JPH08123207A - Wet image forming device - Google Patents

Abstract

PURPOSE: To prevent toner from being flocculated at a scraper part by providing a peeling electrode on which potential in a direction where toner on a rotating body is attracted is impressed near the scraper proximately to a developing roller electrode or the rotating body such as a reversely rotating squeeze roller and at a position on an upstream side in the rotating direction of the rotating body. CONSTITUTION: The peeling electrode 91 on which the voltage high enough for the toner 45a to float from the surface of the reversely rotating squeeze roller 51 is impressed by a power source for peeling bias 93 is attached near the scraper 9 proximately to the roller 51 and on the upstream side in the rotating direction of the roller 51. The toner 45a adhering to the surface of the roller 51 is peeled from the surface of the roller 51 and attracted to the electrode 91 side by electric field formed between the electrode 91 and the roller 51, so that the toner is prevented from being flocculated and accumulated at the scraper part. A plate-like or linear electrode or an electrode having proper shape is used as the peeling electrode 91 in accordance with the fitting position, the space of a fitting part, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating image carrier on which an electrostatic latent image is formed, and a developing device for supplying a liquid developer containing toner to the electrostatic latent image for development. The developing device is disposed in the vicinity of the image carrier, and includes a rotating body that is in contact with the liquid developer and is applied with an electric potential in a direction to attract the toner, and the liquid developer attached to the rotating body. The present invention relates to a wet image forming apparatus provided with a scraper for removing, and particularly to a wet image forming apparatus suitable for being adopted in an electrophotographic copying machine.

[0002]

2. Description of the Related Art Conventionally, as one of image forming apparatuses used in electrophotographic copying machines, a liquid developer in which toner is dispersed in a dispersion liquid on an image carrier on which an electrostatic latent image is formed. There is known a wet developing method in which a developing roller electrode is supplied to perform development. By the way, in the wet development method, the developing roller electrode plays an important role in preventing fringe development by forming a uniform developing electric field and obtaining a good developed image. In order to keep the parts clean, it is generally set between the image potential and the background potential. As a result, the toner that has not been used for development adheres to the developing roller electrode, particularly in the background portion, and adversely affects the subsequent developed image.

Therefore, in order to solve the problem due to the adhesion of the toner to the developing roller electrode, for example, Japanese Patent Publication No.
As described in JP-A-2-8100, a scraper is provided for the developing roller electrode, and the liquid developer on the developing roller electrode is scraped off after the developing position by this scraper, so that the toner is not always adhered to the developing roller. It has been proposed that development can be performed with a developing roller electrode.

In the wet image forming apparatus as described above, the excess dispersion liquid from the developer on the image carrier which has been developed is removed in order to prevent image deletion in the subsequent transfer step, and the background portion is removed. It is known that a reverse squeeze roller is provided in order to remove the unnecessary toner. This reverse squeeze roller rotates in the opposite direction while maintaining a small gap with the image carrier, and generates a tearing force in the liquid film on the image carrier to scrape off the excess dispersion liquid. Is configured to apply a bias potential having the same polarity as the developing bias to remove unnecessary toner in the background portion. Even in such a reverse squeeze roller, there is a reverse squeeze roller provided with a scraper for scraping off the excessive dispersion liquid adhering to the roller to feed the image carrier, and a roughly dried roller surface to the facing portion (for example, Japanese Patent Publication No. 54-345
No. 41).

[0005]

However, in the case where the developing roller electrode is provided with the scraper as described above, when the toner adhering to the developing roller electrode is scraped off, the toner is apt to aggregate in the scraper portion, and After the stop, the agglomerated toner sticks to dryness and becomes a motor load at the time of starting, or the agglomerated toner drops off and mixes into the developing tank, which adversely affects the image and deteriorates the dispersion state of the liquid developer. There is a problem that the agent cannot be reused as it is.

Also, in the reverse squeeze roller having the scraper, there is a problem that toner agglomerates in the scraper portion or drops off like the developing roller electrode having the scraper. In view of the above circumstances, the present invention provides a wet image forming apparatus including a rotating body that contacts the liquid developer, such as the developing roller electrode or the reverse squeeze roller, and a scraper for scraping the liquid developer attached to the rotating body. In the above, it is an object of the present invention to provide a wet image forming apparatus capable of preventing the generation of aggregated toner in the scraper section.

[0007]

In order to achieve the above object, a wet image forming apparatus of the present invention contains a rotating image carrier on which an electrostatic latent image is formed and a toner contained in the electrostatic latent image. A developing device for supplying the liquid developer to perform development, the developing device being disposed in the vicinity of the image carrier, and having a bias potential applied thereto, the rotating body being in contact with the liquid developer. ,
In a wet image forming apparatus comprising a scraper for removing the liquid developer attached to the rotating body, in the vicinity of the rotating body, in the vicinity of the scraper and on the upstream side in the rotation direction of the rotating body, It is characterized in that a peeling electrode to which a potential in the direction of attracting the toner on the rotating body is applied is provided.

When a plurality of rotating bodies are provided in the developing device, the peeling electrodes may be provided separately for each rotating body. When a plurality of rotating bodies are provided in the developing device, the peeling electrodes for the plurality of rotating bodies may be shared by one peeling electrode. As a specific example of the rotating body, a developing roller electrode to which a developing bias potential is applied in order to attach toner to the electrostatic latent image on the image carrier to perform development, or after development of the electrostatic latent image is performed. For removing the excess liquid developer on the image carrier from the image carrier before the transfer of the visible image on the recording medium,
An example is a reverse squeeze roller electrode which is arranged close to the image carrier and to which a bias potential is applied.

The developing device may be provided with only the developing roller electrode as the rotating body, or may be provided with only the reverse squeeze roller electrode, or the developing roller electrode. It may have both a reverse squeeze roller electrode.

[0010]

The wet image forming apparatus according to the present invention is provided with a rotating body such as a developing roller electrode having a scraper or a reverse squeeze roller, which is close to the rotating body.
Since the peeling electrode is provided near the scraper and on the upstream side in the rotation direction of the rotating body, the peeling electrode to which a potential in the direction of attracting the toner on the rotating body is applied is formed. The toner on the rotating body is attracted to the peeling electrode side by the generated electric field, so that there is no toner near the surface of the rotating body in the scraper portion, and the liquid developer on the rotating body is easily scraped off by the scraper. It is possible to prevent the toner from aggregating and sticking in the scraper portion.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing an embodiment of a wet image forming apparatus according to the present invention. The illustrated wet image forming apparatus includes an image carrier 1 made of a drum-shaped photoconductor (a drum is coated with the photoconductor), and the image carrier 1 is driven at a constant speed by a driving device (not shown). It is driven to rotate in the direction of the arrow, and a charging unit 2, an exposing unit 3, a developing unit 4, an excess liquid removing unit 5, a transfer unit 6, a cleaning unit 7, and a charge removing unit 8 are arranged around the drive unit. The developing means 4 and the excess liquid removing means 5 constitute the developing device in the present invention.

The image carrier 1 is uniformly charged by the charging means 2 and the charging power source 21 and then exposed by the laser beam 31 carrying the image information to be copied by the exposing means 3 to form an electrostatic latent image. An image is formed, the electrostatic latent image is developed with the liquid developer 45 by the developing unit 4, and the excess liquid developer 45 is removed by the excess liquid removing unit 5, and then the transfer unit 6 is formed.
And the transfer power source 62 transfers the transferred toner onto the transfer target medium 61, the cleaning unit 7 removes the residual toner and the dispersion liquid, and then the charge removing unit 8 electrically restores the initial state. To prepare for the next copying operation.

The image bearing member 1 may be composed of a rotating belt-shaped photosensitive member instead of the rotating drum-shaped photosensitive member, or instead of the exposing means 3, a multi-needle electrode head or an ion current writing means. It is also possible to use a rotating drum-shaped or belt-shaped dielectric. In either case, an electrostatic latent image is formed along the moving direction of the surroundings. As the transfer means 6, a bias roller may be used in addition to the corotron transfer means, and a method of obtaining a copy by fixing after transfer onto a transfer target medium 61 such as transfer paper, or once transferring to an intermediate transfer medium, Modifications such as adjusting the transfer image and finally transferring it to a transfer paper are conceivable. The developing means 4 is provided with a developing roller electrode 43, and a liquid developer 45 whose main component is a dispersion liquid, which is toner and an insulating liquid, is fed from a liquid developer tank 41 by a pump 42, and from above the developing means 4. It is scattered toward the developing roller electrode 43.

The developing means 4 will be described in more detail with reference to the enlarged view of FIG. The developing means 4 includes a developing roller electrode 43 as a rotating body of the present invention. The surface of the developing roller electrode 43 is installed facing the image carrier 1 with a predetermined distance from the surface of the image carrier 1, for example, 0.05 to 1 mm, and the same direction as the surface of the image carrier 1 ( It is driven to rotate at a surface speed higher than the surface speed of the image carrier 1 in the direction of the arrow shown in FIG. 2, and the potential (image potential) of the image portion 1a of the electrostatic latent image and the potential of the background portion (background potential) of 1b. Is applied by the developing bias power source 46. Developing roller electrode 43
The liquid developer 45 is supplied to the gap between the opposed portions of the image carrier 1 and the image carrier 1, and the toner 45a in the liquid developer at the position opposed to the image carrier 1 is subjected to the action of the electric field there to carry the image in the image portion 1a. In the non-image portion 5, that is, the background portion 1b, the surface of the body 1 moves toward the surface of the developing roller electrode 43 by the electrophoretic phenomenon. As a result, a toner image corresponding to the image potential is formed on the image carrier 1. Since the developing roller electrode 43 is rotating in the same direction as the image carrier 1 (the direction of the arrow), the dispersion liquid 45 is formed at the exit of the interval between the developing roller electrode 43 and the image carrier 1.
Although b is determined by the surface condition of the surface of the image carrier 1 and the surface of the developing roller electrode 43, the speed difference, etc., it is divided into about 50% on the image carrier 1 and on the developing roller electrode 43.

The toner 45a and the dispersion liquid 45b on the surface of the image carrier 1 reach the surplus liquid removing means 5 next.
Of the developing roller electrode 43 to which the dispersion liquid 45b adheres unevenly, the apparent toner concentration changes as the developing condition after one rotation, and the toner 45a adhered to the surface of the electrode 43 adversely affects the developing electric field. In order to avoid giving and the like, the scraper 9 is brought into contact with the surface of the electrode 43 to remove the toner 45a and the dispersion liquid 45b.

By the way, since the toner 45a adheres to the surface of the electrode 43, the toner 45a easily aggregates and accumulates on the scraper 9 portion,
The toner 45a that has agglomerated during a long stop of the apparatus may solidify and become a motor load at the time of restart, or the load of the scraper 9 may become excessive and cleaning may not be completed and the image quality may be adversely affected. Therefore, in the present embodiment, the developing roller electrode 43 is provided close to the developing roller electrode 43, near the scraper 9 and on the upstream side in the rotation direction of the developing roller electrode 43.
A peeling electrode 91 to which a voltage sufficient to float the toner 45a from the surface is applied by a peeling bias power source 93 is provided. By the electric field formed between the peeling electrode 91 and the developing roller electrode 43, the toner 45a adhering to the developing surface is peeled off from the surface of the electrode 43 and attracted to the peeling electrode 91 side, and in the scraper portion, the developing roller electrode 43 is formed.
No toner adheres to the surface, and aggregation and accumulation of toner on the scraper portion is prevented.

On the other hand, on the image carrier 1 side, as described above, about 50% of the dispersant remains on the image carrier 1 at the outlet of the developing roller electrode 43, and the ratio of the dispersion liquid in the toner image is too large as it is. Since the cohesive force between the toners is weak, image deletion may occur at the time of transfer, and since many dispersion liquids including toner are also present in the background portion 1b, the surplus dispersion liquid in the image portion 1a and the background portion 1b before transfer. It is necessary to remove the toner and the dispersion liquid of 1. from the image carrier 1.

The surplus liquid removing means 5 is provided with a reverse squeeze roller 51 as a rotating body of the present invention, and the surface of the roller 51 is generally less than that of the surface of the image carrier 1.
It is installed facing the image carrier 1 with a gap of about 02 to 0.2 mm, and is driven to rotate in the direction opposite to the surface of the image carrier 1 (in the direction of the arrow shown in FIG. 2) to obtain the image potential of the electrostatic latent image. An intermediate bias potential with respect to the background potential is applied by the squeeze bias power source 52.

When the background portion 1b to which the image portion 1a excessively containing the dispersion liquid 45b and the dispersion liquid 45b containing a small amount of the toner 45a are attached to the excess liquid removing means 5,
A bridge formed by the liquid developer 45 is formed between the image carrier 1 and the reverse squeeze roller 51, and due to the action of the electric field due to the difference between the potential on the image carrier 1 and the bias potential applied to the reverse squeeze roller 51, Toner 45 of the image portion 1a
Since a force is applied to the surface of the image carrier 1 by the force a, the toner 45a is further in close contact with the image carrier 1 and the toner 45a.
The toner 45a not only removed by the developing roller electrode 43 but remaining on the background portion 1b can be further attracted to the reverse squeeze roller 51 side to clean the background portion 1b. it can. Furthermore, since both surfaces move in opposite directions, a shearing force acts in the liquid, and the surplus dispersion liquid 45b on the image carrier 1 reverses at a ratio determined by the speed of the both surfaces, the gap, the viscosity of the liquid and other physical properties. It is scraped off by the squeeze roller 51.

In order to provide the reverse squeeze roller 51 with a surplus liquid removing function, it is necessary to supply a substantially dry surface of the reverse squeeze roller 51 to the gap portion. The toner 45a and the dispersion liquid 45b on the reverse squeeze roller 51 are removed by being brought into contact with each other. However, as in the case of the developing roller electrode 43, the toner 45a may be aggregated and accumulated in the scraper 9 as well. Therefore, in this embodiment, it is sufficient to float the toner 45a from the surface of the reverse squeeze roller 51 by the peeling bias power source 93 in the vicinity of the reverse squeeze roller 51, in the vicinity of the scraper 9 and on the upstream side in the rotation direction of the reverse squeeze roller 51. A peeling electrode 91 to which various voltages are applied is attached. Due to the electric field formed between the peeling electrode 91 and the reverse squeeze roller 51, the toner 45a attached to the surface of the reverse squeeze roller 51 is peeled from the surface of the roller 51 and the peeling electrode 91.
The toner is attracted to the side and the toner is prevented from aggregating and accumulating in the scraper portion.

In the above description, as the peeling electrode 91,
The peeling electrode 91 for the developing roller electrode 43 is shown as a plate-shaped conductor, and the peeling electrode 91 for the reverse squeeze roller 51 is shown as a wire-shaped conductor, but the shape of the peeling electrode 91 is not limited, and will be described later. A plate shape, a linear shape, or any other suitable shape can be used depending on the mounting position, mounting space, etc. described. Therefore, although the linear peeling electrode 91 is used in all of the following embodiments, it is not limited to this. In addition, the applied voltage (positive / negative relationship) to each element is also shown in a very general example.
It can be reversed depending on the charging characteristics of the image carrier and the electrical specifications of each element, and at the same time, it can be changed by the system configuration such as the background irradiation method and image area irradiation method by the exposure means, and the reversal development by the developing means. This is the same in other embodiments of the present invention.

Next, an application example of the present invention to the shoe electrode developing system of the second embodiment will be described with reference to FIG. The developing shoe electrode 44 is 0.1 to 1 mm from the image carrier 1.
The liquid developers 45 are installed apart from each other, the liquid developer 45 is supplied from the upstream side in the rotation direction of the image carrier 1, and the developing bias power source 46 is provided.
The developing bias potential is applied by. Shoe electrode 44
Is in a stationary state without rotating like the developing roller electrode and is therefore extremely difficult to clean. Therefore, in this embodiment, the shoe electrode 44 is applied by applying a bias potential having the same polarity as the toner 45a to the shoe electrode 44. 45a on the surface of
To prevent adhesion. That is, the "background fog development" state in which the toner 45a also moves and adheres to the background portion 1b of the image carrier 1 is created.

The toner 45a and the dispersant 45b on the image carrier 1 which have come out of the developing shoe electrode 44 reach the excess liquid removing means 5 by the rotation of the image carrier 1. The excess liquid removing means 5 according to the present embodiment also includes a reverse squeeze roller 51, and the surface thereof has a gap of about 0.02 to 0.2 mm from the surface of the image carrier 1. The squeeze bias power supply 52 applies a bias potential intermediate between the image portion 1a and the background portion 1b of the electrostatic latent image, which is installed and rotated in the direction opposite to the surface of the image carrier 1. When the image portion 1a and the background portion 1b containing the excess dispersion liquid 45b move, the electric field due to the difference between the potential on the image carrier 1 and the bias potential applied to the reverse squeeze roller 51 causes the image portion 1a to move. The toner 45a is further pressed against the surface of the image carrier 1, and the toner 45a in the fog-developed state existing on the background portion 1b is attracted to the reverse squeeze roller 51 to clean the background portion 1b. Further, since both surfaces move in opposite directions, a shearing force acts in the liquid, and the surplus dispersion liquid 45b on the image carrier 1 is produced at a ratio determined by the speed of both surfaces, the gap, the viscosity of the liquid and other physical properties. It is scraped off by the reverse squeeze roller 51.

On the surface of the reverse squeeze roller 51, the dispersion liquid 45b and a large amount of toner 45a adhere,
The scraper 9 is provided to remove these for the reasons described above. Further, since the toner may be agglomerated in the scraper 9 as described above, in order to efficiently remove the toner 45a attached to the surface of the reverse squeeze roller 51, as in the case of the reverse squeeze roller 51 described above. In addition, the reverse squeeze roller 51, which is located upstream of the scraper 9 in the rotation direction of the reverse squeeze roller 51.
A peeling electrode 91 is provided at a position separated from the surface, and a voltage sufficient to float the toner 45a from the surface of the reverse squeeze roller 51 is applied to the peeling electrode 91 by the peeling bias power source 93, and thereby the reverse squeeze roller 51. The adhesion of the toner 45a to the toner can be released, and the toner 45a can be easily and reliably removed by the scraper 9.

Next, an example of application of the present invention to the spray developing system of the third embodiment will be described with reference to FIG. The spray developing system is provided with a dual-purpose roller electrode 53 as a rotating body of the present invention, which is a developing roller electrode and a reverse squeeze roller. The dual-purpose roller electrode 53 and the image carrier 1 are also provided.
The liquid developer 45 is supplied in the form of a spray in the gap between the and. The dual-purpose roller electrode 53 is generally installed with a gap of about 0.02 to 0.2 mm from the image carrier 1.
It is rotationally driven in the direction opposite to the surface of the image carrier 1 (in the direction of the arrow in the figure), a bias potential intermediate between the image portion 1a and the background portion 1b of the electrostatic latent image is applied, and it functions as a reverse squeeze roller and at the same time the developing roller. It also functions as an electrode. When the liquid developer 45 is supplied to the gap, an electric field due to the difference between the potential of the image carrier 1 and the bias potential applied to the dual-purpose roller electrode 53 from the simultaneous development squeeze roller bias power source 54 causes the image portion 1a to move. The toner 45a moves to the surface of the image carrier 1, and the toner 45a existing on the background portion 1b moves to the dual-purpose roller electrode 53 side. Further, since both surfaces move in opposite directions, a shearing force acts in the liquid, and the surplus dispersion liquid 45b on the image carrier 1 also serves as a ratio determined by the speed of both surfaces, the gap, the viscosity of the liquid and other physical properties. It is scraped off by the roller electrode 53. The dual-purpose roller electrode 53 and the power source 54 constitute both the developing means 4 and the excess liquid removing means 5.

On the surface of the dual-purpose roller electrode 53 of this embodiment,
As described above, the dispersion liquid 45b and a large amount of the toner 45a are attached, and the scraper 9 is provided to remove them for the reason described above. Also, this scraper 9
Since there is a possibility that toner will agglomerate in the area of 4 as described above, the toner 4 adhered to the surface of the dual-purpose roller electrode 53 as in the case of the developing roller electrode and the reverse squeeze roller described above.
In order to remove 5a efficiently, a peeling electrode 91 is provided on the upstream side of the scraper 9 in the rotation direction of the dual-purpose roller electrode 53 and at a position separated from the surface of the dual-purpose roller electrode 53. A voltage sufficient to float the toner 45a from the surface of the roller electrode 53 is applied by the peeling bias power supply 93, whereby the adhesion of the toner 45a to the dual-purpose roller electrode 53 is released, and the toner 45a can be easily removed by the scraper 9. And it can be done reliably.

As is clear from the above description of the first to third embodiments, the developing roller electrode 43 and the reverse squeeze roller 51 have almost the same electrical function. Therefore, an example in which the developing roller electrode 43 and the peeling electrode 91 for the reverse squeeze roller 51 according to the fourth embodiment are made common will be described with reference to FIG. In this figure, the structure of the image carrier 1, the developing roller electrode 43, the reverse squeeze roller 51,
Since the basic functions such as the supply of the liquid developer 45 are the same as those in the first embodiment, the description thereof will be omitted, and the requirements necessary for sharing the peeling electrode 91 will be described.

It is desirable that the peeling electrode 91 is close to the surface of the target roller for the purpose of reducing the load on the bias power source, and in order to make it about 1 mm, the developing roller electrode 4 is used.
8 and the reverse squeeze roller 51 should have a gap of about 2 mm or less. Here, the bias power source for both rollers is shown as sharing the developing bias power source 46 and the squeeze bias power source 52 in the figure, but it is also possible to use a separate power source having a common ground. The peeling electrode 9 is
In order to efficiently remove the toner 45a adhering to both roller surfaces, the scraper 9 is provided on the upstream side of the scraper 9 at a position separated by a distance such that approximately the same potential gradient can be obtained between both roller surfaces. A voltage sufficient to float the toner 45a is applied from the peeling bias power supply device 93. By the peeling electrode 91, the adhesion of the toner 45a on both roller surfaces can be released, and the scraper 9 can easily and surely remove the toner.

Next, referring to FIGS. 6 and 7, the electrode position,
The effect of the shape and the applied bias waveform will be described in detail.
In FIG. 6, a peeling electrode 91 for floating the toner 45a from the surface of the roller electrode 94 having at least one function of development and removal of excess liquid connected to the bias power source 95 for roller electrode, and a DC bias power source 93a are connected. It is an example. In this case, it is desirable to install the peeling electrode 91 in a state of not contacting the liquid developer 45. Otherwise, the toner 45a adheres to the peeling electrode 91 and cleaning means is required.

In the experiment, liquid developer 45 containing Isopar L (trademark) manufactured by Exxon Co. was used as a dispersion liquid 45b.
000 V / mm potential gradient (the relationship between the distance between the peeling electrode 91 and the roller-shaped electrode 94 and the bias potential is 1000 V / mm
mm), the toner 45a attached to the surface of the roller-shaped electrode 94 could be moved to the surface of the liquid developer layer.

FIG. 7 shows a peeling electrode 91 for floating the toner 45a from the surface of the roller-shaped electrode 94 having at least one function of development and removal of excess liquid, to which a bias power source 95 for roller-shaped electrode is connected. Power supply 93b
Is an example of connecting. In this case, the peeling electrode 91 can be placed in contact with the liquid developer 45. This is because the application of the AC bias promotes the stirring and re-dispersion of the toner 45a, and the electrode 94 can be effectively self-cleaned.

Experiments were carried out using a liquid developer 45 in which Isopar L (trademark) manufactured by Exxon Co. was used as a dispersion liquid 45b. As a result, a low frequency AC bias of 10 hertz or less and a potential of 500 V / mm peak value were obtained. By providing a gradient (the relationship between the distance between the peeling electrode 91 and the roller-shaped electrode 94 and the peak value of the AC bias voltage is 500 V / mm), the toner 45a adhering to the surface of the roller-shaped electrode 94 is peeled off, and a better condition is obtained. It could be recovered as the liquid developer 45 in a dispersed state. The effect of the stirring and re-dispersion can be further enhanced by replacing the AC bias power source 93b with the rectangular wave bias power source 93c. In other words, this means that good stirring and redispersion effects can be obtained even with a DC bias switched between ground and a low potential, and this point was also confirmed by experiments.

Although all the description of the embodiments has been made by applying the present invention to the electrophotographic copying machine or printer adopting the wet developing method, the present invention is not limited to the image applying various other wet developing methods. It can be applied to a forming device. That is, all apparatuses adopting a wet development method for developing an electrostatic latent image using a liquid developer, for example, a wet electrostatic plotter for directly developing an electrostatic latent image on insulating coated paper or photoconductor paper, etc. It is easy and effective to apply it to a plate making process, a printing proofer, etc., which is an applied technique of the electrophotographic method. Further, the present invention can be applied to a wet color copying machine without any trouble and can exert its effect.

[0034]

As described above, according to the wet image forming apparatus of the present invention, by providing the peeling electrode, the toner adhering to the surface of the rotating body is separated by electrophoresis prior to the cleaning of the surface of the rotating body by the scraper. Since it is floated from the surface of the rotating body, the load on the scraper is reduced and the cleaning condition is improved.At the same time, the toner accumulates and accumulates on the scraper edge, and the toner solidifies during the long-term stop, so It is possible to eliminate troubles due to increase of drive system load, occurrence of cleaning unevenness due to solidified toner intrusion, and collection of coarse toner in liquid developer for recovery / reuse due to falling of solidified toner by adding simple and low-priced parts. .

Further, a function of mixing the liquid developer collected by the application of the AC bias also occurs, and the liquid developer in a good dispersed state can be collected for reuse of the liquid developer.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an entire apparatus showing a first embodiment of a wet image forming apparatus to which the present invention is applied.

FIG. 2 is an enlarged view for explaining the developing device of the embodiment of FIG.

FIG. 3 is an enlarged view for explaining a developing device according to another embodiment of the present invention.

FIG. 4 is an enlarged view for explaining a developing device according to another embodiment of the present invention.

FIG. 5 is an enlarged view for explaining a developing device according to another embodiment of the present invention.

FIG. 6 is a diagram showing an example of a method of applying a voltage to a peeling device.

FIG. 7 is a diagram showing an example of a method of applying a voltage to a peeling device.

[Explanation of symbols]

 1 image carrier 1a image part 1b background part 4 developing means 5 surplus liquid removing means 9 scraper 43 developing roller electrode (rotating body) 45 liquid developer 45a toner 45b dispersion liquid 51 reverse squeeze roller (rotating body) 53 dual-purpose roller electrode ( 61) Transferring medium 91 Separation electrode 94 Roller-shaped electrode (rotating body)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Ida 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business Office (72) Inventor Yoshinori Machida 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business (72) Inventor Shinichi Utsumi 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business Office (72) Inventor Kiyohiro Shigeru, 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. Ebina Business Office

Claims (3)

[Claims] 1. A developing device comprising: a rotating image carrier on which an electrostatic latent image is formed; and a developing device for supplying liquid developer containing toner to the electrostatic latent image to develop the electrostatic latent image. Is a rotating body which is disposed in the vicinity of the image carrier and to which a bias potential is applied, a rotating body which comes into contact with the liquid developer, and a scraper which removes the liquid developer attached to the rotating body. In a wet image forming apparatus including: a potential in the direction of attracting toner on the rotating body is applied to a position near the rotating body, near the scraper, and on the upstream side in the rotating direction of the rotating body. A wet image forming apparatus, characterized in that a peeling electrode is provided. 2. The wet image forming apparatus according to claim 1, wherein a plurality of the rotating bodies are provided in the developing device, and the peeling electrodes are separately provided for the respective rotating bodies. 3. The wet image forming apparatus according to claim 1, wherein a plurality of the rotating bodies are provided in the developing device, and the peeling electrodes for the plurality of rotating bodies are shared by one peeling electrode. .