JP2001093652A - Heating material, heater device and image-forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable, efficient, high-speed on-demand type heating material, a heating device and an image-forming device capable of reducing the area of the substrate by disposing a temperature sensing element in the middle of plural heat generators in a rear side heating type heating material. SOLUTION: This heating material has plural heat generators 2, 2a generating heat by carrying an electric current to a heat resistant insulating substrate 1, and the side of the substrate 1 opposite to the side the heat generators 2a, 2a is the heating side to heat a material to be heated. The heat generators 2a, 2a of the substrate 1 are covered with an insulating layer 4, and a temperature sensing element 7 is disposed in the middle of the heat generators 2 and 2a on the insulating layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating element, a heating apparatus, and an image forming apparatus, for example, having a plurality of heating elements that generate heat when energized on a heat-resistant insulating substrate, and a temperature detecting element to generate heat. The present invention relates to a backside heating type heating element in which a substrate surface opposite to a heating element is a heating surface of a material to be heated, a heating device including the heating element, and an image forming apparatus including the heating device as image fixing means.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a printer or a copying machine, an unfixed image corresponding to target image information formed and carried on a recording material (transfer material sheet, printing paper, etc.) by an electrophotographic process. As a heating device for thermally fixing an image material image (unfixed toner image) to a recording material, a heat roller method has been generally used so far.

A heat fixing device of a heat roller type comprises a metal heating roller (fixing roller) heated by a built-in heat source such as a halogen heater to maintain a predetermined temperature, and an elastic pressure roller pressed against the metal heating roller. A recording medium as a material to be heated is introduced into a press-contact nip portion (fixing nip portion) of the roller and is conveyed by heating the unfixed developer image on the surface of the recording material by heat of the heating roller. This is to fix by pressure.

Recently, from the viewpoint of promoting energy saving,
A film heating type heating device has been proposed, which has higher heat transfer efficiency than the heating device of the heat roller type, has a faster start-up time, shortens the wait time (operates on demand), and saves power. Has also been made.

In this heating apparatus, a material to be heated is brought into close contact with a heating member fixedly supported by a supporting member via a heat-resistant thin-walled film material, and the film material is slid and moved to the heating member to heat the heating member. Is applied to a material to be heated via a film material, and can be used as a fixing device for thermally fixing an unfixed toner image as a permanent fixed image on the surface of a recording material carrying the image.

[0006] Such a film heating type heating apparatus has a heating element of a low heat capacity with a rapid temperature rise, for example, a ceramic substrate having characteristics such as heat resistance, insulation and good thermal conductivity; It is possible to use a so-called ceramic heater having a basic structure of a resistor (heating element) which generates heat by energization provided on the surface of the surface, and to use a thin film having a low heat capacity as a film material. The temperature of the heating body rises, and it is not necessary to supply power to the heating body during standby, and even if the recording material is passed immediately, the heating body is kept at a predetermined temperature until the recording material reaches the fixing portion. Temperature can be sufficiently increased, and the wait time can be reduced and power consumption can be reduced. Further, it has an advantage that the temperature rise inside the image forming apparatus can be reduced, and is effective.

FIG. 5 is a schematic cross-sectional view of a main part of an example of a film heating type heating device (fixing device).

Reference numeral 10 denotes a heating element (hereinafter referred to as a heater), 2
Reference numeral 1 denotes a rigid and heat-resistant heating support member (heater holder (stay), hereinafter referred to as a heater holder) in which the heater 10 is fixedly supported by being inserted into the lower groove 21a.
Reference numeral 2 denotes a heat-resistant and thin film material (hereinafter, referred to as a fixing film), and reference numeral 23 denotes an elastic pressure roller.

The heater 10 fixedly supported on the lower surface side of the heater holder 21 and the elastic pressure roller 23 are pressed against each other with a predetermined pressing force against the elastic pressure roller 23 with the fixing film 22 interposed therebetween so as to have a predetermined width. (Hereinafter, referred to as a fixing nip portion) N.

Generally, a ceramic heater is used for the heater 10, and the heater is heated and controlled to a predetermined temperature by energization. The structure of the heater 10 will be described later.

The fixing film 22 has a thickness of 50 to 100 μm.
m is a heat-resistant film material having a thin single-layer or composite structure, such as polyimide, and has a cylindrical shape. The fixing film 22 is a recording material P on which an unfixed toner image t as a material to be heated is formed and supported between a driving unit (not shown) or an elastic pressure roller 23 so that the image bearing surface side is the fixing film 22 side. When the recording material P is introduced, the fixing nip N
The fixing nip N is conveyed together with the fixing film 22 in close contact with the outer surface of the fixing film 22.

In the fixing nip portion N, the recording material P and the toner image t are transferred by the heater 10 to the fixing film 22.
, And the toner image t is heated and fixed on the surface of the recording material P. The recording material portion that has passed through the fixing nip portion N is transported separately from the outer surface of the fixing film 22. “ta” indicates a heat-fixed toner image.

FIG. 6A is a partially cutaway surface side model view of a ceramic heater 10 which is a heating element used in the above apparatus.
(B) is a back side model view.

Reference numeral 1 denotes a heater substrate having characteristics such as heat resistance, electrical insulation, good thermal conductivity, and low heat capacity. The heater transfers and transports the fixing film 22 and the recording material P, which are the material to be heated, in the fixing nip N. A long and thin ceramic material such as alumina (Al
₂ O ₃ ) plate.

On the heater surface shown in FIG. 6A, reference numeral 2 denotes a resistive layer pattern which is formed at the center of the heater substrate surface in the width direction along the longitudinal direction of the substrate and generates heat when energized. For example, it is formed by applying an electric resistance material paste (resistance paste) such as silver palladium on a narrow band pattern having a thickness of 10 μm and a width of 3 mm by screen printing and firing.

Reference numeral 3 denotes a conductive electrode portion provided on the surface of the substrate by conducting to both ends of the resistance layer pattern 2, respectively. The conductive electrode portion 3 is formed by applying a pattern of a conductive material paste such as Ag on the substrate surface by screen printing or the like, followed by firing.

Reference numeral 4 denotes a heater surface protection layer, for example, a heat-resistant glass layer having a thickness of about 10 μm. The surface of the heater substrate is covered with this surface protective layer 4 except for the conductive electrode portion 3, and the resistive layer pattern 2 is covered with the surface protective layer 4 to be protected from abrasion and the like. The glass layer as the surface protective layer 4 is formed by applying a pattern of a glass paste to the substrate surface by screen printing or the like and firing the glass paste.

On the back side of the heater in FIG. 6B, reference numeral 5 denotes two temperature detection signal lines formed in parallel from one longitudinal end to the center in the longitudinal direction of the rear surface of the heater substrate. An electrode portion connected to the start end of the temperature detection signal line 5 is a chip thermistor as a temperature detection element, and two thermistor electrodes on the thermistor 7 side are respectively connected to the two temperature detection signal lines 5. It is arranged on the back surface of the heater substrate by being joined to the tip with a conductive adhesive.

Both the signal line 5 for temperature detection and the electrode section 6 are A
The conductive material paste, such as g, is formed by applying a pattern on the back surface of the substrate by screen printing or the like, followed by firing.

The heater 10 has its front surface side, that is, the side on which the resistive layer pattern 2 of the heater substrate 1 is formed, exposed downward, and is supported by being inserted into a groove 21a provided along the length on the lower surface of the heater holder 21. Let me do it.

Connectors (not shown) are attached to both ends of the heater 10, and the power supply electric contacts 3 are in elastic contact with the respective energizing electrode portions 3 on both ends of the heater 10. The temperature detection signal line electrode portion 6 on one end of the heater 10 is brought into a state in which the electrical contact for the temperature detection circuit of the mounting connector on that side is in elastic contact with the temperature detection signal line electrode portion 6. The signal line for use (DC line) 5 is electrically connected to a temperature control circuit (not shown).

When AC power is supplied from the power supply circuit to the resistive layer pattern 2 of the heater 10, the resistive layer pattern 2 generates heat over its entire length, and the heater 1
0 rapidly rises in temperature. The temperature rise of the heater 10 is detected by the thermistor 7 disposed on the back side of the heater substrate, and the detected temperature information (DC current) is fed back to the temperature control circuit. The temperature control circuit controls power supply from the power supply circuit to the resistance layer pattern 2 so that the heater temperature detected by the thermistor 7 is maintained at a predetermined substantially constant temperature (fixing temperature). That is, the heater 10 is heated to a predetermined fixing temperature and temperature is controlled.

In the unlikely event that the temperature control system cannot be energized for the resistance layer pattern 2 for some reason, for example, if the power is excessively supplied to the resistance layer pattern 2,
Since the temperature of the heater 10 may rise excessively, as a safety measure, the heater 10 is provided with a safety element such as a temperature fuse and a thermoswitch. Means are provided for urgently shutting off the current supply to the resistance layer pattern 2 by operation.

Further, as another safety measure, by providing the heater substrate 1 with the through holes 8 as shown in FIG. 6, when the temperature of the heater 10 is excessively increased to a predetermined temperature or more, the heater 10 is formed at the through holes 8. Means for automatically causing a horizontal crack including a break in the resistance layer pattern 2 (AC line) starting from the through hole 8 portion in the heater 10 due to the thermal stress of the heater substrate 1 to stop thermal runaway of the heater. Is prepared.

In FIG. 6A, a two-dot chain line 10a indicates a heater lateral crack starting from the through hole 8 described above.

That is, when the temperature of the heater substrate reaches an excessive temperature range, the through hole 8 of the substrate causes the through hole 8 of the substrate.
Temperature unevenness occurs at the boundary between the portion having the unevenness and the portion without the unevenness, and a difference occurs in the degree of thermal expansion of the substrate according to the temperature unevenness. The stress generated at that time causes cracks in the substrate 1 through the through holes 8. The heater 10 is broken laterally 10a, and the resistance layer pattern 2 as a heating element formed on the substrate 1 is also disconnected, so that the thermal runaway of the heater 10 is stopped.

The above two safety measures are often adopted together to form a double safety measure.

In the heater 10 as described above, a relatively inexpensive alumina material is generally used for the heater substrate 1. A ceramic heater using an alumina material as the heater substrate 1 also has a low heat capacity and a rapid temperature rise, and a film heating type heating device (fixing device) using the heater has a much longer wait time than a heat roller type heating device. Although it is possible to shorten the time and save power, etc., in recent years, it has been required to further increase the speed of image forming apparatuses such as printers, and to shorten the wait time. Therefore, a heater having a temperature rising characteristic that is faster than that of a heater having a substrate as a substrate, that is, a heater having a faster temperature rising characteristic has been required.

As a heater meeting such a demand, a heater substrate 1 made of a material having higher thermal conductivity than alumina material, for example, aluminum nitride (hereinafter referred to as Al)
A heater using an N) material as a heater substrate has been proposed.

The AlN substrate has a thermal conductivity 10 times or more higher than that of the alumina substrate, and enables the substrate to be heated more quickly with the same input energy, that is, the heater temperature and the temperature distribution can be made uniform, and the thermal shock resistance is also improved. Since it is about twice as large, there are many advantages in that even when the resistance layer pattern 2 as a heating element is made thinner and used at a high temperature, the substrate is less likely to be damaged by rapid heating.

Paying particular attention to the fact that the AlN substrate has a higher thermal conductivity than the glass coat layer, an AlN substrate is used as the heater substrate, and the substrate is on the heated surface side of the material to be heated, that is, on the side facing the fixing nip portion. A backside heating type (backside heating type) AlN heater having a resistance layer pattern on the back side of the substrate opposite to the front side of the substrate rises more quickly than a heater using an alumina material as a substrate, and has high thermal conductivity. Therefore, it is possible to uniformly and widely heat the entire substrate, and it is possible to maintain a high fixing property even at a high speed.

However, in a fixing device using a heater as described above, a recording material (small-size paper) having a paper passing width smaller than the maximum paper passing width that can be introduced and used in the apparatus is continuously passed. As the heat fixing is performed, in the sheet passing portion of the fixing nip portion, the heat consumed for heating the recording material is compensated by the temperature control system to be maintained at the predetermined temperature, while the heat is not maintained. Since heat is not consumed by the heating of the recording material in the paper portion, heat is accumulated, and the temperature of the non-paper passing portion is higher than the temperature of the paper passing portion maintained and maintained at a predetermined temperature. Paper temperature rise occurs.

If the temperature rise of the non-sheet passing portion is extremely high, there is a problem that the fixing roller bearing, the pressure roller, the fixing film, the film guide stay, and other components around the heating portion are easily damaged by heat. .

In order to solve the above-mentioned problems such as thermal damage and damage to the fixing film, a conventional image forming apparatus prepares a plurality of heaters having different heat distributions in the longitudinal direction of the substrate.
A method is provided in which a sensor for detecting the size of the recording paper is provided, and a heater to be energized is switched according to the paper size, thereby avoiding a temperature rise in a non-paper passing portion.

FIG. 7 is a model diagram of the backside heating type AlN heater 10. On the backside of the AlN substrate 1, resistive layer patterns 2 and 2a as heating elements, an energizing electrode section 3, a thermistor 7 as a temperature detecting element, Temperature detection signal line 5, electrode section 6
Although not shown in the figure, a heat insulating insulating coat layer, for example, a glass coat layer having a thickness of 50 μm is formed on the back surface of the substrate except for the portions of the conductive electrode portion 3 and the electrode portion 6 among the above. I have it.

In the heater 10, the surface of the AlN substrate 1 opposite to the surface on which the resistive layer pattern 2 and the like are provided is the heated surface of the material to be heated, that is, the surface facing the fixing nip.

[0037]

The backside heating type heater is
Although it has many advantages as described above, in the conventional backside heating type heater, the surface of the substrate 1 opposite to the surface on which the resistance layer 2 as the heating element of the substrate 1 is provided, that is, the surface of the substrate 1 is covered. Since the temperature detecting element 7 cannot be provided on the heating material heating surface side, the temperature detecting element 7 must be formed adjacent to the same surface as the resistance layer forming surface on the back surface of the substrate as in the heater of FIG. In this case, from the viewpoint of safety, A
It is necessary to ensure a sufficient distance between the resistance layer pattern 2 for applying the C power and the temperature detection signal line 5 including the temperature detection element (thermistor) 7 which is a DC signal line, and the resistance layer pattern required for heating is required. 2 has a problem that the substrate width is greatly increased as compared with the width of 2, so that the space efficiency is reduced and an AlN substrate having a high material cost is additionally used, which is disadvantageous in cost.

Therefore, the present invention provides a backside heating type heating element, in which a temperature detecting element is arranged in the middle of a plurality of heating elements, so that a highly reliable, high-efficiency, high-speed on-demand type is realized while the substrate area is increased. It is an object of the present invention to obtain a heating element, a heating device, and an image forming apparatus capable of reducing the size of the heating element.

Another object of the present invention is to provide a heating element, a heating apparatus, and an image forming apparatus which can detect the temperatures of a plurality of heating elements with one temperature detecting element and can simplify the apparatus.

[0040]

SUMMARY OF THE INVENTION The present invention provides a heating element, a heating apparatus, and an image forming apparatus, which are characterized by the following.

(1): A heat-resistant insulating substrate has a plurality of heating elements that generate heat when energized, and the surface of the substrate opposite to the side having the heating elements is the heated material heating surface side. In the heating element, the heating element of the substrate is covered with an insulating layer,
On the insulating layer, at an intermediate position between the heating element and the heating element,
A heating element comprising a temperature detection element.

(2) The heating element according to (1), wherein an aluminum nitride material is used as the substrate.

(3) The heating element according to (1) or (2), wherein the insulating layer is a glass coat layer.

(4) A heating device comprising the heating element according to any one of (1) to (3) as a heating element for heating a material to be heated.

(5): A heating body according to any one of (1) to (3), which is fixed and supported, and a film which slides in contact with the surface of the material to be heated of the heating body. A heating device for heating the material to be heated by heat from a heating body through the film.

(6) In the heating device of the above (5),
A heating device comprising: a pressure member that forms a nip portion as a heated material heating portion by being mutually pressed against a heating body with a film interposed therebetween.

(7) The heating device according to any one of (4) to (6), wherein the material to be heated is a recording material carrying an unfixed image, and the material to be heated is determined by heat from a heating body. A heating device for fixing a deposited image on a recording material.

(8): An image forming means for forming an unfixed image on the recording material and a fixing means for thermally fixing the unfixed image on the recording material, wherein the fixing means are provided by the methods (4) to (4). An image forming apparatus, which is the heating apparatus according to any one of the above 7).

<Operation> That is, an insulating layer is coated on a resistance layer as a heating element of a substrate, and a temperature detecting element is disposed on the insulating layer at an intermediate position between the heating element and the heating element. By doing so, even in the case of a backside heating type heating element, it is not necessary to form the heating element and the temperature detecting element on the same surface, and it is possible to avoid an increase in the number of substrate materials to be used.

Further, by disposing the temperature detecting element at an intermediate position between the heating elements, the temperature of a plurality of heating elements can be detected by one thermistor, and the apparatus can be simplified.

[0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment of the present invention will be described.

FIG. 2 shows a schematic configuration of a laser printer as an example of the image forming apparatus according to the present invention.

Reference numeral 11 denotes a drum type electrophotographic photosensitive member as an image carrier, which is rotated at a predetermined peripheral speed (process speed) in the direction of an arrow.

The photosensitive member 11 is primarily charged to a predetermined polarity and potential by a primary charger 12 during its rotation.
Next, the laser beam scanner 13 receives the laser beam scanning exposure L of the target image information, and an electrostatic latent image corresponding to the target image information is formed on the peripheral surface of the photoconductor 11. Next, the latent image is visualized as a toner image by the developing device 14. The toner image is transferred from a paper feeding mechanism (not shown) to a transfer section between the photoreceptor 11 and the transfer unit 15 at a predetermined timing, and is transferred onto the surface of a transfer sheet P as a recording medium which is fed and conveyed. .

The transfer paper P to which the toner image has been transferred through the transfer section is separated from the surface of the photoconductor 11 and
Then, the toner image is introduced into the heat fixing device 18 to receive heat fixation of the toner image, and is printed out to a discharge tray (not shown). Photoconductor 11 after transfer of toner image to transfer paper P
Are removed by a cleaning device 19 to remove residual contaminants such as transfer residual toner, and are repeatedly provided for image formation.

The laser beam scanner 13 includes a semiconductor laser 31 as a light source and a polygon mirror (rotating polygon mirror) 3.
2. An f-θ lens 33, a folding mirror 34 and the like. The semiconductor laser 31 outputs a laser beam modulated corresponding to a time-series electric digital image signal of target image information input to a printer from a host computer, an image reading device, a word processor, or the like (not shown) as an external device. I do.

FIG. 3 is a schematic cross-sectional view of a main part of a film heating type heating device (fixing device) according to the present invention.

Parts common to those in FIG. 5 described above are denoted by the same reference numerals, and the description thereof will not be repeated. As the heater 10, an AlN heater using aluminum nitride as a substrate material is used, and the heater 10 is heated to a predetermined temperature and adjusted to a predetermined temperature by energization.

FIGS. 1A and 1B are schematic views of a main part of the heater 10, in which FIG. 1A is a schematic structural view on the side of a heating element forming surface, and FIG. 1B is a sectional view.

In FIG. 1, reference numeral 1 denotes a heater substrate having characteristics such as heat resistance, electrical insulation, good thermal conductivity, and low heat capacity.
A horizontally long and thin, for example, aluminum nitride plate whose longitudinal direction is perpendicular to the conveying movement direction A of the recording material P.

In the heater surface shown in FIG. 1A, reference numerals 2 and 2a denote resistive layer patterns formed at the center of the heater substrate surface in the width direction along the longitudinal direction of the substrate and generating heat by energization. For example, it is formed by applying an electric resistance material paste (resistance paste) such as silver palladium on a narrow band pattern having a thickness of 10 μm and a width of 3 mm by screen printing and firing.

Reference numeral 3 denotes a conduction electrode portion provided on the substrate surface by conducting to both ends of the resistance layer patterns 2 and 2a, respectively. The conductive electrode portion 3 is formed by applying a pattern of a conductive material paste such as Ag on the substrate surface by screen printing or the like, followed by firing.

Reference numeral 4 denotes a heater surface protective layer, for example, a heat-resistant glass layer having a thickness of about 10 to several tens μm. The surface protective layer 4 is covered except for the conductive electrode portion 3 on the surface of the heater substrate as shown in FIG. Covered and insulated. The glass layer as the surface protective layer 4 is formed by applying a pattern of a glass paste to the substrate surface by screen printing or the like and firing the glass paste.

Reference numeral 7 denotes a chip thermistor as a temperature detecting element for the resistance layer patterns 2 and 2a.
Above and between the resistance layer patterns 2 and 2a. In the present embodiment, each of the resistance layer patterns 2, 2
The distance from a to the chip thermistor 7 is the same. In addition, the distance is not limited to the same distance. For example, when the heat generation amount per unit length in the longitudinal direction of the resistance layer patterns 2 and 2a is different, the distance may be made different based on the ratio of the heat generation amount.

As described above, according to the present embodiment, it is not necessary to form the chip thermistor 7 in the same plane as the surface on which the resistive layer is formed, so that the resistive layer patterns 2 and 2a for applying AC power and the DC It is not necessary to secure a distance from the signal line of the thermistor 7, which is a signal line. Therefore, it is possible to prevent the temperature rise in the non-sheet passing portion, and to achieve high reliability, high efficiency, and high speed of AlN.
It is not necessary to greatly increase the substrate width as compared with the width of the resistance layer patterns 2 and 2a while using the heater, so that the substrate area can be reduced.

Further, the thermistor 7 is arranged at a position exactly intermediate between the heating element 2 and the heating element 2a.
The temperature of 2a can be detected by one thermistor 7, and simplification can be achieved.

Since the substrate can be made smaller and simplified, the cost can be reduced.

<Second Embodiment> This embodiment is different from the first embodiment in that the structure of the heater 10 is the structure shown in FIG.

In FIG. 4, a heating element 2 'and a heating element 2a'
Have the same resistivity and the same thickness t.

The heating elements 2 ′ and 2 a ′ have a wide portion (wide portion: length Lw) and a narrow portion (narrow portion: length Lw).
n), and has a dimension as shown in FIG. 5 in the longitudinal direction of the heater substrate.

In the heating element 2 ', the left and right ends of the substrate are narrow, and the length is left L1 and right L3. The central part is a wide part and the length is L
It is 2.

On the other hand, in the heating element 2a ', the left and right ends of the substrate are wide, and the length is left La1 and right La3. The central portion is a narrow portion, and the length is La2.

Since the resistance per unit length is higher in the narrow portion than in the wide portion, the heat generated in the narrow portion is higher than in the wide portion.
Therefore, in the heater of this configuration, the heating element 2 ′ mainly heats both ends of the heater substrate, and the heating element 2 a ′ mainly heats the central part of the heater substrate.

With this configuration, when forming a heating element on the substrate, it is possible to apply a paste material having the same resistivity, and a screen for forming the heating elements 2 ′ and 2 a ′ on the substrate. The printing process becomes easy, and the cost can be reduced by reducing the number of steps.

Further, since two temperature detections can be performed by one thermistor 7, the cost of the thermistor 7 can be reduced.

In this embodiment, the length of the heating element is given by the following equation. L2 = La1 + La3 L1 + L3 = La2 Therefore, the area of the wide portion is different between the heating element 2 ′ and the heating element 2a.
'Are configured to be equal, and similarly, the areas of the narrow portions are also configured to be equal.

Therefore, the total resistance value of the heating element 2 'and the heating element 2a' are equal, the heat generation amount is equal, and the heating speed is also equal.

Conventionally, when a plurality of energized heating elements are provided, if the heating rate of each energized heating element is different, an abnormality occurs in the start-up of the heat fixing device or in the temperature control unit, and the heating element generates abnormal heat (heating). It becomes difficult to control the heat fixing device when the body runs away, for example). However, in the present embodiment, since the two heating elements generate the same amount of heat, the heating speed becomes uniform,
The temperature of the heat fixing device can be easily controlled. In the upper part, the non-sheet-passing portion is prevented from rising in temperature, and simplification can be achieved while using a highly reliable, highly efficient, high-speed AlN heater.

Further, the size of the substrate can be reduced, and simplification can be achieved.

[0080]

As described above, according to the present invention, by arranging a temperature detecting element in the middle of a plurality of heating elements, a highly reliable, high-efficiency, high-speed on-demand type is achieved. In addition, it is possible to provide a heating element, a heating device, and an image forming apparatus capable of reducing a substrate area.

Further, it is possible to provide a heating element, a heating apparatus, and an image forming apparatus capable of detecting the temperatures of a plurality of heating elements with one temperature detection element and simplifying the apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a first embodiment according to the present invention.

FIG. 2 is a schematic configuration diagram of an image forming apparatus as a first embodiment.

FIG. 3 is a schematic configuration diagram of a heating device according to the first embodiment.

FIG. 4 is a schematic view of a main part of a second embodiment according to the present invention.

FIG. 5 is a schematic configuration diagram of a conventional heating device.

FIG. 6 is a schematic view of a main part of a conventional heating element.

FIG. 7 is a schematic view of a main part of a conventional heating element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate (heat-resistant insulating substrate) 2, 2a Heating element (resistance layer pattern) 3 Current-carrying electrode part 4 Surface protection layer (heat-resistant glass layer) 5 Temperature detection signal line 6 Electrode part (temperature detection signal line electrode part) 7 Temperature detection element (thermistor) 8 Through hole 10 Heating body (ceramic heater) 11 Photoconductor 12 Primary charger 13 Laser beam scanner 14 Developing unit 15 Transfer unit 17 Transport unit 18 Thermal fixing unit 19 Cleaning unit 21 Heater holder 21a Groove 22 Fixing Film 23 Pressing member (elastic pressing roller) 31 Semiconductor laser 32 Polygon mirror (rotating polygon mirror) 33 Lens 34 Mirror A Transporting direction N Fixing nip P Recording material (transfer paper)

Continued on the front page F-term (reference) 2H033 AA21 BA26 BA32 BE03 3K034 AA02 AA04 AA16 AA34 AA37 BA05 BA13 BA18 BB06 BB14 BC04 BC12 BC25 BC28 CA17 CA22 CA32 DA05 EA07 HA01 HA10 JA01 JA10 3K058 AA02 AA81 CE21 CE DA01

Claims (8)

[Claims] 1. A heating element having a plurality of heating elements that generate heat when energized on a heat-resistant insulating substrate, wherein a surface of the substrate opposite to the side having the heating elements is a heated surface of a material to be heated. 3. The heating element according to claim 1, wherein a heating element of the substrate is covered with an insulating layer, and a temperature detecting element is disposed on the insulating layer at a position between the heating element and the heating element. 2. The heating element according to claim 1, wherein an aluminum nitride material is used as the substrate. 3. The heating element according to claim 1, wherein
A heating element, wherein the insulating layer is a glass coat layer. 4. A heating device comprising the heating element according to claim 1 as a heating element for heating a material to be heated. 5. The heating body according to claim 1, which is fixed and supported, and a film that slides and moves in contact with a heated surface of a material to be heated of the heating body. A heating device for heating a material to be heated by heat from a heating body through the heating device. 6. The heating device according to claim 5, further comprising a pressing member that forms a nip portion as a heating target heating portion by mutually pressing the heating member with the film interposed therebetween. 7. The heating device according to claim 4, wherein the material to be heated is a recording material carrying an unfixed image, and the unfixed image is covered by heat from a heating body. A heating device for fixing to a recording material. 8. An image forming device for forming an unfixed image on a recording material, and a fixing device for thermally fixing the unfixed image to the recording material, wherein the fixing device is any one of claims 4 to 7. 1
An image forming apparatus, which is the heating apparatus according to any one of the preceding items.