JP7491835B2 - Hair clamping device - Google Patents

Description

The present invention relates to a hair clamping device.

Hair clamping devices are widely used in beauty salons, homes, etc. Patent Document 1 discloses an example of a hair clamping device, a so-called hair iron, that can set hair by clamping and heating the hair between a pair of plates.

JP 2007-312807 A

In such hair clamping devices, there is a demand for further improvement in the operability for the user when clamping and moving the hair, as well as a reduction in the burden on the hair, or rather a positive effect on the hair.

In consideration of the above circumstances, the present invention aims to provide a hair clamping device that is easy to operate, reduces the burden on the hair, and can actually have a positive effect on the hair.

According to one aspect of the present invention, a hair clamping device is provided. The hair clamping device includes a housing. The housing includes a pair of plates inside that can come into contact with or separate from each other in response to a user's gripping and releasing action on an operating point. At least one of the pair of plates is configured to clamp the hair in response to the user's gripping action and to allow ions to flow in and out of the hair by passing electricity through it. The position or orientation of the plate is configured to be variable relative to the housing.

This type of feature improves operability, reduces stress on the hair, and actually has a positive effect on the hair.

FIG. 2 is a plan view showing the appearance of the hair clamping device 1. FIG. 2 is a front view showing the appearance of the hair clamping device 1. FIG. 2 is a perspective view of the hair clamping device 1, particularly showing the first plate 21 provided on the inner side 11b of the housing 11. 2 is a plan view showing the state of the inner side 11b of the housing 11. FIG. FIG. 2 is a perspective view of the hair clamping device 1, particularly showing the second plate 22 provided on the inner side 12b of the housing 12. 2 is a plan view showing an aspect of the inner side 12b of the housing 12. FIG. 2 is a block diagram showing functional members included in the plate 2. FIG. 2 is a block diagram showing an electrical configuration of the hair clamping device 1. FIG. 13 is a diagram showing an embodiment in which a first conductive portion 31 serving as an electrode is provided on a plate 2. FIG. 1 is a diagram showing an embodiment in which a first conductive portion 31 and a second conductive portion 32 that are electrodes are provided on a plate 2. FIG. FIG. 13 is a diagram showing an embodiment in which a first conductive portion 31, which is an electrode, is provided on a first plate 21, and a second conductive portion 32 is provided on a second plate 22.

The following describes embodiments of the present invention with reference to the drawings. The various features shown in the following embodiments can be combined with each other.

The program for realizing the software appearing in this embodiment may be provided as a non-transitory computer-readable recording medium, or may be provided so as to be downloadable from an external server, or may be provided so that the program is started on an external computer and its functions are realized on a client terminal (so-called cloud computing).

In this embodiment, a "unit" may include, for example, a combination of hardware resources implemented by a circuit in the broad sense and software information processing that can be specifically realized by these hardware resources. In addition, this embodiment handles various types of information, which may be represented, for example, by physical values of signal values representing voltage and current, high and low signal values as a binary bit collection consisting of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculations may be performed on a circuit in the broad sense.

In the broad sense, a circuit is a circuit realized by at least appropriately combining a circuit, circuitry, a processor, and memory. In other words, it includes application specific integrated circuits (ASICs), programmable logic devices (e.g., simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs)).

1. Basic Configuration In this section, the basic configuration of the hair clamping device 1 according to this embodiment will be described. By clamping and moving hair with this hair clamping device 1, a user such as a hairdresser can perform beauty treatments such as adjusting the hairstyle of the subject, treatment, straightening a perm, and hair straightening. Alternatively, the subject himself may use the hair clamping device 1 to clamp his own hair and perform these beauty treatments. In particular, this embodiment will be described assuming that a treatment is performed using the hair clamping device 1 to penetrate the drug after applying a drug to the subject's hair.

(Housings 11, 12)
Fig. 1 is a plan view showing the appearance of the hair clamping device 1. Fig. 2 is a front view showing the appearance of the hair clamping device 1. As shown in Fig. 1 and Fig. 2, the hair clamping device 1 includes housings 11 and 12 and a hinge 13. The hair clamping device 1 is broadly divided into an operation portion 14 and an action portion 15.

The housings 11 and 12 are each formed as a long thin plate. Also, for safety reasons, they have a rounded shape overall, but this is just one example and is not intended to be limiting.

The housing 11 is configured to rotate relative to the housing 12, with the center of the hinge 13 as a fulcrum. When using the hair clamping device 1, the user grasps or releases the operation point 14 on the left side of the outsides 11a, 12a of the housings 11, 12 in the figure. This causes the action point 15 on the right side of the outsides 11a, 12a of the housings 11, 12 in the figure to open and close, with the center of the hinge 13 as a fulcrum. This action allows the hair clamping device 1 to function as a hair clamping device such as a hair iron.

Incidentally, in Figures 1 and 2, the housing 11 and the housing 12 are shown in close proximity to each other, but if the user does not understand the operation location 14, it is preferable that the housings 11 and 12 are biased by a spring (not shown) or the like so that they move away from each other.

(Plate 2)
The housings 11 and 12 are provided on their inner sides 11b and 12b with a pair of plates 2 that can come into contact with or separate from each other in response to a user's grasping and opening action on the operation location 14. In FIG. 2, the pair of plates 2 is composed of a first plate 21 provided on the housing 11 and a second plate 22 provided on the housing 12.

Figure 3 is a perspective view of the hair clamping device 1, particularly showing the first plate 21 provided on the inner side 11b of the housing 11. Figure 4 is a plan view showing the state of the inner side 11b of the housing 11. As shown in Figures 3 and 4, the first plate 21 is provided on the inner side 11b of the housing 11 so as to occupy most of the action point 15. In addition, the first plate 21 is formed in a rectangular shape so that the direction X, which is the longitudinal direction of the housing 11, is the longitudinal direction of the first plate 21 itself.

Figure 5 is a perspective view of the hair clamping device 1, particularly showing the second plate 22 provided on the inner side 12b of the housing 12. Figure 6 is a plan view showing the state of the inner side 12b of the housing 12. As shown in Figures 5 and 6, two second plates 22 are provided on the inner side 12b of the housing 12 so as to occupy most of both sides of the action point 15. Furthermore, the two second plates 22 are formed in a rectangular shape so that the direction X, which is the longitudinal direction of the housing 12, is the longitudinal direction of each second plate 22. A recess 16 is formed between the two second plates 22. The recess 16 will be described in detail later.

At least one of the pair of plates 2 consisting of the first plate 21 and the second plate 22 is configured to clamp the hair when grasped by the user, and to heat the hair and introduce ions into and out of the hair by passing electricity through it. Heating and electricity passing through it will be described in detail later.

Here, preferably, the plate 2 is configured so that its position or orientation can be changed with respect to the housings 11 and 12. In other words, the plate 2 may be configured so as to have a movable area. More specifically, the plate 2 may be configured so that its position or orientation can be changed in two axes, for example, in the direction X and the direction Y. Referring to FIG. 4, the first plate 21 may be implemented so that it rotates or tilts in the direction of the paper, for example, with the side SX or the axis AX as an approximate pivot (or approximate fulcrum in some cases). The rotation angle or tilt angle is preferably a small angle, such as 10 degrees or less. Similarly, the plate 21 may be implemented so that it rotates or tilts in the direction of the paper, with the side SY or the axis AY as an approximate pivot (or approximate fulcrum in some cases). Alternatively, the first plate 21 may be configured so that it can be translated in a small range in two axial directions, the direction X and the direction Y.

On the other hand, referring to FIG. 6, the two second plates 22 may be configured to rotate or tilt in the direction of the paper, for example with sides SX1, SX2 or axes AX1, AX2 acting as approximate pivots (or approximate fulcrums in some cases). The rotation angle or tilt angle is preferably a small angle, such as 10 degrees or less. Similarly, the two second plates 22 may be configured to rotate in the direction of the paper, with side SY or axis AY acting as approximate pivot (or approximate fulcrum in some cases). Alternatively, the two second plates 22 may be configured to be able to translate in a small range in two axial directions, directions X and Y.

The internal structure for displacing the position or orientation in this manner is not particularly limited; for example, at least three of the four vertices of the rectangular plate 2 may be fixed with elastic members such as springs or elastic members such as rubber. This allows for simultaneous realization of two-axis translational displacement and rotational or tilt displacement.

By the way, it is preferable that the angle of rotation or tilt displacement is 10 degrees or less. Specifically, this angle is, for example, 10, 9.7, 9.4, 9.1, 8.8, 8.5, 8.2, 7.9, 7.6, 7.3, 7, 6.7, 6.4, 6.1, 5.8, 5.5, 5.2, 4.9, 4.6, 4.3, 4, 3.7, 3.4, 3.1, 2.8, 2.5, 2.2, 1.9, 1.6, 1.3, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 degrees, and may be within a range between any two of the numerical values exemplified here.

The distance of translational displacement is preferably 0.5 times or less the length of the direction Y, which is the short side direction of the plate 2. This ratio is, for example, 0.5, 0.4, 0.3, 0.2, 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01, 0.009, 0.008, 0.007, 0.006, 0.005, 0.004, 0.003, 0.002, 0.001, and may be within a range between any two of the numerical values exemplified here.

In this way, the position or orientation of plate 2 can be changed on two axes, improving the user's sense of operation when clamping and moving hair. In addition, the structure is designed so that excessive force from the user is not transmitted by the displacement of plate 2, preventing the subject's hair from being accidentally pulled out. As a result, the subject's pain is also alleviated.

As mentioned above, a recess 16 is provided on the inner side 12b of the housing 12. Here, one long recess 16 is formed at a position sandwiched between two second plates 22. In other words, the recess 16 is formed along the direction X, which is the longitudinal direction of the pair of plates 2. Of course, the shape and number are not limited to this.

Hair clamping device Moisture is contained inside the cuticle of hair. However, when the hair is heated while being clamped by the plates 2, it can cause a sudden evaporation of moisture in the hair, known as a steam explosion. In particular, because the cuticle on the surface of the hair is opened by heating, it is possible that the necessary moisture in the hair can evaporate excessively, and in some cases, nutrients can also be lost. Furthermore, if the hair is clamped by the plates 2 with a wet surface, such a steam explosion can cause damage to the hair. In this embodiment, the recess 16 is provided on the inner side 12b to reduce the degree of sealing and suppress the steam explosion.

Figure 7 is a block diagram showing the functional members included in the plate 2. As shown in Figure 7, the plate 2 is equipped with a heater 23. When the power supply of the hair clamping device 1 is on, the heater 23 can convert electrical energy into Joule heat to heat the hair. The temperature of the plate 2 can be, for example, 40 to 230 degrees, and it is preferable that the temperature can be set to an appropriate temperature for each treatment. In particular, the temperature of the plate 2 is preferably about 50 to 70 degrees. Most preferably, the temperature of the plate 2 is 60 degrees. Specifically, the temperature of the plate 2 can be, for example, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, or 70 degrees, or may be within a range between any two of the numerical values exemplified here. When a treatment agent is applied to the hair, the plate 2 heated to about 60 degrees is applied to the hair, thereby enhancing the penetration effect of the agent.

7, at least one of the pair of plates 2 includes a light-emitting element 24. The light-emitting element 24 is, for example, a red or infrared light-emitting diode. Preferably, the wavelength of the light emitted by the light-emitting element 24 is 590 to 780 nm, and more preferably, 600 to 650 nm. Specifically, the wavelength of the light is, for example, 590, 595, 600, 605, 610, 615, 620, 625, 630, 635, 640, 645, 650, 655, 660, 665, 670, 675, 680, 685, 690, 695, 700, 705, 710, 715, 720, 725, 730, 735, 740, 745, 750, 755, 760, 765, 770, 775, or 780 nm, or may be within a range between any two of the values exemplified here. In this way, by irradiating the hair with light having a specific wavelength, rather than just heating it, the cuticle of the hair can be effectively opened.

Furthermore, as shown in FIG. 7, the plate 2 is provided with a first conductive portion 31, which is an example of a conductive portion 3. This will be described further below.

(Conductive portion 3)
The hair clamping device 1 includes a first conductive part 31, which is an example of a conductive part 3, and a second conductive part 32. The first conductive part 31 is provided on one of the pair of plates 2, for example, the first plate 21. The hair clamping device 1 is configured to perform ion inflow and outflow by passing electricity between the first conductive part 31 and the second conductive part 32. In this manner, the hair clamping device 1 is endowed with an ion inflow and outflow function, and a better beauty effect can be achieved on the hair. In particular, it is preferable to perform ion inflow and outflow in a state heated to about 60 degrees by the heater 23 described above.

The form of the conductive part 3 is not particularly limited, but preferably the first conductive part 31 is a coating on the plate 2. Examples of conductive coatings include coatings made of conductive urethane, fluororesin, etc., but preferably a material with good slipperiness such as a ceramic coating, Teflon coating, or silicone coating is used. In other words, the plate 2 is preferably coated with silicone so that it functions as the first conductive part 31. By coating the first conductive part 31 with conductivity, the entire plate 2 is made conductive, and ions can be introduced and removed from the entire hair when it is clamped. Furthermore, the lack of electrodes also improves design.

The second conductive part 32 may be provided on the plate 2 in the same manner as the first conductive part 31, but preferably, as shown in Figs. 2, 3 and 5, the second conductive part 32 is provided on at least a part of the housings 11, 12, for example, near the hinge 13 including the operation point 14, and configured to be able to come into contact with the user's fingers. Such a second conductive part 32 is configured as an electrode and may be called a hand electrode. In particular, if the user is the subject himself, the use of a hand electrode allows ions to be introduced and removed between the hand and the hair, providing a cosmetic effect not only to the hair but also to the subject's body.

2. Electrical Configuration In this section, the electrical configuration of the hair clamping device 1 will be described. First, as shown in Fig. 1 and Fig. 2, the hair clamping device 1 has a cable 5, and is supplied with power via the cable 5. Fig. 8 is a block diagram showing the electrical configuration of the hair clamping device 1. As shown in Fig. 8, the hair clamping device 1 has a communication unit 41, a storage unit 42, and a control unit 43, and these components are connected via a communication bus 40.

The communication unit 41 can execute information communication between the hair clamping device 1 and an external device. This allows the firmware version of the hair clamping device 1 to be updated and functions to be linked with a user's smartphone or the like. The storage unit 42 stores various information defined by the above description. This can be implemented, for example, as a volatile or non-volatile memory that stores various programs related to the hair clamping device 1 executed by the control unit 43 or temporarily required information (arguments, arrays, etc.) related to the program calculations. It may also be a combination of these. The control unit 43 processes and controls the overall operation related to the hair clamping device 1. The control unit 43 is, for example, a microcomputer or a CPU (not shown). The control unit 43 realizes various functions provided in the hair clamping device 1 by reading out a predetermined program stored in the storage unit 42.

The function to be executed by the hair clamping device 1 may be automatically selected by the control unit 43, or may be selected by the user using a switch (not shown) or the like. Such a function may be heating by the heater 23, irradiation of far-infrared light by the light-emitting element 24, or introduction and discharge of ions by the conductive part 3.

More specifically, the hair clamping device 1 is configured such that the control unit 43 controls the manner of current flow related to the introduction and withdrawal of ions. In this manner, the hair clamping device 1 can introduce and withdraw appropriate ions according to the condition of the hair, etc. Preferably, the control unit 43 may execute current flow with polarity switched at a predetermined timing or randomly. In this manner, static electricity that damages hair can be removed. More preferably, the control unit 43 may alternate the polarity, or may switch in a biased manner. For example, by biasing the polarity to two positive pulses and one negative pulse, the effect of introducing and withdrawing ions can be increased while removing static electricity.

According to this embodiment, it is possible to provide a hair clamping device 1 that improves operability, reduces the burden on the hair, and can actually have a positive effect on the hair.

3. Others The hair clamping device 1 according to the present embodiment may be implemented in the following manner.

(1) Instead of a conductive coating, the first conductive portion 31 may be an electrode. More specifically, the first conductive portion 31 may be employed as an electrode provided on the plate 2. Figure 9 is a diagram showing an embodiment in which the first conductive portion 31, which is an electrode, is provided on the plate 2. As shown in Figure 9, the first conductive portion 31 is formed in a rectangular shape in the center of the plate 2. This embodiment also makes it possible to introduce and extract ions into and from the subject's hair. In particular, the first conductive portion 31 may be formed in a convex shape protruding from the plate 2. The height of the convex shape is preferably 0.01 to 5 mm, and specifically, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1. 9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5 mm, and may be within a range between any two of the numerical values exemplified here. By making the plate 2 have such a convex shape, the first conductive part 31 can be more reliably in contact with the hair when the plate 2 comes into contact with the hair, so that ions can be introduced and removed more effectively.

(2) The second conductive portion 32 may also be an electrode. FIG. 10 is a diagram showing an embodiment in which the first conductive portion 31 and the second conductive portion 32, which are electrodes, are provided on the plate 2. More specifically, the second conductive portion 32 is provided on one of the pair of plates 2 together with the first conductive portion 31. The first conductive portion 31 and the second conductive portion 32 are formed on both ends of the plate 2. As shown in FIG. 10, the first conductive portion 31 and the second conductive portion 32 are formed in a rectangular shape on both ends of the plate 2. This embodiment also allows ions to be introduced into and extracted from the subject's hair. In particular, the first conductive portion 31 and the second conductive portion 32 may be formed lower than the plate 2. Alternatively, the first conductive portion 31 and the second conductive portion 32 may have a curved surface that curves outward. These embodiments allow the hair to come into contact with the conductive portion 3 more naturally due to the slight tilt when the user moves the hair clamping device 1. This reduces the pain caused by pinching the hair with too much force, while still allowing ions to flow in and out.

(3) When the first conductive portion 31 and the second electrode portion are electrodes, the second conductive portion 32 may be provided on the other of the pair of plates 2, for example, the second plate 22. FIG. 11 is a diagram showing an embodiment in which the first conductive portion 31, which is an electrode, is provided on the first plate 21, and the second conductive portion 32 is provided on the second plate 22. As shown in FIG. 11, the first conductive portion 31 is formed in a rectangular shape in the center of the first plate 21, and the second conductive portion 32 is formed in a rectangular shape in the center of the second plate 22. This embodiment also allows ions to be introduced into and extracted from the subject's hair. In particular, efficient ion introduction and extraction can be achieved by clamping from both sides to introduce and extract ions.

(4) A plurality of recesses different from recesses 16 may be formed along direction Y, which is the short side direction of the pair of plates 2. With this configuration, when moving the hair clamping device 1 while clamping the hair, a comb-like sensation can be provided to the user, improving operability. Similarly, a comb portion (not shown) having uneven portions made of silicon or metal may be provided at the ends of the inner sides 11b and 12b. This allows the user to brush the subject's hair for a finishing shine simply by using the hair clamping device 1.

(5) In this embodiment, both of the pair of plates 2 are configured to be variable in position or orientation along two axes relative to the housings 11, 12. Alternatively, either one of the pair of plates 2 may be configured to be variable in position or orientation along two axes relative to either one of the housings 11, 12. Furthermore, the position or orientation of either or both of the pair of plates 2 may be variable along one axis, for example, in the X direction or the Y direction.

(6) In this embodiment, the hair is clamped and heated by the plate 2, but this is not limiting and other treatments that have a favorable effect on the hair, such as ultrasonic treatment, may also be performed.

(7) In this embodiment, the second conductive portion 32, called the hand electrode, is provided at the operation location 14, but this is also one example, and it may be configured in a part of the housings 11 and 12. It is preferable to configure it in a location that is likely to be touched by fingers during processing, depending on the shape of the housing.

(8) Although the first conductive portion 31 has been shown to have a rectangular shape, it may also be circular or polygonal. For example, if the first conductive portion 31 is configured as an oval, the degree of treatment can be reduced at the upper and lower ends of the first conductive portion 31 and increased at the center where a large amount of hair overlaps, thereby increasing the degree of design freedom.

(9) The surfaces of the first conductive portion 31 and the second conductive portion 32 may be provided with irregularities to increase the contact area with the hair.

Furthermore, it may be provided in the following aspects:
The hair clamping device further comprises a first conductive portion and a second conductive portion, the first conductive portion being provided on one of the pair of plates and configured to conduct the ions in and out by passing electricity between the first conductive portion and the second conductive portion.
In the hair clamping device, the first conductive portion is a coating on a pair of plates.
In the hair clamping device, the second conductive portion is provided on at least a part of the housing and configured to be contactable with the user's fingers.
In the hair clamping device, the first conductive portion and the second conductive portion are electrodes, the second conductive portion is provided on one of the pair of plates together with the first conductive portion, and the first conductive portion and the second conductive portion are formed on both ends of the plates.
In the hair clamping device, the first conductive portion and the second conductive portion are electrodes, and the second conductive portion is provided on the other of the pair of plates.
In the hair clamping device, at least one of the pair of plates is provided with a light emitting element.
In the hair clamping device, a recess is provided on the inside of the housing.
In the hair clamping device, the recesses are formed along the longitudinal direction of the pair of plates.
In the hair clamping device, the pair of plates are configured so that the position or orientation can be changed along two axes.
The hair clamping device further comprises a control unit, the control unit being configured to control the manner of current flow related to the inflow and outflow of the ions.
In the hair clamping device, the control unit executes energization with polarity switched at a predetermined timing or randomly.
Of course, this is not the case.

Finally, although various embodiments of the present invention have been described, these are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and their modifications are within the scope and spirit of the invention, and are included in the scope of the invention and its equivalents as set forth in the claims.

1: Hair clamping device 11: Housing 11a: Outside 11b: Inside 12: Housing 12a: Outside 12b: Inside 13: Hinge 14: Operation point 15: Action point 16: Recess 2: Plate 21: First plate 22: Second plate 23: Heater 24: Light-emitting element 3: Conductive part 31: First conductive part 32: Second conductive part 40: Communication bus 41: Communication part 42: Memory part 43: Control part 5: Cable AX: Axis AX1: Axis AX2: Axis AY: Axis SX: Side SX1: Side SX2: Side SY: Side X: Direction Y: Direction

Claims (8)

A hair clamping device, comprising:
The device includes a housing, a first conductive part, and a second conductive part,
The housing includes a pair of plates on the inside thereof that can come into contact with or separate from each other in response to a user's gripping and releasing action on an operating portion,
The pair of plates are formed in a rectangular shape that can define a longitudinal direction and a lateral direction,
At least one of the pair of plates is configured so that a position or an orientation of the plate is variable with respect to the housing;
The first conductive portion and the second conductive portion are
an electrode provided at each end in the short-side direction of one of the pair of plates,
a curved surface that extends along the plate in the longitudinal direction and curves outwardly in the lateral direction so as to move away from the other of the pair of plates ,
When the user grasps the hair, the hair comes into contact with the curved surface and electricity is passed through the hair. The hair clamping device according to claim 1,
At least one of the pair of plates is provided with a light emitting element. The hair clamping device according to claim 1 or 2,
A recess is provided on the inside of the housing. The hair clamping device according to claim 3,
The recesses are formed along the longitudinal direction of the pair of plates. The hair clamping device according to any one of claims 1 to 4,
The pair of plates is configured so that the position or orientation can be changed along two axes. The hair clamping device according to any one of claims 1 to 5,
At least one of the pair of plates is configured to clamp the hair by the user's grasping action and to be able to introduce ions into and out of the hair by passing an electric current through the hair. The hair clamping device according to claim 6,
A control unit is further provided.
The control unit is configured to control a mode of current flow related to the inflow and outflow of the ions. The hair clamping device according to claim 7,
The control unit executes energization with polarity interchanged at a predetermined timing or randomly.