JP3582421B2 - Fixing device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixing device such as an electrophotographic copying machine such as a PPC or a laser printer.
[0002]
[Prior art]
A fixing device such as an electrophotographic copying machine has a heating roller for heating and fixing an unfixed toner image on a recording material, for example, copy paper, and a pressing roller for pressing the recording material against the heating roller. As the heating roller, an aluminum pipe having good thermal conductivity coated with Teflon or the like is often used. Inside the heating roller, a tube-shaped heater lamp is disposed along the axis thereof, and the heat of the heater lamp heats the heating roller to a temperature of about 180 ° C. When the recording material is supplied between the heating roller and the pressure roller, the heat of the heating roller is transmitted to the unfixed toner image on the recording material and is fixed.
[0003]
Therefore, when starting copying, it is necessary to raise the temperature of the heating roller to this temperature, and a warm-up time is required. Further, when the copying operation is temporarily interrupted, the heating roller is preheated to a temperature of about 160 ° C. so that copying can be performed immediately when the operation is resumed, and standby power is required.
[0004]
[Problems to be solved by the invention]
For this reason, the present applicant has proposed in Japanese Utility Model Laid-Open No. 64-32567 a fixing device which hardly requires a warm-up time or a standby heating. FIG. 4 is a cross-sectional view of a main part of the fixing device, in which a heating roller 2 formed of a translucent member is rotatably disposed, and a pressure roller 3 is in close contact with the heating roller 2. Rotate. Then, the recording material P on which the unfixed toner image is formed passes between the heating roller 2 and the pressure roller 3 in a state of being in close contact with the heating roller 2. A tubular heater lamp 4 is arranged inside the heating roller 2, and a reflector 5 made of, for example, an aluminum plate is arranged behind the heater lamp 4. Then, light including infrared rays emitted from the heater lamp 4 is directly or reflected by the reflector 5, passes through the heating roller 2, and is irradiated on the recording material P. That is, the unfixed toner on the recording material P is fixed by light including infrared rays radiated from the heater lamp 4, so that copying is possible even when the heater lamp 4 is turned on at the same time as the start of copying, and the warm-up time is increased. And little need for standby heating.
[0005]
In such a fixing device, the heating roller 2 in the area located on the back surface of the reflection plate 5 is only heated by the radiant heat of the reflection plate 5, so that even if the copying operation is continued, the heating roller 2 rises too much. Without warming, the toner image is largely fixed by light, including infrared. However, since the degree of light absorption differs depending on the density of the toner, it has been found that in the case of a document having a light toner image, light is not sufficiently absorbed and fixing is insufficient.
In addition, since the reflection plate 5 is disposed in the heating roller 2, the heating roller 2 cannot be downsized, and there is a problem that the apparatus cannot be downsized.
[0006]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device which can fix a toner image reliably without requiring a warm-up time or a standby heating, and can cope with miniaturization.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, the present invention provides a method in which a heating roller in which a tubular heater lamp is disposed rotatably and a pressure roller which rotates in close contact with the heating roller is provided. In a fixing device for fixing a toner image by passing a recording material on which an unfixed toner image is formed, a heating roller is formed of a translucent member that transmits near-infrared rays and absorbs far-infrared rays. On the outer surface of the outer surface that does not face the pressure roller, a wavelength conversion reflection film that changes the light of the heater lamp into far infrared rays is formed.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 shows an example of a fixing device incorporated in an electrophotographic copying machine. A pair of support members 11 are erected on a substrate 1. Bearings 12 are fitted to the small-diameter portions 21 and 31 at both ends of the heating roller 2 and the pressure roller 3, and the heating roller 2 and the pressure roller 3 are rotatably supported by these bearings 12 in a state of being in contact with each other. It is attached to the member 11. Gears 13, 13 meshing with each other are also fitted to the small diameter portions 21, 31 of the heating roller 2 and the pressure roller 3, respectively, and when the pressure roller 3 is rotated by a driving device (not shown). The heating roller 3 rotates in the opposite direction. Accordingly, when the recording material P is conveyed between the rotating heating roller 2 and the pressing roller 3, the recording material P is pressed by the two rollers 2 and 3 and advances, and is sent out from the two rollers 2 and 3.
[0009]
The heating roller 2 is made of a translucent member, for example, heat-resistant glass such as quartz glass or lead glass. These glasses have a property of transmitting near infrared rays well but absorbing far infrared rays well. The heating roller 2 is, for example, a cylindrical body having an outer diameter of φ40 mm and a length of 236 mm. In the heating roller 2, a heater lamp 4, which is a tubular halogen lamp, is arranged along the axis thereof. The rated power consumption of the heater lamp 4 is, for example, 300 W. The wavelength conversion reflective film 6 is coated on the outer surface of the heater lamp 4 which is not opposed to the pressure roller 3 as indicated by a dotted line for convenience.
[0010]
The wavelength conversion reflection film 6 is formed by dispersing in a particulate far-infrared radiation material or a binder.
The particulate far-infrared radiation material contains quartz, but in addition to quartz, various inorganic oxides, carbides, and nitrides can be used. Specific examples of particulate far-infrared radiation materials other than quartz include metal oxides other than quartz, such as aluminum oxide, copper oxide, cobalt oxide, manganese dioxide, titanium dioxide, nickel oxide, zinc oxide, silicon carbide, titanium carbide, and the like. Composite oxides such as carbides, silicates such as zircon, copper-manganese black, nickel-manganese-iron-cobalt black, titanium-barium-nickel yellow, iron-nickel-aluminum brown, and cobalt-silica violet Pigments and the like. These particulate far-infrared radiation materials other than quartz are selected in consideration of the far-infrared radiation efficiency and the like, and can be used alone or in combination of two or more kinds together with quartz.
The binder is obtained by heating and curing a partially hydrolyzed sol of a composite alkoxide comprising an alkoxide of at least one metal selected from titanium, aluminum and zirconium and an alkoxide containing silicon.
[0011]
A composition in which the particulate far-infrared radiating material is dispersed in the partially hydrolyzed sol is applied to a predetermined outer surface of the heater lamp 4 to a thickness of, for example, about 50 to 400 μm by a spray coating method or the like, and is preliminarily dried. If sintering is performed later, the wavelength conversion reflection film 6 can be formed.
[0012]
The wavelength conversion reflection film 6 has, for example, the wavelength conversion characteristics shown in FIG. That is, when the light having the spectral wavelength indicated by the dotted curve enters the wavelength conversion reflective film 6, the light having the spectral wavelength indicated by the solid curve converted to the longer wavelength side of about 0.5 μm is emitted from the wavelength conversion reflective film 6. You.
[0013]
When the start button of the electrophotographic copying machine is turned on, the recording material P is exposed, and a toner image corresponding to the original image is formed on the recording material P. As shown in FIG. Conveyed during. At the same time when the start button is turned on, the heater lamp 4 is turned on, and the direct light from the heater lamp 4 and the light containing a large amount of near-infrared light reflected by the wavelength conversion reflection film 6 pass through the heating roller 2 and become a recording material. P is irradiated. Then, the toner image is fixed by absorbing the light.
On the other hand, near-infrared light that has passed through the wavelength conversion reflective film 6 is converted into far-infrared light and applied to a portion of the heating roller 2 located on the side opposite to the pressing roller 3. As it absorbs, the temperature rises efficiently. Then, since the heating roller 2 which has become high temperature rotates and presses against the recording material P, the heat of the heating roller 2 is transmitted to the recording material P, and the toner image is also fixed by this heat.
[0014]
As described above, since the toner image is fixed by the light transmitted through the heating roller 2 made of a translucent member, the toner image can be fixed even when the heater lamp 4 is turned on at the same time as the start of copying. Need very little. Therefore, the efficiency of the copying operation is improved, and the energy saving effect is extremely large. Since the toner image is fixed also by the heat of the heating roller 2 which has absorbed the far-infrared ray converted by the wavelength conversion reflection film 6 and has become high in temperature, even if the toner image has a light color that hardly absorbs light. It is possible to fix firmly.
Further, unlike the conventional example, since the reflection plate is not disposed in the heating roller 2, the heating roller 2 can be downsized, which contributes to downsizing of the apparatus.
[0015]
【The invention's effect】
As described above, according to the present invention, an undetermined state is provided between a heating roller in which a tubular heater lamp is disposed freely and a pressure roller which rotates in close contact with the heating roller. In a fixing device for fixing a toner image by passing a recording material on which an attached toner image is formed, a heating roller is formed of a translucent member that transmits near-infrared rays and absorbs far-infrared rays. Of these, the wavelength conversion reflective film that changes the light of the heater lamp to far infrared rays is formed on the outer surface that does not face the pressure roller, so that the toner image can be securely fixed with almost no need for warm-up time or standby heating. In addition, a fixing device that can cope with downsizing can be obtained.
[Brief description of the drawings]
FIG. 1 is a partial sectional view of an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA of FIG.
FIG. 3 is a characteristic curve diagram of a wavelength conversion reflection film.
FIG. 4 is an explanatory diagram of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 11 Support member 12 Bearing 13 Gear 2 Heating roller 21 Small diameter part of heating roller 3 Pressure roller 31 Small diameter part of pressure roller 4 Heater lamp 5 Reflector 6 Wavelength conversion reflective film P Recording material

Claims (1)

A recording material on which an unfixed toner image is formed between a heating roller which is rotatably disposed and has a tubular heater lamp disposed therein, and a pressure roller which rotates in close contact with the heating roller. In the fixing device for fixing the toner image by passing
The heating roller is made of a translucent member that transmits near-infrared rays and absorbs far-infrared rays. Of the outer surfaces of the heater lamp, the outer surface of the heater lamp that does not face the pressure roller applies the far-infrared light to the heater lamp. A fixing device, wherein a wavelength conversion reflection film for changing the wavelength is formed.

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