JP2000187408A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of less power consumption. SOLUTION: In a fixing device 1 which has a fixing roller 2 with a heat source Q in it and a pressure roller 12 pressed to the fixing roller 2 firmly and fixes an unfixed image to a recording medium under heat and pressure by passing the recording medium with the unfixed image on it between both the rollers 2 and 12, a first insulator 3 disposed near the fixing roller 2 with a small amount of empty space (air layer) A left between them and a second insulator 4 disposed apart from the first insulator 3 are provided, the fixing roller 2, the first insulator 3, and the second insulator 4 being disposed in that order. Because, an air layer B with a low heat-conductivity is formed between the first insulator 3 and the second insulator 4, an insulation effect which is the same as that produced when thin insulator is provided is obtained. This makes it difficult for the heat of the fixing roller 2 to be transferred to the surrounding of the fixing device and hence enables a less power consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A fixing device is built in an image forming apparatus. In this fixing device, an unfixed image is carried between a fixing roller having a built-in heat source and a pressing roller pressed against the fixing roller. The unfixed image is fixed on the recording medium by passing through the recording medium (paper) and applying heat and pressure.

One of the problems of such a fixing device is to reduce power consumption. As a countermeasure, it has been proposed that the frame of the fixing roller be made of a resin material having a lower thermal conductivity than metal. I have. FIG. 5 shows such a fixing device 10. The fixing device 10 includes a fixing roller 2 incorporating a heat source Q, a pressure roller 12, a fixing roller frame / heat insulating material 13 made of a resin material having high heat resistance, and the like. It is composed of

Further, in a fixing device of a high load type (a total load of 50 kgf or more), the strength of the frame is not sufficient to form the frame only with a resin material.
A configuration in which the periphery is covered with a resin material having low thermal conductivity is also employed. FIG. 6 shows such a fixing device 20. The fixing device 20 includes a fixing roller 2 including a heat source Q, a fixing roller frame 23 formed of a metal material (for example, a cold-rolled steel plate or the like), and a fixing roller frame 23. The heat roller 24 is made of a heat-resistant resin material that covers the fixing roller frame 23.

[0005]

However, the conventional fixing devices 10 and 20 shown in FIGS. 5 and 6 have the following problems.

First, in the fixing device 10 shown in FIG.
The fixing roller 2 is heated from the inside by the built-in heat source Q, and at the same time, the air layer in the space C is also heated. Thereafter, a fixing roller frame and a heat insulating material 13 made of a resin material are interposed via an air layer.
Is heated, and heat is transmitted to the surroundings. Further, the air in the heated space C flows out from the gap between the fixing roller 2 and the heat insulating material 13 to the surroundings.

In the fixing device 20 shown in FIG.
Although heat is transmitted to the surroundings in substantially the same manner as the fixing device 10 shown in FIG. 5, the heat transfer is faster because the fixing roller frame 23 is made of metal.

That is, even if the fixing roller is covered with a resin material having a lower thermal conductivity than metal, the energy efficiency is poor due to a large amount of heat escaping from the fixing device into the image forming apparatus main body. There was a problem that it did not lead to electric power.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a fixing device capable of realizing low power consumption.

[0010]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a fixing roller having a built-in heat source; and a pressure roller pressed against the fixing roller. A fixing member for fixing the unfixed image to the recording medium by heat and pressure by passing the recording medium carrying the unfixed image through the first heat insulating material disposed close to the fixing roller with a small space therebetween And at least one second heat insulating material arranged at a distance from the first heat insulating material, and the fixing roller, the first heat insulating material, and the second heat insulating material are arranged in this order. I do.

According to a second aspect of the present invention, there is provided a fixing roller having a built-in heat source, and a pressure roller pressed against the fixing roller, and a recording medium carrying an unfixed image is passed between the two rollers. In a fixing device for fixing an unfixed image on a recording medium by heat and pressure, a first heat insulating material disposed close to the pressure roller with a small space therebetween, and a first heat insulating material separated from the first heat insulating material by a distance At least one second heat insulating material is provided, and the pressure roller, the first heat insulating material, and the second heat insulating material are arranged in this order.

According to a third aspect of the present invention, in the first aspect, the first heat insulating material or the second heat insulating material also serves as a fixing roller frame.

According to a fourth aspect of the present invention, in the second aspect, the first heat insulating material or the second heat insulating material also serves as a pressure roller frame.

According to a fifth aspect of the present invention, in the first to third or fourth aspects of the present invention, the first heat insulating material covers 50% or more around the fixing roller or the pressure roller.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the first heat insulating material covers at least 50% of the upper portion of the fixing roller or the pressure roller.

A seventh aspect of the present invention is characterized in that, in the first to fifth or sixth aspects of the present invention, the first and second heat insulating materials are made of a heat-resistant resin material.

According to an eighth aspect of the present invention, in the first to sixth or seventh aspects of the present invention, the first heat insulating material and the second heat insulating material are connected by a relay member having a heat conductivity of 0.1 kcal / mhr ° C. or less. And a substantially sealed air layer is formed by the first and second heat insulating materials and the relay member.

According to a ninth aspect of the present invention, in the eighth aspect, the relay member is formed of a foam.

According to a tenth aspect of the present invention, there is provided a fixing roller having a built-in heat source, and a pressure roller pressed against the fixing roller, and a recording medium carrying an unfixed image is passed between the two rollers. A fixing device for fixing an unfixed image to a recording medium by heat and pressure, wherein a fixing roller frame supporting the fixing roller is formed of metal, wherein a fixing roller frame is provided between the fixing roller and the fixing roller frame. A first heat insulating material disposed in close proximity to the fixing roller with a small space therebetween, and the first heat insulating material;
And a fixing roller, a first heat insulating material, a second heat insulating material, and at least one second heat insulating material arranged at a distance.
The heat insulating materials are arranged in this order.

According to the present invention, there is provided a fixing roller having a built-in heat source and a pressure roller which is pressed against the fixing roller, and a recording medium carrying an unfixed image is passed between the two rollers. A fixing device for fixing an unfixed image on a recording medium by heat and pressure, wherein the pressing roller frame supporting the pressing roller is made of metal, wherein the pressing roller and the pressing roller frame are provided. A first heat insulating material disposed between the body and a pressure roller and a small space therebetween and the first heat insulating material;
And a pressure roller, a first heat insulating material, a second heat insulating material, and at least one second heat insulating material arranged at a distance.
The heat insulating materials are arranged in this order.

According to a twelfth aspect of the present invention, in the tenth or eleventh aspect, the first heat insulating material covers 50% or more around the fixing roller or the pressure roller.

The thirteenth aspect of the present invention provides the tenth and the first aspects.
13. The invention according to 1 or 12, wherein the first heat insulating material covers at least 50% of the upper part of the fixing roller or the pressure roller.

The invention according to claim 14 is the invention according to claims 10 to 1
14. The invention according to 2 or 13, wherein the first and second heat insulating materials are made of a heat-resistant resin material.

The invention according to claim 15 is the invention according to claims 10 to 1
15. In the invention described in 3 or 14, the first heat insulating material and the second heat insulating material are joined by a relay member having a thermal conductivity of 0.1 kcal / mhr ° C. or less, and the first and second heat insulating materials and the relay member are connected. And that a substantially closed air layer is formed.

According to a sixteenth aspect, in the fifteenth aspect, the relay member is formed of a foam.

Therefore, according to the first or second aspect of the present invention, since an air layer having low thermal conductivity is formed between the first heat insulating material and the second heat insulating material, a thick heat insulating material is provided. As a result, the same heat insulating effect can be obtained, and the heat of the fixing roller or the heating roller is less likely to be transmitted to the periphery of the fixing device, thereby realizing low power consumption.

According to the third or fourth aspect of the present invention, the first
Since the heat insulating material or the second heat insulating material also functions as the fixing roller frame or the pressure roller frame, it is possible to reduce the power consumption while reducing the size and cost of the fixing device.

According to the fifth or twelfth aspect of the present invention, the first heat insulating material covers the periphery of the fixing roller or the pressure roller by 50%.
As described above, effective heat insulation can be performed.

According to the sixth or thirteenth aspect of the invention, the air heated by the fixing roller or the pressure roller tends to rise, but the first heat insulating material covers the upper part of the fixing roller or the pressure roller by 50%. % Or more, more effective heat insulation can be performed.

According to the seventh or fourteenth aspect of the present invention, the first and second heat insulating materials are made of a heat-resistant resin, so that they are not deformed by heat and are versatile as a heat-resistant resin. If a resin is used, the cost can be reduced.

According to the invention described in claim 8 or 15, since the first heat insulating material and the second heat insulating material are joined by the relay member having low thermal conductivity to form a substantially sealed air layer,
The heat transmitted to the second heat insulating material is further reduced, and a more effective heat insulating effect is obtained.

According to the ninth or sixteenth aspect of the present invention, since the relay member is made of a foam, it is advantageous not only in heat conductivity and cost but also in the first heat insulating member close to the fixing roller or the pressure roller. The thermal expansion of the material can be absorbed, and a stable device configuration can be realized.

According to the invention described in claim 10 or 11,
When the fixing roller frame or the pressure roller frame is a metal frame, heat is transmitted through a metal frame having a high thermal conductivity, but the fixing roller and the fixing roller frame or the pressure roller and the pressure roller frame are transmitted. A first heat insulating material is disposed between the body and the fixing roller or the pressure roller in close proximity with a small space therebetween, and a second heat insulating material is provided at a distance from the first heat insulating material. Since an air layer with low thermal conductivity was formed between the two heat insulating materials, the same heat insulating effect as when a thick heat insulating material was provided was obtained, and the heat of the fixing roller or the heating roller was not easily transmitted to the periphery of the fixing device. Electricity can be realized.

[0034]

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

<First Embodiment> FIG. 1 is a front sectional view of a fixing device according to a first embodiment of the present invention, and FIG. 2 is a side sectional view of an identification attaching device.

The fixing device 1 according to the present embodiment is installed in the main body of an image forming apparatus such as a copying machine. The fixing device 1 is a device for fixing an unfixed image. The fixing device 1 includes a fixing roller 2 having a heat source Q built therein, and a pressure roller 12 which is pressed against the fixing roller 2 and is driven to rotate. The fixing roller 2 is heated from the inside by a heat source Q incorporated therein. The surface of the fixing roller 2 is provided with a temperature detecting unit (not shown) for detecting the surface temperature.
Is kept almost constant. In order to improve the heat response, the core of the fixing roller 2 is made of, for example, aluminum (A5056, A6063, etc.) having a high thermal conductivity.
Is used.

In the present embodiment, the fixing roller 2 is rotatably supported by the second heat insulating material 4 (or the first heat insulating member) via the ball bearing 50. A heat insulating bush 8 is interposed between the fixing roller 2 and the ball bearing 50 so that the heat of the fixing roller 2 is not easily transmitted to the second heat insulating material 4. A driving force is transmitted to the fixing roller 2 via the gear 9, and a voltage is applied to the heat source Q via the electrode 7.

An upper half of the fixing roller 2 facing the inside of the second heat insulating material 4 is covered with a semi-cylindrical first heat insulating material 3. A narrow air space A is formed between the two. Further, both sides and the front rear of the first heat insulating material 3 are in close contact with the second heat insulating material 4 via the relay member 5 between the first heat insulating material 3 and the second heat insulating material 4. , A closed air layer B is formed.

Therefore, in the fixing device 1 according to the present embodiment, the heat of the fixing roller 2 heats the narrow air layer A by heat transfer and convection, and the first heat insulating material 3 is formed through the air layer A. Heat. Thereafter, the heat generated by heating the heat insulating material 3 heats the air layer B.
The air in the air layer B does not flow to the outside area even if the air in the air layer B is warmed up because the space enclosed by the heat insulating material 4 and the relay member 5 is formed. Therefore, the air layer B having a low thermal conductivity (the thermal conductivity of air is about 0.02 kcal / mh)
(° C.) plays a role of a heat insulating material, thereby preventing heat from flowing out of the fixing device 1 and performing efficient heat insulation. Here, the gap between the fixing roller 2 and the first heat insulating material 3 is set to 3 ± 1 mm in consideration of thermal expansion, dimensional tolerance of parts, and the like. Actually, since a temperature detecting means (not shown) is attached to the surface of the fixing roller 2, a slight gap is formed in the first heat insulating material 3, but there is no problem.

Incidentally, since the air heated by the fixing roller 2 tends to rise, the first heat insulating material 3 is formed as shown in FIG.
It is effective to cover 50% or more of the upper half of the fixing roller 2 as shown in FIG.

However, unlike the vertical fixing device 1 according to the present embodiment, in the case of a horizontal fixing device in which a sheet is conveyed vertically in the fixing device, not the upper portion but the right and left peripheral portions. By covering 50% or more, a high heat insulating effect can be expected.

Here, the first heat insulating material 3 and the second heat insulating material 4 are made of PPS, PBT, PET or the like in consideration of cost, heat insulation (thermal conductivity), heat resistance, mechanical strength and the like. Composed of heat-resistant general-purpose resin. In particular, it is desirable to use a resin containing glass fiber having a high heat resistance and a small thermal expansion coefficient for the first heat insulating material 3 which is heated to a high temperature because it is disposed close to the fixing roller 2.

When a material having a low thermal conductivity (0.1 kcal / mh.degree. C. or less), such as urethane foam or silicone foam, is used as the material of the relay member 5, it is difficult to conduct heat, and the thermal expansion between parts is reduced. The effect of absorbing the distortion due to the difference can be expected.

In this embodiment, only the heat insulation of the fixing roller has been described. However, in a fixing device in which the positions of the fixing roller and the pressure roller are reversed, the same structure as described above is applied to the pressure roller. The same effect can be expected by adopting.

Further, it is effective to arrange the above-mentioned heat insulating material on both the fixing roller and the pressure roller.

By performing the above-described heat insulation, the power consumption of the fixing device 1 can be reduced, and the safety of the user during jam clearance can be improved.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a front sectional view of the fixing device according to the second embodiment of the present invention, and FIG. 4 is a side sectional view of the identification attaching device. In these drawings, the same elements as those shown in FIGS. Are denoted by the same reference numerals, and description thereof will be omitted below.

The fixing device 1 according to the present embodiment is different from the fixing device 1 according to the first embodiment in that the fixing roller frame is constituted by a metal frame (for example, a cold-rolled steel plate) 6 and the metal frame is provided. The point is that the first heat insulating material 3 and the second heat insulating material 4 are provided between the body 6 and the fixing roller 2.

It is convenient to employ this embodiment in a high-load type fixing device in which the nip between the fixing roller 2 and the pressure roller 12 has a total load of 50 kgf or more.

Since the metal has high thermal conductivity, the first heat insulating material 3 and the second heat insulating material 4 are provided inside the metal frame 6.
In addition, since the heat transfer, the material of the members, and the like are the same as those in the first embodiment, the description thereof is omitted.

[0051]

As is apparent from the above description, claim 1
According to the invention described in (2), since an air layer having a low thermal conductivity is formed between the first heat insulating material and the second heat insulating material, the same heat insulating effect as when a thick heat insulating material is provided can be obtained. , The heat of the fixing roller or the heating roller is hardly transmitted around the fixing device,
As a result, low power consumption can be realized.

According to the third or fourth aspect of the present invention, the first
Since the heat insulating material or the second heat insulating material also functions as the fixing roller frame or the pressure roller frame, it is possible to reduce the power consumption while reducing the size and cost of the fixing device.

According to the fifth or twelfth aspect of the present invention, the first heat insulating material covers the periphery of the fixing roller or the pressure roller by 50%.
As described above, effective heat insulation can be performed.

According to the sixth or thirteenth aspect, the air heated by the fixing roller or the pressure roller tends to rise, but the first heat insulating material covers the upper portion of the fixing roller or the pressure roller by 50%. % Or more, more effective heat insulation can be performed.

According to the seventh or fourteenth aspect of the present invention, since the first and second heat insulating materials are made of a heat resistant resin, they are not deformed by heat, and are versatile as a heat resistant resin. If a resin is used, the cost can be reduced.

According to the invention as set forth in claim 8 or 15, since the first heat insulating material and the second heat insulating material are joined by the relay member having low thermal conductivity to form a substantially sealed air layer,
The heat transmitted to the second heat insulating material is further reduced, and a more effective heat insulating effect is obtained.

According to the ninth or sixteenth aspect of the present invention, since the relay member is made of a foam, it is advantageous not only in heat conductivity and cost but also in the first heat insulating member close to the fixing roller or the pressure roller. The thermal expansion of the material can be absorbed, and a stable device configuration can be realized.

According to the tenth or eleventh aspect of the present invention,
When the fixing roller frame or the pressure roller frame is a metal frame, heat is transmitted through the metal frame having a high thermal conductivity, but the fixing roller and the fixing roller frame or the pressure roller and the pressure roller frame are transmitted. A first heat insulating material is disposed between the body and the fixing roller or the pressure roller in close proximity with a small space therebetween, and a second heat insulating material disposed at a distance from the first heat insulating material is provided. Since an air layer with low thermal conductivity was formed between the two heat insulating materials, the same heat insulating effect as when a thick heat insulating material was provided was obtained, and the heat of the fixing roller or the heating roller was not easily transmitted to the periphery of the fixing device. Electricity can be realized.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a fixing device according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the fixing device according to the first embodiment of the present invention.

FIG. 3 is a front sectional view of a fixing device according to a second embodiment of the present invention.

FIG. 4 is a side sectional view of a fixing device according to a second embodiment of the present invention.

FIG. 5 is a front sectional view of a conventional fixing device.

FIG. 6 is a front sectional view of a conventional fixing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fixing device 2 fixing roller 3 first heat insulating material 4 second heat insulating material 5 relay member 6 metal frame 12 pressure roller A, B air layer Q heat source

Claims (16)

[Claims] 1. A fixing roller having a built-in heat source and a pressure roller pressed against the fixing roller, wherein a recording medium carrying an unfixed image is passed between the two rollers, and the recording medium is undetermined by heat and pressure. In a fixing device for fixing an attached image on a recording medium, a first heat insulating material arranged close to the fixing roller with a small space therebetween, and at least one heat insulating material arranged at a distance from the first heat insulating material A fixing device comprising: a second heat insulating material; and a fixing roller, a first heat insulating material, and a second heat insulating material arranged in this order. 2. A fixing roller having a built-in heat source and a pressure roller pressed against the fixing roller, wherein a recording medium carrying an unfixed image is passed between the two rollers, and the temperature is undetermined by heat and pressure. In a fixing device for fixing an attached image to a recording medium, a first heat insulating material arranged close to the pressure roller with a small space therebetween, and at least one heat insulating material arranged at a distance from the first heat insulating material. And a second heat insulating material, and a pressure roller, a first heat insulating material, and a second heat insulating material are arranged in this order. 3. The fixing device according to claim 1, wherein the first heat insulating material or the second heat insulating material also functions as a fixing roller frame. 4. The fixing device according to claim 2, wherein the first heat insulating material or the second heat insulating material also functions as a pressure roller frame. 5. The fixing device according to claim 1, wherein the first heat insulating material covers at least 50% of the periphery of the fixing roller or the pressure roller. 6. The fixing device according to claim 5, wherein the first heat insulating material covers at least 50% of an upper portion of the fixing roller or the pressure roller. 7. The fixing device according to claim 1, wherein the first and second heat insulating members are made of a heat-resistant resin material. 8. The first heat insulating material and the second heat insulating material are connected by a relay member having a thermal conductivity of 0.1 kcal / mhr ° C. or less, and the first and second heat insulating materials and the relay member are substantially connected. 7. A sealed air layer is formed.
Or the fixing device according to 7. 9. The fixing device according to claim 8, wherein the relay member is formed of a foam. 10. A fixing roller having a built-in heat source and a pressure roller pressed against the fixing roller, wherein a recording medium carrying an unfixed image is passed between the two rollers, and the temperature is undetermined by heat and pressure. A fixing device for fixing an attached image on a recording medium, wherein the fixing roller frame supporting the fixing roller is made of metal, wherein a fixing roller and a small amount of fixing roller are provided between the fixing roller and the fixing roller frame. A first heat insulating material disposed close to the space and at least one second heat insulating material disposed at a distance from the first heat insulating material; a fixing roller, a first heat insulating material, 2. A fixing device, wherein the heat insulating material is arranged in the order of 2. 11. A fixing roller having a built-in heat source and a pressure roller pressed against the fixing roller, wherein a recording medium carrying an unfixed image is passed between the two rollers, and the recording medium is undetermined by heat and pressure. A fixing device for fixing an image formed on a recording medium, wherein the pressing roller frame supporting the pressing roller is made of metal, wherein a fixing device is provided between the pressing roller and the pressing roller frame. A first heat insulating material disposed close to the pressure roller with a small space therebetween, and at least one second heat insulating material disposed at a distance from the first heat insulating material; A fixing device, wherein the first heat insulating material and the second heat insulating material are arranged in this order. 12. The fixing device according to claim 10, wherein the first heat insulating material covers 50% or more around a fixing roller or a pressure roller. 13. The fixing device according to claim 10, wherein the first heat insulating material covers at least 50% of an upper portion of the fixing roller or the pressure roller. 14. The fixing device according to claim 10, wherein the first and second heat insulating members are made of a heat-resistant resin material. 15. The first heat insulating material and the second heat insulating material are connected by a relay member having a thermal conductivity of 0.1 kcal / mhr ° C. or less, and the first and second heat insulating members and the relay member are substantially connected. 11. A sealed air layer is formed.
15. The fixing device according to any one of items 13 to 14. 16. The fixing device according to claim 15, wherein the relay member is formed of a foam.