JP2000131976A - Heating device, image heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the smooth carrying of a belt and also prevent the bias of the belt in a belt system heating device. SOLUTION: This device has an endless belt 10, supporting members 16a and 16b supporting the belt 10, and a pressing member 30 brought into mutually press-contact with the belt 10 and forming a nip part N. This heating device has a heating element inside the belt 10, heats a member P to be heated, and has an elastic surface wave generating element 40 on a surface opposed to the member 30 inside the belt 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heating device, an image heating device, and an image forming device.

More specifically, a belt type (belt heating type) heating device, that is, a heating device having a rotating endless belt and heating a member to be heated by heat from the belt side, an image heating device, and a heating device The present invention relates to an image forming apparatus such as an electrophotographic apparatus and an electrostatic recording apparatus provided as an image heating apparatus.

[0003]

2. Description of the Related Art For convenience, an image heating device (fixing device, fixing device) for heating and fixing a toner image to a recording material provided in an image forming apparatus such as a copying machine or a printer will be described as an example.

In an image forming apparatus, a recording material (transfer material sheet, electrofax sheet, electrostatic recording paper, OHP sheet, or the like) is applied to an appropriate image forming process means such as an electrophotographic process, an electrostatic recording process, and a magnetic recording process. A fixing device that heats and fixes an unfixed image (toner image) of the target image information formed and supported on a printing paper or a format paper by a transfer method or a direct method as a permanent fixed image on a surface of a recording material is used. Heat roller type devices have been widely used. Recently, belt heating type devices have been put into practical use. Also, an electromagnetic induction heating system has been proposed.

In a belt heating type apparatus, a lubricant (grease) is interposed between a belt and a belt supporting member as proposed in Japanese Patent Application Laid-Open No. Hei 5-27619. And the slidability between them.

[0006]

As described above, in the heating device of the belt heating type, since the portion where the inner surface of the belt and the belt supporting member slide on the nip portion slides, heat-resistant grease is applied to the sliding surface. However, when the temperature of the heat-resistant grease is low, such as when the device is started, sufficient lubricity cannot be obtained due to the high viscosity of the heat-resistant grease, and the belt slides against the belt support member. In some cases, the non-heated material or the pressurized rotating body slips (slip of the material to be heated with respect to the belt) with respect to the belt that has become unable to move smoothly due to increased dynamic resistance. In addition, heat-resistant grease deteriorates in durability and loses lubricity, which is one of the factors that limit the durability life of the device.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems by directly conveying the belt by a belt support member on the inner surface of the belt, and to prevent the belt from shifting.

[0008]

SUMMARY OF THE INVENTION The present invention is a heating device, an image heating device, and an image forming device having the following constitutions.

(1) A magnetic field generating means, an electromagnetic induction heating member for generating electromagnetic induction by the action of the magnetic field of the magnetic field generating means, and a nip portion of a member to be heated by mutual pressure contact with the electromagnetic induction heating member. A heating member for heating a member to be heated by heat generated by an electromagnetic induction heating member generated by a magnetic field generated by the magnetic field generation means, wherein the electromagnetic induction heating member is an endless belt, and the inside of the endless belt is A surface acoustic wave generating element on a surface facing the pressure member.

(2) An endless belt, a support member for supporting the endless belt, a pressing member for forming a nip portion by mutually pressing the endless belt, and a heating element in the endless belt; A heating device for heating a member to be heated, comprising a surface acoustic wave generating element on a surface of the endless belt facing a pressing member.

(3) In the heating device according to (1) or (2), the surface acoustic wave generating element includes at least a piezoelectric member, an electrode provided on the piezoelectric member, and an elastic layer.
A heating device, wherein a high-frequency voltage of 20 kHz or more is applied to the electrode.

(4) The heating device according to (3), wherein the surface acoustic wave generating element has a sliding layer on a contact surface with an endless belt.

(5) In the heating device according to (3) or (4), the electrode is divided into a plurality of parts in a longitudinal direction of the surface acoustic wave generating element, and a high frequency voltage is applied to each electrode. A heating device.

(6) The heating device according to (5), wherein the electrode is divided into two in the longitudinal direction of the surface acoustic wave generating element, and a high frequency voltage is applied to each electrode. apparatus.

(7) The heating device according to any one of (3) to (6), further comprising a detecting means for detecting a longitudinal movement of the endless belt, and a movement of the endless belt obtained from the detecting means. A heating device, wherein the amplitude of the high-frequency voltage is changed according to the amount.

(8) The heating apparatus according to (5), wherein the electrode is divided into three in the longitudinal direction of the surface acoustic wave generating element, and a high-frequency voltage is applied to each electrode. apparatus.

(9) The heating device according to (8), wherein the amplitude of the voltage applied to the central divided electrode is larger than the amplitude of the voltage applied to the divided electrodes at both ends.

(10) An image heating apparatus for heating an image on a recording material, wherein the image heating means is as described in (1) to (9) above.
An image heating apparatus according to any one of claims 1 to 4.

(11) An image forming means for forming an image on the recording material, and an image heating means for heating the image formed on the recording material, wherein the image heating means is as described in (1) to (9) above. An image forming apparatus, which is the heating apparatus according to any one of the above.

<Operation> An endless belt can be directly conveyed by a surface acoustic wave in a nip portion between an endless belt and a member holding the endless belt. Since the sheet is conveyed on the nip surface, a conventionally required drive motor and drive gear are not required. In addition, since the conventional sliding portion is a driving portion, slippage of the material to be heated and the like with respect to the belt does not occur. In addition, since the endless belt can be prevented from shifting in the longitudinal direction, stable belt running can be obtained. Since the endless belt is directly driven, the belt conveyance speed can be kept constant without being affected by a change in the belt conveyance speed due to thermal expansion of the pressing member.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment (FIGS. 1 to 13) (1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus. The image forming apparatus of this example is an electrophotographic color printer.

Reference numeral 101 denotes a photosensitive drum (image bearing member) made of an organic photosensitive member or an amorphous silicon photosensitive member, and is rotated at a predetermined process speed (peripheral speed) in a counterclockwise direction indicated by an arrow.

The photosensitive drum 101 undergoes a uniform charging process of a predetermined polarity and potential by a charging device 102 such as a charging roller during the rotation process.

Next, a laser beam 103 output from a laser optical box (laser scanner) 110 is placed on the charged surface.
And scanning exposure processing of the target image information.

The laser optical box 110 is modulated (on / off) in response to a time-series electric digital pixel signal of target image information from an image signal generator such as an image reader (not shown).
And outputs the laser beam 103 to the photosensitive drum 101
By scanning and exposing the surface, an electrostatic latent image corresponding to the target image information is formed on the surface of the drum 101.

A mirror 109 deflects the output laser light 103 from the laser optical box 110 to the exposure position of the photosensitive drum 101.

In the case of forming a full-color image, scanning exposure and latent image formation are performed on a first color-separated component image of a target full-color image, for example, a yellow component image. Is developed as a yellow toner image by the operation of the yellow developing device 104Y.

The yellow toner image is the photosensitive drum 1
01 and the intermediate transfer drum 105 at a primary transfer portion T1 which is a contact portion (or a close portion) of the intermediate transfer drum 105.
05 is transferred to the surface.

The intermediate transfer drum 105 has a medium-resistance elastic layer and a high-resistance surface layer on a metal drum, and has substantially the same peripheral speed as the photosensitive drum 101 in contact with or close to the photosensitive drum 101. Is rotated clockwise as indicated by the arrow, a bias potential is applied, and the toner image on the photosensitive drum 101 is transferred to the surface of the intermediate transfer drum 105 by a potential difference from the photosensitive drum 101.

After the transfer of the toner image onto the surface of the intermediate transfer drum 105, the surface of the rotating photosensitive drum 101 is
7 removes adhered residues such as transfer residual toner and is cleaned.

The process cycle of charging, scanning exposure, development, primary transfer, and cleaning as described above is performed by the second color separation component image (for example, magenta component image,
The magenta developing device 104M is activated), the third color-separated component image (for example, the cyan component image, the cyan developing device 104C is activated), and the fourth color-separated component image (for example, the black component image, the black developing device 104BK is activated). Each color separation component image is sequentially executed, and four toner images of a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image are sequentially superimposed and transferred onto the surface of the intermediate transfer drum 105, and a desired full-color image is transferred. Are synthesized and formed.

The color toner image synthesized and formed on the surface of the rotary intermediate transfer drum 105 is transferred to the secondary transfer portion T2, which is a contact nip portion between the rotary intermediate transfer drum 105 and the transfer roller 106, in the secondary transfer portion T2. The recording material P sent from the paper supply unit (not shown) to the transfer unit T2 at a predetermined timing.
Is transferred to the surface. The transfer roller 106 is a recording material P
The composite color toner images are sequentially and collectively transferred from the surface of the intermediate transfer drum 105 to the recording material P by supplying an electric charge having a polarity opposite to that of the toner from the back surface.

The recording material P that has passed through the secondary transfer portion T2 is
After being separated from the surface of the intermediate transfer drum 105 and introduced into the image heating device (fixing device) 100, the unfixed toner image is heated and fixed and discharged as a color image formed product to a paper output tray (not shown) outside the machine. Is done. In the present embodiment, the toner containing a low softening substance is used.

The image heating apparatus 100 will be described in detail in the following section (2).

After the transfer of the color toner image onto the recording material P, the rotating intermediate transfer drum 105 is cleaned by the cleaner 108 after removing the residual toner such as untransferred toner and paper dust. The cleaner 108 is normally kept in a non-contact state with the intermediate transfer drum 105. In the process of executing the secondary transfer of the color toner image from the intermediate transfer drum 105 to the recording material P, the intermediate image after the toner image is transferred. The transfer drum 105 is held in contact with the surface.

The transfer roller 106 is also always kept in a non-contact state with the intermediate transfer drum 105, and during the secondary transfer of the color toner image from the intermediate transfer drum 105 to the recording material P, the intermediate transfer drum 105
Is kept in contact with the recording material P via the recording material P.

The apparatus of the present embodiment can also execute a print mode of a mono-color image such as a black-and-white image. Also, a double-sided image print mode or a multiple image print mode can be executed.

In the case of the double-sided image print mode, the recording material P on which the first-side image has been printed out of the image heating device 100
Is turned upside down via a recirculation transport mechanism (not shown), is sent again to the secondary transfer portion T2, receives the toner image transfer on the second surface, and is again introduced into the image heating device 100 and
The two-sided image print is output by receiving the fixing process of the toner image on the surface.

In the case of the multiple image print mode, the recording material P on which the first image has been printed out of the image heating device 100 is printed.
Is sent to the secondary transfer portion T2 again without being turned upside down via a recirculation transport mechanism (not shown) and receives the second transfer of the toner image on the surface on which the first image has been printed. The multi-image print is output by being subjected to the second toner image fixing process after being introduced.

(2) Image Heating Apparatus 100 FIG. 2 is a schematic cross-sectional view of a main part of the image heating apparatus 100 of this embodiment.
FIG. 3 is a front model view of a main part, and FIG. 4 is a longitudinal sectional model view of a main part.

The image heating apparatus 100 of the present embodiment is an apparatus of an electromagnetic induction heating system using a cylindrical electromagnetic induction heating belt (hereinafter, referred to as a fixing belt).

The magnetic field generating means includes magnetic cores 17a, 17b,
17c and the exciting coil 18.

The magnetic cores 17a, 17b and 17c are members having a high magnetic permeability, and are preferably made of a material used for a transformer core such as ferrite or permalloy, and more preferably ferrite which has a small loss even at 100 kHz or more.

The exciting coil 18 uses a bundle (bundle) of a plurality of copper thin wires, each of which is insulated and coated, as a conducting wire (electric wire) constituting a coil (wire loop).
This is wound a plurality of times to form an exciting coil. In this example, the exciting coil 18 is formed by winding 10 turns.

As the insulating coating, a coating having heat resistance is preferably used in consideration of heat conduction due to heat generation of the fixing belt 10.
In this example, a coating with polyimide is used, and the heat resistance temperature is 220 ° C. Further, the density may be improved by applying a pressure from the outside of the exciting coil 18.

Reference numerals 16a and 16b denote left and right belt guide members having a substantially semicircular cross section as an insulating support member, and a belt guide assembly of a substantially cylindrical body is formed by abutment of both 16a and 16b.

The belt guide assemblies 16a and 16
Outside the b, a cylindrical fixing belt 10 of electromagnetic induction heat generation as an induction heat generation member is loosely fitted. FIG.
_LF is the length of the fixing belt 10.

The magnetic cores 17a, 17b and 17c, which are the magnetic field generating means, and the exciting coil 18 are held inside the belt guide member 16a on one side of the belt guide assemblies 16a and 16b.

As the material of the belt guide members 16a and 16b, those having excellent insulation properties and good heat resistance in order to secure insulation from the fixing film 10 are preferable. For example, phenol resin, fluorine resin, polyimide resin, polyamide resin, polyamide imide resin, PEEK resin, PES resin, PS resin, PFA resin, PTFE resin, FEP resin,
It is preferable to select LCP resin or the like.

Reference numeral 22 denotes a horizontally long pressing rigid stay which is disposed in contact with the inner flat surface portion corresponding to the nip portion N of the belt guide member 16a.

Reference numeral 19 denotes a belt guide assembly 16a / 1
Magnetic core 17a.1 as magnetic field generating means inside 6b
It is an insulating member for insulating between the excitation coils 18 and the excitation coil 18 and the rigid stay 22 for pressurization, and is made of the same material as the belt guide members 16a and 16b.

Reference numeral 40 denotes a horizontally long surface acoustic wave generating element disposed along the longitudinal direction on the lower surface flat portion corresponding to the nip portion N of the belt guide member 16a.

In FIGS. 3 and 4, reference numerals 23a and 23b denote flange members which are externally fitted to the left and right ends of the belt guide assemblies 16a and 16b and fixed in position.
The end portion of the fixing belt 10 fitted to the belt guide assemblies 16a and 16b is regulated and held.

As shown in FIG. 5, an excitation circuit 27 is connected to the power supply sections 18a and 18b of the excitation coil 18. The excitation circuit 27 can generate a high frequency of 20 kHz to 500 kHz by a switching power supply. The exciting coil 18 generates an alternating magnetic flux by an alternating current (high-frequency current) supplied from the exciting circuit 27.

Reference numeral 30 denotes a pressure roller, and a core metal 30a,
Heat resistance of silicone rubber, fluoro rubber, fluoro resin, etc.
An elastic material layer 30b is provided, and both ends of the core metal 30a are rotatably supported between chassis side plates (not shown) of the apparatus. In FIG. 3, L _R is the length of the pressure roller 30.

Pressing springs 25a and 25b are contracted between both ends of the pressing rigid stay 22 and the spring receiving members 29a and 29b on the apparatus chassis side, thereby applying a pressing force to the pressing rigid stay 22. ing.

Thus, the lower surface of the surface acoustic wave generating element 40 disposed on the lower surface of the belt guide member 16a and the upper surface of the pressure roller 30 are pressed against each other with the fixing belt 10 interposed therebetween to form a fixing nip portion N having a predetermined width. Is done.

As described later, the surface acoustic wave generating element 40
The fixing belt 10 is directly conveyed in the fixing nip portion N by the surface acoustic wave generated in the element 40 by the application of the high-frequency voltage to the electrodes, and the fixing belt 10 is moved in the clockwise direction indicated by the arrow at a predetermined peripheral speed. 16
The outer circumference of a 16b is rotated. Fixing nip N
A pressure roller 30 pressed against the outer surface of the fixing belt 10
Rotates at a speed substantially corresponding to the rotation speed of the fixing belt 10. The belt guide assemblies 16a and 16b support the fixing belt 10 and play a role in ensuring the conveyance stability when the belt 10 rotates.

16e (FIG. 5) is a belt guide member 16a.
Are formed on the side surface of the belt guide member at intervals along the longitudinal direction of the belt guide member. This convex rib portion 16e is
The contact sliding resistance between the side surface of the fixing belt 10 and the inner surface of the fixing belt 10 is reduced to reduce the rotational load of the fixing belt 10. Such a convex rib portion 16e can be similarly formed on the side surface of the other belt guide member 16b.

FIG. 6 shows an exciting coil 18 as a magnetic field generating means.
FIG. 3 schematically shows how alternating magnetic fluxes are generated from the magnetic cores 17a, 17b, and 17c. The magnetic flux C represents a part of the generated alternating magnetic flux.

The alternating magnetic flux C guided to the magnetic cores 17a, 17b, and 17c is applied between the magnetic cores 17a and 17b and between the magnetic cores 17a and 17c by the electromagnetic induction heating layer 1 of the fixing belt 10 (FIG. 6). 8) An eddy current is generated.
This eddy current generates Joule heat (eddy current loss) in the electromagnetic induction heating layer 1 due to the specific resistance of the electromagnetic induction heating layer 1.

The heat value Q here is determined by the density of the magnetic flux passing through the electromagnetic induction heating layer 1 and has a distribution as shown in the graph of FIG. 6, the center of the magnetic core 17a is 0 on the vertical axis, and the fixing belt 10
Represents the position of. The horizontal axis represents the amount of heat generated in the electromagnetic induction heating layer 1 of the fixing belt 10. Here, the heating area H is defined as an area where the heating value is Q / e or more, where Q is the maximum heating value. This is an area where the amount of heat required for fixing can be obtained.

The temperature of the fixing nip portion N is
By controlling the current supply to the excitation coil 18 by a temperature control system (not shown) including (FIG. 2), the temperature is controlled so that a predetermined temperature is maintained.

In the apparatus of this embodiment, a temperature sensor 26 such as a thermistor for detecting the temperature of the fixing belt 10 is connected to the outer surface of the belt guide member 16b at a position corresponding to the inner side of the fixing belt 10 and immediately after the fixing nip portion N. And the temperature of the fixing nip portion N is controlled.

Thus, the fixing belt 10 is driven to rotate around the belt guide assemblies 16a and 16b by the surface acoustic waves generated by the application of the high-frequency voltage to the surface acoustic wave generating element 40, and the fixing belt 10 is rotated by the excitation circuit 27 (FIG. 5). An unfixed toner image conveyed from an image forming unit (not shown) in a state in which the fixing nip N rises to a predetermined temperature and the temperature is adjusted by the electromagnetic induction heating of the fixing belt 10 due to the power supply to the excitation coil 18. The recording material P on which the toner image t is formed is fixed to the fixing belt 10 of the fixing nip portion N and the pressure roller 30.
The fixing roller is introduced with the image surface facing upward, that is, opposed to the fixing belt surface. At the fixing nip portion N, the image surface is in close contact with the outer surface of the fixing belt 10 and the fixing nip portion N is pinched together with the fixing belt 10. Conveyed.

In the process in which the recording material P is nipped and conveyed through the fixing nip portion N together with the fixing belt 10, the unfixed toner image t on the recording material P is heated by electromagnetic induction heating of the fixing belt 10. Is heat-fixed.

At this time, the recording material P and the unfixed toner t are preheated on the entrance guide. When the recording material P passes through the fixing nip portion N, it is separated from the outer surface of the rotary fixing belt 10 and is discharged and conveyed. After passing through the fixing nip, the heat-fixed toner image on the recording material is cooled and becomes a permanent fixed image.

The flange members 23a and 23b receive the ends of the fixing belt 10 when the fixing belt 10 rotates, and play a role in regulating the shift of the fixing belt 10 along the length of the belt guide assemblies 16a and 16b. The flange members 23a and 23b may be configured to rotate following the fixing belt 10.

In this embodiment, since the toner containing a low softening substance is used in the toner t, the fixing device is not provided with an oil application mechanism for preventing offset, but the toner not containing the low softening substance is used. In this case, an oil application mechanism may be provided. Also, when a toner containing a low softening substance is used, oil application or cooling separation may be performed.

A) Fixing Belt 10 FIG. 7 is a schematic diagram of the layer structure of the fixing belt 10 in this embodiment. The fixing belt 10 of the present embodiment includes an electromagnetic induction heating layer 1 made of a metal belt or the like, which serves as a base layer of the electromagnetic induction heating fixing belt, an elastic layer 2 laminated on the outer surface thereof, and a separation layer laminated on the outer surface thereof. It has a composite structure of the mold layer 3. A primer layer (not shown) may be provided between each layer for adhesion between the electromagnetic induction heat generating layer 1 and the elastic layer 2 and adhesion between the elastic layer 2 and the release layer 3.

In the cylindrical fixing belt 10, the electromagnetic induction heating layer 1 is on the inner side, and the release layer 3 is on the outer side. As described above, when the alternating magnetic flux acts on the electromagnetic induction heating layer 1, an eddy current is generated in the electromagnetic induction heating layer 1, and the electromagnetic induction heating layer 1 generates heat. The heat heats the recording material P as the heating material passed through the fixing nip N via the elastic layer 2 and the release layer 3 to heat and fix the toner image t.

A. Electromagnetic induction heat generating layer 1 The electromagnetic induction heat generating layer 1 may be made of a nonmagnetic metal, but is preferably made of a ferromagnetic metal such as nickel, iron, ferromagnetic SUS, and nickel-cobalt alloy.

It is preferable that the thickness is larger than the skin depth represented by the following formula and 200 μm or less. The skin depth σ [m] is determined by the frequency f [Hz] of the excitation circuit and the magnetic permeability μ.
And σ = 503 × (ρ / fμ) ^1/2 .

This indicates the depth of absorption of electromagnetic waves used in electromagnetic induction. At a depth deeper than this, the intensity of the electromagnetic waves is 1 / e or less. (FIG. 8).

Therefore, the thickness of the electromagnetic induction heating layer 1 is preferably 1 to 100 μm. If the thickness of the electromagnetic induction heat-generating layer 1 is smaller than 1 μm, most of the electromagnetic energy cannot be absorbed, and the efficiency becomes poor. On the other hand, if the thickness of the electromagnetic induction heating layer 1 exceeds 100 μm, the rigidity becomes too high, and the flexibility deteriorates, which is not practical for use as a rotating body. Therefore, the thickness of the electromagnetic induction heating layer 1 is 1 to 10
0 μm is preferred.

B. Elastic Layer 2 The elastic layer 2 is made of silicone rubber, fluorine rubber, fluorosilicone rubber, or the like, and has good heat resistance and good thermal conductivity.

The thickness of the elastic layer 2 is preferably from 10 to 1000 μm. The elastic layer 2 has a thickness necessary to guarantee the quality of a fixed image.

When a color image is printed, a solid image is formed over a large area on the recording material P, especially for a photographic image. In this case, if the heating surface (the release layer 3) cannot follow the unevenness of the recording material or the unevenness of the toner layer, uneven heating occurs, and uneven gloss occurs in the image in portions where the amount of heat transfer is large and small. A portion having a large amount of heat transfer has a high gloss, and a portion having a small amount of heat transfer has a low gloss. When the thickness of the elastic layer 2 is 10 μm or less, the elastic layer 2 cannot follow the unevenness of the recording material or the toner layer, and the image gloss unevenness occurs. When the thickness of the elastic layer 2 is 1000 μm or more, the thermal resistance of the elastic layer becomes large and it is difficult to realize a quick start. More preferably, the thickness of the elastic layer 2 is 50 to
500 μm is preferred.

Even if the hardness of the elastic layer 2 is too high, the unevenness of the recording material or the toner layer cannot be completely followed, and image gloss unevenness occurs. Therefore, the hardness of the elastic layer 2 is 6
0 ° (JIS-KA type testing machine) or less, more preferably 45 ° or less.

The thermal conductivity λ of the elastic layer 2 is preferably 6 × 10 ⁻⁴ to 2 × 10 ⁻³ [cal / cm · sec · deg.].

The thermal conductivity λ is 6 × 10 ⁻⁴ [cal / cm · sec · de]
g.], the thermal resistance is large, and the temperature rise in the surface layer (release layer 3) of the fixing belt becomes slow.

The thermal conductivity λ is 2 × 10 ⁻³ [cal / cm · se
c · deg.], the hardness becomes too high or the compression set becomes worse.

Therefore, the thermal conductivity λ is 6 × 10 ⁻⁴ to 2 × 10
^-3 [cal / cm · sec · deg.] Is good. More preferably 8 × 10
^{−4 to} 1.5 × 10 ⁻³ [cal / cm · sec · deg.] Is good.

C. Release Layer 3 The release layer 3 is made of fluororesin, silicone resin, fluorosilicone rubber, fluororubber, silicone rubber, PFA, P
A material having good releasability and heat resistance, such as TFE and FEP, can be selected.

The thickness of the release layer 3 is preferably 1 to 100 μm. If the thickness of the release layer 3 is less than 1 μm, there arises a problem that uneven coating of the coating film causes a part having poor releasability or insufficient durability. In addition, when the release layer exceeds 100 μm, there is a problem that heat conduction is deteriorated. In particular, in the case of a resin release layer, the hardness becomes too high, and the effect of the elastic layer 2 is lost.

Further, as shown in FIG.
In the configuration described above, a heat insulating layer 4 may be provided on the free surface (the side opposite to the elastic layer 2 side) of the electromagnetic induction heat generating layer 1.

The heat insulating layer 4 is made of fluororesin, polyimide resin, polyamide resin, polyamideimide resin, PE
EK resin, PES resin, PPS resin, PFA resin, PT
A heat-resistant resin such as FE resin or FEP resin is preferable.

The thickness of the heat insulating layer 4 is 10 to 10
00 μm is preferred. When the thickness of the heat insulating layer 4 is smaller than 10 μm, the heat insulating effect cannot be obtained, and the durability is insufficient. On the other hand, if it exceeds 1000 μm, the magnetic core 17
In addition, the distance from the exciting coil 18 to the electromagnetic induction heating layer 1 increases, and the magnetic flux is not sufficiently absorbed by the electromagnetic induction heating layer 1.

The heat insulating layer 4 can insulate the heat generated in the electromagnetic induction heat generating layer 1 so as not to go to the inside of the fixing belt 10. Heat supply efficiency is improved. Therefore, power consumption can be suppressed.

B) Surface acoustic wave generating element 40 FIG. 10 shows the structure of the surface acoustic wave generating element 40.
(A) is a cross-sectional model diagram showing a layer configuration of the surface acoustic wave generating element 40, and (b) is a plan view showing an electrode pattern formed on the surface of the piezoelectric member 41.

The surface acoustic wave generating element 40 includes the piezoelectric member 4
1. It comprises electrodes 42, 43, 42 ', 43', an elastic layer 44, and a friction layer 45. The stacking order can be configured as shown in FIG.

The piezoelectric member 41 is made of a piezoelectric material such as lead zirconate titanate, barium titanate, and lead titanate. The electrodes 42.4 are placed on the piezoelectric member 41.
3, 42 'and 43' are printed.

The elastic layer 44 is made of, for example, silicone rubber,
Materials such as fluororubber and fluorosilicone rubber are preferred.

The friction layer 45 contacts the inner surface of the fixing belt 10 at the fixing nip N. As the friction layer 45,
Fluororesin, silicone resin, fluorosilicone rubber, fluororubber, silicone rubber, PFA, PTFE,
A material having good heat resistance such as FEP can be selected.

FIG. 11A shows how the piezoelectric member 41 expands and contracts when a voltage of (−) is applied to the electrode 42 and a voltage of (+) is applied to the electrode 43. That is, when the piezoelectric member 41 is attached to the elastic body 44, the elastic body 44 is bent such that the side on which the piezoelectric member 41 extends becomes a valley and the side on which the piezoelectric member 41 contracts becomes a mountain.

Electrodes 42 and 43 of surface acoustic wave generating element 40
FIG. 11 (b) shows a state when an AC voltage is applied to. That is, depending on the polarity of the AC voltage, the elastic body 44 has a flexure 44a and a flexure 44b which is inverted, and a wave having substantially the same shape as the applied voltage is generated in the elastic body 44 and the friction layer 45.

Here, the first power supply 47 supplies the electrode 42
The AC voltage applied to 43 is sin ωt (FIG. 12A)
First, the AC voltage applied from the power supply 47 ′ to the electrodes 42 ′ and 43 ′ is −cos ωt (FIG. 12B). That is, the AC voltage applied to the electrodes 42 ′ and 43 ′ is advanced by 90 ° from the AC voltage applied to the electrode electrodes 42 and 43. As a result, as shown in FIG.
_0, t _1, 2 two standing waves every time t ₂ are combined,
The synthesized standing wave becomes a traveling wave that progresses with time.

[0098] The traveling wave of the X-axis direction, as shown in (b) of FIG. 11, one point of the elastic body 44, Egaki direction of travel of the traveling wave (F ₁ direction) the opposite direction of the elliptical locus fixing belt 10 is opposite to the direction of travel of the traveling wave (F ₂ direction)
Moved to.

The belt guide member 16a and the surface acoustic wave generating element 40 are preferably fixed with a heat-resistant adhesive. In this case, as shown in FIG. 13, an elastic layer 46 may be interposed between the belt guide member 16a and the surface acoustic wave generating element 40. Further, it is also possible to substitute the elastic layer 46 with an adhesive.

By providing the elastic layer 46 between the belt guide member 16a and the surface acoustic wave generating element 40, the vibration generated by the surface acoustic wave generating element 40 is absorbed, and the surface acoustic wave generating element 40 is connected to the belt guide member 16a. It is possible to fix to.

The structure of the surface acoustic wave generating element 40 is such that the elastic body 44 and the electrodes 42 and 4 are arranged from the side of the belt guide member 16a.
3, the piezoelectric members 41 may be laminated in this order. Piezoelectric member 41
A friction layer 45 can be provided on the top.

The applied high frequency is preferably 20 kHz or more outside the audible range. In this example, a high frequency drive power supply
A high frequency voltage of kHz to several hundred MHz can be applied.

As described above, conventionally, heat-resistant grease was applied as a lubricant to the inner surface of the fixing belt 10 in order to reduce the mutual sliding frictional force on the surface of the fixing nip.
In this example, no heat-resistant grease is required, and the fixing belt 10
The fixing belt 10 can be rotated without affecting the life of the fixing belt 10.

Further, as compared with the case where the fixing belt 10 is driven by the frictional force with the pressure roller 30, the fixing belt 10 is directly driven, so that the paper can be stably conveyed without causing a slip.

Further, the fixing belt 10 is
Is driven, the elastic layer 30b of the pressure roller 30 thermally expands, so that the diameter of the pressure roller changes and the fixing nip portion N
However, in the present invention, since the fixing belt 10 is directly driven, it is not affected by the change in the conveying speed due to the thermal expansion of the pressure roller 30 in the present invention. The conveying speed of the recording material nipped and conveyed in the fixing nip portion N can be kept constant.

Conventionally, when the temperature of the heat-resistant grease is low, such as when the apparatus is started, sufficient lubricity cannot be obtained due to the high viscosity of the heat-resistant grease. Although the P and the pressure roller 30 may slip, such a slip can be prevented in this example. Moreover, since the durability does not deteriorate unlike the heat-resistant grease, the life of the device can be further extended.

<Second Embodiment> (FIG. 14) In this embodiment, the surface acoustic wave generating element 40 is provided on the piezoelectric member 41 in the surface acoustic wave generating element 40 of the first embodiment. The electrode 42 printed like
43, the first and second split electrode portions I (42a, 43a, 42a) in the longitudinal direction of the piezoelectric member 41 as shown in FIG.
a'.43a '). II (42b.43b, 42b'.4)
3b '), and the other configuration is the same as that of the first embodiment.

The electrodes 42a and 43 of the first divided electrode portion I
a, 42a 'and 43a' have high-frequency power sources 47a, respectively.
-47b is connected. Further, high-frequency power supplies 47a 'and 47b' are connected to the electrodes 42b and 43b and the electrodes 42b 'and 43b' of the second divided electrode section II, respectively.

In this embodiment, the high frequency power supplies 47a and 47a 'are variable in frequency, and the high frequency power supplies 47b and 47b' are fixed in frequency.

In this embodiment, the belt shift is detected by attaching a belt shift detecting device 51 to the end of the fixing belt. The detected belt shift amount is converted into a signal, and the control unit 52 sends the signals from the high-frequency power supplies 47a and 47a 'to the electrodes 42a, 43a and 42a' of the first divided electrode unit I in accordance with the shift amount.
The frequency of the applied voltage applied to 43a 'is controlled.

For example, when the fixing belt 10 is shifted downward X in FIG. 14, the high-frequency power supplies 47b and 47b '
Higher than the frequency of the applied voltage.
By increasing the frequency of the applied voltage, the fixing belt 10
In the fixing belt 10, the belt portion corresponding to the first divided electrode portion I of the fixing belt is faster than the belt portion corresponding to the second divided electrode portion II, and the fixing belt 10 has a conveying speed of FIG. Upper Y which is the fast belt part side of
Moved back to

Conversely, when the fixing belt 10 is shifted upward Y in FIG. 14, the frequency of the applied voltage of the high-frequency power supplies 47a and 47a 'is made lower than the frequency of the applied voltage of the high-frequency power supplies 47b and 47b'. With respect to the conveyance speed of the fixing belt 10, the belt portion corresponding to the second divided electrode portion II of the fixing belt is faster than the belt portion corresponding to the first divided electrode portion I, and the fixing belt 10 14
Is moved back to the lower part X which is the side of the belt portion where the conveying speed is fast.

As described above, by controlling the deviation of the fixing belt 10, the fixing belt 10 can be stably rotated without applying a load to the end of the fixing belt.

Since the deviation of the fixing belt 10 can be controlled, the fixing belt end regulating and holding flange members (holding rings) 23a and 23b disposed at the ends of the belt guide assemblies 16a and 16b can be omitted. .

<Third Embodiment> (FIG. 15) In this embodiment, the surface acoustic wave generating element 40 is provided on the piezoelectric member 41 in the surface acoustic wave generating element 40 of the first embodiment. The electrode 42 printed like
As shown in FIG. 15, the first, second, and third divided electrode portions I (42c, 43) are connected to the piezoelectric member 41 in the longitudinal direction.
c, 42c ', 43c'). II (42d, 43d, 42
d '43d') III (42e 43e, 42e '
43e '), and the other configuration is the same as that of the first embodiment.

The electrodes 42c, 43c and 42e of the first and third divided electrode portions I and III at both ends in the longitudinal direction of the piezoelectric member 41.
43e, electrodes 42c 'and 43c' and 42e 'and 43
e 'is connected to a common high-frequency power supply 47c and 47c', respectively. The second portion at the center in the longitudinal direction of the piezoelectric member 41
Electrodes 42d and 43d and 42d 'and 43 of the split electrode part II
High frequency power supplies 47d and 47d 'are connected to d', respectively.

Regarding the frequency of the applied voltage of the high frequency power supply,
Assuming that the frequencies of the high-frequency power supplies 47c and 47c 'are ωc and the frequencies of the high-frequency power supplies 47d and 47d' are ωd, ωc <ω
The relationship of d is satisfied.

As a result, the conveying speed of the fixing belt 10 by the surface acoustic wave generating element 40 is reduced.
The center portion is faster than both end portions in the longitudinal direction, and a biasing force toward the central portion in the longitudinal direction of the surface acoustic wave generating element 40 is always generated with respect to the fixing belt 10. Therefore, stable rotation of the fixing belt 10 can be obtained.

As in this example, the surface acoustic wave generation element 40 has a higher frequency than the high frequency applied to the electrodes of the first and third divided electrode portions I and III at both ends in the longitudinal direction of the surface acoustic wave generation element 40. By increasing the frequency of the high frequency with respect to the electrodes of the second divided electrode portion II at the central portion in the longitudinal direction, a force is always generated in the fixing belt 10 toward the central portion in the longitudinal direction of the surface acoustic wave generating element 40. There is no need to perform belt shift control, and the shift control mechanism can be omitted, and the fixing belt end portion regulation holding flange members 23a and 23b can be omitted.

<Other Embodiments> 1) The fixing belt 10 of the electromagnetic induction heating type may have a configuration in which the elastic layer 2 is omitted in the case of heat fixing such as a monochrome or one-pass multicolor image. . The electromagnetic induction heating layer 1 may be formed by mixing a metal filler in a resin. It can also be a single-layer member of the electromagnetic induction heating layer.

2) The pressing member 30 is not limited to the roller body, but may be another member such as a rotating belt type.

In order to supply heat energy to the recording material also from the pressing member 30 side, a heating means such as electromagnetic induction heating is also provided on the pressing member 30 side to heat and control the temperature to a predetermined temperature. It can also be configured.

3) The present invention can be used not only for conveying an endless belt having electromagnetic induction heat generation but also for improving the slidability of an endless belt using a linear heating element (such as a ceramic heater) as a heat source.

4) The heating device of the present invention is not limited to the image heating and fixing device of the embodiment, but may be an image heating device for heating a recording material carrying an image to improve the surface properties such as gloss, It can be widely used as a means or a device for heating a material to be heated, such as a heating device, a device for heating and drying a material to be heated, and a laminating device.

[0125]

As described above, according to the present invention,
A belt heating type heating device having a rotating endless belt and heating a member to be heated by heat from the belt side, an image heating device, and an electrophotographic apparatus / electrostatic recording device equipped with the heating device as an image heating device In such an image forming apparatus, a surface acoustic wave generating element is provided on a nip surface between an endless belt and a belt holding member, and the belt on the nip surface can be directly conveyed by generating a surface acoustic wave. For this reason, slippage of the material to be heated or the like with respect to the belt can be prevented. Further, the transport speed can be kept constant without being affected by the change in the transport speed due to the thermal expansion of the pressure roller. Further, by dividing the electrodes provided on the surface acoustic wave generating element in the longitudinal direction and adjusting the frequency of the high-frequency voltage applied to each electrode, the deviation of the belt can be controlled, and stable belt rotation can be obtained. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus used in a first embodiment.

FIG. 2 is a schematic cross-sectional side view of a main part of a fixing device as an image heating device.

FIG. 3 is a front view of the same main part.

FIG. 4 is a cross-sectional front view of the same main part.

FIG. 5 is a perspective model view of a belt guide member on the right side in which an excitation coil and a magnetic core are arranged and supported.

FIG. 6 is a diagram showing a relationship between a magnetic field generating means and a heating value Q;

FIG. 7 is a schematic diagram of a layer structure of a fixing belt having electromagnetic induction heating (part 1).

FIG. 8 is a graph showing a relationship between a heating layer depth and an electromagnetic wave intensity.

FIG. 9 is a schematic diagram of a layer structure of a fixing belt having electromagnetic induction heat generation (part 2).

FIG. 10 is a diagram illustrating the configuration of a surface acoustic wave generating element.

FIG. 11 is a schematic view showing a state of vibration of a surface acoustic wave generating element.

FIG. 12 illustrates generation of a traveling wave.

FIG. 13 is a schematic view showing a relationship between a belt guide member and a surface acoustic wave generating element.

FIG. 14 is an explanatory diagram of a configuration of a vibrating body in a second embodiment.

FIG. 15 is a configuration explanatory view of a vibrating body in a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heat generation layer 2 Elastic layer 3 Release layer 4 Heat insulation layer 10 Fixing belt 16a / 16b Belt guide member 17 Magnetic core 18 Exciting coil 19 Insulating member 23a / 23b Flange member for regulating / holding end of fixing belt 26 Temperature detecting element ( Thermistor) 30 Pressure roller as a pressure member 31 Drive roller 32 Tension roller 40 Surface acoustic wave generating element 41 Piezoelectric member 42, 42a to 42e, 43, 43a to 43e Electrode 44 Elastic layer 45 Friction layer 46 Elastic layer 47, 47a ~ 47d High frequency power supply

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenji Karashima 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Hideo Nanataki 3-30-2 Shimomaruko, Ota-ku, Tokyo Non-corporation F term (reference) 2H033 AA14 AA31 BA11 BB37 BE03 BE06

Claims (11)

[Claims] 1. A magnetic field generating means, an electromagnetic induction heat generating member which generates electromagnetic induction by the action of a magnetic field of the magnetic field generating means, and a nip portion of a member to be heated by mutual pressure contact with the electromagnetic induction heat generating member. A heating device for heating the member to be heated by the heat generated by the electromagnetic induction heating member by the magnetic field generated by the magnetic field generating means; the electromagnetic induction heating member is an endless belt; A heating device having a surface acoustic wave generating element on a surface facing a pressing member. 2. An endless belt, a supporting member for supporting the endless belt, and a pressing member for forming a nip portion by mutual pressure contact with the endless belt, a heating element in the endless belt, A heating device for heating a heating member, comprising a surface acoustic wave generating element on a surface of the endless belt facing a pressing member. 3. The heating device according to claim 1, wherein the surface acoustic wave generating element comprises at least a piezoelectric member, an electrode provided on the piezoelectric member, and an elastic layer.
A heating device characterized by applying a high-frequency voltage of 0 kHz or more. 4. A heating apparatus according to claim 3, wherein said surface acoustic wave generating element has a sliding layer on a contact surface with an endless belt. 5. The heating device according to claim 3, wherein the electrode is divided into a plurality of parts in a longitudinal direction of the surface acoustic wave generating element, and a high-frequency voltage is applied to each electrode. Heating equipment. 6. The heating device according to claim 5, wherein said electrode is divided into two in the longitudinal direction of the surface acoustic wave generating element, and a high-frequency voltage is applied to each electrode. 7. The heating device according to claim 3, further comprising a detecting means for detecting a movement of the endless belt in a longitudinal direction, wherein the detecting means detects a movement of the endless belt obtained from the detecting means. A heating device for changing the amplitude of the high-frequency voltage. 8. The heating apparatus according to claim 5, wherein said electrodes are divided into three in the longitudinal direction of the surface acoustic wave generating element, and a high-frequency voltage is applied to each electrode. 9. The heating device according to claim 8, wherein the amplitude of the voltage applied to the central divided electrode is larger than the amplitude of the voltage applied to the divided electrodes at both ends. 10. An image heating apparatus for heating an image on a recording material, wherein the image heating means is the heating apparatus according to claim 1. Description: 11. An image forming means for forming an image on a recording material, and an image heating means for heating an image formed on the recording material, wherein the image heating means is provided in any one of claims 1 to 9. An image forming apparatus, which is the heating apparatus according to any one of the preceding claims.