JPH1165290A - Wet electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently heat and melt toner transferred to an intermediate transfer body without having thermal effect on a photoreceptor in the case of using the intermediate transfer body in constitution where high-viscosity and high-concentration liquid toner exhibiting nonvolatilization is used. SOLUTION: In this wet electrophotographic device; the surface of the intermediate transfer body 15 is partially heated at a position before the body 15 is brought into contact with a pressure roller 19 by a heating device 18 heating an intermediate transfer body. The device 18 is constituted of a roller rotated while abutting on the body 15 and heated from the inside and a belt driven by a heating roller or a heat radiation means disposed in non-contact with the intermediate transfer body. The body 15 is constituted of a thin resin layer which forms an outer surface and is excellent in the releasing property of the melted toner and material positioned inside the resin layer and having high thermal insulation property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet type electrophotographic apparatus using a non-volatile, high-viscosity, high-concentration liquid toner, and more particularly, to a method using an intermediate transfer member. The present invention relates to a wet electrophotographic apparatus capable of efficiently heating and melting toner transferred to an intermediate transfer member without affecting the toner.

[0002]

2. Description of the Related Art In an electrophotographic apparatus in which an electrostatic latent image is formed on a photosensitive member (photosensitive drum), toner is adhered to the image, and the image is transferred to paper and fixed, a dry type using powder toner is widely used. Used.

However, the powder toner has a problem that the toner is scattered, and the toner particles have a particle size of 7 to 10 μm.
There is a problem that the resolution is poor due to the large value of m.
Therefore, when high resolution is required, a wet type using a liquid toner is used. This is because the liquid toner has toner particles as small as about 1 μm and the charge amount is large, so that disturbance of the toner image hardly occurs and high resolution can be realized.

In a conventional wet-type electrophotographic apparatus, a low-viscosity liquid toner in which a toner is mixed with an organic solvent at a ratio of 1 to 2% is used as a developing solution. However, such a developer uses an organic solvent that is harmful to the human body and uses a large amount of the organic solvent because of its low toner concentration, which has a serious problem of causing environmental problems.

[0005] Against this background, a wet type using a high-viscosity, high-concentration developer constituted by dispersing a high-concentration toner in silicon oil or the like is described in International Publication No. WO95 / 08792. An invention of an electrophotographic apparatus has been disclosed.

The use of this liquid toner has the advantages that the problem of harm to the human body does not occur, and the high toner concentration eliminates the need to use a large amount of developer.

On the other hand, as a method for fixing the toner adhered to the electrostatic latent image on the photoreceptor to a print medium, the toner adhered to the photoreceptor is transferred to an intermediate transfer member, and the intermediate transfer member is heated. A method in which the toner is melted and fixed on the print medium, and the toner attached to the photoreceptor is transferred to the print medium using the force of an electric field without using an intermediate transfer body, thereby printing the print medium. There is a method in which the toner is melted and fixed by heating.

The former fixing method has an advantage that the printing medium only needs to be passed once through the intermediate transfer member, and is widely used when handling color images. On the other hand, the latter fixing method has an advantage in that heat is not transmitted to the photosensitive member because no intermediate transfer member is used, and is widely used when handling monochrome images.

Even when a high-viscosity, high-concentration liquid toner exhibiting non-volatility as described above is used, conventionally, the toner is printed according to the former fixing method in accordance with the same configuration as that used in the prior art. A method of fixing to a medium or fixing toner to a print medium according to the latter fixing method is adopted.

[0010] For example, “International Publication Number WO95 / 087
92 ", according to the latter fixing method, the toner attached to the photoreceptor is transferred to a print medium using the force of an electric field, and the toner is melted and fixed by heating the print medium. The method has been adopted.

[0011]

When a color image is handled, toner applied to a photoreceptor is transferred to a print medium by utilizing the force of an electric field, and the toner is melted by heating the print medium. If the printing method is adopted, the print medium must pass through the position of the photoreceptor at least three times (four times when black is realized by one toner), which poses a practical problem.

From now on, when handling a color image, there is a method in which the toner adhered to the photoreceptor is transferred to an intermediate transfer member, and the intermediate transfer member is heated to melt the toner and fix it on a print medium. Will be taken. When adopting a configuration in which toner is fixed on a print medium according to this method, as shown in the conventional configuration of FIG. 14, an intermediate transfer roller composed of a hollow metal drum is prepared as an intermediate transfer member, and the hollow portion is provided in the hollow portion. A configuration in which a halogen heater is disposed to heat the entire intermediate transfer body has been adopted.

However, according to this configuration, there is a problem in that the heat of the intermediate transfer body having a constantly high surface temperature is transmitted to the photosensitive drum, which adversely affects the photosensitive drum. However, when using a high-viscosity, high-concentration developer composed by dispersing a high-concentration toner in silicon oil or the like, the heat capacity of the toner decreases due to the small toner particles. Different methods of heating the intermediate transfer member are feasible, which may be able to prevent the photoconductor from being affected by heat.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is directed to a configuration using a non-volatile, high-viscosity, high-concentration liquid toner. It is an object of the present invention to provide a new wet type electrophotographic apparatus capable of efficiently heating and melting the toner transferred to the intermediate transfer member without affecting the toner.

[0015]

FIG. 1 shows the overall structure of a wet electrophotographic apparatus according to the present invention. The photoconductor 10 is
After being charged to about 700 V by the charging device 11, it is exposed by the exposure device 12, and the potential of the exposed portion becomes about 1
An electrostatic latent image of 00V is formed.

The pre-wetting device 13 applies silicone oil having a viscosity of about 2.5 cSt to the surface of the photoreceptor 10 in a thickness of 4 to 5 μm. The developing device 14 has a yellow /
Provided in association with magenta / cyan / black and biased against the photoreceptor, the toner viscosity is 400 to 4
A non-volatile, high-viscosity, high-concentration liquid toner having a carrier viscosity of 20 cSt at 000 mPa · S is used as the liquid developer. The supply of the developing solution is performed by using an applicator roller while thinly extending the toner from the reservoir to convey the developing solution, whereby a toner layer having a thickness of 2 to 3 μm is formed on the developing roller.
The positively charged toner is supplied to the photoconductor 10 according to an electric field between the photoconductor 10 and toner particles adhere to the exposed portion of the photoconductor 10 charged to about 100V.

The intermediate transfer member 15 is biased at about -800 V, and the photosensitive member 1 is moved in accordance with the electric field between the intermediate member 15 and the photosensitive member 10.
The toner attached to 0 is transferred in the order of yellow, magenta, cyan, and black. The pressure roller 19 fixes the toner of the intermediate transfer body 15 melted by the heating device 18 on the print medium. And, this intermediate transfer body 15
A thin resin layer that forms an outer surface and has excellent releasability of the molten toner, and a film means that is made of a material having a high heat insulating property located inside the resin layer or forms an outer surface and serves as a toner adhesion surface; It can be composed of a heat insulating material located inside the film means.

The heating device 18 partially heats the surface of the intermediate transfer member 15 at a position before contacting the pressure roller 19. The heating device 18 is constituted by a roller which is heated from the inside which rotates while being in contact with the intermediate transfer member 15, a belt driven by a heating roller, or a heat radiating means which is disposed in non-contact with the intermediate transfer member. Can be.

The heating means is preliminarily heated so that the heating means is brought into contact with the intermediate transfer member 15 only when melt-transferring to a print medium.
Prior to the melting and heating of the toner, preheating can be performed so as not to melt and heat the toner.

Further, the heating means is provided with a control means so that the heating amount of the heating means can be controlled in accordance with information on the amount of toner adhering to the intermediate transfer member 15. Further, a cooling means for cooling the surface of the intermediate transfer body 15 at a position after contact with the pressure roller 19 can be provided.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail according to embodiments. In the present invention, a non-volatile, high-viscosity, high-concentration liquid toner is used as a liquid developer. The liquid toner is obtained by dispersing toner particles such as a pigment in a liquid carrier (oil). It is.

FIG. 1 shows the overall configuration of a wet electrophotographic apparatus provided with the present invention. As shown in FIG. 1, a wet electrophotographic apparatus according to the present invention includes a photosensitive member 10 and a charging device 11.
, An exposure device 12, a pre-wet device 13, a developing device 14, an intermediate transfer member 15, a blade 16, a charge removing device 17, a heating device 18, and a pressure roller 19.

The charging device 11 applies about 700 V
To be charged. The exposure device 12 forms an electrostatic latent image on the photoconductor 10 by exposing the photoconductor 10 using a laser beam having a wavelength of 780 nm so that the potential of the exposed portion becomes about 100 V.

The pre-wetting device 13 applies silicone oil having a viscosity of about 2.5 cSt to the surface of the photoreceptor 10 in a thickness of 4 to 5 μm. Here, the pre-wet device 1
In No. 3, the pre-wet process may be performed before the exposure process performed by the exposure device 12, or the pre-wet process may be performed after the exposure process.

The developing device 14 is provided in association with yellow / magenta / cyan / black, and is biased to about 400 V, as shown in FIG.
Forming a 2-3 μm thick toner layer on the developing roller 141 by transporting liquid toner having a carrier viscosity of 20 cSt at 4000 mPa · S while thinly extending it from the toner pool using the applicator roller 140. By supplying the positively charged toner to the photoconductor 10 in accordance with the electric field between the photoconductor 10 and the
The toner adheres to the exposed portion of the photoconductor 10 charged to 0V.

According to the pre-wet layer applied by the pre-wet device 13, as shown in FIG. 3, the toner can be prevented from adhering to the non-exposed portion of the photoreceptor 10.

The intermediate transfer member 15 is biased to about -800 V, and the photosensitive member 1
The toner attached to 0 is transferred. This intermediate transfer member 15
First, yellow toner adhered to the photoconductor 10 is transferred, then magenta toner adhered to the photoconductor 10 is transferred, and then cyan toner adhered to the photoconductor 10 is transferred. Then, the black toner attached to the photoconductor 10 is transferred.

The blade 16 removes toner and pre-wet liquid remaining on the photoreceptor 10. The neutralization device 17 neutralizes the photoconductor 10. The heating device 18 is used for the intermediate transfer member 15.
By heating the surface, the toner attached to the intermediate transfer member 15 is melted. The pressure roller 19 fixes the toner of the intermediate transfer body 15 melted by the heating device 18 on the print medium. Thus, the heating device 18 and the pressure roller 19
, The toner adhered to the intermediate transfer body 15 is melted and fixed to the print medium without heating the print medium, so that print media other than paper can be handled.

Next, the structure of the intermediate transfer member and the heating device thereof, which are features of the present invention, will be described in detail with reference to the drawings. FIG. 4 shows an example of heating such an intermediate transfer member (illustrated as a roller, but a belt described later can also be used). After each of the four color toners has been transferred from the photosensitive drum to the intermediate transfer member a total of four times, the toner transferred to the intermediate transfer member is heated and then melted once on a print medium such as paper. Transcribed. According to the present invention, when the intermediate roller is heated, only the surface of the intermediate transfer body and the toner transferred thereon are heated.

In FIG. 4, as an external heat source, a heat roller having a heat source therein is provided outside the intermediate transfer member so as to be driven and rotated by the intermediate transfer member. Due to the contact heat transfer between the heat roller and the intermediate transfer member, the surface of the intermediate transfer member and the toner transferred thereon are heated. A toner release coat layer such as a fluorine coating can be formed so that the toner does not adhere to the surface of the heat roller. In addition, the surface layers of the heat roller and the intermediate transfer member can be made of a metal material such as aluminum or copper having good thermal conductivity. This makes it possible to improve the contact heat transfer from the heat roller to the intermediate transfer member, and to sufficiently raise the surface temperature of the intermediate transfer member.

FIG. 5 shows another example of such an external heat source. In this example, the surface of the intermediate transfer member can be heated by a non-contact heating source by radiant heat transfer, for example, a halogen lamp. Further, a reflector (reflector) for reflecting radiant heat from the halogen lamp toward the intermediate transfer member is provided. With such a radiation heat transfer source, not only the surface of the intermediate transfer body but also the toner is directly heated. At this time, a radiation heat transfer source that does not make a difference between the four colors of the toner is selected. It is desirable to do. As such a radiation heat transfer source, a far-infrared halogen heater can be used.

By making the surface of the intermediate transfer member a mirror surface or a metallic glossy surface that reflects infrared rays, the infrared rays emitted from the radiation heat transfer source can be reflected, and far infrared rays can be collected in the toner image portion. The input energy of the far-infrared heater can be controlled so as to be changed according to the amount of toner transferred to the intermediate transfer member based on, for example, an output signal from an exposure laser source or image data. As a result, it is possible to prevent excessive temperature rise of the toner in the small image area, and to make the toner melting state appropriate.

Further, the surface of the intermediate transfer member may be heated rather than directly heating the toner, thereby heating the toner on the surface. As a radiant heat source therefor, a near-infrared heater is suitable, and the heating efficiency of the surface of the intermediate transfer member can be increased by making the surface of the intermediate transfer member black with high near-infrared absorptivity.

The near-infrared type radiance peak is at a wavelength of about 1 μm which is close to the visible light region (380 nm to 780 nm). The color of a color toner is generated by absorption (or transmission) in a certain wavelength region in visible light. For example, yellow absorbs short wavelength blue light and reflects green and red light. Black toner has a high absorptivity regardless of wavelength. Therefore,
If a near-infrared type is used, it is more appropriate to uniformly heat the surface of the black intermediate transfer member and then indirectly heat the toner by heat conduction, rather than directly heating the color toner.

On the other hand, the wavelength of the output peak of the far infrared ray type is 3 to 4 μm. The infrared absorption characteristic of the polymer resin, which is a main component of the toner, has a peak at about 3 μm. For infrared heating, it is more efficient to match the output peak on the heating side with the absorption peak wavelength on the heated side. Therefore, the far-infrared type can uniformly heat the toner regardless of the color (absorption characteristics).

FIG. 6 shows an example of the structure of the intermediate transfer member. Here, the intermediate transfer roller exemplified as the roller configuration has a rigid impression cylinder formed of metal such as aluminum at the center. This impression cylinder has conductivity so that a voltage can be applied from a shaft or the like to transfer the toner image on the photosensitive drum onto the intermediate transfer body by electrostatic force. Has the hardness to apply the pressure necessary for melt transfer onto the medium. A sponge foam or rubber having good thermal insulation is provided on the impression cylinder, and a thin solid film layer which receives heat is provided on the surface thereof. As this solid film material, copper with excellent thermal conductivity to toner,
A metal foil film of aluminum or the like can be used. As a result, the heat capacity is reduced as a whole, and the amount of heat supplied can be reduced, while the surface temperature can be easily increased. In addition, since the heat capacity is small, the cooling property after transferring the molten toner onto a medium such as paper is good, and unnecessary heating of the photosensitive drum is eliminated. By setting the thickness of the solid film layer as thin as possible in terms of strength, and preferably in the range of 30 to 100 μm, instantaneous heating and power saving are further improved. Further, on the surface of the solid film layer, a coat layer for releasing the molten toner, for example, a fluorine coating can be formed. FIG. 7 shows an example of a residual heat cooling unit of the intermediate transfer member. The above-described intermediate transfer body can be configured to have a small heat capacity, and therefore, the intermediate transfer body after the toner is melt-transferred to a medium such as paper has a good cooling property, but it is necessary to further improve the cooling property. Means can be provided at a position after the melt transfer. As this means, as shown, a metal roller or a pipe can be driven to rotate on the surface of the intermediate transfer member, thereby removing heat on the surface of the intermediate transfer member. This can prevent secondary heating of the photosensitive drum by the intermediate transfer member. Further, by providing fins with folds inside the cooling metal pipe and flowing a fluid such as air or water inside the pipe, the cooling effect of the intermediate transfer member can be further enhanced.

As another example of the cooling means, a liquid having good volatility such as a pre-wet liquid used for liquid development can be applied to the surface of the intermediate transfer member after the toner is melted. Alternatively, such volatile liquids can be sprayed from the metal roller when used with a cooling metal roller as described above. Thereby, the intermediate transfer member can be cooled by the heat of vaporization when the liquid evaporates.

FIG. 8 shows an example of an intermediate transfer member for preheating. Normally, as described above, the toner on the intermediate transfer body is heated after all the toners of the four colors are transferred from the photosensitive drum to the intermediate transfer body. Before the last toner of the color is transferred, for example, at the time of transferring the second or third color toner, a preliminary voltage that does not melt the toner is applied to the halogen lamp.

By setting the preliminary voltage to a fraction of the rated value, it is possible to volatilize a pre-wetting liquid and a carrier agent unnecessary for toner fusion transfer, and to reduce the rise time when the main voltage is applied to the halogen heater. It can also be shortened. Furthermore, by preheating the surface of the intermediate transfer member and the toner, power consumption during main heating can be reduced.

FIGS. 9 and 10 illustrate a configuration in which the heat roller is brought into contact with the intermediate transfer belt only during fusion transfer. 9 shows that the intermediate transfer belt is driven around three small rollers (one also serves as a transfer backup roller), while FIG. 10 is driven around four small rollers. An example is shown.

In each of the above examples, the toner of the photoreceptor is transferred to the intermediate transfer belt in four colors and then melt-transferred to a print medium such as paper at one time. It is configured to be in contact with.
9 and 10 each show a retracted state in which the heat roller is inside the belt and is not in contact with the belt. In the retracted state, the toner of each color is transferred from the photoconductor to the belt.

After the completion of the transfer, the heat roller is brought into contact with the belt, as shown in the right-hand diagrams of FIGS. 9 and 10, respectively. The heater inside the heat roller is turned on in advance so that the heat roller reaches an appropriate temperature during the melt transfer,
Heated.

The belt used as the intermediate transfer member has a high thermal conductivity, such as a metal belt.
Alternatively, a thin film such as a polyimide thin film is preferable. Further, as shown in FIG. 10, this heat roller can be provided in the medium transfer section, and can be configured to also serve as a backup roller for transfer to the medium.

With this configuration, the belt is heated only when necessary, so that unnecessary heat is not applied to the photosensitive drum, and the toner does not melt before the fusion transfer. Further, a stable temperature can be obtained from the leading end of the medium without worrying about the rise time of the temperature rise of the belt.

FIGS. 11 and 12 show a heating method using a heat belt. FIG. 11 shows when the heat belt is retracted, and FIG. 12 shows when the heat belt is in contact. In this example, the heat belt is driven by two rollers, and at least one of the rollers is formed by a heat roller using a halogen lamp or the like as a heat source. Preferably, both rollers are configured as heat rollers to increase the contact time between the belt and the heat roller to promote the recovery of the belt temperature in order to recover the temperature of the heat belt, which drops while the toner and the intermediate transfer member are being heated. It is.
Since the heating is performed by the belt having a constant length, the contact can be soft and the heating can be performed for a long time. In the illustrated example, a retreat configuration of the heat belt unit is provided. The heat belt is configured to be heated in advance, to be brought into contact with the intermediate transfer member only when performing the melt transfer, and to be in the retracted state at other times.

The heat belt can be made of a metal having good thermal conductivity as a whole or a base material.
It is possible to promptly supply heat from the heat belt to the intermediate transfer member and recover the temperature of the heat belt. further,
The surface layer of the belt may be a fluorine coat for toner release.

Since the heat belt and the toner image on the intermediate transfer member are in contact with each other, the state of mutual contact affects the image quality. Therefore, desirably, when the heat belt is brought into contact, only the so-called antinode portion located between the rollers, excluding the roller contact portion of the heat belt, makes soft contact. Such a configuration can be achieved by increasing the distance between the rollers. Further, in order to reduce the collapse and spread of the toner image caused by the contact pressure of the heat belt, an elastic layer such as silicone rubber having high heat resistance can be provided on the surface of the heat belt. Further, in order to eliminate the difference in peripheral speed between the belt and the intermediate transfer member, it is desirable that the belt be driven from the same drive source as the intermediate transfer member. Since the heat belt is heated while being in contact with the toner on the intermediate transfer member, the heat belt must be releasable so that the molten toner does not adhere to the heat belt. In other words, the wettability to the molten toner requires that the surface of the intermediate transfer member be larger than the surface of the heat belt, and that the surface of the print medium be larger than that. This can be achieved, for example, by coating the surface of the heat belt with fluorine and coating the surface of the intermediate transfer member with fluorine rubber. As a result, all the toner heated by the heat belt does not adhere to the heat belt, but remains on the intermediate transfer member, and then is entirely melt-transferred onto the print medium.

When heating the toner on the intermediate transfer member,
As a result, the intermediate transfer body itself is heated. Further, the heated toner needs to be kept in a molten state from the time the toner is separated from the heat belt to the time the paper contacts the printing medium under pressure. By forming the intermediate transfer member into a layer structure, the heat retention can be improved. For this reason, the intermediate transfer member is on a sponge foam or rubber with high heat insulation,
By providing a thin release resin layer, for example, a fluorine coat, which is excellent in the releasability of the molten toner, it is possible to improve the heat retaining property of the intermediate transfer body and the surface heat retaining property. At this time, the toner temperature is set to the set temperature of the heat belt (100 to 200 °).
In order to approach C), the heat capacity of the heat belt is made larger than the heat capacity of the surface resin layer of the intermediate transfer member.

The amount of toner on the intermediate transfer member varies depending on a place or a printed image, particularly during full-color printing. The heat capacity of the surface resin layer of the intermediate transfer member is made sufficiently larger than that of the toner layer so that the change in toner layer thickness does not affect the toner heating temperature. This can be achieved, for example, by setting the thickness of the surface resin layer of the intermediate transfer member to about 50 μm for a toner layer of 5 to 6 μm in total for four colors.

FIG. 13 shows a heating method using three rollers. After the toner on the intermediate transfer body is heated, the surface temperature of the toner and the intermediate transfer body decreases due to convection and heat transfer loss to the sponge layer inside the intermediate transfer body until the toner is transferred to the medium. It is necessary to shorten the time until transfer. For this purpose, it is desired to reduce the diameter of the belt drive roller on the fusion transfer side and arrange it closer to the pressure roller. However, the minimum values of the belt thickness and the roller diameter are determined from the repetitive compressive stress.

This problem is caused by the fact that, as shown in FIG.
By applying tension with the present roller, even if a small-diameter roller is used, the bending of the belt (internal compression and tensile stress) can be reduced. With this configuration, the time for which the heat belt faces the print medium is increased, so that the pre-heating of the print medium can be expected. Also,
As shown in the diagram on the right side of FIG. 13, when the small-diameter roller is made of a heat-resistant sponge roller (silicone rubber or the like), the sponge roller is elastically deformed by the tension of the belt, and the belt is bent for the small-diameter roller. Can be relatively reduced.

[0052]

According to the present invention, when a high-viscosity, high-concentration developer composed by dispersing a high-concentration toner in silicon oil or the like is used, the heat capacity of the toner is small because the toner particles are small. By partially heating the surface of the intermediate transfer member at the position before contacting the pressure roller, utilizing the characteristics described above, the image is transferred to the intermediate transfer member without affecting the photoconductor. It is possible to efficiently heat and melt the toner thus obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a wet electrophotographic apparatus according to the present invention.

FIG. 2 is an explanatory diagram of functions of an applicator roller and a developing roller.

FIG. 3 is an explanatory diagram of a function of a pre-wet layer applied by a pre-wet process.

FIG. 4 illustrates an example of heating of the intermediate transfer member using a heat roller.

FIG. 5 illustrates an example of heating of the intermediate transfer member using a halogen heater.

FIG. 6 illustrates an example of an intermediate transfer member configuration.

FIG. 7 illustrates an example of a residual heat cooling unit of the intermediate transfer member.

FIG. 8 shows an example of an intermediate transfer member for preheating.

FIG. 9 illustrates a configuration in which a heat roller is brought into contact with an intermediate transfer belt only during fusion transfer.

FIG. 10 illustrates another configuration in which a heat roller is brought into contact with an intermediate transfer belt only during fusion transfer.

FIG. 11 illustrates a heating method using a heat belt, and illustrates a state in which the heat belt is retracted.

FIG. 12 shows a heating method using a heat belt, and shows the state at the time of contact with the heat belt.

FIG. 13 shows a heating method using three rollers.

FIG. 14 shows a conventional intermediate transfer body in which a halogen heater is disposed in a hollow portion of a hollow metal drum to heat the entire intermediate transfer body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Photoconductor (drum) 11 Charging device 12 Exposure device 13 Prewet device 14 Developing device 15 Intermediate transfer member (roller) 16 Blade 17 Static elimination device 18 Heating device 19 Pressure roller

Continued on the front page (72) Inventor Hon Satoru 98, Unoki-nu, Unoki-cho, Kawakita-gun, Ishikawa Prefecture Inside PFU Co., Ltd. (72) Inventor Masanao Takahata 98, Unoki-nu, Unoki-cho, Kawakita-gun, Ishikawa 2 PFU Co., Ltd. (72) Inventor Genji Ichikawa Unoki-cho, Kawakita-gun, Ishikawa Prefecture 98 Uno-ki-nu 2 P-F Co., Ltd. (72) Inventor Shigeharu Okano Ichikawa Pref. 2 PFU Co., Ltd. (72) Inventor Yasukazu Takeda 98 characters of Unoki Nu, Unoki-cho, Hebei-gun, Ishikawa Prefecture 2 PFU Co., Ltd.

Claims (23)

[Claims] 1. A wet electrophotographic apparatus using a non-volatile, high-viscosity, high-concentration liquid toner as a liquid developer, comprising: an image support on which an electrostatic latent image is formed; and a surface of the image support. A pre-wet liquid applying means for applying a film of a pre-wet liquid, and a liquid toner as a liquid developer is supplied to the image support in contact with the image support, and between the image support and Developing means for adhering toner particles to the exposed portion of the image support in accordance with the generated electric field; transferring toner particles adhering to the image support in accordance with the electric field generated between the image support An intermediate transfer member to be rotated; a pressure roller that rotates while being in contact with the intermediate transfer member and conveys a print medium while pressing the intermediate transfer member; and a position before contacting the pressure roller with the intermediate roller. Partially heats the surface of the transfer body And a heating means for heating. 2. The wet electrophotographic apparatus according to claim 1, further comprising cooling means for cooling a surface of said intermediate transfer member at a position after contact with a pressure roller. . 3. The wet electrophotographic apparatus according to claim 1, wherein said heating means is constituted by a roller means which is heated from the inside which rotates while being in contact with the intermediate transfer member. Electrophotographic equipment. 4. The wet electrophotographic apparatus according to claim 1, wherein the heating unit is arranged in a non-contact manner with the intermediate transfer member, and at least one of the rollers is heated from the inside, A wet electrophotographic apparatus, comprising: a belt driven by the plurality of rollers to rotate while abutting on the intermediate transfer member. 5. The wet electrophotographic apparatus according to claim 1, wherein said heating means comprises a heat radiating means provided in a non-contact manner with the intermediate transfer member. apparatus. 6. The wet electrophotographic apparatus according to claim 1, wherein the intermediate transfer member is constituted by a belt driven by a plurality of rollers, and the partial heating of the surface of the intermediate transfer member is performed from the back surface of the belt. A wet electrophotographic apparatus characterized in that the processing is performed by a heat roller. 7. The wet electrophotographic apparatus according to claim 1, wherein the heating unit is heated in advance, and is brought into contact with the intermediate transfer body only when melt-transferring to a print medium. Characteristic wet electrophotographic apparatus. 8. The wet electrophotographic apparatus according to claim 1, wherein said heating means includes means for performing preliminary heating to a degree that does not melt and heat the toner prior to melting and heating the toner. A wet electrophotographic apparatus. 9. The wet electrophotographic apparatus according to claim 1, further comprising control means for controlling a heating amount of said heating means in accordance with information on an amount of toner adhering to the intermediate transfer member. A wet electrophotographic apparatus. 10. The wet electrophotographic apparatus according to claim 1, wherein the intermediate transfer body has a thin resin or rubber layer formed on an outer surface thereof and having excellent releasability of a molten toner. A wet electrophotographic apparatus, comprising: a material having a high heat insulating property, which is located inside a resin layer. 11. The wet electrophotographic apparatus according to claim 1, wherein the intermediate transfer member has an outer surface formed thereon as a toner adhering surface, and is located inside the film device. do it,
And a heat insulating layer means made of a heat insulating material. 12. The wet electrophotographic apparatus according to claim 2, wherein said cooling means is constituted by a roller provided in non-contact with the intermediate transfer member. 13. The wet electrophotographic apparatus according to claim 2, wherein said cooling means comprises an application means for applying a volatile liquid to the intermediate transfer member. 14. The wet electrophotographic apparatus according to claim 4, wherein at least a base of said belt is made of metal. 15. The wet electrophotographic apparatus according to claim 4, wherein the belt has an elastic layer having high heat resistance on a surface thereof. 16. The wet electrophotographic apparatus according to claim 4, wherein the belt is driven from the same drive source as the intermediate transfer member so as to eliminate a difference in peripheral speed between the two. A wet electrophotographic apparatus. 17. The wet electrophotographic apparatus according to claim 4, wherein the belt is driven by three rollers, and is provided close to a pressure roller and close to the surface of the intermediate transfer member. A wet electrophotographic apparatus, wherein one roller has a smaller diameter than other rollers. 18. The wet electrophotographic apparatus according to claim 5, wherein the heat radiating means is constituted by far-infrared heater means, and the intermediate transfer body is constituted by a surface whose surface reflects infrared rays. Characteristic wet electrophotographic apparatus. 19. The wet electrophotographic apparatus according to claim 5, wherein the heat radiating means is constituted by near-infrared heater means, and the intermediate transfer member is constituted by a surface having a surface absorbing infrared rays. Characteristic wet electrophotographic apparatus. 20. The wet electrophotographic apparatus according to claim 6, wherein said belt is made of a material having high thermal conductivity. 21. The wet-type electrophotographic apparatus according to claim 6, wherein the heat roller is provided in a transfer section of the medium and also serves as a backup roller for transfer to the medium. 22. The wet electrophotographic apparatus according to claim 11, wherein said film means is made of a metal thin film. 23. The wet electrophotographic apparatus according to claim 22, wherein said film means has a thickness of 30 to 100 μm.