JPH11231696A - Heating body, heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lowering of a spring constant caused by the temperature rise of a pressure spring and to eliminate fautly conduction between an electrode part and the pressure spring by arranging a heat radiation member at a part corresponding to a contact part between the electrode part and the pressure spring functioning as the contact. SOLUTION: A ceramic heater 1 functioning as the heating body is equipped with a heating body base plate 11, a resistance heating element 12 provided on the surface side of the base plate 11, electrode patterns 13 and 14 for feeding power to the heating element 12 and a conduction path pattern 15, etc. By fitting a connector for an AC line 31 to the extension arm part 2b of a heating body supporting body 2, two pressure springs 32 being the electric contact inside the connector 31 respectively press-contact with the electrode patterns 13 and 14 of the heating body 1. The extension arm part 2b of the supporting body 2 being a part corresponding to the minute contact part between the patterns 13 and 14 of the heating body 1 and the spring 32 on the connector 31 side is constituted of material excellent in heat radiation such as aluminum so as to be the heat radiation member 41.

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 element provided with a heating element, having an electrode section on a heating element substrate which is heated by the heat generated by the heating element, and bringing a pressure spring as an electrical contact into contact with the electrode section; The present invention relates to a heating device having the heating element, and an image forming apparatus including the heating device as an image heating and fixing unit.

[0003]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, an unfixed toner image formed and carried on a recording material by an appropriate image forming method such as an electrophotographic method or an electrostatic recording method is recorded. As a fixing device which is a heating device for thermally fixing a material, a heat roller type device has been widely used.

This heat roller type fixing device has a heat roller (fixing roller) which is heated and regulated to a predetermined fixing temperature by a heat source such as a halogen lamp, and an elastic pressure roller pressed against the heat roller. The recording material, which is the material to be heated, is introduced into the press-contact nip portion (fixing nip portion) of the two rollers and nipped and conveyed. Things.

However, in this heating device of the heating roller type (fixing device), since the heating roller has a large heat capacity,
It takes a considerable waiting time for the heating roller to rise to the specified temperature after turning on the power. After the temperature has risen, the image forming apparatus must wait for the image to be output immediately at any time. During the operation, the heat source of the heating roller must be energized to control the temperature of the heating roller to maintain a high temperature at all times, which consumes a large amount of energy. There were problems such as raising the temperature.

Therefore, recently, a heating device of a film heating type has been proposed and has been put to practical use as a fixing device (JP-A-63-313182, JP-A-1-263).
Nos. 679, 2-15778, 4-44
Nos. 075-44083 and 4-204980-20
No. 4984).

This film heating type heating device has a heating element, and a film having one surface sliding with the heating element and the other surface moving together with the material to be heated. In this case, the unfixed toner image is permanently fixed to the surface of the recording material such as paper carrying the image in the image forming apparatus. It can be used as a fixing device that performs heat fixing processing as an image. In addition, it can be widely used as a device for heating a recording material carrying an image to improve the surface properties such as gloss, a device for assuming deposition, and a heating device for heating a sheet-shaped material to be heated.

[0008] Unlike a heating apparatus such as a heat roller method, such a film heating type heating apparatus can use a heating element having a low heat capacity or a thin film having a rapid temperature rise, so that the heating element can be heated in a short time. Since the temperature of the heating member rises, there is no need to conduct the heating of the heating member during standby, and even if the material to be heated is passed immediately, the heating member is kept at a predetermined temperature until the heating member reaches the heating nip. Temperature can be sufficiently increased, power saving and shortening of wait time (cook start property, on-demand) can be achieved, and temperature rise in the apparatus such as an image forming apparatus can be reduced. Have the advantage,
It is effective.

[0009] A ceramic heater is a heating element having a high heat-up rate and a low heat capacity used in a film heating type heating apparatus. This uses a ceramic material, such as alumina (Al ₂ O ₃ , aluminum oxide), having characteristics such as heat resistance, electrical insulation, good thermal conductivity, and low heat capacity, for the heating substrate,
A basic configuration is a configuration in which a heating element (resistance heating element) that generates heat by energization by, for example, pattern-printing and baking an electric resistance material paste such as silver palladium (Ag / Pd) on the substrate is used. In addition, the heating element, including the substrate, is quickly heated as a whole by the heat generated by energization of the heating element. When the power supply to the heating element is cut off, the temperature of the heating element rapidly decreases.

[0010] The heating element is provided with a temperature detecting element such as a thermistor, and energization of the heating element is controlled based on the electrical output (heating element temperature detection information) of the temperature detecting element, and a predetermined heating is performed. The temperature is controlled to the body temperature.

To energize the heating element provided on the heating element, the heating element substrate is provided with electrode portions (feeding electrode patterns) electrically connected to one end and the other end of the heating element, respectively. A pressure spring as an electrical contact is brought into contact with the unit, and a voltage is applied to the electrode unit from an external power supply unit (high-voltage circuit) via the pressure spring.

In addition, the electrical output from the temperature detecting element provided on the heating element to an external control system is supplied to the heating element substrate by:
Comprising an electrode portion electrically connected to the temperature detecting element,
A pressure spring as an electrical contact is brought into contact with this electrode part,
This is done via this pressure spring.

[0013]

A heating element is provided, as in the above-described ceramic heater, and an electrode section is provided on a heating element substrate which is heated by the heat generated by the heating element. In a heating element having a configuration in which a pressure spring as a contact is brought into contact, the temperature of the heating element substrate rises due to the heat generated by the heating element. The temperature of the contact portion also rises, and the temperature of the pressure spring rises.

If the temperature rise of the pressure spring is likely to exceed the temperature at which the spring constant of the pressure spring decreases (heat-resistant temperature of the pressure spring), the pressure spring with respect to the electrode portion of the heating element substrate is moved. The contact pressure decreases, and the pressure spring floats from the electrode portion of the heating substrate, causing poor conduction between the electrode portion and the pressure spring, or an electrical connection of the pressure spring to the electrode portion of the heating substrate. The contact becomes unstable, and a discharge phenomenon occurs in the unstable contact portion and the like, and damage due to burnt contact is likely to occur.

In particular, in the case of a heating body using a ceramic material such as aluminum nitride (AlN) or silicon carbide (SiC), which has higher thermal conductivity than alumina, as a heating body substrate, a substrate provided with an electrode portion is used. The heat transfer temperature of the portion is also increased to the same extent as that of the substrate portion on which the heating element is provided, and the temperature rise of the pressure spring is likely to exceed the heat resistant temperature of the pressure spring.

Accordingly, the present invention provides a heating element in which a heating element is provided, an electrode section is provided on a heating element substrate whose temperature is increased by the heat generated by the heating element, and a pressure spring as an electrical contact is brought into contact with the electrode section. A heating device having the heating element, an image forming apparatus including the heating device as an image heating and fixing means, even when using a substrate having excellent thermal conductivity such as aluminum nitride as a heating substrate, the heating substrate By preventing a decrease in the spring constant due to a temperature rise exceeding the heat resistance temperature of the pressure spring as an electrical contact that contacts the provided electrode part,
An object of the present invention is to improve the life and reliability of a heating element and a device by eliminating poor conduction between an electrode portion and a pressure spring and occurrence of burnt contact caused by poor conduction.

[0017]

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 heating element which is provided with a heating element, has an electrode section on a heating element substrate which is heated by the heat generated by the heating element, and contacts a pressure spring as an electrical contact with the electrode section. A heating element, wherein a heat radiating member is disposed at a portion corresponding to a contact portion between an electrode portion and a pressure spring.

(2) A heating element provided with a heating element, having an electrode portion on a heating substrate heated by the heat generated by the heating element, and contacting a pressure spring as an electrical contact with the electrode portion. A heating element characterized in that a portion from an electrode portion of the heating element substrate to an end of the heating element substrate is a heat radiating portion.

(3) A heating element provided with a heating element, having an electrode section on a heating element substrate which is heated by the heat generated by the heating element, and contacting a pressure spring as an electrical contact with the electrode section. A heating element characterized in that a portion from an electrode portion of the heating element substrate to an end of the heating element substrate is a heat radiation part, and a heat radiation member is arranged in the heat radiation part.

(4) The heating element according to any one of (1) to (3), wherein the heating element is a heating element that generates heat when energized, and the electrode portion is electrically connected to the heating element. The heating element according to the above.

(5) The heating element substrate is provided with a temperature detecting element, and the electrode portion is electrically connected to the temperature detecting element. The heating element according to the above.

(6) The heating body substrate is made of aluminum nitride (A
1N). The heating element according to any one of (1) to (5), wherein

(7) A heating element is provided, the heating element substrate, which is heated by the heat generated by the heating element, has an electrode portion, is fixedly supported by a heating member support, and has an electrode serving as an electrical contact. In a heating device for heating a material to be heated by a heating element brought into contact with a pressure spring, a heat radiating member is provided at a portion corresponding to a contact portion between an electrode portion and a pressure spring of a heating element support for fixedly supporting the heating element. A heating device characterized by being arranged.

(8) A heating element is provided. The heating element substrate, which is heated by the heat generated by the heating element, has an electrode portion, is fixed and supported by a heating member support, and has an electrode as an electrical contact. In a heating device for heating a material to be heated by a heating body brought into contact with a pressure spring, the heating device includes the pressure spring, and a connector for contacting / fixing and holding the pressure spring to an electrode portion, and a heat radiating member of the pressure spring. A heating device.

(9) A heating element is provided. The heating element substrate, which is heated by the heat generated by the heating element, has an electrode portion. The electrode portion is fixed and supported by a heating member support. A heating device for heating a material to be heated by a heating member brought into contact with a pressure spring, wherein a portion from an electrode portion of the heating substrate to an end of the heating substrate is used as a heat radiating portion.

(10) A heating element is provided, an electrode portion is provided on a heating substrate which is heated by the heat of the heating element, and is fixed and supported by a heating member support. In a heating device for heating a material to be heated by a heating element brought into contact with a pressure spring, a portion from an electrode portion of the heating element substrate to an end of the heating element substrate is used as a heat radiating portion, and a heat radiating member is arranged in this heat radiating portion. And a heating device.

(11) a contact portion between the electrode portion and the pressure spring;
Or (7) to (1) characterized by having air path means for air-cooling the heat radiating member portion or the heat radiating portion.
0) The heating device according to any one of the above.

(12) The heating element according to any one of (7) to (11), wherein the heating element is a heating element that generates heat when energized, and the electrode portion is electrically connected to the heating element. A heating device as described.

(13) The heating element substrate is provided with a temperature detecting element, and the electrode portion is electrically connected to the temperature detecting element. A heating device as described.

(14) The heating substrate is made of aluminum nitride (AlN).
The heating device according to any one of 3).

(15) A heating element is provided. The heating element substrate, which is heated by the heat generated by the heating element, has an electrode portion. The electrode portion is fixed and supported by the heating member support. A heating element contacted with a pressure spring, a film having one surface sliding with the heating element and the other surface moving in contact with the material to be heated, and In a heating device for heating a material to be heated by heat, a heat radiating member is arranged at a portion of a heating body support for fixedly supporting a heating body, the portion corresponding to a contact portion between an electrode portion and a pressure spring. apparatus.

(16) A heating element is provided. The heating element has an electrode portion on a heating substrate which is heated by the heat generated by the heating element. The electrode portion is fixed and supported by the heating member support. A heating element contacted with a pressure spring, a film having one surface sliding with the heating element and the other surface moving in contact with the material to be heated, and A heating device for heating a material to be heated by heat, wherein the connector includes the pressure spring, and a connector that contacts / fixes and holds the pressure spring to an electrode portion is a heat radiating member of the pressure spring. .

(17) A heating element is provided, the heating element substrate, which is heated by the heat generated by the heating element, has an electrode portion, is fixedly supported by a heating member support, and has an electrode as an electrical contact. A heating element contacted with a pressure spring, a film having one surface sliding with the heating element and the other surface moving in contact with the material to be heated, and A heating device for heating a material to be heated by heat, wherein a portion from an electrode portion of the heating body substrate to an end of the heating body substrate is used as a heat radiating portion.

(18) A heating element is provided. The heating element substrate, which is heated by the heat generated by the heating element, has an electrode portion, is fixed and supported by a heating member support, and has an electrode as an electrical contact. A heating element contacted with a pressure spring, a film having one surface sliding with the heating element and the other surface moving in contact with the material to be heated, and A heating device for heating a material to be heated by heat, wherein a portion from an electrode portion of a heating body substrate to an end portion of the heating body substrate is used as a heat dissipation portion, and a heat dissipation member is arranged in the heat dissipation portion.

(19) a contact portion between the electrode portion and the pressure spring;
Alternatively, the heating device according to any one of (15) to (18), further comprising an air path means for air-cooling the heat radiating member or the heat radiating portion.

(20) The heating element according to any one of (15) to (19), wherein the heating element is a heating element that generates heat when energized, and the electrode portion is electrically connected to the heating element. A heating device as described.

(21) Any one of (15) to (20), wherein a temperature detecting element is provided on the heating body substrate, and the electrode portion is electrically connected to the temperature detecting element.
The heating device according to any one of the above.

(22) The heating substrate is made of aluminum nitride (AlN).
The heating device according to any one of 1).

(23) A pressurizing member for forming a nip by pressing the heating body through the film is provided, and the material to be heated is nipped and conveyed between the film and the pressurizing member in the nip portion to interpose the film. The heating device according to any one of (15) to (22), wherein the material to be heated is heated by the heat from the heating body.

(24) The material to be heated is a recording material carrying an image, and the apparatus is an image heating device for heating the recording material. A heating device according to one of the preceding claims.

(25) The material to be heated is a recording material carrying an unfixed image, and the apparatus is an image heat fixing device for fixing the unfixed image to the recording material.
5) The heating device according to any one of (24) to (24).

(26) An image forming apparatus provided with an image forming means for forming an unfixed image on a recording material and an image heating and fixing means for fixing the unfixed image on the recording material.
The image heating and fixing unit may be a heating device provided with the heating element according to any one of (1) to (6), or the heating device according to any one of (7) to (25). An image forming apparatus, comprising:

(27) A contact portion between the electrode portion of the heating element and the pressure spring, a heat radiating member, or a heat radiating portion is disposed between the body frame and the exterior of the image forming apparatus. The image forming apparatus according to (26).

<Operation> That is, the pressure spring is provided with a means for positively radiating heat from a contact portion between the electrode portion provided on the heating element substrate and the pressure spring contacting the electrode portion. Is maintained at a temperature lower than the heat-resistant temperature of the pressure spring, so that a decrease in the spring constant can be prevented.

Therefore, even when a substrate having excellent thermal conductivity, such as aluminum nitride, is used as the heating substrate, it exceeds the heat resistance temperature of the pressure spring as an electrical contact that contacts the electrode portion provided on the heating substrate. It is possible to prevent a decrease in the spring constant due to a rise in temperature, to prevent poor conduction between the electrode portion and the pressure spring, and to prevent occurrence of contact burn due to poor conduction, thereby improving the life and reliability of the heating element and the device. .

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 (FIGS. 1 to 8) FIG. 1 is a schematic configuration diagram of an example of a film heating type heating apparatus according to the present invention, FIG. FIG. 3A is a front side model diagram and a block diagram of a power supply system of a partially cutaway portion of the heating element, and FIG. 3B is a back side model diagram.

The heating device of this embodiment is an image heating fixing device of a pressure roller drive type.

(1) Overall Schematic Configuration of Apparatus In FIGS. 1 and 2, reference numeral 10 denotes a general reference number of a heating apparatus, 1 denotes a horizontally long ceramic heater as a heating body, and 2 denotes an approximately semi-arc-shaped trough-shaped trough. Heater support (film guide, stay), 3 is a cylindrical heat-resistant film (fixing film),
Reference numeral 4 denotes an elastic pressure roller as a pressure member.

The heating member support 2 is made of a heat-resistant, electrically insulating, rigid material capable of withstanding high loads, for example, PPS (polyphenylene sulfide), PAI (polyamide imide), PI (polyimide), and PEEK (polyether ether ketone). ), Etc., and the heating element 1 is provided with a groove 2a provided along the longitudinal direction substantially at the center of the lower surface of the heating element support 2.
It is fitted and held inside.

The cylindrical film 3 is externally fitted to a heater support 2 including the heater 1 described above. The inner peripheral length of the cylindrical film 3 is larger than the outer peripheral length of the heater support 2 including the heater 1 by, for example, about 3 mm, and the peripheral length of the cylindrical film 3 is larger than that of the heater support 2. It has a loose fit.

The film 3 is used to increase heat transfer, reduce heat capacity, and improve quick start.
The film thickness is 100 μm or less, preferably 10 to 50
A heat-resistant single-layer film of PTFE, PFA, FEP, etc. of about μm, or a composite layer film of a base film of polyimide, polyamideimide, PEEK, PES, PPS, etc. coated with PTFE, PFA, FEP, etc. Can be used. In this example, a film in which the outer peripheral surface of a polyimide film was coated with PTFE was used.

The elastic pressure roller 4 comprises a metal core 4a and a roller layer 4b of an elastic and heat-resistant material having good releasability, such as silicon rubber, provided concentrically and integrally with the metal core.
Are rotatably supported via bearings between front and rear chassis side plates of the heating device.

Then, the heating element 1 is held on the lower surface side, and the heating element support 2 with the cylindrical film 3 fitted thereon is placed above the pressure roller 4, and the heating element 1 is opposed to the upper surface of the pressure roller 4. The heating body support 2 is kept pressed against the upper surface of the pressure roller 4 by a pressing means (not shown) with a predetermined pressing force. As a result, a fixing nip portion N having a predetermined width is formed between the lower surface of the heating element 1 and the upper surface of the pressure roller 4 with the film 3 interposed therebetween.

The pressing roller 4 is driven to rotate in a counterclockwise direction indicated by an arrow by a driving means M. The cylindrical film 3 is pressed by the frictional contact between the outer surface of the roller 4 and the outer surface of the film 3 at the nip N by the rotational drive of the pressure roller 4.
And the film 3 substantially corresponds to the rotational peripheral speed of the pressure roller 4 in the clockwise direction a as indicated by the arrow while the inner surface of the film 3 slides in close contact with the lower surface of the heating element 1 at the nip portion N. The heating body support 2 is rotated around the periphery of the heating body support 2 at a peripheral speed (a pressure roller driving system).

The heating member support 2 also serves as a film guide for holding the heating member 1 and improving the transport stability of the film 3 during rotation.

In order to reduce the sliding resistance between the inner surface of the film 3 and the surface of the heater 1, a small amount of lubricant such as heat-resistant grease can be interposed between the two.

Thus, the pressure roller 4 is driven to rotate,
Along with this, the cylindrical film 3 rotates around the outer periphery of the heater support 2, and the heater 1 is energized, and the heat of the heater 1 raises the temperature of the nip N to a predetermined temperature and regulates the temperature. A recording material P such as paper as a heated material carrying the unfixed toner image t is introduced into the nip portion N, and the toner image bearing surface side of the recording material P is brought into close contact with the outer surface of the film 3 in the nip portion N. The nip N is conveyed together with the film 3.

In this nipping and conveying process, the heat of the heating element 1 is applied to the recording material P via the film 3, and the unfixed toner image t on the recording material P is heated and pressed.

When the recording material P passes through the nip portion N, it is conveyed with a curvature separated from the outer surface of the film 3.

(2) Structure of the Heating Element 1 (Mainly FIG. 3) The ceramic heater 1 as the heating element has a low heat capacity and a high temperature as a whole. A resistance heating element 12 provided on the front side of the substrate 11 along the length of the substrate, first and second electrode patterns 13 and 14 for supplying power to the resistance heating element 12, and conductive path (conductor) patterns 15 16. Third for temperature sensing element
And the fourth electrode patterns 18 and 19, the surface protection layer 17 on the substrate front side, the temperature detecting element 24 disposed on the substrate rear side, the temperature detecting element 24 and the third and fourth electrode patterns 18.
・ Through holes 20 and 21 electrically connected to 19
And conductive path patterns 22 and 23.

The heating element 1 is held in the groove 2 a on the lower surface of the heating element support 2 by exposing the surface of the substrate on which the resistance heating element 12 is formed to be exposed downward.

The heating body substrate 11 is a horizontally long and thin one having a longitudinal direction (film width direction) perpendicular to the recording material conveying direction a in the nip portion N, and is an alumina (Al ₂ O ₃ ) substrate. And a ceramic substrate such as an aluminum nitride (AlN) substrate and a silicon carbide (SiC) substrate. In the present embodiment, a high thermal conductivity, a low coefficient of thermal expansion, a high strength, and a light weight of 270 mm in length, 7 mm in width,
An AlN substrate having a thickness of 1 mm was used.

Here, various characteristics of the AlN substrate will be described below in comparison with the alumina substrate.

AlN Alumina Heating rate (° C./sec) 600 200 or less Thermal conductivity (W / cm ² ) 500 30 Thermal expansion coefficient (× 10 ⁻⁷ / ° C) 39 73 Flexural strength (Kg / mm ² ) 35 32 Density (g / cm ³ ) 3.32 3.99 The resistance heating element 12 is made of an electric resistance material paste such as Ag / Pb (silver palladium) having a thickness of 10 to 20 μm and a width of 0.8 to 20 μm.
It is formed by applying a thin strip pattern of 3 mm along the length of the substrate by screen printing and firing.

The first and second electrode patterns 13 and 14 are arranged side by side at one longitudinal end of the substrate surface, and the first electrode pattern 13 and one end of the resistance heating element 12 are connected to the conductive path pattern 1.
5, the second electrode pattern 16 and the other end of the resistance heating element 12 are electrically connected by a conductive path pattern 116 formed substantially parallel to the resistance heating element 12.

Thus, the first electrode pattern 13 → the conductive path pattern 15 → the resistance heating element 12 → the conductive path pattern 1
6 → Series electric circuit of second electrode pattern 14 (AC line)
Is configured.

Further, the third and fourth electrode patterns 18 and 1
Reference numeral 9 denotes two conductive path patterns 2 which are juxtaposed at one longitudinal end portion of the substrate surface and are formed on the rear surface side of the substrate through through holes 20 and 21 so as to reach a substantially central portion of the substrate longitudinal direction.
Conduction with 2.23. A thermistor 24 as a temperature detecting element is provided between the end portions of the two conductive path patterns 22 and 23.

Thus, the third electrode pattern 18 → the through hole 20 → the conductive path pattern 22 → thermistor 2
4 → conductive path pattern 23 → through hole 21 → fourth electrode pattern 19 constitutes a series electric path (DC line).

In this embodiment, the thermistor 24 is formed by mixing an alloy of cobalt, manganese, nickel, ruthenium or the like, an oxide, a particle of ceramic such as platinum or barium titanate with a glass paste material, and forming the mixture on the back surface of the substrate. It was a thin layer type formed by screen printing. It can also be a chip thermistor.

The first to fourth electrode patterns 13.1
4.18.19, conductive path pattern 15.16.22.2.
No. 3 is formed by applying a silver (Ag) paste at a predetermined position on the front surface side and the rear surface side of the substrate by screen printing in a predetermined pattern, and firing it.

The surface protective layer 17 is a coat layer made of glass, fluororesin, or the like. As shown in FIG. 3A, the first to fourth electrode patterns 13, 14, 18, and 19 are formed on the substrate surface side. Except coated.

(3) Power Supply System for Heating Body 1 An AC line (for power supply) is provided on one end side of the heating body having the first and second electrode patterns 13 and 14 of the AC line of the heating body 1. When the connector 31 is fitted, two pressing springs 32 as electrical contacts in the connector 31 are connected.
32 are in pressure contact with the first and second electrode patterns 13 and 14 respectively, and the AC line of the heating element 1 and the commercial power supply 34.
A power supply circuit including the triac 35 and the like is connected. 33 is a power supply wire connected to the pressure spring 32 as an electrical contact. First and second electrode patterns 13.1
By supplying power between the four, the resistance heating element 12 generates heat, and the temperature of the heating element 1 rapidly rises as a whole.

The third and fourth DC lines of the heating element 1
A DC line (signal extraction) connector 36 is fitted to the other end of the heating body having the electrode patterns 18 and
The two pressure springs 37 are in pressure contact with the third and fourth electrode patterns 18 and 19, respectively, so that the DC line of the heater 1 and the A / D converter 39 of the control system are connected. 3
Reference numeral 8 denotes a lead wire connected to a pressure spring 37 as an electrical contact.

A thermistor voltage as temperature information of the heating element 1 is input from a DC line to an A / D converter 39 via a connector 36 and is converted into digital data by a CPU 4.
It is taken into 0.

The CPU 40 controls the triac 35 based on the input digital data so as to control the temperature of the heater to a predetermined constant temperature. That is, the power supply to the AC line is controlled.

More specifically, the temperature of the heating element 1 is controlled by A / D conversion of the output of the temperature detecting element 24 such as a thermistor provided in the paper passing area of the recording material by the A / D converter 39. A is taken in by the CPU 40, and based on the information, the triac 35 is used to energize the resistance heating element 12 of the heating element 1 A
The control is performed by controlling the power supplied to the resistance heating element 12 by controlling the phase and the wave number of the C voltage.

The temperature of the heating element 1 is controlled by controlling the voltage or current applied to the resistance heating element 12 or by controlling the energizing time. The method of controlling the power-on time is as follows:
There are zero-cross wave number control for controlling energization and non-energization, and phase control for controlling a phase angle to be energized for each half-wave of the power supply waveform.

As shown in FIG. 4 (a), both ends of the longitudinal direction of the heater support 2 which has a substantially semicircular trough-shaped cross section and also serves as a film guide correspond to the substantially central portions of the lower surface, respectively. First and second extended arms 2 projecting outwardly in position
b and 2c, and the heating element fitting groove 2a provided along the longitudinal direction substantially at the center of the lower surface of the heating element support 2 is provided in the first and second extension arms 2b and 2c, respectively. It is straddled and provided.

In a state where the heating element 1 is fitted and received in the groove 2a, one end of the heating element having the first and second electrode patterns 13 and 14 of the AC line of the heating element 1 is a first extension arm. 2b, the third and fourth DC lines
The other end of the heating element having the electrode patterns 18 and 19 is located in the groove of the second extended arm 2c.

The connector 31 for the AC line and the connector 36 for the DC line are made in the same manner, and include a connector outer shell 31a (36a) and two pressurizing springs 32, 32 (37) fixed and held therein.・ It consists of 37). FIG. 4B is a perspective view of the pressure spring.

The connector outer shell 31a (36a) is a molded product of a heat-resistant and insulating resin such as nylon, and has a fitting opening for vertically holding the above-mentioned extended arm of the heater support. The pressure spring is a press-punched bent formed body of a metal plate. The pressurizing spring and the power supply wire 33 or the lead wire 38 are electrically connected by crimping.

When the AC line connector 31 is fitted to the first extension arm 2b of the heater support 2 in a predetermined manner, the two pressure springs as electrical contacts in the connector 31 are provided. 32 and 32 respectively come into pressure contact with the first and second electrode patterns 13 and 14 of the AC line of the heating element 1.

The DC line connector 36 is fitted to the second extension arm 2c in a predetermined manner, so that the connector 3
6, two pressure springs 37, 37 serving as electrical contacts, are in pressure contact with the third and fourth electrode patterns 18, 19 of the DC line of the heating element 1, respectively. The parts are in contact with a small area. The connectors 31 and 36 fitted to the extension arms 2b and 2c of the heater support 2 also have a role of fixing and disposing the heater 1 on the heater support 2.

(4) Heat Dissipation Configuration By the way, in the heating element 1, since the temperature of the heating element substrate 11 is increased by the heat generated by the resistance heating element 12, the electrode pattern 13
· Heat is also transferred to the substrate portion provided with 14, 18, 19, and the electrode patterns 13, 14, 18, 19, and the pressing springs 32, 3
The temperature of the contact portions of 2, 37 also rises, and the temperature of the pressure spring rises. If the temperature rise of the pressure spring seems to exceed the temperature at which the spring constant of the pressure spring decreases (heat-resistant temperature of the pressure spring), the electrode pattern 13.
4, 18, 19 pressing springs 32, 32, 37.3
7, the pressure spring floats from the electrode pattern of the heating substrate, causing poor conduction between the electrode pattern and the pressure spring, or the pressure spring against the electrode pattern of the heating substrate. The electrical contact becomes unstable,
In the power supply connector 31, a discharge phenomenon occurs at an unstable contact portion or the like, and damage due to burnt contact is likely to occur.

In particular, in the case of a heating body using a ceramic material such as aluminum nitride (AlN) or silicon carbide (SiC), which has higher thermal conductivity than alumina, as the heating body substrate, the substrate provided with the electrode portion is used. The heat transfer temperature of the portion is also increased to the same extent as that of the substrate portion on which the heating element is provided, and the temperature rise of the pressure spring is likely to exceed the heat resistant temperature of the pressure spring.

In other words, conventionally, a relatively inexpensive ceramic substrate made of alumina or the like having heat resistance, electric insulation, and low heat capacity has been used as the heater substrate 11 of the heater 1. However, due to the current trend, the image forming apparatus such as a copying machine or a printer is required to have a higher speed and a shorter wait time (quick start), and the heater substrate 11 is replaced with a ceramic substrate such as alumina. There has been a need for a material having excellent thermal conductivity that can supply heat to the whole or the pressure roller.

Further, as a problem when using a ceramic substrate made of alumina or the like, there is a problem in that the temperature of the non-sheet passing portion rises. This is when passing small-size paper, and in the non-paper passing area,
Since the amount of heat taken by the recording material P is reduced as compared with the sheet passing area, a non-sheet passing portion temperature rise occurs in which the temperature of the non-sheet passing area of the heating body increases. As a result, when the temperature rise in the non-sheet passing portion is extremely large, the temperature distribution in the longitudinal direction of the heating body becomes non-uniform, causing image defects, thermal deterioration of other members such as the pressure roller, and further, the heating body. Problems such as breakage will occur.

Therefore, aluminum nitride (AlN), which is 17 times better in thermal conductivity than a ceramic substrate such as alumina and has a low coefficient of thermal expansion, high strength, and light weight, may be used as a material for a heating substrate instead of alumina. It is becoming. Also in this embodiment, the heating body substrate 11 is made of Al
An N substrate is used.

In the heating apparatus of the film heating system using the heating element 1 having AlN as the heating element substrate, the AlN substrate 11 has excellent thermal conductivity, and therefore, compared to the film heating apparatus using a ceramic substrate such as alumina. It is possible to shorten the wait time, and even when small-size paper is passed, the excellent thermal conductivity reduces unevenness in the temperature in the longitudinal direction of the heating body and reduces the temperature rise in the non-paper passing area. Is possible.

On the other hand, when the heating element 1 and the heating element support 2 are not adhered, the connectors 31 and 36 are fixed to the extension arms 2b and 2c of the heating element support, and therefore, during normal printing. For example, when the recording material P enters the nip N, the heating element 1 stops at a predetermined position in the groove 2a of the heating element support 2 due to the resistance applied to the heating element 1 via the fixing film when the recording material P enters the nip section N. When the heater 1 is slightly moved due to being unable to move, or when the heater 1 is adhered in the groove 2a of the heater support 2, the backlash between the connectors 31 and 36 and the heater support 2 may be caused. When the connectors 31 and 36 move minutely, the electrode patterns 13 and 14 and 18 are moved.
The minute contact portion between the pressure spring 19 and the pressure springs 32, 32, 37, 37 is scraped by the contact portions of the pressure springs. Then, the shaved constituent material of the electrode pattern, for example, Ag, is pushed beside the minute contact portion, and as a result, a concave portion of the electrode pattern is formed in the minute contact portion.

In the heating element using the alumina ceramic substrate, the thermal conductivity is about 1/17 of that of the AlN substrate.
Before the heat of the resistance heating element 12 generated by the energization is transferred and heated, the heating element 1 enters the air or the heating element support 2.
Since the heat was dissipated, the temperature of the electrode pattern portion did not become so high. In such a case, even if the concave portion of the electrode pattern is formed in the minute contact portion, the spring constant of the pressing spring in contact with the electrode pattern does not change, so that the conduction between the electrode pattern and the pressing spring is ensured.

However, by using an AlN substrate having excellent thermal conductivity for the heating element substrate 11, the heat of the resistance heating element 12 generated by energization is immediately reduced to the electrode pattern 13.
Heat is transferred to the minute contact portions between the pressure springs 14, 18, 19 and the pressure springs 32, 32, 37, 37, and the temperature rises. As a result, the temperature of the pressure springs 32, 32, 37, 37 rises above the heat-resistant temperature of the pressure springs, the spring constant of the pressure springs decreases, and the pressure springs Floating from the pattern, it becomes impossible to conduct. A
On the C-line connector 31 side, when an AC voltage is applied thereto, a discharge phenomenon occurs in a certain place in the concave portion of the electrode pattern, and damage due to burnt contact occurs.

Therefore, in the present embodiment, the first and second electrode patterns 13 and 14 of the AC line of the heating element 1 and the minute contact portions of the pressure springs 32 and 32 on the AC line connector 31 side are used. The first extension arm 2b of the heating element support 2 is made of a material having good heat dissipation such as aluminum, and is used as the heat dissipation member 41.

That is, from the resistance heating element 12 to the AlN substrate 11
As a result, the heat conducted to the first and second electrode patterns 13 and 14 is dissipated into the air by the heat dissipating member 41 serving as the first extended arm 2b in contact with the AlN substrate portion, and the first In addition, the configuration of lowering the temperature of the second electrode patterns 13 and 14 prevents an excessive rise in temperature of the minute contact portion and the pressure springs 32.

Actually, 8 sheets / minute (process speed of about 5
0 mm / sec) with a fixing heating temperature of 18
The temperature is set to 0 ° C., 100 sheets are printed, and the minute contact temperature between the first and second electrode patterns 13 and 14 and the pressing springs 32 and 32 in a state of thermal equilibrium is measured, and continuous printing is repeated. A durability test was performed.

COMPARATIVE EXAMPLE 1 First and second cases in which the heating element substrate 11 was an AlN substrate and the first extension arm 2b of the heating element support 2 was not used as a heat radiating member. The minute contact temperature between the second electrode patterns 13 and 14 and the pressure springs 32 was 165 ° C.

Comparative Example 2 First and second cases in which the heating element substrate 11 was an alumina substrate and the first extension arm 2b of the heating element support 2 was not used as a heat radiating member. The minute contact temperature between the second electrode patterns 13 and 14 and the pressure springs 32 was 145 ° C.

From this, it can be seen that, in the case of the heating element 1 of Comparative Example 1 in which the heating element substrate 11 is an AlN substrate, the minute contact temperature becomes high because the thermal conductivity of the AlN substrate is good. Then, the minute contact temperature continues to rise, and becomes a temperature close to the fixing heating temperature 180 ° C. controlled by the thermistor 14. The heat resistance temperature at which the spring constant of the pressure spring 32 does not change is 160 ° C., and due to a durability test in which continuous printing is repeated, burning of the contact occurs after 20,000 sheets, and the power supply to the resistance heating element 12 of the heating element 1 is stopped. I have.

This embodiment: Even when the heating element 1 in which the heating element substrate 11 is an alumina substrate is used, as in this example,
When the first extended arm portion 2b of the heater support 2 is formed of the heat dissipating member 41, the heat dissipating effect of the heat dissipating member 41 allows the first and second electrode patterns 13 and 14 and the pressure springs 32 and 3.3 to be used.
The temperature of the minute contact point with No. 2 becomes 156 ° C., which can be lower than the heat-resistant temperature 160 ° C. of the pressing spring. No abnormalities occurred.

Further, when the heat radiating member 41 is provided with irregularities or fins 42 as shown in FIG. 6 so as to increase the heat radiating efficiency of the heat radiating member 41, the first and second electrode patterns 13 and 14 are provided. The minute contact temperature between the pressure springs 32 and 32 became 152 ° C., and the margin for burnt contact was able to be increased. Needless to say, even in the durability test in which continuous printing is repeated, even after the end of 50,000 sheets, no abnormality of the heating device due to burnt contact occurred.

Further, in the heat radiation structure shown in FIGS. 5 and 6, as shown in FIG.
A counterbore (step portion) 2d is provided on the bottom surface of
By providing a non-contact portion between the heating element support 2 and the heating element support 2, the amount of heat of the resistance heating element 12 of the heating element 1 taken away by the heating element support 2 is reduced, and the heat generation of the resistance heating element 12 is reduced. It is possible to lower the temperature of the minute contact portion between the electrode pattern and the pressure spring, which is more preferable.

5 and 6, since the heating element 1 is pressed against the heating element support 2 by the opposing pressure roller 4, the boundary between the heating element support 2 and the heat dissipating member 41 is formed. In the case where there is a concern that a mechanical stress may occur due to a step or gap between the two, as shown in FIG. 8, the first extended arm portion 2b having a reduced thickness is connected to the heater support. 2 and a first extended arm 2
It is also possible to adopt a configuration in which the heat radiation member 41 is provided outside b, and in this case also, the effect of lowering the temperature of the minute contact portion between the electrode pattern and the pressure spring is the same.

As described above, with the above-described heat radiating means configuration, by using AlN having excellent thermal conductivity as the substrate 11 of the heating element, the heat of the resistance heating element generated by energization is transferred to the electrode patterns 13 and 14. As a result, the temperature of the pressure springs 32 as electrical contacts to the electrode pattern excessively increases, and the spring constant of the pressure springs decreases,
As a result, it was possible to prevent the problem that the electrode pattern was damaged due to burnt contact at the minute contact portion between the electrode pattern and the pressure spring, and a good image could be obtained.

<Embodiment 2> (FIG. 9) In this embodiment, the AC line connector 31 itself has a heat radiation function. That is, in this example, the connector outer shell 3
1a was made of a material having good heat dissipation properties such as aluminum, and was used as a heat dissipation member. In this case, the pressurizing springs 32 as electrical contacts are electrically insulated from the connector outer shell by thin insulating members 31b, 31b of heat-resistant insulating resin or the like, and are contact-fixed in the connector outer shell 31a. Arranged.

This connector 31 is connected to the first
The first and second electrode patterns 1 on the AlN substrate 11 of the heating element 1
Even if the temperature of 3.14 rises, the heat transmitted to the pressure springs 32 is transmitted to the connector outer shell 31a having heat radiation, and is radiated into the air by the connector outer shell 31a. This prevents the pressure spring 32 from rising excessively and the minute contact portions of the electrode patterns 13 and 14 that are in contact with the pressure spring from being excessively raised, and thus prevents the spring constant of the pressure spring 32 from decreasing. Therefore, the contact burn does not occur.

Also in this embodiment, a measurement of a minute contact temperature and a durability test in which continuous printing was repeated were performed in the same manner as in the first embodiment. The first and second electrode patterns 13 and 14 and the pressure spring 3
The temperature of the minute contact with 2.32.32 ° C. becomes 157 ° C., which can be lower than the heat-resistant temperature of the pressure spring of 160 ° C., and is also 50,000 in the durability test in which continuous printing is repeated.
Even at the end of the sheet, no abnormality of the heating device due to burnt contact occurred.

An insulating member 31b which electrically insulates the heat radiating connector outer shell 31a from the internal pressure springs 32.
It is more preferable to select and use a material having excellent thermal conductivity for 31b. When the heat radiating connector outer shell 31a is made of a material having an insulating property and excellent heat conductivity, the heat radiating connector outer shell 31a and the pressing springs 32 may be in direct contact.

In FIG. 9, since the heat dissipating connector 31 also plays a role of fixing the heater 1 to the heater support 2, the heat dissipating connector comes into contact with the heater support,
The first and second electrode patterns 13 and 14 and the pressure spring 32
There is also an effect of dissipating the heat of the heater portion and the heater support portion corresponding to the minute contact portion with the heater 32.

<Embodiment 3> (FIG. 10) In this embodiment, the AlN used as the substrate 11 of the heating element 1 was used.
Focusing on the good thermal conductivity of the substrate, the AlN substrate 1
By using the structure 1 itself as a heat radiating member, excessive heating of the minute contact portion between the electrode patterns 13 and 14 of the heating element and the pressure springs 32 and 32 is prevented.

That is, in the present embodiment, the AlN substrate 11 of the heating element 1 has a length of 300 mm, which is 30 mm longer than the substrate used in the first and second embodiments, as shown in FIG. First and second electrode patterns 13 and 14
A heating body 1 having a substrate extension 11a having a length of about 30 mm is provided before the substrate portion having the substrate extension, and the substrate extension 11a is connected to the first extension arm 2
The heating element 1 is assembled to the heating element support 2 in such a manner that the heating element 1 protrudes outward from the end of b as a heat radiation part.

First and second heating elements 1 on AlN substrate 11
The heat transfer to the electrode patterns 13 and 14 is dissipated into the air from the heat dissipating portion 11 which is an extension of the substrate. This prevents the pressure spring 32 from rising excessively and the minute contact portions of the electrode patterns 13 and 14 that are in contact with the pressure spring from being excessively raised, and thus prevents the spring constant of the pressure spring 32 from decreasing. Therefore, the contact burn does not occur.

Also in the present embodiment, a measurement of a minute contact temperature and a durability test in which continuous printing is repeated were performed in the same manner as in the first embodiment. Due to the heat dissipating effect of the heat dissipating portion 11 which is an extended portion of the substrate, the minute contact temperature between the first and second electrode patterns 13 and 14 and the pressure springs 32 becomes 158 ° C. In the endurance test in which continuous printing was repeatedly performed, even when 50,000 sheets were completed, no abnormality in the heating device due to burning of the contacts occurred.

Further, the substrate extension portion 1 which is the above-mentioned heat radiation portion
By further contacting and disposing a substrate heat radiation member 44 of aluminum or the like as shown in FIG.
The first and second electrode patterns 13 and 14 and the pressure spring 32
The temperature of the minute contact with 32 becomes 154 ° C., and the temperature of the minute contact portion can be further reduced, and the margin for burning of the contact can be increased, which is more preferable.

In the case of the configuration shown in FIGS. 10A and 10B, the method of fixing and holding the heater 1 with respect to the heater support 2 in the longitudinal direction is as follows.
In the case of non-adhesion, the heater and the heating element support 2 are adhered by an adhesive, as shown in FIG. 10 (c) and (d),
It is preferable to provide a concave portion and a convex portion, or a notch and a projection, which are engaged with each other on the N substrate 11 side and the heating element support 2 side.

<Embodiment 4> (FIGS. 11 to 13) In the present embodiment, the first and second electrode patterns 1
Air passages are provided by air passage means in the image forming apparatus at portions corresponding to the minute contact portions of the pressure springs 3 and 14 and the temperature of the minute contact portions is reduced by air-cooling. The purpose of the present invention is to prevent the spring constant from decreasing due to an excessive rise in the temperature of the pressure spring, thereby preventing contact burn.

That is, as shown in FIG. 11 (a), the first portion of the heater support 2 to which the AC line connector 31 is fitted is attached.
(At least the first and second electrode patterns 13 and 14 of the heating element 1 and the pressing spring 32.
32 minute contact portion), the duct 5 serving as an air passage means
In order to take in the air outside the image forming apparatus or exhaust the air inside the image forming apparatus according to 1, air paths are provided to cool the ambient temperature around the connector 31 to lower the temperature of the minute contact points, The purpose of the present invention is to prevent the spring constant from decreasing due to an excessive rise in the temperature of the pressure spring, thereby preventing contact burn.

Also in this embodiment, a measurement of a minute contact temperature and a durability test in which continuous printing is repeated were performed in the same manner as in the first embodiment. With the above-mentioned heat dissipation effect by air cooling,
, Second electrode patterns 13, 14 and pressure springs 32, 32
The contact temperature of the contact is 159 ° C, which can be lower than the heat-resistant temperature of the pressure spring of 160 ° C. Did not occur.

Further, the above-mentioned duct 51 is connected to FIG.
As shown in the drawing, a duct with a fan 52 is used to suck air outside the image forming apparatus or exhaust air inside the image forming apparatus, and an air path is provided to lower the ambient temperature around the connector 31 by air cooling. In this case, the minute contact temperature between the first and second electrode patterns 13 and 14 and the pressure springs 32 and 32 was 155 ° C., and the margin for burning of the contact could be increased. Further, in the durability test in which continuous printing was repeated, no abnormality of the heating device due to burnt contact occurred even at the end of 50,000 sheets.

Further, as shown in FIG. 12, the duct portion of the duct 51 with a fan, which is an air passage means, is extended to fit the power supply connector 31 of the heater support 2 into the duct 51. 1 is configured to include a portion corresponding to the extension arm portion 2b and to suck air outside the image forming apparatus or exhaust air inside the image forming apparatus. Is cooled by air, the first and second electrode patterns 13.
The minute contact temperature between 14 and the pressure springs 32 is 152 ° C.
As a result, the margin for burnt contact was further improved.

In the case of the configuration shown in FIG. 12, compared with the configuration shown in FIGS. 11A and 11B, the minuteness of the first and second electrode patterns 13 and 14 and the pressure springs 32 and 32 is smaller. Only the contact portions can be air-cooled, and the temperature of the minute contact portions can be reduced, and at the same time, the temperature of the film 3 for heating and fixing the unfixed image is prevented, and good fixability is secured. With the advantages that can be.

As shown in FIG. 13, between the main body frame 100 and the exterior 101 of the image forming apparatus, the heating element support 2 is provided.
First extension arm 2b fitted with the power supply connector 31
(At least the first and second electrode patterns 13 and 14 of the heating element 1 and the minute contact portions of the pressure springs 32 and 32), so that the air passage means In the case where the air temperature is reduced by air cooling around the connector 31 by providing an air path, there is no need to newly arrange a duct, and the minute contact portion can be cooled at low cost.

As described above, according to the structure of the heat radiating means of the first to fourth embodiments, AlN having excellent thermal conductivity is applied to the substrate 1 of the heating body.
By using as 1, the heat of the resistance heating element, which is generated by energization, is transmitted to the electrode patterns 13 and 14, and the pressure springs 32.3 as electrical contacts to the electrode patterns.
2 is excessively heated, the spring constant of the pressure spring is reduced, and as a result, the electrode pattern is damaged at the minute contact point between the electrode pattern and the pressure spring due to burnt contact of the electrode pattern. And a good image could be obtained.

The structure of the heat radiating means of the first to fourth embodiments may be arbitrarily combined.

Further, the structure of the heat radiating means of the first to fourth embodiments is similar to that of the first and second electrode patterns 13 on the AC line side of the heater 1.
14 and a pressure spring 32 on the AC line connector 31 side
In the first embodiment, the minute contact portion between the third and fourth electrode patterns 18 and 19 on the DC line side and the pressurizing springs 37 and 37 on the DC line connector 36 side are described. Needless to say, it is possible to adopt the same structure of the heat radiating means as in the case of (1) to (4). That is, the spring constant of the DC pressure springs 37 is also reduced due to an excessive temperature rise in the minute contact portions between the third and fourth electrode patterns 18 and 19 on the DC line side and the pressure springs 37. In other words, the DC pressure springs 37 are connected to the electrode patterns 18 on the AlN substrate 11.
The occurrence of a contact failure trouble that floats from the terminal 19 and makes it impossible to conduct can be prevented by adopting the structure of the heat radiating means.

<Embodiment 5> (FIG. 14) FIGS. 14A, 14B and 14C show other examples of the configuration of the heating apparatus 10 of the film heating type.

In the case of (a), an endless belt-like heat-resistant film 3 is suspended and stretched between a heating element (ceramic heater) 1, a driving roller 5, and a driven roller (tension roller) 6. The film 3 is configured to be rotationally driven by a driving roller 5. M is a driving unit of the driving roller 5. The pressure roller 4 is a film 3
It is driven and rotated with the rotational movement of.

(B) shows an endless belt-like heat-resistant film 3 between a heating member 1 and a driving roller 5.
Are suspended and driven to rotate by the drive roller 5. The pressure roller 4 rotates following the rotation of the film 3.

In the case of (c), a long rolled end film is used as the heat-resistant film 3, and the heat-resistant film 3 is passed through the heating element 1 from the pay-out shaft 7 side to the take-up shaft 8 side to a predetermined length. It is configured to run at a speed. M is a driving means of the winding shaft 8.

Embodiment 6 (FIG. 15) FIG. 15 is a schematic configuration diagram of an example of an image forming apparatus including, for example, the heating device 10 of Embodiment 1 as an image heating and fixing device.

The image forming apparatus of this embodiment is a laser beam printer using a transfer type electrophotographic process.

Reference numeral 61 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) as an image carrier, which is driven to rotate at a predetermined peripheral speed (process speed) in a clockwise direction indicated by an arrow.

The photosensitive drum 61 rotates during the rotation process.
Predetermined polarity / potential V _D (dark portion potential) by the secondary charger 62
And receives the laser beam scanning exposure L corresponding to the target image information by the laser scanner 63 on the charged surface. Thereby, the rotating photosensitive drum 6
An electrostatic latent image corresponding to the target image information is formed on one surface.

The laser scanner 63 outputs a laser beam whose intensity is modulated in accordance with a target image information signal (a time-series electric digital pixel signal) sent from an external device such as a host computer (not shown). The uniformly charged surface of the rotating photosensitive drum 61 is subjected to scanning exposure (raster scanning) L. The intensity of the laser beam and the diameter of the irradiation spot are appropriately set according to the resolution of the printer and the desired image density.

The portion irradiated with the laser beam on the uniformly charged surface of the rotating photosensitive drum 61 is attenuated to a bright portion potential V _L.
It becomes, otherwise parts the formation of an electrostatic latent image is formed by being held in the dark potential V _D which has been charged by the primary charger 62.

The electrostatic latent images formed on the surface of the rotating photosensitive drum 61 are sequentially developed by the developing device 64. The toner t in the developing device 64 is a developing sleeve 64 which is a toner supply rotating body.
a and the developing blade 64b control the thickness and tribo of the toner layer to form a uniform toner layer on the developing sleeve 64a. The developing blade 64b is usually made of metal or resin, and the resin blade is in contact with the developing sleeve 64a with an appropriate contact pressure. The toner layer formed on the developing sleeve 64a faces the photosensitive drum 61 with the rotation of the developing sleeve 64a itself, and the voltage _Vdc applied to the developing sleeve 64a.
And the electric field formed by the surface potential of the photosensitive drum 61 selectively visualizes only the bright portion potential _VL (reversal development).

The toner image formed on the surface of the rotating photosensitive drum 61 is fed at a predetermined control timing to the transfer portion, which is a press-contact nip portion between the photosensitive drum 61 and the transfer roller 65. Recording material (transfer material) P
Are sequentially transferred.

Reference numeral 67 denotes a paper feed cassette mounted at a lower portion in the printer, in which recording materials P are loaded and stored. The recording material P in the paper cassette 67 is fed by a paper feed roller 68.
The sheet is separated and fed by the separating claw member 69 and is fed to the transfer portion along the sheet path 70 at a predetermined control timing.

The recording material P to which the toner image has been transferred at the transfer portion is sequentially separated from the surface of the rotating photosensitive drum 61, and
The toner image is introduced into the fixing device 10 as an image heating device, and is subjected to a toner image fixing process (permanent fixed image formation by heating and pressing).
The sheet is sent to a sheet discharge tray 73 via a sheet path 71 and a sheet discharge roller 72.

On the other hand, the rotary photosensitive drum 6 after the recording material is separated
One surface is cleaned by the cleaning device 66 by removing the adhered residue such as untransferred toner, and is repeatedly provided for image formation.

<Others> a) The AC line configuration and the DC line configuration of the heating element 1 are not limited to the embodiment.

B) The substrate 11 of the ceramic heater as the heating element is not limited to aluminum nitride, but may be made of aluminum oxide (alumina), silicon carbide, or other ceramics.

C) As a means for protecting the heating element 1 from overheating, a safety element, for example, a temperature fuse or a thermoswitch is interposed in series with the power supply line to the AC line of the heating element 1 and brought into contact with or close to the heating element. May be arranged.

D) The surface of the heating element substrate 11 opposite to the surface on which the resistance heating elements 12 are formed may be used as a sliding surface with the film.

E) The pressing member need not be a roller.
For example, it can be a belt member.

F) The material to be heated P may be conveyed on the basis of one-sided conveyance or on the basis of central conveyance.

G) In the present invention, the heating device is not limited to the heating and fixing device of the embodiment, but may be an image heating device for heating a recording material carrying an image to improve the surface properties such as gloss.
Means and devices for heating the material to be heated, such as an image heating device to be assumed, a heating and drying device for the material to be heated, and a heating laminating device, are widely included.

H) The heating device is not limited to a film heating type heating device.

[0149]

As described above, according to the present invention,
A heating element provided with a heating element, having an electrode section on a heating element substrate which is heated by the heat generated by the heating element, and a pressure spring serving as an electrical contact with the electrode section, a heating apparatus having the heating element In an image forming apparatus including the heating device as an image heating / fixing unit, even when a heating substrate such as aluminum nitride having excellent thermal conductivity is used, an electric contact with an electrode portion provided on the heating substrate is achieved. Since it is possible to prevent a decrease in the spring constant due to a temperature rise that exceeds the heat resistance temperature of the pressure spring as a target contact, it is possible to eliminate poor contact between the electrode portion and the pressure spring and occurrence of contact burn due to poor conduction, The life and reliability of the heating element and the device can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a film heating type heating device in Example 1.

FIG. 2 is an enlarged cross-sectional model diagram of a main part.

FIG. 3 (a) is a partially cutaway model view of the surface side of a heating element.
(B) Model drawing on the back side

FIG. 4A is a perspective view of a heating body support on which a cylindrical film is externally fitted, and a connector for an AC line and a connector for a DC line. FIG. 4B is a diagram showing two pressurizations as electrical contacts in the connector. Perspective view of spring

FIG. 5A is a vertical cross-sectional model view of a main part of an example in which a first extension arm of a heating element support is formed of a heat radiating member, and FIG.

FIG. 6 is a schematic longitudinal sectional view of a main part of an example in which a heat radiation fin is further added to the heat radiation member.

FIG. 7A is an explanatory view of an example in which a counterbore portion (step portion) is further provided on the bottom surface of the heating element fitting groove of the heating element support;
(B) is a cross-sectional model diagram of the main part.

FIG. 8 is a longitudinal sectional model view of a main part of still another example of the configuration of the heat radiating means.

FIG. 9 is an explanatory diagram of a heat radiating means configuration (heat radiating connector) in the second embodiment.

FIG. 10 is an explanatory diagram of a configuration of a heat radiating unit according to a third embodiment.

FIG. 11 is an explanatory view of a configuration of a heat radiating unit in the fourth embodiment (part 1).

FIG. 12 is an explanatory diagram of a heat radiating means configuration according to the fourth embodiment (part 2).

FIG. 13 is an explanatory view of a configuration of a heat radiating unit in the fourth embodiment (part 3).

FIGS. 14 (a), (b) and (c) are model views of another configuration example of the film heating type heating apparatus.

FIG. 15 is a schematic configuration diagram illustrating an example of an image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating body 2 Heating body support 3 Film 4 Pressure roller P Recording material (Heating material) N Nip part 11 Heating substrate 12 Resistance heating element 13.14,18,19 1st-4th electrode pattern 32 · 32, 37 · 37 Pressure spring 15 · 16 · 22 · 23 Conductive path pattern 17 Surface protection layer 24 Temperature sensing element (thermistor) 31 · 36 Connector for AC line and DC line 41 · 42 · 43 · 44 Heat radiating members 51 and 52 Ducts and fans as air path means

Claims (27)

[Claims] A heating element provided with a heating element, having an electrode section on a heating element substrate heated by the heat generated by the heating element, and contacting a pressure spring as an electrical contact with the electrode section. A heating body, wherein a heat radiating member is arranged at a portion corresponding to a contact portion between the portion and a pressure spring. 2. A heating element provided with a heating element, having an electrode portion on a heating substrate heated by the heat generated by the heating element, and contacting a pressure spring as an electrical contact with the electrode portion. A heating body characterized in that a heat radiating portion extends from an electrode portion of the body substrate to an end of the heating body substrate. 3. A heating element provided with a heating element, having an electrode section on a heating element substrate which is heated by the heat generated by the heating element, and contacting a pressure spring as an electrical contact with the electrode section. A heating element characterized in that a heat radiating portion extends from an electrode portion of the body substrate to an end of the heating body substrate, and a heat radiating member is disposed in the heat radiating portion. 4. The heating device according to claim 1, wherein the heating element is a heating element that generates heat when energized, and the electrode portion is electrically connected to the heating element. body. 5. A temperature detecting element is provided on a heating body substrate,
The heating element according to any one of claims 1 to 4, wherein the electrode portion is electrically connected to the temperature detecting element. 6. The heating element substrate is made of aluminum nitride (Al).
The heating element according to any one of claims 1 to 5, wherein N). 7. A heating element is provided, an electrode portion is provided on a heating element substrate which is heated by the heat generation of the heating element, the electrode section is fixed and supported by a heating element support, and the electrode section is pressurized as an electrical contact. In a heating device that heats a material to be heated by a heating element brought into contact with a spring, a heat dissipating member is disposed at a position corresponding to a contact portion between an electrode portion and a pressure spring of a heating element support that fixedly supports the heating element. A heating device. 8. A heating element provided with a heating element, having an electrode portion on a heating element substrate which is heated by the heat generated by the heating element, fixedly supported by a heating element support, and pressurized as an electrical contact with the electrode section. In a heating device for heating a material to be heated by a heating element brought into contact with a spring, a connector including the pressure spring, and a connector for contacting and fixing the pressure spring to an electrode portion is used as a heat radiating member of the pressure spring. A heating device, characterized in that: 9. A heating element provided with an electrode portion on a heating substrate which is heated by the heat generated by the heating element, fixedly supported by a heating member support, and pressurized as an electrical contact with the electrode portion. A heating device for heating a material to be heated by a heating member brought into contact with a spring, wherein a portion from an electrode portion of the heating substrate to an end of the heating substrate is used as a heat radiating portion. 10. A heating element is provided, a heating substrate heated by the heat of the heating element has an electrode portion, the electrode portion is fixed and supported by a heating member support, and the electrode portion is pressurized as an electrical contact. In a heating device for heating a material to be heated by a heating element brought into contact with a spring, a portion from the electrode portion of the heating substrate to an end of the heating substrate is used as a heat radiating portion, and a heat radiating member is arranged in the heat radiating portion. Heating equipment. 11. An air passage means for air cooling a contact portion between an electrode portion and a pressure spring, a heat radiation member portion, or a heat radiation portion portion. Heating equipment. 12. The heating device according to claim 7, wherein the heating element is a heating element that generates heat when energized, and the electrode portion is electrically connected to the heating element. apparatus. 13. The heating device according to claim 7, wherein a temperature detecting element is provided on the heating element substrate, and the electrode portion is electrically connected to the temperature detecting element. apparatus. 14. The heating substrate is made of aluminum nitride (Al).
The heating device according to any one of claims 7 to 13, wherein N). 15. A heating element provided with an electrode section on a heating substrate which is heated by the heat generated by the heating element, fixedly supported by a heating element support, and pressurized as an electrical contact to the electrode section. A heating element contacted with a spring, and a film having one surface sliding with the heating element and the other surface moving in contact with the material to be heated, and heat from the heating element via the film. A heating device for heating a material to be heated by a heating device, wherein a heat radiating member is arranged at a portion corresponding to a contact portion between an electrode portion and a pressure spring of a heating member support for fixedly supporting a heating member. . 16. A heating element is provided, an electrode portion is provided on a heating element substrate which is heated by the heat generation of the heating element, and is fixed and supported by a heating element support, and the electrode section is pressurized as an electrical contact. A heating element contacted with a spring, and a film having one surface sliding with the heating element and the other surface moving in contact with the material to be heated, and heat from the heating element via the film. A heating device for heating a material to be heated according to (1), wherein a connector including the pressure spring and contacting and fixing the pressure spring to an electrode portion is a heat radiation member of the pressure spring. 17. A heating element provided with an electrode portion on a heating body substrate which is heated by the heat generated by the heating element, fixedly supported by a heating member support, and pressurized as an electrical contact with the electrode portion. A heating element contacted with a spring, and a film having one surface sliding with the heating element and the other surface moving in contact with the material to be heated, and heat from the heating element via the film. A heating device for heating a material to be heated according to (1), wherein a portion from the electrode portion of the heating body substrate to an end of the heating body substrate is a heat radiating portion. 18. A heating element provided with an electrode portion on a heating substrate which is heated by the heat generated by the heating element, fixedly supported by a heating member support, and pressurized as an electrical contact to the electrode portion. A heating element contacted with a spring, and a film having one surface sliding with the heating element and the other surface moving in contact with the material to be heated, and heat from the heating element via the film. A heating device for heating a material to be heated according to (1), characterized in that a portion from the electrode portion of the heating body substrate to an end portion of the heating body substrate is a heat dissipation portion, and a heat dissipation member is arranged in the heat dissipation portion. 19. An air path means for air-cooling a contact portion between an electrode portion and a pressure spring, a heat radiating member, or a heat radiating portion.
The heating device according to any one of the above. 20. The heating device according to claim 15, wherein the heating element is a heating element that generates heat when energized, and the electrode portion is electrically connected to the heating element. apparatus. 21. The heating device according to claim 15, wherein a temperature detecting element is provided on the heating body substrate, and the electrode portion is electrically connected to the temperature detecting element. apparatus. 22. The heating body substrate is made of aluminum nitride (Al).
22. The heating device according to claim 15, wherein N). 23. A pressurizing member for forming a nip by press-contacting a heating element through a film, wherein the material to be heated is sandwiched and conveyed between the film and the pressurizing member of the nip portion and the film is interposed. 23. The heating device according to claim 15, wherein the material to be heated is heated by heat from the heating element. 24. The recording medium according to claim 15, wherein the recording medium is a recording medium carrying an image, and the apparatus is an image heating apparatus for heating the recording medium.
The heating device according to any one of the above. 25. The apparatus according to claim 15, wherein the material to be heated is a recording material carrying an unfixed image, and the apparatus is an image heat fixing device for fixing the unfixed image to the recording material.
25. The heating device according to any one of items 24 to 24. 26. An image forming apparatus comprising: an image forming unit for forming an unfixed image on a recording material; and an image heating and fixing unit for fixing the unfixed image to the recording material. 7. One of the claims 1 to 6
An image forming apparatus, comprising: a heating device comprising the heating element according to any one of claims 7 to 12, or the heating device according to any one of claims 7 to 25. 27. A contact part between the electrode part of the heating element and the pressure spring, a heat radiation member part, or a heat radiation part part,
The image forming apparatus according to claim 26, wherein the image forming apparatus is disposed between a body frame and an exterior of the image forming apparatus.