JPH0980940A - Heating device - Google Patents

Abstract

(57) [Abstract] [Problem] Quick start-up is possible, heat energy can be efficiently transmitted to the nip to reduce power consumption, and the temperature in the nip can be accurately detected. A heating device that does not require complicated control such as multi-step temperature control is provided. A fixing film, a heating body made of aluminum nitride fixedly supported on one surface side of the fixing film, and provided on the other side of the fixing film so as to face the heating body. A heating device having a pressure member and heating and fixing the toner image is produced by passing a recording material having a toner image through a nip portion formed by pressure contact between a heating body and the pressure member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device used in an image forming apparatus or the like.

[0002]

2. Description of the Related Art For example, an image heating and fixing device of an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, etc., that is, an image forming process means such as electrophotography, electrostatic recording, magnetic recording or the like can be used to reveal the heat fixing property. Target image information that is formed and carried on the surface of a recording material (transfer material sheet, printing paper, electro-fax sheet, electrostatic recording sheet, etc.) using an image agent (toner) by indirect (transfer) method or direct method. As a heating device for heating and fixing the unfixed developer image corresponding to the above on the recording material surface, a heating roller type device has been generally used in the past.

This heating device of the hot roller type is a pressure contact nip portion between a heating roller (fixing roller) maintained at a predetermined heating temperature by a built-in heat source such as a halogen heater and an elastic pressure roller pressed against the heating roller (fixing roller). The recording material is introduced into the fixing nip portion) and nipped and conveyed to heat and fix the unfixed developer image on the surface of the recording material by the heat of the heating roller.

However, in the heating device as the image heating and fixing device of the heat roller system, the temperature of the heating roller must be constantly maintained at a high temperature so that an image can be output immediately at any time. It consumes a lot of energy, and heat is released into the machine even during standby, causing a problem of temperature rise inside the machine. Further, it takes a considerable waiting time after the power is turned on until the heating roller rises to a predetermined temperature suitable for heating the recording material as the material to be heated.

Recently, a film heating type heating device has been proposed and put into practical use (Japanese Patent Laid-Open No. 63-31318).
No. 2, JP-A-1-263679, JP-A-2-
No. 157878, JP-A-4-44075-4408
No. 3, JP-A-4-204980 to 204984).

In this heating apparatus, a material to be heated is brought into close contact with a heating body via a heat resistant film, and the heating body and the heat resistant film are moved relative to each other so that heat of the heating body is applied to the heating material via the heat resistant film. It is possible to utilize the unfixed toner image as a means for heating and fixing the unfixed toner image as a permanently fixed image on the surface of the recording material carrying the image.

Further, for example, an apparatus for heating a recording material carrying an image to modify the surface properties such as gloss, a hypothetical processing apparatus, and other means for heat-treating a sheet-shaped heating material. Can be widely used as

In such a film heating type heating device, since a heating body having a low heat capacity and a thin film which can quickly rise in temperature can be used, the temperature of the heating body rises in a short time, and the heating body is heated during standby. It is no longer necessary to carry out the energization heating of the recording material, and even if the recording material as the material to be heated is immediately passed, it is possible to sufficiently raise the temperature of the heating element to a predetermined temperature before the recording material reaches the fixing portion. It is possible to save power and shorten the wait time (quick start property), and to lower the temperature rise inside the machine such as the image forming apparatus. .

FIG. 2 is a schematic view showing a schematic structure of a conventional film heating type heating device (image heating device, image heating and fixing device). FIG. 2A shows an enlarged cross-sectional schematic view of the essential part of an example of a film heating type heating device (image heating and fixing device). FIG. 2B is a schematic partially cutaway plan view of the heating element. FIG. 2C is a schematic diagram showing details around the heating body.

This heating device is a pressure roller drive type device, and a cylindrical heat-resistant film 8 (a PFA or PTFE film on a base film such as a polyimide film) is attached to a heating member holder 7 holding a heating member 10. A film coated with a heat-resistant resin having releasability is loosely fitted outside, and a pressure roller 9 is sandwiched between the films 8 and pressed against the heating body 10 with a predetermined pressing force to form a space between the heating body 10 and the heating body 10. A fixing nip portion N is formed with the film 8 interposed therebetween.

The pressure roller 9 is rotationally driven by the driving means M in the counterclockwise direction indicated by the arrow. The pressure roller 9
The rotational force acts on the film 8 due to the frictional force between the roller 9 and the outer surface of the film 8 due to the rotational drive of the cylindrical film 8 and the cylindrical film 8 holds the heating body 10. Direction (width direction of the heating element 10).

When the film 8 is rotated by the rotation of the pressure roller 9 and the temperature of the heating body 10 is raised to a predetermined value by energizing the heating body 10, the film 8 in the fixing nip portion N and the pressure roller 9 are A recording material P carrying an unfixed toner image T which is a sheet-shaped material to be heated between
Of the heating element 10 is introduced into the recording material 8 through the fixing nip portion N together with the film, and the heat of the heating element 10 is applied to the recording material via the film 8 to form the unfixed toner image T. The surface of the recording material P is heat-fixed. The recording material P passing through the fixing nip portion N is separated from the surface of the film 8 by curvature and is conveyed.

As shown in FIG. 2B, the heating element 10 is a heater substrate (heating element base material) 2, a resistance heating element (conduction heating element) pattern 3 formed on one side of the heater substrate 2, The conductor pattern 4, the conductive pattern 4a, the two power supply electrode patterns 5 and 6, the resistance heating element pattern 3, and the surface protection layer 7 covering the conductor pattern 4 portion are included. The heater substrate 2 is horizontally long and thin with a longitudinal direction being a direction orthogonal to the transporting / moving direction A of a heat resistant film 8 and a recording material P as a material to be heated, which will be described later.
It is a ceramic substrate having heat resistance, electric insulation and low heat capacity, which is made of alumina having a size of 40 mm, a width of 10 mm and a thickness of 1 mm.

The resistance heating element pattern 3 is made of, for example, an electrical resistance material paste (resistive paste) such as silver palladium (Ag / Pb) or Ta ₂ N having a thickness of 10 μm and widths of 1 to 3.
It is formed by applying a thin strip of mm along the longitudinal direction of the surface of the ceramic substrate by screen printing or the like and firing.

The conductor pattern 4 is formed substantially in parallel with the resistance heating element pattern 3 in the form of a strip along the length of the ceramic substrate surface.

The two power supply electrode patterns 5 and 6 are provided side by side on the surface on one end side of the ceramic base material 2.

Then, one end side of the resistance heating element pattern 3 is electrically connected to one of the two feeding electrode patterns 5 and 6 through the conductive pattern 4a. One end of the conductor pattern 4 on the same side is electrically connected to the other power supply electrode pattern 6. The other ends of the resistance heating element pattern 3 and the conductor pattern 4 are electrically connected to each other.

The conductor pattern 4 and the conductive pattern 4 described above.
a, the two feeding electrode patterns 5 and 6 are formed by pattern-coating a conductive material paste such as Ag on the surface of the ceramic base material 2 by screen printing or the like and firing.

The resistance heating element pattern 3 and the conductor pattern 4, which are substantially parallel to each other, serve as an energization path in the longitudinal direction of the heating element between the two feeding electrode patterns 5 and 6 provided on one end side in the longitudinal direction of the ceramic base material 2. It forms a return path.

This heating element 10 is replaced with a resistance heating element pattern 3
The surface on which is formed is exposed downward, and is held and fixed by a heating body holder (stay) 11 having rigidity and heat insulation.

This heating element 10 has a power supply electrode pattern 5
6, the resistance heating element pattern 3 heats up over the entire length by supplying power from a power supply circuit (not shown), and the temperature rise is detected by the temperature detecting element (thermistor) 20, and the detected temperature is not shown. The current is fed back to the temperature control circuit and the energization to the resistance heating element pattern 3 is controlled so that the temperature of the heating element 10 is maintained at a predetermined temperature.

Reference numeral 8 is a heat-resistant film of polyimide or the like having a thickness of, for example, about 40 μm to 100 μm, and 9 is a pressurizing member for pressing the film 8 against the surface protective layer 7 which is the film sliding surface of the heating body 10. It is a pressure roller.

The film 8 is pressed against the heating body 10 by the pressure roller 9, and is driven by a driving means (not shown) or by a rotational driving force of the pressure roller 9 using the pressure roller 9 as a driving means in the direction of arrow A. Heating element 10 at a predetermined speed
It moves while contacting and sliding on the surface (surface protective layer 7 surface).

By energizing the resistance heating element pattern 3, the heating element 10 is heated to a predetermined temperature, and the film 8 is slid on the heating element 10.
An image as a material to be heated should be fixed between the pressure roller 9 and the heat-resistant film 8 in the fixing nip portion (pressure contact nip portion) N between the heating body 10 and the pressure roller 9 formed by sandwiching The recording material P is introduced, and the fixing nip portion N is nipped and conveyed together with the heat-resistant film 8, so that the heating body 10 is heated.
Is applied to the recording material P via the heat resistant film 8 to heat and fix the unfixed visible image (toner image) T on the recording material P on the recording material P surface. The recording material P passing through the fixing nip portion N is separated from the surface of the film 8 and conveyed.

In FIG. 2 (c), the heating element 10 is formed by laminating a paste material such as silver palladium on the alumina base material 2 by screen printing or the like, and further firing the heating material 3 and the conductor pattern. 4 is formed. In order to detect the temperature of the heating element 10 and control the temperature,
Conventionally, the thermistor 20 is attached to the back surface or the like to provide the heating element 1.
The temperature of 0 was detected and the electric power applied to the resistance heating element of the heating element was controlled to control the temperature to a predetermined value. The thermistor attached to the heating body is conventionally a chip type thermistor, and the chip thermistor 20 is made by laminating the thermistor material 14 and the electrode 13 on the alumina base material 2. Such a chip thermistor 20 is bonded to the electrode 12 provided on the back surface of the heating body with a heat-resistant conductive adhesive 15.
Reference numeral 16 is a protective glass.

In order to fix the toner on the recording material, heat energy necessary for fixing the toner on the recording material may be applied while the recording material passes through the nip of the heating device. The temperature should be kept constant.

[0027]

However, in the conventional heating device, the thermistor is arranged on the heating member opposite to the recording material sheet passing surface (nip forming surface), so that the toner is fixed on the recording material. It becomes difficult to accurately detect the required temperature in the heating device nip. Therefore, complicated control such as multi-step temperature control of the heating device is required.

Therefore, the present applicants are also investigating a heating device having a structure in which the resistance heating element forming surface of the heating element and the thermistor disposing surface are reversed from the conventional one so that the temperature in the nip can be detected. A heating device having such a configuration is shown in FIG. FIG.
FIG. 4A is a schematic cross-sectional view showing the overall configuration of the apparatus, and FIG. 4B is a schematic view showing details around the heating body.

The apparatus shown in FIG. 4 is different from the apparatus shown in FIG. 2 in that the thermistor 20, which is a temperature detecting element, is arranged on the heating body 10 on the surface opposite to the resistance heating element pattern 3. The thermistor may be in the form of chips as described above, but in order to place it in the nip, alloys such as cobalt, manganese, nickel, ruthenium, oxides, particles of ceramics such as platinum or barium titanate are used as a glass paste material. It is also possible to use a thin layer type in which a mixture of the above and the above is screen-printed on the heating body 10. A protective layer (glass) 7 is provided on the thermistor arrangement surface to form a nip forming surface.

This heating element 10 has a resistance heating element pattern 3
It is held and fixedly mounted on a heating body holder (stay) 11 having rigidity and heat insulation with the surface on which is formed facing upward. An empty wall is provided for heat insulation on the surface of the heating element holder 11 on which the resistance heating element pattern 3 is located.

With the structure shown in FIG. 4, since the thermistor can be arranged on the recording material sheet passing surface (nip forming surface), the temperature in the nip can be accurately detected, and complicated multi-step temperature control and the like are required. There is no need to perform any kind of control.

However, in the heating device having the structure shown in FIG. 4, since the resistance heating element is formed on the surface of the heating element opposite to the recording material sheet passing surface (nip forming surface), the thermal conductivity of the base material of the heating element is increased. Will greatly affect the performance of the heating device such as quick start and low power consumption. If the base material of the heating element is alumina as in the prior art, it is not possible to completely solve the problem that the heating device starts up slowly and the power consumption increases.

Therefore, according to the present invention, quick start-up is possible, heat energy can be efficiently transmitted to the nip to reduce power consumption, and the temperature in the nip can be accurately detected. It is an object of the present invention to provide a heating device that does not require complicated control such as multi-step temperature control.

[0034]

The present invention is directed to a fixing film, a heating body fixedly supported on one surface side of the fixing film, and a heating body arranged on the other surface side of the fixing film to face the heating body. A heating device that heats and fixes the toner image by passing a recording material having a toner image through a nip portion formed by the pressure contact between the heating body and the pressing member. Provided is a heating device in which a heating body is made of aluminum nitride.

In the above heating device of the present invention, it is preferable to dispose a temperature detecting element for detecting the temperature of the heating element on the side of the nip formed by the pressure contact between the heating element and the pressing member. The resistance heating element can be arranged on the surface opposite to the nip portion side formed by the pressure contact between the heating element and the pressure member.

[0036]

1 is a schematic diagram showing a schematic configuration of a heating device of the present invention.

In FIG. 1, a heating member holder 11 holding a heating member 10 has a cylindrical heat-resistant film 8 (a base material film such as polyimide is coated with a releasable heat-resistant resin such as PFA or PTFE). A heating member 10 by loosely fitting a film) and sandwiching the film 8 with a pressure roller 9.
The fixing nip portion N is formed by sandwiching the film 8 with the heating body 10 by pressing it with a predetermined pressing force.

The pressure roller 9 is rotationally driven by the driving means M in the counterclockwise direction indicated by the arrow. The pressure roller 9
The rotational force acts on the film 8 due to the frictional force between the roller 9 and the outer surface of the film 8 due to the rotational drive of the cylindrical film 8 and the cylindrical film 8 holds the heating body 10. Direction (width direction of the heating element 10).

When the film 8 is rotated by the rotation of the pressure roller 9 and the temperature of the heating body 10 is raised by energizing the heating body 10, the film 8 and the pressure roller 9 in the fixing nip portion N are separated from each other. A recording material P carrying an unfixed toner image T which is a sheet-shaped material to be heated between
Of the heating element 10 is introduced into the recording material 8 through the fixing nip portion N together with the film, and the heat of the heating element 10 is applied to the recording material via the film 8 to form the unfixed toner image T. The surface of the recording material P is heat-fixed. The recording material P passing through the fixing nip portion N is separated from the surface of the film 8 by curvature and is conveyed.

As shown in FIG. 2B, the heating element 10 includes a heater substrate (heating element base material) 2 and the heater substrate 2
The resistance heating element (energization heating element) pattern 3, the conductor pattern 4, the conductive pattern 4a, the two feeding electrode patterns 5 and 6, the resistance heating element pattern 3 and the conductor pattern 4 portion formed on one side of The surface protection layer 7 and the like are used.

The heater substrate 2 includes a heat resistant film 8 which will be described later and a conveying / moving direction A of a recording material P as a material to be heated.
It is horizontally long and thin with the direction perpendicular to
For example, length 240mm, width 10mm and thickness 1mm
Is a ceramic base material of aluminum nitride, which has heat resistance, electrical insulation and low heat capacity.

The resistance heating element pattern 3 is made of, for example, an electric resistance material paste (resistive paste) such as silver palladium (Ag / Pb) or Ta ₂ N having a thickness of 10 μm and widths of 1 to 3.
It is formed by applying a thin strip of mm along the longitudinal direction of the surface of the ceramic substrate by screen printing or the like and firing.

The conductor pattern 4 is formed in a strip shape along the longitudinal direction of the ceramic substrate substantially in parallel with the resistance heating element pattern 3.

The two feeding electrode patterns 5 and 6 are provided side by side on the surface of the ceramic substrate 2 on one end side.

The one end of the resistance heating element pattern 3 is electrically connected to one of the two feeding electrode patterns 5 and 6 through the conductive pattern 4a. One end of the conductor pattern 4 on the same side is electrically connected to the other power supply electrode pattern 6. The other ends of the resistance heating element pattern 3 and the conductor pattern 4 are electrically connected to each other.

The conductor pattern 4 and the conductive pattern 4 described above.
a, the two feeding electrode patterns 5 and 6 are formed by pattern-coating a conductive material paste such as Ag on the surface of the ceramic base material 2 by screen printing or the like and firing.

The resistance heating element pattern 3 and the conductor pattern 4 which are substantially parallel to each other serve as an energization path in the longitudinal direction of the heating element between the two power supply electrode patterns 5 and 6 provided on one end side in the longitudinal direction of the ceramic base material 2. It forms a return path.

This heating element 10 is replaced with the resistance heating element pattern 3
The surface on which is formed is exposed downward, and is held and fixed by a heating body holder (stay) 11 having rigidity and heat insulation.

This heating element 10 is composed of the feeding electrode pattern 5
6, the resistance heating element pattern 3 heats up over the entire length by supplying power from a power supply circuit (not shown), and the temperature rise is detected by the temperature detecting element (thermistor) 20, and the detected temperature is not shown. The current is fed back to the temperature control circuit and the energization to the resistance heating element pattern 3 is controlled so that the temperature of the heating element 10 is maintained at a predetermined temperature.

Reference numeral 8 is a heat-resistant film of polyimide or the like having a thickness of, for example, about 40 μm to 100 μm, and 9 is a pressing member for pressing the film 8 against the surface protective layer 7 which is the film sliding surface of the heating body 10. It is a pressure roller.

The film 8 is pressed against the heating body 10 by the pressure roller 9, and is driven by a driving means (not shown) or by the rotational driving force of the pressure roller 9 using the pressure roller 9 as a driving means in the direction of arrow A. Heating element 10 at a predetermined speed
It moves while contacting and sliding on the surface (surface protective layer 7 surface).

By energizing the resistance heating element pattern 3, the heating element 10 is heated to a predetermined temperature and the film 8 is slid on the heating element 10.
An image as a material to be heated should be fixed between the pressure roller 9 and the heat-resistant film 8 in the fixing nip portion (pressure contact nip portion) N between the heating body 10 and the pressure roller 9 formed by sandwiching The recording material P is introduced, and the fixing nip portion N is nipped and conveyed together with the heat-resistant film 8, so that the heating body 10 is heated.
Is applied to the recording material P via the heat resistant film 8 to heat and fix the unfixed visible image (toner image) T on the recording material P on the recording material P surface. The recording material P passing through the fixing nip portion N is separated from the surface of the film 8 and conveyed.

In the apparatus of FIG. 1, the thermistor 20, which is a temperature detecting element, has the heating element 1 on the surface opposite to the resistance heating element pattern 3.
0. The thermistor may be in the form of chips as described above, but in order to place it in the nip, alloys such as cobalt, manganese, nickel, ruthenium, oxides, particles of ceramics such as platinum or barium titanate are used as a glass paste material. It is also possible to use a thin layer type in which a mixture of the above and the above is screen-printed on the heating body 10. A protective layer (glass) 7 is provided on the thermistor arrangement surface to form a nip forming surface.

This heating element 10 has a resistance heating element pattern 3
It is held and fixedly mounted on the heating element holder 11 having rigidity and heat insulation with the surface on which is formed facing upward. Also,
An empty wall is provided for heat insulation on the surface of the heating element holder 11 on which the resistance heating element pattern 3 is located.

With the structure shown in FIG. 1, since the thermistor can be arranged on the recording material sheet passing surface (nip forming surface), the temperature inside the nip can be accurately detected, and complicated multi-step temperature control or the like is required. There is no need to perform any kind of control.

In the heating device of the present invention, as described above, the heating base material 2 is made of aluminum nitride (Al) having a high thermal conductivity.
N) is used. As a result, in the heating device of the present invention, the heat conductivity of the base material is higher than that of the conventional base material formed of alumina, and the heat generated on the surface opposite to the nip formation surface of the heating element is generated. The heat conduction from the body to the nip forming surface where the thermistor is arranged is better than the conventional one. As a result, the heating device starts up faster and quick start is possible. Further, since the base material of the heating body has a high thermal conductivity, the heat energy can be efficiently transmitted into the nip, and the power consumption can be reduced.

[0057]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 A heating device of the present invention having the structure shown in FIG. 1 and having the heating body substrate 2 made of aluminum nitride was manufactured. In the apparatus, the aluminum nitride layer of the heating body substrate 2 has a length of 240 mm, a width of 10 mm and a thickness of 1 m.
The resistance heating element pattern 3 is formed by applying silver-palladium paste in a strip shape having a thickness of 10 μm and a width of 1 to 3 mm along the longitudinal direction of the ceramic substrate surface by screen printing and firing; Conductive pattern 4a,
The two power feeding electrode patterns 5 and 6 are formed by screen-printing an Ag paste on the surface of the ceramic base material 2 by screen printing and firing; a thermistor 20 is cobalt;
Alloys such as manganese, nickel and ruthenium, oxides, particles of ceramics such as platinum or barium titanate were mixed with a glass paste material and screen-printed on the heating element 10 to obtain a thin layer type.

When the temperature in the nip when the toner was fixed on the recording material was measured with this apparatus, it was about 130 ° C. With the heating device of this configuration,
If the temperature is controlled by the temperature detected by the thermistor so as to keep it at 0 ° C, it will be 1
A constant temperature control of 30 ° C was possible. At this time, about 250 W of input was required for the heating device to start up in 10 seconds from the first state in the morning to the fixing possible state. This is because the thermal conductivity (180 to 220 W / mK) of aluminum nitride (AlN) used as the base material of the heating body is 10 times higher than the thermal conductivity (20 W / mK) of alumina used in the conventional apparatus. It is considered that this is because the heat energy of the resistance heating element can be efficiently transmitted to the inside of the nip because it is near high.

Therefore, in the apparatus shown in this embodiment, the temperature in the nip can be accurately detected, complicated control such as multi-step temperature control need not be performed, and low power consumption and quick start-up can be realized. be able to.

(Comparative Example 1) A heating device having a structure as shown in FIG. 2 was produced. It should be noted that the heating body substrate is alumina, and the thermistor 20 is Fe ₃ O ₄ , MgCr ₂ O ₄ , MgAl ₂ O ₄ , N.
Other than the chip thermistor made of a solid solution of a metal oxide such as iO, Mn ₂ O ₃ , Co ₂ O ₃ or the like, the dimensions of the heating body substrate 2, the formation of the resistance heating element pattern 3, and the conductor pattern 4 and the conductive pattern 4a. The formation of the two power supply electrode patterns 5 and 6 was the same as in the first embodiment.

With this apparatus, the temperature in the nip when the toner was fixed on the recording material was measured and found to be about 130.degree. With the heating device of this configuration,
If temperature control is performed at the temperature detected by the thermistor so as to keep it at 0 ° C, multi-step temperature control from 190 ° C to 150 ° C is required for continuous paper feeding started from the first state in the morning, as shown in Fig. 3. was. This is because the thermistor is placed on the heating body opposite to the recording material sheet passing surface (nip forming surface), so the temperature inside the nip due to the temperature of the pressure roller from the first state in the morning and the temperature change during sheet passing. This is because it cannot be detected accurately. At this time, it took 10 seconds with an input of about 300 W to start up the heating device from the first state in the morning to the fixing possible state.

(Comparative Example 2) Next, a heating device having the structure shown in FIG. 4 was produced. In this apparatus, except that the heating body base material 2 is alumina, the dimensions of the heating body base material 2, the formation of the resistance heating element pattern 3, the conductor pattern 4, the conductive pattern 4a, and the two power supply electrode patterns 5 and 6 are used. Formation of the
The formation of the thermistor 20 was the same as in the first embodiment.

The heating device measures the temperature in the nip when the toner is fixed on the recording material.
° C. With the heating device of this configuration, if temperature control is performed at the temperature detected by the thermistor so as to keep the temperature in the nip at 130 ° C, the temperature control at 130 ° C is constant at continuous paper feeding started from the first state in the morning. It was possible. This time,
An input of about 400 W was required for the heating device to start up in 10 seconds from the first state in the morning to the fixable state. This is because the resistance heating element pattern is formed on the heating element opposite to the recording material sheet passing surface (nip forming surface). Thermal conductivity of alumina used as material (20 W /
It is considered that mK) is not so high and the thermal conductivity is poor.

[0065]

As described above, the heating device of the present invention enables quick start-up, quick start, and efficient transfer of heat energy into the nip to reduce power consumption. Accurate detection of the internal temperature eliminates the need for complicated control such as multi-step temperature control.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of an example of a heating device of the present invention.

FIG. 2 is a diagram showing a configuration of an example of a conventional heating device,
(A) is an enlarged cross-sectional schematic diagram of a main part, (b) is a schematic partially cutaway plan view of a heating body, and (c) is a schematic diagram showing details around the heating body.

3 is a graph showing a situation of temperature control performed in Comparative Example 1. FIG.

FIG. 4 is a schematic cross-sectional view showing the configuration of another example of the heating device, (a) is a diagram showing the overall configuration of the device,
(B) is a figure which shows the detail of the heating body periphery.

[Explanation of symbols]

2 Heater substrate (heater base material; ceramic base material) 3 Resistance heating element pattern 4 Conductor pattern 4a-4c Conductive pattern 5, 6 Power supply electrode pattern 7 Surface protective layer 8 Heat resistant film 9 Pressure roller 10 Heating body 11 Heating Body holder P Heated material (recording material) T Toner image N Fixing nip part (pressing nip part)

Claims (3)

[Claims] 1. A fixing film, a heating member fixedly supported on one surface side of the fixing film, and a pressure member provided on the other surface side of the fixing film so as to face the heating member. A heating device for heating and fixing a toner image by passing a recording material having a toner image through a nip portion formed by pressure contact between a heating member and a pressing member, wherein the heating member is made of aluminum nitride. A heating device characterized by. 2. The heating device according to claim 1, wherein a temperature detecting element for detecting the temperature of the heating body is arranged on the side of a nip portion formed by pressure contact between the heating body and the pressing member. 3. The heating device according to claim 1, wherein the resistance heating element of the heating element is arranged on a surface opposite to a nip portion side formed by pressure contact between the heating element and the pressing member.