Toothbrush

Abstract

[Problem] To provide a toothbrush with improved operability in the oral cavity through reduction of collision with the inner wall of the oral cavity caused when the toothbrush is inserted deep into the oral cavity. [Solution] A toothbrush 1 according to the present invention includes: a head portion 2 in which a plurality of brush bristle bundles 3 are each implanted at a right angle with respect to an implantation surface 20; a neck portion 5 connected to the head portion 2; and a grip portion 7 connected to the neck portion 2. The head portion 2 is composed of a base end side portion 21 extending in a longitudinal direction from a tip end of the neck portion 5, and a tip end side portion 23 extending in a longitudinal direction from a tip end of the base end side portion 21 via a step. The tip end side portion 23 is inclined in a bristle tip direction in which the brush bristle bundles 3 extend.

Description

toothbrush

[0001] The present invention relates to a toothbrush that is easy to operate.

[0002] In recent years, toothbrushes have been proposed that have a thinner head portion to make it easier to reach the back of the oral cavity and improve maneuverability within the oral cavity (see, for example, Patent Document 1).

[0003] However, when cleaning the back teeth, the gap between the back teeth and the inner wall of the oral cavity is narrow, and the edge of the head of the toothbrush collides with the inner wall, hindering the operability of the toothbrush.

[0004] JP 2018-114423 A

[0005] In view of this, the present invention provides a toothbrush that reduces collision with the oral wall that occurs when the head of the toothbrush is inserted deep into the oral cavity, thereby improving operability within the oral cavity.

[0006] The toothbrush of the present invention comprises a head portion in which multiple bristle bundles are planted at right angles to the bristle planting surface, a neck portion connected to the head portion, and a handle portion connected to the neck portion, wherein the head portion is composed of a base end portion extending longitudinally from the tip of the neck portion, and a tip end portion extending longitudinally from the tip of the base end portion via a step, and the tip end portion is inclined in the direction of the bristle tips of the brush bristle bundles.

[0007] In addition, the toothbrush of the present invention comprises a head portion in which multiple bristle bundles are planted at right angles to the bristle planting surface, a neck portion connected to the head portion, and a handle portion connected to the neck portion, wherein the head portion is composed of a base end portion extending longitudinally from the tip of the neck portion, and an outer edge portion extending from the outer edge of the base end portion via a step in an expansion direction that spreads out around the periphery, and the outer edge portion is inclined in the direction of the bristle tips from which the bristle bundles extend.

[0008] This toothbrush reduces collisions with the oral wall that occur when the toothbrush is inserted deep into the oral cavity, improving the operability of the toothbrush. Furthermore, with this toothbrush, the bristle bundles are planted at right angles to the bristle planting surface, allowing the bristle bundles to be planted efficiently and reliably in the head portion.

[0009] It is also preferable that the outer edge portion includes a tip portion extending from the tip of the base end portion along the longitudinal direction, and a pair of left and right side portions extending from the sides of the base end portion along the left and right width direction perpendicular to the longitudinal direction.

[0010] This type of toothbrush not only reduces the impact of the toothbrush head on the inner walls of the oral cavity when inserted deep inside the oral cavity, but also reduces the impact of the head on the inner walls of the oral cavity when brushing in an up-and-down direction inside the oral cavity.

[0011] Furthermore, the hair implantation surface includes a base-side implantation surface provided in the base-side portion and a tip-side implantation surface provided in the tip-side portion, and it is preferable that the base-side implantation surface and the tip-side implantation surface are parallel to each other and are formed in a stepped manner by the base-side implantation surface and the tip-side implantation surface.

[0012] Furthermore, it is preferable that the hair implantation surface includes a base-side implantation surface provided in the base-side portion and an outer-edge side implantation surface provided in the outer-edge side portion, and that the hair implantation surface extends from the base-side portion to the outer-edge side portion and is formed in a stepped manner by the base-side implantation surface and the outer-edge side implantation surface.

[0013] With such a toothbrush, the process of tufting the brush bristles can be carried out efficiently, and the brush bristles can be reliably tufted into the head portion.

[0014] It is also preferable that the base end implantation surface and the tip end implantation surface have a plurality of implantation holes of uniform depth into which the brush bristle bundles are implanted.

[0015] It is also preferable that the base end side implantation surface and the outer edge side implantation surface have a plurality of implantation holes of uniform depth into which the brush bristle bundles are implanted.

[0016] With such a toothbrush, the bristle bundles are planted in bristle planting holes of the same depth, making it easy to form the head with a uniform thickness and maintaining the strength of the head.

[0017] Preferably, the outer edge portion is formed in a substantially U-shape in plan view, with the tip portion and the pair of side portions being connected together.

[0018] The toothbrush head is made roughly U-shaped, which increases its strength. Furthermore, when using this toothbrush to rinse after cleaning the oral cavity, water flows out of the opening in the roughly U-shape, making it easy to remove any toothpaste or dirt remaining on the toothbrush.

[0019] To provide a toothbrush that reduces collision with the inner wall of the oral cavity when the toothbrush is inserted deep into the oral cavity, thereby improving operability in the oral cavity.

[0020] 11A is a perspective view showing a toothbrush according to a first embodiment of the present invention. FIG. 1 is a locally enlarged view showing the head of the toothbrush shown in FIG. 1. FIG. 2 is a cross-sectional view showing the A1-A1 line cross section of the head shown in FIG. 2. FIG. 3 is a schematic view showing the flat line when implanting bristle bundles into bristle implantation holes. FIG. 4 is a schematic view showing the flat line when implanting bristle bundles into bristle implantation holes. FIG. 5 is a schematic view showing intraoral cleaning using the toothbrush shown in FIG. 1. FIG. 6 is a schematic view showing intraoral cleaning using a conventional toothbrush. FIG. 11B is a perspective view showing a toothbrush according to a second embodiment of the present invention. FIG. 6 is a locally enlarged view showing the head of the toothbrush shown in FIG. 6. FIG. 7 is a cross-sectional view showing the A2-A2 line cross section of the head shown in FIG. 7. FIG. 7 is a cross-sectional view showing the B2-B2 line cross section of the head shown in FIG. 7. FIG. 8 is a locally enlarged view showing the head of a toothbrush according to a third embodiment of the present invention. FIG. 9 is a cross-sectional view showing the A3-A3 line cross section of the head shown in FIG. 9. FIG. 9 is a cross-sectional view showing the B3-B3 line cross section of the head shown in FIG. 9. FIG. 6A is a locally enlarged view showing the rear surface of the head shown in FIG. 6. FIG. 11B is a side view showing the lateral side of the head shown in FIG. 11A. Fig. 11B is a side view showing the tip side of the head part shown in Fig. 11A. Fig. 11C is a locally enlarged view showing the back surface of the head part shown in Fig. 9. Fig. 12B is a side view showing the lateral side of the head part shown in Fig. 12A. Fig. 12C is a side view showing the tip side of the head part shown in Fig. 12A.

[0021] A toothbrush 1 according to a first embodiment of the present invention will now be described. Fig. 1 is a perspective view showing the toothbrush 1 according to the first embodiment of the present invention. Fig. 2 is a partially enlarged view showing the head portion 2 of the toothbrush 1 shown in Fig. 1. Fig. 3 is a cross-sectional view taken along line A1-A1 of the head portion shown in Fig. 2.

[0022] The toothbrush 1 according to the first embodiment shown in Figures 1 to 3 includes a head portion 2 in which multiple bristle bundles 3 are planted in one direction relative to a bristle planting surface 20, a neck portion 5 connected to the head portion 2, and a grip portion 7 connected to the neck portion 5. The head portion 2, neck portion 5, and grip portion 7 can be formed using any commonly used synthetic resin without any particular restrictions. For example, it is preferable to use one or more of the following resins: polypropylene, polyacetal resin, polybutylene terephthalate resin, polystyrene resin, polyethylene terephthalate resin, acrylonitrile butadiene styrene resin, acrylonitrile styrene resin, cellulose propionate resin, polyarylate resin, polycarbonate resin, polyester, polytrimethylene terephthalate, and polycyclohexanedimethylene terephthalate. Particularly preferred are polyacetal resin, polybutylene terephthalate resin, acrylonitrile butadiene styrene resin, acrylonitrile styrene resin, polycarbonate resin, and polycyclohexane dimethylene terephthalate.

[0023] It is also preferable that the head portion 2, neck portion 5, and grip portion 7 are integrally formed. The brush bristle bundle 3 is formed of a plurality of filaments made of a resin having appropriate elasticity, such as a polyamide resin such as nylon or aramid resin, a polyester resin such as polyethylene terephthalate, polytrimethylene terephthalate, or polybutylene terephthalate, a polyolefin resin such as polypropylene, a thermoplastic elastomer resin, or any other conventionally known thermoplastic resin filament.

[0024] As shown in Figure 2, the head portion 2 is composed of a base portion 21 and a tip portion 23. The base portion 21 extends in the longitudinal direction from the tip of the neck portion 5. The tip portion 23 is inclined from the tip of the base portion 21 in the longitudinal direction toward the tips of the bristle bundles 3. Here, "inclined" includes not only the case where the tip portion 23 extends straight at a constant angle relative to the base portion 21, as in this example, but also cases where part or all of the tip portion 23 extends in a curved manner while changing the angle, and other forms.

[0025] The head portion 2 includes a bristle implantation surface 20 extending from a base end portion 21 to a tip end portion 23, and a bristle implantation surface 4 located on the opposite side of the bristle implantation surface 20. The bristle implantation surface 20 includes a base end implantation surface 201 provided in the base end portion 21 and a tip end implantation surface 203 provided in the tip end portion 23, and the base end implantation surface 201 and the tip end implantation surface 203 are perpendicular to the implantation direction of the brush bristle bundles 3. The bristle implantation surface 20 is formed in a stepped pattern with multiple steps from the tip of the base end portion 21 to the tip of the tip end portion 23 by interposing a wall surface 202 extending in the implantation direction of the brush bristle bundles 3 between the base end implantation surface 201 and the tip end implantation surface 203. The inclination of the tip side portion 23 refers to the inclination of an imaginary plane 230 passing through the thickness-wise intermediate position of the tip surface of the tip side portion 23 and the thickness-wise intermediate position of the tip of the base side portion 21, relative to an imaginary plane 210 passing through the thickness-wise intermediate position of the tip of the base side portion 21 and the thickness-wise intermediate position of the tip of the neck portion 5. Note that, although the number of steps from the tip of the base side portion 21 to the tip of the tip side portion 23 is three in this embodiment, the number of steps may be formed in a stepped manner depending on the number of bristle bundles 3 planted, and is not limited thereto.

[0026] As shown in FIG. 3 , the bristle implantation surface 20 may extend with a curved or bent wall surface 202, or preferably extends flat with a predetermined inclination relative to either the base-side implantation surface 201 or each distal-side implantation surface 203. The predetermined inclination may be such that the head portion 2, neck portion 5, and grip portion 7 can be easily released from the mold when they are molded. While not particularly limited, a range of 0 to 25 degrees is preferred. In this embodiment, the stepped bristle implantation surface 20 formed by the base-side implantation surface 201, wall surface 202, and each distal-side implantation surface 203 has three steps. However, the number of steps can be adjusted depending on the design of how the brush bristle bundles 3 are implanted. As shown in FIG. 3 , the stepped bristle implantation surface 20 formed by the base-side implantation surface 201, wall surface 202, and each distal-side implantation surface 203 may have different height differences, i.e., different step heights, but these differences are preferably equal. The step height per step is preferably 0.1 to 3 mm, and the total step height of the entire head portion 2 is preferably 0.1 to 6 mm.

[0027] A plurality of bristle implantation holes 22 into which the brush bristle bundles 3 are implanted are formed on the base-side implantation surface 201 and the tip-side implantation surface 203. The bristle implantation holes 22 are preferably perpendicular to the base-side implantation surface 201 and the tip-side implantation surface 203, and have a uniform depth. If the bristle implantation holes 22 have a uniform depth, the bristle bundles 3 implanted on the base-side implantation surface 201 and the tip-side implantation surface 203 will have approximately the same pluck strength.

[0028] 4A and 4B are schematic diagrams showing the flat wire 9 when the bristle bundle 3 is implanted in the bristle implantation hole 22. As shown in the distal end portion 23 of FIG. 4A, the bristle bundle 3 is pushed in along the bristle implantation hole 22 from one direction together with the flat wire 9, and the flat wire 9 acts as an anchor to implant the bristle bundle 3 in the bristle implantation hole 22. If the proximal implantation surface 201 and distal implantation surface 203 of the distal end portion 23A where the bristle bundle 3 is implanted are not perpendicular to the implantation direction, as shown in FIG. 4B, one side of the flat wire 9 will come into contact with the bristle implantation hole 22 and become tilted when the flat wire 9 is pushed along the bristle implantation hole 22. If the bristle bundle 3 is implanted in the bristle implantation hole 22 with the flat wire 9 in a tilted position, the bristle bundle 3 will be easily pulled out. If the bristle bundles 3 were to be implanted in a direction perpendicular to the inclined surface of the distal end portion 23A, the bristle bundles 3 would have to be implanted in at least two directions relative to the head portion 2, which would result in inefficiencies in the manufacturing process. Therefore, even if the flat wire 9 is pushed into the bristle implantation hole 22 opened along the implantation direction, the base end implantation surface 201 and the distal end implantation surface 203 are perpendicular to the implantation direction, so the flat wire 9 does not tilt, and the bristle bundles 3 can be reliably implanted in the head portion 2.

[0029] The bristle implantation holes 22 can be arranged as appropriate depending on the combination of bristle bundles 3 made of different materials, the shape of the bristle tips of the bristle bundles 3, etc. The arrangement of the bristle implantation holes 22 is not particularly limited as long as it allows the toothbrush 1 to exhibit its cleaning properties, and they can be arranged at equal intervals in the longitudinal direction and the left and right width directions, or in a staggered pattern.

[0030] 1, the brush bristle bundles 3 are implanted in each bristle implantation hole 22 with varying bristle heights depending on the base-side implantation surface 201 and the tip-side implantation surface 203, forming a brush section 30 with approximately flush bristle tips. The brush section 30 may also be formed with undulating bristle tips, such as a mountain cut, or the brush bristle bundles 3 may all have the same bristle length to form a brush section 30 with bristle tips shaped to conform to the stepped bristle implantation surface 20 formed by the base-side implantation surface 201 and the tip-side implantation surface 203. This is not a limitation as long as it does not impair the operability of the toothbrush in the oral cavity and improves cleaning performance.

[0031] The back surface 29 is composed of a base-side back surface 291 provided in the base-side portion 21 and a tip-side back surface 293 provided in the tip-side portion 23. The base-side back surface 291 preferably extends substantially flat from the neck portion 5, and may have a step between it and the neck portion 5. The tip-side back surface 293 curves from the tip of the base-side back surface 291 toward the edge of the tip-side portion 23 of the uppermost step surface of the tip-side implantation surface 203, while corresponding to the stepped shape of the tufting surface 20 and the bottom positions of the tufting holes 22. The degree of inclination of the tip-side portion 23 with respect to the base-side portion 21 is preferably set to an angle H of 1 to 55 degrees, relative to the base-side back surface 291, taking into consideration the ability of the toothbrush 1 to clean the back of the oral cavity and the durability of the head portion 2 against brushing pressure.

[0032] Fig. 5A is a schematic diagram showing cleaning inside the oral cavity using the toothbrush 1 shown in Fig. 1. Fig. 5B is a schematic diagram showing cleaning inside the oral cavity using a conventional toothbrush B. When the conventional toothbrush B is inserted up to a tooth T close to the pharynx, as shown in Fig. 5B, the tip of the toothbrush B collides with the oral cavity wall W. In contrast, as shown in Fig. 5A, even when the toothbrush 1 according to the present invention is inserted up to a tooth T close to the pharynx, as with the conventional toothbrush B, the tip of the toothbrush 1 according to the present invention is less likely to collide with the oral cavity wall W because the tip-side back surface 293 of the tip portion 23 is inclined toward the bristle surface 20.

[0033] Furthermore, it is preferable that the bristle tips of the bristle bundles 3 of the bristle part 30 be formed so that the bristle length is long in the base end portion 21 and short in the tip end portion 23, so that the bristle tips are approximately flush. This narrows the tip of the toothbrush 1 in the direction in which the bristle bundles 3 are planted, making it easier to insert the toothbrush 1 even if the gap between the teeth T or gums G and the oral cavity wall W is narrow.

[0034] In addition, the bristle bundles 3 implanted on the distal implantation surface 203 are shorter than the bristle bundles 3 implanted on the proximal implantation surface 201, and therefore have a firmer bristle structure than the bristle bundles 3 implanted on the proximal implantation surface 201, improving cleaning performance for the tooth surface. On the other hand, the bristle bundles 3 implanted on the proximal implantation surface 201 are longer than the bristle bundles 3 implanted on the distal implantation surface 203, and therefore have a softer bristle structure than the bristle bundles 3 implanted on the distal implantation surface 203, improving cleaning performance for between teeth. In addition, because the bristle bundles 3 implanted on the bristle implantation surface 20 are all aligned in one direction, brushing pressure is evenly distributed across the bristle part 30, improving cleaning performance.

[0035] A toothbrush 1 according to a second embodiment of the present invention will now be described. Fig. 6 is a perspective view showing the toothbrush 1 according to the second embodiment of the present invention. Fig. 7 is a locally enlarged view showing the head unit 4 of the toothbrush 1 shown in Fig. 6. Fig. 8A is a cross-sectional view showing the cross section of the head unit 4 shown in Fig. 7, taken along line A2-A2. Fig. 8B is a cross-sectional view showing the cross section of the head unit 4 shown in Fig. 7, taken along line B2-B2. Note that a description of the parts corresponding to the first embodiment will be omitted, and the description will focus on the technical features of the second embodiment that differ from the first embodiment.

[0036] The toothbrush 1 according to the second embodiment shown in Figures 6 to 8B, like the first embodiment, comprises a head portion 4 in which multiple bristle bundles 3 are each planted in one direction relative to a bristle planting surface 40, a neck portion 5 connected to the head portion 4, and a grip portion 7 connected to the neck portion 5.

[0037] 7, the head portion 4 is composed of a base end portion 41 and an outer edge portion 43. The base end portion 41 extends in the longitudinal direction from the tip of the neck portion 5. The outer edge portion 43 extends in an expanding direction from the outer edge side of the base end portion 41 and is inclined toward the bristle tips of the brush bristle bundles 3. The outer edge portion 43 includes a tip portion 431 extending in the longitudinal direction from the tip of the base end portion 41, and a pair of left and right side portions 433, 433 extending in the left and right width direction from the sides of the base end portion 41, perpendicular to the longitudinal direction.

[0038] Furthermore, it is preferable that the outer edge portion 43 is formed in a substantially U-shape with the tip portion 431 and a pair of side portions 433, 433 connected to each other and facing the neck portion 5. This prevents saliva and toothpaste that overflows during oral cavity cleaning from flowing out of the substantially U-shaped opening 400 and dripping into unexpected places. Furthermore, the strength of the head portion 4 is ensured by the tip portion 431 and the pair of side portions 433, 433 connected to each other and forming a substantially U-shape.

[0039] The head portion 4 includes a bristle implantation surface 40 extending from the base end portion 41 to the outer edge portion 43, and a back surface 49 located on the opposite side of the bristle implantation surface 40. The bristle implantation surface 40 includes a base end implantation surface 401 provided in the base end portion 41, a tip end implantation surface 404 provided in the tip portion 431, and a lateral implantation surface 405 provided in the lateral portion 433, and the base end implantation surface 401, the tip end implantation surface 404, and the lateral implantation surface 405 are perpendicular to the implantation direction of the brush bristle bundles 3.

[0040] 7, 8A, and 8B, the distal implantation surface 404 and the pair of lateral implantation surfaces 405, 405 are connected in this order to form the outer peripheral implantation surface 403. The implantation surface 40 is formed in a two-step staircase shape from the tip of the proximal portion 41 to the tip of the outer peripheral portion 43 by interposing a wall surface 402 extending in the implantation direction of the bristle bundles 3 between the proximal implantation surface 401 and the outer peripheral implantation surface 403. The inclination of the distal end 431 of the outer peripheral portion 43 refers to the inclination of an imaginary plane 432 passing through the thickness-wise midpoint of the distal end surface of the distal end 431 and the thickness-wise midpoint of the tip of the proximal portion 41, relative to an imaginary plane 434 passing through the thickness-wise midpoint of the tip of the proximal portion 41 and the thickness-wise midpoint of the tip of the neck portion 5. Furthermore, the inclination of the lateral portion 433 of the outer edge portion 43 refers to the inclination of an imaginary plane 436 passing through the thickness-wise midpoint of the outer surface of the lateral portion 433 and the thickness-wise midpoint of the central portion of the base end portion 41 relative to an imaginary plane 438 passing through the thickness-wise midpoint of the central portion of the base end portion 41 and the thickness-wise midpoint of the tip of the neck portion 5.

[0041] Fig. 9 is a locally enlarged view showing the head portion 4 of a toothbrush 1 according to a third embodiment of the present invention. Fig. 10A is a cross-sectional view showing a cross section of the head portion 4 shown in Fig. 9 taken along line A3-A3. Fig. 10B is a cross-sectional view showing a cross section of the head portion 4 shown in Fig. 9 taken along line B3-B3. In the toothbrush 1 according to the third embodiment, which is a variation of the second embodiment, as shown in Figs. 9, 10A, and 10B, a single step is formed between the tip of the base end portion 41 and the tip of the outer edge portion 43, with the wall surface 402 interposed therebetween. The step-like formation between the tip of the base end portion 41 and the tip of the outer edge portion 43 may be determined depending on the number of bristle tufts 3 to be planted, the layout design of the bristle tufts 3, and the like, and the number of steps is not limited.

[0042] 8A , 8B , 10A , and 10B , the wall surfaces 402 of the bristle implantation surface 40 may extend while being curved or bent, or preferably extend flatly while being inclined with respect to either the base-side implantation surface 401 or each outer-side implantation surface 403. The inclination may be such that the head portion 4, neck portion 5, and grip portion 7 can be easily released from the mold when they are molded, and is not particularly limited, but is preferably between 0 and 25 degrees. In this embodiment, the stepped bristle implantation surface 40 formed by the base-side implantation surface 401, wall surfaces 402, and each outer-side implantation surface 403 may have two or one step, but the number of steps is not limited because it can be adjusted depending on the design of how the brush bristle bundles 3 are implanted. 8A, 8B, 10A, and 10B, the height difference, i.e., the step height, of the stepped implantation surface 40 formed by the base end implantation surface 401, the wall surface 402, and the outer edge implantation surfaces 403 may be different from each other, but is preferably equal. The step height per step is preferably 0.1 to 3 mm, and the total step height of the entire head portion 4 is preferably 0.1 to 6 mm.

[0043] A plurality of bristle implantation holes 42 into which the bristle bundles 3 are implanted are formed in each of the base-side implantation surface 401 and the outer-side implantation surface 403. The bristle implantation holes 42 are preferably perpendicular to the base-side implantation surface 401 and the outer-side implantation surface 403 and have a uniform depth. If the bristle implantation holes 42 have a uniform depth, the bristle bundles 3 implanted in the base-side implantation surface 401 and the outer-side implantation surface 403 will have approximately the same pluck strength. The bristle implantation holes 42 can be arranged appropriately depending on the combination of bristle bundles 3 made of different materials, the shape of the bristle tips of the bristle bundles 3, etc. The bristle implantation holes 42 can be arranged at equal intervals in the longitudinal direction and the left and right width directions, or in a staggered pattern. The arrangement of the bristle implantation holes 42 is not particularly limited as long as the toothbrush 1 can exhibit its cleaning properties.

[0044] FIG. 11A is a locally enlarged view showing the back surface of the head unit 4 shown in FIG. 6. FIG. 11B is a side view showing the lateral side of the head unit shown in FIG. 11A. FIG. 11C is a side view showing the distal end side of the head unit shown in FIG. 11A. FIG. 12A is a locally enlarged view showing the back surface of the head unit 4 shown in FIG. 9. FIG. 12B is a side view showing the lateral side of the head unit shown in FIG. 12A. FIG. 12C is a side view showing the distal end side of the head unit shown in FIG. 12A. As shown in FIGS. 11A to 11C and 12A to 12C, the back surface 49 according to the second and third embodiments is composed of a base-side back surface 491 provided in the base-side portion 41 and an outer-edge-side back surface 493 provided in the outer-edge-side portion 43. The base-side back surface 491 preferably extends substantially flat from the neck unit 5, and there may be a step between the base-side back surface 491 and the neck unit 5. The outer edge back surface 493 bends from the outer edge of the base back surface 291 toward the end edge of the tip portion 431 of the top surface of the tip implantation surface 404 and the end edges of the lateral portions 433 of the top surfaces of the pair of lateral implantation surfaces 405, 405, while corresponding to the stepped shape of the tufting surface 40 and the bottom positions of the tufting holes 42. The base back surface 491 is provided substantially flat, continuing from the tip of the neck portion 5. The degree of inclination of the outer edge portion 43 relative to the base portion 41 is preferably set at an angle H of 1 to 55 degrees, relative to the base back surface 491, in consideration of the ability of the toothbrush 1 to clean the back of the oral cavity and the durability of the head portion 2 against brushing pressure.

[0045] As a result, the toothbrush 1 of the first embodiment and the toothbrush 1 of the third embodiment not only reduce impact on the inner walls of the oral cavity when inserted deep inside the oral cavity, but also reduce impact of the head portion on the inner walls of the oral cavity when brushing in an up and down direction inside the oral cavity.

[0046] In order to show the configuration of the head portion 2 and the head portion 4, for convenience, the brush bristle bundles 3 implanted in the head portion 2 and the head portion 4 are not shown in Figures 2 to 4B and 7 to 10B, but in reality, the brush bristle bundles 3 are implanted.

[0047] Although the embodiments of the present invention have been described above, the present invention is not limited to these examples, and it goes without saying that the present invention can be embodied in various forms without departing from the spirit of the present invention.

[0048] DESCRIPTION OF SYMBOLS 1 Toothbrush 2 Head portion 3 Bristle bundle 4 Head portion 5 Neck portion 7 Grip portion 9 Flat line 20 Bristle implantation surface 21 Base end portion 22 Bristle implantation hole 23 Tip end portion 23A Tip end portion 29 Back surface 30 Bristle portion 40 Bristle implantation surface 41 Base end portion 42 Bristle implantation hole 43 Outer edge portion 49 Back surface 201 Base end implantation surface 202 Wall surface 203 Tip end implantation surface 210 Virtual surface 230 Virtual surface 291 Base end back surface 293 Tip end back surface 400 Opening 401 Base end implantation surface 402 Wall surface 403 Outer edge side implantation surface 404 Tip end implantation surface 405 Lateral implantation surface 431 Tip portion 432 Imaginary surface 433 Lateral portion 434 Imaginary surface 436 Imaginary surface 438 Imaginary surface 491 Proximal back surface 493 Peripheral back surface B Conventional toothbrush G Gums H Angle T Tooth W Inner wall of oral cavity

Claims

1. A toothbrush having a head portion in which multiple bristle bundles are each planted at a right angle to the bristle planting surface, a neck portion connected to the head portion, and a handle portion connected to the neck portion, wherein the head portion is composed of a base end portion extending in the longitudinal direction from the tip of the neck portion, and a tip end portion extending in the longitudinal direction from the tip of the base end portion via a step, and the tip end portion is inclined in the direction of the bristle tips from which the bristle bundles extend.

2. The toothbrush of claim 1, wherein the bristle implantation surface includes a base implantation surface provided in the base portion and a tip implantation surface provided in the tip portion, and the base implantation surface and the tip implantation surface are parallel to each other, and the base implantation surface and the tip implantation surface form a stepped shape.

3. A toothbrush having a head portion in which multiple bristle bundles are each planted at right angles to the bristle planting surface, a neck portion connected to the head portion, and a handle portion connected to the neck portion, wherein the head portion is composed of a base end portion extending in the longitudinal direction from the tip of the neck portion, and an outer edge portion extending from the outer edge side of the base end portion via a step in an expansion direction spreading out around, and the outer edge portion is inclined in the direction of the bristle tips from which the bristle bundles extend.

4. The toothbrush of claim 3, wherein the outer edge portion includes a tip portion extending longitudinally from the tip of the base end portion, and a pair of left and right side portions extending from the sides of the base end portion along a left-right width direction perpendicular to the longitudinal direction.

5. A toothbrush as described in claim 3 or 4, wherein the bristle implantation surface includes a base end implantation surface provided in the base end portion and an outer edge side implantation surface provided in the outer edge side portion, and the bristle implantation surface extends from the base end portion to the outer edge side portion and is formed in a stepped manner by the base end implantation surface and the outer edge side implantation surface.

6. The toothbrush according to claim 5, wherein the outer edge portion is formed into a substantially U-shape in a plan view by connecting the tip portion and the pair of left and right side portions.

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