JP2000214688A - Wet image forming device - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a wet image forming apparatus capable of reliably obtaining a desired aggregation effect of visualized particles in a liquid developer layer. SOLUTION: A liquid developer containing a high concentration of toner particles is applied on a developing belt 12 to form a liquid developer layer, and an electrostatic latent image formed on a photoreceptor 1 by the liquid developer layer is formed. A corona charger 14 for aggregating the toner particles by an electric action in a wet image forming apparatus for developing an image.
And a controller 20 for controlling the intensity of the current flowing from the corona charger toward the developing belt. At this time, the control device controls the magnitude of the current based on the temperature condition detected by the temperature sensor 21 so that the aggregation effect can be maximized under the temperature condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.
A liquid developer containing a high concentration of visualized particles is applied on a developer carrier to form a liquid developer layer, and the visualized particles in the liquid developer layer are electrically charged by a particle aggregating means. The present invention relates to a wet image forming apparatus for aggregating by electrostatic action and developing an electrostatic latent image formed on a latent image carrier by electrophotography, electrostatic recording, ion flow, or the like.

[0002]

2. Description of the Related Art Conventionally, as a wet image forming apparatus of this type, for example, between a developer carrying member and a developer thin layer member,
An image forming apparatus for forming an electric field such that toner particles in a liquid developer supplied to a gap between the developer carrying member and the developer thin layer member electrophoreses toward the surface of the developer carrying member is disclosed in -339990. In this image forming apparatus, an electric field is formed in the gap between the developer carrying member and the developer thin layer member to electrically balance the toner particles in the liquid developer layer in the liquid developer. Electrophoresis until reaching. As a result, the liquid developer layer has a high concentration in the vicinity of the surface of the developer carrying member. Then, the portion of the liquid developer layer having a low concentration is removed by flowing out from the lowermost portion of the developer thin layer member, for example, under the flow of its own weight. As a result, a high-density and uniform liquid developer thin layer is formed on the developer carrier, and a high-quality image without image density unevenness can be formed on a recording medium.

Japanese Patent Application Laid-Open No. 10-312113 discloses a developer pressing means for pressing a high-concentration liquid developer thinly applied on a developer carrier to smooth the surface of a visualized particle layer. A wet image forming apparatus having the same is disclosed. In the wet image forming apparatus disclosed in this publication, before the liquid developer layer formed on the developer carrying member reaches the pressure contact area of the developer pressure contact means, the liquid developer layer is charged by a charge applying means such as a corona charger. Then, electric charges are injected into the liquid developer layer. Thus, the toner particles in the liquid developer layer and the toner particles are aggregated by exerting a strong aggregating force between the toner particles and the developer carrier. By aggregating the toner particles in this manner, the liquid developer layer has a toner layer having a high toner concentration and a toner layer having a high toner concentration located near the surface of the developer carrier, and has a very low toner concentration. Separate from the solvent layer. The toner layer is pressed with a constant force by the developer pressure roller when passing through the position of the developer pressure roller as the developer pressure means, and the surface of the toner layer is smoothed. Is done. As a result, a liquid developer layer in which toner particles are uniformly dispersed without density unevenness is formed on the developer carrying member, and an image without image density unevenness can be formed on a recording medium.

Japanese Patent Application Laid-Open No. Hei 10-293469 discloses a method in which a liquid developer layer containing visualized particles is formed on a developer carrier, and a static developer on the image carrier coated with a pre-wet liquid is formed. There is disclosed an image forming apparatus for aggregating liquid developer remaining on the developer carrier after developing an electrostatic latent image and visualized particles in a pre-wet liquid attached to the developer.
In this image forming apparatus, after development, the visualized particles are aggregated near the surface of the developer carrier by a particle aggregating unit and separated into a toner aggregated layer and a liquid layer. Can be recovered.

[0005]

In the above-mentioned conventional image forming apparatus, in order to agglomerate the toner particles, the toner particles dispersed in the liquid developer layer by applying an electric action to the toner particles. Need to be aggregated. For example, in JP-A-10-339990, an electric field is formed by an electrode plate or the like.
In Japanese Patent No. 2113 and Japanese Patent Application Laid-Open No. 10-293469, charge is injected by a corona charger or the like to aggregate the toner particles. However, when the toner particles are agglomerated by the electric action, the electric action acting on the toner particles depends on the viscosity of the liquid developer containing the toner particles, the electric properties of the toner particles, and the like. It has been found that the temperature varies depending on the properties of the developer or the environmental conditions in which the liquid developer is used.

[0006] This point will be specifically described with reference to the results of an experiment conducted on the change in image density of an image formed on a recording medium when the environmental condition of the liquid developer is changed.
In this experiment, using an image forming apparatus described in an embodiment described later, charge injection was performed by a corona charger as charge applying means toward a liquid developer thin layer formed on a developing belt as a developer carrier. Then, the temperature condition was changed as an environmental condition at that time, and a change in image density with respect to a current (hereinafter, referred to as an effective current) flowing from the corona charger toward the developing belt was measured.

FIG. 2 is a graph showing the measurement results of the image density with respect to the effective current of the corona charger under the environmental conditions of a temperature of 10 ° C. and a humidity of 35%. Under these environmental conditions, the effective current supplied from the corona charger is zero.
At μA, that is, when the corona charger was not placed or operated, the image density was highest. As shown in FIG. 2, the image density tends to decrease as the effective current increases.

FIG. 3 is a graph showing the measurement results of the image density with respect to the effective current of the corona charger under the environmental conditions of a temperature of 25 ° C. and a humidity of 35%. Under these environmental conditions, the image density increases until the effective current supplied from the corona charger reaches about 7 μA, and when the effective current exceeds about 7 μA, there is a tendency for the image density to remain largely unchanged. Under this environmental condition, the effective current is about 7 μm.
In the case of A, the image density was the highest.

FIG. 4 is a graph showing the measurement results of the image density with respect to the effective current of the corona charger under the environmental conditions of a temperature of 45 ° C. and a humidity of 35%. Under these environmental conditions, the image density increases until the effective current supplied from the corona charger reaches about 15 μA, and when the effective current exceeds about 15 μA, the image density tends to be largely unchanged. Under these environmental conditions, the image density was highest when the effective current was about 15 μA.

As described above, when the liquid developer is used under different temperature conditions, the optimum effective current value for maximizing the image density differs depending on the temperature conditions. Therefore, in order to obtain a good image having a high image density using a high-concentration liquid developer, various characteristics such as electrical characteristics and physical characteristics of the liquid developer or toner particles, temperature and humidity, etc. In accordance with environmental conditions and the like, it is necessary to change the electrical action such as the effective current flowing from the corona charger, which acts to aggregate the toner particles.

The present invention has been made in view of the above background, and an object of the present invention is to provide a wet image forming method capable of reliably obtaining a desired aggregation effect of visualized particles in a liquid developer layer. It is to provide a device.

[0012]

In order to achieve the above object, according to the present invention, a liquid developer containing a high concentration of visualized particles is coated on a developer carrier. In a wet image forming apparatus which forms a liquid developer layer and develops an electrostatic latent image formed on a latent image carrier by the liquid developer layer, a particle aggregation in which the visualized particles are aggregated by an electric action. Means and control means for controlling the intensity of the electric action by the particle aggregating means.

In this wet image forming apparatus, when the visualized particles in the liquid developer layer formed on the developer carrier are aggregated by the electric action of the particle aggregation means such as an electrode plate and a corona charger. The intensity of the electrical action can be controlled by the control means. As a result, the visualized particles are aggregated in accordance with various characteristics such as electrical and physical characteristics of the liquid developer or the visualized particles used in the wet image forming apparatus, and environmental conditions such as temperature and humidity. It is possible to adjust the intensity of the electric action for performing the operation. As a result, for example, in an image forming apparatus that performs development using a plurality of types of liquid developers, when conditions such as electrical characteristics and physical characteristics of various liquid developers or visualized particles contained therein are different. Even in such a case, the above-described control means can cause each of the visualized particles to be aggregated in a state where the aggregation effect is highest when developing each liquid developer.

In particular, a second aspect of the present invention is the wet image forming apparatus according to the first aspect, wherein the control means controls the intensity of the electric action according to an environmental condition. . In this wet image forming apparatus, the intensity of the electric action for aggregating the visualized particles can be adjusted according to environmental conditions such as temperature and humidity, and an optimal agglutination effect can be exhibited. For example, in an image forming apparatus that performs development using one or more types of liquid developers, even if the environmental conditions and the like are different, the above-described control unit causes the most agglutination of the liquid developers during development. The intensity of the electric action having a high effect can be selected to aggregate the visualized particles. In particular, even among these environmental conditions, the temperature condition has a great effect on the coagulation effect. Therefore, if the optimal electric action strength is selected according to the temperature condition, the effect can be further enhanced.

According to a fourth aspect of the present invention, in the wet-type image forming apparatus of the first, second or third aspect, the control means controls the intensity of the electric action according to a solid content of the liquid developer. It is characterized by controlling. In this wet image forming apparatus, the intensity of the electric action for aggregating the visualized particles is adjusted in accordance with the solid content of the liquid developer containing the visualized particles, so that the optimal aggregating effect is obtained. Can be demonstrated. Thus, for example, in an image forming apparatus that performs development using a plurality of types of liquid developers, the solid content ratios of various liquid developers are different, and the visualized particles contained in these liquid developers are aggregated. Even when the strength of the electric action most suitable for the liquid developer is different, the above-mentioned control means can cause each of the visualized particles to be aggregated in a state where each of the liquid developers has the highest aggregation effect at the time of development.

Further, the invention of claim 5 is the invention according to claims 1, 2,
In the wet-type image forming apparatus of 3 or 4, the control means controls the intensity of the electric action according to the electric characteristics of the visualized particles. In order to aggregate the visualized particles in the liquid developer, the visualized particles must be given an electrical action by the above-mentioned particle aggregating means. At this time, for example, in an image forming apparatus that performs development using a plurality of types of liquid developers, when the electric action of the visualized particles contained in various liquid developers is different,
Even if the same electrical action is applied, the aggregation effect differs for each liquid developer. Therefore, in the wet image forming apparatus according to the present invention, by adjusting the intensity of the electric action for aggregating the visualized particles in accordance with the electrical characteristics of the visualized particles, each liquid developer During the development, each of the visualized particles can be aggregated in a state where the aggregation effect is the highest.

The invention according to claim 6 is based on claims 1, 2,
In the wet image forming apparatus of 3, 4, or 5, the particle aggregating means is a non-contact type charge applying means. Here, the non-contact type charge applying means means that an electric action is given to the visualized particles in the liquid developer layer without contacting the liquid developer layer formed on the developer carrier. Means that can be used, for example, a non-contact type charger such as a corona charger can be used.

In the wet image forming apparatus according to the present invention,
Particle aggregating means for aggregating the visualized particles in the liquid developer layer formed on the developer carrying member, without contacting the liquid developer layer, gives an electrical action to the visualized particles. be able to. Therefore, for example, when the visualized particles in the liquid developer layer before development are aggregated, the surface of the liquid developer layer is not disturbed. This makes it possible to uniformly transfer the visualized particles to the electrostatic latent image on the latent image carrier, thereby suppressing unevenness in image density.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter referred to as a copying machine) as an image forming apparatus will be described. The copying machine according to the present embodiment is a single-color (monochrome) copying machine having a solid content of 1%.
The liquid developer having the above-mentioned high concentration and high viscosity of 100 to 10000 mPa · s is used. The toner, which is the visualized particles of the liquid developer, is charged to the positive electrode.

First, the configuration and operation of the entire copying machine according to this embodiment will be described. FIG. 1 is a front view illustrating a schematic configuration of a copying machine according to the present embodiment. This copier is
Around a photoreceptor 1 as a latent image carrier, a charging roller 2 as a charging unit, an exposure device 3 as a writing unit, a liquid developing device 10 as a developing unit, and a transfer device 4 as a transfer unit And a charge removing lamp 5 as a charge removing means and a cleaning blade 6 as a cleaning means. A transfer sheet 7 as a recording medium to which a toner image is transferred by the transfer device 4 passes through a transfer device from a paper supply unit (not shown) through a paper feed path, and a fixing device (not shown) as a fixing unit. Transported to

After the photosensitive member 1 is positively charged by the charging roller 2, the exposure device 3 irradiates light corresponding to an image to form an electrostatic latent image. This electrostatic latent image is developed by the liquid developing device 10 with a liquid developer and visualized. The toner image formed on the photoreceptor 1 by the liquid developer is transferred to the transfer paper 7 conveyed from the paper supply unit via the transfer device 4. Then, the toner transferred to the transfer paper 7 is sent to the fixing device, and is fixed to the transfer paper under the action of heat and pressure. The residual transfer developer remaining on the photoconductor 1 is removed by the cleaning blade 6 after the residual potential on the photoconductor is erased by the neutralization lamp 5, and the image forming process is completed. Thereafter, the above-described processing is repeated.

Next, the structure and operation of the liquid developing device 10 of the copying machine will be described. The liquid developing device 10 according to the present embodiment includes a developing belt 12 as a developer carrier.
A coating device 13 for applying a liquid developer to the developing belt; and a particle aggregating device for aggregating the toner in the liquid developer layer formed on the developing belt on the surface of the developing belt. It comprises a corona charger 14 as a certain charge applying means, and a belt cleaning blade 15 for cleaning the surface of the developing belt that has passed through a developing region where the developing belt and the photoreceptor 1 face each other.

The developing belt 12 is stretched around a driving roller 11a for rotating the developing belt and a plurality of supporting rollers (11b, 11c, 11d, 11e, 11f). The rotation speed of the developing belt 12 is set to be equal to the surface moving speed of the photoconductor 1. When the rotation speed of the developing belt 12 is increased to speed up the image forming process, at least two of the rollers that stretch the developing belt are stretched in order to stably form a normal image. Preferably, at least one is configured as a drive roller.

The coating device 13 includes a developer storage tank 16 serving as a developer storage unit for storing the liquid developer.
, A drawing roller 17, a regulating roller 18 as a thinning means, and an application roller 19 as a developer application member. The liquid developer stored in the developer accommodating tank 16 is pumped up with the rotation of the pumping roller 17, is thinned by being regulated by the regulation roller 18, and is supplied to the application roller 19. You. Then, the liquid developer supplied to the applying roller 19 is applied to the surface of the developing belt 12, and a thin liquid developer layer is formed on the developing belt.

The corona charger 14 is disposed so as to face the surface of the developing belt between the developing area and the applying area where the applying roller 19 of the applying device 13 faces the developing belt 12. . The corona charger 14 injects a positive charge toward the liquid developer thin layer formed by the coating device 13. By this electric action, a strong cohesive force can be exerted between the toner particles in the thin liquid developer layer and between the toner particles and the developing belt 12. As a result, the liquid developer thin layer includes a toner-aggregated layer having a very high toner concentration and a solvent layer having a very low toner concentration located near the surface of the developing belt 12 while the toner particles aggregate. And separated into

The liquid developer thin layer in a state where the toner particles are aggregated is conveyed to a developing area where the thin layer of the liquid developer comes into contact with the photosensitive member 1 as the developing belt 12 rotates. In this developing area, the surface of the developing belt 12 is heated by a developing power source as a developing bias applying unit (not shown).
The potential is set to a predetermined potential having a value between the maximum value and the minimum value of the potential existing on the photoconductor 1. As a result, the toner particles in the liquid developer thin layer on the developing belt 12 are transferred to a portion having a higher potential than the surface potential of the developing belt 12 and are not transferred to a lower portion on the developing belt. Will remain. That is, the toner particles are transferred to the electrostatic latent image on the photoreceptor 1, and a toner image is formed on the photoreceptor that has passed the development area.

The toner image thus formed on the photoreceptor 1 is transferred to the transfer paper 7 through a transfer step by the transfer device 4. Then, an image is formed by fixing the toner image on the transfer paper 7 by the fixing device. In the liquid developing device 10, the liquid developer remaining on the developing belt 12 passing through the developing area is removed by a belt cleaning blade 15 arranged at a position facing the driving roller 11a.

Next, the configuration and operation of the control device 20 as control means, which is a feature of the present invention, will be described. The control device 20 controls the strength of the electric action that the corona charger 14 of the liquid developing device 10 exerts on the toner particles in the liquid developer thin layer, that is, the effective current flowing from the corona charger toward the developing belt 12. Is controlled. It is desirable that the effective current value is set to an optimum value so that the image density of the image formed on the transfer paper 7 is the highest. However, the viscosity of the liquid developer and the electric The optimum value changes depending on various conditions such as characteristics.

Therefore, in this embodiment, the control device 20 controls the effective current value in accordance with a change in the temperature condition of the liquid developer thin layer formed on the developing belt 12. ing. This control device 20
Is a temperature sensor 2 serving as a temperature detecting means which is an environmental condition detecting means provided in the vicinity of the surface of the developing belt 12.
1 connected. The temperature sensor 21 detects a temperature near the liquid developer thin layer formed on the developing belt 12 and sends the temperature data to the control device 20. The control device 20 that has received the temperature data controls the coagulation power supply 22 connected to the corona charger 14 so that the effective current value indicates an optimum value for a preset predetermined temperature.

In the present embodiment, in order to obtain the above-mentioned optimum value of the effective current value, the experiment described in the above-mentioned prior art was performed, and the optimum effective current value for a predetermined temperature was measured. Specifically, using a liquid developer having a solid content of 15%, the above temperature conditions were adjusted to 10 ° C., 25 ° C., and 45 ° C.
The image density when changing in steps was measured. And
The control device 20 controls the power supply 22 for aggregation of the corona charger 14 based on the measurement result.

FIG. 2 shows that the temperature condition in the above experiment was 10
It is a graph which shows the measurement result at the time of setting to ° C. In FIG. 2, the image density is highest when the effective current value is 0 μA, that is, when no charge is injected by the corona charger. On the other hand, when the temperature condition is 25
In FIG. 3 showing the measurement results when the temperature was set to ° C., the optimum value of the effective current was about 7 μA. In FIG. 4 showing the measurement results when the temperature condition was set to 45 ° C., the optimum value of the effective current was about 15 μA.

The viscosity of a high-viscosity liquid such as the liquid developer used in the present embodiment generally decreases as the temperature increases, and increases as the temperature decreases. Therefore, the viscosity of the liquid developer under the above three temperature conditions was also measured. As a result, the viscosity was 700 mPa · s when the temperature was 10 ° C., 1000 mPa · s when the temperature was 25 ° C., and 1250 mPa · s when the temperature was 45 ° C.

FIG. 5 is a graph showing an optimum effective current value with respect to the viscosity of the liquid developer based on the results of the above two experiments. As shown in FIG. 5, the optimum effective current value tends to increase linearly as the viscosity of the liquid developer decreases. As a result, based on the change of the optimum value shown in FIG. 5, the optimum effective current value for the temperature condition can be calculated from the relationship between the viscosity of the liquid developer (not shown) and the temperature condition. Thereby, in the control device 20 according to the present embodiment, the coagulation power supply 22 can be controlled so that the optimal effective current flows from the corona charger 14, and an image having a high image density is formed on the transfer paper 7. Can be formed.

Next, the control device 20 in the above embodiment will be described.
A first modified example will be described. The control device according to the present modification does not change the effective current value with respect to the temperature condition as in the control device 20 according to the above-described embodiment, but controls the effective current value according to the viscosity of the liquid developer used. It is. This modification is suitable for application to, for example, a full-color copying machine using two or more types of liquid developers, instead of a monochrome copying machine using one type of liquid developer as in the above-described embodiment.

The present modification will be described by taking as an example a case where the present invention is applied to a full-color copying machine using four kinds of liquid developers having different viscosities. In the present modified example, the viscosity of the liquid developer of each color to be used is measured in advance under environmental conditions under the use condition. Then, based on the viscosity data of each color, the control device controls the corona charger 14 according to the type of liquid developer formed on the developing belt 12.
Of the coagulation power supply 22 is controlled. The optimum effective current value for the viscosity data can be directly derived from the graph shown in FIG. Thereby, in the control device according to the present modification, it becomes possible to control the aggregation power supply 22 so that the optimal effective current flows from the corona charger 14 according to the type of the liquid developer.
An image having a high image density can be formed on the transfer paper 7.

Next, the control device 20 in the above embodiment will be described.
A second modified example will be described. The control device according to the present modification is different from the above-described embodiment and the first modification in that the effective current value of the corona charger 14 is controlled by the solid content of the liquid developer to be used. Note that this modification is also applied to, for example, a full-color copying machine using two or more types of liquid developers, as in the first modification.

A description will be given of an example in which the control device is applied to a full-color copying machine using four types of liquid developers having different solid contents in this modification. In this modification,
The solid content of each liquid developer to be used is measured in advance under environmental conditions under the conditions of use. The controller controls the aggregation power supply 22 of the corona charger 14 in accordance with the type of liquid developer formed on the developing belt 12 based on the solid content data of each liquid developer. .

In this modification, in order to obtain the above-mentioned optimum value of the effective current value, the optimum effective current value for a predetermined solid content was measured under environmental conditions under use conditions. Specifically, the effective current value at which the image density was maximum was measured for the liquid developers having solid contents of 5%, 10%, and 15%.

FIG. 6 is a graph showing the optimum effective current value with respect to the solid content of each liquid developer described above. The control device according to the present modified example controls the aggregation power supply according to the type of the liquid developer formed on the developing belt 12 so that the optimum effective current flows from the corona charger 14 based on the measurement result. 22 is controlled. Thereby, an image having a high image density can be formed on the transfer paper 7.

As described above, in the above-described embodiment, the corona charger, which is a non-contact type charge applying means, is used as the particle aggregating means.
Other charge applying means can be applied. Also,
As the particle aggregating means, an electric field forming means such as an electrode plate for forming an electric field capable of aggregating the visualized particles with the surface of the developer carrier can be applied instead of the charge applying means. .

Further, in the above-described embodiment, the aspect in which the particle for aggregating is provided between the coating area and the developing area to aggregate the visualized particles in order to increase the image density has been described. Is applicable as long as it agglutinates the visualized particles in the liquid developer. Therefore, for example, in order to collect and reuse the visualized particles or the solvent in the liquid developer, the developed particles in the liquid developer remaining on the developer carrier after the development are collected by the developer carrier. Aggregated near the body surface, the liquid developer is separated into a visualized particle layer and a solvent layer,
In an image forming apparatus that separately collects the visualized particles and the solvent, by increasing the aggregation effect according to the present invention,
The visualized particles and the solvent can be more reliably separated and collected.

[0042]

According to the first to sixth aspects of the present invention, the effect of coagulating the visualized particles in the liquid developer layer can be enhanced. Thereby, an excellent effect that it is possible to provide a wet image forming apparatus capable of obtaining a high quality image having a high image density by enhancing the aggregating effect of the visualized particles in the liquid developer layer before development. There is. Further, by enhancing the effect of aggregating the visualized particles in the liquid developer layer after the development, there is also an excellent effect that the visualized particles and the solvent can be reliably separated and collected.

In particular, according to the second and third aspects of the invention, there is an excellent effect that an image having a stable image density can be formed even when environmental conditions change.

According to the present invention, an image having a stable image density can be formed even when development is performed using two or more types of liquid developers having different solid contents. Has an effect.

According to the fifth aspect of the present invention, an image having a stable image density can be formed even when development is performed using two or more types of visualized particles having different electrical characteristics. Has an excellent effect.

According to the sixth aspect of the invention, the visualized particles can be uniformly transferred to the electrostatic latent image on the latent image carrier,
There is an excellent effect that an image without unevenness in image density can be formed.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of an electrophotographic copying machine according to an embodiment.

FIG. 2 is a graph showing a change in image density with respect to an effective current of a corona charger under an environmental condition at a temperature of 10 ° C.

FIG. 3 is a graph showing a change in image density with respect to an effective current of a corona charger under an environmental condition of a temperature of 25 ° C.

FIG. 4 is a graph showing a change in image density with respect to an effective current of a corona charger under an environmental condition of a temperature of 45 ° C.

FIG. 5 is a graph showing a change in the optimum effective current value of the corona charger with respect to the viscosity of the liquid developer.

FIG. 6 is a graph showing a change in an optimum effective current value of a corona charger with respect to a solid content of a liquid developer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Exposure device 4 Transfer device 5 Static elimination lamp 6 Cleaning blade 7 Transfer paper 10 Liquid developing device 12 Developing belt 13 Coating device 14 Corona charger 20 Control device 21 Temperature sensor 22 Aggregation power supply

Claims (6)

[Claims] A liquid developer containing a high concentration of visualized particles is coated on a developer carrier to form a liquid developer layer,
In a wet image forming apparatus for developing an electrostatic latent image formed on a latent image carrier by the liquid developer layer, a particle aggregating means for aggregating the visualized particles by electrical action,
And a control means for controlling the intensity of the electric action by the particle aggregating means. 2. A wet image forming apparatus according to claim 1, wherein said control means controls the intensity of said electric action according to environmental conditions. 3. A wet image forming apparatus according to claim 2, wherein said environmental condition is a temperature condition. 4. A wet image forming apparatus according to claim 1, wherein said control means controls the intensity of said electric action in accordance with a solid content of said liquid developer. Wet image forming apparatus. 5. A wet image forming apparatus according to claim 1, wherein said control means controls the intensity of said electric action according to the electric characteristics of said visualized particles. Characteristic wet image forming apparatus. 6. A wet image forming apparatus according to claim 1, wherein said particle aggregating means is a non-contact type charge applying means.