JPH0850422A - Excitation coil, heating device, and image forming apparatus - Google Patents

Abstract

(57) [Summary] [Object] Regarding an exciting coil as a magnetic field generating means, a heating device of an electromagnetic induction heating system using the exciting coil, and an image forming apparatus using the heating device as an image heating device, a wire of the exciting coil Simplify the process of making a ring (coil), reduce cost by improving assemblability, eliminate disconnection due to winding to improve device reliability and durability, (EN) It is possible to configure an optimum heating distribution state and pressure distribution state according to the size of a heated object, increase the range of applicable heated objects, and improve heating performance. [Structure] A sheet-shaped circuit board 3 ₂ in which a coil ring pattern 3a is formed of a conductive material on the surface of an electrically insulating sheet
The ~ 3 ₅ laminating a plurality, exciting coil to form a Senwa third multiple turn through its respective coil loop patterns mutual multilayer circuit substrate by conducting a series in the coil ring pattern end portion 3d entire coil wheel pattern 3a .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exciting coil effectively used as a magnetic field generating means in, for example, an electromagnetic (magnetic) induction heating type heating device.

Further, the present invention relates to a heating device of an electromagnetic induction heating system using the exciting coil and an image forming apparatus using the heating device as an image heating device.

[0003]

2. Description of the Related Art For convenience, an image heating apparatus of an image forming apparatus will be described as an example.

Conventionally, copying machines, laser beam printers,
A toner made of a heat-meltable resin or the like in an image forming apparatus such as a facsimile, a microfilm reader printer, an image display (display) device, and a recording machine by an appropriate image forming process means such as electrophotography, electrostatic recording, magnetic recording, etc. Corresponding to the target image information formed by the direct method or the indirect (transfer) method on the surface of the recording material (electro-fax sheet, electrostatic recording sheet, transfer material sheet, printing paper, etc.) as an image support using A heat roller type device has been generally used as an image heating device for heating and fixing an unfixed toner image as a permanently fixed image on the surface of a recording material carrying the toner image.

This apparatus is composed of a metallic heat roller having a heating element such as a halogen heater inside and a pressure roller having elasticity to press-contact with the fixing roller, and a fixing nip portion which is a pressure-contacting portion of the pair of rollers. By passing a recording material as a material to be heated, the toner image is heated and pressure-fixed.

A film heating type device has also been proposed (Japanese Patent Application Laid-Open No. 63-313182 / Japanese Patent Application Laid-Open No. 2-300182).
No. 157878, Japanese Patent Application Laid-Open No. 4-44075, Japanese Patent Application Laid-Open No. 4-204980, etc.).

This has a heating element (generally referred to as a ceramic heater, hereinafter referred to as a heater) and a heat-resistant film that moves in close contact with the heater, and a material to be heated is brought into close contact with the heater through the film to form a film. This is a heating device that moves the heater position together with the heater to apply the heat energy of the heater to the material to be heated through the film.Because a heater or film with a low heat capacity can be used, the warm-up time is longer than that of the heat roller method. Can be shortened (quick start). Further, since the quick start is possible, it is not necessary to raise the temperature of the heater in advance, so that it is possible to reduce the power consumption and prevent the temperature rise inside the machine.

The applicant has also proposed a device of an electromagnetic induction heating system having advantages such as higher energy efficiency than the film heating system. This is because heat is generated by an eddy current generated in the conductive heat generating member by applying a magnetic field to the conductive heat generating member (conductive member, induction magnetic material, magnetic metal material, magnetic field absorbing conductive material) by the magnetic field generating means (generated eddy current is conductive heat generation). The material to be heated, which is brought into close contact with the conductive heating member, is heated by (converting into Joule heat by the electric resistance of the member).

FIG. 11A shows a model diagram of an example thereof (image heating and fixing device). Reference numeral 101 denotes an exciting coil as a magnetic field generating means, which is a magnetic material core (iron core) 2 and a wire wheel (coil, winding) formed by spirally winding a conductive wire material around the magnetic material core 2.
It is composed of 103. FIG. 11C is a perspective view of the exciting coil 101, in which a conductive wire is spirally wound around each of the magnetic material cores 2 arranged in the laterally elongated member 2a in the shape of a comb along the longitudinal direction to form a coil 103. Is configured.

Reference numeral 4 denotes a stay which supports the exciting coil 101 and also serves as an inner surface guide member of a cylindrical heat generating belt (heat generating film) 6 as a conductive heat generating member described later. The exciting coil 101 has the magnetic flux generating side facing downwards and the stay 4
Supported by.

Reference numeral 5 denotes a belt sliding guide (sliding plate) provided on the lower surface side of the exciting coil 101, which is glass or the like having a relatively small frictional resistance with the inner surface of the heat generating belt 6.

The above members 101 (2, 103), 4, 5
Is hereinafter referred to as a magnetic field generation assembly. A cylindrical heating belt 6 as a conductive heating member is loosely fitted outside the magnetic field generating assemblies 101, 4 and 5. The magnetic field generating assemblies 101, 4 and 5 are laterally long members whose longitudinal direction is the rotation direction of the belt 6 (belt width direction).

Reference numeral 7 is a pressure roller which sandwiches the heat generating belt 6 against the lower surface of the magnetic field generating assemblies 101, 4 and 5 (the lower surface of the belt sliding guide 5) so as to be in pressure contact therewith. N is the pressure contact nip portion (heating nip portion, fixing nip portion). The pressure roller 7 is formed by coating a core metal with an elastic layer such as silicone rubber or fluororubber.

A heating belt 6 as a conductive heating member is shown in FIG.
As shown in the layer structure model diagram of 1 (b), the inner base layer belt 6a and the conductive heating layer 6b formed on the outer surface thereof.
And a surface layer (release layer) 6c formed on the outer surface thereof.

The base layer belt 6a drives the heat generating belt 6
It is a heat-resistant material layer that is flexible but does not expand or contract in order to ensure the stability of conveyance, and has a thickness of 10 μm to 100, for example.
μm Polyimide, Polyamideimide, PEEK, PE
Film materials such as S / PPS / PFA / PTFE / FEP.

The conductive heating layer 6b is made of, for example, Ni, Cu, C.
This is a layer formed of a metal such as r, Fe, or Co by a thickness of 1 μm to 100 μm by a treatment such as plating.

The surface layer 6c is made of PFA / PTFE / FEP /
It is a mixture layer or a single layer of a heat-resistant resin having a good releasability such as a silicone resin.

When the pressure roller 7 is rotationally driven in the counterclockwise direction indicated by the arrow by the driving means M, the belt is driven by the frictional force between the roller 7 and the outer surface of the belt 6 as the pressure roller 7 is rotationally driven. When a rotational force acts on the belt 6, the belt 6 slides in close contact with the belt sliding guide 5, and the magnetic field generating assembly 101.
Rotate the outer circumference of 4.5. A lubricant such as grease or oil may be applied to the lower surface of the belt sliding guide 5 to reduce the frictional resistance with the inner surface of the belt 6.

An alternating current (high frequency) is applied to the coil 103 of the exciting coil 101 from the exciting circuit 8 at a predetermined frequency, whereby the magnetic flux is repeatedly generated and extinguished. The exciting coil 101 is configured such that the magnetic flux (alternating magnetic field) crosses the conductive heat generating layer 6b of the heat generating belt 6 in the pressure contact nip portion N. The magnetic material core 2 is coupled to the main magnetic flux generated in the wire ring 103.

When a fluctuating magnetic field passes through the conductor, an eddy current is generated in the conductive heat generating layer 6b of the heat generating belt 6 so as to generate a magnetic field that prevents the change of the magnetic field. Due to the skin effect of the conductive heat generating layer 6b of the heat generating belt 6, this eddy current almost concentrates on the coil side surface of the conductive heat generating layer 6b,
The conductive heat generating layer 6b generates heat with electric power proportional to the skin resistance of the conductive heat generating layer 6b.

In this state, the recording material P as a heated body is introduced between the rotary heat generating belt 6 and the pressure roller 7 of the pressure contact nip portion N, and the recording material P is brought into close contact with the outer surface of the heat generating belt 6 and the rotary heat generating belt 6. By being nipped and conveyed together with the pressure contact nip portion N, the heat of the conductive heating layer 6b of the heating belt 6 is applied to the recording material P, and the unfixed toner image T on the recording material P is transferred to the recording material P surface. It is heated and fixed. The recording material P that has passed through the pressure contact nip portion N is curvature-separated from the outer surface of the heat generation belt 6 and conveyed.

As described above, since heat is generated directly near the surface layer of the heat generating belt 6, the heat conductivity, heat capacity,
It has the advantages that it can be heated rapidly regardless of its thickness and that it has good thermal efficiency.

In the above description, the exciting coil 101 as the magnetic field generating means has the laterally elongated member 2 as shown in FIG.
A conductive wire is individually wound around each of a plurality of magnetic material cores 2 arranged in a in a comb shape along the longitudinal direction to form a wire ring 103. By connecting the wire rings 103 in series, each of the wire rings 103 is electrically connected in series. Alternatively, one long conductive wire is used and wound around the first magnetic material core 2 on one longitudinal end side of the laterally long base, and the wire ring 10 for the magnetic material core 2 is wound.
3 is formed, and then the conductive wire is wound around the adjacent magnetic material core 2 without being cut, and the wire loop 10 for the magnetic material core 2 is formed.
It is configured such that the work of forming 3 is sequentially performed on each magnetic material core 2 up to the last magnetic material core 2 on the other end side of the longitudinally long base.

[0024]

However, the exciting coil 101 as the magnetic field generating means as described above is: 1) As described above, the process of assembling the coil winding as the coil is complicated, and the cost itself is high. Become.

2) Since the coil winding may always be broken, the reliability was poor.

3) The weight of the coil winding may hinder the weight reduction of a device using the exciting coil.

Further, in the above-mentioned heating device using the exciting coil as the magnetic field generating means, 4) the pressing of the heating part and the pressure roller part is applied by the elastic members provided at both ends. In order to press, the pressure contact between the heating part and the pressure roller part The pressurization state of the longitudinal center of the nip part (nip state)
Becomes unstable and the heating performance is deteriorated.

5) Further, in order to solve the above problem 4), it is necessary to form a highly accurate crown shape on the pressure roller, which hinders improvement in productivity.

Therefore, the present invention solves the above problems 1) to 5) by making it possible to easily and reasonably form and equip a wire ring for this type of exciting coil at a low cost. is there.

[0030]

The present invention is an exciting coil, a heating device, and an image forming apparatus having the following features.

(1) A plurality of sheet-shaped circuit boards, each having a coil ring pattern formed of a conductive material, are laminated on the surface of an electrically insulating sheet-like material, and the respective coil ring patterns of the laminated circuit board are connected to each other at the coil ring pattern ends. An exciting coil, characterized in that a plurality of windings are formed through the entire coil wheel pattern by conducting a series of parts in the section.

(2) The exciting coil according to (1), wherein the coil ring pattern of the sheet-like circuit board is a conductive material pattern printed on the surface of the electrically insulating sheet-like material.

(3) The exciting coil according to (1), characterized in that the magnetic material core is present inside the coil formed by stacking the sheet-shaped circuit boards having the coil wheel pattern.

(4) The exciting coil according to any one of (1) to (3), which has a plurality of wire rings formed by laminating sheet-shaped circuit boards having a coil ring pattern.

(5) The exciting coil according to (4), characterized in that the diameter of the coil formed by stacking the sheet-shaped circuit boards having the coil pattern is different for each coil.

(6) The exciting coil according to (4), wherein the line width of the wire ring formed by stacking the sheet-shaped circuit boards having the coil ring pattern is different for each wire ring.

(7) The heating device according to (4), wherein each heating wire has an independent pressurizing elastic member.

(8) An electromagnetic induction heating system in which a magnetic field is applied to the conductive heat-generating member by the magnetic field generating means to heat the material to be heated in close contact with the conductive heat-generating member by heat generated by the eddy current generated in the conductive heat-generating member. The magnetic field generating means is a heating device, wherein a plurality of sheet-shaped circuit boards each having a coil ring pattern formed of a conductive material on a surface of an electrically insulating sheet-like object are laminated, and the coil ring patterns of the laminated circuit board are mutually laminated. Is an exciting coil in which a plurality of windings are formed through the entire coil wheel pattern by continuously connecting the coil coil pattern end portions to each other.

(9) The heating device according to (8), wherein the coil ring pattern of the sheet-like circuit board is a conductive material pattern printed on the surface of the electrically insulating sheet-like material.

(10) The heating device according to (8), characterized in that the magnetic material core is present inside the wire ring formed by stacking the sheet-shaped circuit boards on which the coil ring pattern is formed.

(11) The heating device according to any one of (8) to (10), which has a plurality of wire rings formed by stacking sheet-shaped circuit boards having a coil ring pattern.

(12) The heating device according to (11), wherein the diameter of the wire ring formed by stacking the sheet-like circuit boards having the coil ring pattern is different for each wire ring.

(13) The heating device according to (11), wherein the line width of the wire ring formed by stacking the sheet-shaped circuit boards having the coil ring pattern is different for each wire ring.

(14) The heating device as set forth in (11), characterized in that each wire ring has an independent pressurizing elastic member.

(15) The heating device as set forth in any one of (8) to (14), characterized in that the conductive heat generating member is a rotating body or an end member that travels and moves.

(16) A nip portion is formed between the heat generating member and the electrically conductive heat generating member, and the nip portion has a pressure member for directly or indirectly press-contacting the material to be heated to the electrically conductive heat generating member. The heating device according to any one of (8) to (15).

(17) The heating device according to (16), characterized in that the pressing member is a rotating body which is rotationally driven or driven to rotate.

(18) The material to be heated is a recording material carrying an image to be heat-treated, and is an image heating device for heat-processing the image on the recording material (8) to (). The heating device according to any one of 17).

(19) An image forming apparatus comprising the heating device according to any one of (8) to (17) as an image heating device.

[0050]

[Action]

a) That is, in the exciting coil of the present invention, the coil (coil) is not formed by winding the conductive wire, but the sheet-shaped circuit board in which the coil ring pattern is formed on the surface of the electrically insulating sheet by the conductive material. A plurality of windings are laminated, and the respective coil wheel patterns of the laminated circuit board are electrically connected in series at the end of the coil wheel pattern to form a plurality of winding wire rings synthetically through the entire coil wheel pattern. Has been simplified and the cost can be reduced.

B) The possibility of disconnection is less likely to occur and reliability is improved as compared with the case where a conductive wire is wound in a coil shape to form a wire ring.

C) The weight of the coil is lighter than that when the coil is formed by winding the conductive wire, and the weight of the device using the exciting coil can be reduced.

D) Further, in the case of an exciting coil having a configuration in which a plurality of coils formed by laminating sheet-like circuit boards having a coil pattern is arranged, the coil diameter (effective diameter of the coil) is set to each coil. The exciting coil is made different for each coil (or for each group of coil groups divided into several groups, the same applies hereinafter), or by varying the coil line width (line width of the coil ring pattern of the circuit board) for each coil. In the heating device having the magnetic field generating means, it is possible to configure an optimum heating distribution state in the longitudinal direction of the heating portion. That is, it becomes possible to configure an optimum heating distribution state according to the size of the object to be heated.

E) Similarly, in the case of an exciting coil having a plurality of wire rings formed by stacking sheet-like circuit boards having a coil ring pattern, by providing an independent pressure elastic member for each wire ring. In the heating device using the exciting coil as the magnetic field generating means, the pressing state along the longitudinal direction of the pressure contact nip portion between the heating portion and the pressure roller portion can be made uniform, and the pressure roller is highly accurate. It is possible to improve the heating performance by stabilizing the pressurization state (nip state) of the longitudinal center portion of the pressure contact nip portion between the heating portion and the pressure roller portion without forming a different crown shape. That is, an optimal heating distribution state can be formed by providing each of the coil portions with an elastic member set to have an optimal pressure.

[0055]

【Example】

<Embodiment 1> (FIGS. 1 to 5) (1) Overall configuration of apparatus FIG. 1 is a schematic cross-sectional view of an electromagnetic induction heating type heating apparatus (image heating and fixing apparatus) using an exciting coil according to the present invention, FIG. 2 is a vertical cross-sectional model view, FIG. 3 is an exploded perspective view of an exciting coil, and FIG. 4 is a diagram showing the connection between coil ring patterns of sheet-like circuit boards to be laminated. The same components and parts as those of the heating device shown in FIG. 11 are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 1 denotes an exciting coil as a magnetic field generating means, which has a magnetic material core (iron core) 2 and a coil ring pattern 3a or necessary wiring patterns 3b and 3c as described later (FIGS. 3 and 4). consisting Senwa 3 was composed of the formed sheet circuit board 3 ₁ to 3 ₆ laminated. The following laminate 3 ₁ to 3 ₆ of the sheet-shaped circuit board referred to as sheet coil.

In this embodiment, four magnetic material cores 2 are arranged along the length of the stay 4 formed of a liquid crystal polymer / phenolic resin or the like on the lower surface of the stay 4 at substantially regular intervals. There, are then provided with a Senwa 3 by the coil ring pattern 3a around the magnetic material core 2 with the stay 4 to the sheet coil 3 ₁ to 3 ₆ attached each magnetic material core 2. Specifically described in the next section (2) with respect to the sheet coil 3 ₁ to 3 _6.

The belt sliding guide 5 is bent and extended from the lower surface of the exciting coil 1 to both longitudinal side portions of the exciting coil 1, and also serves as an inner surface guide member of the heat generating belt 6.

In the case of the apparatus of this embodiment, as in the case of the apparatus shown in FIG. 11, the pressure roller 7 is driven to rotate so that the heat generating belt 6 slides closely on the lower surface of the belt sliding guide 5. Magnetic field generation assembly 1 (2, 3), 4, 5
To rotate around.

Further, the sheet coils 3 ₁ to 3 of the exciting coil 1
By alternating current Senwa 3 of ₆ is applied, the press nip conductive heating layer 6b of the heating belt 6 in (fixing nip portion) N (in FIG. 11 (b)) to electromagnetic induction heating. That is, from the excitation circuit 8 to the coil 3 from 10 kHz to 500 kHz
The magnetic flux is repeatedly generated and extinguished around the wire ring 3 by applying the current at the frequency of. When this fluctuating magnetic field crosses the conductive heat generating layer 6b of the heat generating belt 1, an eddy current is generated in the conductive heat generating layer 6b in the direction of generating a magnetic field that prevents the change of the magnetic field. The eddy current and the electric resistance of the conductive heating layer 6b generate heat in the conductive heating layer.

In this state, the pressure contact nip portion N
The recording material P as a heated body is introduced between the rotating heat generating belt 6 and the pressure roller 7 and closely adheres to the outer surface of the heat generating belt 6, and together with the rotating heat generating belt 6, a pressure contact nip portion (fixing nip portion). By being nipped and conveyed by N, the heat of the conductive heating layer 6b of the heating belt 6 is applied to the recording material P, and the unfixed toner image T on the recording material P is heat-fixed on the surface of the recording material P. It is a thing. The recording material P passing through the pressure nip portion N is separated from the outer surface of the heat generating belt 6 by curvature and conveyed.

[0062] (2) The arrangement now FIGS. 3 and 4 of the sheet coil configuration of the sheet coil 3 ₁ to 3 ₆ will be described.

The sheet coils 3 _{1 to} 3 ₆ are _first to _first in this example.
Sixth Convenience Six sheet-like circuit boards 3 _{1 to} 3 ₆ are sequentially stacked and laminated.

The individual sheet-like circuit boards 3 _{1 to} 3 ₆ are strips of a horizontally long electrically insulating sheet-like material having a width dimension substantially the same as the width of the stay 4 and a length dimension somewhat longer than the length of the stay 4. As a substrate, and four magnetic material core insertion through holes 3d are provided at the center of each substrate in the width direction in correspondence with the arrangement position of the four magnetic material cores 2 provided on the stay 4 along the length of the substrate. the Yes formed, corresponding match between the substrate of the first to sixth respectively the four through holes are vertically superimposed when superimposed convenience six sheet-like circuit board 3 ₁ to 3 _6.

Further, through holes 3e, 3e for stacking and positioning the boards are formed on both sides in the width direction at one end in the longitudinal direction of each of the _first to _sixth sheet-like circuit boards 31 to 36. The stay 4 is provided with positioning pins 4 ₁ , 4 ₁ for engaging the through holes 3 e, 3 e.

First and last first and sixth substrates 3 ₁ 3 ₆
The _second to _fifth four substrates 32 to 35 other than the above are circuit boards in which the coil ring pattern 3a is formed, and the coil ring pattern 3a is formed by a conductive material so as to surround each through hole 3d. is there. The coil ring pattern 3a is a printed pattern made of, for example, a conductive paint. The printed surface may or may not be laminated with an insulating material. End electrodes 3f are provided on one end and the other end of each coil ring pattern 3a, one of which is exposed on the front surface side of the substrate and the other of which is exposed on the back surface side.

The first and sixth boards 3 ₁ and 3 ₆ are circuit boards on which wiring patterns are formed. On the surface of the first substrate 3 ₁ , lead wire patterns 3c and 3c for connecting to the excitation circuit 8 are provided on both longitudinal ends of the first substrate 3 ₁ , and the wire ring 3 formed by stacking the substrates 3 _{2 to} 3 ₅ in series. A wiring pattern 3b for connection is formed. The lead wire patterns 3c and 3c and the wiring pattern 3b are also print patterns made of conductive paint, for example.
The printed surface may or may not be laminated with an insulating material. Further, the end electrodes 3f are also provided at the ends of the lead wire patterns 3c and 3c and the wiring pattern 3b so as to be exposed on the front surface side of the substrate.

[0068] The surface of the substrate 3 ₆ 6 are allowed to form a wiring pattern 3b · 3b for Senwa 3 mutual series connection formed by lamination of the substrate 3 _{2-3 5.} This wiring pattern 3b
Is also a print pattern made of conductive paint, for example. The printed surface may or may not be laminated with an insulating material. Further, the end electrode 3f is also provided at the end of the wiring pattern 3b.
Is exposed on the back side of the substrate.

Thus, the first circuit board 3 ₁ is attached to the stay 4, and the positioning through holes 3e and 3e are attached to the positioning pin 4 _1.
-Fit and engage with 4 ₁ and fit and attach the four magnetic material core insertion through holes 3d to the corresponding four magnetic material cores 2. In the same manner as this, the following 2nd to 6th
The circuit boards 3 _{2 to} 3 ₆ are sequentially attached to the stay 4 to bring the _first to _sixth circuit boards 3 _{1 to} 3 ₆ into a laminated pressure-bonded state.

[0070] The first to in the sixth advance overlapping with stacked crimped state circuit board 3 ₁ to 3 ₆ of the laminate with respect to the stay 4, the positioning pin 4 _1-a positioning hole 3e-3e
It is also possible to make a procedure of fitting and engaging with 4 ₁ and fitting and attaching the four magnetic material core insertion through holes 3 d to the corresponding four magnetic material cores 2.

When the _first to _sixth circuit boards 3 _{1 to} 36 are stacked and pressure-bonded, the upper and lower corresponding end electrodes 3f and 3f are pressure-bonded between the circuit boards to be electrically connected. , The _second to _fifth circuit boards 3 _{2 to} 3 ₅ are laminated so that the coil ring pattern 3 a on the side of each of the circuit boards 3 _{2 to} 3 ₅ is electrically connected around the four magnetic material cores 2 of the stay 4. Therefore, four wire rings 3 are formed. Then, by the wiring pattern 3b and the lead wire pattern 3c of the first and sixth circuit boards 3 ₁ and 3 ₆ , the above four loops 3 are connected in series to the exciting circuit 8 in series.

The end electrodes 3f, which are electrically connected to each other in a corresponding manner between the laminated circuit boards, may be fixedly connected to each other by soldering instead of the above-mentioned pressure-bonding connection.

[0073] circuit substrate provided with the coil loop pattern 3a is not limited to four 3 _{2-3 5} of the present embodiment,
The number may be larger or smaller than this.

The coil ring pattern 3a may be a multiple spiral pattern as shown in FIG. 5, instead of a single pattern as in this embodiment.

Coil wheel pattern 3a, wiring pattern 3
The lead wire pattern 3c may be formed by bending a conductive wire material into a predetermined pattern shape and fixing and mounting the conductive wire material on the circuit board.

<Embodiment 2> (FIG. 6) In this embodiment, in the exciting coil 1 of the above-mentioned Embodiment 1, by stacking the _second to _fifth circuit boards 3 _{2 to} 35, each of the four magnets of the stay 4 is magnetized. Each circuit board 3 ₂ around the material core ₂
To 3 for ₅ side convenience four Senwa 3 formed by a series of conduction of the coil ring pattern 3a sequentially first through the line ring at the right end from the line circle of FIG. 6 above left fourth Senwa 3A · 3B · 3C
When assuming 3D, the coil wire widths (widths of the coil wheel pattern 3a) of the first and fourth coil wheels 3A and 3D and the second and third coil wheels 3B and 3C are different from each other. ,
1st and 4th line wheels 3A and 3D, and 2nd and 3rd line wheels 3B
・ 3C is used to change the amount of current to be applied to change the magnetic force to be excited. In this case, the first and fourth coil wheels 3A and 3D and the second and third coil wheels 3B and 3C are connected in parallel.

By doing so, it is possible to have a heating distribution in the central portion and the end portion in the longitudinal direction of the heating portion (fixing nip portion N) of the heating device, and to optimize the heating depending on the size of the object to be heated. It is now possible to set the state.

The same effect can be achieved by individually setting the diameter of the wire ring, the diameter and the material of the magnetic material core, etc. for each wire ring / magnetic material core.

<Embodiment 3> (FIG. 7) FIG. 7A is a cross-sectional model view of the device of this embodiment, and FIG. 7B is a vertical cross-sectional model view of the left half of the exciting coil.

In this embodiment, each of the magnetic cores 2 is fitted with the sheet coils 3 _{1 to} 3 ₆ independently of each other, and the wire coils 3A, 3B ,.
.. are provided, and elastic members 9A and 9B having different elasticity are provided between the respective seat coils (wire rings) and the stay 4.
Is arranged. Reference numeral 10 is a member that insulates and pressurizes the sheet coil and the elastic member.

With this structure, it is possible to have a distribution of the pressing force at the central portion and the end portion in the longitudinal direction of the pressure contact nip portion N, and without forming a highly accurate crown shape on the pressure roller 7, It is possible to stabilize the pressurization state (nip state) of the longitudinal center portion of the pressure contact nip portion between the heating portion and the pressure roller portion and improve the heating performance. That is, an optimal heating distribution state can be formed by providing each of the coil portions with an elastic member set to have an optimal pressure. That is, it becomes possible to set the optimum pressurization state according to the size of the object to be heated.

Further, even if the elastic members 9A, 9B, ... Are sandwiched and laminated between the sheet coils, the same effect can be obtained. In this case, the elastic members 9A, 9B ... Are preferably made of an insulating material.

<Embodiment 4> (FIG. 8) (a), (b) and (c) of FIG. 8 show another example of the configuration of the electromagnetic induction heating type heating device.

(A) shows magnetic field generating assemblies 1 to 5
Lower surface (lower surface of belt sliding guide 5) and drive roller 3
1 and a driven roller (tension roller) 32, in which a heat generating belt 6 as an endless belt-shaped conductive heat generating member is suspended and stretched between three members, and the drive roller 31 rotationally drives the heat generating belt 6. Is. Reference numeral 33 denotes a pressure roller that is pressed against the lower surface of the belt sliding guide 5 with the heating belt 6 interposed therebetween, and is driven to rotate as the heating belt 6 rotates.

In (b), the magnetic field generating assemblies 1 to
A heating belt 6 as an endless belt-shaped conductive heating member is suspended and stretched between the lower surface of 5 and the driving roller 31 and is rotationally driven by the driving roller 31.

In (c), the heat generating belt 6 serving as a conductive heat generating member is not an endless belt-shaped one but a long end film wound in a roll is used, and a magnetic field is generated from the feeding shaft 34 side. The assembly 1 to 5 is configured to travel at a predetermined speed to the winding shaft 35 side via the lower surface.

<Embodiment 5> (FIG. 9) In this embodiment, the belt sliding guide 5 of the magnetic field generating assemblies 1 to 5 of the above-described heating device is the conductive heat generating member 5A, and the belt 6 is used.
Is a heat resistant film 6A having no conductive heat generating layer.

In the case of the present embodiment, the magnetic flux generated by the exciting coil 1 causes the belt sliding guide 5 as a conductive heat generating member to generate heat by magnetic induction, and the heat is generated in the pressure contact nip portion N via the heat resistant film 6A. The toner image is heated and fixed by being applied to a recording material as a heated body that is pressed and closely attached to the outer surface of the permeable film 6A.

In each of the above embodiments, the direction of the magnetic field is configured to enter the conductive heat generating layer 6b of the heat generating belt 6 as the conductive heat generating member or the belt sliding guide 5 as the conductive heat generating member vertically. , A magnetic field may be applied parallel to the plane.

When a material having a Curie temperature required for fixing is used as the material for forming the conductive heat generating layer 6b or the belt sliding guide 5, the specific heat increases when the Curie temperature approaches the Curie temperature and changes to internal energy. Therefore, self-temperature control becomes possible. When the temperature exceeds the Curie temperature, the spontaneous magnetization disappears, whereby the magnetic field generated in the conductive heat generating layer 6b or the belt sliding guide 5 is reduced below the Curie temperature, so that the eddy current decreases and the heat generation is suppressed. Self temperature control becomes possible. The Curie point is 100 ° C to 2 depending on the softening point of the toner.
00 ° C is preferred.

Alternatively, since the combined inductance between the exciting coil 1 and the heating belt 6 or the belt sliding guide 5 changes greatly near the Curie temperature, the temperature is detected on the side of the exciting circuit 8 that applies a high frequency to the exciting coil 1. It is also possible to control the temperature.

As the material of the magnetic material core 2 of the exciting coil 1, it is preferable to use one having a low Curie point.
When the conveyance operation of the apparatus is stopped and the so-called runaway state in which the heating control is impossible is performed, the temperature of the magnetic material core 2 starts to rise. As a result, when viewed from the circuit that generates a high frequency, the exciting coil 1
Since it seems that the inductance of the excitation circuit 8 becomes large, when the excitation circuit 8 tries to match the frequency, it gradually changes to the high frequency side, energy is consumed as power loss of the excitation circuit 8, and the energy supplied to the excitation coil 1 decreases. , Runaway is prevented. Specifically, the Curie point is 100 ° C
It is recommended to select at ~ 250 ° C. If the temperature is 100 ° C. or less, the temperature is lower than the melting point of the toner and the temperature rises even if the belt 6 or the sliding plate 5A is thermally insulated.
It does not prevent runaway at temperatures above 50 ° C.

The heat generating belt 6 and the heat resistant film 6A may be roller bodies.

The apparatus is not limited to the fixing apparatus of the embodiment. For example, an apparatus for heating a recording material carrying an image to modify the surface properties such as gloss, a hypothetical wearing apparatus, and the like can be widely used for heat treatment of a heated object. It can be used as a means / device for It can also be used in a device for heating and drying while conveying a sheet-like material.

<Embodiment 6> (FIG. 10) In this embodiment, for example, an outline of an example of an image forming apparatus in which the heating apparatus of the magnetic induction heating system of the above-described Embodiment 1 is used as an image heating fixing apparatus (image heating apparatus) 55 It is a block diagram. The image forming apparatus of this example is a laser beam printer using an electrophotographic process.

Reference numeral 41 is a rotary drum type electrophotographic photosensitive member (hereinafter referred to as photosensitive drum) as an image supporting member (first image supporting member). The photosensitive drum 41 is rotationally driven in the clockwise direction indicated by the arrow at a predetermined peripheral speed (process speed), and in the course of the rotation, the primary charger 42 uniformly charges the negative dark potential V _D.

Reference numeral 43 denotes a laser beam scanner which emits a laser beam L modulated in accordance with a time series electric digital pixel signal of target image information input from a host device such as an image reading device, a word processor and a computer (not shown). Then, the surface of the photosensitive drum 41, which has been negatively and uniformly charged by the primary charger 42 as described above, is scanned and exposed by the laser beam, so that the potential absolute value of the exposed portion becomes small and becomes the bright potential V _L , and the exposed portion rotates. An electrostatic latent image corresponding to the target image information is formed on the surface of the exposure drum 41.

Next, the latent image is subjected to reversal development (laser exposure portion V
Toner is attached to _L ) to make it visible.

The developing device 44 has a developing sleeve 44a which is driven to rotate, and the outer peripheral surface of the sleeve is coated with a thin layer of toner having a negative charge to face the surface of the photosensitive drum 41. Absolute value is photosensitive drum 4
By applying the developing bias voltage _VDC which is smaller than the dark potential VD of 1 and larger than the bright potential _VL , the toner on the sleeve 44a is transferred only to the portion of the light potential _VL of the photosensitive drum 41 and the latent image is transferred. The image is visualized (reversal development).

On the other hand, the recording material (second image carrier, transfer paper) P stacked and set on the paper feed tray 45 is fed out and fed one by one by the paper feed roller 46, and the conveyance guide 4
7, a nip portion (transfer portion) 52 between the photosensitive drum 41 and the transfer roller 50 as a transfer member which is brought into contact with the photosensitive drum 41 and a transfer bias is applied by the power source 51 via the pair of registration rollers 48 and the pre-transfer guide 49. The toner image on the surface of the photosensitive drum 41 is sequentially transferred to the surface of the fed recording material P by being fed at an appropriate timing synchronized with the rotation of the photosensitive drum 41. Transfer roller 50 as transfer member
The resistance value of 10 ⁸ to 10 ⁹ Ωm is suitable.

The recording material P that has passed through the transfer portion 52 is separated from the surface of the photosensitive drum 41, and is fixed by the conveyance guide 54 to the fixing device 55.
Then, the transferred toner image is fixed and is output to the paper discharge tray 56 as an image formed product (print). The surface of the photosensitive drum 41 after separation of the recording material is a cleaning device 53.
Then, the residual toner on the surface of the photosensitive drum such as residual toner after transfer is removed, and the surface is cleaned to be repeatedly used for image formation.

[0102]

As described above, according to the present invention, since the exciting coil is not the conventional method of forming the coil by winding the conductive wire, the process of making the coil is simplified, The cost can be reduced by improving the reliability, and disconnection due to winding does not occur, so that the reliability and durability of the device are improved. In the heating device, the optimum heating distribution state according to the size of the object to be heated,
It becomes possible to configure a pressure distribution state, the range of applicable objects to be heated is increased, and the heating performance can be improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a heating device (image heating and fixing device) according to a first embodiment.

[Figure 2] Vertical section model

FIG. 3 is an exploded perspective view of an exciting coil

FIG. 4 is a diagram showing how to connect the coil ring patterns to each other between the laminated sheet-like circuit boards.

FIG. 5 is a plan view of another pattern example of the coil wheel pattern.

FIG. 6 is an exploded perspective view of an exciting coil of the heating device according to the second embodiment.

FIG. 7 (a) is a schematic cross-sectional view of the device of Example 3;
(B) is a vertical cross-section model diagram of the left half of the exciting coil

8 (a), (b), and (c) are schematic views of another example of the configuration of the electromagnetic induction heating type heating device (Example 4).

FIG. 9 is a schematic view of the configuration of a heating device of still another electromagnetic induction heating system (Example 5).

FIG. 10 is a schematic configuration diagram of an example of an image forming apparatus (Example 6).

11A is a schematic view of the configuration of a conventional electromagnetic induction heating type heating device, FIG. 11B is a model diagram of a layer structure of a heating belt, and FIG. 11C is a perspective view of an exciting coil.

[Explanation of symbols]

1.101 Excitation coil (magnetic field generating means) 2 Magnetic material core (iron core) 3.103 Wire ring (coil) 3 _{1 to} 3 ₆ Sheet circuit board 3a Coil ring pattern 3b Wiring pattern 3c Lead wire pattern 3d Magnetic material core Insertion through hole 3e Positioning through hole 4 Stay 4 ₁ Positioning pin 5 Belt sliding guide 6 Heat generation belt 6a Base layer belt 6b Conductive heat generation layer 6c Surface layer (release layer) 7 Pressure roller 8 Excitation circuit M Pressure roller drive means N Pressure contact nip Part (heating nip part, fixing nip part) P heated object (recording material) T toner image

Claims (19)

[Claims] 1. A plurality of sheet-shaped circuit boards, each having a coil ring pattern formed of a conductive material on the surface of an electrically insulating sheet-like material, are laminated, and the coil ring patterns of the laminated circuit board are connected to each other at the coil ring pattern end portions. 2. An exciting coil characterized in that a plurality of windings are formed through the entire coil wheel pattern by continuously conducting the coil. 2. The exciting coil according to claim 1, wherein the coil ring pattern of the sheet-shaped circuit board is a conductive material pattern printed on the surface of an electrically insulating sheet-shaped material. 3. The exciting coil according to claim 1, wherein a magnetic material core is present inside a wire ring formed by stacking sheet-shaped circuit boards having a coil ring pattern. 4. The exciting coil according to claim 1, further comprising a plurality of wire rings formed by stacking sheet-shaped circuit boards having a coil ring pattern. 5. The exciting coil according to claim 4, wherein the diameter of the coil formed by stacking the sheet-shaped circuit boards having the coil pattern is different for each coil. 6. The exciting coil according to claim 4, wherein the line width of the wire ring formed by stacking the sheet-shaped circuit boards having the coil ring pattern is different for each wire ring. 7. The heating device according to claim 4, wherein each wire ring has an independent pressurizing elastic member. 8. An electromagnetic induction heating method for heating a material to be heated which is brought into close contact with the conductive heat generating member by applying a magnetic field to the conductive heat generating member by magnetic field generating means to generate heat by an eddy current generated in the conductive heat generating member. The magnetic field generating means is a device, wherein a plurality of sheet-shaped circuit boards each having a coil ring pattern formed of a conductive material on a surface of an electrically insulating sheet-like object are laminated, and the coil ring patterns of the laminated circuit board are mutually laminated. A heating device, which is an exciting coil in which a plurality of windings are formed through the entire coil wheel pattern by continuously connecting the coil wheel pattern ends. 9. The heating device according to claim 8, wherein the coil ring pattern of the sheet-like circuit board is a conductive material pattern printed on the surface of the electrically insulating sheet-like material. 10. The heating device according to claim 8, wherein a magnetic material core is present inside a wire ring formed by stacking sheet-shaped circuit boards having a coil ring pattern. 11. The heating device according to claim 8, further comprising a plurality of wire rings formed by laminating sheet-shaped circuit boards having a coil ring pattern. 12. The heating device according to claim 11, wherein the diameter of a wire ring formed by stacking sheet-shaped circuit boards having a coil ring pattern is different for each wire ring. 13. The heating device according to claim 11, wherein the line width of the wire ring formed by stacking the sheet-shaped circuit boards having the coil ring pattern is different for each wire ring. 14. The heating device according to claim 11, wherein each heating wire has an independent pressurizing elastic member. 15. The heating device according to claim 8, wherein the conductive heat generating member is a rotating body or an end member that travels and moves. 16. A nip portion is formed between the conductive heat generating member and a pressurizing member for pressurizing and adhering the material to be heated directly or indirectly to the conductive heat generating member at the nip portion. Item 16. The heating device according to any one of items 8 to 15. 17. The heating device according to claim 16, wherein the pressing member is a rotating body that is rotationally driven or driven to rotate. 18. The heating target material is a recording material carrying an image to be heat-treated, and the image heating device heat-treats the image on the recording material.
7. The heating device according to any one of 7. 19. An image forming apparatus comprising the heating device according to any one of claims 8 to 17 as an image heating device.