JPH08248790A - Fixing device - Google Patents

Abstract

PURPOSE: To provide a fixing device capable of increasing heat efficiency of a heating body in minimizing the heat absorption from the heating body to the heating body supporting body, and attaining power saving and waste time shortening as a merit of a film heating system. CONSTITUTION: In the fixing device imparting heat energy of the heating body 3 to a heat receiving body through a heat resistance film 2, by holding pressure roller (pressure member) 4 in press contact with the heating body 3 fixed-supported by the heating body supporting body 1 across a heat resistant film 2, and guiding the heat receiving material between the heat resistance film 2 and the pressure roller corresponding to the running travel of the heat resistance film 2, a sealing layer 8 is provided on a rear side of the heating body 3. As a result, the heat absorption from the heating body 3 to the heating body supporting body 1 is minimized by a thermal insulation effect of the sealing layer 8, and moreover the heat loss caused by convection of the air in the case of simply providing a gap can be prevented, therefore the heat efficiency of the heating body 3 is increased by the heat insulation effect coupled with the effect as mentioned above and the heating body supporting body 1, and thus the power can be saved, the waist time shortened and so forth, as the merit of the film heating system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for applying heat energy to a heated material such as a recording material sheet via a heat resistant film.

[0002]

2. Description of the Related Art As a fixing device used in an image forming apparatus, many types such as a heat roller type, a heat plate type, a belt fixing type and a flash fixing type have been known so far, and they have already been put to practical use. There is.

Recently, a heating element fixedly supported by a metal or resin holder, a heat-resistant film (fixing film) conveyed while being pressed against the heating element, and a recording material are heated through the heat-resistant film. A method for fixing an unfixed image formed and carried on the surface of a recording material by applying heat of a heating body to the recording material through a heat-resistant film, thereby fixing the unfixed image on the surface of the recording material by heat. A fixing device (film heating method) having a structure has been proposed.

To such a fixing device, the system and device disclosed in, for example, Japanese Unexamined Patent Publication No. 62-313182, which has been proposed by the present applicant, belongs to the fixing device. The fixing device proposed by the present applicant has a thin endless or endless heat-resistant film (sheet), a moving driving means for the film, and a fixed support on one side of the film with the film inside. A heating member arranged in this state, and a pressing member which is arranged on the other surface side so as to face the heating member and which makes the developed image bearing surface of the recording material to be image-fixed adhere to the heating member via the film. It is configured to include.

In such a fixing device, the film travels at the same speed in the forward direction as the recording material to be image-fixed which is conveyed and introduced between the film and the pressure member at least during image fixing. Then, the recording material is passed through a fixing nip portion as a fixing portion formed by pressure contact between a heating body and a pressing member, with the traveling moving film being sandwiched between the recording material and the visible image bearing surface of the recording material. Then, heat energy is applied to the visible image (unfixed toner image) carried on the recording material to soften and melt it, and then the film and recording material after passing through the fixing section are separated. Separation is performed.

In the fixing device adopting such a film heating system, a low heat capacity heating body can be used as a heating body. Therefore, as compared with the conventional contact heating system such as a heat roller system and a belt heating system. It is possible to save power and shorten wait time (quick start). In addition, the film heating method is effective because it has an advantage that the drawbacks of the conventional heating method can be solved.

[0007]

By the way, in the fixing device adopting the film heating method as described above, the heating member is conventionally formed on the heating member support made of a composite material of resin and ceramics, metal, glass or the like. Is closely attached and fixedly supported.

[0008] Thus, although the above-mentioned heating body support is itself heat-insulating, the heat of the heating body is considerably absorbed by this heating body support, and the fixing device is from this heating body support. Thermal efficiency is reduced because heat is dissipated in the air inside the main body and the image forming apparatus incorporating the fixing device, and the power saving by using a low heat capacity heating element, which is a great advantage of the film heating method, This is a factor that reduces the merit of reducing the wait time.

In order to solve the above problem, it is possible to increase the heat insulation efficiency by providing a gap between the heating body and a support body that supports the heating body in a fixed manner. However, due to the convection of air in the gap. Insulation effect may be insufficient.

The present invention has been made in view of the above problems, and an object of the present invention is to enhance heat efficiency of a heating body by minimizing heat absorption from the heating body to the heating body support, thereby improving the film heating system. Another object of the present invention is to provide a fixing device capable of achieving power saving, shortening of wait time, etc.

[0011]

To achieve the above object, the invention according to claim 1 presses a pressure member through a heat resistant film to a heating body fixedly supported by the heating body support, Fixing in which a material to be heated is introduced between the heat resistant film and the pressing member as the heat resistant film travels and the heat energy of the heating body is applied to the material to be heated via the heat resistant film. In the device, a sealing layer is provided on the back surface of the heating body.

According to a second aspect of the present invention, a pressure member is brought into pressure contact with the heating element fixedly supported by the heating element support through a heat-resistant film, and the heat-resistant film is moved along with the traveling movement of the heat-resistant film. In the fixing device, which introduces a material to be heated between the heating member and the pressure member, and applies the heat energy of the heating body to the material to be heated through the heat resistant film, the heating body and the heating body support. It is characterized in that a sealing layer is provided between the two.

According to a third aspect of the present invention, a pressure member is brought into pressure contact with the heating body fixedly supported by the heating body support through a heat resistant film, and the heat resistant film is moved along with the traveling movement of the heat resistant film. In the fixing device, which introduces a material to be heated between the heating member and the pressure member, and applies the heat energy of the heating body to the material to be heated through the heat resistant film, the heating body and the heating body support. It is characterized in that a sealed vacuum layer is provided between the two.

The invention according to claim 4 is characterized in that, in the invention according to claim 2, the sealing layer has a multilayer structure.

A fifth aspect of the invention is characterized in that, in the first to third or fourth aspects of the invention, the sealing layer or the vacuum layer has a shape distribution in the longitudinal direction.

[0016]

According to the present invention, in the fixing device adopting the film heating system, the heat absorption from the heating body to the heating body support is suppressed to a minimum by the adiabatic action of the sealing layer or the vacuum layer, and moreover, simply. Heat loss due to convection of air in the case of providing a void is prevented, and the thermal efficiency of the heating body is enhanced by the combination of these and the adiabatic action of the heating body support,
The advantages of the film heating method are power saving and reduction of wait time.

[0017]

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

<First Embodiment> FIG. 1 is a schematic sectional view of a fixing device adopting a film heating system according to the present invention. In FIG. 1, 2 is an endless heat resistant film,
The film 2 is a guide member for the heating body support 1
Is fitted on. The inner peripheral length of the endless heat-resistant film 2 is set to be, for example, about 3 mm larger than the outer peripheral length of the heating body support 1 including the heating body 3. Therefore, the film 2 has a peripheral length with respect to the heating body support 1. Is loosely fitted outside with a margin.

By the way, the heat resistant film 2 has a film thickness of 100 μm or less, preferably 50 μm or less in order to reduce its heat capacity and improve quick start property.
Single layer of PTFE, PFA, EFP with high heat resistance of 0 μm or more, or polyimide, polyamide-imide, PEEK, P
PTFE, PFA, FEP on the outer peripheral surface of ES, PPS, etc.
It is composed of a composite layer film coated with etc.
In this example, the film 2 used was a polyimide film coated with PTFE on the outer peripheral surface.

The heating element 3 is formed by coating an electric resistance material such as Ag / Pd (silver-palladium) on the surface of a substrate made of alumina or the like with a thickness of about 10 μm and a width of 1 to 3 mm by screen printing or the like. The protective layer 7 is coated with glass, fluororesin, or the like.

On the other hand, in FIG. 1, reference numeral 4 is a pressure roller, and the pressure roller 4 forms a nip with the heating body 3 so as to sandwich the film 2, and rotates to drive the heat resistant film 2. Functions as the body. This pressure roller 4
Is composed of a cored bar 4a and a heat-resistant rubber 4b having good releasability such as silicon rubber, and is driven by an unillustrated drive means from the end of the cored bar 4a.

The temperature control in the fixing device according to the present embodiment is performed by the thermistor 5 provided on the heating body 3.
The output of is converted into A / D and taken into the CPU 10, and based on the information, the AC voltage applied to the heating element 3 by the triac 11 is subjected to pulse width modulation such as phase and wave number control,
It is performed by controlling the electric power supplied to the heating element.

By the way, in this embodiment, the heater support 1
A groove 1a is formed along the longitudinal direction on the heating body mounting surface side in a range where the heating body 3 can be fixedly supported, and the groove 1a is completely sealed to form a sealing layer 8. The width and the lengthwise dimension of the groove 1a are set larger than those of the heat generating portion 7 on the heating body 3, and the depth thereof is set to 0.1 mm or more.

Although the heat insulation effect of the sealing layer 8 suppresses the heat removal from the heating body 3 to the heating body support 1,
However, heat loss due to convection of air in the case of simply providing a gap is prevented, and the heat insulating effect of the heating body support 1 is combined to enhance the thermal efficiency of the heating body 3, which is an advantage of the film heating method. It is possible to reduce power consumption and wait time.

The image forming apparatus used in this embodiment has a process speed of 47 mm / sec. According to the experiment, when a heater substrate having a heating element having a length of 216 mm and a width of 4 mm is used as the heating element 3, the heating element 3 is closely fixed to a conventional flat heater support without interposing an air layer. In the case of being supported, the temperature control temperature at the time of 100 V input was 190 ° C. at the time of the first start-up in the morning, and 170 ° C. at the final temperature control.

On the other hand, the heater support has a length of 230 m.
In order to obtain the same fixability as in the case where the heating element is fixedly supported through a gap, a groove having a width of m, a width of 6 mm, and a depth of 0.5 mm is fixedly supported. The temperature control temperature is 185 ℃ at the time of one-time start-up, and the final temperature control is 1
It was 65 ° C. Also, the power consumption is about 300W
However, the power consumption is about 285W and the power consumption is about 5
It was possible to reduce by%. Furthermore, the wait time is about 1
It was shortened by 0%.

In the case where the heat insulating layer formed by the voids is completely closed to form the closed layer, the temperature control temperature at the time of 100 V input is 180 ° C. at the first start-up in the morning and 160 ° C. at the final temperature control.
The same fixability was obtained at ° C. In addition, the power consumption at this time was about 270 W, which was reduced by about 10% and the wait time was also reduced by about 15% as compared with the case where they were closely fixed and supported.

<Second Embodiment> Next, a second embodiment of the present invention will be described.

In the first embodiment, as shown in FIG. 1, a sealing layer 8 is provided between the heating body 3 and the heating body support 1, and the heat insulating effect of the sealing layer 8 causes the heating body 3 to move to the heating body support. The heat efficiency of the heating element 3 is improved by suppressing the heat removal to the heating element 1.

On the other hand, in the present embodiment, the inside of the sealing layer 8 between the heating element 3 and the heating element support 1 is evacuated, and the vacuum layer is provided to further enhance the heat insulating effect. .

In this experiment, the same fixing property was obtained when the temperature control temperature was 172 ° C. at the start-up in the morning and 158 ° C. at the final temperature control at the time of 100 V input. The power consumption at this time is about 265.
It was W, which was reduced by about 12% and the wait time was also reduced by about 18% as compared with the case of closely fixing and supporting.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. 2 is a schematic sectional view of a fixing device according to the third embodiment of the present invention. In this figure, the same elements as those shown in FIG. 1 are designated by the same reference numerals.

In this embodiment, as shown in FIG. 2, it is possible to enhance the heat insulating effect by forming the heat insulating sealing layer 12 into a multi-layer structure. Even in the case of the configuration shown in FIG.
The same effects as those of the first and second embodiments can be obtained, and
When 0V was input, the temperature control temperature was 180 ° C. at the first startup in the morning, and the final temperature control was 160 ° C., and the same fixability was obtained. In addition, the power consumption at this time is about 270 W, which is about 10% less than the case where it is closely fixed and supported, and the wait time is also about 15
% Shortened.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIG. Note that FIG. 3 is a schematic view of the heating body 3 and the heating body support 1 on which the heating body bonding surfaces are viewed from above.

In the first, second and third embodiments, the longitudinal resistance distribution of the heating element 3 itself, the installation position of the thermistor 5, the temperature fuse position (not shown), and the pressure roller 4 are also provided. Due to various factors such as the pressurization state and the shape of the heater support 1 in the longitudinal direction, the temperature distribution in the longitudinal direction of the fixing device as a whole cannot be said to be uniform. If the temperature distribution in the longitudinal direction of the entire fixing device is not uniform,
The fixing property in the longitudinal direction of the fixing device becomes uneven.

Therefore, in this embodiment, by providing a shape distribution in the longitudinal direction of the heat insulating sealing layer or the heat insulating vacuum layers 8a and 8b, the temperature distribution in the longitudinal direction of the fixing device as a whole is made uniform. did.

As the fixing device used in this embodiment, a fixing device having a thermistor at the end of the heating element 3 was used. With such a configuration, the temperature distribution in the longitudinal direction of the fixing device as a whole tends to decrease at both ends. In order to make the temperature distribution in the longitudinal direction uniform, as shown in FIG. 3, an adiabatic sealing layer or adiabatic vacuum layers 8a, 8b are used.
It suffices to have a distribution in the shape in the longitudinal direction of the above. In the present embodiment, the cross-sectional area S1 in the width direction of both ends of one heat-insulating sealing layer or heat-insulating vacuum layer 8b is made larger than the center cross-sectional area S2 By S1> S2), the temperature distribution in the longitudinal direction can be made uniform, and thereby the fixing property in the longitudinal direction as the fixing device can be made uniform.

[0038]

As is apparent from the above description, according to the present invention, the heat absorption from the heating body to the heating body support is suppressed to a minimum by the heat insulating function of the sealing layer or the vacuum layer, and further,
This is an advantage of the film heating method because heat loss due to convection of air in the case of simply providing a void is prevented, and the heat-insulating action of the heating body support is combined to enhance the thermal efficiency of the heating body. It is possible to obtain an effect that it is possible to reduce power consumption and shorten wait time.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a fixing device according to first and second embodiments of the present invention.

FIG. 2 is a schematic sectional view of a fixing device according to a third exemplary embodiment of the present invention.

FIG. 3 is a schematic view of a heating body and a heating body support surface of a heating body supporting body according to a fourth embodiment of the present invention as seen from above.

[Explanation of symbols]

 1 Heater Support 2 Heat Resistant Film 3 Heater 4 Pressure Roller (Pressure Member) 8 Insulation Sealing Layer 12 Multilayer Sealing Layer

Claims (5)

[Claims] 1. A pressure member is pressed against a heating body fixedly supported by a heating body support through a heat-resistant film, and the heat-resistant film and the pressure member are moved as the heat-resistant film travels. In a fixing device for introducing a material to be heated between and applying heat energy of the heating body to the material to be heated through the heat resistant film, a sealing layer is provided on a back surface of the heating body. Fixing device. 2. A heating member fixedly supported by a heating member support is pressed against a heating member through a heat resistant film, and the heat resistant film and the pressing member are moved along with the traveling movement of the heat resistant film. In a fixing device that introduces a material to be heated in between and applies heat energy of the heating body to the material to be heated through the heat resistant film, a sealing layer is provided between the heating body and the heating body support. A fixing device provided. 3. A heating member fixedly supported on a heating member support is pressed against a pressing member via a heat resistant film, and the heat resistant film and the pressing member are moved along with the traveling movement of the heat resistant film. In a fixing device that introduces a material to be heated in between and applies the heat energy of the heating body to the material to be heated through the heat resistant film, it is sealed between the heating body and the heating body support. A fixing device having a vacuum layer. 4. The fixing device according to claim 2, wherein the sealing layer has a multi-layer structure. 5. The fixing device according to claim 1, wherein the sealing layer or the vacuum layer has a shape distribution in the longitudinal direction.