JPH10240049A - Heating device and image forming device - Google Patents

Abstract

(57) Abstract: A heating apparatus and an image forming apparatus having a rotatable electromagnetic induction heat-generating member that generates electromagnetic induction heat by the action of a magnetic field of a magnetic field generating means while maintaining stable and good fixing performance. , Realizing a quick start and reducing power consumption. SOLUTION: The circumference of a rotating body 10 as an electromagnetic induction heating member that generates electromagnetic induction heat by the action of a magnetic field of a magnetic field generating means is set to 200 [mm] or less, and the time required for the rotating body to make one rotation is reduced. Within 3 [sec].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for pressurizing a material to be heated.
The present invention relates to a heating device for heating and an image forming apparatus such as an electrophotographic apparatus and an electrostatic recording device provided as an image heating device for heating and fixing an unfixed image in which the heating device is formed and carried on a recording material.

[0002]

2. Description of the Related Art For convenience, an image heating apparatus (fixing apparatus) provided in an image forming apparatus such as a copying machine or a printer for heating and fixing a toner image on a recording material 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 heat roller is used as a fixing device that heats and fixes an unfixed image (toner image) of the target image information formed on a printing paper or a format paper by a transfer method or a direct method as a permanently fixed image on a recording material surface. Type devices were widely used. Recently, a film heating type apparatus has been put into practical use. Also, an electromagnetic induction heating system has been proposed.

A) Heat roller type fixing device This is a fixing device which basically has a pressure roller pair of a fixing roller (heating roller) and a pressure roller, and rotates the roller pair to form a mutual pressure contact portion between the roller pairs. A recording material on which an unfixed toner image to be fixed is formed and carried is introduced into the fixing nip portion (heating nip portion), and the recording material is nipped and conveyed, and is not fixed by the heat of the fixing roller and the pressing force of the fixing nip portion. The toner image is fixed by heat and pressure on the surface of the recording material.

[0005] The fixing roller generally has a hollow metal roller made of aluminum as a base (core metal), and a halogen lamp as a heat source is inserted and disposed in the inner space thereof. The power supply to the halogen lamp is controlled to control the temperature so that the predetermined fixing temperature is maintained.

In particular, as a fixing device of an image forming apparatus for forming a full-color image, which is required to be capable of sufficiently heating and melting a maximum of four toner image layers to mix colors, a recording material, a toner image layer, If not sufficiently heated to the interface of the fixing roller, a fixing defect occurs.Therefore, the core of the fixing roller has a high heat capacity, and a rubber elastic layer is provided around the core to wrap the toner image and uniformly melt the toner image. Then, the toner image is heated through the rubber elastic layer. There is also a configuration in which a heat source is provided in the pressure roller to heat and control the temperature of the pressure roller.

However, in the heat roller type fixing device, even if the power of the image forming apparatus is turned on and the halogen lamp which is the heat source of the fixing device is energized at the same time, the heat capacity of the fixing roller is large and the fixing roller and the like are cooled. A considerable waiting time (wait time) is required from the cutting state to the rise to a predetermined fixable temperature, and the quick start property is lacking. Further, it is necessary to keep the fixing roller in a predetermined temperature control state by energizing the halogen lamp so that the image forming operation can be performed at any time even when the image forming apparatus is in a standby state (non-image output). There were problems such as a large amount.

In a fixing device having a particularly large heat capacity, such as the fixing device of the above-described full-color image forming apparatus, a delay occurs between the temperature control and the temperature rise on the surface of the fixing roller. Problems such as uneven gloss and offset have occurred.

B) Fixing device of the film heating type A fixing device of the film heating type is disclosed in, for example,
Japanese Patent Application Laid-Open No. 13182, Japanese Patent Application Laid-Open No. 2-1577878, Japanese Patent Application Laid-Open No. 4-44075, Japanese Patent Application Laid-Open No. 4-204980, and the like.

That is, a nip portion is formed by sandwiching a heat-resistant film (fixing film) between a ceramic heater as a heating element and a pressing roller as a pressing member. By introducing a recording material on which an unfixed toner image to be image-fixed is formed and carried between the pressure roller and holding and transporting the recording material together with the film, the heat of the ceramic heater is recorded via the film in the nip portion through the film. The unfixed toner image is heated and fixed on the surface of the recording material by applying pressure to the material and applying pressure at the nip portion.

This film heating type fixing device can be constituted as an on-demand type device using a ceramic heater and a member having a low heat capacity as a film, and a ceramic heater as a heat source only when the image forming apparatus executes image formation. To a state in which heat is generated to a predetermined fixing temperature, the waiting time from the power-on of the image forming apparatus to the image forming executable state is short (quick start property), and the power consumption during standby is greatly reduced. There are advantages such as small (power saving).

However, a full-color image forming apparatus requiring a large amount of heat or a fixing device for a high-speed model has a calorific point.

C) Fixing Device of Electromagnetic Induction Heating System JP-A-51-109739 discloses an induction heating fixing device in which current is induced in a fixing roller by magnetic flux to generate heat by Joule heat. This makes it possible to directly generate heat in the fixing roller by utilizing the generation of an induced current, and achieves a more efficient fixing process than a heat roller type fixing device using a halogen lamp as a heat source.

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. there were.

Therefore, in order to obtain a high density of energy that acts to fix the toner image on the surface of the recording material, the exciting coil is brought closer to the fixing roller, which is a heating element, or the alternating magnetic flux distribution of the exciting coil is changed to the fixing nip. A high-efficiency fixing device has been devised by concentrating in the vicinity.

FIG. 14 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 in the fixing nip portion 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 gutter-shaped cross section having a substantially semicircular arc shape, and 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.

Reference numeral 30 denotes an elastic pressure roller (hereinafter, referred to as a pressure roller) which forms a fixing nip portion N having a predetermined width with a predetermined pressing force against the lower surface of the film guide member 16 with the fixing film 10 interposed therebetween. The film is pressed against the film guide member 16 so as to be pressed.

The magnetic core 17 of the magnetic field generating means 15 is disposed at a position corresponding to the fixing nip portion N.

The pressure roller 30 is driven to rotate in a counterclockwise direction indicated by an arrow by a 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,
The fixing film 10 has a peripheral speed substantially corresponding to the rotational peripheral speed of the pressure roller 30 in the clockwise direction as indicated by the arrow while the inner surface of the fixing film 10 slides in the fixing nip portion N in close contact with the lower surface of the film guide member 16. The outer periphery of the member 16 is rotated (a pressure roller driving method).

The film guide member 16 is provided with an excitation coil 18 as a means for applying pressure to the fixing nip N and generating a magnetic field 15.
And the magnetic core 17, the fixing film 10, and the transport stability of the fixing film 10 during rotation. 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, for example, a temperature sensor 2 such as a thermistor for detecting the temperature of the pressure roller 30.
The temperature is controlled such that a predetermined temperature is maintained by controlling the current supply to the exciting coil 18 by a temperature control system (not shown) including the control unit 6.

Thus, the pressure roller 30 is driven to rotate,
Along with this, the cylindrical fixing film 10 rotates around the film guide member 16, and the power is supplied from the excitation circuit (not shown) to the excitation coil 18 so that the electromagnetic induction heating of the fixing film 10 is performed as described above, so that the fixing nip portion is formed. In a state in which the temperature of N has risen to a predetermined temperature and the temperature has been adjusted, the recording material P on which the unfixed toner image t formed from the image forming unit (not shown) is formed is fixed to the fixing film 1 in the fixing nip portion N.
0 and the pressure roller 30, the image surface is introduced upward, that is, is opposed to the fixing film surface, and at the fixing nip portion N, the image surface adheres to the outer surface of the fixing film 10 and is fixed together with the fixing film 10. The nip portion N is nipped and conveyed. In the process in which the recording material P is nipped and conveyed in the fixing nip portion N together with the fixing film 10, the unfixed toner image t on the recording material P is heated by the electromagnetic induction heating of the fixing film 10 so that the recording material P It is heat-fixed on the surface. When the recording material P passes through the fixing nip portion N, it is separated from the outer surface of the rotary fixing film 10 and discharged and conveyed.

[0026]

The electromagnetic induction type fixing device in which the fixing film generates heat as shown in FIG.
Although the alternating magnetic flux distribution of the excitation coil is concentrated in the fixing nip to improve the fixing efficiency, the fixing film with a small heat capacity is directly heated and rotated, and there is no heat source with a large heat capacity. However, the temperature of the fixing film decreases during one rotation of the fixing film, so that the fixing film is heated again, and a large amount of energy is required to compensate for the temperature drop, resulting in poor efficiency. There is a tendency that quick start cannot be performed because much time is required for heating.

This tendency is closely related to the circumference of the fixing film and the time required for the fixing film to make one rotation. That is, since the electromagnetic induction heating layer of the fixing film (electromagnetic induction heating member), which generates electromagnetic induction by the action of the magnetic field of the magnetic field generating means, is thin, the heat capacity is small and the heat dissipation is good. For this reason, if the circumference of the fixing film is made longer than necessary,
The temperature drop during one rotation of the fixing film becomes large, making it impossible to cope with the quick start, and increasing the heating area due to the increase in the circumference of the fixing film, thereby increasing power consumption. Further, the radius of curvature of the fixing film becomes large at both ends (upstream end and downstream end) of the fixing nip portion, so that stable fixing property cannot be ensured, and the durability of the fixing film is remarkably increased. It also causes deterioration. If the time required for one rotation of the fixing film is too long, the temperature drop during one rotation of the fixing film is large. I can no longer respond.

According to the present invention, there is provided the electromagnetic induction heating member which generates electromagnetic induction by the action of the magnetic field of the magnetic field generating means and the time required for the electromagnetic induction heating member to make one rotation. The present invention has been made in view of the above problems, and has an object to provide a heating device and an image forming apparatus capable of realizing quick start and reducing power consumption while securing stable and good fixing properties. I do.

[0029]

According to the present invention, there is provided a heating apparatus and an image forming apparatus having the following constitutions. [1]: a magnetic field generating means, an electromagnetic induction heat generating member which generates electromagnetic induction by the action of the magnetic field of the magnetic field generating means, and a heat generating member which forms a nip portion of the material to be heated by mutual pressure contact with the electromagnetic induction heat generating member. A heating member for heating the material to be heated in the nip portion by utilizing heat generated by the electromagnetic induction heating member, wherein the electromagnetic induction heating member is a rotating body, and A heating device having a circumference of 200 [mm] or less and a time required for the rotating body to make one rotation is within 3 [sec]. [2]: a magnetic field generating means, an electromagnetic induction heating member which generates heat by electromagnetic induction by the action of the magnetic field of the magnetic field generation means, and a heat generating member which forms a nip portion of the material to be heated by mutual pressure contact with the electromagnetic induction heating member. A heating member for heating the material to be heated at the nip portion by utilizing heat generated by the electromagnetic induction heating member, wherein the electromagnetic induction heating member is a rotating body, and the rotating body is When the endless belt has a portion where the curvature changes in one circumference, the circumference of the rotary body is L [mm], and the time required for the rotary body to make one rotation is t [sec]. , 70 ≦ L ≦ 200 and 0.5 ≦ t ≦ 3. [3]: In the heating device of [1] or [2], the moving speed of the rotating body in the nip portion is V [mm / sec].
The heating device, wherein V ≦ 300. [4] The heating device according to any one of [1] to [3], wherein the heating device has at least one heat-generating portion in the circumferential direction of the rotating body. [5]: a magnetic field generating means, an electromagnetic induction heat generating member which generates electromagnetic induction by the action of the magnetic field of the magnetic field generating means, and a heat generating member which forms a nip portion of the material to be heated by mutual pressure contact with the electromagnetic induction heat generating member. A heating member for heating the material to be heated at the nip portion by utilizing heat generated by the electromagnetic induction heating member, wherein the electromagnetic induction heating member is a rotating body, and the rotating body is An endless belt having a portion where the curvature changes in one circumference, a roller for rotating the rotary body inside the rotary body, and a circumferential length of the rotary body being L [ m
m], and the time required for the rotator to make one revolution is t [se
c], the following condition is satisfied: 125 ≦ L ≦ 175 and 0.5 ≦ t ≦ 3. [6] The heating device according to [5], wherein the heating device has at least one heat-generating portion in the circumferential direction of the rotating body. [7] The image heating apparatus according to any one of [1] to [6], wherein the material to be heated is a recording material on which an unfixed image is formed and carried, and the image heating device heats and fixes the unfixed image on the recording material. A heating device, comprising: [8]: An image forming means for forming and carrying an unfixed image on the recording material, and a fixing means for fixing the unfixed image formed and carried on the recording material, wherein the fixing means are [1] to [6] The image forming apparatus according to any one of claims 1 to 3, wherein

[9]: an image carrier as a member to be charged, charging means for charging the image carrier, exposure means for exposing the image carrier to form an electrostatic latent image, Developing means for forming a toner image by attaching toner, transfer means for transferring the toner image on the image carrier to a transfer material, and fixing means for making the toner image transferred to the transfer material a permanent fixed image An image forming apparatus comprising: the heating device according to any one of [1] to [6].

[Operation] In the heating device according to the present invention, the circumference of a rotating body as an electromagnetic induction heating member that generates electromagnetic induction by the action of the magnetic field of the magnetic field generating means is set to 200 mm or less.
By setting the time required for the rotating body to make one rotation within 3 [sec], it is possible to suppress a temperature decrease during the rotating body making one rotation. As a result, even when the heat capacity of the rotating body is small, stable fixing performance can be ensured, and the time required for reheating the rotating body can be reduced, and a quick start can be performed. In addition, useless energy consumption can be suppressed, and low power consumption can be realized.

When the rotating body is an endless belt and has a portion where the curvature changes in one circumference, the circumference L [mm] of the rotating body is set to 70 ≦ L ≦ 200, and the rotating body makes one rotation. Time t [sec] is 0.5 ≦ t
By setting ≦ 3, it is possible to suppress a temperature decrease during one rotation of the rotating body, and in particular, it is possible to suppress a curvature change more than necessary in a curvature changing portion of the rotating body,
Good fixing performance can be ensured, and the cause of deterioration in durability of the rotating body can be eliminated. As a result, even when the heat capacity of the rotating body is small, stable fixing performance can be ensured, and the time required for reheating the rotating body can be reduced, and a quick start can be performed. In addition, useless energy consumption can be suppressed, and low power consumption can be realized.

In the case where the rotating body is an endless belt and has a portion where the curvature changes in one circumference, and a roller for rotating the rotating body is provided inside the rotating body, Of the circumference L [mm] of 125 ≦ L ≦ 17
5, and the time t [s] required for the rotating body to make one rotation.
By setting ec] to 0.5 ≦ t ≦ 3, it is possible to suppress the temperature drop during one rotation of the rotating body, and to define the amount of curvature change at the roller position of the rotating body by the roller. In addition, it is possible to suppress a change in curvature more than necessary in a portion where the curvature of the rotating body changes, and it is possible to secure good fixing performance and to wipe out a cause of deterioration in durability of the rotating body. Thereby, even when the heat capacity of the rotating body is small, stable fixing performance can be ensured.
The time required for reheating the rotating body can be shortened, quick start can be performed, and wasteful energy consumption can be suppressed, and low power consumption can be realized.

The image forming apparatus according to the present invention is provided with the fixing device for fixing the unfixed image formed on the recording material and carrying the heating device. Therefore, the heat capacity of the rotating member constituting the fixing device is reduced. Even when the size is small, stable fixing performance can be ensured, and the time required for reheating the rotating body can be shortened, enabling a quick start, and suppressing wasteful energy consumption. And low power consumption can be realized.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment (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 embodiment is a four-color image printer using an electrophotographic process.

Reference numeral 101 denotes an electrophotographic photosensitive drum (image carrier) made of an organic photosensitive member or an amorphous silicon photosensitive member, which 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 its rotation.

Next, the charged surface is subjected to a scanning exposure process of target image information by a laser beam 103 output from a laser optical box (laser scanner) 110 as an exposure device.

The laser optical box 110 is modulated (ON / OFF) according 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
The surface of the rotating photosensitive drum 101 is scanned and exposed to form an electrostatic latent image corresponding to the target image information.

A mirror 109 deflects the output laser light 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 (transfer device) 105.

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 second color separation component image (for example, the magenta component image, the magenta developing device 104M is operated) of the full-color image whose process cycle of charging, scanning exposure, development, primary transfer, and cleaning as described above is intended, and third (For example, the cyan component image and the cyan developing unit 104C are activated) and the fourth color separated component image (for example, the black component image and the black developing unit 104BK are activated). On the surface of the transfer drum 105, four color 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, and a color toner image corresponding to a target full-color image is synthesized and formed. You.

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 an arrow, and a bias potential is applied to the metal drum of the intermediate transfer drum 105 so that a toner image on the photosensitive drum 101 side is applied to the surface of the intermediate transfer drum 105 by a potential difference from the photosensitive drum 101. Transfer to

The color toner image synthesized and formed on the surface of the rotary intermediate transfer drum 105 is transferred to a secondary transfer portion T2 which is a contact nip between the rotary intermediate transfer drum 105 and a transfer roller (transfer device) 106. , The secondary transfer portion T
2 is transferred onto the surface of the recording material P as a heated material fed at a predetermined timing from a paper feeding unit (not shown). The transfer roller 106 supplies a charge having a polarity opposite to that of the toner from the rear surface of the recording material P, thereby sequentially transferring the combined color toner images collectively 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 separated from the surface of the intermediate transfer drum 105, introduced into the image heating device (fixing device) 100, and subjected to the heat fixing process of the unfixed toner image. The sheet is discharged to a discharge tray (not shown) outside the apparatus as a color image formed product. The image heating 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 residues such as untransferred toner and paper dust. The cleaner 108 is normally kept in a non-contact state with the intermediate transfer drum 105, and is kept in contact with the intermediate transfer drum 105 in the process of performing the secondary transfer of the color toner image from the intermediate transfer drum 105 to the recording material P. Is held.

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 image forming apparatus of this 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, which has exited the image heating device 100, is turned upside down via a recirculation transport mechanism (not shown) and returns to the secondary transfer portion T2 again. The two-sided image is transferred to receive the toner image transfer on the two surfaces, and is again introduced into the image heating device 100 to undergo the fixing process of the toner image on the two surfaces to output a two-sided image print.

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

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

(2) Image Heating Apparatus (Fixing Apparatus) 100 A) Overall Schematic Configuration of Image Heating Apparatus 100 FIG. 2 is a schematic cross-sectional side view of a main part of the image heating apparatus of this embodiment, and FIG. FIG. 4 is a longitudinal sectional front view of a main part of the image heating apparatus.

The image heating apparatus 100 of this embodiment is, similarly to the image heating apparatus of FIG. 14, an apparatus of a pressure roller driving system using a cylindrical electromagnetic induction heating film and an electromagnetic induction heating system. Note that the same reference numerals are given to the same constituent members and portions as those of the image heating apparatus in FIG. 14, and the description will not be repeated.

17a, 17b and 17c are magnetic cores having a high magnetic permeability, and are preferably made of a material used for a transformer core such as ferrite or permalloy.
It is preferable to use ferrite with a small loss even at 0 kHz or more. The magnetic cores 17a, 17b, and 17c are formed so as to have a substantially T-shaped cross section and are disposed in a film guide member 16a having a substantially semicircular trough-shaped cross section.
The magnetic cores 17a, 17b, and 17c are an exciting coil
8 together form a magnetic field generating means.

Reference numeral 16b denotes an upper film guide member having a trough-like shape with a substantially semi-circular cross section and disposed above the film guide member 16a. The film guide member 16a and the upper film guide member 16b are substantially cylindrical members. Is configured. The upper film guide member 16b can be omitted.

Outside the assembly of the film guide member 16a and the upper film guide member 16b, there is a rotating body as an electromagnetic induction heating member, that is, a fixing film 10 which is a cylindrical electromagnetic induction heating film as an endless belt. Is loosely fitted.

Reference numeral 22 denotes a film guide member 16a on which the magnetic cores 17a, 17b, and 17c and the exciting coil 18 are disposed.
Is a horizontally-long pressurizing rigid stay disposed in contact with the upper surface flat portion.

Reference numeral 19 denotes an insulating member for insulating the magnetic cores 17a, 17b, and 17c from the rigid stay 22 for pressing.

23a and 23b are film guide members 16
A flange member for regulating and holding the end of the fixing film 10 which is fitted to the left and right ends of the assembly of the upper and lower film guide members 16a and fixed in position.

The pressure roller 30 serving as a pressure member is made of a heat-resistant and elastic material such as silicone rubber, fluorine rubber, or fluororesin, which is formed by concentrically forming a roller around the core 30a. And a material layer 30b,
Both ends of the metal core 30a are rotatably supported by bearings between a metal plate (not shown) of the apparatus.

Pressing springs 25a and 25b are respectively contracted between both ends of the pressing rigid stay 22 and spring receiving members 29a and 29b on the apparatus chassis side, so that a pressing force is applied to the pressing rigid stay 22. ing. As a result, the lower surface of the film guide member 16a and the upper surface of the pressure roller 30 are pressed against each other with the fixing film 10 interposed therebetween, thereby forming a fixing nip portion N having a predetermined width.

The pressing roller 30 is driven to rotate in the counterclockwise direction shown 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,
The fixing film 10 has a peripheral speed substantially corresponding to the rotational peripheral speed of the pressure roller 30 in the clockwise direction as indicated by the arrow while the inner surface of the fixing film 10 slides in the fixing nip portion N in close contact with the lower surface of the film guide member 16a. The outer periphery of the member 16a and the upper film guide member 16b is rotated.

In this case, in order to reduce the mutual sliding friction force between the lower surface of the film guide member 16a and the inner surface of the fixing film 10 in the fixing nip N, the fixing nip N
The lower surface of the film guide member 16a and the fixing film 10
A lubricant such as heat-resistant grease can be interposed between the inner surface of the film guide member and the lower surface of the film guide member 16a.

The film guide member 16a presses the fixing nip N, supports the magnetic cores 17a, 17b, 17c and the exciting coil 18, and controls the upper film guide member 1
The fixing film 10 supports the fixing film 10 in cooperation with the fixing film 6b, and serves to improve the conveyance stability when the fixing film 10 rotates.

Reference numeral 16e (see FIG. 5) denotes a plurality of lower film guide circumferential ribs formed on the outer peripheral side surface of the film guide member 16a at intervals along the length of the film guide member 16a. is there. This convex rib portion 16
e is the side of the film guide member 16a and the fixing film 1
0 to reduce the contact sliding resistance with the inner surface of the fixing film 1
It acts to reduce the zero rotational load. Such a convex rib portion 16e can be formed and provided on the upper film guide member 16b in a similar shape.

The excitation coil 18 in the film guide member 16a is connected to an excitation circuit 27 (see FIG. 5) at power supply portions 18a and 18b. The excitation circuit 27 can generate a high frequency of 20 kHz to 500 kHz by a switching power supply.

The exciting coil 18 in the film guide member 16a generates an alternating magnetic flux by an alternating current (high-frequency current) supplied from the exciting circuit 27.

FIG. 6 schematically shows a state of generation of an alternating magnetic flux near the fixing nip portion N. 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 concentrated and distributed between the magnetic cores 17a and 17b, between the magnetic cores 17a and 17c, that is, before and after the fixing nip N. First, an eddy current is generated in the electromagnetic induction heating layer (hereinafter, referred to as a heating layer) 1 of the fixing film 10 mainly before and after the fixing nip portion N. This eddy current generates Joule heat (eddy current loss) in the heating layer 1 due to the specific resistance of the heating layer 1. The heat value Q here is determined by the density of the magnetic flux passing through the heat generating layer 1 and shows a distribution as shown in the graph of FIG. In the graph of FIG. 6, the horizontal axis represents the fixing nip center O, and the position of the fixing film 10 is represented by an angle θ from the fixing nip center O. The vertical axis represents the heat value Q in the heat generating layer 1 of the fixing film 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 (heat generation portion) where a heat generation amount necessary for fixing is obtained.

The temperature of the fixing nip N is controlled such that a predetermined temperature is maintained by controlling the current supply to the exciting coil 18 by a temperature control system including a temperature detecting means (not shown). Reference numeral 26 denotes a temperature sensor such as a thermistor for detecting the temperature of the pressure roller 30. In this example, the temperature sensor 26 controls the temperature of the fixing nip N in consideration of the temperature information of the pressure roller 30. I have.

Thus, the pressure roller 30 is driven to rotate,
Along with this, the cylindrical fixing film 10 rotates around the film guide member 16a and the upper film guide member 16b, and the excitation circuit 27 causes the film guide member 16a to rotate.
By supplying power to the exciting coil 18 in the inside, the electromagnetic induction heat of the fixing film 10 is generated as described above, and the fixing nip portion N rises to a predetermined temperature and is adjusted in temperature. In such a temperature-controlled state, the image forming means (image forming means) IM shown in FIG.
The recording material P, on which the unfixed toner image t is formed, is introduced between the fixing film 10 and the pressure roller 30 in the fixing nip N, with the image surface facing upward, that is, facing the fixing film surface. In the fixing nip portion N, the image surface is in close contact with the outer surface of the fixing film 10, and the fixing nip portion N is conveyed together with the fixing film 10. In the process in which the recording material P is nipped and conveyed through the fixing nip portion N together with the fixing film 10, the unfixed toner image t on the recording material P is heated by electromagnetic induction heat of the fixing film 10, and the recording is performed. Heated and fixed on the surface of the material. When the recording material P passes through the fixing nip portion N, it is separated from the outer surface of the rotary fixing film 10 and discharged and conveyed. After passing through the fixing nip N, the heat-fixed toner image on the recording material P is cooled and becomes a permanent fixed image.

The flange members 23a and 23b receive the end of the fixing film 10 when the fixing film 10 rotates, and play a role in regulating the shift of the fixing film 10 along the length of the film guide member. This flange member 23a.2
3b may be configured to rotate following the fixing film 10.

In this embodiment, since a toner containing a low softening substance is used in the toner t, the image heating apparatus 100 is not provided with an oil coating mechanism for preventing offset. When used, 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.

B) Excitation Coil 18 As the excitation coil 18, a bundle (bundled wire) of a plurality of copper thin wires, each of which is insulated and coated, is used as a conductor (electric wire) constituting a coil (wire loop). This is wound around the magnetic core 17a a plurality of times to form an exciting coil. In this example, the exciting coil 18 is formed by winding 12 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 film 10. In this example, coating with polyimide is used, and the heat-resistant temperature is 220 ° C.

Here, the density may be improved by applying pressure from the outside of the exciting coil 18.

As shown in FIG. 2, the shape of the exciting coil 18 conforms to the curved surface of the electromagnetic induction heating layer 1 of the fixing film 10. In this embodiment, the distance between the electromagnetic induction heating layer 1 of the fixing film 10 and the exciting coil 18 is set to be approximately 2 mm.

As the material of the film 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, a phenol resin, a fluorine resin, a polyimide resin, a polyamide resin, a polyamideimide resin, a PEEK resin, a PES resin, a PPS resin, a PFA resin, a PTFE resin, a FEP resin, an LCP resin, or the like may be selected.

The closer the distance between the magnetic cores 17a, 17b, 17c and the exciting coil 18 and the heat generating layer 1 of the fixing film 10 is to the extent possible, the higher the efficiency of absorbing magnetic flux. If it exceeds, this efficiency is remarkably reduced, so it is preferable to keep the efficiency within 5 mm. Also, 5mm
Within this range, the distance between the heating layer 1 of the fixing film 10 and the exciting coil 18 does not need to be constant.

The film guide member 16 of the exciting coil 18
With respect to the lead wire from a, that is, the power feeding portions 18a and 18b, the outside of the bundled wire is coated with insulation for the portion outside the film guide member 16a.

C) Fixing Film 10 FIG. 7 is a schematic diagram of the layer structure of the fixing film 10 in this embodiment. The fixing film 10 of this embodiment includes a heating layer 1 made of a metal film or the like serving as a base layer of an electromagnetic induction heating fixing film, an elastic layer 2 laminated on its outer surface, and a release layer 3 laminated on its outer surface. It has a composite structure. A primer layer (not shown) may be provided between each layer for adhesion between the 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 film 10, the heat generating layer 1 is on the inner side, and the release layer 3 is on the outer side. As previously mentioned,
When the 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 is applied to the elastic layer 2
The fixing film 10 is heated via the release layer 3, and the recording material as the material to be passed through the fixing nip N is heated to heat and fix the toner image.

(A) Heating Layer 1 The heating layer 1 may be made of a nonmagnetic metal, but is preferably made of a ferromagnetic metal such as nickel, iron, ferromagnetic SUS, or a 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.
Is expressed as σ = 503 × (ρ / fμ) ^1/2 with the specific resistance ρ [Ωm].

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. (See FIG. 9).

The thickness of the heat generating layer 1 is preferably 1 to 100 μm.
m is good. 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 heating layer 1 is 1 to 1
00 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 500 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. Areas with a large amount of heat transfer have high gloss,
The glossiness is low in portions where the amount of heat transfer is small. 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 50.
0 μm is preferred.

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 not more than 60 ° (JIS-A), and more preferably 45 ° (JIS-A).
IS-A) The following is preferred.

The thermal conductivity λ of the elastic layer 2 is from 6 × 10 ⁻⁴ to 2 × 10 ⁻³ [cal / cm · sec · de].
g. ] Is good.

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

The thermal conductivity λ is 2 × 10 ⁻³ [cal / cm ·
sec deg. ], The hardness becomes too high and 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. If the thickness of the release layer 3 exceeds 100 μm, a problem that heat conduction is deteriorated occurs. In particular, in the case of a resin-based release layer, the hardness becomes too high, and the effect of the elastic layer 2 is lost.

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

As the heat insulating layer 4, a fluororesin, a polyimide resin, a polyamide resin, a 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 17a
The distance of the heating layer 1 from the coils 17b and 17c and the exciting coil 18 increases, and the magnetic flux is not sufficiently absorbed by the heating layer 1.

The heat insulating layer 4 can insulate heat generated in the heat generating layer 1 so as not to go to the inside of the fixing film 10, so that the efficiency of heat supply to the recording material P side as compared with the case without the heat insulating layer 4. Will be better. Therefore, power consumption can be suppressed.

D) Measures to Improve Fixability, Measures for Quick Start, and Measures for Low Power Consumption In this example, the circumference of the fixing film 10 that generates heat by electromagnetic induction and the time required for the fixing film 10 to make one rotation are as follows. By setting to, quick start is realized and power consumption is reduced while stable fixing property is secured.

The heat generating layer 1 of the fixing film 10 has a small heat capacity because it is thin, and has good heat dissipation because it has a good thermal conductivity due to metal. Therefore, when the circumferential length L of the fixing film 10 exceeds 200 [mm], the fixing film 10
The temperature drop during one revolution is too large to perform a quick start. In addition, power consumption increases due to an increase in the heating area accompanying an increase in the circumference. For this reason, the circumferential length L of the fixing film 10 must be 200 [mm] or less.

Since the width of the fixing nip N portion needs to be 7 [mm] or more in order to ensure good fixing property, the flat portion on the lower surface of the film guide 16a must be secured to 8 [mm] or more. The circumferential length L of the fixing film 10 is 70 [m
m], the change in curvature at both ends 10a of the fixing nip N (the upstream end and the downstream end of the fixing film 10) becomes too large, and the durability of the fixing film 10 is significantly deteriorated. For this reason, the circumference L of the fixing film 10
Must be 70 [mm] or more.

When the rotation speed (moving speed) V of the fixing film 10 exceeds 300 [mm / sec], the fixing film 10 cannot be rotated stably, and the fixing film 10 is damaged. Therefore, the fixing film 1
The process speed as the rotation speed V of 0 is 300 [m
m / sec] or less.

The time t required for the fixing film 10 to make one rotation is preferably within 3 [sec]. This is because the temperature reduction rate of the fixing film 10 is 15 to 20 [deg. / S
ec], and 45 to 60 [de] in 3 [sec].
g. ] The temperature drops. If the time t required for one rotation of the fixing film 10 is within 3 [sec], a sufficient temperature increase can be obtained when the fixing film 10 makes one rotation and returns to the heating portion (heat generating portion) again. , Quick start is possible. However, when the time exceeds 3 [sec], a sufficient rate of temperature rise cannot be obtained, and quick start cannot be performed. Therefore, the time t required for the fixing film 10 to make one rotation is preferably within 3 [sec].

The time t required for the fixing film 10 to make one rotation is preferably 0.5 [sec] or more. this is,
When the fixing film 10 is rotated at less than 0.5 [sec] per rotation, the rotation of the fixing film 10 is not stabilized, and the fixing film 10 is blurred and disturbs the toner image on the recording material at the entrance of the nip. Would. Therefore, the time t required for the fixing film 10 to make one rotation is 0.5
[Sec] or more is preferable.

The region satisfying the above is shown in the graph of FIG. In FIG. 10, the area satisfying the above is a hatched area with hatching. As is clear from this graph, the process speed was set to 300 [mm / sec.
c] or less (0 <V (≦ 300)), the peripheral length L of the fixing film 10 is 200 [mm] or less, preferably 7 mm or less.
By setting 0 ≦ L ≦ 200 [mm] and the time t required for the fixing film 10 to make one rotation within 3 [sec], preferably 0.5 ≦ t ≦ 3 [sec], quick start and low Power consumption becomes possible, and stable and good fixing properties are obtained.

Incidentally, the peripheral length L of the fixing film 10 is set to 70 ≦
When L ≦ 200 [mm] and the time t required for the fixing film 10 to make one rotation is 0.5 ≦ t ≦ 3 [sec], the lower limit value Vmin of the process speed is 70 [m].
m] / 3 [sec] = 23.33 ° and <Vmin.

As described above, in this embodiment, by satisfying the above, quick start and low power consumption can be achieved while securing stable and good fixing performance.

[Second Embodiment] In this embodiment, as shown in FIG.
And a tension roller 31, and other mechanical configurations are the same as those of the first embodiment. In addition, the same reference numerals are given to the same constituent members and portions as those in the first embodiment, and the description will not be repeated.

By providing a fixing film shift control mechanism (not shown) in the configuration as in this example, the fixing film 1
0 can be rotated stably. However, in the configuration of the present example, since the drive roller 32 and the tension roller 31 are in contact with the inner surface of the fixing film 10,
The temperature drop during one rotation of the fixing film 10 is caused by the roller 1
About 5 [deg. ]descend.

Therefore, in this example, in order to realize the quick start, the temperature drop during one rotation of the fixing film 10 must be reduced. By setting the peripheral length L of the fixing film 10 to 175 [mm] or less, the amount of temperature drop is equal to that of the first embodiment, and a quick start can be realized.

In order to stably rotate the fixing film 10, the diameter D of the drive roller 32 and the tension roller 31 is preferably D ≧ 15 [mm] or more. This is because by defining the amount of change in the curvature of the fixing film 10 at the position of the drive roller 32 and the tension roller 31, the bending change of the fixing film 10 is suppressed and the durability of the fixing film 10 is improved. Further, the contact area between the drive roller 32 and the fixing film 10 is ensured, and the fixing film 10 can be rotated without slipping.

As in this example, two rollers having a diameter D ≧ 15 [mm] are arranged in the fixing film 10 and a nip forming portion (fixing nip portion N) is provided.
Is set to 125 [mm] or more.

The time t required for the fixing film 10 to make one rotation is preferably within 3 [sec]. This is because the temperature reduction rate of the fixing film 10 is 15 to 20 [deg. / S
ec], and 45 to 60 [de] in 3 [sec].
g. ] The temperature drops. If the time t required for one rotation of the fixing film 10 is within 3 [sec], a sufficient temperature rise can be obtained when the fixing film makes one rotation and returns to the heated portion, so that quick start is possible. It is. However, when the time exceeds 3 [sec], a sufficient rate of temperature rise cannot be obtained, and quick start cannot be performed.
Therefore, the time t required for the fixing film 10 to make one rotation is preferably within 3 [sec].

The above is shown in the graph of FIG.
In FIG. 12, the area satisfying the above is a hatched area. As is clear from this graph,
By arranging the drive roller 32 and the tension roller 31 in the fixing film 10 and providing a fixing film shift control mechanism (not shown) as in the present embodiment, the rotation of the fixing film 10 compared to the first embodiment is improved. The process speed, which is the speed (moving speed) V, could be improved. actually,
When the circumferential length L of the fixing film was 175 [mm], the process speed was 350 [mm / sec], and a quick start and good fixability could be obtained.

[Other Embodiments] 1) In the above embodiment, pressurizing springs 25a and 25b are respectively contracted between both ends of the pressurizing rigid stay 22 and spring receiving members 29a and 29b on the apparatus chassis side. Thus, a pressing force is applied to the pressing rigid stay 22 to form a fixing nip portion N having a predetermined width with the fixing film 10 interposed between the lower surface of the film guide member 16a and the upper surface of the pressing roller 30. Conversely, both ends of the pressing rigid stay 22 are fixed in position, and a pushing-up force is applied to the pressing roller 30 by an urging member (a pressing spring) so that the film guide member 16 a
A fixing nip portion N having a predetermined width may be formed by sandwiching the fixing film 10 between the lower surface of the pressing roller 30 and the upper surface of the pressing roller 30, or both the pressing rigid stay 22 and the pressing roller 30 may be biased by the urging members ( The fixing nip N having a predetermined width may be formed by pressing the fixing film 10 between the lower surface of the film guide member 16a and the upper surface of the pressing roller 30 by mutually pressing each other with a pressing spring.

2) The image forming apparatus of the embodiment is a four-color image forming apparatus, but may be a monochrome or one-pulse multi-color image forming apparatus.

3) Fixing film 10 of electromagnetic induction heat generation
In the case of heat fixing such as a monochrome or one-pulse multicolor image, the elastic layer 2 may be omitted. The heat generating layer 1 may be formed by mixing a metal filler into a resin. Further, the heat generating layer may be a single layer member.

4) Magnetic field generating means (magnetic cores 17a and 17)
The arrangement of b · 17c and the exciting coil 18) is not limited to the embodiment. For example, as shown in FIG.
The same effect can be obtained even if the magnetic field generating means is disposed by being rotated about 90 ° on the upstream side of the fixing film 10.

5) The pressure member (pressure roller) 30 is not limited to a roller body, but may be another type of member such as a rotating belt type.

In order to supply thermal 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.

6) The heating device of the present invention is not limited to the image heating and fixing device which is an example of the image heating device of each embodiment, and a recording material carrying an image is heated to improve the surface properties such as gloss. It can be widely used as a device or apparatus for performing heat treatment on a material to be heated, such as an image heating device, an image heating device for temporary attachment, a heating and drying device for a material to be heated, and a heating laminating device.

7) The image forming principle and method of the image forming apparatus is not limited to the electrophotographic process, but may be any other method such as a transfer type or direct type electrostatic recording process and magnetic recording process.

[0124]

As described above, according to the present invention, by appropriately setting the circumference of the rotating body as the electromagnetic induction heating member and the time required for the rotating body to make one rotation, Even if a rotating body having a small heat capacity and good heat dissipation is used as the electromagnetic induction heat-generating member, it is possible to provide a heating apparatus and an image forming apparatus that realize quick start and low power consumption while securing stable and good fixing properties.

[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 side cross-sectional model view of a main part of a heating device (image heating device) used in the first embodiment.

FIG. 3 is a front model view of a main part of the heating device.

FIG. 4 is a longitudinal sectional front model view of a main part of the heating device.

FIG. 5 is a perspective view showing an arrangement relationship between a film guide member, an exciting coil, and a magnetic core of the heating device.

FIG. 6 is a diagram showing a relationship between a magnetic flux generated by a magnetic field generating means of the heating device and a heat generation amount of a fixing film.

FIG. 7 is a schematic diagram of a layer structure showing an example of a layer structure of a fixing film having electromagnetic induction heat generation.

FIG. 8 is a layer configuration model diagram showing another example of a layer configuration of a fixing film having an electromagnetic induction heating property.

FIG. 9 is a graph showing a relationship between a heating layer depth and an electromagnetic wave intensity.

FIG. 10 is a graph showing the relationship between the circumference of the fixing film, the process speed of the fixing film, and the time required for the fixing film to make one rotation in the heating device of the first embodiment.

FIG. 11 shows a heating device (image heating device) according to the second embodiment.
It is a cross-sectional side model figure of the principal part of FIG.

FIG. 12 is a graph showing the relationship between the circumference of the fixing film, the process speed of the fixing film, and the time required for the fixing film to make one rotation in the heating device of the second embodiment.

FIG. 13 is a schematic cross-sectional side view of a main part illustrating an example of a heating device according to another embodiment.

FIG. 14 is a schematic configuration diagram illustrating an example of a conventional heating device (image heating device) of an electromagnetic induction heating system.

[Explanation of symbols]

P Recording material (heated material) N Fixing nip portion (nip portion) H Heating area (heating portion) IM Image forming means 10 Fixing film (electromagnetic induction heating member) 10a End portion (curvature changing portion) 17a 17b / 17c Magnetic core (magnetic field generating means) 18 Excitation coil (magnetic field generating means) 30 Pressure roller (Pressing member) 31 Tension roller (roller) 32 Drive roller (roller) 100 Image heating device (fixing device or heating device) Reference Signs List 101 electrophotographic photosensitive drum (image carrier) 102 charging device (charging means) 104 developing device (developing means) 106 transfer roller (transfer means) 105 intermediate transfer drum (transfer means) 110 laser scanner (exposure means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koichi Tanigawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (9)

[Claims] 1. A magnetic field generating means, an electromagnetic induction heating member which generates electromagnetic induction by the action of a magnetic field of the magnetic field generation means, and a nip portion of a material to be heated by mutual pressure contact with the electromagnetic induction heating member. A heating member for heating a material to be heated in a nip portion by utilizing heat generated by the electromagnetic induction heating member, wherein the electromagnetic induction heating member is a rotating body, and the rotating body The heating device has a circumference of 200 [mm] or less, and a time required for the rotating body to make one rotation is within 3 [sec]. 2. A magnetic field generating means, an electromagnetic induction heating member for generating electromagnetic induction by the action of a magnetic field of the magnetic field generating means, and a nip portion of a material to be heated by mutual pressure contact with the electromagnetic induction heating member. A heating member for heating a material to be heated in a nip portion by utilizing heat generated by the electromagnetic induction heating member, wherein the electromagnetic induction heating member is a rotating body, and the rotating body Is an endless belt having a portion where the curvature changes in one circumference, the circumference of the rotating body is L [mm], and the time required for the rotating body to make one rotation is t [sec]. In this case, the heating device satisfies 70 ≦ L ≦ 200 and 0.5 ≦ t ≦ 3. 3. The heating device according to claim 1, wherein the moving speed of the rotating body in the nip is V [mm].
/ Sec], V ≦ 300. 4. The heating device according to claim 1, wherein at least one of the heating units is arranged in a circumferential direction of the rotating body.
A heating device having more than one heat generating portion. 5. A magnetic field generating means, an electromagnetic induction heating member which generates electromagnetic induction by the action of a magnetic field of the magnetic field generating means, and a nip portion of a material to be heated by mutual pressure contact with the electromagnetic induction heating member. A heating member for heating a material to be heated in a nip portion by utilizing heat generated by the electromagnetic induction heating member, wherein the electromagnetic induction heating member is a rotating body, and the rotating body Is an endless belt having a portion where the curvature changes in one circumference, a roller inside the rotary body for driving the rotary body to rotate, and a circumferential length of the rotary body is L. [Mm], and when the time required for the rotator to make one rotation is t [sec], 125 ≦ L ≦ 175 and 0.5 ≦ t ≦ 3 are satisfied. 6. The heating device according to claim 5, wherein the heating device has at least one or more heat generating portions in a circumferential direction of the rotating body. 7. The image heating apparatus according to claim 1, wherein the material to be heated is a recording material on which an unfixed image is formed and carried, and the image heating device heats and fixes the unfixed image on the recording material. A heating device comprising a heating device. 8. An image forming means for forming and carrying an unfixed image on a recording material, and a fixing means for fixing the unfixed image formed and carried on the recording material, wherein the fixing means is provided. An image forming apparatus, which is the heating apparatus according to any one of the above. 9. An image carrier as a member to be charged, charging means for charging the image carrier, exposure means for exposing the image carrier to form an electrostatic latent image, and the electrostatic latent image Developing means for forming a toner image by adhering toner to the toner, transferring means for transferring the toner image on the image carrier to a transfer material, and fixing means for making the toner image transferred to the transfer material a permanent fixed image An image forming apparatus comprising: the heating device according to claim 1.