JPH1039671A - Heat roller fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the scratch and abrasion of a fixing roller by a temperature detecting means, by forming a fixing roller heating means and a pressure roller heating means as the heating means generating the same output, and providing the fixing roller with the construction same as that of the pressure roller. SOLUTION: The heat sources 3, 4 of a fixing roller heating means and a pressure roller heating means generate the same output to the same power supply. A fixing roller 1 has a mold releasing layer on a core metal layer, and has the construction almost same as that of a pressure roller 2, and the mold releasing layer has the thickness enough for setting the surface temperature of the fixing roller 1 at the prescribed value, to the surface temperature of the pressure roller 2. As a temperature detecting means for controlling the surface temperature of the fixing roller 1 and that of the pressure roller 2 at the prescribed value, a thermistor 5 kept into contact with the pressure roller, is installed. Thereby the surface temperature of the pressure roller 2 is detected, and the scratch and the abrasion of the fixing roller caused by the contact with the temperature detecting means, can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer,
The present invention relates to a heat roller fixing device used for an image forming apparatus such as a facsimile.

[0002]

2. Description of the Related Art Image forming apparatuses such as copiers, printers, and facsimile machines fix a toner image on a sheet such as paper to a sheet by a fixing device such as a heat roller fixing device. When the image forming apparatus is a color image forming apparatus such as a color copying machine, a color printer, and a color facsimile, a color toner image on a sheet such as paper is heated and pressed by a fixing roller and a pressure roller as a fixing device. A color fixing device for fixing a sheet is used.

A heat roller fixing device includes a fixing roller and a pressure roller which are rotatably arranged in pressure contact with each other, and a fixing roller heating means and a pressure roller heating means provided inside the fixing roller and the pressure roller, respectively. Means, a temperature detecting means comprising a thermistor which comes into contact with the fixing roller to detect the surface temperature thereof, and a fixing roller heating means and a pressure roller heating means which are driven by the detection signal of the temperature detecting means. Some include temperature control means for simultaneously controlling the surface temperature of the roller to a predetermined temperature.

The fixing roller and the pressure roller are heated by the fixing roller heating means and the pressure roller heating means, respectively, and the surface temperature of the fixing roller is detected by the temperature detecting means. The temperature control means controls the fixing roller heating means and the pressure roller heating means simultaneously based on the temperature detected by the temperature detection means so that the surface temperature of the fixing roller and the surface temperature of the pressure roller become a predetermined temperature. The pressure roller is driven to rotate by a driving source, and when the sheet such as paper passes through the nip portion of the fixing roller and the pressure roller, the toner image on the sheet is fixed to the sheet by heating and pressing by the fixing roller and the pressure roller. Let it.

Japanese Patent Application Laid-Open No. 4-289889 discloses a temperature sensor in a heat roller fixing device in which a temperature sensor as a temperature detecting means is brought into contact with an end of a fixing roller outside a paper passing area (an area where a sheet does not pass). Describes that the surface temperature of the fixing roller is detected to prevent the occurrence of contact flaws caused by the temperature sensor of the fixing roller on the image surface (the surface where the toner image of the sheet contacts).

Japanese Patent Application Laid-Open No. 63-259586 discloses a heat roller fixing device in which a temperature sensor is brought into contact with a pressure roller to detect a surface temperature of the pressure roller by the temperature sensor, and a detection signal of the temperature sensor is detected. The fixing roller heating means and the pressure roller heating means are simultaneously controlled by the temperature control means, the heat resistance of the fixing roller is made larger than that of the pressure roller, the surface temperature of the fixing roller is made lower than the surface temperature of the pressure roller, Describes a method of increasing the amount of heat applied to the sheet from the back side to prevent offset.

Japanese Patent Application Laid-Open No. 7-271238 discloses that in a heat roller fixing device, a temperature sensor is brought into contact with a pressure roller to detect the surface temperature of the pressure roller by the temperature sensor, and the detection signal of this temperature sensor is used. The temperature control means simultaneously controls the fixing roller heating means and the pressure roller heating means, and the temperature control means controls the energizing time to the fixing roller heating means and the pressure roller heating means to thereby control the surface temperature of the fixing roller and the pressure. Patent Document 1 discloses a device in which the surface temperature of a roller is controlled.

[0008]

In the above-described heat roller fixing device, the thermistor is brought into contact with the fixing roller to detect the surface temperature of the fixing roller. Grease and abrasion due to contact of the thermistor with the roller are one of the causes of shortening the life of the fixing roller. SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat roller fixing device capable of preventing a flaw and wear caused by contact of a fixing roller with a temperature detecting means.

[0009]

In order to achieve the above object, the present invention is directed to a fixing roller and a pressure roller which are pressed against each other and are rotatably arranged, and the fixing roller and the pressure roller. Fixing roller heating means and pressure roller heating means provided inside the pressure roller, temperature detecting means for detecting the surface temperature of the pressure roller, and the fixing roller heating means and the heating means based on a detection signal of the temperature detecting means. A heat roller fixing device for controlling the pressure roller heating means to simultaneously control the surface temperature of the fixing roller and the surface temperature of the pressure roller to predetermined temperatures. The pressure roller heating means comprises a heating means that outputs the same output, and the fixing roller has substantially the same configuration as the pressure roller, and has a surface temperature of the pressure roller. The surface temperature of the fixing roller for is one having a release layer of such a thickness to a predetermined temperature, formic's by the temperature sensing means contacts the fixing roller, it is possible to prevent wear.

According to a second aspect of the present invention, there is provided a fixing roller and a pressure roller which are rotatably arranged in pressure contact with each other, and a fixing roller heating means and a heating roller provided inside the fixing roller and the pressure roller, respectively. Pressure roller heating means, temperature detection means for detecting the surface temperature of the pressure roller, and the fixing roller heating means and the pressure roller heating means by means of a detection signal of the temperature detection means, the surface temperature of the fixing roller and the A heat roller fixing device having a temperature control means for simultaneously controlling a surface temperature of the pressure roller to be a predetermined temperature, wherein the fixing roller and the pressure roller are composed of rollers having substantially the same structure, The heating means comprises heating means for outputting an output such that the surface temperature of the fixing roller becomes a predetermined temperature with respect to the surface temperature of the pressure roller. There, formic's by the temperature sensing means contacts the fixing roller, the wear can be prevented.

According to a third aspect of the present invention, there is provided a fixing roller and a pressure roller which are rotatably arranged in pressure contact with each other, and a fixing roller heating means and a heating roller provided inside the fixing roller and the pressure roller, respectively. Pressure roller heating means, temperature detection means for detecting the surface temperature of the pressure roller, and the fixing roller heating means and the pressure roller heating means by means of a detection signal of the temperature detection means, the surface temperature of the fixing roller and the A heat roller fixing device having a temperature control means for simultaneously controlling the surface temperature of the pressure roller so as to be a predetermined temperature, wherein the fixing roller heating means and the pressure roller heating means comprise heating means for outputting the same output. ,
The fixing roller and the pressure roller are composed of rollers having substantially the same configuration and size, and can prevent flaws and wear due to contact of the fixing roller with temperature detecting means.

[0012]

FIG. 1 shows an embodiment of the invention according to claim 1, and FIG. 2 shows a circuit configuration of this embodiment.
This embodiment is an embodiment of a color fixing device used in a color image forming apparatus, and has a tubular fixing roller 1 and a tubular pressure roller 2 which are pressed against each other by a pressing means (not shown) and rotatably arranged. A heat source 3 including a heater as a fixing roller heating unit for heating the fixing roller 1 is disposed inside the fixing roller 1.
A heat source 4 composed of a heater as heating means for heating the pressure roller 2 for heating the pressure roller 2 is disposed in the inside.

The surface temperature of the fixing roller 1 and the pressure roller 2
As the temperature detecting means for controlling the surface temperature of the fixing roller 1 to a predetermined temperature, a flaw caused by contact of the fixing roller 1 with the temperature detecting means,
A thermistor 5 is provided in contact with the pressure roller 2 to prevent abrasion, and the thermistor 5 detects the surface temperature of the pressure roller 2.

The heat sources 3 and 4 are connected to an AC power supply AC via a solid state relay (SSR) 6 as a switch element.
, And generates heat when AC power is supplied from an AC power supply AC via the SSR 6 to the fixing roller 1.
Then, the pressure roller 2 is heated. In this case, the surfaces of the fixing roller 1 and the pressure roller 2 are
Of the fixing roller 1 and the pressure roller 2.

A temperature control circuit 7 as a temperature control means turns on / off the SSR 6 based on a temperature detection signal from the thermistor 5, so that the power supplied from the AC power supply AC to the heat source 4 is changed to the surface temperature of the pressure roller 2. At the same time, the power supplied from the AC power supply AC to the heat source 3 is controlled so that the surface temperature of the fixing roller 1 becomes a predetermined temperature. The fixing roller 1 and the pressure roller 2 are driven to rotate by a driving source (not shown). When a sheet such as paper passes through a nip portion between the fixing roller 1 and the pressure roller 2, the toner image on the sheet is applied to the fixing roller 1 and the heating roller. Pressure roller 2
Is fixed on the sheet by heating and pressing.

As the heat sources 3 and 4, heat sources that output the same output for the same supply power are used. As shown in FIG. 3, the fixing roller 1 has a release layer 1 b formed on a core metal layer 1 a, and the release roller 1 b has substantially the same structure as the pressure roller 2, and the release layer 1 b has a surface temperature of the pressure roller 2. Has a thickness such that the surface temperature of the fixing roller 1 becomes a predetermined temperature. The pressure roller 2 is also formed by forming a release layer on the core metal layer.

The heat roller fixing device of this embodiment will be described with reference to a model diagram as shown in FIG.
And when the surface temperature of the pressure roller 2 is controlled to a predetermined temperature by the temperature control circuit 7, it is considered to be in a steady state,
Assuming that the required heat amount of the heat source 3 is Q at that time, the following steady heat conduction equation of the circular tube is given by: Q = 2πr × 1 × λ × dt / dr r: radius of the circular tube, l: length of the circular tube, λ: From the thermal conductivity of the circular tube, the relationship between the heat quantity Q and the surface temperature T ₀ of the fixing roller 1 is as follows: T ₀ = T ₁ + Q / 2πλ ₁ × lnD ₀ / D ₁ T ₁ : the core metal layer 1 a and the release layer Temperature at the boundary with 1b, T ₂ : temperature of the inner diameter of the core metal layer 1a, λ ₁ : thermal conductivity of the release layer 1b,
λ ₂ : thermal conductivity of the core metal layer 1 a, D ₀ : outer diameter of the release layer 1 b,
D _{1 is} the outer diameter of the core layer 1a, and D _{2 is} the inner diameter of the core layer 1a.

From this relationship, the surface temperature T of the fixing roller 1
₀ quantity Q supplied from the heat source 3, the thermal conductivity lambda ₁ and the thickness of the release layer 1b, and the thermal conductivity lambda ₂ and the thickness of the core layer 1a is concerned, when designing a heat roller fixing device If the heat roller fixing device is optimized by combining these control factors, the object of the present invention can be achieved.

That is, the temperature control circuit 7 controls the heat source 4 so that the surface temperature of the pressure roller 2 becomes a predetermined temperature by turning on / off the SSR 6 based on the temperature detection signal from the thermistor 5. At the same time, the heat source 3 is controlled so that the surface temperature of the fixing roller 1 becomes a predetermined temperature by turning on / off the SSR 6 based on the temperature detection signal from the thermistor 5 at the same time.

For this reason, the heat quantity Q supplied to the heat sources 3 and 4, which is a control condition mainly related to the heat radiation of the heat sources 3 and 4 and the heat conduction of the rollers 1 and 2, which is derived from the above equation,
Heat transfer conditions of the rollers 1 and 2 (the core metal layer 1a and the release layer 1b
By optimizing the thermal conductivity λ ₁ , λ ₂ and the thickness D ₀ / D ₁ , the object of the present invention can be basically achieved. However, finding the optimum configuration by varying these conditions is a problem that is difficult to realize.

In this embodiment, the point at which the object of the present invention is easily achieved will be described using a model shown in FIG. The heater 3 built in the fixing roller 1 is turned on / off by the SSR 6 at the same timing as the turning on / off of the heater 4 built in the pressure roller 2 set at a predetermined temperature. At this time, mainly from the inside of the fixing roller 1 by the radiation heat of the heater 3, the core metal layer 1a and the release layer 1
Assuming that the amount of heat passing through b is Q, considering the above equation, the thermal conductivity of the core metal layer 1a made of aluminum (5
When the thermal conductivity λ ₂ of the core metal layer 1a is large, such as (× 10 minus 1 / cal / cm · sec · ° C.), the difference between T ₁ and T ₂ is very small.

[0022] The thermal conductivity thermal conductivity lambda ₁ is made of silicon or Teflon release layer 1b λ ₁ (5~6 × 10 -4
(Cal / cm · sec · ° C.), the temperature gradient of the release layer 1 b increases, and the surface temperature T ₀ of the fixing roller 1 depends on the thickness of the release layer 1 b and the amount of heat Q supplied from the heater 3. Is done. Therefore, the fixing roller 1 and the pressure roller 2 have the same other conditions except for the thickness of the release layer, that is, the fixing roller 1 and the pressure roller 2 have the same structure (material, thickness, and thickness of the core metal layer). The material (the material of the release layer) is the same, and the outputs (the number of watts) of the heaters 3 and 4 incorporated in the fixing roller 1 and the pressure roller 2 are made the same, and only the thickness of the release layer is appropriately selected. Thus, a desired surface temperature of the fixing roller 1 can be obtained with respect to a surface temperature of the pressure roller 2. In FIG. 4, T ₂₀ , λ ₁₀ , λ ₂₀ , D ₀₀ , D ₁₀ , and D ₂₀ are the core metal layers of the fixing roller 1 and the pressure roller 2 having the same configuration except for the thickness of the release layer. Temperature of inner diameter of 1a, release layer 1b
, The thermal conductivity of the core layer 1a, the outer diameter of the release layer 1b, the outer diameter of the core layer 1a, and the inner diameter of the core layer 1a. T ₀₀ and T ₀₀ ′ are the surface temperatures of the fixing roller 1 set by the thickness of the release layer, and T ₀₀ is the outer diameter of the release layer 1 b of D _00.
, T ₀₀ ′ indicates the surface temperature of the fixing roller 1 when the outer diameter of the release layer 1 b is D ₀₀ ′.

In this embodiment, for example, the heaters 3, 4
When the output (number of watts) = 640 W, the inner and outer diameters of the aluminum core layer 1a are 30φ and 40φ, the material of the release layer 1b is Teflon, and the thickness of the release layer 1b is 15 μm, the fixing roller 1 of the surface temperature T ₀ is 197 ° C., T ₀ is when a 45μm thickness of the release layer 1b is 194
C., and when the thickness of the release layer 1b is 500 μm, T ₀
Is 154 ° C., and T ₀ can be set to a desired fixing temperature by appropriately selecting the thickness of the release layer 1b.

Further, another embodiment of the invention according to claim 1 is that in the above embodiment, the heaters 3 and 4 are not connected in series but connected in parallel as shown in FIG.
The same effect as the above embodiment can be obtained.

As described above, according to the first embodiment of the present invention, the fixing roller 1 and the pressure roller 2 which are rotatably disposed while being pressed against each other, and the inside of the fixing roller 1 and the pressure roller 2 are provided. And heaters 3 and 4 provided as fixing roller heating means and pressure roller heating means, respectively, a thermistor 5 serving as a temperature detecting means for detecting the surface temperature of the pressure roller 2, and detection of the temperature detecting means 5. Temperature as temperature control means for simultaneously controlling the fixing roller heating means 3 and the pressure roller heating means 4 so that the surface temperature of the fixing roller 1 and the surface temperature of the pressure roller 2 become predetermined temperatures by a signal. In the heat roller fixing device having the control circuit 7, the fixing roller heating means 3 and the pressure roller heating means 4 comprise a heating means which outputs the same output, and The roller 1 has a release layer 1 b having a thickness substantially equal to that of the pressure roller 2 and having a predetermined surface temperature with respect to the surface temperature of the pressure roller 2. Therefore, it is possible to prevent a flaw and abrasion due to the contact of the fixing roller with the temperature detecting means, and it is relatively easy to realize without adding cost.

The second embodiment of the present invention easily achieves the object of the present invention by means different from the above-described first embodiment of the present invention. In the embodiment of the present invention according to claim 2, in the embodiment of the invention according to claim 1, the heater 3 incorporated in the fixing roller 1 is:
At the same timing as turning on / off the heater 4 built in the pressure roller 2 set at a predetermined temperature, the SSR 6
Is turned on / off.

At this time, the amount of heat that passes through the core metal layer 1a and the release layer 1b from the inside of the fixing roller 1 due to the radiant heat of the heater 3 becomes as the above-described basic formula, and the fixing roller 1 and the pressure roller 2 are constituted. (Material of core metal layer, thickness and material of release layer) are the same, and fixing roller 1 and pressure roller 2
By appropriately selecting the output (the number of watts) of the heaters 3 and 4 incorporated therein, a desired surface temperature of the fixing roller 1 with respect to the surface temperature of the pressure roller 2 can be obtained.

For example, as shown in FIG. 6, when the output of the heater 3 in the fixing roller 1 is increased, the radiant heat of the heater 3 is increased and the temperature in the tube of the fixing roller 1 is changed from T ₂ to T ₂ ′.
To the core metal layer 1a from the inside of the fixing roller 1.
And the amount of heat passing through the release layer 1b increases from Q to Q ′ (> Q), and the temperature at the boundary between the core metal layer 1a and the release layer 1b becomes T _1.
'Rises to the surface temperature of the fixing roller 1 is T ₀ from T _0' T ₁ from rising to.

[0029] At this time, the metal core layer 1a is a temperature gradient from the thermal conductivity lambda ₂ is small becomes small, the release layer 1b is the temperature gradient becomes large since a large thermal conductivity lambda _1. Conversely, if the output of the heater 3 in the fixing roller 1 is reduced, the radiant heat of the heater 3 is reduced and the fixing roller 1
, The amount of heat passing through the core metal layer 1a and the release layer 1b from inside the fixing roller 1 decreases, and the surface temperature of the fixing roller 1 decreases. That is, if the outputs (the number of watts) of the heaters 3 and 4 are appropriately selected, a desired surface temperature of the fixing roller 1 with respect to a surface temperature of the pressure roller 2 can be obtained.

As described above, according to the second embodiment of the present invention, the fixing roller 1 and the pressure roller 2 which are rotatably disposed while being pressed against each other, and the inside of the fixing roller 1 and the pressure roller 2 are provided. And heaters 3 and 4 provided as fixing roller heating means and pressure roller heating means, respectively, a thermistor 5 serving as a temperature detecting means for detecting the surface temperature of the pressure roller 2, and detection of the temperature detecting means 5. Temperature as temperature control means for simultaneously controlling the fixing roller heating means 3 and the pressure roller heating means 4 so that the surface temperature of the fixing roller 1 and the surface temperature of the pressure roller 2 become predetermined temperatures by a signal. In the heat roller fixing device having the control circuit 7, the fixing roller 1 and the pressure roller 2 are composed of rollers having substantially the same configuration, and the fixing roller heating unit 3 is Since the heating means outputs an output such that the surface temperature of the fixing roller 1 becomes a predetermined temperature with respect to the surface temperature of the pressure roller 2, scratches and abrasion caused by contact with the temperature detecting means of the fixing roller are prevented. And can be realized relatively easily at no cost.

The third embodiment of the present invention is different from the first embodiment of the present invention in that FIG.
As shown in (b), the fixing roller 1 and the pressure roller 2 are made substantially the same (the configuration and the size are the same), and the output (W number) of the heater 3 in the fixing roller 1 and the heater 4 in the pressure roller 2 Are the same, and a predetermined fixing temperature should be obtained as the surface temperature of the fixing roller 1. However, in this case, the surface temperature of the fixing roller 1 and the surface temperature of the pressure roller 2 are the same. The pressure roller 2 includes a core metal layer 2a and a release layer 2b similar to the core metal layer 1a and the release layer 1b of the fixing roller 1. In FIG. 7, T ₂₀ and T ₂₁ are fixing rollers 1.
And the temperature of the inner diameter of the core layers 1a, 2a in the pressure roller 2, λ ₂₀ , λ ₂₁ are the thermal conductivity of the core layers 1a, 2a, λ ₁₀ ,
λ ₁₁ is the release layer 1 b of the fixing roller 1 and the pressure roller 2,
b, the thermal conductivity, D ₀₀ , D ₀₁ are the outer diameters of the release layers 1b, 2b,
D _10, D ₁₁ is the core metal layer 1a, the outside diameter of 2a, D _20, D ₂₁ denotes the inner diameter of the metal core layer 1a, 2a.

This embodiment is the most realized among the ones in which the thermistor 5 is disposed on the pressure roller 2 side and the surface temperature of the fixing roller 1 and the surface temperature of the pressure roller 2 are simultaneously controlled by the temperature control circuit 7. It is easy to start up, and it is possible to reliably and stably control the temperature during the waiting period and during the sheet passing, thereby providing an effect that stable fixing performance can be obtained.

As described above, according to the third embodiment of the present invention, the fixing roller 1 and the pressure roller 2 which are pressed against each other and are rotatably arranged, and the inside of the fixing roller 1 and the pressure roller 2 And heaters 3 and 4 provided as fixing roller heating means and pressure roller heating means, respectively, a thermistor 5 serving as a temperature detecting means for detecting the surface temperature of the pressure roller 2, and detection of the temperature detecting means 5. Temperature as temperature control means for simultaneously controlling the fixing roller heating means 3 and the pressure roller heating means 4 so that the surface temperature of the fixing roller 1 and the surface temperature of the pressure roller 2 become predetermined temperatures by a signal. In the heat roller fixing device having the control circuit 7, the fixing roller heating means 3 and the pressure roller heating means 4 comprise a heating means which outputs the same output, and The heat roller according to claim 1, wherein the roller (1) and the pressure roller (2) are formed of rollers having substantially the same configuration and size. Stable temperature control is possible as compared with the roller fixing device, whereby stable fixing performance is obtained.

Next, a supplementary explanation will be added to each embodiment of the first and second aspects of the present invention based on experimental examples. In each of the embodiments of the present invention according to the first and second aspects of the present invention, a roller having a diameter of 30 mm and a release layer 1b made of Teflon is used as the fixing roller 1, and a pressure roller 2 having a thickness of 30 mm and a release layer 1b made of silicon rubber. When the surface temperature of the fixing roller 1 was set to 130 ° C. and the surface temperature of the pressure roller 2 was set to 170 ° C. using a roller having a thickness of 5 mm, an experimental result as shown in FIG. 8 could be obtained.

The surface temperature of the fixing roller 1 is different from the waiting time when the sheet does not pass between the fixing roller 1 and the pressure roller 2 when the sheet passes between the fixing roller 1 and the pressure roller 2. Although it increased slightly, it was at a level that was no problem for implementation. That is, it can be said that a method in which the design condition is set by hijacking the above-described formula as the steady heat conduction when the paper is not passing through between the fixing roller 1 and the pressure roller 2 as the steady heat conduction is practically possible. From this, the invention according to claims 1 and 2 can achieve the object simply and more reliably.

[0036]

As described above, according to the first aspect of the present invention, the fixing roller and the pressure roller which are pressed against each other and are rotatably disposed, and are provided inside the fixing roller and the pressure roller, respectively. The fixing roller heating unit and the pressure roller heating unit, the temperature detection unit for detecting the surface temperature of the pressure roller, and the fixing roller heating unit and the pressure roller heating unit based on a detection signal of the temperature detection unit A heat roller fixing device having a temperature control unit that simultaneously controls the surface temperature of the fixing roller and the surface temperature of the pressure roller to be a predetermined temperature, wherein the fixing roller heating unit and the pressure roller heating unit are The fixing roller has substantially the same configuration as that of the pressure roller, and the fixing roller has a configuration that is the same as the surface temperature of the pressure roller. Has a release layer with a thickness such that the surface temperature of the fixing roller becomes a predetermined temperature, so that it is possible to prevent flaws and abrasion due to contact with the temperature detecting means of the fixing roller, and it is relatively simple without cost. realizable.

According to the second aspect of the present invention, the fixing roller and the pressure roller are rotatably arranged in pressure contact with each other, and the fixing roller heating means provided inside the fixing roller and the pressure roller, respectively. And a pressure roller heating means, a temperature detection means for detecting the surface temperature of the pressure roller, and the fixing roller heating means and the pressure roller heating means are operated by the detection signal of the temperature detection means. And a heat roller fixing device having a temperature control means for simultaneously controlling the surface temperature of the pressure roller to be a predetermined temperature, wherein the fixing roller and the pressure roller are composed of rollers having substantially the same structure, The fixing roller heating means includes heating means for outputting an output such that the surface temperature of the fixing roller becomes a predetermined temperature with respect to the surface temperature of the pressure roller. Since, formic's by the temperature sensing means contacts the fixing roller, it is possible to prevent wear, relatively simple to implement in less cost.

According to the third aspect of the present invention, the fixing roller and the pressure roller are rotatably disposed while being pressed against each other, and the fixing roller heating means provided inside the fixing roller and the pressure roller, respectively. And a pressure roller heating means, a temperature detection means for detecting the surface temperature of the pressure roller, and the fixing roller heating means and the pressure roller heating means are operated by the detection signal of the temperature detection means. And a temperature control means for simultaneously controlling the surface temperature of the pressure roller to a predetermined temperature, wherein the fixing roller heating means and the pressure roller heating means output the same output. And the fixing roller and the pressure roller are composed of rollers having substantially the same configuration and size. 'S, it is possible to prevent wear,
Stable temperature control is possible as compared with the heat roller fixing device according to the first and second aspects, whereby stable fixing performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of the invention according to claim 1;

FIG. 2 is a block diagram showing a circuit configuration of the embodiment.

FIG. 3 is a diagram illustrating the same embodiment.

FIG. 4 is a diagram for explaining the same embodiment.

FIG. 5 is a schematic diagram showing another embodiment of the invention according to claim 1;

FIG. 6 is a diagram for explaining an embodiment of the invention according to claim 2;

FIG. 7 is a view for explaining an embodiment of the invention according to claim 2;

FIG. 8 is a diagram for explaining each embodiment of the invention according to claims 1 and 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3, 4 Heater 5 Thermistor 6 SSR 7 Temperature control circuit 1a, 2a Core layer 1b, 2b Release layer

Claims (3)

[Claims] A fixing roller and a pressure roller, which are rotatably disposed while being pressed against each other; a fixing roller heating means and a pressure roller heating means provided inside the fixing roller and the pressure roller, respectively; Temperature detecting means for detecting the surface temperature of the pressure roller, and detecting the surface temperature of the fixing roller and the surface temperature of the pressure roller by the detection signal of the temperature detecting means. Wherein the fixing roller heating means and the pressure roller heating means comprise heating means for outputting the same output, and the fixing roller comprises The thickness of the fixing roller is substantially the same as that of the pressure roller, and the surface temperature of the fixing roller is a predetermined temperature with respect to the surface temperature of the pressure roller. Heat roller fixing apparatus characterized by having a type layer. 2. A fixing roller and a pressure roller which are rotatably arranged in pressure contact with each other, a fixing roller heating means and a pressure roller heating means provided inside the fixing roller and the pressure roller, respectively. Temperature detecting means for detecting the surface temperature of the pressure roller, and detecting the surface temperature of the fixing roller and the surface temperature of the pressure roller by the detection signal of the temperature detecting means. And a temperature control means for simultaneously controlling the temperature of the fixing roller to a predetermined temperature, wherein the fixing roller and the pressure roller comprise rollers having substantially the same structure, and the fixing roller heating means comprises A heating means for outputting an output such that the surface temperature of the fixing roller becomes a predetermined temperature with respect to the surface temperature of the roller. Apparatus. 3. A fixing roller and a pressure roller which are rotatably arranged in pressure contact with each other, a fixing roller heating means and a pressure roller heating means provided inside the fixing roller and the pressure roller, respectively. Temperature detecting means for detecting the surface temperature of the pressure roller, and detecting the surface temperature of the fixing roller and the surface temperature of the pressure roller by the detection signal of the temperature detecting means. Wherein the fixing roller heating means and the pressure roller heating means comprise heating means for outputting the same output, wherein the fixing roller and the fixing roller A heat roller fixing device, wherein the pressure roller comprises a roller having substantially the same configuration and size.