sectional view taken along IXa-IXa of FIG. 9C. FIG. 9D is a cross-sectional view taken along IXb-IXb of FIG. 9D. FIG. 9I is a front perspective view of the valve. FIG. 9I is a rear perspective view of the valve. FIG. 9I is a front view of the valve. 11C 。 12C 。 13C 。 14C 。 14A 。 14B 。 15C 。 16C 。 17C 。 18C 。 19C 。 20C 。 21C 。 22C 。 23C 。 24C 。 25C 。 26C 。 27C 。 28C 。 29C 。 30C 。 31C 。 32C 。 33C 。 34C 。 35C 。 36C 。 37C 。 38C 。 39C 。 40C 。 41C 。 42C 。 43C 。 44C 。 45C 。 46C 。 47C 。 48C 。 49C 。 50C 。 51C 。 52C 。 53C 。 54C 。 55C 。 56C 。 57C 。 58C 。 59C 。 60C 。 61C 。 62C 。 63C 。 64C 。 65C 。 66C 。 67C 。 68C 。 69C 。 70C 。 71C 。 72C 。 73C 。 74C 。 75C 。 76C 。 77C 。 78C 。 79C 。 80C 。 81C 。 82C 。 83C 。 84C 。 85C 。 86C 。 87C 。 88C 。 89C 。 90C 。 91C 。 92C 。 93C 。 17 shows an enlarged cross section of the tip portion in a state where the pressure is released from the state shown in FIG. 16.

[0011] An embodiment of the present disclosure will be described below. Note that reference numerals commonly used in multiple drawings indicate common components or parts even if no specific explanation is given for each drawing. Furthermore, the dimensions and proportions of each part shown in the drawings do not necessarily correspond to the dimensions and proportions of the actual product. Furthermore, the dimensional relationships and proportions between the drawings may differ.

[0012] Furthermore, 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," the opposite side is referred to as the "rear end," and the direction toward the rear end is referred to as the "open end."

[0013] Figures 1 and 2 are a front view and a perspective view, respectively, showing the appearance of a writing instrument 10 of the present disclosure. A generally cylindrical front 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 front barrel 12. Figures 3 and 4 are a perspective view and a front view, respectively, showing the state from the state shown in Figures 1 and 2 with the cap 13 removed. The front 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 ridge 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 reduces in diameter toward the front and opens to the tip. From the opening at the tip of the tapered portion 12C, the writing tip 14 formed as a brush tip 14A made of bundled fine fibers and the tip edge of the tip barrel insert 15 that is inserted into the tip of the tip barrel 12 with the writing tip 14 inserted are exposed.

[0014] Figure 5 is a perspective view of the parts assembly diagram of the writing instrument of Figure 1. The barrel 11 is composed of a hollow, approximately cylindrical large-diameter section 11A and a small-diameter section 11B whose diameter is reduced toward the tip. The internal space of the barrel 11 forms an ink storage section 11C (see Figure 13) 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 is deformable as shown in Figure 13 when the side surfaces are pressed.

[0015] The writing tip 14 is composed of a tapered brush tip 14A made of a bundle of fine fibers and a flange 14B with an expanded diameter at the rear end. As described above, the front barrel 12 is composed of a covering portion 12A, an outer peripheral locking portion 12B, and a tapered portion 12C. The front barrel insert 15 is composed of a cylindrical front portion 15A and a rear portion 15B located behind it and with an expanded diameter. The O-ring 16 is made of silicone rubber and has an annular shape. The writing tip 14 is inserted into the interior of the front barrel 12. The covering portion 12A of the front barrel 12 is press-fitted to cover the small-diameter portion 11B of the barrel, thereby attaching the front barrel 12 to the tip of the barrel 11. When the cap 13 is attached, the tapered portion 12C is covered, and the inner peripheral locking portion 13A (see FIG. 14A), a ridge formed on the inner surface of the cap 13, locks with the outer peripheral locking portion 12B. 14A, multiple ribs 13C are provided inside cap 13, which covers the tip of front barrel 12. Ribs 13C reach from the tip to the middle of the inner circumferential surface of cap 13, and their rear ends form steps 13B.

[0016] The brush tip holding member 20 is formed as a substantially cylindrical member with a flange formed on the rear edge. The detailed structure thereof will be described later.

[0017] The valve mechanism 40 is housed in the tip portion of the barrel 11, interposed between the ink storage section 11C (see Figure 13) and the brush tip holding member 20 (see Figure 5), and is a member that opens when the side surface of the barrel 11 is pressed (see Figure 16). The valve mechanism 40 has a substantially cylindrical valve holding member 50 that is fixed to the barrel, a valve 60 (see Figure 7) that is inserted into the valve holding member 50 and is movable in the front-rear direction, a valve insertion member 41 that is inserted inside the rear end of the valve holding member 50, and a flow path resistance valve 30 whose tip portion protrudes from the valve insertion member 41.

[0018] Figures 6A to 6C are a front perspective view (Figure 6A), a front view (Figure 6B), and a VI-VI cross-sectional view of the tip barrel 12 with the writing tip 14 attached. As shown in Figure 6C, the internal space of the tapered portion 12C of the tip barrel 12 is divided into 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 located behind it. As shown in Figure 6C, an O-ring 16 is inserted into the step between the front insertion hole 12D and the rear insertion hole 12E of the tip barrel 12. Then, the tip barrel insert 15 is inserted from the rear end of the tip barrel 12 so that the front portion 15A is located in the front insertion hole 12D and the rear portion 15B is located in the rear insertion hole 12E. Next, writing tip 14 is inserted from the rear end of front barrel 12 by inserting brush tip 14A through front portion 15A of front barrel insert 15 and bending flange 14B to the right at the step between front portion 15A and rear portion 15B. Finally, brush tip holding member 20 is inserted from the rear end of front barrel 12 by positioning insertion portion 21 (FIG. 12C) in rear portion 15B of front barrel insert 15 and abutting plate 22 (FIG. 12C) against the rear edge of rear portion 15B. In this state, as shown in FIGS. 6A and 6B , the tip portion of writing tip 14 and the tip portion of front barrel insert 15 protrude from the opening at the tip of front barrel 12.

[0019] 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 flow path resistance valve 30 inserted into the valve insertion member 41, and the valve 60 is constantly biased backward relative to the valve holding member 50.

[0020] 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 (FIG. 8F) of the valve inserting member 41 taken along line VIII-VIII of FIG. 8D. The valve inserting member 41 comprises a flange-shaped bottom plate 41A and a cylindrical portion 41B having a smaller diameter at the rear of the bottom plate 41A. The bottom plate 41A is located at the leading edge of the valve mechanism 40, and a valve insertion hole 41C is formed in its axis. The cylindrical portion 41B is inserted into the leading end of the valve mechanism 40, and a rear accommodation portion 41D is formed in the internal space.

[0021] 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 (FIG. 9G) of FIG. 9C, and a IXb-IXb cross-sectional view (FIG. 9H) of FIG. 9D of the valve retaining member 50. The valve retaining member 50 includes a flange-shaped leading edge 51, a smaller-diameter accommodating tubular portion 52 at its rear, a smaller-diameter fluid-passing tubular portion 53 at its rear, and a smaller-diameter annular portion 54 at its rear. A pair of first inlet holes 55 are formed in the side of the fluid-passing tubular portion 53. The valve retaining member 50 is hollow, and its internal space forms an accommodating hole 56 in which a valve 60 is accommodated. A step is formed on the inner surface between the accommodating tubular portion 52 and the fluid-passing tubular portion 53, forming a blocking step 58. The bottom plate 41A of the valve inserting member 41 (FIGS. 8A to 8F) is fixed in contact with the leading edge of the valve holding member 50. The cylindrical portion 41B constituting the rear end portion of the valve inserting member 41 (FIGS. 8A to 8F) is inserted into the leading end portion of the valve holding member 50.

[0022] 10A to 10H are a front perspective view (FIG. 10A), a rear perspective view (FIG. 10B), a front view (FIG. 10C), a side view (FIG. 10D), a plan view (FIG. 10E), a bottom view (FIG. 10F), a cross-sectional view Xa-Xa of FIG. 10C (FIG. 10G), and a cross-sectional view Xb-Xb of FIG. 10D (FIG. 10H) of the valve 60. The valve 60 includes 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 and located behind it. The internal space of the liquid passage tube 63 is a second flow hole 69A, and the internal space of the vent tube 66 is a vent hole 69B.

[0023] The valve 60 is formed by two-color molding with a rigid portion 61 made of a relatively rigid synthetic resin and an elastic portion 62 located at the rear end and made of a more elastic synthetic resin. The elastic portion 62 is composed of a band-shaped portion 62A that covers the portion slightly forward of the rear end, 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 sides, and a diaphragm 62D that is recessed forward from the annular portion 62B. The outer peripheral surface of the vent tube 66 near the rear end, which abuts the band-shaped portion 62A, the annular portion 62B, and the connecting portion 62C, is covered by the elastic portion 62 to form a covered portion 67B. The portion of the rigid portion 61 surrounded by the elastic portion 62 is an exposed portion 67A.

[0024] 11A to 11G are a front perspective view (FIG. 11A), a rear perspective view (FIG. 11B), a front view (FIG. 11C), a side view (FIG. 11D), a plan view (FIG. 11E), a bottom view (FIG. 11F), and a cross-sectional view (FIG. 11G) taken along line XI-XI of FIG. 11C of the flow path resistance valve 30. The flow path resistance valve 30 comprises a substantially cylindrical columnar portion 31, a substantially cylindrical insertion portion 32 protruding from the center of the tip surface of the columnar portion 31, and a substantially cylindrical protruding portion 33 whose diameter increases toward the tip side of the insertion portion 32. A pair of fluid passage grooves 34 are formed in a portion of the tip surface of the columnar portion 31, recessed rearward with the insertion portion 32 sandwiched therebetween. The portion from the tip of the protruding portion 33 to partway along the insertion portion 32 is divided into two by a notch 35. The formation of this notch 35 allows the two halves of the protruding portion 33 and the insertion portion 32 to bend axially relative to each other. The columnar portion 31 is accommodated in the rear accommodation portion 41D (FIG. 8F) of the valve insertion member 41, and its tip surface contacts the rear end surface of the bottom plate (FIG. 8F) of the valve insertion member 41. The insertion portion 32 is inserted into the valve insertion hole 41C (FIGS. 8A, 8B, and 8F) of the valve insertion member 41.

[0025] Figures 12A to 12E show a front perspective view (Figure 12A), a rear perspective view (Figure 12B), a front view (Figure 12C), a bottom view (Figure 12D), and a cross-sectional view (Figure 12E) of the brush tip holding member 20 taken along the line XII-XII of Figure 12C. The brush tip holding member 20 has a generally cylindrical insertion portion 21 and an enlarged abutment plate 22 formed at its rear end. A through-hole 23 is formed at the axis of the abutment plate 22, through which the insertion portion 32 (Figures 11A to 11C) of the flow path resistance valve 30 passes. Multiple peripheral grooves 23A are formed radially around the through-hole 23 (Figure 12D). The internal space of the insertion portion 21 forms a front accommodation portion 24 that accommodates and holds the protrusion 33 of the flow path resistance valve 30.

[0026] Figure 13 is a cross-sectional view taken along line XIII-XIII in Figure 4, showing a side cross-sectional view of the writing instrument 10. Figure 14A is a cross-sectional view taken along line XIVa-XIVa in Figure 1, showing a side cross-sectional view of the writing instrument 10. Figure 14B is a cross-sectional view taken along line XIVb-XIVb in Figure 14A, showing a front cross-sectional view of the writing instrument. Assembly of the writing instrument 10 will be described with reference to the previous figures.

[0027] First, O-ring 16 is inserted into tip barrel 12, then tip barrel insert 15 is inserted, and then writing tip 14 is inserted. At this time, tip 14A of writing tip 14 and front portion 15A of tip barrel insert 15 (see FIG. 5) are inserted into front insertion hole 12D (FIG. 6C) of tip barrel 12. Then, flange 14B (FIG. 3) of writing tip 14 abuts against a step (FIG. 6C) formed inside rear portion 15B of tip barrel insert 15.

[0028] Next, brush tip holding member 20 is inserted into tip barrel 12. At this time, brush tip holding member 20 is housed in rear insertion hole 12E of tip barrel 12, while insertion portion 21 (FIGS. 12A, 12C) is inserted into rear portion 15B of tip barrel insert 15 (FIG. 6C). In addition, abutment plate 22 (FIGS. 12B, 12C) formed at the rear end of brush tip holding member 20 abuts against the rear end of tip barrel insert 15 (FIG. 6C). In this state, the leading edge of brush tip holding member 20 presses forward against flange 14B (FIG. 5) of writing tip 14 and holds it there (FIG. 6C).

[0029] Meanwhile, the valve 60 (FIG. 7) is inserted from the tip of the valve holding member 50 (FIG. 7) so that the blocking slope 65 (FIGS. 10D, 10G, 10H) abuts against 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.

[0030] Then, the spring 42 (FIG. 7) is inserted into the second flow hole 69A of the valve 60. The insertion portion 32 (FIGS. 11A to 11D) of the flow path resistance valve 30 is inserted from the rear into the valve insertion hole 41C (FIGS. 8A and 8D) of the valve inserting member 41, with the protruding portion 33 penetrating forward. In this state, the flow path resistance valve 30 is inserted into the valve holding member 50 from the tip end, and the tubular portion 41B of the valve inserting member 41 is press-fitted into the valve holding member 50 from the tip end. At this time, the bottom plate 41A (FIGS. 8C and 8F) of the valve inserting member 41 abuts against the tip edge 51 (FIGS. 9C, 9D, 9G, and 9H) of the valve holding member 50. In this state, the spring 42 (FIG. 7) is supported between the cylindrical portion 31 (FIGS. 11A to 11D) of the flow path resistance valve 30 and the step (FIGS. 10G and 10H) between the second flow hole 69A and the air vent hole 69B of the valve 60, thereby constantly biasing the valve 60 backward.

[0031] The valve mechanism 40 is formed by attaching the valve 60, spring 42, and valve insertion member 41, through which the flow path resistance valve 30 is inserted, to the valve holding member 50. This valve mechanism 40 is inserted into the barrel 11 (FIG. 13) with the ink storage section 11C filled with ink 11D. At this time, the storage tube portion 52 (FIGS. 10G and 10H) of the valve holding member 50 is positioned inside the small diameter portion 11B (FIG. 3) of the barrel 11, and the liquid passage tube portion 53 (FIGS. 10G and 10H) is positioned at the tip of the ink storage section 11C (FIG. 13). Furthermore, the tip edge 51 (FIGS. 9G and 9H) of the valve holding member 50 abuts against the tip edge of the small diameter portion 11B (FIG. 5) of the barrel 11 (FIG. 13).

[0032] Then, the covering portion 12A (FIG. 5) of the tip barrel 12 covers the small diameter portion 11B (FIG. 5) of the barrel 11. At the same time, the protruding portion 33 (FIGS. 11A to 11D) of the flow path resistance valve 30 bends axially and passes through the through hole 23 (FIG. 12B) of the brush tip holding member 20. When the protruding portion 33 completely passes through the through hole 23, the axial bending is released and the protruding portion 33 returns to its original state shown in FIG. 11A. In this state, the step between the protruding portion 33 and the insertion portion 32 engages with the edge of the through hole 23, preventing the protruding portion 33 from slipping out rearward. In this state, the writing instrument 10 shown in FIG. 13 is completed.

[0033] When the tapered portion 12C of the front barrel 12 of the writing instrument 10 in the state shown in FIG. 13 is inserted from the rear end of the cap 13 and the inner peripheral locking portion (FIG. 13) is engaged with the outer peripheral locking portion 12B (FIG. 3), the writing instrument is in the state shown in FIGS. 1 and 3. A side cross-sectional view of this state is shown in FIG. 14A, and a front cross-sectional view is shown in FIG. 14B. In this state, the tip of the front barrel insert 15 protruding from the tip of the front barrel 12 abuts against the step at the rear end of the rib 13C inside the cap 13 and is pressed rearward. Accordingly, the flow path resistance valve 30 is also pressed rearward, compressing the spring 42 and pressing the valve 60 rearward. In other words, with the cap 13 attached to the front barrel 12, the step of the rib 13C presses the tip of the front barrel insert 15 rearward. In this state, forward movement of the valve 60 is prevented, and the blocking slope 65 of the valve 60 remains in close contact with the blocking step 58 of the valve holding member 50. As a result, with the cap 13 attached, ink 11D will not spurt out from the writing tip 14 even if sudden pressure is applied, such as when the barrel 11 is stepped on.

[0034] Figure 15 is an enlarged view of the tip portion in Figure 13. 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.

[0035] Figure 16 is a front view of the writing instrument 10 with the cap 13 removed, with the side of the barrel 11 pressed. Figure 17 is an enlarged view of the tip portion of Figure 16. When the side of the barrel 11 is pressed as shown in Figure 16, the pressure inside the ink storage compartment 11C increases. This increased pressure pushes the valve 60 forward, against the biasing force of the spring 42, as shown in Figure 17. Figure 15 is an enlarged view of the valve mechanism 40 in this state. When the valve 60 is pressed forward, the blocking step 58 of the valve holding member 50 and the blocking slope 65 of the valve 60 separate, allowing ink 11D to flow between them.

[0036] As described above, the ink 11D that can now flow between the valve holding member 50 and the valve 60 passes between the inner circumferential surface of the rear accommodation portion 41D (FIG. 8F) and the cylindrical portion 31 (FIG. 11G) of the flow path resistance valve 30. Furthermore, the ink 11D flows between the tip surface of the cylindrical portion 31 and the rear end surface of the bottom plate 41A (FIG. 8F) of the valve insertion member 41 via the liquid passage groove 34 (FIG. 11G) and passes through the peripheral groove 23A (FIG. 12D) to reach the writing tip 14. In other words, even if the pressure inside the ink accommodation portion 11C increases, the ink 11D faces flow resistance due to the narrow gap of the liquid passage groove 34 located between the tip surface of the cylindrical portion 31 and the rear end surface of the bottom plate 41A of the valve insertion member 41. This prevents the ink 11D from dripping from the writing tip 14.

[0037] When the pressure applied to the side of the barrel 11 is released, it returns to the state shown in Figure 4. Figure 18 shows this state in cross section taken along line XVIII-XVIII. When the pressure on the barrel 11 is released, the internal pressure of the ink containing section 11C drops rapidly, and the negative pressure causes air to flow into the valve 60 from the outside in an amount equal to the amount of ink 11D consumed. This air pressure causes the diaphragm 62D of the valve 60 to protrude rearward. At this time, air flows into the ink containing section 11C through the ventilation gap 80 created between the rigid portion 61 and the elastic portion 62.

[0038] The present invention can be used in a writing instrument that has a valve mechanism inside the barrel and supplies ink by pressing the barrel.

Claims

1. A pen comprising: a barrel having an internal space which serves as an ink storage section for storing ink and which can be deformed when the side surface 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 end of the barrel; a valve mechanism housed in the end portion of the barrel and which opens when the side surface of the barrel is pressed; a valve insertion member having: a bottom plate located on the end edge of the valve mechanism and having a valve insertion hole formed at its axis, and a tubular portion inserted into the inside of the end side of the valve mechanism and having a rear storage section formed in its internal space; and a flow path resistance valve housed in the rear storage section and having a cylindrical portion whose tip surface contacts the rear end surface of the bottom plate of the valve insertion member, and an insertion portion protruding from the tip surface of the cylindrical portion and which can be inserted into the valve insertion hole, a spring that is inserted into the valve and interposed between the valve and a rear end surface of the flow resistance valve, and that constantly urges the valve rearward relative to the valve retaining member, wherein a liquid passage groove that is recessed rearward is formed in part of the tip surface of the cylindrical portion of the flow resistance valve.

2. A writing instrument as described in claim 1, further comprising: a tip insert that is inserted into the tip of the tip barrel with the writing tip inserted therethrough, with the tip edge exposed from the tip of the tip barrel; a brush tip holding member that is inserted into the tip barrel insert and holds the writing tip while the insertion portion of the flow path resistance valve is inserted and held at the axis, and an abutment plate formed at the rear end is abutted against the rear end of the tip barrel insert; and a cap that covers the tip of the tip barrel and has multiple ribs provided inside which have stepped rear ends, and when the cap is attached to the tip barrel, the stepped ribs press the tip of the tip barrel insert rearward.

Images