JPH11344882A - Heating device, fixing device and image forming device provided with the fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and inexpensive heating device by eliminating the need for securing a distance between a heating element, which is a circuit at a primary side and a temperature detecting body that is a circuit at a secondary side. SOLUTION: A signal of a frequency corresponding to detected temperature information of a thermistor TH1 is outputted by a converting means 1a, an optical signal is converted into an electric pulse signal and is outputted after a photocoupler PC2 receives a signal from the converting means 1a and temporarily converts it into an optical signal and a control means 2a executes the changeover of a switching means 3a by receiving the electrical pulse signal from the photocoupler PC2 in this heating device, so that electric power from a commercial power source VAC to a heater H1 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device, a fixing device, and an image forming apparatus provided with the fixing device.

[0002]

2. Description of the Related Art FIG.
0 will be described.

In a conventional heating apparatus, as shown in FIG. 10, a primary-side heating pattern 101 as a heating element is provided on one surface of a ceramic plate 110 as a substrate mainly composed of ceramics. A chip thermistor 104 serving as a temperature detector is provided on the other surface of 110, and a primary-side heating pattern 101 is supplied with power from a power supply through a primary-side wire 108 from a primary-side electrode 102 via a primary-side connector 103 to generate heat. The chip thermistor 104 includes a secondary side pattern 106
Through the secondary connector 107 and the secondary wire 109
Is connected to a microcomputer or the like as control means provided outside.

[0004]

However, in such a heating device, the heat generating pattern 101 usually consumes a large amount of power, so that a commercial power supply is used as it is for driving, and the heat generating pattern 101 and the chip thermistor 104 are connected to the primary side. Therefore, a sufficient insulation distance is required between the heat generation pattern 101 and the chip thermistor 104 for user protection.

In such a heating device, since the circuits on the primary side and the circuit on the secondary side are mixed, the primary side electrode 102 on the ceramic plate 110 is connected to one end of the secondary side electrode 105 as shown in FIG. Has to be arranged at the other end, so that the degree of freedom of design is low and it is difficult to reduce the size.
02 and the secondary electrode 105, the ceramic plate 110 must be made larger in order to secure the distance between the primary electrode 102 and the secondary electrode 105. In order to ensure the withstand voltage with respect to the secondary side electric wire 109, it is necessary to make the coating thick, which leads to an increase in cost.

A primary electrode 102 and a secondary electrode 105
Ceramic plate 1 to ensure the safety standard distance between
Since the width of 10 cannot be reduced, it is difficult to reduce the size, and the ceramic material cannot be saved.

Accordingly, the present invention eliminates the need for providing a distance between a heating element, which is a primary circuit, and a temperature detector, which is a secondary circuit, and provides a small and inexpensive heating device, fixing device and fixing device. It is an object of the present invention to provide an image forming apparatus including:

[0008]

According to the present invention, there is provided a heating apparatus for a fixing device, wherein a temperature of a heating element which generates heat by receiving power from a power supply is detected by a temperature detecting element. A heating device comprising: a switching unit that can be switched between conduction from a power supply to a heating element and switching between the conduction and a cutoff thereof; and a control unit that switches the switching unit in accordance with a detected temperature of the temperature detector. A converter for outputting a signal having a frequency corresponding to the detected temperature information of the temperature detector; a signal received from the converter and converted once into an optical signal; and then the optical signal is converted into an electric pulse signal and output. This is achieved by the first invention having transmission means, wherein the control means switches the switching means in response to the electric pulse signal from the transmission means.

According to the present application, the above object is achieved according to the first aspect, wherein the heating element is provided on one surface of the substrate,
This is also achieved by the second invention in which the substrate contains ceramics as a main component.

Further, according to the present application, the above object is also achieved by the third invention in which, in the second invention, the temperature detector is provided on the other surface of the substrate.

According to the present application, the above object is achieved by any one of the first to third inventions, wherein the control means comprises:
This is also achieved by the fourth invention in which switching of the switching means is controlled in accordance with the pulse width of the electric pulse signal from the transmission means.

Further, according to the present application, the above object is achieved according to any one of the first to third inventions, wherein the control means controls the electric pulse signal from the transmission means in accordance with the number of pulses within a predetermined time. This is also achieved by the fifth invention in which switching of the switching means is controlled.

Further, according to the present application, the above object is achieved by any one of the first to third inventions, wherein the control means comprises:
The present invention is also achieved by the sixth invention in which after converting the voltage into a voltage corresponding to the electric pulse signal from the transmission unit, switching of the switching unit is controlled according to the voltage.

Further, according to the present application, the above object is to provide a fixing device for an image forming apparatus for fixing the unfixed image to the recording medium by applying heat and pressure to the recording medium carrying the unfixed image. The present invention is also achieved by a seventh invention in which the heating device of the first invention is provided.

Further, according to the present application, the above object is achieved according to the seventh aspect, wherein the heating element is provided on one surface of the substrate,
This is also achieved by the eighth invention in which the substrate contains ceramics as a main component.

Further, according to the present application, the above object is also achieved by the ninth invention in the eighth invention, wherein the temperature detector is provided on the other surface of the substrate.

Further, according to the present application, the above object is achieved by any one of the seventh to ninth inventions, wherein the control means comprises:
The present invention is also achieved by the tenth invention in which switching of the switching unit is controlled in accordance with the pulse width of the electric pulse signal from the transmission unit.

Further, according to the present application, the above object is achieved according to any one of the seventh to ninth inventions, wherein the control means controls the electric pulse signal from the transmission means in accordance with the number of pulses within a predetermined time. This is also achieved by the eleventh invention of controlling the switching of the switching means.

Further, according to the present application, the above object is achieved by any one of the seventh to ninth inventions, wherein the control means comprises:
The present invention is also achieved by a twelfth invention in which, after conversion into a voltage corresponding to the electric pulse signal from the transmission means, switching of the switching means is controlled in accordance with the voltage.

Further, according to the present application, an object of the present invention is to provide an image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, and comprising a fixing device according to a seventh aspect of the present invention. This is also achieved by the third invention.

Further, according to the present application, the above object is attained in the thirteenth invention, wherein the heating element is provided on one surface of the substrate, and the substrate is mainly composed of ceramics. Is also achieved by

Further, according to the present application, the above object is also attained by the fifteenth invention in which, in the fourteenth invention, the temperature detector is provided on the other surface of the substrate.

According to the present application, the above object is achieved in any one of the thirteenth invention to the fifteenth invention in that the control means comprises a switching means in accordance with a pulse width of the electric pulse signal from the transmission means. This is also achieved by the sixteenth invention of controlling the switching between the two.

Further, according to the present application, the above object is achieved in any one of the thirteenth invention to the fifteenth invention, wherein the control means controls the number of pulses of the electric pulse signal from the transmission means within a predetermined time. This is also achieved by a seventeenth invention in which the switching of the switching means is controlled accordingly.

According to the present application, the above object is achieved in any one of the thirteenth to fifteenth inventions, wherein the control means converts the voltage into a voltage corresponding to the electric pulse signal from the transmission means. The present invention is also achieved by an eighteenth invention in which switching of the switching means is controlled in accordance with the voltage.

That is, in the first invention according to the present application, the conversion means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmission means receives the signal from the conversion means and outputs the signal. Is temporarily converted into an optical signal, and then the optical signal is converted into an electric pulse signal and output. The control means receives the electric pulse signal from the transmitting means and switches the switching means, so that the power from the power source to the heating element is changed. Control.

According to the second aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means receives the electric pulse signal from the transmission means and switches the switching means, thereby making the substrate mainly composed of ceramics. The power from the power supply is controlled to the heating element provided above.

Further, in the third invention according to the present application, the conversion means outputs a signal having a frequency corresponding to detected temperature information of a temperature detector provided on a substrate mainly composed of ceramics, The transmission means receives the signal from the conversion means, converts the signal once into an optical signal, converts the optical signal into an electric pulse signal and outputs the signal, and the control means receives the electric pulse signal from the transmission means and switches the switching means. Is performed to control the power from the power supply to the heating element on the substrate.

In the fourth invention according to the present application, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is temporarily converted into an optical signal, the optical signal is converted into an electric pulse signal and output, and the control means switches the switching means according to the pulse width of the electric pulse signal from the transmission means, so that the heating element is To control the power to.

Further, in the fifth invention according to the present application, the converting means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means performs switching of the switching means according to the number of pulses of the electric pulse signal from the transmission means within a predetermined time. Controls the power from the power supply to the heating element.

According to the sixth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is once converted to an optical signal, the optical signal is converted to an electric pulse signal and output, and the control means converts the voltage to a voltage corresponding to the electric pulse signal from the transmitting means, and then switches the switching means according to the voltage. By doing so, the power from the power supply to the heating element is controlled.

Further, in the seventh invention according to the present application, the converting means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is temporarily converted into an optical signal, and then the optical signal is converted into an electric pulse signal and output. The control means receives the electric pulse signal from the transmitting means and switches the switching means, so that the power from the power source to the heating element is changed. Control.

According to the eighth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means receives the electric pulse signal from the transmission means and switches the switching means, thereby making the substrate mainly composed of ceramics. The power from the power supply is controlled to the heating element provided above.

Further, according to the ninth invention of the present application, the conversion means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector provided on the substrate mainly composed of ceramics, The transmission means receives the signal from the conversion means, converts the signal once into an optical signal, converts the optical signal into an electric pulse signal and outputs the signal, and the control means receives the electric pulse signal from the transmission means and switches the switching means. To control the power from the power supply to the heating element on the substrate.

According to the tenth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is temporarily converted into an optical signal, the optical signal is converted into an electric pulse signal and output, and the control means switches the switching means according to the pulse width of the electric pulse signal from the transmission means, so that the heating element is To control the power to.

Further, in the eleventh invention according to the present application, the conversion means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmission means receives the signal from the conversion means. This is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means switches the switching means according to the number of pulses of the electric pulse signal from the transmission means within a predetermined time. Control the power from the power supply to the heating element.

In the twelfth invention according to the present application, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means. Once this is converted into an optical signal, the optical signal is converted into an electric pulse signal and output, and the control means converts the voltage into a voltage corresponding to the electric pulse signal from the transmitting means, and then switches the switching means according to the voltage. To control the power from the power supply to the heating element.

Further, in the thirteenth invention according to the present application, the converting means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means. Once this is converted into an optical signal, the optical signal is converted into an electric pulse signal and output, and the control means receives the electric pulse signal from the transmitting means and switches the switching means. Control power.

In the fourteenth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means. This is once converted into an optical signal, and then the optical signal is converted into an electric pulse signal and output, and the control means receives the electric pulse signal from the transmission means and switches the switching means, so that the main component is ceramics. The power from the power supply is controlled to the heating element provided on the substrate.

Further, in the fifteenth invention according to the present application, the conversion means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector provided on the substrate mainly composed of ceramics. The transmission means receives the signal from the conversion means, converts the signal once into an optical signal, converts the optical signal into an electric pulse signal and outputs the signal, and the control means receives the electric pulse signal from the transmission means and controls the switching means. By switching,
The power from the power supply is controlled to the heating element on the substrate.

In the sixteenth invention according to the present application, the converting means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means. This is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means switches the switching means according to the pulse width of the electric pulse signal from the transmission means, thereby generating heat from the power supply. Controls power to the body.

Further, in the seventeenth invention according to the present application, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means. This is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means switches the switching means according to the number of pulses of the electric pulse signal from the transmission means within a predetermined time. Control the power from the power supply to the heating element.

According to the eighteenth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means. Once this is converted into an optical signal, the optical signal is converted into an electric pulse signal and output, and the control means converts the voltage into a voltage corresponding to the electric pulse signal from the transmitting means, and then switches the switching means according to the voltage. To control the power from the power supply to the heating element.

[0044]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG.

(First Embodiment) FIG. 1 is a schematic sectional view showing a schematic configuration of a laser beam printer 10 (hereinafter, referred to as a printer 10) as an example of an image forming apparatus according to a first embodiment of the present invention. is there.

As shown in FIG. 1, the printer 10 has a drum-shaped photosensitive member 12 on which an electrostatic latent image is formed on the outer peripheral surface, and a roller-shaped photosensitive member 12 for charging the outer peripheral surface of the photosensitive member 12 to a specified potential. A charging unit 13, a laser scanner unit 14 for forming an electrostatic latent image on the outer peripheral surface charged to a specified potential by exposure, a developing device 15 for visualizing the electrostatic latent image with a developer, The fixing device 17 includes a roller-shaped transfer body 16 that transfers a visible image (visible image) formed on the outer peripheral surface onto a recording sheet P as a sheet-shaped recording medium.

In the printer 10, first, the charged body 1
The laser scanner unit 14 exposes the outer peripheral surface of the photoreceptor 12 charged to the specified potential in 3 to form an electrostatic latent image on the outer peripheral surface according to image information given to the printer 10 from outside. Is done.

Next, the electrostatic latent image formed on the outer peripheral surface of the photosensitive member 12 is visualized into a visible image by applying a developer from the developing device 15.

On the other hand, the recording paper P on which image information corresponding to the given image information is recorded is placed on the cassette 18 detachably supported by the main body of the printer 10 or on one side of the printer 10. Multi paper tray 1
9 to a transfer nip TN formed between the photoconductor 12 and the transfer body 16 at a predetermined timing or the like.

Thus, the recording paper P which has reached the transfer nip TN is formed on the outer peripheral surface of the photoreceptor 12, and the carried visual image is transferred from the transfer body 16 by electric interaction.

Next, the recording paper P having the developed image carried on one surface in an unfixed state (hereinafter, the developed image in the unfixed state is referred to as an unfixed image) is supplied to the fixing device 17 by heat supply. When the pressure is applied, the unfixed image is melted and fixed, so that the recording paper P is recorded with an image corresponding to the given image information, and the formed recording paper P is Tray 2 arranged on the other side of the main body
0 is discharged.

FIG. 2 is a schematic sectional view showing a schematic configuration of the fixing device 17 in this embodiment.

The fixing unit 17 includes a heating unit 9 serving as a heating device,
A support 8 for fixing and supporting the heating unit 9, a heat-resistant film 6 externally fitted to the heating unit 9 and the support 8, and a rotating body pressurizing the heating unit 9 through the film 6. Roller 7
The film 6 is slid by the rotation of the pressure roller 7, and the recording paper P carrying the unfixed image is passed through the nip N by the pressure contact between the film 6 and the pressure roller 7. The unfixed image is fixed on the recording paper P by the heat of the heating unit 9 via the film 6.

FIG. 3 is a block diagram showing a signal path of a control system of the heating device according to the present embodiment.

The heating unit 9 includes a heater H1 serving as a heating element that generates heat by receiving electric power from a commercial power supply VAC serving as a power supply, and a thermistor TH1 serving as a temperature detector that detects the temperature of the heater H1.
And

The heater H1 is provided on one surface of a substrate mainly composed of ceramics, and the thermistor TH1 is provided on the other surface of the substrate.

The control unit 22 attached to the main body of the printer 10 having the heating unit 9 changes the
Switching means 3a which can be switched to either conduction to or disconnection from the switching element 1; control means 2a which switches the switching means 3a in accordance with the temperature detected by the thermistor TH1; It has a converting means 1a for outputting a signal, and a photocoupler PC2 as a transmitting means for receiving a signal from the converting means 1a, converting the optical signal once into an optical signal, converting the optical signal into an electric pulse signal and outputting the same. ing.

The control means 2a receives the electric pulse signal from the photocoupler PC2 and switches the switching means 3a.

As shown in FIG. 3, a commercial power supply VAC, a common mode choke coil 11, a diode bridge D
1, smoothing capacitor C1, transformer 12, FET Q1,
The control circuit CONT forms a switching power supply based on the output from the photocoupler PC1, and the regulation circuit REG converts the power rectified by the diode bridge D1 and the smoothing capacitor C1 into the primary power supply Vcc1.
Is output.

On the secondary side, the secondary power supply Vcc2 is output by the choke coil L3 and the capacitor C2 via the rectifier diodes D2 and D3, and the output of the secondary power supply Vcc2 is output to the photocoupler PC1 via the error amplifier AMP. A feedback loop is realized by a configuration in which the current value changes.

On the other hand, the commercial power supply VAC is
Electric power is supplied to the heater H <b> 1 provided in the heating unit 9 through the heater 3. The heater H1 has a thermistor TH1 disposed in the vicinity.

The triac Q3 is connected to the CPU 5 arranged on the secondary side via the phototriac SSR1.
To the transistor Q4 via the resistor R10,
In response to two types of signals Hi and Lo from the CPU 5, a current flows to the diode side of the phototriac SSR1 through the limiting resistor R8 to receive control.
The switching of conduction or interruption to 1 is controlled.

Next, IC4 is N for realizing an oscillation circuit.
When a circuit corresponding to NE555 is used as a circuit corresponding to E555, for example, the thermistor TH1 is connected to the IC4 to form an astable multivibrator 1a having an oscillation frequency f as shown in the following equation. Note that the resistance of the resistor R1 is R, the resistance of the thermistor TH1 is T, and the capacitance of the capacitor C3 is C.

F = 1.44 / ((R + 2T) × C) The output from the IC 4 is connected to the transistor Q2 via the resistors R2 and R3 and from the photocoupler PC2 connected to the collector via the current limiting resistor R4. Output to the secondary side.

A resistor R5 is connected between the power supply Vcc2 and the collector on the output side of the photocoupler PC2.
This output is input to the external interrupt terminal EXINT of the CPU to detect information from the primary side.

FIG. 4 is a graph showing the relationship between the signals detected by the conversion means and the control means with respect to the detected temperature information of the temperature detector provided in the heating device in this embodiment.

As shown in FIG. 4, the thermistor TH1
The resistance decreases as the temperature rises. The frequency of the astable multivibrator 1a decreases as the resistance of the thermistor TH1 increases. Therefore, the output frequency increases as the temperature rises.

The CPU 5 measures the time of the pulse width input to EXINT by detecting an interrupt, such as t1, t2, and t3, and determines that the temperature is high when the pulse width is large and low when the pulse width is small. And thermistor TH1
Is turned on / off for transistor Q4 such that
OFF control is performed.

Therefore, according to the present embodiment, the conversion means 1
a outputs a signal having a frequency corresponding to the detected temperature information of the thermistor TH1, and the photocoupler PC2 receives the signal from the conversion means 1a, converts the signal once into an optical signal, and then converts the optical signal into an electric pulse signal. The control means 2a is set so as to control the power from the commercial power supply VAC to the heater H1 by the control means 2a receiving the electric pulse signal from the photocoupler PC2 and switching the switching means 3a. By eliminating the relationship between the primary side and the secondary side with the thermistor TH1, the heater H1 and the thermistor TH are eliminated.
1 can be shortened, the degree of freedom in designing the heating unit 9 can be increased, and downsizing can be achieved.

According to the present embodiment, the distance between the heater H1 and the thermistor TH1 can be shortened.
Ceramics as a substrate can be made smaller, and a heating device can be configured at low cost.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

FIG. 5 is a graph showing a relationship between signals detected by the conversion means and the control means with respect to the detected temperature information of the temperature detector provided in the heating device in this embodiment.

As shown in FIG. 5, the thermistor TH1 is
The resistance decreases as the temperature rises. The frequency of the astable multivibrator 1a decreases as the resistance of the thermistor TH1 increases. Therefore, the output frequency increases as the temperature rises.

The CPU 5 counts the number of pulses input to EXINT at an arbitrarily determined period of t4 by interrupt detection, and determines that the temperature is high when the number of pulses is small and low when the number of pulses is large. And thermistor TH1
Is turned on / off for transistor Q4 such that
OFF control is performed.

Therefore, according to the present embodiment, the conversion means 1
a outputs a signal having a frequency corresponding to the detected temperature information of the thermistor TH1, and the photocoupler PC2 receives the signal from the conversion means 1a, converts the signal once into an optical signal, and then converts the optical signal into an electric pulse signal. The control means 2a is set so as to control the power from the commercial power supply VAC to the heater H1 by the control means 2a receiving the electric pulse signal from the photocoupler PC2 and switching the switching means 3a. By eliminating the relationship between the primary side and the secondary side with the thermistor TH1, the heater H1 and the thermistor TH are eliminated.
1 can be shortened, the degree of freedom in designing the heating unit 9 can be increased, and downsizing can be achieved.

According to the present embodiment, the distance between the heater H1 and the thermistor TH1 can be reduced.
Ceramics as a substrate can be made smaller, and a heating device can be configured at low cost.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

FIG. 6 is a block diagram showing a signal path of a control system of the heating device in the present embodiment.

As shown in FIG. 6, what differs from the first embodiment and the second embodiment is that the resistors R11 and R1
2 and capacitor C1, capacitor C2 and diode D1
0 and addition of A / D input of CPU5.

The Hi output from the photocoupler PC2 integrates the rising by the resistor R12 and the capacitor C10.
The Lo output is stored in a capacitor C11 via a diode D10, and the Lo output converts the output frequency of the astable multivibrator 1a on the primary side into a voltage by discharging the charge stored in the capacitor C11 via a resistor R11. And connected to the A / D input terminal of the CPU.

FIG. 7 is a graph showing a relation between signals detected by the conversion means and the control means with respect to the detected temperature information of the temperature detector provided in the heating device in the present embodiment.

As shown in FIG. 7, the thermistor TH1 is
The resistance decreases as the temperature rises. The frequency of the astable multivibrator 1a decreases as the resistance of the thermistor TH1 increases. Therefore, the output frequency increases as the temperature rises.

The CPU 5 converts the analog voltage input to the A / D into a digital signal and determines that the temperature is high when the conversion result data is small and low when the conversion result data is large. The ON / OFF control is performed on the transistor Q4 so that

Therefore, according to the present embodiment, the conversion means 1
a outputs a signal having a frequency corresponding to the detected temperature information of the thermistor TH1, and the photocoupler PC2 receives the signal from the conversion means 1a, converts the signal once into an optical signal, and then converts the optical signal into an electric pulse signal. The control means 2b is set to control the power from the commercial power supply VAC to the heater H1 by the control means 2b receiving the electric pulse signal from the photocoupler PC2 and switching the switching means 3a. By eliminating the relationship between the primary side and the secondary side with the thermistor TH1, the heater H1 and the thermistor TH are eliminated.
1 can be shortened, the degree of freedom in designing the heating unit 9 can be increased, and downsizing can be achieved.

According to the present embodiment, the distance between the heater H1 and the thermistor TH1 can be reduced.
Ceramics as a substrate can be made smaller, and a heating device can be configured at low cost.

[0086]

As described above, according to the first aspect of the present invention, the conversion means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector, and the transmission means converts the signal. By receiving the signal from the means and converting it into an optical signal once, converting the optical signal into an electric pulse signal and outputting it, the control means receives the electric pulse signal from the transmitting means and switches the switching means. Since the power from the power supply to the heating element is set to be controlled, the distance between the heating element and the temperature detecting element is reduced by eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detecting element. Therefore, the degree of freedom in design can be increased and downsizing can be achieved.

According to the second aspect of the present invention,
The converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means, converts the signal once into an optical signal, and then converts the optical signal into an electric pulse signal. Output, and the control means receives the electric pulse signal from the transmission means and performs switching of the switching means,
Since it is set to control the power from the power supply to the heating element provided on the substrate mainly composed of ceramics,
By eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detector, the distance between the heating element and the temperature detector can be shortened, so that the degree of freedom in design can be increased and the size can be reduced.

Further, according to the third invention of the present application, the conversion means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector provided on the substrate mainly composed of ceramics, and transmits the signal. The means receives the signal from the converting means, converts the signal once into an optical signal, converts the optical signal into an electric pulse signal and outputs the signal, and the control means receives the electric pulse signal from the transmitting means and switches the switching means. By doing so, it is set to control the power from the power supply to the heating element on the board, so by eliminating the relationship between the primary side and the secondary side between the heating element and the temperature detection element, the heating element and the temperature detection The distance from the body can be shortened, the degree of freedom in design increases, and downsizing can be achieved.

According to the fourth invention of the present application,
The converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means, converts the signal once into an optical signal, and then converts the optical signal into an electric pulse signal. The control means controls the power from the power supply to the heating element by switching the switching means according to the pulse width of the electric pulse signal from the transmission means. By eliminating the relationship between the primary side and the secondary side with the body, the distance between the heat generating body and the temperature detecting body can be shortened, so that the degree of freedom of design can be increased and the size can be reduced.

Further, according to the fifth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and converts the signal. Once converted into an optical signal, the optical signal is converted into an electric pulse signal and output, and the control means switches the switching means according to the number of pulses of the electric pulse signal from the transmission means within a predetermined time, thereby providing a power supply. Since it is set to control the power to the heating element, the distance between the heating element and the temperature sensing element can be shortened by eliminating the relationship between the primary side and the secondary side of the heating element and the temperature sensing element. Therefore, the degree of freedom of design can be increased and the size can be reduced.

Further, according to the sixth invention of the present application,
The converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means, converts the signal once into an optical signal, and then converts the optical signal into an electric pulse signal. Output, the control means converts the voltage into a voltage corresponding to the electric pulse signal from the transmission means, and then switches the switching means according to the voltage, so that the power from the power supply to the heating element is set to be controlled. The distance between the heating element and the temperature detector can be shortened by eliminating the relationship between the primary and secondary sides of the heating element and the temperature detector, thereby increasing the degree of design freedom and miniaturization. Can be.

Further, according to the seventh aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and converts the signal. Once converted into an optical signal, the optical signal is converted into an electric pulse signal and output, and the control means receives the electric pulse signal from the transmitting means and switches the switching means, thereby reducing the power from the power supply to the heating element. Since it is set to be controlled, the distance between the heating element and the temperature detector can be shortened by eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detector. Further downsizing can be achieved.

According to the eighth invention of the present application,
The converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means, converts the signal once into an optical signal, and then converts the optical signal into an electric pulse signal. Output, and the control means receives the electric pulse signal from the transmission means and performs switching of the switching means,
Since it is set to control the power from the power supply to the heating element provided on the substrate mainly composed of ceramics,
By eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detector, the distance between the heating element and the temperature detector can be shortened, so that the degree of freedom in design can be increased and the size can be reduced.

Further, according to the ninth invention of the present application, the conversion means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detecting member provided on the substrate mainly composed of ceramics, and transmits the signal. The means receives the signal from the converting means, converts the signal once into an optical signal, converts the optical signal into an electric pulse signal and outputs the signal, and the control means receives the electric pulse signal from the transmitting means and switches the switching means. By doing so, it is set to control the power from the power supply to the heating element on the board, so by eliminating the relationship between the primary side and the secondary side between the heating element and the temperature detection element, the heating element and the temperature detection The distance from the body can be shortened, the degree of freedom in design increases, and downsizing can be achieved.

According to the tenth aspect of the present invention,
The converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means, converts the signal once into an optical signal, and then converts the optical signal into an electric pulse signal. The control means controls the power from the power supply to the heating element by switching the switching means according to the pulse width of the electric pulse signal from the transmission means. By eliminating the relationship between the primary side and the secondary side with the body, the distance between the heat generating body and the temperature detecting body can be shortened, so that the degree of freedom of design can be increased and the size can be reduced.

Further, according to the eleventh aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means performs switching of the switching means according to the number of pulses of the electric pulse signal from the transmission means within a predetermined time. Since it is set to control the power from the power supply to the heating element, the distance between the heating element and the temperature detection element can be shortened by eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detection element. Therefore, the degree of freedom of design is increased, and downsizing can be achieved.

According to the twelfth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is once converted to an optical signal, the optical signal is converted to an electric pulse signal and output, and the control means converts the voltage to a voltage corresponding to the electric pulse signal from the transmitting means, and then switches the switching means according to the voltage. By doing so, it is set to control the power from the power supply to the heating element, so by eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detection element, the distance between the heating element and the temperature detection element Can be shortened, the degree of freedom of design increases, and downsizing can be achieved.

Further, according to the thirteenth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is temporarily converted into an optical signal, and then the optical signal is converted into an electric pulse signal and output. The control means receives the electric pulse signal from the transmitting means and switches the switching means, so that the power from the power source to the heating element is changed. The distance between the heating element and the temperature detector can be reduced by eliminating the relationship between the primary and secondary sides of the heating element and the temperature detector. And the size can be reduced.

According to the fourteenth aspect of the present invention, the converting means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means receives the electric pulse signal from the transmission means and switches the switching means, thereby making the substrate mainly composed of ceramics. Since it is set to control the power from the power supply to the heating element provided above, by eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detector, the connection between the heating element and the temperature detector is eliminated. The distance can be shortened, the degree of freedom in design increases, and downsizing can be achieved.

Further, according to the fifteenth invention of the present application, the conversion means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector provided on the substrate mainly composed of ceramics, The transmission means receives the signal from the conversion means, converts the signal once into an optical signal, converts the optical signal into an electric pulse signal and outputs the signal, and the control means receives the electric pulse signal from the transmission means and switches the switching means. Is performed so as to control the power from the power supply to the heating element on the substrate, so that the relationship between the heating element and the temperature detection element on the primary side and the secondary side is eliminated, so that the heating element and the temperature The distance from the detection object can be shortened, the degree of freedom in design increases, and downsizing can be achieved.

According to the sixteenth aspect of the present invention, the converting means outputs a signal of a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is temporarily converted into an optical signal, the optical signal is converted into an electric pulse signal and output, and the control means switches the switching means according to the pulse width of the electric pulse signal from the transmission means, so that the heating element is Power is controlled so that the distance between the heating element and the temperature detector can be shortened by eliminating the relationship between the primary and secondary sides of the heating element and the temperature detector. And the size can be reduced.

Further, according to the seventeenth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is converted into an optical signal once, the optical signal is converted into an electric pulse signal and output, and the control means performs switching of the switching means according to the number of pulses of the electric pulse signal from the transmission means within a predetermined time. Since it is set to control the power from the power supply to the heating element, the distance between the heating element and the temperature detection element can be shortened by eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detection element. Therefore, the degree of freedom of design is increased, and downsizing can be achieved.

According to the eighteenth aspect of the present invention, the converting means outputs a signal having a frequency corresponding to the detected temperature information of the temperature detector, and the transmitting means receives the signal from the converting means and outputs the signal. Is once converted to an optical signal, the optical signal is converted to an electric pulse signal and output, and the control means converts the voltage to a voltage corresponding to the electric pulse signal from the transmitting means, and then switches the switching means according to the voltage. By doing so, it is set to control the power from the power supply to the heating element, so by eliminating the relationship between the primary side and the secondary side of the heating element and the temperature detection element, the distance between the heating element and the temperature detection element Can be shortened, the degree of freedom of design increases, and downsizing can be achieved.

[Brief description of the drawings]

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

FIG. 2 is a schematic cross-sectional view illustrating a schematic configuration of a fixing device provided in the image forming apparatus of FIG.

FIG. 3 is a block diagram illustrating a configuration of a heating device provided in the fixing device of FIG. 2;

FIG. 4 is a graph showing a relationship between a signal and detected temperature information of a temperature detector in the heating device of FIG. 2;

FIG. 5 is a graph showing a relationship between signals and detected temperature information of a temperature detector in the heating device according to the second embodiment.

FIG. 6 is a block diagram illustrating a configuration of a heating device according to a third embodiment.

FIG. 7 is a graph showing a relationship between a signal and detected temperature information of a temperature detector in the heating device of FIG. 6;

FIG. 8 is a schematic diagram illustrating a relationship between a heating element and a temperature detector in a conventional heating device.

[Explanation of symbols]

 VAC Commercial power supply (power supply) TH1 Thermistor (temperature detector) H1 Heater (heating element) CPU control means PC2 Photocoupler (transmission means) P Recording paper (recording medium) 1a Conversion means 2a Control means 2b Control means 9 Heating device 17 Fixing Apparatus 10 Image forming apparatus

Claims (18)

[Claims] 1. A heating device for a fixing device, wherein a temperature of a heat generating element that generates heat by receiving power from a power supply is detected by a temperature detecting element, wherein conduction from the power supply to the heat generating element and cutoff thereof are provided. A switching device that can be switched to any one of the above, and a control device that performs switching of the switching device in accordance with the detected temperature of the temperature detector, a signal having a frequency corresponding to the detected temperature information of the temperature detector. Conversion means for outputting, and a transmission means for receiving a signal from the conversion means, temporarily converting the signal into an optical signal, and then converting the optical signal into an electric pulse signal and outputting the signal, and wherein the control means controls the transmission from the transmission means. A heating device for switching a switching unit in response to an electric pulse signal. 2. A heating element is provided on one surface of the substrate,
The heating device according to claim 1, wherein the substrate is mainly composed of ceramics. 3. The heating device according to claim 2, wherein the temperature detector is provided on the other surface of the substrate. 4. The heating apparatus according to claim 1, wherein the control means controls switching of the switching means according to a pulse width of the electric pulse signal from the transmission means. 5. The control unit according to claim 1, wherein the control unit controls switching of the switching unit according to the number of pulses of the electric pulse signal from the transmission unit within a predetermined time. Heating equipment. 6. The control unit according to claim 1, wherein the control unit converts the voltage into a voltage corresponding to the electric pulse signal from the transmission unit, and then controls the switching of the switching unit according to the voltage. The heating device according to claim 1. 7. A fixing device for an image forming apparatus for fixing the unfixed image on the recording medium by applying heat and pressure to the recording medium carrying the unfixed image, according to claim 1, wherein Fixing device provided with a heating device. 8. The heating element is provided on one surface of the substrate,
The heating device according to claim 7, wherein the substrate contains ceramics as a main component. 9. The heating device according to claim 8, wherein the temperature detector is provided on the other surface of the substrate. 10. The heating apparatus according to claim 7, wherein the control means controls switching of the switching means according to a pulse width of the electric pulse signal from the transmission means. 11. The control unit according to claim 7, wherein the control unit controls the switching of the switching unit in accordance with the number of pulses of the electric pulse signal from the transmission unit within a predetermined time. Heating equipment. 12. The control unit according to claim 7, wherein the control unit converts the voltage into a voltage corresponding to the electric pulse signal from the transmission unit, and then controls switching of the switching unit according to the voltage. The heating device according to claim 1. 13. An image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, comprising the fixing device according to claim 7. 14. The heating device according to claim 13, wherein the heating element is provided on one surface of the substrate, and the substrate contains ceramic as a main component. 15. The heating device according to claim 14, wherein the temperature detector is provided on the other surface of the substrate. 16. The heating apparatus according to claim 13, wherein the control unit controls switching of the switching unit according to a pulse width of the electric pulse signal from the transmission unit. 17. The control unit according to claim 13, wherein the control unit controls switching of the switching unit in accordance with the number of pulses of the electric pulse signal from the transmission unit within a predetermined time. Heating equipment. 18. The control unit according to claim 13, wherein the control unit converts the voltage into a voltage corresponding to the electric pulse signal from the transmission unit, and controls switching of the switching unit according to the voltage. The heating device according to claim 1.