JP2001117400A - Fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of prolonging the sable life of a fixing belt, exhibiting a stable fixing performance over a long period, also improving a heating efficiency of a heating source, and then, attaining power- saving. SOLUTION: The fixing device is provided with a rotatable fixing belt 73 which is stretched to be laid between at least two supporting rollers 74 and 75, the heating source 76 which is arranged at the inside of the fixing belt 73 so as to heat the inner surface of the fixing belt 73, and at least two pressure rollers 71 and 72 for holding and carrying a transfer material P with a toner image carried while putting the transfer material P on the fixing belt 73, and heating/pressurizing the transfer material P so as to fix the toner image to the transfer material P. A silicone rubber layer, or fluoro-rubber layer, or another heat resistance rubber layer is formed on the inner peripheral surface of the base layer of the fixing belt 73.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, a belt-type fixing device used in an image forming apparatus having a composite function, and an image forming apparatus having the fixing device. It is.

[0002]

2. Description of the Related Art Conventionally, a fixing device used in an electrophotographic image forming apparatus includes a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer and pressing against the heating roller. A heat roller fixing method in which a recording material on which an unfixed toner image is formed is heated while being nipped and conveyed is often used.

[0003] However, in this type of apparatus, the heat capacity of the heating roller is increased, the warm-up time is lengthened, and the temperature inside the elastic layer is increased, thereby shortening the life of the roller. In addition, many color images have a large solid area, and many of the solid images are other than black, and uneven gloss is conspicuous. When a hard roller is used as the above-mentioned heating and pressing roller, unevenness of gloss is generated according to the unevenness of the paper or the toner layer, so that there is a problem that image quality is reduced.

[0004]

In order to solve the above problems, a fixing system using a rubber roller or a rubber belt has been proposed. Using a rubber roller can provide good image quality, but it takes time to warm up and has a problem such as a short life of the roller.This problem becomes more and more noticeable with the speeding up of copiers and printers. It has become to.

[0005] A fixing device using a fixing belt has the following problems. (1) In a conventional fixing belt, a metal belt formed by electroforming or the like on a base of the fixing belt is used in order to achieve both strength and thinness. When the fixing belt is heated by directly irradiating the fixing belt with irradiation light from a heat source, the heat reflected on the surface of the metal belt is high, so that the reflection is repeated in the fixing device. Leaks, irradiates the supporting roller and pressure roller other than the surface to be irradiated, and heats members and parts that do not need to be heated. I was (2) A fixing device including a heating source disposed on the inner surface of the fixing belt, a support roller for rotatably supporting the fixing belt, a pressure roller for heating and pressing the fixing belt and the transfer material in a state where the fixing belt and the transfer material are overlapped. In, the supporting roller for supporting the fixing belt serves as a shield for irradiation light when the fixing belt is heated by the halogen heater, and the irradiation area of the halogen heater is reduced. For this reason, the irradiation heat energy per unit area increases, the temperature of the inner peripheral surface of the fixing belt increases, and the deterioration of the fixing belt is accelerated.

An object of the present invention is to solve each of the above problems,
Provided is a fixing device that improves the service life of a fixing belt, exhibits stable fixing performance over a long period of time, and achieves power saving by improving the heating efficiency of a heating source, and an image forming apparatus including the fixing device. The purpose is to do.

[0007]

According to a first aspect of the present invention, there is provided a fixing device including a fixing belt rotatable around at least two supporting rollers, and a fixing belt disposed inside the fixing belt. A heating source that heats the inner surface of the fixing belt, a transfer material that carries the toner image, and the fixing belt are nipped and conveyed in a superposed state and heated and pressed to fix the toner image onto the transfer material. And a pressure roller, wherein a silicone rubber layer, a fluorine rubber layer, or another heat-resistant rubber layer is formed on the inner peripheral surface of the base layer of the fixing belt. (Claim 1). (2) A fixing device according to the present invention includes a fixing belt that is rotatable around at least two support rollers, a heating source that is disposed inside the fixing belt and heats the inner surface of the fixing belt, and a toner image. A fixing device comprising: at least two pressurizing rollers for fixing the toner image to the transfer material by nipping and transporting the transfer material holding the fixing belt and the fixing belt in a state of being overlapped, and heating and pressing the transfer material. At least one of the support rollers for rotatably supporting the fixing belt is formed of a material having a light transmitting property with respect to at least a part of the wavelength of the electromagnetic wave emitted from the heating source. (Claim 5). (3) The fixing device of the present invention includes a fixing belt rotatable around at least two support rollers, a heating source disposed inside the fixing belt and heating an inner surface of the fixing belt, and a toner image. A fixing device comprising: at least two pressurizing rollers for fixing the toner image to the transfer material by nipping and transporting the transfer material holding the fixing belt and the fixing belt in a state of being overlapped, and heating and pressing the transfer material. The rotating body of the support roller wound around the fixing belt is formed into a hollow cylindrical bag closed with a gas, and the bag is at least a part of the wavelength of the electromagnetic wave irradiated from the heating source. It is characterized by being formed of a material having translucency (claim 11). (4) The image forming apparatus of the present invention includes the above (1), (2),
(3) the pressure roller, the support roller, or the support roller according to any one of the above items;
A fixing device comprising a fixing belt and a heating source is provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fixing device of the present invention and an image forming apparatus provided with the fixing device will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a color printer which is an image forming apparatus provided with the fixing device of the present invention.

This color printer has a flexible endless belt-shaped photosensitive member (hereinafter, referred to as a photosensitive member) 1 serving as an image carrier.
, Four sets of scorotron chargers (hereinafter referred to as chargers) 2Y, 2M, 2C, 2K, four sets of image exposure devices 3
Y, 3M, 3C, 3K, four sets of developing units 4Y, 4M, 4
The image forming units C and 4K (four sets as shown) are arranged in tandem. The illustrated image exposure apparatus 3
Y, 3M, 3C, and 3K use a laser beam scanning optical device.

The photosensitive member 1 is stretched around a driving roller 11, a lower roller 12, and an upper roller 13, and a tension roller 14
And is rotated clockwise as shown in the drawing while being locally brought into contact with the backup member 15 provided on the inner peripheral surface. The backup member 15 is in contact with the inside of the photoreceptor 1 and develops the developing areas of the developer carriers 41Y, 41M, 41C, 41K of the developing units 4Y, 4M, 4C, 4K and the image exposure devices 3Y, 3M, 3C, 3K. The photoconductor 1 is regulated at the 3K image forming position.

At the start of image recording, a drive motor (not shown) is rotated to rotate the photosensitive member 1 clockwise through a drive roller 11, and the photosensitive member is charged by the charging action of a charger 2Y. Application of the potential to 1 is started. Photoconductor 1
Is the first in the image exposure apparatus 3Y after the potential is applied.
Exposure is started by an electrical signal corresponding to the color signal of the photoconductor 1, ie, the yellow (Y) image signal, and the rotation (sub-scanning) of the photoconductor 1 causes the photosensitive layer on the surface to correspond to the yellow (Y) image of the developed image. An electrostatic latent image is formed. The developing device 4Y reversely develops the latent image in a non-contact state on the developer carrying member 41Y by the developing device 4Y to form a yellow (Y) toner image.

Next, the photoreceptor 1 is further provided with a potential on the yellow (Y) toner image by the charging action of the charger 2M, and is converted into a second color signal of the image exposure device 3M, that is, an image signal of magenta (M). Exposure is performed by the corresponding electric signal, and a magenta (M) toner image is formed on the yellow (Y) toner image by non-contact reversal development by the developing device 4M.

By the same process, a cyan (C) toner image corresponding to the third color signal is further formed by the charger 2C, the image exposure device 3C, and the developing device 4C. Further, a black (K) toner image corresponding to the fourth color signal is sequentially superimposed and formed by the charger 2K, the image exposure device 3K, and the developing device 4K, and is formed on the peripheral surface within one rotation of the photoconductor 1. A color toner image is formed.

The color toner image formed on the peripheral surface of the photosensitive member 1 reaches the transfer area after the potential of the attached toner is adjusted by the charger 2F. From the paper feed cassette 51 or the manual paper feed table 53 of the paper feed device 5,
The transfer material P sent out by the registration rollers 55 and conveyed to the registration roller 55 is fed by the driving of the registration roller 55 in synchronization with the passage of the toner image area on the photoconductor 1,
Transfer Means 6 Opposed to Lower Part of Drive Roller 11
The toner image is transferred.

The transfer material P on which the toner image has been transferred is separated from the peripheral surface of the photoreceptor 1 and then conveyed to a fixing device 7. The toner image is melted by the fixing device 7 and fixed on the transfer material P. After the completion of the fixing process, the transfer material P is conveyed by paper discharge rollers 81, 82, and 83 and discharged to a paper discharge tray 84 provided at an upper portion. On the other hand, the photoconductor 1 from which the transfer material P has been separated is cleaned by removing the residual toner by the cleaning blade 91 of the cleaning device 9. When the formation of the toner image of the next original image is subsequently performed, the pre-charging static eliminator 92 exposes the photoconductor surface of the photoconductor 1 to remove the previous charge. (First Embodiment) FIG. 2 shows a first embodiment of the fixing device of the present invention.
And FIG. 3 is a plan view of the fixing device.

In FIG. 2, reference numerals 71 and 72 denote a pair of pressure rollers which can be relatively moved toward and away from each other, and 73 denotes an endless belt-shaped fixing belt. The support rollers 74 and 75 are a pair of support rollers that support and support the fixing belt 73. 76 is a halogen heater as a heating source, 77 is a reflecting plate, 78 is a cleaning means for cleaning the outer peripheral surface of the fixing belt 73, 7
Reference numeral 9 denotes a temperature sensor for detecting the temperature of the fixing belt 73.

At least one of the pair of pressure rollers 71 and 72 has a movable rotating shaft position. At the time of fixing, the fixing belt 73 and the transfer material P are nipped and pressed to be conveyed. At the time of non-fixing, at least one of the rollers, for example, the illustrated pressure roller 72 moves in the direction of the arrow against the pressure contact force, and separates from the pressure roller 71 to form a gap. FIG.
3 is a cross-sectional view illustrating a layer configuration of the fixing belt 73.

The fixing belt 73 has a central metal base 73.
1, outer layer 732 on the outer peripheral surface side, inner layer 733 on the inner peripheral surface side
And so on. Metal substrate 73 of fixing belt 73
1 is made of, for example, an endless belt-shaped nickel metal layer formed by electroforming. An outer layer 732 coated with silicone rubber is provided on the outer peripheral surface of the metal base 731.
Are formed. The outer layer 732 includes a pressure roller 71,
The transfer material P carrying the toner at the nip position 72
Since it is heated and pressurized while being moved in a state of being overlapped, heat resistance and toner releasability are compatible. The silicone rubber layer of the outer layer 732 has, for example, a thickness of 0.2 mm and a rubber hardness of 3 °.
弾 性 60 ° (JISA) elasticity.

A fixing belt 7 is provided on the toner image on the transfer material P.
The outer layer 732 made of silicone rubber 3 is in contact with the fixing belt 73 heated by the halogen heater 76 while being in uniform contact with the transfer material P and the unevenness of the toner image due to the elasticity of the silicone rubber. , Pressure roller 7
By the pressing by 1, 72, uniform fixing without gloss unevenness is performed.

An inner layer 733 is formed on the inner peripheral surface of the metal base 731 of the fixing belt 73. Inner layer 733
Is formed by applying silicone rubber in which carbon is dispersed on the inner peripheral surface of the metal substrate 731, and absorbs the irradiation light of the halogen heater 76 with high efficiency and minimizes the irradiation light leaking to the periphery of the device. As much as possible. That is, the fixing belt 7
The third inner layer 733 is coated with silicone rubber in which carbon as an infrared absorbing material is dispersed, has a high absorption rate of irradiation light, and is heated to a predetermined temperature (for example, 190 ° C.) in a short time by heating by the halogen heater 76. Temperature rises to

Since the silicone rubber forming the inner layer 733 has flexibility, unlike a normal heat-resistant paint,
The fixing belt 73 does not peel off due to bending during rotation. The thickness of the silicone rubber layer forming the inner layer 733 is slightly different depending on conditions such as the circumference of the fixing belt 73 and the linear velocity, but is 500 μm so as not to impair the heat supply speed to the outer layer 732 of the fixing belt 73. It is desirable to apply to the following very thin layers. The lower limit of the thickness of the inner layer 733 is appropriately determined according to the allowable range such as uniform application properties, strength, and service life of the silicone rubber layer.

The fixing belt 73 is stretched between the support roller 74 and the support roller 75 with a very weak tension of 0.5 kg / cm or less, more preferably 0.2 kg / cm or less. Alternatively, it may be in a state where the tension is loosened. The fixing belt 73 is rotated by rotation of the support roller except during the fixing process. Fixing belt 73 during fixing process
Are rotated by being pressed by the pressure rollers 71 and 72. The rotation speed of the fixing belt 73 is the same as the transfer speed of the transfer material P.

As shown in FIG. 3, the supporting roller 74 has a roller portion 74A formed with a spiral projection having an inclination angle with respect to the axial direction of the rotating shaft 74B, and a rotating shaft 74B driven and rotated by a driving source. , A flange member 74C connected to both ends of the roller portion 74A, and a gear 74D fixed to one shaft end of the rotating shaft 74B and connected to a driving source.

The support roller 75 is formed by a roller portion 75A having a spiral projection having an inclination angle with respect to the axial direction of the rotation shaft 75B, a rotation shaft 75B, and a flange member 75C connected to both ends of the roller portion 75A. Become. Roller part 74
A and 75A are materials having heat resistance to the fixing temperature of the halogen heater 76 and having low thermal conductivity, for example,
It is formed of foamed silicone rubber or the like.

The rollers 74A and 75A are
B and 75B were formed by integrally molding silicone rubber or other heat-resistant resin on the outer periphery, or a cord-shaped silicone rubber was spirally wound around the outer peripheral surface of a hollow cylindrical member made of metal or resin to form a projection. The thing etc. are used. Spiral protrusions are formed on the roller portions 74A and 75A in order to reduce the contact area with the fixing belt 73 so as to remove heat from the fixing belt 73 as much as possible. Thus, when the fixing device 7 is warmed up, only the fixing belt 73 needs to be heated, and there is no heat that is lost to the core metal or the like as compared with the conventional roller fixing method or the like, so that the warming-up time can be significantly reduced. Was. In addition, since the projecting portion has a spiral shape, the fixing belt 73 and the roller
4A and 75A are continuously in contact with each other, and the operation noise of the fixing belt 73 is reduced.

When both the support roller 74 and the support roller 75 are driven by the driving device of the main body of the image forming apparatus, the direction of the inclination angle of the spiral projection formed on the roller portion 74A of the support roller 74 is determined. The direction of the inclination angle of the spiral projection formed on the roller portion 75A of the support roller 75 is reversed. Fixing belt 73 with spiral protrusions
Of the roller portion 74A and the roller portion 75
The direction A is opposite to the direction A, and the offset of the fixing belt 73 due to the provision of the spiral protrusion is prevented.

One of the two support rollers 74, 75 is driven by the fixing belt 73, such that the support roller 75 rotates by being transmitted from the support roller 74 via the fixing belt 73. In this case, the direction of the force for biasing the fixing belt 73 is reversed by making the inclination angle directions of the spiral protrusions the same direction, and similarly, the occurrence of the biasing of the fixing belt 73 is prevented.

The fixing belt 73, which is stretched with a very weak tension, is provided on the inclined surfaces of the flange members 74C provided at both ends of the roller portion 74A and the flange members 75C provided at both ends of the roller portion 75A. Meandering, roller section 74
A, Prevents deviation from 75A. Support roller 74
Is driven and rotated clockwise as indicated by an arrow by a power unit of the image forming apparatus main body. As the support roller 74 rotates, the fixing belt 73 and the driven-side support roller 75 are rotated clockwise. The design value of the driving speed of the fixing belt 73 is the transfer material P
And the same transport speed. The peripheral speed of the pressure rollers 71 and 72 is driven to be the same as the driving speed of the fixing belt 73.

Inside the fixing belt 73 between the pressure roller 71 and the supporting roller 74 on the upstream side in the conveying direction of the fixing belt 73, one or more rod-shaped halogen heaters 76 are arranged. The halogen heater 76 is a pressure roller 71
A lower region inside the fixing belt 73 between the roller and the support roller 74 is irradiated and heated to a predetermined temperature. At the same time as or before the transfer material P carrying the toner image is conveyed to the fixing area via the conveyance guide plate 56, the pressure roller 72 arranged outside the fixing belt 73 is raised, Pressure is applied across the transfer material P and the fixing belt 73. The toner image on the transfer material P is fixed to the transfer material P by the heating of the fixing belt 73 by the heat and the nipping and pressing by the pressure rollers 71 and 72.

A predetermined load acts on the support shafts 72A at both ends of the pressure roller 72 toward the pressure roller 71 when sandwiched by a spring member, and a constant pressure acts on the pressure contact portions of the pressure rollers 71 and 72. It is supposed to. The intensity of this pressure is 0.2 to 2 kg / cm, preferably 0.6 to 1.0 per unit length in a direction parallel to the axis of the pressure roller 72.
It has been adjusted to kg / cm.

The pressing by the pressing rollers 71 and 72 may be performed by moving the pressing roller 71 downward and the pressing roller 72 upward. Since the peripheral speed of the pressure roller 71 or the pressure roller 72 is driven at the same speed as the moving speed of the fixing belt 73, no excessive force is applied to the fixing belt 73 and the transfer material P. I have. After the fixing, the pressure rollers 71 and 72 are released from the pressure contact, so that distortion and deviation due to a minute speed difference between the fixing belt 73 and the pressure rollers 71 and 72 are eliminated. , 72 is prevented.

A fixing belt 73 is attached to the toner image on the transfer material P.
Contact with the transfer material P and the unevenness of the toner image due to the elasticity of the silicone rubber, and uniformly contact the heat of the fixing belt 73 heated by the halogen heater 76 and the pressure roller 71, By the pressurization by 72, uniform fixing without gloss unevenness is performed.

The fixed transfer material P is applied to a pressure roller 71,
When the air exits from the nip portion 72, the air is cooled by the outside air, so that offset and improper separation during separation can be avoided. (Second Embodiment) FIG. 5 shows a second embodiment of the fixing device of the present invention.
FIG. 6 is a plan view of a fixing device. Note that, in the reference numerals used in these drawings, portions having the same functions as those in the first embodiment are denoted by the same reference numerals. Further, points different from the above embodiment will be described.

In FIG. 5, 74E is a halogen heater 7
6 is a light-transmitting support roller formed of a material having a light-transmitting property with respect to at least a part of the wavelength of the electromagnetic wave irradiated from 6. Reference numeral 76 denotes a halogen heater serving as a heating source, and reference numeral 77 denotes a reflection plate that shields irradiation light to the pressure roller 71. As shown in FIG. 6, the drive side support roller 74 includes left and right flange members 74C1 and 74C2 and a flange member 74C.
Transparent support roller 74 fixed at both ends to 1,74C2
E.

The translucent support roller 74E is a hollow cylindrical body having translucency and heat resistance. Translucent support roller 74
E is polyimide (PI), polyamide imide (PA
I), a resin material such as polytetrafluoroethylene (PTFE), or heat-resistant glass. A rotating shaft 74B1 integral with one flange member 74C1 is fitted and supported by a bearing 702 of a fixing device main body side plate 701, and is driven and rotated by a gear 74D fixed to a shaft end and connected to a driving source.

The rotating shaft 74B2, which is integral with the other flange member 74C2, is connected to the bearing 70 of the fixing device main body side plate 703.
4 and is supported. A vent 74B3 is formed in the center of the rotating shaft 74B2 and the flange member 74C2 to communicate with the internal space of the translucent support roller 74E. The air circulation of the ventilation port 74B3 prevents the pressure change in the internal space due to the temperature change of the driving-side support roller 74, and eliminates the pressure difference between the air pressure in the translucent support roller 74E and the outside air.

The support roller 75 has a roller portion 75A1 formed with a spiral protrusion having an inclination angle with respect to the axial direction of the rotating shaft 75B, and a roller portion 75A2 formed with a spiral protrusion having an inverse inclination angle. , A flange member 75C connected to both ends, and a rotating shaft 75B. The rollers 75A1 and 75A2 have heat resistance to the fixing temperature of the halogen heater 76 and are formed of a material having a low thermal conductivity, such as foamed silicone rubber.

The roller portions 75A1 and 75A2 are
5B in which silicone rubber or other heat-resistant resin is integrally molded on the outer circumference, or a hollow cylindrical member made of metal or resin, in which a cord-like silicone rubber is spirally wound around the outer circumference to form a projection. Is used. Flange members 74C1, 74 provided at both ends of the translucent support roller 74E
On the inclined surface of C2 and the inclined surfaces of the flange members 75C provided at both ends of the roller portions 75A1 and 75A2, the fixing belt 73 stretched with very weak tension meanders, and the translucent support roller 74E and the roller Prevents deviation from the parts 75A1 and 75A2.

The support roller 74 is driven and rotated clockwise as indicated by an arrow by a power unit of the image forming apparatus main body. With the rotation of the support roller 74, the fixing belt 73 and the support roller 75 are rotated clockwise. The design value of the driving speed of the fixing belt 73 is the same as the transport speed of the transfer material P. The peripheral speed of the pressure rollers 71 and 72 is driven to be the same as the driving speed of the fixing belt 73.

The halogen heater 76 disposed inside the fixing belt 73 between the supporting roller 74 on the upstream side in the conveying direction of the fixing belt 73 and the pressing roller 71 is connected to the pressing roller 7.
The downstream region L and the upstream region U inside the fixing belt 73 between the first roller 1 and the support roller 74 are directly irradiated and heated.
The halogen heater 76 simultaneously irradiates and heats the downstream region L and the upstream region U inside the fixing belt 73 to thereby increase the irradiation energy per unit area as compared with the case where only the downstream region L is irradiated. And the temperature rise on the inner surface of the fixing belt 73 can be reduced.

The halogen heater 76 is a light-transmitting support roller 74 of a light-transmissive and heat-resistant support roller 74.
E illuminates the front side of E, heats it and transmits it, passes through the internal space, irradiates the translucent support roller 74E again and heats it,
Further, except for a part of the absorbed light, the light reaches the fixing belt 73 and heats the winding surface side of the fixing belt 73. Thus, the irradiation light of the halogen heater 76 is transmitted to the translucent support roller 74E.
Directly heats the inner surface of the fixing belt 73 in the upstream area U and the downstream area L, heats the translucent support roller 74E, and further heats the translucent support roller 74 of the fixing belt 73.
The winding surface of E is heated, and a large area on the inner surface side of the fixing belt 73 is heated to a predetermined temperature. In this embodiment, since the effective heating area is widened, the heat flux per unit area is small, the temperature rise of the inner peripheral surface of the fixing belt 73 is suppressed, and the deterioration of the fixing belt 73 can be reduced. In addition, by eliminating the reflection plate shown in the first embodiment, the heat capacity is reduced by that amount, and the remaining heat time can be shortened. (Third Embodiment) FIG. 7 shows a third embodiment of the fixing device of the present invention.
FIG. 8 is a cross-sectional view of the support roller. Note that, in the reference numerals used in these drawings, parts having the same functions as those in the second embodiment are given the same reference numerals. Further, points different from the above embodiment will be described.

The fixing belt 73 is rotatably supported by support rollers 740 and 750. Since the support roller 740 connected to the driving source and the support roller 750 driven and rotated via the fixing belt 73 have substantially the same shape, the configuration of the support roller 740 will be described below with reference to FIG. The support roller 740 includes a translucent bag 741 made of a hollow cylindrical elastic body, a rotating shaft 742 driven and rotated by a driving source, a flange member 743 connected to both ends of the translucent bag 741, and a rotating shaft 742. And a gear 744 fixed to one shaft end and connected to a drive source.

The translucent bag 741 is provided with a halogen heater 76.
It is formed of a material having a light-transmitting property with respect to at least a part of the wavelength of the electromagnetic wave irradiated from the substrate. The translucent bag 741 has heat resistance to the fixing temperature of the heating unit 76, has low thermal conductivity, and has elasticity.
Or, it is formed of any one of a flexible thin film, a laminated material in which rubber is selectively added thereto, and a composite material thereof.

That is, the translucent bag 741 is formed of a thin film made of a resin material such as aromatic polyamide, polyimide, or polyamideimide. The thickness of the translucent bag 741 is preferably from 10 to 200 μm. Translucent bag 741
Is a light-transmissive bag that is formed in a balloon shape made of a hollow cylindrical elastic body whose both ends are sealed by a flange member 743, and seals the periphery of the rotation shaft 742 of the support roller 740 via a gas layer. The internal pressure of 741 is set higher than the atmospheric pressure.

The thickness of the translucent bag 741 is extremely thin and the heat capacity is small as compared with the hollow cylinder made of hard resin. The light-transmitting bag 741 has a small cross-sectional area due to a small thickness, and has low heat conduction in a direction parallel to the rotation shaft 742. Further, since the light-transmitting bag 741 has a small thickness, the amount of heat that escapes through the flange member 743 is small. Therefore, the heat taken from the fixing belt 73 to the translucent bag 741 is very small.

Thus, when the fixing device 7 is warmed up, only the fixing belt 73 needs to be heated, and there is no heat taken by the core metal or the like as compared with the conventional roller fixing method or the like, so that the warming-up time can be greatly reduced. It is now possible. In addition, near the both ends of the translucent bag 741,
A flange member 743 having an outer diameter larger than the outer diameter of the bag body 741 is provided to prevent the fixing belt 73 from shifting.

[0047]

According to the present invention, the following effects can be obtained by the configuration described above. (1) The fixing belt of the fixing device of the present invention has a silicon rubber layer in which carbon is dispersed on the inner peripheral surface of the base layer of the fixing belt, so that highly efficient light absorption is obtained and heat loss is reduced. The fixing belt can be heated in a small amount, and high-efficiency heat supply is realized. (2) The supporting roller for supporting the fixing belt is formed by a hollow cylindrical body or a transparent bag having a light transmitting property with respect to at least a part of the wavelength of the electromagnetic wave emitted from the halogen heater. The effect of the roller shielding is eliminated, and the effective heating area for the fixing belt can be increased. Thereby, the deterioration of the fixing belt is reduced. Also, by reducing the number of reflectors that shield the support roller, it is possible to reduce the remaining heat time of the fixing belt. (3) The pressure roller, support roller, fixing belt of the present invention,
An image forming apparatus equipped with a fixing device consisting of a heating source and a reflector makes it possible to save power by improving thermal efficiency, shorten warming-up time, fix images at high speed and achieve high image quality, and stabilize and form images with excellent maintainability with a long service life. An apparatus is provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a color printer that is an image forming apparatus equipped with a fixing device of the present invention.

FIG. 2 is a sectional view showing a first embodiment of the fixing device of the present invention.

FIG. 3 is a plan view of the fixing device.

FIG. 4 is a cross-sectional view illustrating a layer configuration of a fixing belt.

FIG. 5 is a cross-sectional view illustrating a fixing device according to a second embodiment of the invention.

FIG. 6 is a plan view of the fixing device.

FIG. 7 is a cross-sectional view illustrating a fixing device according to a third embodiment of the present invention.

FIG. 8 is a sectional view of a support roller.

[Explanation of symbols]

 56 transport guide plate 7 fixing device 71, 72 pressure roller 73 fixing belt 74 support roller 74A, 75A, 75A1, 75A2 roller portion 74B, 75B, 74B1, 74B2 rotation shaft 74B3 vents 74C, 75C, 74C1, 74C2 flange member 74D Gear 74E Translucent support roller 75 Support roller 76 Halogen heater (heating source) 77 Reflector 78 Cleaning means 731 Metal substrate 732 Outer layer 733 Inner layer 740 Support roller 741 Translucent bag 743 Flange member 750 Support roller P Transfer material U Upstream area L Downstream area

Claims (15)

[Claims] An image forming apparatus comprising: a fixing belt rotatable around at least two support rollers; a heating source disposed inside the fixing belt for heating an inner surface of the fixing belt; and a transfer material carrying a toner image. And at least two pressure rollers for fixing the toner image to the transfer material by nipping, conveying, and heating and pressing in a state where the fixing belt and the fixing belt are overlapped. A fixing device comprising a silicone rubber layer, a fluorine rubber layer, or another heat-resistant rubber layer formed on an inner peripheral surface of the layer. 2. The fixing device according to claim 1, wherein carbon is dispersed in a silicone rubber layer, a fluorine rubber layer, or another heat-resistant rubber layer of the fixing belt. 3. The fixing belt according to claim 1, wherein a thickness of a silicone rubber layer, a fluorine rubber layer, or another heat-resistant rubber layer is 5 mm.
The fixing device according to claim 1, wherein the thickness of the fixing device is equal to or less than 00 μm. 4. The fixing device according to claim 1, wherein a silicone rubber layer is formed on an outer peripheral surface of the base layer of the fixing belt. 5. A fixing belt rotatable around at least two support rollers, a heating source disposed inside the fixing belt and heating an inner surface of the fixing belt, and a transfer material carrying a toner image. And at least two pressurizing rollers for fixing the toner image to the transfer material by nipping and transporting the toner image onto the transfer material by heating and pressurizing the fixing belt in a state where the fixing belt is overlapped with the fixing belt. A fixing device, wherein at least one of the supporting rollers movably supported is formed of a material having a light transmitting property with respect to at least a part of the wavelength of the electromagnetic wave irradiated from the heating source. 6. The fixing device according to claim 5, wherein the support roller formed of the light-transmitting material is a hollow cylindrical body made of a heat-resistant resin. 7. The fixing device according to claim 5, wherein the light-transmissive and heat-resistant support roller is a hollow cylindrical body made of a fluororesin or a polyimide resin. 8. The fixing device according to claim 5, wherein the light-transmissive and heat-resistant support roller is a hollow cylindrical body made of heat-resistant glass. 9. A support roller comprising a hollow cylindrical body and a rotary shaft, a ventilation hole is formed in a part of the support roller to eliminate a pressure difference between an internal space of the support roller and outside air. The fixing device according to claim 5. 10. The fixing device according to claim 5, wherein the heating source is a halogen heater. 11. A fixing belt rotatable around at least two support rollers, a heating source disposed inside the fixing belt and heating an inner surface of the fixing belt, and a transfer material carrying a toner image. And at least two pressure rollers for fixing the toner image to the transfer material by nipping and transporting the fixing belt with the fixing belt in a state of being stacked and heating and pressing the fixing belt.
In the fixing device, the rotating body of the support roller wound around the fixing belt is a hollow cylindrical bag closed with gas, the bag is at least electromagnetic waves emitted from the heating source. A fixing device, wherein the fixing device is formed of a material having translucency for some wavelengths. 12. The fixing device according to claim 11, wherein the gas pressure inside the bag is higher than the atmospheric pressure. 13. The bag formed of the translucent material is formed of either a resin having elasticity, a flexible thin film, or a laminated material in which rubber is selectively added thereto. The fixing device according to claim 11, wherein: 14. The heating source includes: an inner surface of the fixing belt on an upstream side of the translucent support roller; an outer periphery of the translucent support roller; and a downstream of the translucent support roller. 14. The fixing device according to claim 5, wherein an inner surface of the fixing belt is heated. 15. An image forming apparatus comprising: a fixing device comprising a pressure roller, a support roller, a fixing belt, and a heating source according to claim 1. Description: