JP2010129422A - Electromagnetic induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic induction heating device of high power, high efficiency, and capable of heating. <P>SOLUTION: In the electromagnetic induction heating device heating a heating roller 5 with electromagnetic induction heating by an excitation coil 7, the excitation coil 7 has a wire rod 13 made of a litz wire of a cross-section flat shape, is arranged within an angle range θ of 90 degrees or more and 210 degrees or less along an outer periphery face 6 of the heating roller 5, with an opposed area increased of the outer periphery face 6 of the heating roller 5 and the wire rod 13 of the excitation coil 7, with the number of turns of the excitation coil 7 decreased, and with an inductance of the excitation coil 7 lowered, so that magnetic bonding of the excitation coil 7 and the heating roller 5 is strengthened and high-frequency drive of the electromagnetic induction heating device is made possible to achieve high power and high-efficiency heating of the heating roller 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic induction heating device used for electromagnetic induction heating.

2. Description of the Related Art Conventionally, in a copying machine or the like, there is an electromagnetic induction type heating device as a heating unit when transferring an image of toner and heating and fixing to form an image (Patent Document 1 and Patent Document 2).
JP 2008-40176 A JP 2004-246353 A

  However, in the electromagnetic induction heating devices of Patent Document 1 and Patent Document 2, in order to heat with high power and high efficiency when performing electromagnetic induction heating, electromagnetic induction heating with high frequency driving is necessary, and high frequency driving is performed. In order to do this, it is necessary to reduce the inductance of the coil, that is, to reduce the number of turns. There was a possibility of causing destruction.

  The present invention has been made in view of the above problems, and an object thereof is to provide an electromagnetic induction heating apparatus capable of heating with high power and high efficiency.

  The electromagnetic induction heating device according to claim 1 is an electromagnetic induction heating device that heats a heating element by electromagnetic induction heating using a coil, wherein the coil is a litz wire having a flat cross-section, and the heating element Along the outer peripheral surface, it is arranged in an angle range of 90 degrees or more and 210 degrees or less.

  According to the first aspect of the present invention, the coil wire is made of a litz wire having a flat cross section, thereby increasing the facing area between the heating element and the coil wire, reducing the number of turns of the coil, By reducing the inductance, the magnetic coupling between the coil and the heating element is strengthened, and the electromagnetic induction heating device can be driven at a high frequency to enable high power and high efficiency heating.

  Hereinafter, preferred embodiments of an electromagnetic induction heating device according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a configuration of a fixing device including an electromagnetic induction heating device according to the present invention.

  The fixing machine 1 of this embodiment is used for a copying machine or the like, and includes an induction heating unit 2, a fixing unit unit 3, and a heating control circuit 4 that controls the induction heating unit 2. Here, the induction heating unit 2 and the fixing unit unit 3 constitute an electromagnetic induction heating device.

  FIG. 2 is a cross-sectional view showing the vicinity of the induction heating unit 2 and the fixing unit unit 3.

  The heating roller 5 provided in the fixing unit 3 is a rotatable cylindrical metal heating element for fixing toner to paper, which is a heat generating body, and is a hollow cylinder made of a magnetic metal such as iron or stainless steel. Composed.

  The induction heating unit 2 is an excitation coil unit that heats along the outer peripheral surface 6 of the heating roller 5 by electromagnetic induction, and the excitation coil 7 and the outer peripheral surface 6 of the heating roller 5 serving as the heating coil 5 are substantially constant. A coil support body 9 as a support body having a coil support surface 8 as a support portion held at a distance and a ferrite core (not shown) supported by the coil support body 9 are provided.

  The coil support 9 is disposed close to the outer peripheral surface 6 of the heating roller 5 and is formed by being curved in a substantially concentric arc shape with the heating roller 5 so as to have a curvature substantially equal to the outer periphery of the heating roller 5 according to the heating roller 5. A coil support surface 8 is provided as a support-side arcuate surface. At both ends in the arc direction of the coil support surface 8, a pair of standing wall portions 10, 11 formed to project outward in the radial direction of the heating roller 5 are provided. Further, a rib 12 for holding the exciting coil 7 is provided on the coil support surface 8 so as to protrude. As shown in FIG. 2, the exciting coil 7 is formed by winding a wire 13 around the rib 12 a plurality of times. Is a wound bundle.

  The wire 13 has a cross-sectional circular litz wire having a diameter D1 of about 2 mm as shown in FIG. 4 and has a width D2 in the X direction, which is the longitudinal direction of the cross-sectional portion along the radial direction, by pressing or the like. 4 mm, a cross section in which the width D3 in the Y direction, which is the short direction perpendicular to the X direction, is about 1 mm, and the dimensional ratio of the major axis direction (X direction) to the minor axis direction (Y direction) is 4: 1. It is formed into a flat mold (see FIG. 3).

  Here, in the first insulating coating 14 made of an insulating material such as resin or glass, which is the outer skin of the wire 13, a plurality of strands 15 made of copper wire or the like having a diameter D1 of about 0.15 mm (this embodiment) In this case, it is assumed that it is housed in a twisted state. Further, it is assumed that a second insulating film 16 made of an insulating material such as resin or glass is formed on the surface of the strand 15.

  The exciting coil 7 is densely formed in an oval shape on the coil support surface 8 while facing and closely contacting a narrow portion 17 which is a narrow and narrow surface (parallel to the minor axis direction (Y direction) of the wire 13. The flat portion 18, which is a wide surface parallel to the major axis direction (X direction) of the wire 13, is brought into contact with the coil support surface 8, so that the flat portion 18 is a heating roller as a heating element. 5 is arranged so as to be opposed to the outer peripheral surface 6.

  Further, the exciting coil 7 is disposed in an angle range θ of 90 to 210 degrees along the outer peripheral surface 6 of the heating roller 5 in order to secure magnetic coupling with the heating roller 5 in manufacturing.

  Then, the exciting coil 7 (hereinafter referred to as the flat cross-section coil 7) formed with the flat cross-section wire 13 shown in FIG. 3 and the circular cross-section wire 13 shown in FIG. 4 are formed into the winding bundle. The excitation coil (hereinafter referred to as a circular cross-sectional coil) is configured so that the number of turns of the flat cross-sectional coil 7 is half that of the circular cross-sectional coil when a winding bundle having the same outer shape is formed. Has been.

  Next, the effect | action is demonstrated about the said structure. When the heating roller 5 is heated, when a high frequency current is supplied to the exciting coil 7 by the heating control circuit 4 provided in the fixing device 1, a magnetic field is generated from the exciting coil 7. At that time, magnetic flux is generated from the excitation coil 7 covering the outer peripheral surface 6 of the heating roller 5, and the outer peripheral surface 6 of the heating roller 5 facing the excitation coil 7 is heated. Further, by rotating the heating roller 5 by a motor (not shown), the outer peripheral surface 6 of the heating roller 5 can be uniformly heated by making the outer peripheral surface 6 of the heating roller 5 uniformly face the excitation coil 7. That is, the rotating heating roller 5 generates heat due to an eddy current over the outer peripheral surface 6, and the toner is fixed on the entire paper in contact with the heating roller 5 at a high temperature, so that good image quality can be obtained.

  In this embodiment, the flat section 18 of the wire 13 is opposed to the outer peripheral surface 6 of the heating roller 5 using a litz wire having a flat cross section shown in FIG. Compared with the exciting coil using a litz wire having a circular cross section shown in FIG. 1, the exciting coil 7 is increased by increasing the area of the wire 13 facing the outer peripheral surface 6 of the heating roller 5 approximately twice. By reducing the number of turns of the winding bundle to about half and reducing the inductance of the exciting coil 7, the magnetic coupling between the exciting coil 7 and the heating roller 5 is strengthened. Normally, heating with high power increases the regenerative current and may cause destruction of electronic components such as switching elements. However, by strengthening the magnetic coupling between the excitation coil 7 and the heating roller 5, the excitation coil 7 As a result, the resistance due to the heating roller 5 is increased, the resonance current flowing through the exciting coil 7 is reduced, and the regenerative current is reduced, so that the heating roller 6 can be heated with high power and high efficiency.

  In addition, by making the wire 13 a litz wire whose surface is covered with the first insulating coating 14, the area facing the outer peripheral surface 6 of the heating roller 5 per wire 13 is increased, Since the exciting coil 7 can be formed by tightly winding along the coil support surface 8 without any gap while maintaining the insulation between the adjacent wires 13, the heating roller 5 can be made uniform with high power, high efficiency, and uniformity. While being able to heat with temperature distribution, the binding of the winding bundle of the exciting coil 7 is strengthened, and it is possible to provide the exciting coil 7 in which the wire 13 of the winding bundle is not easily separated.

  As described above, this embodiment corresponds to claim 1 and is an electromagnetic induction heating device for heating the heating roller 5 as a heating element by electromagnetic induction heating by the excitation coil 7 as a coil. Is a litz wire having a flat cross section and is arranged along the outer peripheral surface 6 of the heating roller 5 in an angle range θ of 90 degrees or more and 210 degrees or less.

  In this case, the wire 13 of the exciting coil 7 is a litz wire having a flat cross section, and is arranged along the outer peripheral surface 6 of the heating roller 5 at an angle range θ of 90 degrees or more and 210 degrees or less. By increasing the facing area between the surface 6 and the wire 13 of the exciting coil 7, decreasing the number of turns of the exciting coil 7, and reducing the inductance of the exciting coil 7, the magnetic force between the exciting coil 7 and the heating roller 5 can be reduced. The coupling is strengthened, the electromagnetic induction heating device can be driven at high frequency, and the heating roller 5 can be heated with high power and high efficiency.

  In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible. For example, the dimensional ratio between the X direction and the Y direction in the cross-sectional shape of the wire 13 is not limited to 4: 1 and can be changed as appropriate. Further, the number of the strands 15 accommodated in the wire 13 can be changed as appropriate. Further, the electromagnetic induction heating device of the present invention is not limited to a fixing device of a copying machine as long as it is various devices using an induction heating type heating device.

It is a block diagram which shows the structure of the fixing machine using the electromagnetic induction heating apparatus in the Example of this invention. FIG. 4 is a cross-sectional view of the vicinity of the induction heating unit and the fixing unit. It is sectional drawing of a litz wire of a cross-sectional flat type same as the above. It is sectional drawing of a litz wire of a cross-sectional circle shape same as the above.

Explanation of symbols

5 Heating roller (heating element)
6 Outer surface 7 Excitation coil (coil)
13 Wire θ angle range

Claims (1)

An electromagnetic induction heating device for heating a heating element by electromagnetic induction heating by a coil, wherein the coil is a litz wire having a flat cross-section, and is 90 degrees or more and 210 degrees or less along the outer peripheral surface of the heating element. It is arrange | positioned in the angle range of this, The electromagnetic induction heating apparatus characterized by the above-mentioned.

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