JP2000068040A - High frequency electromagnetic induction heating apparatus and road marking execution device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform fine adjustments of a tank heating temperature and make a heating coil part compact and light-weighted by supporting a heating coil in a housing separate from a control part and a power source part. SOLUTION: A heating coil 8, a supporting base 10 and a member of high magnetic permeability 15 are mounted in a housing 9, and the line of magnetic force is generated, when the high frequency current is supplied to a heating coil 8 from a control part mounted separately from the heating coil 8 and the housing 9, whereby the eddy- current is generated in the tank in the magnetic field. The tank is heated through eddy currents and the Joule heat due to the electric resistance of the tank 7. The heating temperature can be finely adjusted by adjusting the current value of the high frequency electric current or the heating power, so that a temperature in the tank can be easily and finely adjusted, by adjusting the current value of the heating power corresponding to the residual amount of the molten coating material in the tank. Accordingly, the nonconformities caused by the overheating of a lower part of the tank can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency electromagnetic induction heating apparatus provided with a pancake-shaped heating coil and a road marking apparatus using the same.

[0002]

2. Description of the Related Art A high-frequency electromagnetic induction heating device is employed in, for example, an electromagnetic cooker, and has a pancake-shaped heating coil, a control unit for controlling a high-frequency current supplied to the heating coil, and the like. The power supply unit is housed in one housing, and a cover plate on which a metal pot or the like is placed is provided on an upper surface of the housing facing the heating coil. Then, a high-frequency current is supplied from the control unit to the heating coil, an eddy current is generated in the pan bottom in the magnetic field, and the pan bottom is heated by Joule heat due to the eddy current and the electric resistance of the metal pan. is there.

[0003] In a paint heating and melting apparatus for road marking, a gas burner is provided on one side of a tank in which the paint is stored to heat the paint from the outside to melt the paint in the tank. .

[0004] A coating machine for road marking is shown in FIG.
, A tank (hopper) 100 for accommodating the melted paint supplied from a tank A of the paint heating and melting device, and a frame 10 on which the tank is mounted.
1, a lower portion of the tank 100 is provided with a discharge port, a shutter for opening and closing the discharge port, and a rotatable toothed rotor for injecting molten paint discharged by opening the discharge port downward. In addition, the frame 101 heats the lower side of the tank 100 from the outside to warm the molten paint in the tank 100, and rotates the gas burner 102 to prevent the molten paint from solidifying, and rotates the toothed rotor. Engine 103 is mounted.

[0005]

However, in the case where a heating coil, a control unit and a power supply unit are housed in one housing, such as a high-frequency electromagnetic induction heating device employed in an electromagnetic cooker or the like, a heating device is used. However, there is a problem that the size of the whole increases and the weight increases. Therefore, for example, in a case where the gas burner is used instead of the gas burner in a road marking construction device as shown in FIG. 10, there is a problem that it is difficult to attach the gas burner to a lower portion of the tank.

Further, in the case where a gas burner 102 is provided at one lower side of a tank, such as a paint heating / melting device and a coating machine in a conventional road marking construction device, a gas supply pipe connected to the gas burner 102 is provided. The heating temperature is adjusted by operating the on-off valve provided in the middle to change the gas supply amount to the gas burner 102, so that there is a problem that the heating temperature cannot be finely adjusted. In addition, since heating is performed only from one side of the lower part of the tank, the temperature of the lower part in the tank rises too much, which accelerates the deterioration of the paint inside, and the amount of paint in the tank decreases. In such a case, there is a problem that a portion of the upper portion of the tank where there is no paint is scorched.
In addition, this causes troubles such as the sedimentation of glass beads as a paint component. In addition, since the gas burner is heated by a direct fire, overheating of the molten paint, fire spread, and the like may occur, leaving a problem in disaster prevention.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a heating coil separated from a control section and a power supply section in a housing to support a heating coil portion to be mounted on a body to be heated. The heating coil can be reduced in size and weight, and the number of turns of the overheating coil and the distance between the coils can be reduced by winding the heating coil so that the surface to be opposed to the object to be heated has an oval pancake shape. Without increasing the pitch, the heating efficiency can be increased and the heating rate can be increased.In addition, by providing a pancake groove on the support surface for supporting the heating coil, the heating coil can be heated by electromagnetic induction. It is possible to prevent misalignment along the support surface, to enhance the heat insulating effect, and to provide a cover plate and a cover plate that cover the surface where the heating coil should face the object to be heated. By providing a heating element for the alternating magnetic field to be heated, the object to be heated other than iron can be satisfactorily heated, and by attaching a conduction heating element to the heating element for the alternating magnetic field, It is an object of the present invention to provide a high-frequency electromagnetic induction heating device capable of satisfactorily heating a body to be heated even when the shape of the body to be heated is a non-planar surface such as a curved surface or a spherical surface. Also, by supporting the pancake-shaped heating coil in a housing attached to the tank separately from the control unit and the power supply unit, the heating temperature for heating the tank can be easily finely adjusted, Moreover, it is an object of the present invention to provide a road marking construction device that can reduce the size and weight of the heating coil portion.

[0008]

According to a first aspect of the present invention, there is provided a high-frequency electromagnetic induction heating apparatus including a heating coil, a control unit for controlling a high-frequency current supplied to the heating coil, and a power supply unit for the control unit. In the induction heating device, the heating coil is supported in the housing separately from the control unit and the power supply unit.

According to the first aspect of the invention, since the heating coil is supported in the housing separately from the control unit and the power supply unit, the size of the heating coil attached to the object to be heated can be reduced.
Moreover, the weight can be reduced. Therefore, it can be easily attached to a heated body such as a paint tank in the road marking construction apparatus, and the strength burden of the heated body can be reduced.

A high-frequency electromagnetic induction heating apparatus according to a second aspect of the present invention is characterized in that the heating coil is wound in an oval pancake shape on the surface to be opposed to the object to be heated.

According to the second aspect of the present invention, the length of the heating area of the heating coil can be made longer than that of the circular shape without increasing the number of turns of the heating coil and the pitch between the coils. Even when the heated portion of the body is elongated in a rectangular shape, the heating coil can be attached such that the long side of the heating coil is along the longitudinal direction of the heated portion. Therefore, when heating the paint in the tank in which the molten paint or the like flows down in a direction crossing the longitudinal direction of the heated portion, the heating efficiency can be increased without wasting heat, and the heating rate can be increased. Can be faster.

In a high frequency electromagnetic induction heating apparatus according to a third aspect of the present invention, a pancake groove corresponding to the heating coil is provided on a supporting surface of the housing for supporting the heating coil. It is characterized by.

According to the third aspect of the present invention, the heating coil can be supported in a pancake groove corresponding to the pancake, so that when the heating coil is energized / cut off, the heating coil is electromagnetically induced. Can be prevented from being displaced along the supporting surface, and furthermore, the heat generated by the heating coil is transmitted to the protrusion between the adjacent grooves,
Escape to the back side of the support surface can be prevented well,
The heat insulation effect can be enhanced.

In a high frequency electromagnetic induction heating apparatus according to a fourth aspect of the present invention, the housing is provided with a cover plate for covering a surface on which the heating coil is to face the object to be heated, and a heating element for an alternating magnetic field which is superimposed on the cover plate. It is characterized by the following.

According to the fourth aspect of the present invention, since the eddy current due to the skin effect flows to the heating element for the alternating magnetic field to generate heat, the heating element is made of iron, Even in the case of a non-ferrous material such as copper, aluminum, heat-resistant glass, and porcelain, the object to be heated can be satisfactorily heated by a simple configuration in which an extra heating element for an alternating magnetic field is provided.

A high-frequency electromagnetic induction heating apparatus according to a fifth aspect of the present invention is characterized in that a conductive heating element capable of contacting the object to be heated is attached to the heating element.

According to the fifth aspect of the present invention, the heat generated by the heating element for the alternating magnetic field can be conducted to the conduction heating body and heated, so that the contact surface of the conduction heating body with the portion to be heated is heated. Is formed corresponding to the shape of the heated portion, the heated body can be satisfactorily heated even if the shape of the heated portion of the heated body is a non-planar surface such as a curved surface or a spherical surface.

According to a sixth aspect of the present invention, there is provided a road marking apparatus for heating a tank containing paint from outside thereof, the pan marking heating coil;
A control unit for controlling a high-frequency current supplied thereto, a power supply unit for the control unit, and a housing attached to the tank, wherein the heating coil is separately supported from the control unit and the power supply unit in the housing. It is characterized by having been done.

In the sixth invention, the heating temperature can be finely adjusted by adjusting the current value of the high-frequency current supplied to the heating coil, so that a gas burner is used as in the conventional example. In comparison, fine adjustment of the heating temperature can be easily performed. Therefore, it is preferable that the temperature inside the tank rises too much to accelerate the deterioration of the paint inside the tank, the remaining amount of paint becomes small and the upper part inside the tank becomes scorched, and the glass beads of the paint component settle. Can be prevented. In addition, since the paint in the tank is heated by using the heating coil, there is no possibility that the paint may overheat, spread, or the like as in the case of using a gas burner, thereby improving the disaster prevention.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. FIG. 1 is a perspective view showing a road marking construction apparatus of the present invention, and FIG. 2 is a vertical sectional side view showing the road marking construction apparatus. The road marking apparatus shown in FIGS. 1 and 2 is a coating machine, and is a metal tank (hopper) for storing molten paint supplied from a tank A containing paint in a paint heating and melting apparatus. 1 and a frame 2 on which it is mounted and a lower part of the tank 1 and one side of the tank
And a pair of high-frequency electromagnetic induction heating devices B, B for heating from both sides.

The tank 1 is formed to have a rectangular cross section, an upper portion thereof being open to the outside and serving as a supply port 1a, and a lower portion having a generally narrowed rectangular shape extending in the front-rear direction.
The outlet 1b is opened downward. In the vicinity of the discharge port 1b, a stator 3 extending downward from one side of the discharge port 1b is provided.
A shutter for opening and closing the shutter, and a peripheral surface having a toothed groove are separated from the stator 3 by a predetermined gap, and a rotation for ejecting the molten paint discharged downward by the opening operation of the shutter 4 downward. And a tooth-shaped rotor 5 capable of performing the following operations.

The frame 2 is formed in a rectangular frame shape. The tank 1 is mounted on one end in the longitudinal direction, and the engine 6 is mounted on the other end, and is provided on the output shaft of the engine 6. An endless belt 7 is hung between a driving wheel 6a and a rotating wheel 5a provided at one end of the toothed rotor 5, rotates the toothed rotor 5 by driving the engine 6, and is discharged downward from the outlet 1b. Molten paint can be sprayed downward.

Embodiment 1 FIG. 3 is a plan view of the high-frequency electromagnetic induction heating apparatus according to Embodiment 1 of the present invention, in which a cover plate of a single unit is removed, and FIG. 4 is an enlarged sectional view taken along line IV-IV of FIG. 5 is a sectional view taken along the line V-V in FIG. 3, and FIG. 6 is a sectional view taken along the line VI-VI in FIG. The high-frequency electromagnetic induction heating device B controls the heating coil 8 wound so that the surface facing the tank 1 has an elliptical pancake shape including an elliptical shape, and a high-frequency current supplied to the heating coil 8. , A power supply unit (not shown), and a rectangular box-shaped housing 9 for supporting the heating coil 8 separately from the control unit and the power supply unit. Have. The control section and the power supply section are housed in a housing member separate from the housing 9.

The heating coil 8 uses a litz wire in which 20 to 30 insulated copper wires of about 0.4 to 0.5 mm are twisted in order to flow a large high-frequency current, and the litz wire is impregnated with silicon resin. ing. The heating coil 8 is wound in the form of a close-row dense winding, and a pair of ends 8a and 8b are formed linearly outward in the radial direction. The one end 8a is overlapped with the back surface of the intermediate coil part as shown in FIG.

The housing 9 is made of a heat-resistant synthetic resin material, a high-resistance silicon steel material having a silicone resin coating layer, or the like.
A support base 10 having a core 0a and a core holding part 10b is provided. Further, the open portion of the housing 9 has a ceramic cover plate 11 and the end portions 8a and 8b of the heating coil 8.
Are provided with a pair of extraction recesses 9a and 9b for extracting the same to the outside. A sealant such as a silicone resin having excellent heat resistance and water resistance is filled between the end edge of the cover plate 11 and the housing 9.

At four corners of the housing 9, there are provided mounting holes 9c penetrating in the thickness direction, and the housing 9 is detachably mounted on the tank 1 by tightening mounting screws 12 inserted through the mounting holes 9c. I can do it.

The support base 10 is formed of a heat-resistant synthetic resin material. A pancake groove 13 having a pancake shape corresponding to the heating coil 8 is provided on the support surface 10a. The heating coil 8 is fitted into 13 and the heating coil 8 is bonded and fixed with a thermosetting adhesive. One end in the longitudinal direction of the pancake groove 13 communicates with a guide groove 14 formed deeper than the groove bottom in the middle part, and guides the end 8a of the heating coil 8 from the guide groove 14 to the take-out recess 9a. The other end is open to the side from the groove bottom so that the end 8b of the heating coil 8 is guided to the extraction recess 9b. The core holding portion 10b is provided in an annular shape on the back surface side of the support surface 10a, and a plurality of high magnetic permeability members 15 such as ferrite cores are held on the core holding portion 10b at a distance.

The high-frequency electromagnetic induction heating apparatus B constructed as described above includes a heating coil 8 and a support base 1 in a housing 9.
0, a high magnetic permeability member 15 is provided,
A cover plate 11 is attached to the open part of the unit to form a single unit. The unit alone is a mounting hole 9c of the housing 9.
The tank 1 can be easily mounted by inserting the mounting screws 12 into the holes and tightening the screw holes formed in the side wall of the tank 1. In addition, this attachment is performed such that the long side of the heating coil 8 is along the long side of the tank 1, in other words, crosses the discharge direction of the molten paint in the tank 1 (vertically downward in FIG. 1). It is mounting.

By supplying a high-frequency current to the heating coil 8 from a control unit provided separately from the heating coil 8 and the housing 9, magnetic lines of force are generated as shown in FIG. An eddy current is generated in the tank 1, and the tank 1 is heated by Joule heat due to the eddy current and the electric resistance of the tank 1.

Since the heating temperature can be finely adjusted by adjusting the current value of the high-frequency current or the heating power, the current value or the heating power is adjusted in accordance with the remaining amount of the molten paint in the tank 1. Thereby, the temperature in the tank 1 can be easily finely adjusted. Therefore, the temperature of the lower part in the tank 1 rises too much to promote the deterioration of the molten paint inside, or when the paint in the tank 1 becomes low, the upper part in the tank 1 becomes scorched or the glass beads of the paint component Settling can be favorably prevented. Further, since the paint in the tank 1 is heated by using the heating coil 8, there is no possibility that the paint may be overheated, spread, or the like as in the case of using a gas burner, thereby improving the disaster prevention.

Furthermore, by making the heating coil 8 oval, the length of the heating area of the heating coil 8 can be made longer than that of a circular coil without increasing the number of turns of the heating coil 8 and the pitch between the coils. The heating coil 8 formed in an oval shape is attached so that its long side crosses the discharge direction of the molten paint in the tank 1 as shown in FIG. The heating efficiency can be increased without increasing the temperature, and the heating rate can be increased.

Since the heating coil 8 is fitted and fixed in the corresponding pancake groove 13 which becomes a spiral, when the heating coil 8 is energized / cut off, the heating coil 8 is supported by electromagnetic induction. It is possible to satisfactorily prevent displacement or floating along the surface 10a, and furthermore, transfer the heat generated by the heating coil 8 to the protruding portion between the adjacent grooves, thereby forming the support surface 10a. Escape to the back side can be prevented well, and the heat insulating effect can be enhanced.

When a gas burner using a gas in a gas cylinder as a heat source is used as in the conventional example, a calorie of 1,030 kcal per hour can be obtained.
When a high-frequency electromagnetic induction heating device is used as in the present invention, by setting the heating power to 420 W, the same heat quantity as the gas burner can be obtained.

Second Embodiment FIG. 7 is a sectional view of a main part of a high-frequency electromagnetic induction heating apparatus according to a second embodiment. In the second embodiment, an iron heating element 16 for an alternating magnetic field is provided on the surface of a flat cover plate 11 provided at the open portion of the housing 9 so as to face the heating coil 8. Since other configurations and operations are the same as those of the first embodiment shown in FIGS. 1 to 6, the same reference numerals are given to the common components, and the detailed description and the operations are omitted.

The heating element 16 is made of a flat iron plate having a size corresponding to the opening of the housing 9, and is closely attached to the cover plate 11. Further, through-holes corresponding to the mounting holes 9c are provided at four corners of the heating element 16, and the mounting screw 12 is inserted through these through-holes so that the heating element 16 and the housing 9 are removed from the tank 1.
So that it can be attached to

In the second embodiment, the eddy current due to the skin effect flows through the heating element 16 for the alternating magnetic field, and the heating element 16 can be heated. Since about 90% of the total heat is generated in the surface layer having a depth of about 0.1 to 0.2 mm, no current flows through the heated object such as the tank 1 in contact with the surface of the heating element 16. It is. Therefore, not only when the material to be heated such as the tank 1 is made of iron, but also copper, aluminum,
Even in the case of a non-ferrous material such as heat-resistant glass or ceramics, the heating target such as the tank 1 can be satisfactorily heated by a simple configuration in which the heating element 16 for the alternating magnetic field is additionally provided.

Third Embodiment FIGS. 8 and 9 are cross-sectional views of essential parts showing a third embodiment of the high-frequency electromagnetic induction heating device. In the third embodiment, an iron heating element 16 for an alternating magnetic field is provided on the surface of a flat cover plate 11 provided on an open portion of the housing 9 so as to face the heating coil 8, and is superposed on the cover plate 11. Further, the heating element 1
6 is provided with a conductive heating element 17 in contact with the surface thereof, and the other configuration and operation are the same as those of the first embodiment shown in FIGS. The reference numerals are used, and the detailed description and operation are omitted.

The conduction heating element 17 shown in FIG. 8 has a first contact surface 17a and a curved second contact surface 17b that contact the surface of the heating element 16, and a pair of these is provided. In addition, these conduction heating elements 17 are provided with through holes corresponding to the mounting holes 9c and the through holes of the heating element 16,
When the mounting screw 12 is inserted into these through holes, the heating element 16 and the conduction heating element 17 are formed together with the housing 9.
Can be attached to the tank 1.

The conductive heating element 17 shown in FIG. 9 has a first contact surface 17a and a spherical second contact surface 17b which contact the surface of the heating element 16. The conduction heating element 17 is provided with through holes corresponding to the mounting holes 9c and the through holes of the heating element 16, and the mounting screws 12 are inserted through these through holes, so that the heating element 16 together with the housing 9 are provided. And the conductive heating element 17 can be attached to the tank 1.

In the third embodiment, since the heat generated by the heating element 16 for the alternating magnetic field can be conducted to the conduction heating body and heated, as shown in FIG. In the case of heating the curved surface of the heating body, FIG.
As shown in the figure, even when heating the spherical surface of the object to be heated such as the tank 1, the second contact surface 17b of the conduction heating element 17 can be brought into close contact with the object to be heated, and Can be heated.

The high-frequency electromagnetic induction heating device B according to the first to third embodiments can be used not only for a road marking construction device but also for other objects to be heated. Further, the road marking apparatus of the present invention is not only a coating machine configured to inject the molten paint in the tank 1, but also includes a tank A for melting the paint, The present invention may be applied to a paint heating and melting device configured to supply to the tank 1 of a coating machine.

[0042]

According to the high frequency electromagnetic induction heating apparatus of the first invention, the heating coil is separated from the control unit and the power supply unit and is supported in the housing. The weight can be reduced. Therefore, it can be easily attached to a heated body such as a paint tank in the road marking construction apparatus, and the strength burden of the heated body can be reduced.

According to the high frequency electromagnetic induction heating apparatus of the second invention, the length of the heating area of the heating coil is made longer than that of the circular shape without increasing the number of turns of the heating coil and the pitch between the coils. Therefore, even when the portion to be heated of the object to be heated is elongated in a rectangular shape, the heating coil can be attached such that the long side of the heating coil extends along the longitudinal direction of the portion to be heated. Therefore, when heating the paint in the tank in which the molten paint or the like flows down in a direction crossing the longitudinal direction of the heated portion, the heating efficiency can be increased without wasting heat, and the heating rate can be increased. Can be faster.

According to the high-frequency electromagnetic induction heating device of the third invention, the heating coil can be supported by the pancake groove corresponding to the pancake, so that when the heating coil is energized / cut off, It is possible to prevent the heating coil from being displaced along the supporting surface by electromagnetic induction, and to transmit the heat generated by the heating coil to the projecting portion between the adjacent grooves, and Escape to the back side can be prevented well, and the heat insulating effect can be enhanced.

According to the high-frequency electromagnetic induction heating apparatus of the fourth invention, the eddy current due to the skin effect flows through the heating element for the alternating magnetic field to cause the heating element to generate heat. In addition to the case where it is made of copper, aluminum, heat-resistant glass, and non-ferrous materials such as ceramics,
The object to be heated can be satisfactorily heated with a simple configuration in which an extra heating element for the alternating magnetic field is provided.

According to the high-frequency electromagnetic induction heating apparatus of the fifth invention, the heat generated by the heating element for the alternating magnetic field can be conducted to the conduction heating body and heated, so that the heating of the conduction heating body can be prevented. By forming the contact surface with the heating part corresponding to the shape of the heated part, the heated body can be satisfactorily heated even if the heated part has a non-planar surface such as a curved surface or a spherical surface. be able to.

According to the road marking apparatus of the sixth invention, the heating temperature can be finely adjusted by adjusting the current value of the high-frequency current supplied to the heating coil.
Fine adjustment of the heating temperature can be easily performed as compared with the conventional example using a gas burner. Therefore, it is preferable that the temperature inside the tank rises too much to accelerate the deterioration of the paint inside the tank, the remaining amount of paint becomes small and the upper part inside the tank becomes scorched, and the glass beads of the paint component settle. Can be prevented. In addition, since the paint in the tank is heated by using the heating coil, there is no possibility that the paint may overheat, spread, or the like as in the case of using a gas burner, thereby improving the disaster prevention.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a road marking apparatus according to the present invention.

FIG. 2 is a longitudinal sectional side view showing a road marking apparatus according to the present invention.

FIG. 3 is a plan view of the high-frequency electromagnetic induction heating device according to the first embodiment of the present invention in a state where a cover plate showing a single unit is removed.

FIG. 4 is an enlarged sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a sectional view taken along line VV of FIG. 3;

FIG. 6 is a sectional view taken along line VI-VI of FIG. 3;

FIG. 7 is a cross-sectional view showing Embodiment 2 of the high-frequency electromagnetic induction heating device according to the present invention.

FIG. 8 is a sectional view showing Embodiment 3 of the high-frequency electromagnetic induction heating device according to the present invention.

FIG. 9 is a sectional view showing Embodiment 3 of the high-frequency electromagnetic induction heating device according to the present invention.

FIG. 10 is a perspective view showing a conventional road marking construction apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank 8 Heating coil 9 Housing 10a Support surface 11 Cover plate 13 Pancake groove 16 Heating body 17 Conduction heating body B High frequency electromagnetic induction heating device

Claims (6)

[Claims] 1. A high-frequency electromagnetic induction heating apparatus comprising a heating coil, a control unit for controlling a high-frequency current supplied to the heating coil, and a power supply unit for the heating coil, wherein the heating coil includes a control unit in a housing. And a high-frequency electromagnetic induction heating device, which is supported separately from the power supply unit. 2. A surface of the heating coil facing the object to be heated is wound into an oblong pancake shape.
The high-frequency electromagnetic induction heating device as described in the above. 3. The high-frequency electromagnetic induction according to claim 1, wherein the housing has a pancake groove formed in a pancake shape corresponding to the heating coil on a support surface for supporting the heating coil. Heating equipment. 4. The housing according to claim 1, further comprising: a cover plate for covering a surface of the heating coil facing the object to be heated, and a heating element for an alternating magnetic field superposed on the cover plate. A high-frequency electromagnetic induction heating device according to any one of the above. 5. The high-frequency electromagnetic induction heating device according to claim 4, wherein a conductive heating element capable of contacting the object to be heated is attached to the heating element. 6. A road marking apparatus for heating a tank containing paint from outside thereof, a pancake-shaped heating coil, a control unit for controlling a high-frequency current supplied thereto, and a control unit for controlling the high-frequency current supplied to the heating coil. A road marking construction device, comprising: a power supply unit; and a housing attached to the tank, wherein the heating coil is supported in the housing separately from the control unit and the power supply unit.