JPH11135246A - Heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abnormal temperature rising and improve maintenability by providing a temperature detecting element at a position facing a magnetic field generating means inside an electromagnetic induction heating member. SOLUTION: A temperature detecting element 21 is placed at a part facing an exciting coil 18 in a fixing film 10. Because temperature can be detected at a part facing a magnetic field generating means where temperature of the fixing film 10 is highest, accurate temperature detection can be performed. A fixing device 100 other than a magnetic field generating member 15 is provided such that it can be drawn from an image forming device body. Therefore, because in the condition that the fixing device 100 is drawn the facing part to the magnetic field generating member is exposed, heated material wound around the fixing film 10 can be easily removed. As a result, because no process for removing the magnetic field generating member 15 is required during exchanging of the fixing device 100, operability can be improved and operation time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic (magnetic) induction heating type heating apparatus and an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus having the heating apparatus as an image heating apparatus.

[0002]

2. Description of the Related Art For convenience, an image heating apparatus (fixing apparatus) for heating and fixing a toner image on a recording material 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 transferred to an appropriate image forming process means such as an electrophotographic process, an electrostatic recording process, or 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. In recent years, a film heating type device which is advantageous for saving energy and shortening a wait time has been put to practical use. Similarly, an electromagnetic induction heating system has been proposed.

Japanese Utility Model Laid-Open Publication No. 51-109736 discloses an induction heating fixing device in which current is induced in a fixing roller by magnetic flux and heat is generated by Joule heat. This achieves a more efficient fixing process than a heat roller type fixing device using a halogen lamp as a heat source by directly generating heat in the fixing roller by utilizing the generation of an induced current.

However, since the energy of the alternating magnetic flux generated by the exciting coil as the magnetic field generating means is used to raise the temperature of the entire fixing roller, heat dissipation is large, and the density of fixing energy with respect to the input energy is low, resulting in poor efficiency. .

Therefore, in order to obtain the energy acting on the fixing at a high density, the excitation coil is brought closer to the fixing roller as a heating element, or the alternating magnetic flux distribution of the excitation coil is concentrated near the fixing nip portion. An efficient fusing device has been devised.

FIG. 13 shows a schematic configuration of an example of an electromagnetic induction heating type fixing device in which the alternating magnetic flux distribution of the exciting coil is concentrated on the fixing nip to improve the efficiency.

Reference numeral 10 denotes a cylindrical fixing film having an electromagnetic induction heating layer (a conductor layer, a magnetic layer, and a resistor layer) and serving as an electromagnetic induction heating rotating body.

Reference numeral 16 denotes a film guide member having a trough-like shape having a substantially semicircular cross section. The cylindrical fixing film 10 is loosely fitted outside the film guide member 16.

Numeral 15 denotes a magnetic field generating means disposed inside the film guide member 16 and comprises an exciting coil 18 and an E-shaped magnetic core (core material) 17.

Numeral 30 denotes an elastic pressure roller, which forms a fixing nip portion N having a predetermined width with a predetermined pressing force with the lower surface of the film guide member 16 with the fixing film 10 interposed therebetween so as to be mutually pressed. The magnetic core 17 of the magnetic field generating means 15 is disposed at a position corresponding to the fixing nip N.
The pressing roller 30 is driven to rotate in the counterclockwise direction indicated by the arrow by the driving means M. A rotational force acts on the fixing film 10 by a frictional force between the pressing roller 30 and the outer surface of the fixing film 10 due to the rotational driving of the pressing roller 30, and the fixing film 10 moves the inner surface of the fixing film 10 in the fixing nip portion N. The outer periphery of the film guide member 16 is rotationally driven in a clockwise direction indicated by an arrow at a peripheral speed substantially corresponding to the rotational peripheral speed of the pressure roller 30 while sliding in close contact with the lower surface of the guide member 16 (pressure roller drive). method).

The film guide member 16 pressurizes the fixing nip N, and an exciting coil 18 as a magnetic field generating means 15.
And supports the magnetic core 17, supports the fixing film 10, and improves the transport stability when the film 10 rotates. The film guide member 16 is an insulating member that does not hinder the passage of magnetic flux, and is made of a material that can withstand a high load.

The temperature of the fixing nip N is determined by the pressure roller 30
The temperature is controlled by the temperature detecting means 26 brought into contact with the coil and the current supply to the exciting coil 18 is controlled based on the detected temperature to maintain a predetermined temperature.

Thus, the pressure roller 30 is driven to rotate,
Accordingly, the cylindrical fixing film 10 rotates around the film guide member 16, and the power is supplied from the excitation circuit to the excitation coil 18 to generate the electromagnetic induction heat of the fixing film 10 as described above. The recording material P on which the unfixed toner image t has been formed by the image forming unit (not shown) in the state where the temperature has risen to
Are the fixing film 10 in the fixing nip portion N and the pressure roller 3
0, the image surface is directed upward, that is, opposed to the fixing film surface, and the image surface is sandwiched in a state where the image surface is in close contact with the outer surface of the fixing film 10, and together with the fixing film 10 in the fixing nip portion N. Is transported. In the process of being transported through the fixing nip N, the unfixed toner image t on the recording material P is heated and fixed by being heated by the electromagnetic induction heating of the fixing film 10. The recording material P is a fixing nip N
, The sheet is separated from the outer surface of the rotary fixing film 10 and discharged and conveyed.

Japanese Patent Application Laid-Open No. 7-295414 discloses a configuration in which an electromagnetic induction heating member (magnetic field generating means) is provided outside a cylindrical rotary heating member.

Further, Japanese Patent Application Laid-Open No. 7-319312 discloses a configuration in which a magnetic field generating means is provided inside a cylindrical rotating heat generating member and a temperature detecting element is provided in a heat generating opposing portion thereof.

[0017]

Problems to be Solved by the Invention Japanese Patent Laid-Open No. 7-29541
In the electromagnetic induction heating device disclosed in Japanese Patent Application Publication No. 4 (1994), since the temperature detecting sensor is provided outside the heat generating portion, when the rotating heat generating member stops rotating for some reason, the temperature in the heat generating portion abnormally rises. May not be detected, which may result in damage to the device.

Further, when the material to be heated is wound around the rotary heating member, it may be difficult to remove the material to be heated.

Further, in the electromagnetic induction heating apparatus disclosed in Japanese Patent Application Laid-Open No. 7-319312, a method is adopted in which a safety device such as a thermostat is provided at an external heat-facing portion of an electromagnetic induction heating member to prevent runaway of the apparatus. ing. However, a rubber layer or a release layer (a fluororesin layer in the publication) is generally formed on the outer peripheral surface of the electromagnetic induction heating member. Since the air layer and the rubber layer and / or the release layer exist between them, the response speed of the safety device is reduced with respect to the heating speed of the heating member, and the member itself due to a rapid rise in temperature of the electromagnetic induction heating member May cause damage.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heating apparatus which solves problems caused by electromagnetic induction heating, such as prevention of abnormal temperature rise and improvement of maintainability, and an image forming apparatus using the same.

In particular, by providing the magnetic field generating means outside the electromagnetic induction heat generating member and providing the temperature detecting element inside the electromagnetic induction heat generating member at a position facing the magnetic field generating means, high accuracy can be achieved. It is an object of the present invention to provide a heating device and an image forming apparatus that enable temperature detection and prevent damage to the apparatus due to abnormal temperature rise.

Further, the magnetic field generating means is provided outside the electromagnetic induction heat generating member, and the electromagnetic induction heat generating member and the magnetic field generating means are relatively movable, so that the member to be heated can be easily wound. It is an object of the present invention to provide a heating apparatus and an image forming apparatus which can be easily removed and have improved maintainability.

[0023]

[Means for Solving the Problems]

[1]: having a magnetic field generating means, and an electromagnetic induction heating member that generates heat by the action of the magnetic field of the magnetic field generating means, wherein the magnetic field generating means is provided outside the electromagnetic induction heating member; A heating device for heating a material to be heated by heat generated by a member, wherein a temperature detecting element is provided inside the electromagnetic induction heating member at a position facing the magnetic field generating means.

[2]: having a magnetic field generating means, and an electromagnetic induction heating member which generates heat by the action of the magnetic field of the magnetic field generating means, wherein the magnetic field generating means is provided outside the electromagnetic induction heating member; A heating device for heating a material to be heated by heat generated by an induction heating member, wherein the electromagnetic induction heating member and the magnetic field generating means are provided so as to be relatively movable.

[3] The heating device according to [2], wherein a temperature detecting element is provided inside the electromagnetic induction heating member at a position facing the magnetic field generating means.

[4]: A temperature detecting heat generating member for generating heat by the action of the magnetic field of the magnetic field generating means and a temperature member for detecting the temperature of the heat generating member are provided outside the electromagnetic induction heat generating member. The heating device according to [2], which is characterized in that:

[5] The heating apparatus according to any one of [1] to [4], further comprising a gap holding member for maintaining a gap between the magnetic field generating means and the electromagnetic induction heating member. A heating device, characterized in that:

[6] The heating device according to any one of [1] to [5], wherein the electromagnetic induction heating member is a film-shaped member.

[7] The heating device according to [6], wherein a flange member is provided on one or both sides of the film-like electromagnetic induction heating member, and the flange member is a gap holding member. Heating equipment.

[8] The heating device according to any one of [1] to [7], further comprising a pressing member that forms a nip portion by mutually press-contacting the electromagnetic induction heating member. A heating device for heating a material to be heated introduced into a nip portion.

[0031]

[9]: an image forming means for forming a developer image on the recording material, and an image heating means for performing heat treatment using the recording material on which the developer image is formed as a material to be heated; An image forming apparatus comprising the heating device according to any one of [1] to [8] as image heating means.

[10]:

The image forming apparatus according to [9], wherein the image heating unit is attached to the image forming apparatus main body so that at least the magnetic field generating unit can be pulled out while being left on the image forming apparatus main body side. Image forming device.

[Operation] By installing the magnetic field generating means outside the rotating heat generating member and by installing the temperature detecting element inside the rotating heat generating member at the opposed portion of the magnetic field generating means, the magnetic field generating means can be arranged close to or in contact with the heat generating member. It is possible to detect the temperature of the heat generating member with high response speed and high accuracy, and it is possible to prevent the rotary heat generating member from being damaged or an accident.

[0034] By making the magnetic field generating means installed outside the electromagnetic induction heating member movable with respect to the heating member, the surroundings of the heating member can be removed at the time of processing (jam removal) work such as removing a member to be heated wound around the heating member. Since a work space can be opened to the user, jam clearance for a user or the like can be easily performed, and damage to members due to work is less likely to occur.

[0035] Equipped with a gap holding member to keep the gap between the magnetic field generating means and the heat generating member at an arbitrary distance, so that even when the magnetic field generating means is movably installed outside the heat generating member, an arbitrary gap is always secured during device operation Therefore, a desired efficiency can always be obtained.

[0036] By using the flange members at both ends of the film-shaped rotating heat generating member as the gap holding member, the gap between the magnetic field generating means and the heat generating member can be maintained at an arbitrary distance while suppressing the deviation and deformation of the film member. And a reduction in the number of parts and cost can be realized.

[0037] By providing the magnetic field generating means in the image forming apparatus main body, it is possible to perform maintenance without removing the magnetic field generating means unnecessary for the maintenance from the apparatus main body at the time of maintenance when replacing the unit including the jam processing and the electromagnetic induction heating member. It is possible to reduce the work required for maintenance and to reduce the parts damage rate due to replacement work.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION

(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 carrier) 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.
Scan exposure processing of the target image information. The laser optical box 110 is a laser beam 103 modulated (on / off) corresponding to a time-series electric digital pixel signal of target image information from an image signal generator such as an image reader (not shown).
Is output to scan and expose the surface of the rotating photosensitive drum 101 to form an electrostatic latent image corresponding to the target image information on the surface of the drum 101. A mirror 109 deflects the output laser beam 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 transferred to the surface of the intermediate transfer drum 105 at a primary transfer portion T1 which is a contact portion (or a close portion) between the photosensitive drum 101 and the intermediate transfer drum 105. The intermediate transfer drum 105 has a medium-resistance elastic layer and a high-resistance surface layer on a metal drum,
The photosensitive drum 101 is rotated in the clockwise direction as indicated by an arrow at substantially the same peripheral speed as the photosensitive drum 101 in contact with or in proximity to the photosensitive drum 101, and is supplied with a bias potential. Is transferred to the surface of the intermediate transfer drum 105.

After the transfer of the toner image to the surface of the intermediate transfer drum 105, the surface of the rotating photosensitive drum 101 is
At 07, cleaning is performed by removing attached residues such as transfer residual toner.

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

The color toner image is supplied to the secondary transfer unit T2 from a paper supply unit (not shown) at a secondary transfer unit T2 which is a contact nip between the rotary intermediate transfer drum 105 and the transfer roller 106. Is transferred onto the surface of the recording material P fed in at the timing of (1). The transfer roller 106 supplies a charge having a polarity opposite to that of the toner from the back surface of the recording material P, and collectively transfers the composite color toner image from the surface of the intermediate transfer drum 105 to the recording material P.

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. The fixing device 100 will be described in detail in the following section (2).

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

The transfer roller 106 is 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 this embodiment can also execute a print mode of a mono-color image such as a self-black 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 printed.
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.

In the present embodiment, the toner containing a low softening substance is used.

(2) Fixing Device (Heating Means) 100 FIG. 2 is a schematic cross-sectional view of a main part of the fixing device 100 of the present embodiment, and FIG. 3 is a front model view of the main part (an external magnetic field generating member is omitted). The device of this example is a pressure roller driving type / electromagnetic induction heating type device using a cylindrical electromagnetic induction heat-generating film, like the fixing device of FIG.

2a) Overall Configuration of Fixing Device 100 In FIGS. 2 and 3, reference numeral 10 denotes a cylindrical fixing film as an electromagnetic induction heating member, and a heating layer which generates heat by the action of a magnetic field as a base layer as described later. It has a laminated structure having an elastic layer and a release layer on its outer periphery. Reference numeral 16 denotes a film guide member having a substantially semicircular cross section, and the cylindrical fixing film 10 is loosely fitted to the outside. Reference numeral 22 denotes a horizontally long pressing rigid stay disposed above the film guide member 16, and both ends thereof and the fixing device cover 40a,
The pressing force of the pressing springs (pressing means) 25a and 25b contracted between the film guide member 16 and the spring support portion 40c of the 40b is transmitted to the film guide member 16. Reference numerals 23a and 23b denote flange members which are externally fitted to both ends in the longitudinal direction of the film guide member 16 and whose positions in the longitudinal direction are fixed and rotatably mounted to regulate and hold the ends of the fixing film 10.
The flange members 23a and 23b
Are coupled with the fixing film 10 to rotate together with the fixing film 10 and maintain the fixing film 10 in a cylindrical shape, thereby preventing the fixing film 10 from moving right and left and from being damaged.

Numeral 15 denotes a magnetic field generating means disposed outside the film guide member 16 and comprises an exciting coil 18 and an E-shaped magnetic core (core material) 17. Reference numeral 21 denotes a temperature detecting element for detecting the temperature of the fixing film 10, which means a thermistor for controlling temperature, a fuse / thermostat for cutting off power supplied to a magnetic field generator, and the like.

Numeral 30 denotes an elastic pressure roller which presses the lower surface of the film guide member 16 mutually with a predetermined pressing force with the fixing film 10 interposed therebetween to form a fixing nip portion N. The pressure roller 30 is driven to rotate in a counterclockwise direction indicated by an arrow by a driving unit (not shown), and the rotation drive carries the recording material (heated material) P and drives the fixing roller 10 (pressing). Roller drive system).

Thus, the pressure roller 30 is driven to rotate,
Accordingly, the cylindrical fixing film 10 rotates around the film guide member 16, and the power is supplied to the exciting coil 18 to generate electromagnetic induction heat of the fixing film 10, and the fixing nip portion N rises to a predetermined temperature to control the temperature. In this state, the recording material P on which the unfixed toner image t is formed as described above has the image surface facing upward, that is, facing the fixing film surface, between the fixing film 10 and the pressure roller 30 in the fixing nip portion N. The fixing member 10 is transported while holding the image surface in close contact with the outer surface of the fixing film 10, and in this process, the unfixed toner image t is heated on the recording material P by the electromagnetic induction heating of the fixing film 10. Fix it. When the recording material P passes through the fixing nip portion N, the rotating fixing film 10
The sheet is separated and transported from the outer surface of the sheet.

2b) Principal Parts of the Fixing Device 100 In the present embodiment, the magnetic core 17 has an E-shaped cross section, and the coil 18 is incorporated in the recess. The magnetic field generating member 15 including the magnetic core 17 and the coil 18 is fixedly supported by the image forming apparatus main body in a state of being close to the fixing film 10 by the support member 20.

The fixing film 10, the film guide member 16, and the pressure roller 3, excluding the magnetic field generating member 15,
0, a fixing unit 100a including the fixing device covers 40a and 40b is provided so as to be able to be pulled out from the image forming apparatus main body. Thus, when the fixing unit 100a is pulled out, the portion of the fixing unit 100a facing the magnetic field generating member is exposed, so that the heating target material wound around the fixing film 10 can be easily removed.

Further, by adopting a configuration in which the cover member (not shown) covers the magnetic field generating member facing portion when the fixing unit 100 is pulled out, careless damage to the fixing unit can be prevented.

Further, by adopting such a configuration, it is not necessary to remove the magnetic field generating member when exchanging the fixing unit, so that the maintainability (workability and work time, etc.) can be improved.

In addition, the supporting member 20 is fixed to the fixing unit 1.
The same effect as the above-described configuration can be obtained by installing on the 00a side and making the heating member 10 movable.

Further, in the present embodiment, the temperature detecting element 21 is installed in a portion facing the magnetic field generating coil 18 inside the heat generating member 10 so that the temperature detecting element 21 and the heat generating member 10 are in a non-contact state. It can be installed in a contact state for the purpose of improving responsiveness and accuracy.

By arranging the temperature detecting element 21 inside the fixing film 10 and at the portion facing the magnetic field generating means as described above, the temperature is detected at the portion facing the magnetic field generating means at which the temperature of the fixing film 10 becomes the highest. As a result, the temperature can be accurately detected.

Further, in this embodiment, a gap holding member is provided on the support member 20 side or the fixing film 10 side of the magnetic field generating member 15 to always maintain the gap (interval) L between the magnetic field generating member 15 and the fixing film 10. I am trying to do it.

The closer the distance L between the magnetic field generating member 15 and the heat generating layer 1 of the fixing film 10 is to the extent possible, the higher the efficiency of absorbing magnetic flux. In particular, the distance L is 5 mm.
When the ratio exceeds, the efficiency is remarkably reduced. If the distance is within 5 mm, the interval L between the heating layer of the fixing film 10 and the exciting coil 18 does not need to be constant.

In this embodiment, the flange members 23a, 23a
3b is a gap holding member, and as shown in FIG. 5, its outer peripheral portion is brought into contact with a roller member 24 provided on the support member 20 to maintain a gap L during operation. (Only the flange member 23a side is shown in FIG. 5, but the opposite side is also the same (laterally symmetric).) Thus, by using the flange members (gap holding members) 23a and 23b, the magnetic field generating member 15 The distance L between the fixing film 10 and the magnetic field generating member 15 can be appropriately maintained even when the fixing member 10 is moved with respect to the fixing film 10.

2c) Details of the Heating Apparatus 100 Next, the magnetic core 17, which will be described for each element constituting the apparatus of this embodiment, is a member having a high magnetic permeability, and is preferably made of a material used for a transformer core such as ferrite or permalloy.
It is more preferable to use a ferrite with less loss even at 100 kHz or more.

The pressure roller 30 is composed of a core metal 30a and a heat-resistant and elastic material layer 30b of silicone rubber, fluoro rubber, fluoro resin, or the like, which is formed and coated concentrically around the core in a roller shape. Both ends of the cored bar 30a are supported between chassis side plates (not shown) of the apparatus.

The pressure roller 30 is driven to rotate in a counterclockwise direction shown by an arrow in FIG. 2 by driving means (not shown). A rotational force acts on the fixing film 10 by a frictional force between the pressing roller 30 and the outer surface of the fixing film 10 due to the rotational driving of the pressing roller 80, and the fixing film 10 is fixed to the fixing nip portion N.
At the same time, the inner surface of the pressing roller 30 is rotated in a clockwise direction as indicated by an arrow while sliding in close contact with the lower surface of the film guide member 16.
Is rotated around the outer periphery of the film guide member 16 at a peripheral speed substantially corresponding to the rotational peripheral speed.

In this case, in order to reduce the mutual sliding friction between the lower surface of the film guide member 16 and the inner surface of the fixing film 10 in the fixing nip N, the lower surface of the film guide 16 in the fixing nip N and the A lubricant such as heat-resistant grease may be interposed between the inner surface and the lubricant, or the lower surface of the film guide member 16 may be covered with a lubricant. The film guide member 16 is
It serves to support the pressure applied to the fixing nip N and the fixing film 10 and to improve the transport stability of the film 10 during rotation.

16e (FIG. 4) is the film guide member 16
A plurality of lower film guide circumferential ribs are formed on the side surface of the film guide member at intervals along the length of the film guide member. The convex rib portion 16e functions to reduce the contact sliding resistance between the lower surface of the film guide member 16 and the inner surface of the fixing film 10, thereby reducing the rotational load of the fixing film 10.

The exciting coil 18 is connected to an exciting circuit (not shown). This excitation circuit can operate from 20 kHz to 50
A high frequency of 0 kHz can be generated 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.

2c-1. Excitation Coil 18 The excitation 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). It is wound to form an exciting coil.

As the insulating coating, a coating having heat resistance is preferably used in consideration of heat conduction due to heat generation of the fixing film 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.

The material of the film guide member 16 is as follows.
In order to secure insulation from the fixing film 10, it is preferable to use a film having excellent insulation properties and good heat resistance. 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, LCP
It is better to select a resin or the like.

2c-2. Fixing Film 10 FIG. 7 is a schematic diagram of the layer structure of the fixing film 10 in this example. The fixing film 10 according to the present embodiment includes a heating layer 1 having an electromagnetic induction heating function as a base layer, an elastic layer 2 laminated on the outer surface thereof,
It has a composite structure of the release layer 3 laminated on the outer surface.
For adhesion between the heat generating layer 1 and the elastic layer 2 and between the elastic layer 2 and the release layer 3, a primer layer (not shown) may be provided between each layer. In the fixing film 10 of this example having such a layer configuration and having a cylindrical shape, the heat generating layer 1 is on the inner surface side, and the release layer 3 is on the outer surface side. As described above, the heating layer 1
When an alternating magnetic flux acts on the heat generating layer 1, an eddy current is generated in the heat generating layer 1 and the heat generating 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. Heating Layer 1 The heating layer 1 may be made of a non-magnetic 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. 7).

Therefore, the thickness of the heat generating layer 1 is preferably 1 to 1
00 μm is preferred. If the thickness of the heat generating layer 1 is smaller than 1 μm, most of the electromagnetic energy cannot be absorbed, so that the efficiency is deteriorated. On the other hand, if the heat generating layer 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 heat generating layer 1 is preferably 1 to 100 μm.

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.

Further, even if the hardness of the elastic layer 2 is too high, the elasticity of the elastic layer 2 cannot follow the irregularities of the recording material or the toner layer, resulting in uneven image gloss. Therefore, the hardness of the elastic layer 2 is 6
0 ° (JIS-A) or less, more preferably 45 ° (JIS-A)
SA) The following is preferred. 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 film 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.

In this embodiment, the electromagnetic induction coil 1 is used.
Although the configuration in which the core 17 is arranged around the 8 has been described, the core 17 is not always necessary.

(3) Effects of the present embodiment As described above, according to the present embodiment, the fixing unit 100a is provided so as to be able to be pulled out from the image forming apparatus main body while the magnetic field generating member 15 is left on the image apparatus main body side. This facilitates the process of removing the heating target material P wound around the fixing film 10.

The supporting member 20 is fixed to the fixing unit 100.
a fixing film (heating member) 10
It is also possible to obtain the same effect as the above configuration by making it movable with respect to.

Further, in the present embodiment, the temperature detecting element 21 is provided in a portion facing the magnetic field generating coil 18 inside the heat generating member 10 to enable accurate temperature detection. The heating member P is prevented from being hindered from being removed, and the temperature can be detected even when the fixing film 10 suddenly stops.

Further, in this embodiment, the gap holding member 2
With the provision of 3a and 23b, even when the magnetic field generating member 15 is moved from a predetermined position near the fixing film to remove the recording material P, and then the magnetic field generating member is returned to the predetermined position, The magnetic field generating member 15 and the fixing film 1
This makes it possible to keep an appropriate distance from zero, thereby preventing heat generation efficiency from deteriorating due to the movement.

<Second Embodiment> FIG.
This is an example of an embodiment in which a roller is used as a heat generating member of No. 0. 2, 3 and 13, the same reference numerals are given to the same components and portions as those in FIGS. 2, 3, and 13, and the description thereof will not be repeated. Do.

In this embodiment, the magnetic field generating member 15 composed of the magnetic core 17 and the coil 18 is
And is installed outside the fixing roller 10 as a heat generating member.

The fixing roller 10 has substantially the same layer structure as that of the film as shown in FIG. 9, but in this embodiment, the roller itself is made of a rigid body, and is brought into pressure contact with the pressure roller 30 so as to have a predetermined nip pressure. Is to be obtained. As the heat generating layer 1 of the fixing roller 10, a ferromagnetic metal such as ferromagnetic SUS or nickel-cobalt alloy is suitable.

As described above, since the roller itself is made rigid, there is no fear of deformation, so that the film guide member 16, the stay 22, the flange member 23a, and the like as shown in the first embodiment.
23b and the like become unnecessary, and the number of parts can be reduced and the structure can be simplified.

Since the fixing roller 10 is rigid, the fixing roller itself can be driven by driving means such as a gear or a belt (not shown).

In this embodiment, the temperature detecting element 21 is
The heat generating layer 1 is in contact with the heat generating layer 1. Further, by using the rigid fixing roller 10, a roller-shaped gap holding member or the like is provided on the support member 20 side, and is abutted against the fixing roller 10 side, so that the fixing roller (heating member) can be easily formed.
The distance L between the magnetic field generating member 15 and the magnetic field generating member 15 can be maintained at an arbitrary distance. In this example, the roller-shaped gap holding member 24 is pressed against the surfaces of the rigid portions at both ends of the roller that are not covered with the elastic layer 2 and the release layer 3 so as to maintain an arbitrary distance with higher accuracy.

However, it is also possible to press the gap holding member 24 against the elastic layer 2 or the release layer 3 to maintain an arbitrary distance.

In this embodiment, the electromagnetic induction coil 1 is used.
Although the configuration in which the core 17 is arranged around the 8 has been described, the core 17 is not always necessary.

<Third Embodiment> FIG. 11 is a schematic structural view of a third embodiment according to the present invention. In this embodiment,
Since the support member 20 is installed on the fixing device 100 side and the other configuration is the same as that of the second embodiment, the same elements are denoted by the same reference numerals and the description thereof will not be repeated. ing.

In this embodiment, the support member 20 is rotatably supported by the fixing device upper cover 40a by the support shaft 55 and the like. The fixing device 100 including the magnetic field generating member 15 can be integrally removed from the image forming apparatus main body. It is configured to be able to.

When the magnetic field generating member 15 is displaced from the position facing the fixing film during the heating operation, the not-shown butting mechanism is released, and the magnetic field generating member 15 is rotated upward about the support shaft 55 (arrow). direction). With this operation, a space is created in the heat-generating member-facing portion where the magnetic field generating means has been installed, so that the material to be heated or the like wrapped around the heat-generating member can be easily removed.

In this embodiment, the electromagnetic induction coil 1 is used.
Although the configuration in which the core 17 is arranged around the 8 has been described, the core 17 is not always necessary.

<Fourth Embodiment> FIG. 12 is a schematic structural view of a fourth embodiment according to the present invention.

The present embodiment is different from the third embodiment in that the temperature detecting element 21 is provided inside the support member 20 outside the fixing roller 10, and the other configuration is the same.

In this embodiment, a heating member 56 for temperature detection is provided separately from the fixing roller 10 in the support member 20 of the magnetic field generating means 15 on the side opposite to the fixing roller 10.
The temperature detecting element 21 is provided in the support member 20 on the side opposite to the magnetic field generating means 15. Note that the support member 20 may be installed on the image forming apparatus main body side.

The heat generating member 56 and the temperature detecting element 21
Need not necessarily be installed in the support member 20 and may be installed on the image forming apparatus main body side without any problem.

With this configuration, it is possible to reduce the diameter of the fixing roller 10 and to simplify the internal structure of the fixing roller 10.

[0114]

As described above, according to the present invention,
It is possible to provide a heating device that solves problems caused by electromagnetic induction heating, such as prevention of abnormal temperature rise and improvement in maintainability, and an image forming apparatus using the same.

In particular, by providing the magnetic field generating means outside the electromagnetic induction heat generating member and providing the temperature detecting element inside the electromagnetic induction heat generating member at a position facing the magnetic field generating means, high accuracy is achieved. It is possible to provide a heating device and an image forming apparatus capable of detecting temperature and preventing damage to the apparatus due to abnormal temperature rise.

Further, the magnetic field generating means is provided outside the electromagnetic induction heat generating member, and the electromagnetic induction heat generating member and the magnetic field generation means are relatively movable, so that the member to be heated can be wound. Can be easily removed, and a heating device and an image forming apparatus with improved maintainability can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention;

FIG. 2 is a schematic configuration diagram of a heating device according to the first embodiment.

FIG. 3 is a front view of the apparatus of FIG. 2;

FIG. 4 is a perspective view of a film guide member.

FIG. 5 is an explanatory view of a gap holding member.

FIG. 6 is a schematic diagram showing the layer structure of an electromagnetically induced heating fixing film.

FIG. 7 is a graph showing a relationship between a heating layer depth and an electromagnetic wave intensity.

FIG. 8 is a schematic configuration diagram of a second embodiment example.

FIG. 9 is a schematic diagram of a layer structure of a fixing roller having an electromagnetic induction heating property.

FIG. 10 is an explanatory view of a cap holding member when a roller is used.

FIG. 11 is a schematic configuration diagram of a third embodiment.

FIG. 12 is a schematic configuration diagram of a fourth embodiment.

FIG. 13 is a schematic configuration diagram of an example of a conventional electromagnetic induction heating type heating device (fixing device).

[Explanation of symbols]

 Reference Signs List 10 electromagnetic induction heating member (fixing film, fixing roller) 17 magnetic core 18 excitation coil 20 support member 21 temperature detecting element 30 pressing member (pressing roller) 100 heating device (fixing device) P heated object t developer image (Toner image)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tetsuya Sano 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (10)

[Claims] An electromagnetic induction heating member for generating heat by the action of a magnetic field of the magnetic field generation means, wherein the magnetic field generation means is provided outside the electromagnetic induction heating member; A heating device for heating a material to be heated by heat generated by a conductive member, wherein a temperature detecting element is provided inside the electromagnetic induction heating member at a position facing the magnetic field generating means. 2. An electromagnetic induction heating element comprising: a magnetic field generating means; and an electromagnetic induction heating member which generates heat by the action of a magnetic field of the magnetic field generation means, wherein the magnetic field generation means is provided outside the electromagnetic induction heating member. A heating device for heating a material to be heated by heat generated by a conductive member, wherein the electromagnetic induction heating member and the magnetic field generating means are provided so as to be relatively movable. 3. The heating apparatus according to claim 2, wherein a temperature detecting element is provided inside the electromagnetic induction heating member at a position facing the magnetic field generating means. 4. A heat detecting member for detecting temperature which generates heat by the action of a magnetic field of said magnetic field generating means and a temperature member for detecting a temperature of said heat generating member outside said electromagnetic induction heat generating member. The heating device according to claim 2. 5. The heating device according to claim 1, further comprising a gap holding member for keeping a gap between said magnetic field generating means and said electromagnetic induction heating member. Heating equipment. 6. The heating device according to claim 1, wherein the electromagnetic induction heating member is a film-shaped member. 7. The heating device according to claim 6, wherein a flange member is provided on one or both sides of the film-shaped electromagnetic induction heating member, and the flange member is a gap holding member. apparatus. 8. The heating device according to claim 1, further comprising: a pressure member that forms a nip portion by mutually press-contacting the electromagnetic induction heat-generating member, and is introduced into the nip portion. A heating device for heating a heated material to be heated. 9. An image forming means for forming a developer image on a recording material, and an image heating means for performing heat treatment using the recording material on which the developer image has been formed as a material to be heated, An image forming apparatus comprising the heating device according to claim 1 as the image heating means. 10. The image forming apparatus according to claim 9, wherein the image heating means is attached to the image forming apparatus main body so that at least the magnetic field generating means can be pulled out while being left on the image forming apparatus main body side. An image forming apparatus comprising: