JPH1184922A - Heating device, fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely melt a temperature fuse to prevent much further temperature rise and to realize image fixation excellent in quality by making a contact surface between a surface heater where the resistance value distribution of a heating resistor is constant and the supporting board of the surface heater flat and making the thickness of the supporting board with which the temperature fuse contacts thinner than the thickness of the supporting board with which the temperature fuse does not contact. SOLUTION: The contact surface between the surface heater 1 and the supporting board 6 is made flat and the thickness of the board 6 with which the temperature fuse 7 contacts is made thinner than the thickness of the board 6 with which the fuse 7 does not contact. Thus, heat conduction to the fuse 7 is improved, and the fuse 7 is surely actuated when the temperature of the heater 1 abnormally rises. When the temperature of the heater 1 abnormally rises at the time of heating, heat due to the abnormal temperature rise is rapidly transmitted to the fuse 7 through the thin part 6a of the board 6 and the fuse 7 is melted. As a result, a contact line with a power source is cut off and much further temperature rise is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device having a planar heater, a fixing device for heating and fixing an unfixed toner image on a material to be heated using the heating device as a heat source, and a laser beam printer having the fixing device. , Laser beam FAX
And the like.

[0002]

2. Description of the Related Art FIG. 8 is a configuration diagram showing a conventional heating device. 8, reference numeral 101 denotes a planar heater. The planar heater 101 has a primary electrode 103 to which a power supply (not shown) is connected on a planar substrate 102 having good heat conductivity.
One end is connected to the primary electrode 103 and the other end is connected to each other.
And a secondary electrode 105 from which the output of a temperature sensor (not shown) is to be taken out.

FIG. 9 is an enlarged side view of a portion A in FIG.
06 is a support for the sheet heater 101, 107 is a support 10
6 is filled with an adhesive 108, and is a thermal fuse fixed to the support 106 with the adhesive 108. The thermal fuse 107 is connected between the primary electrode 103 and the power supply via a lead wire 107a. It is connected to the.

Next, the operation will be described.

The heat is applied to the heating resistor 104 via the temperature fuse 107 and the primary electrode 103. Due to the heat generated by the heating resistor 104 due to the energization, the planar substrate 102, that is, the planar heater 101, rises in temperature, and heats a material to be heated such as a sheet material that moves in contact with the planar heater 101.

[0006]

Since the conventional heating device is configured as described above, the resistance distribution of the heating resistor of the planar heater at the temperature fuse mounting portion changes depending on the amount of the adhesive. For this reason, there is a problem that the heatability of the thermal fuse attachment portion changes according to this change, and it is difficult to control the temperature.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and eliminates the use of an adhesive to keep the resistance value distribution of a heating resistor constant and to shut off a power supply line when an abnormal temperature rise occurs. It is an object of the present invention to obtain a heating device capable of reliably operating a thermal fuse before performing the operation.

Another object of the present invention is to provide a fixing device that uses the above-described heating device as a heat source and reliably heats and fixes an unfixed toner image on a material to be heated.

Another object of the present invention is to provide an image forming apparatus capable of performing high quality fixing by applying the above fixing device.

[0010]

SUMMARY OF THE INVENTION The present invention provides a heating device, a fixing device, and an image forming apparatus having the following features.

(1) A heating resistor printed and fired on a planar substrate having good thermal conductivity, an electrode pattern for supplying power to the heating resistor, and an electrode pattern for recognizing an output from a temperature detecting element. In a heating device in which a heater, a support for supporting the planar heater, and a temperature fuse connected between the electrode pattern and a power supply are in contact with the inside of the support, the resistance value distribution of the heating resistor is constant. Wherein the contact surface between the planar heater and the support is flat, and the thickness of the support with which the thermal fuse contacts is made thinner than the thickness of the support with which the thermal fuse does not contact. Heating equipment.

(2) A heating resistor printed and baked on a planar substrate having good thermal conductivity, an electrode pattern for supplying power to the heating resistor, and an electrode pattern for recognizing an output from the temperature detecting element. A heater, a support that supports the planar heater, and a heating device that contacts a temperature fuse connected between the electrode pattern and a power supply to the inside of the support, wherein the temperature fuse is in contact with the support. A heating device, wherein a slit-shaped counterbore is provided on the temperature fuse mounting surface side.

(3) A heating resistor printed and baked on a planar substrate having good thermal conductivity, an electrode pattern for supplying power to the heating resistor, and an electrode pattern for recognizing an output from the temperature detecting element. A heater, a support that supports the planar heater, and a heating device that contacts a temperature fuse connected between the electrode pattern and a power supply to the inside of the support, wherein the temperature fuse is in contact with the support. A heating device, wherein the thermal conductivity of a contact portion is made better than the thermal conductivity of a non-contact portion of the support that does not contact the thermal fuse.

(4) A heating resistor printed and baked on a planar substrate having good thermal conductivity, an electrode pattern for supplying power to the heating resistor, and an electrode pattern for recognizing an output from the temperature detecting element. A heater, a support that supports the planar heater, and a heating device that contacts a temperature fuse connected between the electrode pattern and a power supply to the inside of the support, wherein the temperature fuse is in contact with the support. A heating apparatus, wherein the thickness of the support is not greater than the thickness of the support that does not come into contact with the thermal fuse, and the thickness of the planar heater facing the support is increased by the reduced thickness of the support.

(5) A fixing device comprising the heating device according to any one of (1) to (4) as a heat source for heating and fixing an unfixed toner image on a material to be heated. Device.

(6) An image forming process means for forming an unfixed toner image on the material to be heated, and the fixing device according to (5), wherein the unfixed toner image is heated and fixed on the material to be heated. An image forming apparatus comprising:

[0017]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is a configuration diagram showing a heating device according to the first embodiment. In FIG. 1, reference numeral 1 denotes a planar heater. The planar heater 1 has a primary electrode 3 to be connected to a power source (not shown) on a planar substrate 2 having good heat conductivity, and one end connected to the primary side. It comprises a pair of strip-shaped heating resistors 4 connected to the electrodes 3 and the other ends connected to each other and printed and fired on a planar substrate, and a secondary electrode 5 from which an output of a temperature sensor (not shown) is to be taken out. I have.

FIG. 2 is an enlarged side view of an essential part of FIG. 1. The contact surface between the planar heater 1 and the support 6 is flattened, and the thickness of the support 6 with which the temperature fuse 7 comes into contact is determined by the temperature. The thickness is smaller than the thickness of the support table at the portion where the fuse does not contact. For example, the thickness of the support 6 to which the thermal fuse 7 contacts is 0.7 mm, and the thickness of the support 6 to which the thermal fuse 7 does not contact is 2.5 mm. When the heat transfer is improved and the temperature of the planar heater 1 rises abnormally, the thermal fuse operates reliably and the primary line, that is, the connection line to the power supply can be cut off. The thermal fuse 7 is connected between the primary electrode 3 and a power supply via a lead wire 7a.

Next, the operation will be described.

The heating resistor 4 is energized via the temperature fuse 7 and the primary electrode 3. Due to the heat generated by the heat generating resistor 4 due to the energization, the planar substrate 2, that is, the planar heater 1 is heated, and the material to be heated such as a sheet material that moves in contact with the planar heater 1 is heated. When the planar heater 1 is abnormally heated during this heating, the heat due to the abnormally elevated temperature is quickly transmitted to the thermal fuse 7 via the thin portion 6a of the support base, and the thermal fuse is blown. As a result, the connection line to the power supply is cut off, and further temperature rise is prevented.

Embodiment 2 FIG. FIG. 3 is a configuration diagram showing a heating device according to the second embodiment. The same parts as those in the first embodiment shown in FIG. Reference numeral 8 denotes a slit-shaped counterbore provided at the position of the support base to which the thermal fuse 7 is to be mounted. For example, the thickness of the support 6 to which the thermal fuse 7 contacts is 2.5 mm, and a slit provided on the side to which the thermal fuse 7 contacts is 2 mm in the longitudinal direction.
mm, 2 mm in the width direction, and 1.8 mm in depth.
When the temperature of the planar heater 1 is abnormally increased, the heat generated by the abnormally increased temperature is transmitted to the thermal fuse 7 via the counterbore 8 and the thermal fuse is blown. As a result, the connection line to the power supply is cut off, and further temperature rise is prevented.

Embodiment 3 FIG. FIG. 4 is a configuration diagram showing a heating device according to the third embodiment. The same parts as those in the first embodiment shown in FIG. Reference numeral 9a denotes a contact portion where the thermal fuse 7 comes into contact with the support 6 and the contact portion 9a is made better than the thermal conductivity of the non-contact portion 9b of the support 6 where the thermal fuse 7 does not contact. As a result, the transfer of heat from the planar heater 1 to the thermal fuse 7 is improved, and when the planar heater 1 abnormally rises in temperature, the heat due to the abnormal temperature rise is quickly transmitted to the thermal fuse 7 via the contact portion 9a. The temperature fuse is blown. As a result, the connection line to the power supply is cut off, and further temperature rise is prevented.

Embodiment 4 FIG. 5 is a configuration diagram showing a heating device according to the fourth embodiment. The same parts as those in the first embodiment shown in FIG. In the fourth embodiment, the thickness of the support 6 to which the thermal fuse 7 contacts is made thinner than the thickness of the support to which the thermal fuse 7 does not contact, and the thickness of the support 6 is reduced by the reduced thickness. The thickness change portion 1a of the planar heater 1 that is opposed to and abuts the change portion 10 is made thick. For example, the thickness of the support 6 to which the thermal fuse 7 does not contact is 2.5 mm, the thickness of the support 6 to which the thermal fuse 7 contacts is 2 mm, and the planar heater 1 is flat to the support 6 to which the thermal fuse 7 contacts. The thickness of the sheet heater is increased by 0.5 mm so as to make contact with the sheet heater.

As a result, the transfer of heat from the sheet heater 1 to the thermal fuse 7 is improved, and when the sheet heater abnormally rises in temperature, the heat due to the abnormal temperature rise is changed to the thickness changing portions 10 and 1a.
And is smoothly transmitted to the thermal fuse 7 through the fuse. As a result, the connection line to the power supply is cut off, and further temperature rise is prevented.

Embodiment 5 FIG. 6 shows the planar heater 1 described above.
1 is a cross-sectional view illustrating a fixing device according to the present invention to which the present invention is applied.
In the figure, reference numeral 11 denotes a heater holder on a semicircular arc which accommodates and supports the planar heater 1 in a concave portion 11a, and 12 denotes a cylindrical fixing film which is rotated and conveyed along the heater holder 11.
Reference numeral 3 denotes a total pressure of 4 to 15 k applied to the fixing film 12 by the sheet heater 1.
A pressure roller which presses at about gf to form a nip N between the fixing film and the fixing film. This pressure roller 13 is provided with a protective layer 13c on the surface of a roller 13b made of heat-resistant rubber having a central shaft 13a. It is a thing.

The fixing film 12 has a film pressure of 100 μm in order to reduce the heat capacity and improve the quick start property.
m, more preferably 40 μm or less and 20 μm or more PTEE, PEA, PP having heat resistance, releasability and durability.
S single-layer film or PTFE, P on the film surface such as polyimide, polyamide imide, PEEK, PES, etc.
It is composed of a composite film coated with FA and FEP as a release layer.

Next, the operation will be described. The heated material 15 having the unfixed toner image 14 formed on the surface thereof includes a pressure roller 13 which is rotated in the direction indicated by an arrow by a driving source (not shown) with the unfixed toner image 14 facing the fixing film 12. When the sheet is fed between the fixing film 12 and the passively rotating fixing film 12, the sheet is heated by the sheet heater 1 when passing through the nip while being sandwiched between the two, and the unfixed toner image 14 is melted and heated. It is fixed on the material 15.

Embodiment 6 FIG. FIG. 7 is a schematic diagram showing an image forming apparatus of the present invention to which the fixing device of FIG. 6 is applied. In FIG. 7, reference numeral 21 denotes a photosensitive drum, on which a photosensitive material such as OPC, amorphous Se, amorphous Si or the like is formed on a substrate on a cylinder made of aluminum, nickel or the like.

The photosensitive drum 21 is driven to rotate in the direction of the arrow, and its surface is first uniformly charged by a charging roller 22 as a charging device. Next, scanning exposure is performed by a laser beam 23 that is ON / OFF controlled according to image information, and an electrostatic latent image is formed. This electrostatic latent image is developed and visualized by the developing device 24. As a development method, a jumping development method, a two-component development method, an FEED development method, or the like is used, and a combination of image exposure and reversal development is often used. The photosensitive drum 21, charging roller 22, laser beam 23, developing device 2
4 constitutes an image forming process means.

The visualized toner image is transferred from a photosensitive drum 21 onto a transfer material 15 as a heated material conveyed at a predetermined timing by a transfer roller 25 as a transfer device. At this time, the transfer material 15 is nipped and conveyed between the photosensitive drum 1 and the transfer roller 25 with a constant pressing force. The transfer material 15 to which the toner image has been transferred is conveyed to the fixing device 26 shown in FIG. 6 and fixed as a permanent image.

On the other hand, the transfer residual toner remaining on the photosensitive drum 21 is removed from the photosensitive drum 21 by the cleaning device 27, and the photosensitive drum 21 is used for the next image formation.

[0033]

As described above, according to the present invention, the contact surface between the planar heater and the support base of the planar heater, in which the resistance value distribution of the heating resistor is constant, is flattened so that the thermal fuse contacts the planar heater. The thickness of the support table is made thinner than the thickness of the support table to which the thermal fuse does not contact. When the temperature of the planar heater 1 rises abnormally, the heat due to the abnormal temperature rise causes the thickness of the support table to become thin. It is quickly transmitted to the thermal fuse via the part and the thermal fuse blows. As a result, the connection line to the power supply is cut off, and further temperature rise is prevented.

Further, according to the present invention, since a slit-shaped counterbore is provided on the side of the temperature fuse mounting surface of the support base with which the temperature fuse comes into contact, heat transfer to the thermal fuse via the counterbore is provided. It is performed well, and when the temperature rises abnormally, the thermal fuse is surely blown. As a result, the connection line to the power supply is cut off, and further temperature rise is prevented.

Also, the present invention is configured such that the thermal conductivity of the contact portion of the support that contacts the thermal fuse is made better than the thermal conductivity of the non-contact portion of the support that does not contact the thermal fuse. When the temperature rises abnormally, the thermal fuse is surely blown, and the connection line to the power supply is cut off to prevent the temperature from further rising.

Further, according to the present invention, the thickness of the support table contacted by the thermal fuse is made smaller than the thickness of the support table not contacted by the thermal fuse, and the support table is opposed to the support table by the reduced thickness. Since the thickness of the planar heater is increased, when the temperature is abnormally raised, the thermal fuse is surely blown, and the connection line to the power supply is cut off to prevent the temperature from being raised further.

Further, since the fixing device is constituted by using the above-described heating device as a heat source, there is an effect that the unfixed toner on the material to be heated can be fixed efficiently and reliably without damage and failure.

Further, by applying this heating device to an image forming apparatus, there is an effect that a high quality image can be reliably fixed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a heating device according to a first embodiment.

FIG. 2 is an enlarged side view of a main part of FIG.

FIG. 3 is a configuration diagram illustrating a heating device according to a second embodiment.

FIG. 4 is a configuration diagram showing a heating device according to a third embodiment.

FIG. 5 is a configuration diagram showing a heating device according to a fourth embodiment.

FIG. 6 is a cross-sectional view showing a heat fixing device according to the present invention to which the above-described heating device is applied.

7 is a schematic diagram illustrating an image forming apparatus of the present invention to which the fixing device of FIG. 6 is applied.

FIG. 8 is a configuration diagram showing a conventional heating device.

FIG. 9 is an enlarged side view of a main part of FIG. 6;

[Explanation of symbols]

1 planar heater, 2 planar substrate, 4 heating resistor, 6
Support base, 6a Thin part, 7 Thermal fuse, 8
Counterbore part, 9a contact part, 9b non-contact part, 21
Photosensitive drum (image forming process means), 22 charging roller (image forming process means), 23 laser beam (image forming process means), 24 developing device (image forming process means).

Claims (6)

[Claims] 1. A planar heater having a heating resistor printed and baked on a planar substrate having good thermal conductivity, an electrode pattern for supplying power to the heating resistor, and an electrode pattern for recognizing an output from a temperature detecting element. A support for supporting the planar heater, and a heating device for contacting a temperature fuse connected between the electrode pattern and a power source to the inside of the support, wherein a resistance value distribution of the heating resistor is constant. The contact surface between the sheet heater and the support is flat, and the thickness of the support with which the thermal fuse contacts is made thinner than the thickness of the support with which the thermal fuse does not contact. Heating equipment. 2. A planar heater having a heating resistor printed and baked on a planar substrate having good thermal conductivity, an electrode pattern for supplying power to the heating resistor, and an electrode pattern for recognizing an output from a temperature detecting element. And a support for supporting the planar heater, and a heating device for contacting a temperature fuse connected between the electrode pattern and a power source to the inside of the support, wherein the support for the thermal fuse contacts the A heating device, wherein a slit-shaped counterbore is provided on the side where the thermal fuse is mounted. 3. A heating element having a heating resistor printed and baked on a sheet substrate having good heat conductivity, an electrode pattern for supplying power to the heating resistor, and an electrode pattern for recognizing an output from a temperature detecting element. And a support for supporting the planar heater, and a heating device for contacting a temperature fuse connected between the electrode pattern and a power supply to the inside of the support, wherein the contact of the support with which the temperature fuse contacts is provided. A heating device, wherein the thermal conductivity of the portion is better than the thermal conductivity of a non-contact portion of the support where the thermal fuse does not contact. 4. A planar heater having a heating resistor printed and baked on a planar substrate having good thermal conductivity, an electrode pattern for supplying power to the heating resistor, and an electrode pattern for recognizing an output from a temperature detecting element. And a support for supporting the planar heater, and a heating device for contacting a temperature fuse connected between the electrode pattern and a power source to the inside of the support, wherein the thickness of the support for contact with the temperature fuse is provided. A heating device, wherein the thickness is made thinner than the thickness of the support base to which the thermal fuse does not come in contact, and the thickness of the opposed planar heater is increased by the reduced thickness of the support base. 5. A fixing device comprising the heating device according to claim 1 as a heat source for heating and fixing an unfixed toner image on a material to be heated. 6. An image forming process means for forming an unfixed toner image on a material to be heated, and a fixing device according to claim 5, wherein said fixing device heats and fixes said unfixed toner image on said material to be heated. Image forming apparatus.