JPH05158311A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To stabilize the static charge characteristic of a photosensitive body and the characteristic of conductive magnetic toner by providing a cooling device for cooling a dielectric belt on which a toner image on the photosensitive body is transferred near the dielectric belt. CONSTITUTION:A pressuring roller 12 which rotates while it causes pressing force at act on a heating device 10 through the dielectric belt 8 is provided on the heating device 10, so that a transfer paper fed by a recording material feeding means 14 is nipped by a press-contacting part between the belt 8 and the roller 12. The cooling device 24 for cooling the belt is provided below the belt 8, and air is supplied to the above belt 8 by the cooling fan 24. Thus, the belt 8 is kept at <= about 40 deg.C even though it is heated with the transfer paper by the heating device 10 which heats to melt the conductive magnetic toner. Therefore, the temperature of the photosensitive drum 1 is prevented from rising and becoming unstable, and the electrostatic charging characteristic of the drum 1 is not influenced by the heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus for forming an image by forming a toner image on the surface of a photoconductor and then transferring and fixing the toner image on a recording material.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic method based on the application of the Carlson process has been widely used for image formation using toner. The principle will be described with reference to FIG. 8 by taking as an example the positive development method used in a copying machine, which is an electrophotographic apparatus, and the apparatus adopting the Carlson process is shown in FIG. A charging device 32, an exposing device 33, and a developing device 3 are provided around a photoconductor drum 31 having a photosensitive layer on the inside.
4, transfer device 35, fixing device 36, cleaner 37, static eliminator 3
8 are sequentially provided.

In the above structure, first, the surface of the photosensitive drum 31 is uniformly charged by the charger 32 in a dark place. Next, the exposure device 33 irradiates light to remove the charged electric charge in the exposed portion to form an electrostatic latent image. Then, the electrostatic latent image is charged with the toner 39 having a polarity opposite to that of the charge on the photosensitive drum 31 in the developing device 34.
As a result, the visible image is formed by the toner 39. After that, the recording material 40 is superposed on the visible image, and a corona discharge is applied from the back side of the recording material 40 by the transfer device 35 to give an electric charge having a polarity opposite to that of the toner 39, whereby the toner image is transferred to the recording material 40. .. The transferred toner image is fixed on the recording material 40 by the heat and pressure of the fixing device 36 and becomes a permanent image. On the other hand, the residual toner 39 a remaining on the photosensitive drum 31 without being transferred to the recording material 40 is collected by the cleaner 37.
Are removed by. Further, the electrostatic latent image on the photoconductor drum 31 is neutralized by the light of the static eliminator 38, and then the process starting from the charging by the charger 32 is repeated again, and continuous image formation is performed.

By the way, in the electrophotographic apparatus to which the Carlson process is applied as described above, a corona discharger is usually used for charging the photosensitive drum 31 and transferring the toner 39 to the recording material 40. This corona discharger requires a high applied voltage of several kV and is easily affected by environmental changes such as changes in the charge amount on the surface of the photosensitive drum 31 due to changes in temperature.
In addition, ozone is generated during corona discharge, which causes environmental hygiene problems.

Therefore, the present inventor has previously proposed an electrophotographic apparatus which does not require the above-mentioned corona charging (Japanese Patent Application No. 3-240977). 2, which is an explanatory diagram of the present invention,
3 and FIG. 3, the photoconductive layer 1 is viewed from the front side.
c, the transparent conductive layer 1b has the photoconductor 1 which is sequentially provided on the transparent support 1a, and a voltage is applied to the conductive magnetic toner T on the toner holder 5 to obtain the conductive magnetic toner. At T, the surface of the photoconductor 1 is charged, and the exposure device 7 provided in the toner holder 5 performs exposure according to the writing signal from the transparent support 1a side, and at the exposure position, the conductive magnetic The electrophotographic apparatus forms a toner image on the photoconductor 1 by bringing the toner T into contact therewith.

In the above electrophotographic apparatus, the toner image formed on the photoconductor 1 is transferred onto the dielectric belt 8 arranged above the photoconductor 1, and the toner image is transferred onto the dielectric belt 8. The formed toner image is transferred onto the transfer paper P conveyed from the recording material conveying means 14 located above the dielectric belt 8,
When the dielectric belt 8 and the transfer paper P are conveyed while being overlapped between the pressure roller 12 and the heating device 10, the heating device 10 heats and melts the toner to transfer the toner.
It is designed to be fixed.

[0007]

However, in the electrophotographic apparatus as described above, the temperature of the dielectric belt 8 rises at the time of transferring and fixing the toner image on the transfer paper P, which is accompanied by the temperature rise. The temperature of the photoconductor 1 also rises, and the temperature of the photoconductor 1 becomes unstable and non-uniform due to the size of the transfer paper P and the difference in the number of continuously transferred sheets, so that a good transfer image cannot be obtained. Has the problem. That is, when the toner image formed on the dielectric belt 8 is transferred, the dielectric belt 8 is heated by the heating device 10, so that if the size of the transfer paper P, the number of continuous transfer sheets, etc. are different, As the temperature of the body belt 8 rises, the temperature distribution and the degree of rise change. Then, after the toner image is transferred, the dielectric belt 8 comes into contact with the photoconductor 1 again in a state where the temperature has risen, and the toner image is transferred. As the temperature rises, the temperature of the photoconductor 1 becomes unstable and the temperature becomes uneven.

When the temperature of the photosensitive member 1 exceeds the softening point of the conductive magnetic toner T of 60 to 70 ° C., the conductive magnetic toner T is softened and the toner characteristics are destabilized. It is impossible to form a fine toner image. If the temperature rise of the photoconductor 1 is constant below the softening point of the conductive magnetic toner T, it does not significantly affect the formation of the toner image on the photoconductor 1, but the photoconductive layer 1c made of Se. With respect to the photoconductor 1 having the above, since Se crystallizes at 40 ° C., it is necessary to maintain the temperature at 40 ° C. or less.

Since the temperature instability and temperature nonuniformity of the photosensitive member 1 affect the charging characteristics of the photosensitive member 1, the adhered amount of the conductive magnetic toner T is not stable. No good toner image can be formed on No. 1.

Therefore, an object of the present invention is to stabilize the charging characteristics of the photoconductor 1 and the toner characteristics of the conductive magnetic toner T by cooling the temperature of the dielectric belt 8.

[0011]

In order to solve the above problems, an electrophotographic apparatus according to claim 1 of the present invention includes a dielectric belt to which a toner image formed on a photoconductor is transferred, A heating device for heating and melting the toner of the toner image formed on the dielectric belt is provided, and the heating is performed by sandwiching the dielectric belt and the recording material fed over the dielectric belt. An electrophotographic apparatus is provided with a pressing means for pressing the overlapping portion of the dielectric belt and the recording material toward the heating device at a position facing the device, wherein the dielectric material is provided near the dielectric belt. It is characterized in that a cooling device for cooling the belt is provided.

In order to solve the above problems, the electrophotographic apparatus according to claim 2 is the electrophotographic apparatus according to claim 1, wherein the cooling device is provided inside a dielectric belt. Is characterized by.

In order to solve the above-mentioned problems, an electrophotographic apparatus according to a third aspect of the present invention includes a dielectric belt to which a toner image formed on a photoconductor is transferred, and a dielectric belt formed on the dielectric belt. A heating device for heating and melting the toner of the toner image being formed is provided, and at a position facing the heating device with the dielectric belt and the recording material fed superposed on the dielectric belt interposed therebetween. An electrophotographic apparatus provided with pressing means for pressing an overlapping portion of a dielectric belt and a recording material toward the heating device, wherein the dielectric belt is provided with tension and driving force. A plurality of rollers are provided, and at least one of the rollers arranged between the heating device downstream side and the photoconductor upstream side is made of metal.

According to a fourth aspect of the present invention, in order to solve the above problems, in the electrophotographic apparatus according to the third aspect, the bearing supporting the roller made of the metal is made of metal. It is characterized by being formed.

[0015]

According to the structure described in claim 1, when the toner image formed on the dielectric belt is transferred and fixed on the transfer paper, the dielectric belt heated by the heating device is the dielectric belt. It is designed to be cooled by a cooling device provided in the vicinity. For this reason, when the toner image formed on the photoconductor is transferred onto the dielectric belt, they come into contact with each other, so that the temperature of the photoconductor rises and the temperature becomes unstable and non-uniform. Is suppressed. As a result, the charging characteristics of the photoconductor and the toner characteristics of the toner are stabilized, and good transfer images can be obtained.

According to the second aspect of the invention, since the cooling device is provided inside the dielectric belt, the same effect as described above can be obtained, and the air blown from the cooling device is generated. It is possible to prevent the area other than the dielectric belt from reaching, and it is possible to save space without requiring a new space for installing a cooling device.
As a result, it is possible to reduce the size of the device.

According to the third aspect of the present invention, the roller for rotating the dielectric belt arranged between the heating device downstream side of the dielectric belt and the photosensitive member upstream side has a heat capacity of the dielectric belt. Since it is made of a metal that has an extremely large heat capacity and good thermal conductivity as compared with, when heat is conducted from the dielectric belt to the roller when the dielectric belt comes into contact with the roller made of metal. The temperature of the dielectric belt is lowered, and the dielectric belt comes into contact with the photoreceptor in the lowered temperature. Therefore, the same effect as described above can be obtained without increasing the number of parts.

According to the structure of claim 4, since the bare ring of the metal roller is made of metal,
The heat diffusivity is improved, a further cooling effect can be expected, and the same effect as described above can be obtained.

[0019]

【Example】

[Embodiment 1] FIG. 1 through FIG.
The explanation is based on the following. As shown in FIG. 1, the electrophotographic apparatus according to this embodiment includes a cylindrical photosensitive drum (photosensitive member) 1 rotatable in the direction A in the apparatus. Developing device 2
However, an exposure device 7 is arranged inside the photosensitive drum 1, and a dielectric belt 8 is arranged above the photosensitive drum 1.

As shown in FIG. 3, the photoconductor drum 1 has an optically transparent cylindrical transparent support 1a on the surface thereof.
A transparent conductive layer 1b made of a sputtered film such as In ₂ O ₃ or SnO ₂ ,
A photoconductive layer 1c made of a photoconductive material such as Se, ZnO, CdS, or amorphous Si is sequentially laminated.
In this embodiment, the transparent conductive layer 1b has a film thickness of
An In ₂ O ₃ layer having a thickness of 0.5 μm is formed, and an amorphous Si layer having a thickness of 3 μm is formed as the photoconductive layer 1c.

The developing device 2 includes a developing tank 3 for storing a conductive magnetic toner T as a developer, a stirring roller 4 rotatably provided in the developing tank 3 for stirring the conductive magnetic toner T, and a developing device. Photoreceptor drum 1 in opening 3a of tank 3
A toner holder 5 arranged at a position facing the
And a doctor blade 6 fixedly provided at a position below the toner holder 5 in the opening 3a.

The toner holder 5 extends along the longitudinal direction of the photosensitive drum 1 and has a magnetic roller 5a in which magnets of N polarity and S polarity are alternately arranged in the circumferential direction, and a non-magnetic member, for example. The developing sleeve 5b is made of aluminum or martensitic stainless steel and is provided so as to cover the outer peripheral surface of the magnetic roller 5a. The toner holding member 5 holds the conductive magnetic toner T on the surface of the developing sleeve 5b by the alternating magnetic field generated by the rotation of the magnetic roller 5a in the direction B in the apparatus, and rotates the magnetic roller 5a in the rotating direction. B'in the opposite direction to the B direction
It is designed to be conveyed in the direction. Further, the doctor blade 6 adjusts the carrying amount of the conductive magnetic toner T which is held on the surface of the developing sleeve 5b and carried in the B'direction as described above.

The conductive magnetic toner T is prepared by kneading resin such as styrene-acryl copolymer with magnetic powder such as iron powder and ferrite, carbon black, etc., and pulverizing it to several tens to several tens of μm. It is composed of powder.

The exposure device 7 is composed of an LED array in which a short focus lens is combined with a light emitting diode, and the direction of the developing device 2 is changed in accordance with an image pattern signal from an exposure control device (not shown). The irradiation light is directed to the photoconductive layer 1c through the transparent support 1a of the photosensitive drum 1 and the transparent conductive layer 1b.

The dielectric belt 8 is formed into an endless belt shape by using a film material mainly composed of a polyimide resin having excellent mechanical strength and high heat resistance.
The dielectric belt 8 is, as shown in FIG. 1, a transfer roller 9 disposed above the photosensitive drum 1, and a transfer roller 9 disposed on the left side of the transfer roller 9 in the drawing and slightly above. The heating device 10 and the tension roller 11 arranged on the lower left side of the heating device 10 are wound around the three members 9, 10 and 11 from the outside, and Between the photosensitive drum 1 and the transfer roller 9, the photosensitive drum 1 and the transfer roller 9 are provided.
It is sandwiched by and.

A film-shaped polyimide resin is used as the material of the dielectric belt 8, but the material is not particularly limited to this material, and the conductive magnetic toner T is transferred at least as described later. Any surface may be used as long as it has an insulating property. For example, a metal belt such as an electroformed nickel belt as a base material may be coated with fluorine. Although the thickness of the dielectric belt 8 is not particularly limited, it is 10 μm to 200 μm in consideration of thermal conductivity and mechanical strength.
The thickness is preferably about the same, and the surface may be roughened so that the gloss of the image is appropriate.

As will be described later, the heating device 10 is for heating and melting the conductive magnetic toner T transferred onto the surface of the dielectric belt 8, and a planar Mo-based heating resistor ( Printing a sheet heating element) 10a,
It is composed of a ceramic heater on which a glass coat is printed and laminated. Then, the heating device 10 is
By energizing the heating resistor 10a, the temperature is quickly raised to a predetermined heating temperature, and the heating surface is arranged so as to be in direct contact with the surface of the dielectric belt 8.

A pressure roller (pressing means) 12 that rotates while applying a pressing force in a direction toward the heating device 10 via the dielectric belt 8 is provided on the upper side of the heating device 10.
The pressure roller 12 is configured to sandwich the transfer paper P as a recording material conveyed by the recording material conveying means 14 described later at the pressure contact portion with the dielectric belt 8. Is becoming

Below the dielectric belt 8,
An axial flow type cooling fan (cooling device) 24 for cooling the dielectric belt 8 is provided, and the cooling fan 24 is provided.
The dielectric belt 8 is cooled by blowing air toward the dielectric belt 8 located above. Although not shown, the cooling fan 24
The side plate of the electrophotographic apparatus on the side of is provided with a ventilation hole for taking in outside air while discharging it.
The outside air can pass through the gap on the side plate side. Although the cooling fan 24 is formed in an axial flow type, it is not particularly limited to this shape and may be a cross flow type or a floor type. Further, the formation position of the ventilation hole is not limited to the side plate of the electrophotographic apparatus, but may be formed on the bottom plate or the like.

In addition, the electrophotographic apparatus of this embodiment has the structure shown in FIG.
As shown in FIG. 3, a stepping motor 13 that is a drive source of the apparatus, a recording material conveying unit 14 that conveys the transfer sheet P to a pressure contact portion between the dielectric belt 8 and the pressure roller 12, and a transfer sheet P from inside the apparatus. A sheet discharging unit 21 for discharging the sheet is provided.

The recording material conveying means 14 is arranged above the photoconductor drum 1, the developing device 2 and the dielectric belt 8 and its constituent members are from a transfer paper supply opening (not shown). A transport guide plate 15 that forms a transport path that connects the dielectric belt 8 and the pressure roller 12 to the pressure contact portion.
A paper feed detection actuator 16, a paper feed detection switch 17, a paper feed roller 18 arranged near the transfer paper supply opening, a registration roller 19 arranged in the middle of the path of the conveyance guide plate 15, and a registration roller A registration solenoid 20 that controls the rotation of the roller 19 is provided.

The paper output means 21 is disposed on the left side of the pressure contact portion between the dielectric belt 8 and the pressure roller 12, and its constituent member is the pressure contact between the dielectric belt 8 and the pressure roller 12. A sheet output guide plate 22 that forms a sheet output path that connects the sheet to a transfer sheet discharge opening (not shown), and a sheet output detection actuator 23 disposed near the pressure contact portion between the dielectric belt 8 and the pressure roller 12. The paper ejection guide plate 22 is provided with a paper ejection roller 25 disposed on the terminal side.

Regarding the operation of the electrophotographic apparatus having the above structure,
It will be described next.

First, the transfer paper feeding means (not shown)
When a sheet of transfer paper (transfer material) P is fed from the transfer paper supply opening, the leading end of the transfer paper P pushes up the paper-feed detection actuator 16 so that the paper-feed detection switch 17 supplies the transfer paper P. The detection is transmitted to the stepping motor 13 and a sheet detection signal is transmitted to the stepping motor 13, and the stepping motor 13 as a drive source is rotationally driven.

Next, the rotation of the stepping motor 13 is transmitted to the paper feed roller 18 via a rotation transmission mechanism (not shown), whereby the paper feed roller 18 is rotated, and with the rotation of the paper feed roller 18, The transfer paper P is the registration roller 1
9 is transported.

The transfer sheet P conveyed to the registration rollers 19 as described above is once in a state where the conveyance is stopped by the rotation of the registration rollers 19 being controlled by the registration solenoid 20. At this time, the sheet feeding rollers 18 and 18 are in a state of sandwiching the rear end side of the transfer sheet P, and since the resistance of the roller surface is small, the transfer sheet P is stopped when the transfer sheet P is stopped. It is a slipped state on both sides.

Next, the developing process of the conductive magnetic toner T will be described with reference to FIGS.

First, the conductive magnetic toner T stored in the developing tank 3 is held on the surface of the developing sleeve 5b by the alternating magnetic field generated by the rotation of the magnetic roller 5a in the B direction, as shown in FIG. At the same time, it is conveyed on the surface of the developing sleeve 5b in the B'direction which is the opposite direction to the A direction which is the rotation direction of the photosensitive drum 1. At this time, at the contact portion between the conductive magnetic toner T held on the surface of the developing sleeve 5b and the photosensitive drum 1, a potential difference of several tens of V is applied between the developing sleeve 5b and the transparent conductive layer 1b. Charge is injected from the developing sleeve 5b to the photosensitive drum 1 through the conductive magnetic toner T, and the surface of the photosensitive drum 1 is charged to substantially the same potential as the developing sleeve 5b.

The conductive magnetic toner T contacted with the photoconductor drum 1 as described above has the same potential on the surface of the photoconductor drum 1 and the developing sleeve 5b, whereby the magnetic roller 5a.
It is not attached to the photosensitive drum 1 because it is predominantly affected by the magnetic force generated.

Next, as shown in FIG. 4, the photosensitive drum 1
When the LEDs corresponding to the image pattern of the original are sequentially selected and exposed by the exposure device 7 immediately before the conductive magnetic toner T is separated from the conductive magnetic toner T or at a portion C in the vicinity thereof, the light is injected onto the surface of the photosensitive drum 1. The accumulated charge is neutralized, and a potential difference is generated between the surface of the photosensitive drum 1 and the developing sleeve 5b.

After that, due to the potential difference as described above, charge is again injected from the developing sleeve 5b to the photosensitive drum 1 through the conductive magnetic toner T. However, before the charge is sufficiently injected, the charge is transferred to the photosensitive drum 1. Conductive magnetic toner T
Therefore, as shown in FIG. 5, the conductive magnetic toner T is subjected to the action of an electric field acting between the developing sleeve 5b and the surface of the photosensitive drum 1 in the state of being charged, and the magnetic force of the magnetic roller 5a is exerted. Is shaken off and adhered to the surface of the photosensitive drum 1, and is developed on the surface of the photosensitive drum 1 as a toner image corresponding to the image pattern.

The toner image developed on the surface of the photosensitive drum 1 as described above is passed through the dielectric belt 8 by applying a voltage having a polarity opposite to the injected charge of the toner image to the transfer roller 9. It is transferred onto the surface of the dielectric belt 8 at the pressure contact portion between the photosensitive drum 1 and the transfer roller 9. On the other hand, CPU (Ce
When the registration solenoid 20 outputs a signal to the registration solenoid 20, the rotation stop state of the registration roller 19 described above is released, and the transfer paper P is conveyed to the pressure contact portion between the dielectric belt 8 and the pressure roller 12. ..

Then, the dielectric belt 8 and the transfer paper P on which the above toner image is transferred are connected to the heating device 10 and the pressure roller 1.
By being superposed and conveyed between the two sheets, the transfer and fixing of the toner image on the transfer sheet P are simultaneously performed. That is, when the transfer paper P is sent out while being pressed against the dielectric belt 8 and the pressure roller 12, the conductive magnetic toner T heated and melted by the heating device 10 is transferred to the dielectric belt 8. Since the surface has better releasability than the transfer paper P, most of the conductive magnetic toner T on the surface of the dielectric belt 8 is transferred and fixed onto the transfer paper P.

After that, the transfer paper P on which the above-mentioned toner image has been transferred and fixed is pushed up by the paper output detection actuator 23, and is discharged from the apparatus through the transfer paper discharge opening by the rotation of the paper discharge roller 25. Then, after a predetermined time, the heating resistor 10a of the heating device 10 is not energized and the driving of the stepping motor 13 is stopped, and the series of operations described above is ended.

As described above, in the electrophotographic apparatus of this embodiment, the cooling fan 24 is provided below the dielectric belt 8. Therefore, when the toner image is transferred onto the transfer paper P, even if the dielectric belt 8 is heated at the same time as the transfer paper P by the heating device 10 for heating and melting the conductive magnetic toner T, the cooling fan 24 is used. Since it is cooled by, it is possible to maintain the dielectric belt 8 at 40 ° C. or lower. Therefore, for example, even when the size of the transfer paper P or the number of continuously transferred sheets is different, the temperature rise, temperature instability, and temperature nonuniformity of the photoconductor drum 1 are prevented, and the charging characteristics of the photoconductor 1 are affected. In addition, a good toner image can be formed on the photoconductor 1 without the conductive magnetic toner T being dissolved on the photoconductor 1, and a stable transferred image can be always obtained.

The above embodiment is not intended to limit the present invention, and various modifications can be made within the scope of the present invention.
For example, in the above-described embodiment, the photosensitive drum 1 which is obtained by sequentially stacking the transparent conductive layer 1b and the photoconductive layer 1c on the transparent support 1a is used as the photosensitive member for developing the toner image on the surface. In particular, the shape and configuration are not limited to this, and the conductive magnetic toner T can be brought into contact with the photosensitive layer from one side and the exposure device 7 can be arranged on the opposite side.
The toner image may be transferred at a different portion, and the shape thereof may be a plate shape or a belt shape as long as the photosensitive layer is made of an organic material.

[Second Embodiment] The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as the members shown in the drawings of the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

In the electrophotographic apparatus of this embodiment, the cooling fan 24a, which is a cooling device, is provided below the heating device 10 inside the dielectric belt 8 as shown in FIG. 6, and is not shown. Although not provided, the side plate of the electrophotographic apparatus on the side where the cooling fan 24a is provided is provided with a ventilation hole for taking in outside air and exhausting it.

Therefore, in the above electrophotographic apparatus, the dielectric belt 8 is cooled by the cooling fan 24a and is provided inside the dielectric belt 8 as in the above-described embodiment, so that the cooling fan 24a is provided. The air blown from the area other than the dielectric belt 8 is, for example,
The developing tank 2 and the photoconductor 1 do not reach, and the conductive magnetic toner T is prevented from scattering and the space can be further saved. As a result, in addition to the same effects as those of the above-described embodiment, effects such as downsizing of the device can be obtained.

[Embodiment 3] The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as the members shown in the drawings of the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

In the electrophotographic apparatus of this embodiment, the tension roller 11a, which is one of the rollers for rotating the dielectric belt 8, is made of metal, and the tension roller bearing (not shown) of the tension roller 11a is used. Is formed of metal.

In the above electrophotographic apparatus, since the dielectric belt 8 is rotating in the direction indicated by the arrow Y, when the toner image is transferred onto the transfer paper P, the dielectric belt 8 heated by the heating device 10 is used. Comes into contact with the photoreceptor 8 after coming into contact with the tension roller 11a. Therefore, when the dielectric belt 8 and the tension roller 11a come into contact with each other, the heat capacity of the tension roller 11a is much larger than the heat capacity of the dielectric belt 8 and the thermal conductivity is also good. The heat is conducted to the tension roller 11a, and the tension roller bearing supporting the tension roller 11a is in contact with the side plate of the electrophotographic apparatus, so that the heat diffusion is further improved and the heat roller 1 comes into contact with the photoreceptor 1. Before, the temperature of the dielectric belt 8 can be lowered. As a result, the same effect as that of the above embodiment can be obtained without increasing the number of parts.

[0053]

As described above, in the electrophotographic apparatus according to the first aspect of the present invention, the cooling device for cooling the dielectric belt is provided near the dielectric belt.

Therefore, as the temperature of the photoconductor rises, temperature instability and temperature nonuniformity of the photoconductor are suppressed, and the charging property of the photoconductor and the toner property of the toner are stabilized, The effect is that a good transferred image can be obtained.

According to a second aspect of the present invention, in the electrophotographic apparatus according to the first aspect, the cooling device is provided inside the photoconductor belt.

Therefore, in addition to the same effect as described above, air blown from the cooling device can be prevented from reaching the portion other than the dielectric belt, and a new space for installing the cooling device can be provided. There is an effect that it is possible to achieve space saving without need, and eventually to downsize the device.

In the electrophotographic apparatus according to the third aspect of the present invention, the dielectric belt is provided with a plurality of rollers for applying tension and driving force, and is provided between the heating device downstream side and the photoconductor upstream side. Among the rollers arranged, at least one roller is made of metal.

Therefore, the roller made of metal can cool the dielectric belt, and the same effect as described above can be obtained without increasing the number of parts.

According to a fourth aspect of the present invention, in the electrophotographic apparatus according to the third aspect, the bearing for supporting the roller made of metal is made of metal.

Therefore, the bearing made of metal further improves the heat diffusivity, and a further cooling effect can be expected, and the same effect as described above can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a photosensitive drum, a developing device, an exposure device, and a dielectric belt that form an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing various components constituting the electrophotographic apparatus.

FIG. 3 is an explanatory diagram showing a state where the surface of the photosensitive drum is charged by contact with a conductive magnetic toner.

FIG. 4 is an explanatory diagram showing a state where the surface of the photosensitive drum is neutralized by exposure of an exposure device.

FIG. 5 is an explanatory diagram showing a state in which a toner image is developed on the surface of the photosensitive drum.

FIG. 6 is a schematic configuration diagram showing various components constituting an electrophotographic apparatus according to another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing various components constituting an electrophotographic apparatus according to another embodiment of the present invention.

FIG. 8 is a schematic diagram showing a configuration of an image forming apparatus adopting a Carlson process of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 8 Dielectric belt 10 Heating device 11a Tension roller (roller) 12 Pressure roller (pressing means) P Transfer paper (recording material) T Conductive magnetic toner (toner)

Claims (4)

[Claims] 1. A dielectric belt to which a toner image formed on a photoconductor is transferred, and a heating device for heating and melting the toner of the toner image formed on the dielectric belt. At the same time, the overlapping portion of the dielectric belt and the recording material is pressed toward the heating device at a position facing the heating device with the dielectric belt and the recording material fed over the dielectric belt interposed therebetween. An electrophotographic apparatus provided with a pressing means, wherein a cooling device for cooling the dielectric belt is provided in the vicinity of the dielectric belt. 2. The electrophotographic apparatus according to claim 1, wherein the cooling device is provided inside a dielectric belt. 3. A dielectric belt to which a toner image formed on a photoconductor is transferred, and a heating device for heating and melting the toner of the toner image formed on the dielectric belt. At the same time, the overlapping portion of the dielectric belt and the recording material is pressed toward the heating device at a position facing the heating device with the dielectric belt and the recording material fed over the dielectric belt interposed therebetween. An electrophotographic apparatus provided with a pressing unit, wherein the dielectric belt is provided with a plurality of rollers for applying tension and driving force to the dielectric belt, and the heating device downstream side and the photoconductor upstream side are provided. Of the rollers placed between
An electrophotographic apparatus, wherein at least one roller is made of metal. 4. The electrophotographic apparatus according to claim 3, wherein the bearing for supporting the roller made of metal is made of metal.