JP2002072731A - Fixing apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing apparatus which quickly reaches fixing tempera ture and whose warm-up time is short, and an image forming apparatus equipped with the fixing apparatus and capable of realizing quick start. SOLUTION: This fixing apparatus is equipped with a heating roller 38, a heating belt 39 wound round the roller 38, and a pressing roller 40 arranged to be opposed to the roller 38 while holding the belt 39 in between. A halogen lamp 41 is arranged inside the belt 39 and also the surface of the roller 38 and the inside surface of the belt 39 are painted in black after blast treatment. Thus, light irradiated from the lamp 41 is efficiently absorbed on the inside surface of the belt 39 and the surface of the roller 38, whereby the fixing temperature is quickly attained, rapid fixing operation in a short warm-up state is secured, and rapid image formation is realized by quick start from the time of supplying power.

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 fixing toner on paper and an image forming apparatus such as a laser printer provided with the fixing device.

[0002]

2. Description of the Related Art An image forming apparatus such as a laser printer is
Usually, a process device and a fixing device are provided, and the process device transfers a visible image developed by toner from an electrostatic latent image formed on a photosensitive drum to a sheet fed by a feed roller. Then, in the fixing device, a predetermined image is formed by heating and fixing the toner transferred to the sheet.

A fixing device used in such an image forming apparatus, for example, for fixing a monochrome image, includes a metal heating roller containing a light source such as a halogen lamp and a rubber disposed opposite to the heating roller. A pressure roller is provided, and heat fixing is performed while the sheet passes between the heating roller and the pressure roller.

In fixing a color image,
Since the toner layer formed on the paper becomes thicker, the image may be crushed when pressed by a metal heating roller. For example, instead of such a metal heating roller, a rubber heating roller may be used. Various types have been proposed in which a heater, a heating belt, and the like are heated by a light source such as a halogen lamp.

[0005]

However, in the above-described fixing device, since the heating roller is heated by the light source, there is a problem that it takes time to warm up the heating roller to reach a predetermined fixing temperature. In particular, when a color image is formed, a heating roller made of rubber or a heating belt is heated, so that it takes a longer time to reach a fixing temperature than a heating roller made of metal, so that it takes a longer time to warm up. There is a problem that the image forming apparatus cannot be quickly started because of a long time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a fixing device capable of quickly reaching a fixing temperature and having a short warm-up time. An object of the present invention is to provide an image forming apparatus having a fixing device and capable of performing a quick start.

[0007]

Means for Solving the Problems To achieve the above object, an invention according to claim 1 includes a heating roller, a heating belt wound around the heating roller, the heating roller and the heating belt. A fixing device for fixing a developer formed on a recording medium, wherein the heating belt and the heating belt are disposed on the heating roller side with respect to the heating belt. A light source for irradiating the roller with light is provided, and at least one of the heating belt and the heating roller,
It is characterized in that light absorption processing for absorbing the light is performed on a surface that receives light emitted from the light source.

According to such a configuration, the light emitted from the light source is applied to the heating belt and the heating roller.
The surface of at least one of the heating belt and the heating roller, which receives the light emitted from the light source, is subjected to light absorption processing for absorbing the light. Well absorbed. Therefore, the fixing temperature can be quickly reached, and a quick fixing operation with short warm-up can be ensured.

Further, since it is sufficient that at least the surface receiving the light emitted from the light source is subjected to such light absorption processing, in the case of the heating belt, the opposite surface, that is, the pressing roller, It is not necessary to perform such a light absorption treatment on the surface on the side that comes in contact with the recording medium, and therefore, without affecting the fixability of the developer on the recording medium, Fixation can be achieved.

[0010] The invention described in claim 2 is the same as the claim 1.
In the invention described in the above, the surface of the heating belt and the heating roller that receives light from the light source is a process formed by a light absorbing material, a coating process, a blast process,
It is characterized in that at least one light absorption process selected from a chemical process has been performed.

When light absorption processing is performed by such various processing, light emitted from a light source can be reliably and efficiently absorbed. Therefore, a quick fixing operation with a short warm-up can be reliably achieved.

Further, the invention described in claim 3 is the first invention.
Wherein the surface of the heating belt that receives light from the light source is formed to have a larger surface roughness than the surface of the heating belt that does not receive light from the light source. And

According to such a configuration, the light emitted from the light source is received on the light receiving surface of the heating belt. The light-receiving surface is formed so that the surface roughness is larger than the surface on the opposite side of the light-receiving surface, so that the surface area is larger, and the irradiated light can be efficiently emitted on the light-receiving surface. Absorbed. Therefore, the fixing temperature can be quickly reached, and a quick fixing operation with a short warm-up time can be further ensured. Also, the surface opposite to the light receiving surface of the heating belt, that is, the surface facing the pressure roller and coming into contact with the recording medium does not receive light, so it is not necessary to increase the surface roughness, and priority is given to the fixing property of the developer. Since the surface roughness may be determined in consideration of the above, the influence on the fixing property of the developer on the recording medium is less affected, and good fixing of the developer can be achieved.

Further, since the light receiving surface of the heating belt is opposed to the heating roller, if the surface roughness is large, the frictional resistance between the heating belt and the heating roller increases.
Slip between the heating belt and the heating roller is prevented,
Secure transmission of drive from the heating roller to the heating belt can be ensured.

According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising the fixing device according to any one of the first to third aspects.

When such a fixing device is provided, a quick fixing operation with a short warm-up time can be ensured, so that a quick start can be performed from the time of turning on the power and a quick image formation can be achieved.

The invention described in claim 5 is the same as the invention in claim 4.
The present invention is characterized in that a color image can be formed.

When a color image is formed, the developer layer formed on the recording medium becomes thicker, so that when the contact surface of the developer is pressed by a metal heating roller, the image may be crushed. Therefore, it is preferable to heat the contact surface of the developer from the inside of the rubber heating roller.However, when the contact surface of the developer is heated from the inside of such a rubber heating roller, compared with the metal heating roller, Therefore, since the heat conduction speed of rubber is lower than that of metal, it takes a long time to reach the fixing temperature.

However, since the image forming apparatus of the present invention is provided with a fixing device capable of ensuring a quick fixing operation with a short warm-up time, a rubber roller is used as the heating roller and the heating belt. A quick start can be made from the time of power-on, and a quick image formation can be realized while a small good color image can be formed.

[0020]

FIG. 1 is a side sectional view showing an embodiment of a color laser printer as an image forming apparatus according to the present invention.

In FIG. 1, a color laser printer 1 includes a main body casing 2 and a paper 3 as a recording medium.
A paper feed unit 4 for feeding paper, an image forming unit 5 for forming an image on the paper 3, a paper discharge unit 6 for discharging the paper 3, and the like.

The paper feed unit 4 is disposed above the main body casing 2 and has a paper feed tray 7 for storing the paper 3.
A paper feed roller 8 for feeding the paper 3 stored in the paper feed tray 7; and a registration roller 9 provided downstream of the paper feed roller 8 in the transport direction of the paper 3.
In the paper feed tray 7, a paper pressing plate 11, one end of which is urged by a spring 10 toward a paper feed roller 8, is swingably supported. The paper 3 is stacked on the paper pressing plate 11 in a stacked manner, and the uppermost paper 3 is fed one by one by the rotation of the paper feed roller 8, and is conveyed from the paper feed roller 8. After a predetermined registration by the pair of registration rollers 9, the sheet 3 is sent to the image forming unit 5 described below.

The image forming unit 5 includes a scanner unit 12, a developing unit 13, and a fixing unit 14 as a fixing device.

The scanner unit 12 is provided at an upper part in the main body casing 2 and has a laser emitting unit (not shown),
A polygon mirror 15, which is driven to rotate, lenses 16 and 17, reflection mirrors 18 and 19, and the like. A laser beam based on predetermined image data emitted from a laser emitting section is reflected by the polygon mirror 15 as shown by an arrow. , The lens 16, the reflecting mirror 18, the lens 17, and the reflecting mirror 19 are sequentially passed or reflected to irradiate the surface of an endless belt 33 of the photosensitive belt 20 described later by high-speed scanning.

The developing unit 13 is disposed below the scanner unit 12 in the main body casing 2, and includes a photosensitive belt 20, a developing cartridge 21, and a scorotron type charger 2.
2, an intermediate transfer belt 23, a transfer roller 24, and the like.

The four developing cartridges 21 are provided corresponding to the respective colors of yellow, magenta, cyan, and black. The developing cartridges 21 are arranged in parallel with each other at predetermined intervals in the vertical direction while facing the photosensitive belt 20. It is arranged in a shape.

Each of the developing cartridges 21, that is, the yellow developing cartridge 21Y, the magenta developing cartridge 21M, the cyan developing cartridge 21C and the black developing cartridge 21K is formed in a rectangular cross section extending in the front-rear direction. The developing roller 25, the layer thickness regulating blade 26, the supply roller 27, and the toner storage chamber 28 are provided in this order. Each developing cartridge 21 is configured to be movable in a horizontal direction so that each developing roller 25 facing the photosensitive belt 20 can be selectively brought into contact with or separated from the surface of the photosensitive belt 20.

In each toner storage chamber 28, a positively chargeable non-magnetic one-component toner having each color of yellow, magenta, cyan and black is stored for each developing cartridge 28. A plurality of agitators 29 are provided in the front and rear sides 28 at predetermined intervals. Then, by rotating each agitator 29, the toner in the toner storage chamber 28 is removed.
The ink is circulated efficiently and supplied to the supply roller 27.

A supply roller 27 is rotatably disposed on the side of the toner storage chamber 28, and a developing roller 25 is rotatably disposed opposite to the supply roller 27. . The supply roller 27 and the developing roller 25 are in contact with each other so that each of them is compressed to some extent. The supply roller 27 has a metal roller shaft covered with a roller made of a conductive foam material. Further, the developing roller 25 has a metal roller shaft covered with a roller made of a conductive rubber material. A predetermined developing bias is applied to the developing roller 25. In the vicinity of the developing roller 25,
The layer thickness regulating blade 26 is provided so as to press on the developing roller 25.

The toner discharged from the toner storage chamber 28 is supplied to the developing roller 2 by the rotation of the supply roller 27.
5, the supply roller 27 and the developing roller 2
5, and the developing roller 25
The toner supplied above enters between the layer-thickness regulating blade 26 and the developing roller 25 with the rotation of the developing roller 25, where it is further triboelectrically charged to form a thin layer having a certain thickness. And is carried on the developing roller 25.

On the other hand, the photosensitive belt 20 is disposed on the side of each of the developing cartridges 21 and a first roller 30 provided slightly above the developing roller 21 of the uppermost yellow developing cartridge 92Y. Roller 30
A second roller 31 provided vertically below and slightly below the developing roller 25 of the black developing cartridge 21K located at the lowest position, and a halfway between the first roller 30 and the second roller 31, 1 roller 30
And a third roller provided forward of the second roller 31.
A roller 32 is provided, and the first roller 30, the second roller 31, and the third roller 32 are arranged in a substantially triangular shape.

An endless belt 33 having a positively charged photosensitive layer made of an organic photosensitive material or the like is wound around the outer periphery of the first roller 30, the second roller 31, and the third roller 32. , Can be moved in the direction of the arrow (clockwise). The endless belt 33 is disposed between the first roller 30 and the second roller 31 so as to contact the developing rollers 25 arranged in parallel in the vertical direction. The second roller 35 of the intermediate transfer belt 23 described later
And the intermediate transfer belt 23 is wound so as to come into contact therewith via an endless belt 37.

The scorotron charger 22 is disposed above the endless belt 33 between the first roller 30 and the third roller 32 of the photosensitive belt 20 at a predetermined interval. The scorotron-type charger 22 is a positive-charge scorotron-type charger that generates corona discharge from a charging wire such as tungsten, and is configured to uniformly positively charge the surface of the photosensitive belt 20. Have been.

The surface of the endless belt 33 is
After being uniformly positively charged between the first roller 30 and the third roller 32 by the scorotron-type charger 22,
Exposure is performed on the first roller 30 by high-speed scanning of a laser beam from the scanner unit 12 to form an electrostatic latent image based on predetermined image data. Next, a visible image is formed on the endless belt 33 by bringing the developing roller 25 of the developing cartridge 21 into contact with the endless belt 33 on which the electrostatic latent image is formed. That is, when each developing roller 25 comes into contact with the endless belt 33 on which the electrostatic latent image is formed, each developing roller 25
The positively charged toner carried on the surface is exposed to the laser beam on the electrostatic latent image formed on the endless belt 33, that is, the surface of the uniformly positively charged endless belt 33, and is exposed to the laser beam. The image is visualized by selectively adhering to the portion where is reduced, whereby the reversal development in each developing roller 25 is achieved.

The intermediate transfer belt 23 is disposed on the side of the photosensitive belt 20, and is a first roller provided downstream of the registration roller 9 in the transport direction of the paper 3 so as to face the transport path of the paper 3. A second roller 35 provided on the lower side of the rear of the first roller 34 and opposed to an endless belt 33 between the second roller 31 and the third roller 32 of the photosensitive belt 20; A third roller 36 provided on the lower front side at a predetermined distance from the roller 35, and the first roller 34 and the second roller 35
And the third roller 36 are arranged in a substantially triangular shape. An endless belt 37 is wound around the outer periphery of the first roller 34, the second roller 35, and the third roller 36. The endless belt 37 contacts the endless belt 33 of the photosensitive belt 20 on the second roller 35. In this state, it can be moved in the direction of the arrow (counterclockwise). As the material of the endless belt 37, a resin such as conductive polycarbonate or polyimide is used. And the photosensitive belt 2
The visible image formed on the zero endless belt 33 is transferred onto the endless belt 37 of the intermediate transfer belt 23 on the second roller 35 of the intermediate transfer belt 23.

Then, a visible image is formed on the endless belt 33 of the photosensitive belt 20 for each color, and the visible image is sequentially formed.
A color image is formed by overlapping the intermediate transfer belt 23 on the endless belt 37. That is,
First, the uppermost yellow developing cartridge 21
When only the Y developing roller 25 is brought into contact with the endless belt 33 of the photosensitive belt 20, a visible image is formed on the endless belt 33 by the yellow toner, and this visible image is formed by the second roller 31 and the third roller 32. And the endless belt 37 of the intermediate transfer belt 23
Transcribed above. Next, when only the developing roller 25 of the second magenta developing cartridge 21M is brought into contact with the endless belt 33 of the photosensitive belt 20, a visible image is formed on the endless belt 33 by the magenta toner. When the visual image passes between the second roller 31 and the third roller 32, the visual image is transferred onto the endless belt 37 of the intermediate transfer belt 23 on which the yellow toner image has already been transferred. Thereafter, the same operation is performed for the cyan toner of the cyan developing cartridge 21C.
This is repeated with the black toner of the black developing cartridge 21 </ b> K, whereby a color image is formed on the endless belt 37 of the intermediate transfer belt 23.

The transfer roller 24 is rotatably disposed above the intermediate transfer belt 23 and at a position facing the first roller 34 of the intermediate transfer belt 23 via the paper 3. The transfer roller 24 has a metal roller shaft covered with a roller made of a conductive rubber material, and a predetermined transfer bias is applied. The color image formed on the intermediate transfer belt 23 is collectively transferred to the paper 3 while the paper 3 passes between the endless belt 37 of the intermediate transfer belt 23 and the transfer roller 24, and thereafter, the transferred paper is 3 is transported to the fixing unit 14.

The fixing unit 14 includes an intermediate transfer belt 23
, The heating roller 38 and the heating roller 38, which will be described in detail later.
A heating belt 39 wound around the heating roller 38, a pressing roller 40 disposed opposite to the heating roller 38 and the heating belt 39,
A halogen lamp 41 is provided as a light source for irradiating light to heat the heating roller 38 and the heating belt 39, and a reflection plate 42 and the like are provided. Then, the color image transferred onto the sheet 3 in the developing unit 13 is thermally fixed while the sheet 3 passes between the heating belt 39 and the pressing roller 40.

The paper discharge unit 6 is disposed downstream of the fixing unit 14 in the transport direction of the paper 3, and has a paper discharge roller 43 and a paper discharge tray 44. Then, the sheet 3 on which the color image is thermally fixed by the fixing unit 14 is formed.
Is discharged onto a discharge tray 44 by a pair of discharge rollers 43.

The color laser printer 1 has
A transfer-side cleaner 48 is provided for collecting the toner remaining on the endless belt 37 of the intermediate transfer belt 23 after the transfer to the paper 3. Transfer side cleaner 48
Is the third roller 3 below the intermediate transfer belt 23.
6, a collection box 49 having an opening formed in the upper part thereof, and a cleaning blade 50 provided in the opening of the collection box 49. The toner remaining on the endless belt 37 of the intermediate transfer belt 23 is scraped off by the cleaning blade 50 and collected in the collection box 49.

The color laser printer 1 has
A photosensitive-side cleaner 45 is provided for collecting toner remaining on the endless belt 33 of the photosensitive belt 20 after transfer to the endless belt 37 of the intermediate transfer belt 23. The photosensitive-side cleaner 45 is disposed on the side of the photosensitive belt 20 so as to face the third roller 32, and is provided at a collection box 46 having an opening formed at a side portion, and provided at an opening of the collection box 46. And a cleaning blade 47 that can be used. The toner remaining on the endless belt 33 of the photosensitive belt 20 is scraped off by the cleaning blade 47 and collected in the collection box 46.

In the color laser printer 1, as shown in FIG. 2, the fixing unit 14 is configured as follows. That is, the fixing unit 14
As described above, the heating roller 38, the heating belt 39, the pressing roller 40, the halogen lamp 41, and the reflection plate 42 are provided.

The heating roller 38 includes a metal roller shaft 51.
And a rubber roller 5 made of silicon rubber or fluorine rubber
2 are coated. When forming a color image,
Since the toner layer formed on the paper 3 becomes thicker, the image may be crushed when pressed by a metal heating roller. Therefore, when the rubber roller 52 is used, a good color image with less crushing can be formed.

In the heating roller 38, a rubber roller 52 is subjected to light absorption processing. As the light absorption processing, processing for coloring the roller 52, processing for roughening the surface of the roller 52, and the like are used. If the roller 52 is colored, light can be well absorbed at the colored wavelength, and if the surface of the roller 52 is roughened,
The surface area can be increased, and the light can be efficiently absorbed on the light receiving surface. Further, if the surface of the roller 52 is roughened, frictional resistance between the heating belt 39 and the heating belt 39 increases, and slip between the heating belt 39 and the heating belt 39 is prevented.
Reliable drive transmission can be ensured.

As the coloring treatment, the roller 52 itself may be formed of a light absorbing material, or the surface of the roller 52 may be painted. When the roller 52 itself is formed of a light-absorbing material, for example, it may be formed by blending a coloring agent such as carbon black with silicon rubber or fluorine rubber. When painting the surface of the roller 52, for example, the surface of the roller 52 may be painted in black or the like. Note that a coat layer containing a colorant such as carbon black may be formed on the surface of the roller 52.

The surface roughening may be performed by blasting or chemical treatment. When blasting is performed, for example, the surface of the roller 52 may be roughened by sand blasting or the like. In the case of performing a chemical treatment, for example, the surface of the roller 52 may be roughened using an acid or the like. In the roughening of the roller 52, the surface roughness Rz of the surface is preferably set to 0.1 μm or more.

The roller 52 of the heating roller 38 may be subjected to a combination of these light absorbing treatments. More specifically, the roller 52 has its surface blackened after the blast treatment. Painted.

The heating belt 39 has an endless belt shape, and has an outer periphery formed by a heating roller 38 and two guide rollers 53 and 54 rotatably provided below the heating roller 38 at a predetermined interval from each other. , And is configured to move around the heating roller 38 and the two guide rollers 53 and 54 in the direction of the arrow (counterclockwise) by driving the heating roller 38. As a result, the outer surface of the heating belt 39 is pressed against the pressing roller 40 and contacts the toner on the paper 3 when the paper 3 is fixed, and the inner surface thereof is heated by the heating roller 38 and the two guide rollers. It comes into contact with 53 and 54.

The heating belt 39 is made of polyimide or PF
It is made of a rubber material such as A (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and has been subjected to a light absorption treatment similarly to the roller 52 of the heating roller 38. That is, the light absorption processing uses the same processing as the above-described light absorption processing of the roller 52 of the heating roller 38, such as the processing of coloring the heating belt 39 and the processing of roughening the surface of the heating belt 39. If the heating belt 39 is colored, light can be well absorbed at the colored wavelength, and if the surface of the heating belt 39 is roughened, the surface area can be increased and the light receiving surface can be efficiently used. Can be absorbed.

As the coloring treatment, as described above, for example, a heating agent 39 is formed by mixing a coloring agent such as carbon black with polyimide or PFA, and the heating belt 39 itself is formed of a light-absorbing material. What is necessary is just to paint the surface of 39 with black etc. When PFA is used as the material of the heating belt 39, for example,
It can also be colored by sodium naphthalene treatment or the like. When the surface of the heating belt 39 is colored, at least the inner surface thereof may be colored, and the outer surface that comes into contact with the paper 3 does not need to be particularly colored. In order to color only the inner surface, more specifically, for example, only a coat layer in which a coloring agent such as carbon black is blended, or a coat layer treated with sodium naphthalene, Alternatively, only the inner surface of the heating belt 39 may be painted in black or the like.

In the same manner as described above, the surface roughening treatment may be, for example, blasting by sandblasting or chemical treatment using an acid or the like. In the surface roughening treatment of the heating belt 39, only the inner surface thereof may be roughened so that the surface roughness of the inner surface with respect to the outer surface of the heating belt 39 may be larger.
That is, when the outer surface of the heating belt 39 is roughened, when the toner is brought into contact with the toner on the paper 3 and fixed, the fixing property is affected, and a fixing defect may occur. Therefore, if only the inner side surface of the heating belt 39 is roughened, light is efficiently absorbed on the inner side surface while ensuring good fixation of the toner without affecting the fixability of the toner on the paper 3. be able to. Further, if the inner side surface is roughened, the frictional resistance between the heating roller 38 and the heating roller 38 increases, so that slippage between the heating roller 38 and the heating roller 38 can be prevented, and reliable drive transmission can be ensured. In the roughening of the heating belt 39, it is preferable that the surface roughness Rz of the surface be 0.1 μm or more.

The heating belt 39 may be subjected to a combination of these light absorbing treatments. More specifically, the heating belt 39 has a black inner surface after the blast treatment. It is painted on.

The pressing rollers 40 are arranged to face each other with the heating belt 39 interposed therebetween, and are configured to press the paper 3 from the surface of the paper 3 opposite to the side on which the toner layer is formed when fixing the paper 3. The pressing roller 40 has an aluminum pipe member 55 covered with a rubber roller 56 made of silicon rubber, fluorine rubber, or the like. In the case of forming a color image, the toner layer formed on the paper 3 becomes thicker, so that pressing the toner contact surface with a metal pressing roller may cause image collapse. Therefore, when the rubber roller 56 is used, a good color image with less crushing can be formed.

The halogen lamp 41 is disposed substantially at the center inside the heating belt 39 wound around the heating roller 38 and the two guide rollers 53 and 54.
The heating belt 39 is configured to irradiate light from the inside to heat them.

The reflecting plate 42 is arranged around the halogen lamp 41 so as to cover the halogen lamp 41, and one side of the reflecting plate 42 is a portion where the heating belt 39 is in contact with and wound around the heating roller 38. Open to the public. Therefore, light emitted from the halogen lamp 41 is reflected by the reflection plate 42, and more light is emitted from the heating belt 39 and the heating roller 38 immediately upstream of the contact portion between the heating belt 39 and the pressing roller 40. Irradiated towards the site.

The light emitted from the halogen lamp 41 is applied to the inner surface of the heating belt 39 and the heating roller 38.
However, since the inner surface of the heating belt 39 and the surface of the heating roller 38 have been subjected to light absorption processing for absorbing the light as described above,
The irradiated light is efficiently absorbed at each light receiving surface. Therefore, the heating belt 39 and the heating roller 38
Is quickly heated by the light from the halogen lamp 41 and can quickly reach the fixing temperature. Therefore, when such a fixing unit 14 is provided, it is possible to secure a quick fixing operation with a short warm-up time. Can be achieved.

In particular, in the color laser printer 1, since the toner layer formed on the paper 3 becomes thick in order to form a color image, the roller 52 of the heating roller 38 is heated to prevent the image from being crushed. Although the belt 39 and the roller 56 of the pressing roller 40 are made of rubber, by performing the above-described light absorption processing on the roller 52 of the heating roller 38 and the heating belt 39, the efficiency of absorbing these lights is improved. As a result, the rubber defect that the temperature is hardly increased by heating is effectively solved. Therefore, the color laser printer 1 can form a good color image with little crushing at the time of fixing, and realizes quick image formation by performing a quick start from power-on.

In the fixing unit 14, the halogen lamp 41 is arranged inside the heating belt 39 so that only the inner surface of the heating belt 39 needs to be subjected to the light absorption processing. Problems such as defective fixing that occur when the outer surface of the heating belt 39 that comes into contact with the toner on the paper 3 are roughened are also effectively eliminated.

In the above description, the heat roller 38 and the heating belt 39 are subjected to various light absorption processes such as a process of forming with a light absorbing material, a coating process, a blast process, and a chemical process, so that the light is absorbed. Although the absorption efficiency is increased, these treatments may be appropriately selected depending on the material, purpose, and use of the heating roller 38 and the heating belt 39, and at least one of these treatments is subjected to light absorption treatment. Just do it. In the above description, both the heating roller 38 and the heating belt 39 are subjected to the light absorption processing. However, depending on the purpose and application, only one of them may be subjected to the light absorption processing.

In the above description, such a fixing unit 14 has been described as an example applied to the color laser printer 1.
4 may be applied to a laser printer that forms a monochrome image. In a laser printer that forms a monochrome image, the toner layer formed on the paper 3 is thin, and it is not necessary to consider the collapse of the image. For example, the heating roller 38 is made of a metal having higher thermal efficiency. Alternatively, the surface of the metal heating roller 38 may be subjected to various types of light absorption processing such as the above-described coating processing, blast processing, and chemical processing.

[0061]

As described above, according to the first aspect of the present invention, at least one of the heating belt and the heating roller receives light irradiated from the light source, and receives light irradiated from the light source. Since the light is efficiently absorbed, a quick fixing operation with a short warm-up time can be secured. Further, in the case of the heating belt, it is not necessary to perform the light absorption processing on the surface which is in contact with the recording medium in opposition to the pressing roller. In addition, good fixing of the developer can be achieved.

According to the second aspect of the present invention, a quick fixing operation with a short warm-up time can be reliably achieved by various processes.

According to the third aspect of the present invention, since the surface area of the light receiving surface of the heating belt for receiving the light from the light source is large, the irradiated light is efficiently absorbed, and the warm-up is short and quick. A proper fixing operation can be further ensured. Also, since the surface opposite to the light receiving surface does not receive light, there is no need to increase the surface roughness, and the surface roughness may be determined by giving priority to the fixability of the developer. There is little influence on the fixing property of the above developer, and good fixing of the developer can be achieved. Also, if the surface roughness of the light receiving surface of the heating belt is large, the frictional resistance between the heating roller and the heating roller is increased, so that the slip between the heating belt and the heating roller is prevented, and the heating belt is reliably connected to the heating belt. The transmission of a proper drive can be ensured.

According to the fourth aspect of the present invention, a quick fixing operation with a short warm-up time can be ensured, so that a quick start can be performed from the time of turning on the power, and a quick image formation can be achieved. .

According to the fifth aspect of the present invention, since the fixing device having a short warming-up and capable of securing a quick fixing operation is provided, the heating roller and the heating belt are made of rubber and are crushed. It is possible to form a good color image with a small number of images, and to realize a quick image formation by performing a quick start from power-on.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a main part of an embodiment of a color laser printer as an image forming apparatus of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the fixing unit of the color laser printer shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 color laser printer 14 fixing unit 38 heating roller 39 heating belt 40 pressing roller 41 halogen lamp

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 3/00 335 H05B 3/00 335 345 345 F F-term (Reference) 2H033 AA11 AA30 BA11 BB04 BB18 3J103 AA02 AA13 AA14 AA32 AA51 AA61 AA72 BA02 BA16 BA41 EA20 FA01 FA20 FA23 GA02 GA52 GA58 HA04 HA05 HA06 HA11 HA15 HA31 HA52 HA53 HA54 3K058 AA02 BA18 DA02 EA00 GA06

Claims (5)

[Claims] 1. A developer formed on a recording medium, comprising: a heating roller; a heating belt wound around the heating roller; and a pressing roller opposed to the heating roller with the heating belt interposed therebetween. A light source for irradiating the heating belt and the heating roller with light is provided on the heating roller side with respect to the heating belt, and the heating belt and the heating roller are provided. Wherein at least one of the fixing devices is subjected to a light absorbing process for absorbing the light emitted from the light source on a surface receiving the light emitted from the light source. 2. A heat receiving surface of the heating belt and the heating roller, which receives light from the light source, is formed by a light absorbing material, a coating process, a blast process, and a chemical process. The fixing device according to claim 1, wherein the fixing device is used. 3. A surface of the heating belt that receives light from the light source is formed so as to have a larger surface roughness than a surface of the heating belt that does not receive light from the light source. The fixing device according to claim 1, wherein: 4. An image forming apparatus comprising the fixing device according to claim 1. 5. The image forming apparatus according to claim 4, wherein the image forming apparatus is configured to be capable of forming a color image.