Hair iron

Abstract

To provide a hair iron capable of arranging a hair style excellently without damaging hair.SOLUTION: A hair iron includes arm parts 13A, 13B extending from a base end part 12. The arm parts 13A, 13B include a surface plate 42, a carbon-containing heat conduction layer 43 spread along the rear face of the surface plate 42, and a heat generator 44 arranged on the reverse side of the carbon-containing heat conduction layer 43.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a hair iron.

Background Art

[0002] Conventionally, hair irons used for arranging hairstyles are known. For example, the hair iron described in Patent Document 1 below includes a pair of iron pieces connected so as to be openable and closable. A user sandwiches hair between the pair of iron pieces, applies heat to the hair, and arranges the hairstyle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a desire to arrange a hairstyle well without damaging the hair with a hair iron as described above.

[0005] The present invention has been completed based on the above circumstances, and an object thereof is to provide a hair iron capable of arranging a hairstyle well without damaging the hair.

Means for Solving the Problems

[0006] The hair iron of the present invention includes an arm portion extending from a base end portion, and the arm portion includes a surface plate, a carbon-containing heat conduction layer extending along the back surface of the surface plate, and a heating element disposed on the back side of the carbon-containing heat conduction layer.

Effects of the Invention

[0007] According to the present invention, the heat from the heating element is transferred to the surface plate in the planar direction by the carbon-containing heat conductive layer, making it easier to achieve a uniform temperature on the surface plate. Furthermore, because the carbon-containing heat conductive layer generates far-infrared rays, it is possible to heat the hair to its deepest layers while suppressing thermal damage to the hair surface. Therefore, hairstyles can be styled well without damaging the hair. [Brief explanation of the drawing]

[0008] [Figure 1] Perspective view showing the hair iron in this embodiment [Figure 2] A cross-sectional view showing a hair iron in the open position. [Figure 3] Partially enlarged perspective view showing the vicinity of the switch. [Figure 4] Enlarged longitudinal section showing a portion of the base end in the locked state. [Figure 5] Enlarged plan view showing a portion of the base end of the locking member when it is positioned in the locked position. [Figure 6] Enlarged plan view showing a portion of the base end of the locking member in the unlocked position. [Figure 7] A partially cutaway perspective view showing the locking mechanism in the locked state. [Figure 8] A partially cutaway perspective view showing the lock mechanism in the unlocked state. [Figure 9] Vertical cross-sectional view showing the clamping portion of the upper arm. [Figure 10] Plan view of the clamping portion of the upper arm, seen from below. [Figure 11] Exploded perspective view showing the clamping portion of the upper arm. [Figure 12] A flowchart showing the process when a power supply is connected to a hair iron. [Figure 13] Table showing the configuration of the conical coil spring in the comparative example. [Figure 14] Diagram showing the configuration of a conical coil spring in a comparative example. [Figure 15] Table showing the calculation results of load and deflection for the comparative example conical coil spring. [Figure 16]Graph showing the load-deflection curve of the conical coil spring of the comparative example

Mode for Carrying Out the Invention

[0009] Preferred embodiments of the present invention are shown below.

[0010] In the hair iron of the present invention, the carbon-containing heat conduction layer may include a graphite sheet. According to such a configuration, the carbon-containing heat conduction layer can be made thinner, and the hair iron can be miniaturized. In addition, the surface temperature of the surface plate can be made uniform, so that uneven protein denaturation of the hair due to local temperature rise can be less likely to occur.

[0011] Also, in the hair iron of the present invention, the carbon-containing heat conduction layer may have flexibility. According to such a configuration, the carbon-containing heat conduction layer does not break, so it can be easily handled.

[0012] Also, in the hair iron of the present invention, the heating element may include a film heater. According to such a configuration, the heating element can be made thinner and the arm portion can be miniaturized. The heat of the film heater spreads in the plane direction from the heater wire by the carbon-containing heat conduction layer. Therefore, while miniaturizing the arm portion, the temperature of the surface plate can be made uniform in the plane direction.

[0013] Also, the hair iron of the present invention may have a battery housing portion for housing a battery and may be operated by the power from the battery. According to such a configuration, it can be used in places without a power outlet, so it can be easily used for portable purposes.

[0014] Furthermore, the hair iron of the present invention may have a USB cable port and be connectable to a power supply via the USB cable. When the output of the power supply is higher than a predetermined value, it operates using power from the power supply, and when the output of the power supply is lower than a predetermined value, it operates using power from the battery. With such a configuration, when a power supply with an output higher than a predetermined value is connected, it operates using power from the power supply, thus extending battery life and allowing use even when the battery is not charged. When a power supply with an output lower than a predetermined value is connected, it operates using power from the battery, preventing performance degradation due to insufficient output.

[0015] <Examples> Hereinafter, an embodiment of the present invention will be described in detail with reference to Figures 1 to 16. In this embodiment, the hair iron 10 is used to style a hairstyle. The hair iron 10 is a straight iron and, as shown in Figure 1, has a pair of arm portions 13A and 13B connected at the base end 12. The hair iron 10 is used to style a hairstyle by opening the pair of arm portions 13A and 13B, placing hair between them, and applying heat to the hair. When the hair iron 10 is not in use, the pair of arm portions 13A and 13B are closed.

[0016] Hereinafter, in the hair iron 10, the state in which the pair of arm portions 13A and 13B are open will be referred to as the open state, and the state in which the pair of arm portions 13A and 13B are closed will be referred to as the closed state. In the description of each component, the positive Y-axis side in Figure 1 (the side on which the display portion 14 is provided) will be referred to as the upper side, the negative Y-axis side in Figure 1 will be referred to as the lower side, the positive X-axis side (the tip side of the arm portions 13A and 13B) will be referred to as the front side, and the negative X-axis side (the side on which the base portion 12 is provided) will be referred to as the rear side. The X-axis direction refers to the front-to-back direction or the length direction, the Y-axis direction refers to the up-and-down direction or the thickness direction, and the Z-axis direction refers to the left-to-right direction or the width direction. In the description of each arm portion 13A and 13B, the sides of the pair of arm portions 13A and 13B that are opposite each other will be referred to as the inner side or the front side, and the side opposite to the opposite side will be referred to as the outer side or the back side.

[0017] The display unit 14 is provided on the outer surface of the upper arm portion 13A. The display unit 14 has, for example, an LED. The display unit 14 shows the power on / off status, set temperature, charging status, etc.

[0018] The hair iron 10 comprises a clamping section 15 for holding hair and a gripping section 16 for the user to hold. The clamping section 15 is the front part of the hair iron 10. The gripping section 16 is the rear part of the hair iron 10. In the closed state, the length, width, and thickness dimensions of the clamping section 15 are smaller than the length, width, and thickness dimensions of the gripping section 16.

[0019] The hair iron 10 is equipped with a cap case 17. The cap case 17 is placed over the closed clamping portion 15 from the front.

[0020] The hair iron 10 is equipped with a comb-like section 18. The comb-like section 18 is provided on both the left and right sides of the clamping section 15. The comb-like section 18 is formed along both the left and right edges of the housing 24, which will be described later, and extends for approximately the entire length of the clamping section 15 (see Figure 10). The comb-like section 18 has a plurality of protrusions 19 arranged in the front-to-back direction. Each protrusion 19 is triangular in shape with a pointed end and is arranged at equal intervals. By providing the comb-like section 18, the surface area of ​​the housing 24 can be increased, heat can be dissipated efficiently, and the temperature of the housing 24 can be reduced more easily.

[0021] The hair iron 10 has a USB cable 21 connector 22. The connector 22 is compatible with USB Type-C. The connector 22 is located at the base end 12 of the upper arm portion 13A and opens to the rear. The hair iron 10 is connected to a power supply unit (not shown) via the USB cable 21. The power supply unit can be one that complies with the USB PD (Power Delivery) standard.

[0022] As shown in Figure 2, the pair of arm portions 13A and 13B are displaceable between an open state and a closed state around a hinge portion 23 provided at the base end portion 12. Figure 2 shows the hair iron 10 in the open state. The pair of arm portions 13A and 13B each extend linearly forward from the base end portion 12.

[0023] Each arm section 13A, 13B is equipped with a housing 24 that is elongated in the front-to-back direction. The components that make up the hair iron 10 are housed inside the housing 24. The cross-section of the housing 24 is curved in an arc shape, as shown in Figure 7. The left and right edges of the housing 24 are located on the front side of the housing 24's center in the left-to-right direction.

[0024] As shown in Figure 2, the housing 24 has a battery compartment 26 for housing the battery 25. The battery 25 is a rechargeable secondary battery such as a lithium-ion battery. The battery 25 is charged by connecting a power supply via a USB cable 21. The hair iron 10 operates using power supplied from the battery 25.

[0025] The battery compartment 26 is located on the gripping portion 16 of the lower arm portion 13B. The front side of the battery compartment 26 is closed by a battery cover 27. The battery cover 27 is removable. By removing the battery cover 27, the batteries 25 in the battery compartment 26 can be inserted and removed.

[0026] As shown in Figure 3, the hair iron 10 is equipped with a switch 28 for switching the power on and off and for setting the temperature of the heating element 44, which will be described later. The switch 28 is located on the inner surface of the upper arm portion 13A. By having the switch 28 located on the inner surface of the upper arm portion 13A, accidental operation can be prevented more effectively than if it were located on the outer surface. The switch 28 is slidable in the front-back direction. The power-off position of the switch 28 is located further back than the power-on position. Figure 3 shows the switch 28 in the power-on position. When the cap case 17 is placed over the clamping portion 15, the switch 28 in the power-on position is pushed to the rear by the pressing portion 17A provided on the cap case 17, moving to the power-off position.

[0027] As shown in Figure 4, the base end portion 12 has a locking portion 30 that holds the pair of arm portions 13A and 13B in a closed state. The locking portion 30 has a first locking portion 31 provided on the upper side and a second locking portion 32 provided on the lower side. The first locking portion 31 and the second locking portion 32 come into contact with each other when the pair of arm portions 13A and 13B attempt to displace from the closed state to the open state, thereby suppressing further displacement.

[0028] The first locking portion 31 protrudes downward from the housing 24 of the upper arm portion 13A.

[0029] The second locking portion 32 is provided on the locking member 33 held by the lower arm portion 13B. The locking member 33 swings from side to side between a locked position (see Figure 5) and an unlocked position (see Figure 6) around the rotating shaft portion 33A. In Figures 5 and 6, dashed lines show the first locking portion 31 projected downwards.

[0030] As shown in Figure 4, the locking member 33 comprises a main body 34 and an operating part 35. The main body 34 is plate-shaped. The second locking part 32 protrudes upward from the main body 34. The main body 34 has a locking retaining part 36 that holds the position of the locking member 33. The locking retaining part 36 is a recess formed on the back surface of the main body 34. The locking retaining part 36 fits into a projection 37 provided on the lower arm 13B. The projection 37 is elastically displaced vertically by a spring member 38. The elastic force of the spring member 38 acts in a direction that moves the projection 37 upward.

[0031] A pair of locking retaining parts 36 are provided on the left and right sides. As shown in Figure 5, the locking member 33 is held in the locked position when the left locking retaining part 36 fits onto the projection 37. As shown in Figure 6, the locking member 33 is held in the unlocked position when the right locking retaining part 36 fits onto the projection 37.

[0032] The operating section 35 is provided protruding from the rear surface of the main body 34. The operating section 35 protrudes rearward from the housing 24. By moving the operating section 35 left or right, the position of the second locking section 32 can be changed to the locked position or the unlocked position. At this time, the projection 37 undergoes elastic displacement, giving the user a click sensation.

[0033] As shown in Figure 7, the contact surfaces 31A and 32A of the first locking portion 31 and the second locking portion 32 are inclined surfaces. When the contact surfaces 31A and 32A come into contact with each other in the vertical direction, a force is generated on the contact surfaces 31A and 32A that pushes the second locking portion 32 in the unlocking direction (to the left in Figure 7). When the force pushing the second locking portion 32 in the unlocking direction becomes greater than the force that displaces the projection portion 37 downward, the lock holding portion 36 detaches from the projection portion 37, and the locking member 33 moves to the unlocked position (see Figure 8).

[0034] The clamping portion 15 of the upper arm portion 13A and the clamping portion 15 of the lower arm portion 13B have generally the same configuration. Here, the configuration of the clamping portion 15 of the upper arm portion 13A will be explained, and the configuration of the clamping portion 15 of the lower arm portion 13B will not be explained.

[0035] The clamping portions 15 of the upper and lower arm portions 13A and 13B each include a plate 40 and an elastic member 41, as shown in Figure 9.

[0036] As shown in Figure 10, the plate 40 is a roughly rectangular plate that is long in the front-to-back direction. The length dimension of the surface of the plate 40 is 60 mm and the width dimension is 12 mm. As shown in Figure 11, the plate 40 comprises, in order from the front side, a surface plate 42, a carbon-containing heat conductive layer 43, a heating element 44, a heat conductive layer 45, a temperature sensor 46, an elastic sheet 47, an insulating sheet 48, a retaining member 49, a thermal fuse 51, and a bracket 52.

[0037] The surface plate 42 is a roughly rectangular plate that is long in the front-to-back direction. The surface plate 42 forms a contact surface that comes into contact with the hair. Multiple holes 53 are formed in the surface plate 42 that penetrate in the front-to-back direction. The holes 53 are arranged at equal pitches along the length of the surface plate 42. The front side of the surface plate 42 is covered with a low-friction sheet. The surface plate 42 has a peripheral wall 54 along its outer edge. The peripheral wall 54 surrounds the outer periphery of the carbon-containing heat conductive layer 43, the heating element 44, the heat conductive layer 45, the elastic sheet 47, the insulating sheet 48, and the retaining member 49. The peripheral wall 54 has multiple protrusions 54A that project to the back side. The protrusions 54A guide the displacement of the plate 40 in the front-to-back direction relative to the housing 24.

[0038] The carbon-containing thermal conductive layer 43 is made of a graphite sheet. The carbon-containing thermal conductive layer 43 is rectangular in shape, elongated in the front-to-back direction, and has the same size as the back surface of the surface plate 42. The thickness of the carbon-containing thermal conductive layer 43 is uniform. The carbon-containing thermal conductive layer 43 is a thin sheet and is flexible. Because the carbon-containing thermal conductive layer 43 is flexible, it is less likely to crack even though it is thin. The thinness of the carbon-containing thermal conductive layer 43 allows for effective use of the space inside the housing 24. Because the carbon-containing thermal conductive layer 43 is made of a graphite sheet, the surface temperature of the surface plate 42 can be made uniform. This makes it less likely for uneven protein denaturation of hair to occur due to localized temperature increases.

[0039] The carbon-containing heat conductive layer 43 contains a large amount of carbon and has a higher thermal conductivity than metal. The carbon-containing heat conductive layer 43 is sandwiched between the surface plate 42 and the heating element 44. By providing the carbon-containing heat conductive layer 43, which has high thermal conductivity, between the surface plate 42 and the heating element 44, the heat from the heating element 44 is quickly transferred to the surface plate 42. In addition, the heat from the heating element 44 is quickly transferred in the planar direction of the carbon-containing heat conductive layer 43, raising the temperature of the entire surface plate 42 uniformly. The carbon-containing heat conductive layer 43 emits far-infrared rays due to the heat. The far-infrared rays are radiated to the hair through the holes 53 in the surface plate 42.

[0040] The heating element 44 is a flexible, planar heating element. The heating element 44 is composed of a film heater in which a heater wire (not shown) is arranged on an insulating film. The heater wire is arranged across the entire surface of the film. The heating element 44 is a roughly elongated rectangle in the front-to-back direction. The heating element 44 is thin and lightweight. Electrodes are provided at both the front and rear ends of the heating element 44. The electrodes are fixed to the back surface of the retaining member 49 (see Figure 9).

[0041] The thermal conductive layer 45 is made of a metal foil with high thermal conductivity (e.g., aluminum foil). The thermal conductive layer 45 is roughly rectangular in shape, elongated in the front-to-back direction, and spreads thinly across the entire back surface of the heating element 44. The thermal conductive layer 45 is attached to the back surface of the heating element 44. The thermal conductive layer 45 efficiently transmits the temperature of the heating element 44 to the temperature sensor 46. The thermal conductive layer 45 and the carbon-containing thermal conductive layer 43 are roughly the same size.

[0042] The temperature sensor 46 is an NTC thermistor or the like. The temperature sensor 46 detects the temperature of the heating element 44.

[0043] The elastic sheet 47 presses the temperature sensor 46 against the heat conductive layer 45 (see Figure 9). The elastic sheet 47 is a silicone sheet. The components constituting the plate 40 are in close contact with each other due to the elastic sheet 47. The elastic sheet 47 has a projection 55 that secures the insulating sheet 48.

[0044] The insulating sheet 48 is a mica sheet. The insulating sheet 48 insulates the components that make up the plate 40.

[0045] The retaining member 49 is a roughly rectangular plate that is long in the front-to-back direction. The retaining member 49 is provided with an arrangement section 56 for arranging the thermal fuse 51.

[0046] The bracket 52 is a roughly rectangular plate that is long in the front-to-back direction. The bracket 52 fixes the thermal fuse 51 between itself and the retaining member 49. Both the front and rear ends of the bracket 52 have protruding pieces 52A that hook onto the housing 24. This prevents the plate 40 from coming off.

[0047] The bracket 52 has a positioning portion 57 for positioning the elastic member 41. The positioning portion 57 is provided protruding from the back surface of the bracket 52. The positioning portion 57 is provided at two locations on the front and rear of the bracket 52. The positioning portion 57 is located on both the front and rear sides of the thermal fuse 51 (see Figure 9).

[0048] As shown in Figure 9, the elastic member 41 supports the back side of the plate 40. The plate 40 is held suspended from the housing 24 by the elastic member 41. The elastic member 41 is positioned at two locations, front and rear. The elastic member 41 is tapered in side view. The elastic member 41 is circular in plan view (see Figure 10). The elastic member 41 has a nonlinear spring characteristic in which it is more easily compressed when the load from the front to the back is small than when it is large. In other words, the resistance of the elastic member 41 to deformation is constant in the initial stages of compression, and increases as the amount of compression increases from the middle of the compression onward. The maximum axial compression amount of the elastic member 41 is, for example, 1.5 mm. Due to the large maximum compression amount of the elastic member 41, the plate 40 can be displaced significantly in the front-to-back direction.

[0049] One end of the elastic member 41 in the axial direction is a small-diameter portion 41A, and the other end is a large-diameter portion 41B. The diameter of the small-diameter portion 41A is smaller than the diameter of the large-diameter portion 41B. The small-diameter portion 41A is positioned on the plate 40 side, and the large-diameter portion 41B is positioned on the housing 24 side. The small-diameter portion 41A fits onto the outer circumference of the positioning portion 57 provided on the bracket 52.

[0050] The elastic member 41 is a conical coil spring. The conical coil spring has nonlinear elasticity, meaning it is easier to compress when the load from the front to the back is small than when it is large. The conical coil spring has the advantage that the coil portion does not interfere with each other when compressed. The relationship between the load and deflection of the conical coil spring is nonlinear. Therefore, the larger the load on the conical coil spring, the smaller the change in the deflection of the conical coil spring.

[0051] The user experience of a hair iron 10 was compared using three conical coil springs with different spring characteristics (referred to as spring 1, spring 2, and spring 3). The configurations of springs 1, 2, and 3 are shown in Figures 13 and 14. The table in Figure 13 shows the material, shear modulus, wire diameter, minimum average diameter, maximum average diameter, number of turns, number of turns on the side seat at the maximum diameter, number of turns on the side seat at the minimum diameter, spring constant, pitch angle, and effective coil free height for each spring 1, 2, and 3.

[0052] The loads on springs 1, 2, and 3 were calculated using formula 1 below. The deflections on springs 1, 2, and 3 were calculated using formula 2 below. Calculation formula 1: π×d 4 ×G×(α-d´ / (2×π×Rs)) / (32×Rs 2 ) Calculation formula 2: n / (R2-R1)×16×P×(Rs 4 -R1 4 ) / (G×d 4 ) + π × α × (R² 2 -Rs 2 )-d'×(R2-Rs)) In calculation formulas 1 and 2, d is the wire diameter, G is the shear modulus, α is the pitch angle, d' is the contact pitch in the height direction, Rs is the bonding start radius, R1 is the minimum average radius, R2 is the maximum average radius, and P is the load.

[0053] The load and deflection of springs 1, 2, and 3 were calculated using formulas 1 and 2. The calculation results and graphs are shown in Figures 15 and 16. According to the graph in Figure 16, the load required to achieve the same amount of deflection is largest for spring 3 and smallest for spring 1.

[0054] The usability of the hair iron 10 using springs 1, 2, and 3 as elastic members 41 was evaluated by several hairdressers. The results are as follows: The usability of the hair iron 10 using spring 3 as elastic member 41 is better than that of the hair iron 10 using springs 1 and 2 as elastic members 41. The usability of the hair iron 10 using spring 2 as elastic member 41 is better than that of the hair iron 10 using spring 1 as elastic member 41. According to these evaluation results, it can be seen that the more tactile feedback the user receives from the displacement of the plate 40, the better the usability is perceived to be. In other words, the user feels that the movement of their fingertips is easily transmitted to the plate 40 because they can easily displace the plate 40 with little force, and they can feel the displacement of the plate 40.

[0055] Next, an example of how to use the hair iron 10 of this embodiment will be described. The hair iron 10 is palm-sized, with small length and width dimensions. Because the plates 40 of the hair iron 10 are small, it is suitable for detailed styling such as bangs and sideburns.

[0056] Charging of battery 25 begins when the USB cable 21 is plugged into the hair iron 10 and the power supply is connected. The display unit 14 indicates when battery 25 is fully charged. Once battery 25 is fully charged, unplug the USB cable 21. The hair iron 10 is cordless, making it suitable for use on the go.

[0057] The hair iron 10 operates not only on the battery 25 but also on power from a power supply connected via the USB cable 21. Figure 12 is a flowchart showing the process when the power supply is connected to the hair iron 10 via the USB cable 21. This process starts when the power supply is connected to the hair iron 10 via the USB cable 21 and the power of the hair iron 10 is turned on. Once the process starts, the control circuit of the hair iron 10 determines whether the output of the power supply is higher than a predetermined value (e.g., 36W) (S10). If it is determined that the output of the power supply is higher than the predetermined value (S10: YES), the control circuit of the hair iron 10 raises the temperature of the heating element 44 with power from the power supply (S11). On the other hand, if it is determined that the output of the power supply is lower than the predetermined value (S10: NO), the control circuit of the hair iron 10 determines whether the battery 25 is sufficiently charged (S12). If it is determined that the battery 25 is not sufficiently charged (S12: NO), the battery 25 is charged (S13). On the other hand, if it is determined that the battery 25 is sufficiently charged (S12: YES), the control circuit of the hair iron 10 raises the temperature of the heating element 44 using power from the battery 25 (S14). This flowchart ends when the power to the hair iron 10 is turned off.

[0058] The user removes the cap case 17, moves the operating part 35 of the locking member 33 to the unlocked position, and opens the hair iron 10. At this time, if the user tries to force the hair iron 10 open without moving the operating part 35 to the unlocked position, the first locking part 31 and the second locking part 32 will come into contact. This allows the user to realize that the hair iron 10 is locked. If the user still tries to force the hair iron 10 open, the contact force between the first locking part 31 and the second locking part 32 increases, and the locking member 33 moves to the unlocked position. This prevents damage to the base end 12 of the hair iron 10.

[0059] The user opens the hair iron 10 and then slides the switch 28 forward. The power turns on, and the hair iron 10 operates using power from the battery 25 or the power supply unit. If the battery 25 is not sufficiently charged, a low charge will be displayed on the display unit 14. The temperature of the heating element 44 rises to the set temperature relatively quickly (about 40 seconds) after the power is turned on.

[0060] The user places their hair between the pair of arms 13A and 13B. The plate 40 displaces to make close contact with the hair. Because the stroke of the plate 40 is large, the surface of the plate 40 easily makes close contact with the hair. Also, because the plate 40 displaces easily with little force, the user feels that the movement of their fingertips is easily transmitted to the plate 40.

[0061] The heat from the heating element 44 is efficiently transferred to the surface plate 42 by the carbon-containing heat conductive layer 43. The entire surface of the plate 40 heats up fairly uniformly, and the plate 40 applies heat uniformly to the hair. In addition, far-infrared rays are emitted from the carbon-containing heat conductive layer 43 to the hair. This allows the hair to be styled quickly while retaining moisture. Furthermore, the protrusions 19 of the comb-like portion 18 can improve the flow of the hair.

[0062] The heat from the heating element 44 is efficiently transferred to the surface plate 42 by the carbon-containing heat conductive layer 43, so it does not easily accumulate inside the housing 24. In addition, the heat inside the housing 24 is efficiently released to the outside by the comb-shaped portion 18. Therefore, the outer surface of the clamping portion 15 is prevented from becoming hot, so the user can grip the outer surface of the clamping portion 15 and move the hair iron 10.

[0063] After using the hair iron 10, the user slides the switch 28 to the power off position to turn off the power. Then, the user closes the hair iron 10 and moves the operating part 35 of the locking member 33 to the locked position. This causes the first locking part 31 and the second locking part 32 to face each other vertically, and the hair iron 10 is held in the locked state. After that, the cap case 17 is placed over it.

[0064] Even if the hair iron 10 is closed without moving the switch 28 to the power-off position, the switch 28 can be moved to the power-off position by placing the cap case 17 over it. Therefore, the hair iron 10 can be prevented from being left in the power-on position.

[0065] Next, the operation and effects of the embodiment configured as described above will be explained. The hair iron 10 of this embodiment is equipped with arm portions 13A and 13B extending from the base end portion 12. The arm portions 13A and 13B are equipped with a surface plate 42, a carbon-containing heat conductive layer 43 that extends along the back surface of the surface plate 42, and a heating element 44 positioned on the back side of the carbon-containing heat conductive layer 43. With this configuration, the heat from the heating element 44 is transmitted in the planar direction of the surface plate 42 by the carbon-containing heat conductive layer 43, making it easy to make the temperature of the surface plate 42 uniform. In addition, since far-infrared rays are generated by the carbon-containing heat conductive layer 43, it is possible to heat the hair to its deepest parts while suppressing thermal damage to the surface of the hair. Therefore, hairstyles can be styled well without damaging the hair.

[0066] Furthermore, the carbon-containing heat conductive layer 43 contains a graphite sheet. This configuration allows the carbon-containing heat conductive layer 43 to be made thinner, and the hair iron 10 to be made smaller. In addition, the surface temperature of the surface plate 42 can be made uniform, which makes it less likely for uneven protein denaturation of the hair to occur due to localized temperature increases.

[0067] Furthermore, the carbon-containing thermal conductive layer 43 is flexible. With this configuration, the carbon-containing thermal conductive layer 43 does not crack and can be easily handled.

[0068] Furthermore, the heating element 44 includes a film heater. This configuration allows the heating element 44 to be made thinner and the arm sections 13A and 13B to be miniaturized. The heat from the film heater spreads in the planar direction from the heater wire through the carbon-containing heat conductive layer 43. Therefore, the temperature of the surface plate 42 can be made uniform in the planar direction while miniaturizing the arm sections 13A and 13B.

[0069] Furthermore, the hair iron 10 has a battery compartment 26 that houses a battery 25, and operates using power from the battery 25. This configuration allows it to be used in places without an electrical outlet, making it easy to use as a portable device.

[0070] Furthermore, the hair iron 10 has a USB cable 21 port 22 and can be easily connected to a power supply via the USB cable 21. When the output of the power supply is higher than a predetermined value, it operates using power from the power supply, and when the output of the power supply is lower than a predetermined value, it operates using power from the battery 25. With this configuration, when a power supply with an output higher than a predetermined value is connected, it operates using power from the power supply, which extends the life of the battery 25, and it can be used even if the battery 25 is not charged. When a power supply with an output lower than a predetermined value is connected, it operates using power from the battery 25, which prevents performance degradation due to insufficient output.

[0071] <Other examples> The present invention is not limited to the embodiments described above and in the drawings, and the following embodiments, for example, are also included in the technical scope of the present invention. (1) In the above embodiment, the hair iron 10 is a straight iron that holds hair between a pair of arm portions 13A and 13B. However, the hair iron is not limited to this, and may also be a curling iron having a single cylindrical arm portion extending from a base end and a plate portion along the outer surface of the arm portion, with hair held between the arm portion and the plate portion. (2) In the above embodiment, the carbon-containing thermal conductive layer 43 is a flexible sheet. However, the carbon-containing thermal conductive layer may be a hard plate member or a carbon material that has been sprayed onto it. (3) In the above embodiment, the elastic member 41 is a conical coil spring. However, the elastic member is not limited to this, and can be any material that is easier to compress when the load from the front to the back is small than when the load is large. For example, it may be a block made of an elastic material, or it may be a combination of multiple spring members. When combining multiple elastic members, members with different elastic forces may be combined. The elastic member may also be rubber, a leaf spring, an uneven pitch coil spring, a tapered coil spring, etc. (4) In the above embodiment, the small diameter portion 41A of the conical coil spring is located on the plate 40 side, and the large diameter portion 41B is located on the housing 24 side. However, the small diameter portion of the conical coil spring may be located on the housing side and the large diameter portion on the plate side. (5) In the above embodiment, the elastic member 41 supports the plate 40 at two locations. However, the elastic member may support the plate at three or more locations. (6) In the above embodiment, the battery 25 is rechargeable. However, the battery may be, for example, a dry cell battery. (7) In the above embodiment, the dimensions of the plate 40 were illustrated. The dimensions of the plate can be changed as appropriate, and are not limited to these. [Explanation of symbols]

[0072] 10… Hair iron 12...Proximal end 13A, 13B... Arm section 21…USB cable 22…Socket 25...battery 26...Battery compartment 42…Surface plate 43…Carbon-containing thermal conductive layer 44… Heating element

Claims

1. It has an arm portion extending from the base end, The arm portion comprises a surface plate, a carbon-containing heat conductive layer extending along the back surface of the surface plate, a heating element positioned on the back side of the carbon-containing heat conductive layer, a heat conductive layer attached to the back side of the heating element, and a temperature sensor in contact with the back side of the heat conductive layer, in the hair iron.

2. The hair iron according to claim 1, wherein the carbon-containing heat conductive layer includes a graphite sheet.

3. The hair iron according to claim 1 or claim 2, wherein the carbon-containing heat conductive layer is flexible.

4. The hair iron according to any one of claims 1 to 3, wherein the heating element includes a film heater.

5. It has a battery compartment for housing batteries, A hair iron according to any one of claims 1 to 4, which operates using power from the aforementioned battery.

6. It has a USB cable port, It can be connected to a power supply via the aforementioned USB cable. When the output of the power supply is higher than a predetermined value, the device operates using power from the power supply. The hair iron according to claim 5, wherein when the output of the power supply is lower than a predetermined value, it operates using power from the battery.

7. It has a comb-like section with multiple protrusions, The hair iron according to any one of claims 1 to 6, wherein the plurality of protrusions are arranged in the direction in which the arm portion extends and are positioned along a part of the outer edge of the surface plate.

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