JP2002246150A - Heating element, heating device, and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating element (a metal heater) 3, including a conductor base material 30, a first insulation layer 31 formed on a one surface side of the conductor base material, at least a heat generating resistance pattern 32 formed on the first insulation layer, a second insulating layer 35 formed, so as to cover the heat generating resistance pattern, and a third insulation layer 36 formed on an other surface side as an opposite surface side to the one surface side of the conductor base material, capable of having superior heat insulating property and good responsiveness of a temperature-detecting element. SOLUTION: The heating element includes a temperature-detecting element abutting area 39, which the temperature detecting element 37 for detecting a temperature of the heating element is abutted or arranged adjacent on the one surface side of the heating element 3. The insulating layer is not formed, only in the temperature detecting element abutting area. Or the insulating layer is formed to be thin, a surface roughness is reduced, or the thermal conductivity increases only in the temperature-detecting element abutting area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

More specifically, a heating base material (heater substrate)
The present invention relates to a heating element using a conductor, a heating device using the heating element, and an image forming apparatus including the heating apparatus as a heating and fixing unit for an unfixed image.

[0003]

2. Description of the Related Art Conventionally, in an image output apparatus such as a copying machine, a printer, a facsimile or the like using an appropriate image forming process such as electrophotography, electrostatic recording, or magnetic recording, a transfer method or a direct method is applied to a recording material. As a fixing device (image heating device) for fixing the formed and carried toner image on the recording material surface, a heating device of a heat roller type has been used.

This heating device of the heat roller type basically has a metal roller provided with a heater inside and a pressure roller having elasticity which presses against the metal roller, and a fixing nip portion (pressing nip) formed by the pair of rollers. The toner image is heated, pressed, and fixed by introducing a recording material as a member to be heated into the unit, and nipping, conveying, and passing the recording material.

However, in such a heating device of the heat roller type, it takes a very long time to raise the surface of the roller to the fixing temperature because the heat capacity of the roller is large. In addition, in order to quickly execute the image output operation, there is a problem that the roller surface must be adjusted to a certain temperature even when the apparatus is not used.

Therefore, as a heating device designed to solve these problems, Japanese Patent Application Laid-Open No. 63-313182 and Japanese Patent Application Laid-Open No.
There is a heating device of a film heating type disclosed in Japanese Patent No. 57878 and the like.

This film heating type heating apparatus is usually
A thin heat-resistant film and a heating element fixedly supported and arranged on one side of the film (hereinafter referred to as a heater)
And a pressurizing member disposed on the other side of the heater so as to face the heater, and to bring the member to be heated into close contact with the heater via the film.

A member to be heated and, in the case of an image heating apparatus, a toner image are formed and held between a film and a pressing member in a pressure contact nip formed by pressing the heater and the pressing member with the film interposed therebetween. By introducing and passing the recording material
The visible image carrying surface of the recording material is heated by a heater via the film, and thermal energy is applied to the unfixed image, so that the toner is softened and melted to heat and fix the image.

This film heating system is excellent in quick start performance, can greatly reduce the power consumption during standby, and can constitute an on-demand type heating device.

[0010]

Conventionally, in a fixing apparatus employing such a film heating method, for example, a ceramic base material such as alumina is often used as a substrate, for example, a ceramic heater as a heater. There are problems that the ceramic is brittle, the cost is high, and the ceramic is not suitable for bending and the like.

Therefore, Japanese Patent Application Laid-Open No. 9-244442,
In Japanese Patent Application Laid-Open No. 10-275671, a base material having insulating properties equivalent to that of a conventional ceramic base material is formed by forming an insulating layer on a metal material, and a heating resistance pattern, a conductive pattern, A heating element (conductor substrate heater, hereinafter referred to as metal heater) having an uppermost insulating sliding layer has been proposed.

By using a conductor substrate such as a metal substrate having a high thermal conductivity as the substrate material of the heater in this manner, the heater temperature can be made uniform over the entire area, and the temperature drop at both ends can be easily prevented. A good image can be formed without image unevenness such as fixing unevenness, gloss unevenness, and offset which are likely to occur over the length. In addition, the temperature rising speed of the heater can be improved, and the quick start property can be further improved. Furthermore, since the rupture strength of the metallic substrate itself is very high compared to ceramics, etc., there is no rupture of the substrate due to thermal stress or the like generated when the temperature of the heater rises rapidly. Problems can be suppressed, and productivity can be increased.

Further, in order to raise the temperature more quickly, it is necessary for the heater to efficiently supply the heat of the heater to the member to be heated. Improves the heat conduction on the surface side facing the member, the paper passing side side, the same applies hereinafter) to efficiently apply heat to the film and the recording material, and at the same time, the back side of the heater (the surface side facing the member to be heated) It is desirable that the opposite surface side, the non-sheet passing surface side, and the same hereinafter) have a heat insulating effect to minimize the escape of heat to the heater support and the like.

On the other hand, it is necessary to control the heater temperature to a desired temperature by contacting or approaching a thermistor or the like as a temperature detecting element for detecting the temperature of the heater and controlling the temperature to a desired temperature on the back surface side of the heater. However, if the thermistor contact area also has a heat insulating effect, the accuracy of detection of the thermistor detection temperature deteriorates, and so-called temperature ripple such as overshoot and undershoot of the heater temperature increases. In some cases, the temperature control becomes difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a metal heater having good workability, high strength and excellent thermal efficiency, and at the same time enabling accurate temperature control. An object of the present invention is to provide a heating device used and an image forming apparatus provided with the heating device as a heating and fixing unit for an unfixed image.

[0016]

According to the present invention, there is provided a heating element, a heating apparatus, and an image forming apparatus having the following constitutions.

(1) A conductive base material, a first insulating layer formed on one surface side of the conductive base material, at least a heating resistance pattern formed on the first insulating layer, A second insulating layer formed to cover the resistance pattern,
A heating element having a third insulating layer formed on the other surface side opposite to the one surface side of the conductive base material, and the temperature of the heating element on one surface side of the heating element. A heating element having a temperature detection element contact area in which a temperature detection element to be detected is in contact with or close to the temperature detection element, and wherein the insulating layer is not formed only in the temperature detection element contact area.

(2) A conductor substrate, a first insulating layer formed on one side of the conductor substrate, at least a heating resistor pattern formed on the first insulating layer, A second insulating layer formed to cover the resistance pattern,
A heating element having a third insulating layer formed on the other surface side opposite to the one surface side of the conductive base material, and the temperature of the heating element on one surface side of the heating element. An insulating layer film having a temperature sensing element contact area in which a temperature sensing element to be sensed is abutted or disposed in close proximity, and the insulating layer is formed only in the temperature sensing element abutting area in a region other than the temperature sensing element abutting area A heating element characterized by being formed thin with respect to its thickness.

(3) a conductor substrate, a first insulating layer formed on one surface side of the conductor substrate, at least a heat generating resistance pattern formed on the first insulating layer, A second insulating layer formed to cover the resistance pattern,
A heating element having a third insulating layer formed on the other surface side opposite to the one surface side of the conductive base material, and the temperature of the heating element on one surface side of the heating element. It has a temperature sensing element contact area where the temperature sensing element to be sensed is abutted or arranged close to it, and the surface roughness of the insulating layer only in the temperature sensing element abutting area, in an area other than the temperature sensing element abutting area. A heating element characterized in that the surface roughness of the formed insulating layer is reduced.

(4) A conductor substrate, a first insulating layer formed on one side of the conductor substrate, at least a heating resistor pattern formed on the first insulating layer, A second insulating layer formed to cover the resistance pattern,
A heating element having a third insulating layer formed on the other surface side opposite to the one surface side of the conductive base material, and the temperature of the heating element on one surface side of the heating element. It has a temperature sensing element contact area where the temperature sensing element to be sensed is abutted or arranged close to it, and the thermal conductivity of the insulating layer only in the temperature sensing element abutting area, in an area other than the temperature sensing element abutting area. A heating element characterized by increasing the thermal conductivity of the formed insulating layer.

(5) The heating device according to any one of (1) to (4), wherein the temperature detecting element is for detecting the temperature of the heating body and controlling the temperature to a desired temperature. body.

(6) On the first insulating layer, a heating resistor pattern and a conductive pattern for supplying power to the heating resistor pattern are formed (1) to (5).
The heating element according to any one of the above.

(7) The heating element according to any one of (1) to (6), wherein the second insulating layer side or the third insulating layer side is a heated member side.

(8) Any one of the above (1) to (7)
A heating device, comprising: a heating member according to any one of (1) to (3), wherein the heating member is heated by applying heat energy of the heating member directly or via another object.

(9) By passing the member to be heated through the nip portion between the heating member and the pressing member pressed against the member, heat energy of the heating member is applied to the member to be heated to heat the member to be heated. A heating device, wherein the heating member is the heating member according to any one of (1) to (7).

(10) A heating device that has a heating element and a film that slides on the heating element, and heats the member to be heated by the heat energy of the heating element via the film. A heating device according to any one of the above.

(11) A heating element, a film that slides on the heating element, and a pressure member that presses against the heating element via the film, and the member to be heated is placed in a nip between the film and the pressure member. A heating device for heating a member to be heated by passing heat energy of the heating member through a film to the member to be heated by passing the film, wherein the heating member is described in any one of (1) to (7). A heating device, which is a heating element.

(12) The object to be heated is a recording material carrying an image, and the image heating apparatus is an image heating device for heating the image by applying thermal energy of a heating body to the recording material.
The heating device according to any one of (1) to (11).

(13) The heating member is a recording material that carries an unfixed image, and is a heat fixing device that applies heat energy of a heating body to the recording material to thermally fix the image (7). The heating device according to any one of (1) to (11).

(14) In an image forming apparatus having an image forming means for forming and carrying an unfixed image on a recording material and a heating and fixing means for thermally fixing the unfixed image formed and carried on the recording material, the heat fixing means Is the heating device according to any one of (7) to (11).

[Operation] 1) Since the heating element uses a conductive base material, it has the above-mentioned features of the metal heater sufficiently.

The first insulating layer serves to ensure electrical insulation between the conductor substrate and the heating resistor pattern.

When the heating element is of a "surface heating type" in which the surface side of the second insulating layer faces the surface of the heating element facing the member to be heated, the second insulating layer functions as a surface protection layer of the heating element. Then, the third insulating layer on the back side of the heating element functions as a heat insulating layer for minimizing the escape of heat to the heating element support or the like. For this purpose, the third insulating layer is formed as a heat insulating layer having, for example, a small thermal conductivity or a large thickness with respect to the second insulating layer.

Conversely, in the case where the heating element is of a “backside heating type” in which the third insulating layer surface side is the heating element surface side facing the member to be heated, the third insulating layer is formed of the heating element. The second insulating layer on the back side of the heating element functions as a surface protection layer, and functions as a heat insulating layer that minimizes the escape of heat to the heating element support and the like. For this purpose, the second insulating layer is made to have a low thermal conductivity, a large thermal conductivity, and the like, for example, as a heat insulating layer with respect to the third insulating layer.

2) In the above-mentioned heating element of the surface heating type or the backside heating type, in the region where the temperature sensing element of the third or second insulating layer to be the heat insulating layer on the back side of the heating element abuts, the insulating layer is Eliminating and forming an insulating layer in the area other than the temperature sensing element contact area achieves a heat insulating effect on the heating element support of the heating element and at the same time does not hinder the heat transfer to the temperature detection element. Responsiveness can be obtained and thermal efficiency can be increased, which is effective in shortening the start-up time and reducing power consumption, and at the same time enables accurate temperature control.

2) Alternatively, the thickness of the third or second insulating layer serving as the heat insulating layer on the back surface of the heating element is reduced only in the area other than the area where the temperature sensing element is in contact. In addition to achieving the heat insulating effect of the heating element on the heating element support, the heat conduction to the temperature detection element can be improved by securing the minimum withstand voltage in the temperature detection element section, and the configuration of the temperature detection element itself Can be designed relatively freely.

3) Alternatively, the withstand voltage in the temperature sensing element contact area can be ensured only by adjusting the surface roughness of the temperature sensing element contact area of the third or second insulating layer serving as the backside heat insulating layer of the heating element. At the same time, the thermal conductivity to the temperature detecting element is improved, and the temperature control can be performed more accurately.

4) Alternatively, the withstand voltage in the temperature sensing element contact area can be ensured only by adjusting the thermal conductivity of the temperature sensing element contact area of the third or second insulating layer serving as the back surface heat insulating layer of the heating element. At the same time, the thermal conductivity to the temperature detecting element is improved, and the temperature control can be performed more accurately.

[0039]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] (1) Example of Image Forming Apparatus FIG. 1 is a schematic structural model diagram of an example of an image forming apparatus. The image forming apparatus of this embodiment is, for example, a copying machine, a printer, a facsimile, or the like that uses a transfer type electrophotographic process.

Reference numeral 101 denotes a drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) as an image carrier. The photosensitive drum 101 is rotatably supported in the image forming apparatus main body M, and is rotationally driven at a predetermined process speed in a clockwise direction of an arrow R1 by a driving unit (not shown).

Around the photosensitive drum 101, a charging roller (charging device) 102, an exposing unit 103, a developing device 104, and a transfer roller (transfer device) are arranged in this order along the rotation direction.
105 and a cleaning device 106 are arranged.

In the lower part of the image forming apparatus main body M,
A paper feed cassette 107 containing a sheet-like recording material (transfer material) P such as paper is arranged. Then, in order from the upstream side along the transport path of the recording material P, the paper feed roller 115, the transport roller 108, the top sensor 109, the transfer roller 10
5, a conveyance guide 110, a heat fixing device 111, a fixing paper discharge roller 112, a discharge roller 113, and a paper discharge tray 114 are arranged.

The photosensitive drum 101 rotated and driven in the direction of arrow R1 by the driving means is uniformly charged to a predetermined polarity and a predetermined voltage by the charging roller 102.

The surface of the charged photosensitive drum 101 is subjected to image exposure L based on image information by exposure means 103 such as a laser optical system, and the charge of the exposed portion is removed to form an electrostatic latent image. You.

The electrostatic latent image is developed by the developing device 104. The developing device 104 has a developing roller 104a, and applies a developing bias to the developing roller 104a to attach toner to the electrostatic latent image on the photosensitive drum 101 to develop (visualize) as a toner image.

The toner image is transferred to a recording material P such as paper by a transfer roller 105. The recording material P is stored in a paper feed cassette 107, fed by a feed roller 115, transported by a transport roller 108, and transferred to the photosensitive drum 101 and a transfer roller 1 via a top sensor 109.
05 is transferred to the transfer nip portion. At this time, the leading end of the recording material P is detected by the top sensor 109,
Synchronization with the toner image on the photosensitive drum 101 is achieved. A transfer bias is applied to the transfer roller 105, whereby the toner image on the photosensitive drum 101 is transferred to a predetermined position on the recording material P.

The recording material P carrying an unfixed image on the surface by transfer is transferred to the heat fixing device 1 along a conveyance guide 110.
Then, the unfixed toner image is heated and pressed to be fixed on the surface of the recording material P.

The recording material P having the toner image fixed thereon is conveyed by a fixing discharge roller 112 and discharged by a discharge roller 113 onto a discharge tray 114 on the upper surface of the image forming apparatus main body M.

On the other hand, the photosensitive drum 101 after the transfer of the toner image
The toner remaining on the surface without being transferred to the recording material P (transfer residual toner) is removed by the cleaning blade 106a of the cleaning device 106, and is used for the next image formation.

By repeating the above operations, images can be formed one after another.

(2) Heat Fixing Device 111 The heat fixing device 111 in this embodiment is a pressure roller driving type.
It is a tensionless type film heating type heating device. FIG. 2 is a schematic configuration diagram of the device 111. FIG. 3 is a partially enlarged model view of the fixing nip portion.

Reference numeral 1 denotes a cylindrical (endless) thin heat-resistant film (fixing film), 2 denotes a heater support (heater support) having a substantially semicircular cross section in cross section, and 3 denotes a heater support 2. The metal heater 4 as a supported heating element is a pressure roller as a pressure member that forms a fixing nip N by pressing against the heater 3 with the film 1 interposed therebetween.

The cylindrical film 1 is externally fitted to a heater support 2 including a heater 3. The inner peripheral length of the cylindrical film 1 and the outer peripheral length of the heater support 2 including the heater 3 are equal to the film 1. Is made larger, for example, by about 3 mm, so that the film 1 is loosely fitted to the heater supporting member 2 with a sufficient peripheral length.

The film 1 has a film thickness of 100 in order to reduce the heat capacity and improve the quick start property.
μm or less, preferably 50 μm or less 20 μm or more heat-resistant single layer of PTFE, PFA, FEP, or polyimide, polyamideimide, PEEK, PES, PP
A composite layer film in which the outer peripheral surface of S or the like is coated with PTFE, PFA, FEP, or the like can be used. In this example, a polyimide film having an outer peripheral surface coated with PTFE was used.

The heater support 2 is a member having a substantially semicircular trough-shaped cross section, and is a member having heat insulation and rigidity. An elongated and shallow groove-shaped counterbore 21 into which the heater 3 can be fitted is provided along the length of the lower surface of the heater support 2 along the length thereof. Are fitted and supported by the heater support 2. The heating body support 2 is made of a heat-resistant resin such as PPS, a liquid crystal polymer, or a phenol resin into which glass is added to increase the strength. These resins are used by being injected into a mold for molding.

The heater 3 is a metal heater (conductor substrate heater) as a heating element according to the present invention, and is a member having a long and thin plate shape having a longitudinal direction perpendicular to the drawing and having a low heat capacity as a whole. The structure of the heater 3 is described in the following (3).
As will be described in detail, the power is supplied to the heating resistance pattern of the heater 3 to quickly generate heat and raise the temperature, and the temperature is controlled to a predetermined fixing temperature by a temperature control system. More specifically, heating element 3
The output of the thermistor 37 provided above is A / D-converted and taken into a control circuit (CPU) 10, and based on the information, the AC voltage applied to the heating resistance pattern of the heater 3 by the triac 11 is controlled in phase and wave number. This is performed by controlling the heater energization power by using the above method.

The pressure roller 4 is composed of a core 41 and a heat-resistant rubber elastic layer 42 having good releasability such as silicon rubber provided concentrically and integrally with the core. It is rotatably supported between chassis side plates (not shown) via bearings.

On the upper side of the pressure roller 4, the above-described assembly of the film 1, the heater support 2, and the heater 3 is opposed to each other with the heater 3 side facing downward. The heater 3
Is pressed against the upper surface of the pressure roller 4 with a predetermined pressing force against the elasticity of the rubber elastic layer 4b with the film 1 interposed therebetween. Thus, the fixing nip portion N having a predetermined width with the film 1 interposed between the heater 3 and the elastic pressure roller 4 is formed.
Is formed.

The pressure roller 4 is driven to rotate counterclockwise at a predetermined peripheral speed by a driving means (not shown). The rotation of the pressure roller 4 causes a rotational force to act on the cylindrical film 1 due to the frictional contact between the outer surface of the roller 4 and the outer surface of the film 1 at the fixing nip portion N. At the fixing nip portion N, the heater 3 is rotated around the outer periphery of the heating body support 2 at a peripheral speed substantially corresponding to the rotational peripheral speed of the pressure roller 4 while sliding in close contact with the downward surface of the heater 3 in the clockwise direction of the arrow. (Pressurized roller drive system).

The heating body support 2 is provided with the rotating film 1
It also functions as a guide member. Further, by interposing a lubricant such as heat-resistant grease between the downward surface of the heater 3 and the inner surface of the film 1, the rotation of the film 1 can be made smoother.

The pressure roller 4 is driven to rotate, and the cylindrical film 1 is rotated accordingly. When the heater 3 is energized as described later, the heat generated by the heater 3 causes the fixing nip N to reach a predetermined temperature. In the state where the temperature is adjusted by rising, the recording material P carrying the unfixed toner image t is introduced between the film 1 in the fixing nip portion N and the pressure roller 4,
In the fixing nip portion N, the toner image carrying surface side of the recording material P is in close contact with the outer surface of the film 1, and the fixing nip portion N is conveyed together with the film. In this nipping and conveying process, the heat of the heater 3 is applied to the recording material P via the film 1, and the unfixed toner image t on the recording material P is heated and fused. When the recording material P passes through the fixing nip portion N, the recording material P is conveyed with a curvature separated from the outer surface of the rotating film 1.

(3) Heater 3 The heater 3 is a metal heater as a heating element according to the present invention, and FIG.
(B) is a plan view showing the heating resistor pattern exposed in (a) except for the second insulating layer, and (c) is a heater 3
3 is a plan view of the back side of FIG.

The heater 3 is made of a conductive base material (conductive base material).
30, an insulating glass layer 31 as a first insulating layer formed on one surface side (first surface side) of the conductor base material 30, and two parallel lines formed on the first insulating layer. And the two conductor patterns 33.3 as power supply electrodes for supplying power to the heat generating resistive patterns.
3, a conductive pattern 34 as a folded electrode, an insulating glass layer 35 as a second insulating layer formed so as to cover the heating resistor pattern 32, and a side opposite to the one side of the conductive base 30. And an insulating glass layer 36 as a third insulating layer formed on the other surface side (second surface side).

The heater 3 of this embodiment is a “surface heating type”.
The side of the second insulating layer 35 is the front side of the heater in contact with the back surface of the film 1, and the side of the third insulating layer 36 is the back side of the heater. As shown in FIG. 3, the heater 3 is supported by being fitted into the counterbore portion 21 of the heater support 2 with its second insulating layer 35 side, which is the surface side, exposed downward.

The conductive base material 30 is made of SUS4 which easily matches the expansion coefficient with the glass layers 31, 35 and 36 as insulating layers.
A metal such as 30 was used. The thickness of the substrate 30 was about 0.4 to 0.6 mm in this embodiment.
If the thickness of the substrate 30 is too thin, warpage is likely to occur due to the difference in thermal expansion coefficient between the substrate and the insulating glass layer after printing and firing, and the substrate 30 is easily bent, so that handling during the manufacturing process becomes difficult. . On the other hand, if the thickness is too large, the heat capacity of the base material itself becomes large, so that it is difficult to delay the start-up time of the heater and to control the temperature control itself. This leads to image problems such as fixing failure, uneven gloss, and offset.

The insulating glass layer 31 as the first insulating layer is formed over substantially the entire area on one side of the conductor substrate 30. The insulating glass layer 31 is formed by, for example, printing and applying a glass paste material on the surface of the conductive base material 30 by screen printing and baking.

On the insulating glass layer 31, heat generating resistance patterns 32 and 32, two conductor patterns 33 and 33 as power supply electrodes, and a conductive pattern 34 as a folded electrode are provided.
Is formed, electrical insulation from the conductive base material 30 is ensured.

Insulating glass layer 31 as first insulating layer
Is 30 μm in order to have a breakdown voltage of 1.5 kV or more.
In order to prevent pinholes, it is preferable to employ a method of printing a plurality of times to prevent pinholes. Further, in order to increase the adhesiveness between the conductive base material 30 and the insulating glass layer 31, the conductive base material 30 is roughened by sand blasting, etching or the like, and degreased.
It is good to print

The energized heating resistance pattern 32 is, for example, A
It is formed by printing a predetermined pattern by screen printing or the like using a paste of an electric resistance material (heating resistor, energization heating resistor) such as g / Pd (silver palladium) and baking.

The conductive patterns 33 and 34 are, for example,
It is formed by printing a predetermined pattern using a paste of a conductor such as Ag (silver) by screen printing or the like, and baking it.

Insulating glass layer 35 as second insulating layer
Serves as a heater surface protection layer that covers a part of the heat generating resistance patterns 32, 32, a conductive pattern 34 as a folded electrode, and two conductive patterns 33 as a power supply electrode and protects them. I have. This insulating glass layer 3
5 is formed by, for example, printing and applying a glass paste material on the surface of the conductive base material 30 by screen printing and firing.

The insulating glass layer 36 serving as a third insulating layer functions as a heat insulating layer on the back surface of the heater 3, and is provided on the other surface of the conductive base material 30 for controlling the power supply to the heater. , Except for the contact area 39 of the thermistor 37. The insulating glass layer 36 is formed by, for example, printing and applying a glass paste material on the surface of the conductive base material 30 by screen printing, and baking.

The thermistor 37 is disposed in direct contact with the surface of the conductive substrate 30 in the contact area 39 where the insulating glass layer 36 is not provided on the back side of the heater. The thermistor 37 is connected to the control circuit 10 via a lead wire 37a (secondary circuit DC).

The thermoswitch 3 as a safety device
8 is disposed in contact with or close to an insulating glass layer 36 as a third insulating layer. 38a is a lead wire of the thermo switch 38. The thermo switch 38 is connected to a power supply circuit (1
The next circuit system AC) 11 is connected in series.

When power is supplied from the power supply circuit 11 between the two conductive patterns 33 serving as power supply electrodes of the heater 3, the heat generating resistor patterns 32 generate heat over the entire length, and the entire heater 3 rapidly rises in temperature. I do.

In this embodiment, the thermistor 37 is
This is a thermistor composed of thermistor beads protected by glass in order to ensure the withstand voltage of the heater 3 with respect to the conductor substrate 30. The temperature of the heater 3 is detected by measuring the resistance value of the thermistor beads. The temperature of the heater 3 is controlled to a predetermined value by controlling the electric power applied to the heating resistor patterns 32 of the third heater.

In addition to the configuration of the present embodiment, for example, a thermistor or a thermocouple covered with an insulating protection sheet may be used.

Usually, SUS430 used as a conductive base material
And the thermal conductivity of the glass layer used for the insulating layer is about one digit,
Since SUS430 is better, there is no particular restriction on the magnitude relation of the thermal conductivity of each glass layer, and a sufficient heat insulating effect can be obtained only by interposing the insulating glass layer on the back surface of the conductive base material. In order to transfer heat to the front side and enhance the heat insulating effect on the back side, in the heater 3 of the present embodiment, the thermal conductivity of the first insulating glass layer 31 is set to K1, and the thermal conductivity of the second insulating glass layer 35 is set to K1. When the rate is K2 and the thermal conductivity of the third insulating glass layer 36 is K3, the respective relations are K2> K.
3 (= K1).

The thermal conductivity of each insulating glass layer is specifically adjusted as desired by adjusting the glass composition, additives and the like.
In the present embodiment, the second insulating glass layer 35 having a thermal conductivity K2 of about 1.1 to 1.5 [W / m · K] is used. 36 and 31, the thermal conductivity K3 and K1 are about 0.8 to 1.0 [W / m
[K] or so. The conductor base 30 has a thermal conductivity of about 20 to 30 [W / m · K].

FIG. 5A is a schematic cross-sectional view of a heater at a portion where a third insulating glass layer 36 which is a heat insulating layer on the back surface side of the heater 3 is provided, and FIG. 5B is a portion where the third insulating glass layer 36 is not provided. FIG. 3 is a schematic cross-sectional view of a heater in a contact area 39 of the thermistor 37, and schematically shows the state of heat transfer Q1 to the front side and heat transfer Q2 and Q3 to the back side in each heater portion.

That is, since the thermal conductivity of the insulating glass layer of the heater 3 is different from the thermal conductivity of the conductive substrate 30 by about one digit, the heater 3 of the front surface heating type of the present embodiment has the rear surface side. Third insulating glass layer 36 functioning as a heat insulating layer
By contacting the heating member support 2 with the heating member support 2, the heat transfer to the heating member support 2 can be suppressed by the heat insulation effect, and the heater 3 can be efficiently heated, and at the same time, the temperature detecting element can be used. The thermistor 37 is disposed in direct contact with the surface of the conductive substrate 30 in the contact area 39 where the insulating glass layer 36 is not provided on the back surface of the heater.
It can be seen that the heat transfer Q3 to the thermistor 37 can be made larger than Q2, and the temperature control can be performed more accurately.

FIG. 6 shows that the thermistor 37 as a temperature detecting element is brought into direct contact with the surface of the conductor substrate 30 in the contact area 39 where the insulating glass layer 36 is not provided on the back side of the heater as in this embodiment. The case A is disposed, and the case where the insulating glass layer 36 is formed over the entire area on the rear surface side of the heater and the thermistor 37 serving as a temperature detecting element is brought into contact with the insulating glass layer 36 is disposed as a comparative example. The comparison of the output of the thermistor detection temperature in the above shows that the rise time and the response of the detection temperature are clearly different from each other.

In this experiment, the same conditions (input power: 1000 W, target temperature control temperature: 200 ° C., process speed: 150 mm /
sec).

In the case of this experiment, the start-up time was about 3.7 seconds in the case of the comparative example B, but was 2.4 seconds in the case of the present example A, which was clearly thermistor detection. It can be seen that the speed is improved.

As described above, the insulating glass layer 36 is formed in the contact area of the heater support other than the thermistor contact area 39, and the insulating glass layer is not formed only in the thermistor contact area 39. Since the heat transfer to the body support 2 is suppressed as much as possible and the insulating glass layer 36 that prevents heat transfer only in the thermistor contact area 39 is not formed, the temperature of the heater 3 can be more accurately detected and controlled, so that the consumption is reduced. With low power consumption and accurate temperature control, it is possible to control with less temperature ripple.
Image defects such as offset can be suppressed.

[Second Embodiment] FIG. 7 is a schematic diagram of a main part of this embodiment. In the present embodiment, the third insulating glass layer 36 is formed on the entire area on the back surface side of the heater in the surface heating type heater 3 in the first embodiment, but the third insulating glass layer 36 corresponding to the thermistor contact area 39 is formed. The thickness is formed smaller than the thickness of the insulating glass layer in other portions.

For example, in this embodiment, the thickness of the insulating glass layer 36, which is the backside heat insulating layer of the heater 3, is formed to be about 80 to 100 μm in order to have a sufficient heat insulating effect. In the present embodiment, it is formed by three-layer coating. Therefore, after forming one or two insulating glass layers in the thermistor contact area 39, for example, the thermistor contact area 39 is formed.
And an insulating glass layer is formed over the entire area of the heater.

By forming in this manner, only the glass coat in the thermistor contact area 39 can be easily formed thin.

By forming the insulating glass layer 36 thin only in the thermistor contact area 39 in this way, it is not necessary to impart heat to the structure of the thermistor itself, and the structure of the thermistor 37 can be configured more freely. Sufficient responsiveness can be obtained by improving the heat capacity and thermal conductivity of the thermistor itself while designing it.

In the case of the structure of this embodiment, as the temperature detecting element, a conductive pattern may be formed by printing and a chip type thermistor may be mounted, or a printed resistor may be formed directly by printing.

[Third Embodiment] FIG. 8 is a schematic diagram of a main part of this embodiment. In the present embodiment, the third insulating glass layer 36 as a heat insulating layer is formed on the entire surface on the back side of the heater in the surface heating type heater 3 in the first embodiment. The surface roughness of the glass in the glass layer portion is smaller than the surface roughness of the glass in the other portion of the insulating glass layer.

Specifically, when the insulating glass layer 36 is formed by printing, the mesh of the screen is adjusted to reduce the surface roughness of the insulating glass layer 36 except for the thermistor contact area 39 and the area other than the contact area 9. The adjustment is made so that the thermistor contact area 39 has a small surface roughness, and the other areas have a large surface roughness.

In the present embodiment, the thermistor contact area 39 is formed to have a surface roughness Ra of about 0.07 to 0.1 μm.
9, the surface roughness Ra is about 0.5 to
It is formed to have a thickness of about 2.0 μm.

As a result, a more accurate temperature can be detected by reducing the contact thermal resistance of the thermistor 37 in the thermistor contact area 39 and increasing the adhesion, and at the same time, the glass surface roughness other than the thermistor contact area 39 increases. By doing so, it is possible to enhance the heat insulating effect by reducing the contact area between the heater 3 and the heater support 2.

By adopting this structure as described above, the heat insulation is excellent, the heat transfer from the heater 3 to the heater support 2 is minimized, and the excellent heater structure is formed only in the thermistor contact area 39. Since the transmission can be improved, the thermistor responsiveness can be improved, and the temperature of the heater 3 can be detected and controlled more accurately. Therefore, power consumption can be suppressed, and at the same time, control with less temperature ripple can be performed by accurate temperature control. This makes it possible to suppress image defects such as offset.

[Fourth Embodiment] FIG. 9 is a schematic diagram of a main part of this embodiment. In the present embodiment, the third insulating glass layer 36 as a heat insulating layer is formed on the entire surface on the back side of the heater in the surface heating type heater 3 in the first embodiment. The thermal conductivity of the glass layer portion is higher than the thermal conductivity of the insulating glass layer in other portions.

In this embodiment, the thermistor contact area 39
Then, a high thermal conductivity glass is formed by printing, and then, other than the thermistor contact area 39, a glass having a lower thermal conductivity than the high thermal conductivity glass used in the thermistor contact area is printed.

Specifically, a material having a thermal conductivity of about 0.8 [W / m · K] is used in the thermistor contact area 39, and about 1.3 to 1.. 5 [W /
m · K].

As described above, by forming the high thermal conductive insulating glass layer only in the thermistor contact area 39 and forming the low thermal conductive insulating glass layer in the area other than the thermistor contact area, the thermal conductivity of the thermistor portion is reduced. , The temperature can be detected more accurately, and at the same time, the thermal conductivity of the insulating glass layer other than the thermistor portion is reduced, so that the escape of heat from the heater 3 to the heater support 2 can be suppressed. Improve thermal efficiency,
By controlling the power consumption at the same time as the temperature control with high accuracy, it is possible to perform control with less temperature ripple, and it is possible to suppress image defects such as offset.

[Fifth Embodiment] This embodiment is an example of a "backside heating type" heater. FIG. 10A is a cross-sectional model view, FIG. 10B is a plan view of the front side, and FIG. () Is a plan view of the back side. This heater 3 is such that the surface of the third insulating glass layer 36 of the surface heating type heater 3 of the first embodiment is on the side of the surface of the heater facing the member to be heated.

In the case of this backside heating type heater 3, the third insulating glass layer 36 functions as a surface protection layer of the heater 3, and the second insulating glass layer 35 on the backside of the heater 3 Function as a heat insulating layer that minimizes the escape of heat to the like. Further, it is better to use a high thermal conductivity type for the first insulating glass layer 31 in order to efficiently transmit the heat of the heating element to the base material side. In this embodiment, the magnitude of the thermal conductivity is represented by K3 = It is preferable to form them so that K1> K2. In the case of this backside heating type heater 3, when forming the second insulating glass layer 35 as the heater backside heat insulating layer, the thermistor contact area 39 of the third insulating glass layer 36 in the second embodiment described above. The second insulating glass layer 35 is formed thin only in the thermistor contact area 39 in the same manner as described above.

When this configuration is adopted, the heating resistor 32
Since the positions of the thermistor 32 and the thermistor 37 are close to each other, the temperature of the heater can be more accurately detected and controlled, and appropriate temperature control can be performed.

[Sixth Embodiment] FIG. 11 is a schematic diagram of a main part of this embodiment. In the present embodiment, when forming the second insulating glass layer 35 as a heater back insulating layer in the backside heating type heater 3 in the fifth embodiment, the third insulating glass layer in the second embodiment described above. In the same manner as the thermistor contact area 39 of 36, the surface roughness is made smaller only in the thermistor contact area 39 than in other portions of the insulating glass layer 35.

When this configuration is adopted, the heating resistor 32
32 and the thermistor 37 are close to each other.
Temperature can be detected and controlled more accurately, and appropriate temperature control can be performed. As a result, control with even smaller temperature ripples can be performed, and image defects such as offset can be suppressed.

[Seventh Embodiment] FIG. 12 is a schematic diagram of a main part of this embodiment. In this embodiment, when forming the second insulating glass layer 35 as the heater back surface heat insulating layer in the backside heating type heater 3 in the fifth embodiment, the third insulating glass layer in the third embodiment described above. In the same manner as the thermistor contact area 39 of 36, the thermal conductivity is made higher only in the thermistor contact area 39 than in other portions of the insulating glass layer 36.

When this configuration is adopted, the heating resistor 32
32 and the thermistor 37 are close to each other.
Temperature can be detected and controlled more accurately, and appropriate temperature control can be performed. As a result, control with even smaller temperature ripples can be performed, and image defects such as offset can be suppressed.

[Others] 1) With respect to the contact area of the thermoswitch 38 as a safety device disposed in contact with or close to the heater 3, the same treatment configuration as that of the thermistor contact area 39 described above may be adopted. it can.

2) In a heating device of a film heating system, an endless belt-shaped film may be stretched by applying tension to the film and driven to rotate. Further, an apparatus may be used in which a long end film wound in a roll is used, and the film is run at a predetermined speed from a pay-out shaft side to a take-up shaft side via a heater.

3) The heating element of the present invention can be applied not only to a heating apparatus of a film heating system, but also to a heating apparatus in which a heating element supported by a heating element support is brought into direct contact with a member to be heated and heated. Of course, you can.

4) The heating apparatus of the present invention is not only an image heating and fixing apparatus, but also, for example, an image heating apparatus for heating a recording material carrying an image to improve the surface properties such as gloss, and performing a provisional deposition process. An image heating device, a heating device for feeding and drying a sheet, a laminating process, a hot press process for removing wrinkles, a heater used for a heating device for drying used in an ink jet printer, or the like. Of course, it can be widely used as a heating device.

[0112]

As described above, according to the present invention,
With respect to a metal heater using a conductor substrate as the material of the heating body substrate, excellent heat insulation properties and good temperature sensing element responsiveness (thermistor responsiveness) can be obtained. By suppressing the escape of heat to the back side of the heating body and efficiently transmitting it to the front side of the heating body, the strength was high, the heat insulation was excellent, and the heating device could be realized more easily and at lower cost. The temperature of the heating element can be more accurately detected and controlled, and appropriate temperature control becomes possible.This makes it possible to control the temperature with less temperature ripple and suppress image defects such as offset in the heat fixing device. As a result, a heat fixing device having a good fixing property and an excellent quick start property can be realized more easily and at a lower cost.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram of a film fixing type heat fixing device.

FIG. 3 is a partially enlarged model view of a fixing nip portion.

FIG. 4 is a structural explanatory view of a heater (surface heating type).

FIG. 5 is a schematic diagram of a heater heat transfer.

FIG. 6 is a diagram showing the thermistor response characteristics of the example and the comparative example.

FIG. 7 is a structural explanatory view of a heater according to a second embodiment.

FIG. 8 is a structural explanatory view of a heater according to a third embodiment.

FIG. 9 is a structural explanatory view of a heater according to a fourth embodiment.

FIG. 10 is a structural explanatory view of a heater (backside heating type) according to a fifth embodiment.

FIG. 11 is a structural explanatory view of a heater according to a sixth embodiment.

FIG. 12 is a structural explanatory view of a heater according to a seventh embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 {Film} 2 Heating body support 3} Heating body 4} Pressure roller 30} Conductor base material 31} First insulating layer 32} Heating resistance pattern (heating resistor) 33} Conduction Pattern (feeding electrode pattern) 34 conductive pattern (return conductive pattern) 35 second insulating layer 36 third insulating layer 37 thermistor 38 thermoswitch 39 thermistor contact area

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/20 109 G03G 15/20 109 H05B 3/18 H05B 3/18 3/20 330 3/20 330 F Term (reference) 2F056 QF02 QF08 2H033 AA18 BA25 BA32 BE03 3K034 AA02 AA04 AA10 AA16 AA20 AA34 AA37 BA05 BA13 BA17 BB02 BB05 BB14 BC04 BC12 BC16 CA02 CA17 CA32 DA02 DA05 HA01 HA10 JA01 A02 ACA AA ACA A81A GA06 3K092 PP18 QA05 QB31 QB43 QB64 RF03 RF09 RF17 RF22 UA01 UA17 VV16 VV35

Claims (14)

[Claims] 1. A conductive base material, a first insulating layer formed on one side of the conductive base material, at least a heat generating resistance pattern formed on the first insulating layer, and a heat generating resistance A heating element having a second insulating layer formed so as to cover a pattern, and a third insulating layer formed on the other surface side opposite to the one surface side of the conductor substrate. Having a temperature sensing element contact area in which a temperature sensing element for sensing the temperature of the heating element is abutted or disposed on one side of the heating element, and the insulating layer is provided only in the temperature sensing element abutting area. A heating element characterized by not being formed. 2. A conductive base material, a first insulating layer formed on one side of the conductive base material, at least a heat generating resistance pattern formed on the first insulating layer, and a heat generating resistance A heating element having a second insulating layer formed so as to cover a pattern, and a third insulating layer formed on the other surface side opposite to the one surface side of the conductor substrate. Having a temperature sensing element contact area in which a temperature sensing element for sensing the temperature of the heating element is abutted or disposed on one side of the heating element, and the insulating layer is provided only in the temperature sensing element abutting area. A heating element characterized in that it is formed thinner than the thickness of an insulating layer formed in a region other than the contact region of the temperature detecting element. 3. A conductive base material, a first insulating layer formed on one side of the conductive base material, at least a heat generating resistance pattern formed on the first insulating layer, and a heat generating resistance A heating element having a second insulating layer formed so as to cover a pattern, and a third insulating layer formed on the other surface side opposite to the one surface side of the conductor substrate. Having a temperature sensing element contact area in which a temperature sensing element for sensing the temperature of the heating element is abutted or arranged on one surface side of the heating element, and the insulating layer only in the temperature sensing element abutting area. A heating element characterized in that the surface roughness is made smaller than the surface roughness of an insulating layer formed in a region other than the temperature sensing element contact region. 4. A conductive base material, a first insulating layer formed on one side of the conductive base material, at least a heat generating resistance pattern formed on the first insulating layer, and a heat generating resistance A heating element having a second insulating layer formed so as to cover a pattern, and a third insulating layer formed on the other surface side opposite to the one surface side of the conductor substrate. Having a temperature sensing element contact area in which a temperature sensing element for sensing the temperature of the heating element is abutted or arranged on one side of the heating element, and the insulating layer is provided only in the temperature sensing element abutting area. A heating element characterized in that the thermal conductivity is higher than the thermal conductivity of an insulating layer formed in a region other than the temperature sensing element contact region. 5. The heating element according to claim 1, wherein the temperature detection element is for detecting a temperature of the heating element and controlling the temperature to a desired temperature. 6. The heat-generating resistor pattern and a conductive pattern for supplying power to the heat-generating resistor pattern are formed on the first insulating layer. Heating body. 7. The heating element according to claim 1, wherein the second insulating layer side or the third insulating layer side is a member to be heated. 8. A heating member according to claim 1, wherein the heating member is heated by applying heat energy of the heating member directly or through another object to the heating member. A heating device. 9. Heating for heating a member to be heated by applying heat energy of the heating member to the member to be heated by passing the member to be heated through a nip portion between the heating member and a pressing member pressed against the member. A heating apparatus, wherein the heating element is the heating element according to any one of claims 1 to 7. 10. A heating device comprising a heating element and a film sliding on the heating element, wherein the heating element heats a member to be heated by thermal energy of the heating element via the film. A heating device comprising the heating element according to any one of the above. 11. A heating element, a film that slides on the heating element, and a pressing member that presses against the heating element via the film, wherein the member to be heated passes through a nip portion between the film and the pressing member. A heating device that applies heat energy of the heating element to the member to be heated through the film to thereby heat the member to be heated, wherein the heating element is the heating element according to any one of claims 1 to 7. A heating device, comprising: 12. The image heating apparatus according to claim 7, wherein the member to be heated is a recording material carrying an image, and an image heating apparatus for applying a thermal energy of a heating body to the recording material to heat the image. A heating device according to any one of the preceding claims. 13. The heat fixing device according to claim 7, wherein the member to be heated is a recording material carrying an unfixed image, and the heat fixing device applies heat energy of a heating body to the recording material to thermally fix the image. The heating device according to any one of items 1 to 11. 14. An image forming apparatus comprising: an image forming means for forming and supporting an unfixed image on a recording material; and a heat fixing means for thermally fixing the unfixed image formed and supported on the recording material. An image forming apparatus, comprising: the heating apparatus according to claim 7.