JPH11102769A - Heating apparatus, fixing apparatus, and image-forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating apparatus with high safety and high usability, capable of surely shutting off automatically power supply with respect to a heating resistor at an abnormal rise of temperature, and moreover, capable of automatically restarting power supply when the temperature falls to a prescribed value. SOLUTION: In a heating apparatus having heating resistors 5a and 5b heated on a surface of a planar substrate 2 through power supply, and a planar heater 1 connected to the heating resistors, and forming a primary side electrode pattern to which a power supply connector 8 is mounted, a feeder path for the heating resistor is provided with bimetal type switching means 9 in which two or more types of metals 9a and 9b with their different heat expansion is formed into a layer shape.

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 melting an unfixed toner image on a material to be heated by 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. 7 is a structural view showing a conventional planar heater, and FIG. 7 (a) is a side view of the planar heater showing an electrical contact state of a connector and a non-contact state of a primary electrode pattern. 7
(B) is a plan view of the planar heater in that state, FIG.
FIG. 7C is a side view of the planar heater showing a contact state between the electrical contact of the connector and the primary electrode pattern, and FIG. 7D is a plan view of the planar heater in that state.

In FIG. 7, reference numeral 101 denotes a sheet heater. The sheet heater 101 has a primary side to which a power source (not shown) printed and baked is connected to one end of a sheet substrate 102 having good heat conductivity. An electrode pattern 103a, 103b, a pair of strip-shaped heating resistors 105a, one end of which is connected to the primary electrode patterns 103a, 103b and the other end of which is connected by a connection pattern 104, and printed and fired in parallel on the planar substrate;
105b, and secondary electrode patterns 106a and 106b printed and fired on the other end of the planar substrate 102 so as to extract an output from a temperature sensor (not shown). An insulating protective layer 107 such as glass is formed on the surface.

The above-mentioned primary side electrode patterns 103a, 103
b has a recess 108a so that it can be mounted on the planar substrate from the side of the planar substrate 102, and the primary electrode pattern 10
An electrical contact 109 is provided for contacting 3a, 103b. 110 is a power source (not shown) for connecting the electric contact 109 to a power source (not shown).
Lead wire to be connected to

Next, the operation will be described.

As shown in FIGS. 7A and 7B, when the connector 108 is not mounted on the electrode patterns 103a and 103b, the heating resistors 105a and 105b are disconnected from the power supply and do not generate heat.

On the other hand, as shown in FIGS. 7C and 7D,
When the connector 108 is attached to the electrode patterns 103a and 103b, the primary electrode patterns 103a and 103b
Electricity is applied to the heating resistors 105a and 105b through the electrical contacts 109 and the lead wires 110 that come into contact with the heating resistors, and the heating resistors generate heat.

This planar heater has a low heat capacity and a rapid temperature rise,
The power supply to the heating resistor is controlled by a temperature adjustment system including a temperature detection element, and the temperature is adjusted and managed to a predetermined use temperature. When the temperature of the sheet heater is abnormally raised to a temperature equal to or higher than the upper limit temperature of use by providing a safety device such as a temperature fuse, the operation of the safety device is configured to cut off the current supply to the heating resistor. I have.

[0009]

Since the conventional heating device is configured as described above, an abnormal temperature rise is detected using a temperature fuse or the like, and this detection signal is taken out from the secondary electrode pattern. The power supply to the heating resistor is stopped by performing processing such as opening a power switch based on the detection signal. However, if the temperature control becomes impossible due to a malfunction of the circuit, the automatic return becomes impossible, and the serviceman is disabled. And other problems, such as the necessity of repair and the like, resulting in increased service costs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and when the abnormal temperature rises, the power supply to the heating resistor can be cut off automatically and reliably, and the temperature drops to a predetermined value. It is an object of the present invention to provide a highly safe and easy-to-use heating device capable of automatically restarting power supply when power is supplied.

Another object of the present invention is to provide a highly safe fixing device that uses the above-described heating device as a heat source and reliably melts 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 fixing device.

[0013]

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 apparatus having a heating resistor having a heating resistor formed on the surface of a sheet substrate by heating and a primary electrode pattern connected to the heating resistor and having a connector for power supply mounted thereon. 2. The heating device according to claim 1, further comprising a bimetallic opening / closing means in which two or more kinds of metals having different thermal expansions are formed in a layer on a power supply path for the heating resistor.

(2) The heating device according to claim 1, wherein the bimetallic opening / closing means is provided in the middle of a power supply pattern for the heating resistor.

(3) The heating device according to claim 1, wherein the bimetallic opening / closing means is provided at an electrical contact portion of the connector.

(4) The bimetallic opening / closing means is provided on the primary electrode pattern.
A heating device as described.

(5) The heating apparatus according to any one of claims 1 to 4, wherein the bimetallic switching means includes an insulating cover which can be opened and closed on a contact switching side.

(6) The heating device according to any one of (1) to (5), and a material to be heated having an unfixed toner image is pressed against a sheet heater to form an unfixed toner on the material to be heated. A fixing device comprising: a heat-resistant pressurizing means for fusing and fixing an image.

(7) An image forming process means for forming an unfixed toner image on the material to be heated, and the fixing device according to claim 6, wherein the unfixed toner image is fused and fixed on the material to be heated. Image forming device.

[0021]

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 planar heater 1 according to Embodiment 1 of the present invention.
1A is a side view of a planar heater showing a contact state between an electrical contact of a connector and a primary electrode pattern, FIG. 1B is a plan view of the planar heater in that state, and FIG. FIG. 1D is a side view of the sheet heater showing a non-contact state between the electrical contact and the primary electrode pattern, and FIG. 1D is a plan view of the sheet heater in that state.

In FIG. 1, reference numeral 1 denotes a planar heater. The planar heater 1 is a primary electrode to which a power source (not shown) printed and fired is connected to one end of a planar substrate 2 having good heat conductivity. A pair of strip-shaped heating resistors 5a and 5b, one end of which is connected to the primary electrode pattern 3 and the other end of which is connected to the connection pattern 4 and which is printed and fired on the planar substrate, and a temperature sensor (not shown); , The secondary electrode pattern 6a printed and fired on the other end of the planar substrate 2 so as to take out the output from
6b, and an insulating protective layer 7 made of glass or the like is formed on the surfaces of the heat generating resistors 5a and 5b.

Connector 8 to be attached to primary electrode 3
Has a concave portion 8a so that it can be attached to the planar substrate 2 from the side thereof, and an electrical contact 9 for contacting the primary electrode pattern 3 is provided in the concave portion 8a. The electrical contacts 9 are made of two or more kinds of metals 9 having different coefficients of thermal expansion.
a. 9b is a contact configuration as a bimetallic opening / closing means in which 9b is adhered in a layer. When the electrical contact 9 is mounted on the planar substrate 2, the primary electrode pattern 3
In order to make contact with the primary electrode pattern, when the heating resistors 5a and 5b are at or below a predetermined temperature (during normal use), the primary electrode is maintained while maintaining the convex shape. It is in a power supply enabled state in contact with the pattern. Reference numeral 16 denotes a lead wire for connecting the electric contact 9 to a power supply (not shown).

On the other hand, when the heating resistors 5a and 5b are at a predetermined temperature or higher (abnormal temperature rise), the electrical contacts 9 of the connector 8 are made of a metal 9a having a higher coefficient of thermal expansion than a metal 9b having a lower coefficient of thermal expansion. The electrical contact 9 expands, and the shape of the electrical contact 9 is convex (FIG. 1A) in the direction of the primary-side electrode pattern.
By operating in the state of (c)), the electrical contact 9 and the primary electrode pattern 3 are brought into a non-contact state, so that the power supply can be surely shut off urgently, and the heat generating resistors 5a,
The abnormal temperature rise of 5b can be stopped.

After the emergency shutoff of the power supply, the heat generating resistors 5a and 5b recover to a predetermined temperature or less, so that the electrical contact 9 is made of a metal 9a having a high coefficient of thermal expansion and a metal 9a having a low coefficient of thermal expansion. 9b, the electrical contact 9 operates from a concave (FIG. 1 (c)) to a convex (FIG. 1 (b)) state in the primary electrode pattern direction, whereby the electrical contact is formed. The contact 9 and the primary electrode 3 return to the contact state, and the power can be automatically restarted.

Embodiment 2 FIG. FIG. 2 is a configuration diagram showing a planar heater 1 according to Embodiment 2 of the present invention.
FIG. 2A is a side view of a planar heater showing a contact state between an electrical contact of a connector and a primary electrode pattern, FIG. 2B is a plan view of the planar heater in that state, and FIG. FIG. 2D is a side view of the planar heater showing a non-contact state between the electrical contact and the primary electrode pattern, and FIG. 2D is a plan view of the planar heater in that state.

The electric contact 9 has on its surface insulating covers 10a and 10b having a spring property which can be opened and closed. The insulating covers 10a and 10b are connected to the electric contact 9 and the primary side electrode pattern 3 when closed. Is reliably shut off, and the electrical contact 9 and the primary-side electrode pattern 3 can be brought into contact with each other in the open state. Since the other configuration is the same as that of the first embodiment shown in FIG. 1, the same portions are denoted by the same reference numerals, and redundant description will be omitted. Next, the operation will be described.

During normal use, the insulator covers 10a, 10b
As shown in FIG. 2 (a), the electric contact 9 is pressed by the convex electric contact 9 to be in an open state, and the electric contact 9 and the primary side electrode pattern 3 are surely brought into contact with each other, so that the heating resistors 5a, 5
b is energized.

FIG. 2C shows that the metal 9a having a high thermal expansion coefficient of the electrical contact portion 9 expands from the metal 9b having a low thermal expansion coefficient when the temperature of the heating resistors 5a and 5b exceeds a predetermined temperature. The electric contact 9 and the primary electrode pattern are activated by operating the electric contact 9 in a state of being convex in the direction of the primary electrode pattern (from FIG. 2A to concave (FIG. 2C)). 3 is in a non-contact state, and the insulator covers 10a, 10
When b is closed, the power supply is surely shut off urgently,
The abnormal heating of the heating resistors 5a and 5b is stopped. In this case, by defining the shape (length and the like) of the insulator covers 10a and 10b, the creepage distance between the electrical contact 9 and the primary-side electrode pattern 3 can be ensured in the closed state.

When the heating resistors 5a and 5b recover to a predetermined temperature or lower after the power supply emergency shutoff, the electrical contacts 9 are turned off.
The metal 9a having a high coefficient of thermal expansion shrinks more than the metal 9b having a low coefficient of thermal expansion, and the shape of the electrical contact 9 is changed from a concave (FIG. 2C) to a primary electrode pattern (FIG. 2C). 2
(A)), when the insulator covers 10a and 10b are opened, the electrical contacts 9 and the primary side electrode pattern 3 return to the connected state, and the power supply is automatically restarted. Can be.

Embodiment 3 FIG. FIG. 3 is a configuration diagram showing a planar heater 1 according to Embodiment 3 of the present invention.
3A is a plan view of the planar substrate 1, FIG. 3B is a rear view thereof, FIG. 3C is a side view thereof, and FIG. 3D is a side surface of a main part of the planar substrate during normal use. FIG. 3E is an enlarged side view of a main part of the planar substrate during abnormal temperature rise.

In the third embodiment, the middle of the power supply patterns 12a, 12b formed on the back surface of the planar substrate 2 and connected to the primary electrode patterns 3 on the surface of the planar substrate via the through holes 11a, 11b. Two or more kinds of metals 9a having different thermal expansion coefficients so as to separate and separate the divided portions 12;
9b is provided with an electrical contact 9 as a bimetallic opening / closing means in which the electrical contact 9 is connected to the power supply pattern 12b at one end and the power supply pattern 1 at the other end.
When the temperature is equal to or less than a predetermined temperature (during normal use), the contact state is maintained and the power can be supplied. The other configuration of the planar heater 1 is the same as that of the first embodiment shown in FIG. 1, and therefore, the same portions are denoted by the same reference numerals and the description thereof will not be repeated.

Next, the operation will be described.

FIG. 3E shows that when the heating resistors 5a and 5b are at a predetermined temperature or higher, the metal 9 having a high coefficient of thermal expansion due to abnormal temperature rise is used.
a expands from the metal 9b having a low coefficient of thermal expansion,
Is in contact with the power supply pattern 12a (FIG. 3).
By operating from (d)) to the non-contact state (FIG. 3 (e)), the power supply can be surely shut off urgently, and abnormal heating of the heating resistors 5a and 5b can be stopped.

After the emergency shutoff of the power supply, the heating resistor 5
When the a and 5b recover to a predetermined temperature or less, the shape of the electrical contact 9 is changed from the non-contact state (FIG. 3E) to the power supply pattern 12a from the contact state (FIG. 3D). By doing so, the power supply can be automatically restarted.

Embodiment 4 FIG. FIG. 4A is a configuration diagram illustrating a planar heater 1 according to a fourth embodiment of the present invention. FIG. 4A is a plan view of the planar heater, and FIG. 4B is a diagram illustrating electrical contacts of a connector and primary electrode patterns. FIG. 4 (c) is a side view of the planar heater showing the contact state, FIG. 4 (c) is a plan view of the planar heater in that state, and FIG. 4 (d) is a plane showing the electrical contact of the connector and the non-contact state of the primary electrode pattern. Side view of a cylindrical heater, FIG.
(E) is a plan view of the planar heater in that state.

In this embodiment, one of the primary side electrode patterns 3a, 3b which is in contact with the electrical contact 9 of the connector 8 is replaced with two kinds of abnormal metals 3a1, 3 having different coefficients of thermal expansion.
a2 is constituted by a pi-metal type opening / closing means bonded in a layered manner, and the primary electrode pattern 3a is convex in the direction of the electrical contact (FIG. 4) in order to reliably contact the electrical contact 9 of the connector 8. (B)). And
The surface of the primary electrode pattern 3a has an openable and closable insulating property that shuts off the primary electrode pattern 3a and the electrical contact 9 in the closed state and maintains the two electrodes 3a and 9 in the contact state in the open state. Body covers 15a and 15b are provided. The other configuration is the same as that of the first embodiment shown in FIG.
Therefore, the same portions are denoted by the same reference numerals, and redundant description will be omitted.

Next, the operation will be described.

During normal use, the insulator covers 15a, 15b
Is opened by being pushed by the primary electrode patterns 3a and 3b in the convex state, and the electrical contact 9 and the primary electrode pattern 3 are securely contacted and energized. Heating resistors 5a, 5
When b becomes a predetermined temperature or more (at abnormal temperature rise), the metal 3a1 having a high thermal expansion coefficient expands from the metal 3a2 having a low thermal expansion coefficient, and the shape of the primary-side electrode pattern 3a becomes convex in the direction of the electrical contact 9. From the state (FIG. 4B), the state is concave (FIG. 4B).
(D)), the primary electrode pattern 3
a and the electrical contacts 9 are in a non-contact state, and the insulator covers 15a and 15b are in a closed state, so that the power supply can be surely shut off urgently, and the heating resistors 5a and 5b
Abnormally high temperature can be stopped. In this case, by defining the shape (length and the like) of the insulator covers 15a and 15b, the creepage distance between the primary-side electrode pattern 3a and the electrical contact 9 can be secured in the closed state.

Further, after the emergency shutoff of the power supply, the heat generating resistors 5a and 5b recover to a predetermined temperature or lower, so that the metal 3a1 having a high thermal expansion coefficient of the primary side electrode pattern 3a becomes a metal having a low thermal expansion coefficient. 3a2, the primary side electrode pattern 3a operates from a concave state (FIG. 4 (d)) to a convex state (FIG. 4 (b)) in the direction of the electrical contact pattern, and the insulator cover 15a , 15b are in an open state, so that the temporary electrode pattern 3a and the electrical contact 9 are electrically connected to each other.
Returns to the contact state, and the power supply can be automatically restarted.

Embodiment 5 FIG. FIG. 5 is a cross-sectional view showing a fixing device 50 of the present invention to which the above-described heating device is applied.
In the figure, reference numeral 21 denotes a semicircular heater holder which accommodates and supports the planar heater 1 in a concave portion 21a on the surface, 22 denotes a cylindrical fixing film which is rotated and conveyed along the heater holder 21, and 23 denotes a fixing film 22 which has a planar shape. Total pressure 4 to heater 1
This is a pressure roller that pressurizes at about 15 kgf and forms a nip N between itself and the fixing film.
Is a roller 23 made of heat-resistant rubber having a central shaft 23a.
The protective layer 23c is provided on the surface of FIG.

The fixing film 22 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 25 having the unfixed toner image 24 formed on the surface thereof includes a pressing roller 23 which is rotated in the direction indicated by an arrow by a drive source (not shown) with the unfixed toner image 24 facing the fixing film 22. When the sheet is fed between the fixing film 22 and the passively rotating fixing film 22, the sheet is heated by the sheet heater 1 when passing through the nip while being sandwiched between the two 22 and 23, and the unfixed toner image 24 is melted and heated. It is fixed on the material 25.

Embodiment 6 FIG. FIG. 6 shows the fixing device 50 of FIG.
1 is a schematic diagram showing an image forming apparatus of the present invention to which the present invention is applied. In FIG. 6, reference numeral 31 denotes a photosensitive drum, which is an OPC,
A photosensitive material such as amorphous Se or amorphous Si is formed on a substrate on a cylinder such as aluminum or nickel.

The photosensitive drum 31 is driven to rotate in the direction of the arrow, and its surface is first uniformly charged by a charging roller 32 as a charging device. Next, scanning exposure is performed by a laser beam 33 that is ON / OFF controlled according to the image information, and an electrostatic latent image is formed. This electrostatic latent image is developed and visualized by the developing device 34. 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 visualized toner image 24 is transferred by a transfer roller 35 as a transfer device onto a transfer material 25 as a material to be heated, which is conveyed at a predetermined timing from a paper supply table 36 by a paper supply roller 37. The image is transferred from the photosensitive drum 31.
At this time, the transfer material 25 is nipped and conveyed between the photosensitive drum 1 and the transfer roller 35 with a constant pressing force. The transfer material 25 onto which the toner image 24 has been transferred is conveyed to the fixing device 50 shown in FIG. 5, and the toner image 24 is heated and melted and fixed on the transfer material 25 as a permanent image. As described above, the photosensitive drum 31, the charging roller 32, the laser beam 33, the developing device 34, and the transfer roller 35 form an image forming process unit.

On the other hand, the transfer residual toner remaining on the photosensitive drum 31 is removed from the photosensitive drum 31 by the cleaning device 37, and the photosensitive drum 31 is used for the next image formation.

[0049]

As described above, according to the present invention, the power supply path for the heating resistor is provided with the bimetallic opening / closing means in which two or more kinds of metals having different thermal expansions are formed in layers, so that abnormal A highly safe and easy-to-use heating device that can automatically shut off power supply to the heating resistor when the temperature rises and that can automatically restart power supply when the temperature drops to a predetermined value. There is an effect that can be obtained.

Further, an insulating cover which can be opened and closed is provided on the contact opening / closing side of the bimetallic opening / closing means.
Since the insulating cover is configured to be located between the contacts, the power supply can be more reliably cut off, and the safety can be further improved.

Further, by using the above-mentioned heating device as a heat source, it is possible to provide a highly safe fixing device capable of reliably fusing and fixing an unfixed toner image formed on a material to be heated to the material to be heated. effective.

Further, by applying the above fixing device, there is an effect that an image forming apparatus capable of performing high quality fixing can be provided.

[Brief description of the drawings]

FIG. 1 shows a planar heater 1 according to a first embodiment of the present invention.
Configuration diagram showing

FIG. 2 shows a planar heater 1 according to a second embodiment of the present invention.
Configuration diagram showing

FIG. 3 is a planar heater 1 according to a third embodiment of the present invention.
Configuration diagram showing

FIG. 4 shows a planar heater 1 according to a third embodiment of the present invention.
Configuration diagram showing

FIG. 5 is a schematic diagram showing a fixing device of the present invention to which the above-described heating device 50 is applied.

6 is a schematic diagram showing an image forming apparatus of the present invention to which the fixing device of FIG. 5 is applied.

FIG. 7 is a configuration diagram showing a conventional planar heater.

[Explanation of symbols]

1 planar heater, 2 planar substrate, 3 primary electrode patterns, 3a1, 3a2 two or more metals having different coefficients of thermal expansion,
5a, 5b Heating resistor, 8 connectors, 9 bimetallic opening / closing means, 9a, 9b Two or more metals having different coefficients of thermal expansion, 12a, 12b Power supply pattern, 23 Pressure roller (Pressing means), 24 Unfixed toner , 25 non-heating material, 31 photosensitive drum (image forming process means), 32
Charging roller (image forming process means), 33 laser beam (image forming process means), 34 developing device (image forming process means), 35 transfer roller (image forming process means).

Claims (7)

[Claims] 1. A heating apparatus comprising: a heating resistor having a heating resistor which generates heat by energization on a surface of a sheet substrate and a primary heater formed with a primary-side electrode pattern connected to the heating resistor and connected to a power supply connector. A heating device, wherein a bimetallic opening / closing means in which two or more kinds of metals having different coefficients of thermal expansion are formed in a layered manner is provided in a power supply path for the heating resistor. 2. The heating device according to claim 1, wherein the bimetallic opening / closing means is provided in the middle of a power supply pattern for the heating resistor. 3. The connector according to claim 1, wherein said bimetallic opening / closing means is provided at an electrical contact portion of said connector.
A heating device as described. 4. The heating device according to claim 1, wherein the bimetallic opening / closing means is provided on the primary electrode pattern. 5. The heating device according to claim 1, wherein the bimetallic switching device includes an insulating cover that can be opened and closed on a contact switching side. 6. A heating device according to claim 1, wherein a material to be heated having an unfixed toner image is brought into pressure contact with a sheet heater, and an unfixed toner image is formed on the material to be heated. And a heat-resistant pressurizing means for melting and fixing the toner. 7. An image comprising: an image forming process unit for forming an unfixed toner image on a material to be heated; and the fixing device according to claim 6, wherein the fixing device fuses and fixes the unfixed toner image on the material to be heated. Forming equipment.