JPH06236114A - Wet type developing device and color image forming device using it - Google Patents

Abstract

PURPOSE:To provide a wet type developing device and a color image forming device using it, capable of increasing developing speed, simultaneously, cleaning a developing electrode and enhancing image quality, without fear of causing nonuniformity a density, color mixture, etc. CONSTITUTION:In the wet type developing device developing an electrostatic latent image formed on the surface of an electrostatic latent image carrier according to image information by using a liquid developer, the developing electrode 24 having at least one developing surface 24a formed in almost the same curvature as that of the surface of the electrostatic latent image carrier 11 and a cleaning member 26 cleaning the developing surface 24a of the developing electrode 24 are provided and the developing electrode 24 is constituted so as to rotate to developing position where the developing surface of the developing electrode 24 faces the electrostatic latent image carrier 1 via a prescribed gap and a cleaning position opposite to the cleaning member 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an image forming apparatus such as an electrophotographic copying machine or a printer, and is electrostatically charged by a liquid developer composed of toner particles dispersed in an insulating carrier liquid. The present invention relates to a wet type electrophotographic developing device that visualizes a latent image and a color image forming apparatus using the same.

[0002]

2. Description of the Related Art Generally, in a wet developing apparatus, a liquid developer composed of toner particles dispersed in an insulating carrier liquid is brought into contact with a photosensitive member on which an electrostatic latent image is formed, and It is configured to attach toner particles to an electrostatic latent image to form a visible image, and it is possible to use toner particles with a smaller particle size compared to a dry developing device, which enables high quality development. It has the feature of being

Further, in the above-mentioned wet type developing apparatus, if the liquid developer is simply brought into contact with the electrostatic latent image, it takes a long time until the toner particles adhere to the electrostatic latent image, so that the developing time is prolonged. Alternatively, since toner particles are concentrated on the fringe electric field portion having a strong electric field strength formed around the electrostatic latent image, only an image having a strong edge effect can be obtained. An electrode is provided to apply an appropriate electric potential to the developing electrode to shorten the developing time and obtain an image having no edge effect.

Conventionally, as such a wet developing device,
For example, as disclosed in Japanese Examined Patent Publication No. 62-51466, visualization is performed by passing a photoconductor having an electrostatic latent image formed on it over a plate-shaped or plate-shaped electrode containing a liquid developer. The ones designed to do are already proposed.

As the above-mentioned wet developing device, as disclosed in Japanese Patent Laid-Open No. 3-293690, a developing roller made of a conductive material is provided with a minute gap between the developing roller and the photosensitive member on which an electrostatic latent image is formed. It has already been proposed to dispose the liquid developer close to each other and supply the liquid developer to the minute gap to visualize the image.

Further, as the above-mentioned wet developing device, as disclosed in JP-A-4-134365, a developing solution is supplied to an image carrier having an electrostatic latent image formed on its surface to form a visible image. In a multicolor wet developing apparatus that performs the forming step for at least two colors, each color that stores a developing electrode that is arranged to face the image carrier and a developer that is supplied to the electrostatic latent image formed on the image carrier. Developer storage means for each,
Waste liquid storing means for storing the developer after developing the electrostatic latent image, and developer for supplying the electrostatic latent image formed on the image carrier with the developer of each color in an amount required for one development. A device configured to include a supply means has already been proposed.

[0007]

However, the above-mentioned prior art has the following problems. That is, in the wet developing device using the liquid developer as described above, since the developing speed (efficiency) mainly depends on the mobility of toner particles in the liquid, it is basically difficult to increase the speed. Have Further, since the mobility of toner particles in liquid depends on the electric field strength between the electrostatic image and the developing electrode, the surface smoothness of the developing electrode is important.

However, the above Japanese Patent Publication No. 62-5146.
As disclosed in Japanese Patent Laid-Open No. 6, No. 6, in the case of a developing device using a plate-shaped or plate-shaped electrode, the effective developing region can be made long, so that the developing efficiency is high and the speed can be increased. However, it is difficult to configure a small and inexpensive cleaning mechanism for removing the stains on the electrodes due to the adhesion of excess developer after development, and it is difficult to configure the electrostatic charge image due to stains on the electrodes and the electric field strength between the developing electrodes. There is a problem in that unevenness occurs, density unevenness and streaks occur in a developed image, and the image quality is adversely affected.

Further, as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-293690, in the case of a wet type developing device using a roller type developing electrode, the developing electrode roller is rotated to scrape a doctor blade or the like. Although it is possible to clean with, and it is possible to deal with dirt on the electrode, the development electrode is in the shape of a roller, so the effective development area that is close to the photoreceptor and contributes to development is narrow, so the development speed is increased. Has a problem that it is difficult.

Further, as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 4-134365, the developing solution of each color is sequentially supplied from one developing solution supplying means of two or more colors to one developing device,
In the case of a developing device that forms a color image, it is possible to reduce the size of the device, reduce the cost, and increase the system speed, but there is a risk that color mixture will occur due to residual toner remaining on the developing electrodes. It has a problem.

Therefore, the present invention was made in order to solve the above-mentioned problems of the prior art. The object of the present invention is to make it possible to increase the developing speed and to clean the developing electrodes. Therefore, it is an object of the present invention to provide a wet type developing device capable of achieving high image quality without the risk of density unevenness, color mixture, etc., and a color image forming apparatus using the wet type developing device.

[0012]

A wet developing apparatus according to the present invention develops an electrostatic latent image formed on the surface of an electrostatic latent image carrier according to image information by using a liquid developer. The wet developing apparatus includes a developing electrode having at least one developing surface formed to have substantially the same curvature as the surface of the electrostatic latent image carrier, and a cleaning member for cleaning the developing surface of the developing electrode. A developing position where the developing surface of the electrode faces the electrostatic latent image carrier with a predetermined gap,
It is configured to be rotatable to a cleaning position facing the cleaning member.

Further, the developing device is provided with, for example, liquid developer supplying means for selectively supplying liquid developers of different colors to the developing surface of the developing electrode located at the developing position. To be done.

On the other hand, in the color image forming apparatus according to the present invention, the electrostatic latent image formed on the surface of the electrostatic latent image carrier according to the image information is formed by using a plurality of liquid developers of different colors. In a color image forming apparatus for developing and forming a color image, a developing device for developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier is substantially the same as the surface of the electrostatic latent image carrier. A developing electrode having at least one developing surface formed in a curvature, a cleaning member for cleaning the developing surface of the developing electrode, and a developing surface of the developing electrode positioned at the developing position, liquid development of a plurality of different colors A liquid developer supplying means for selectively supplying the developer, a developing position where the developing surface of the developing electrode faces the electrostatic latent image carrier with a predetermined gap, and a cleaning facing the cleaning member. Rotate to position When developing with liquid developers of different colors by the developing device, the developing electrode is rotated to clean the used developing surface with a cleaning member, and the developing electrode is developed after cleaning. The surface is configured to always develop the electrostatic latent image.

As the electrostatic latent image carrier, for example, a photoconductor sheet carried on a drum-shaped carrier is used.

This photoreceptor sheet is formed, for example, by coating a thin film conductive support made of aluminum or the like with an inorganic photoconductor such as zinc oxide or titanium oxide.

However, the electrostatic latent image bearing member is not limited to this, and a photosensitive drum or a belt-shaped photosensitive member may be used as a matter of course. There are things.

As the inorganic photoconductor, "Electro
Photogramy "R. M. Schaffert
Written by FocalPress (London), (1
1975) various inorganic compounds disclosed on pages 260 to 374 and the like are typical. Specific examples include zinc oxide, zinc sulfide, cadmium sulfide, selenium, and a selenium-tellurium-arsenic alloy. In addition, amorphous silicon or the like can be used.

As the organic photoconductor, there are a wide range of well-known organic semiconductors. Specifically, the Research is
Disclosure Magazine # 10938 (May 1973)
There are substances described in "Electrophotographic Elements, Materials and Processes", etc. from page 61 of the month issue. For example, Poly-N
An electrophotographic photoconductor comprising vinylcarbazole and 2,4,7-trinitrofluoren-9-one (US Pat. No. 3,484,237), poly-N-vinylcarbazole sensitized with a pyrylium salt dye. (Japanese Patent Publication Sho 48-2
5658), an electrophotographic photoreceptor containing an organic pigment as a main component (JP-A-47-10735), and an electrophotographic photoreceptor in which copper phthalocyanine is dispersed in a resin (JP-B-52-1667).
No.) etc.

[0020]

In the wet type developing apparatus according to the present invention, the developing electrode having at least one developing surface formed with substantially the same curvature as the surface of the electrostatic latent image carrier, and the cleaning for cleaning the developing surface of the developing electrode. A member, and the developing electrode is configured to be rotatable between a developing position, the developing surface of which faces the electrostatic latent image carrier with a predetermined gap, and a cleaning position, which faces the cleaning member. Therefore, since the developing electrode has at least one developing surface formed with substantially the same curvature as the surface of the electrostatic latent image bearing member, this developing surface causes a gap between the developing electrode and the electrostatic latent image bearing member. Therefore, a sufficient development electric field can be formed, and clear and high-quality development can be performed at high speed by the liquid developer. Further, the developing electrode is configured such that its developing surface is rotatable between a developing position facing the electrostatic latent image carrier with a predetermined gap and a cleaning position facing the cleaning member. Therefore, the used developing surface can be cleaned by the cleaning member, and there is no risk of density unevenness, color mixing, etc., and high-quality developing can be performed from this surface as well.

Further, in the color image forming apparatus according to the present invention, the developing device for developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier is substantially the same as the surface of the electrostatic latent image carrier. A developing electrode having at least one developing surface formed in a curvature, a cleaning member for cleaning the developing surface of the developing electrode, and a developing surface of the developing electrode positioned at the developing position, liquid development of a plurality of different colors A liquid developer supplying means for selectively supplying the developer, a developing position where the developing surface of the developing electrode faces the electrostatic latent image carrier with a predetermined gap, and a cleaning facing the cleaning member. When developing with liquid developers of different colors by the developing device, the developing electrode is rotated to clear the used developing surface with a cleaning member. Since the electrostatic latent image is constantly developed by the developing surface of the developing electrode after cleaning and cleaning, it goes without saying that high-speed and high-quality development can be performed as in the wet developing device. Even if there is only one developing device itself, a color image can be formed well, and the color image forming device can be downsized.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

FIG. 3 shows an electrophotographic copying machine to which an embodiment of the wet type developing apparatus according to the present invention is applied.

This electrophotographic copying machine uses a photoreceptor sheet, and includes a charging step, an image exposing step, a prewetting step, a wet developing step, a squeeze step, and a drying step.
It is configured to copy an image of an original by an electrofax method (EF method) including a charge removing step and a cleaning step. The image forming apparatus to which the wet type developing apparatus according to the present invention is applied may of course form an image by another method.

In FIG. 3, reference numeral 11 denotes a photoconductor sheet carrying drum capable of carrying the photoconductor sheet 1 on its surface. The photoconductor sheet carrying drum 11 is a cylindrical conductive member made of aluminum or the like. It is composed of a base body, and is rotationally driven at a predetermined speed in the direction of arrow A by a driving means (not shown). Further, the photosensitive sheet 1 is supplied to the surface of the photosensitive sheet carrying drum 11 from a supply cassette (not shown), and the conveying roller 10
Thus, the photosensitive sheet 1 is conveyed at a predetermined timing. Then, on the surface of the photoconductor sheet supporting drum 11, the photoconductor sheet 1 is subjected to electrostatic force by a charger or mechanical force by a gripper.
Is carried in a wound state.

As the photoconductor sheet 1, for example, a thin film conductive support made of aluminum or the like and coated with zinc oxide or titanium oxide, which is an inorganic photoconductor, is used. The photoconductor sheet 1 is held on the surface of the photoconductor sheet carrying drum 11, and the thin film conductive support is in contact with the drum 11, and is grounded via the photoconductor sheet carrying drum 11. It is designed to be connected to.

Further, the drum 11 for carrying the photoconductor sheet.
The surface of the photoconductor sheet 1 carried on the sheet is uniformly charged to a predetermined potential by the primary charger 2 composed of a scorotron or the like, and then the image of the document 13 is scanned and exposed.
An electrostatic latent image is formed.

That is, the image of the original document 13 placed on the platen glass 12 is illuminated by the light source lamp 14, and the reflected light image from the original document 13 is reflected by the scanning mirror 15 having a slit, the optical filter 19, and the reflection. Mirror 16
Is exposed on the photoconductor sheet 1 through
An electrostatic latent image corresponding to the image of the original 13 is formed on the top. At that time, the light source lamp 14 and the scanning mirror 15 are
The entire surface of the image of the document 13 is scanned along the right direction in the drawing at a predetermined scanning speed corresponding to the rotation speed of the drum 11 for carrying the photoconductor sheet. The photosensitive sheet 1 carried on the working drum 11 is scanned and exposed over the entire surface.

Next, the pre-wetting liquid is applied by the pre-wetting means 4 to the surface of the photosensitive sheet 1 on which the electrostatic latent image corresponding to the image of the original 13 is formed as described above. The prewetting means 4 is rotatably arranged in the prewetting liquid storage portion 4a containing the prewetting liquid and in the prewetting liquid storage portion 4a, and is disposed close to the photoconductor sheet 1 via a minute gap. Alternatively, the roll-shaped member 4b is provided so as to be in contact with the roll-shaped member 4b. Then, the prewetting means 4 holds the prewetting liquid on the surface of the rotationally driven roll-shaped member 4b due to the viscosity of the liquid, and the roll-shaped member 4b makes the prewetting liquid uniform on the surface of the photoreceptor sheet 1. It is designed to be applied. In the non-contact type in which the roll-shaped member 4b of the pre-wetting means 4 does not contact the surface of the photosensitive sheet 1,
The amount of the prewetting liquid supplied between the gaps can be adjusted by the rotation speed of the roll-shaped member 4b. As the prewetting liquid, a carrier liquid used in a developing device described later can be used as it is.

As described above, by performing the pre-wetting step, it is possible to prevent the background stain which is caused by the unnecessary toner which is electrically or physically adsorbed to the non-image portion during the development.

As the above-mentioned pre-wetting means, other than that, a blade or a sprayer can be used. Generally, the non-contact type is more effective because it does not disturb the electrostatic latent image. Is.

Next, the electrostatic latent image on the photoconductor sheet 1 coated with the prewetting liquid is the drum 1 for carrying the photoconductor sheet.
1 is visualized by one of the developing devices 35 to 38 of the wet type developing device 5. These four wet developing devices 35 to 38 are arranged so as to be movable along the horizontal direction, and one selected developing device is vertically moved to a developing position close to the photosensitive sheet carrying drum 11. It is possible to move along.

Further, the squeeze means 6 removes the excess developer from the photosensitive sheet 1 which has undergone the developing process. As the squeeze means 6, for example, an air knife device having an air ejecting portion facing the image forming area is used. By ejecting compressed air from the air ejecting portion, the excess of the adhering material on the photosensitive sheet 1 is removed. It is possible to wash away the developing solution and prevent the background stain due to the toner contained in the excess developing solution. At the same time, the squeeze means 6 also provides a drying effect.

In addition to the above, as the squeeze means 6, a roll-shaped member is brought into close proximity to the photoconductor sheet with a minute gap, and the roll-shaped member is rotated to perform liquid draining by utilizing the viscosity of the liquid. It is possible to use a device or a device for squeezing excess developer by bringing a roll-shaped member into contact with the photosensitive sheet and rotating (co-rotating) at the same speed as the photosensitive sheet.

The photosensitive sheet 1 after the squeeze process is dried by the drying means 7 which blows warm air or dry air supplied from a blower (not shown), and the developing toner is fixed on the photosensitive sheet. .

Further, the photoconductor sheet 1 is provided with a corona charger 8 arranged so as to face the photoconductor sheet 1.
Receives an AC corona discharge, and the residual charges on the photoconductor sheet 1 are neutralized. As the charge removing unit 8, a light charge removing unit or the like may be used which irradiates the photoconductor with light by a halogen lamp or the like arranged so as to face the photoconductor sheet 1 to remove residual charges on the photoconductor sheet 1.

These processes are repeated as many times as necessary for the number of colors, after which the photoconductor sheet 1 is peeled off by the peeling claws 22 and conveyed by the conveying belt 23 to the discharge tray provided outside, for carrying the photoconductor sheet. The surface of the drum 11 is cleaned by the cleaning roller 9 driven by a driving unit (not shown), and the whole process is completed.

By the way, in this embodiment, the wet developing devices 35 to 38 have a developing electrode having at least one developing surface formed to have substantially the same curvature as the surface of the electrostatic latent image carrier, and the developing electrode of this developing electrode. A cleaning member for cleaning the developing surface is provided, and the developing electrode can be rotated between a developing position where the developing surface faces the electrostatic latent image carrier with a predetermined gap and a cleaning position facing the cleaning member. Is configured to be.

FIG. 1 is a block diagram of a wet developing apparatus according to an embodiment of the present invention.

The wet developing device 5 has an apparatus main body 20 formed in the shape of an elongated rectangular parallelepiped box, and the upper end of the apparatus main body 20 is opened over the entire surface. A developing electrode 24 is arranged in the opening of the apparatus main body 20 on the upstream side in the moving direction of the photosensitive sheet 1, and a predetermined developing bias voltage is applied to the developing electrode 24 by a high voltage power source (not shown). It is supposed to be done. As shown in FIG. 1, the developing electrode 24 has a curved surface 24a having the same curvature as the peripheral surface of the photosensitive sheet carrying drum 11,
It has four surfaces on its outer periphery and is formed in an elongated rectangular parallelepiped shape having a substantially square cross section. Further, as shown in FIG. 2, plate-shaped spacers 2 are provided on both ends of the developing electrode 24.
5 is attached to each curved surface 2 of the developing electrode 24.
4a, the gap between the photosensitive sheet 1 carried on the surface of the photosensitive sheet carrying drum 11 via the spacer 25 is set to a predetermined value (for example, 100 to 500 μm). .

Further, the developing electrode 24 is rotatably arranged by a driving means (not shown), and when the developing electrode 24 is rotationally driven at a predetermined timing, the different curved surface 24a of the developing electrode 24 faces the photoconductor sheet 1. It is configured so as to move to a developing position. At this time, since the developing electrode 24 is formed in a substantially square shape in cross section, when rotating, the rotating shaft of the developing electrode 24 is separated from the surface of the photosensitive sheet carrying drum 11 to cause the developing electrode 24 to rotate. The rotation of is possible.

Further, a cleaning member 26 for cleaning the curved surface 24a of the developing electrode 24 is arranged below the developing electrode 24. As the cleaning member 26, an elastic roll-shaped member 26 is used as the spring 2.
7 is pressed against the developing surface 24a of the developing electrode 24, and the roll-shaped member 26 is rotationally driven by a driving unit (not shown), thereby removing the unnecessary developer adhering to the developing surface 24a of the developing electrode 24. ing. The roll-shaped member 26 moves downward against the elastic force of the spring 27 as the developing electrode 24 rotates. As the roll-shaped member 26, for example, a sponge-shaped member, a brush-shaped member, or a rubber member is used.

As the cleaning member 26, a scraping cleaning member such as a doctor blade may be used instead.

A cleaning member 26 for the developing electrode 24.
Are supported on an intermediate plate 28 arranged at an intermediate position in the developing device main body 20. A large number of fine holes are formed in the intermediate plate 28. A filter 29 is arranged on the lower surface of the intermediate plate 28, and the toner removed by the roll-shaped member 26 is agglomerated and cannot be redispersed. The unnecessary toner is removed by the filter 29.

Below the developing device main body 20,
A developer storage section 30 for storing the developer is provided,
The developing solution storage unit 30 contains a developing solution in which toner particles of a predetermined color are dispersed in an insulating carrier liquid. Then, the developing solution in the developing solution reservoir 30 is supplied to the nozzle 32 by the developing solution supply pump 31, and the developing surface 24 of the developing electrode 24 is supplied from the nozzle 32.
It is supplied evenly on a.

Further, in the opening of the developing device main body 20, a conductive squeeze roll 33 is provided downstream of the developing electrode 24 in the moving direction of the photosensitive member sheet 1.
And it is arranged with a minute gap. The squeeze roll 33 can be rotated in the direction of the arrow in the drawing by a driving device (not shown), and is for draining the excess developing solution by utilizing the viscosity of the solution.
Further, a bias voltage equivalent to the developing bias voltage is applied to the squeeze roll 33, which assists the development of a portion where the development has not been sufficiently performed and electrically attracts the excess toner to the squeeze roll 33 side. Thus, the photoconductor sheet 1 discharged from the developing process
The toner density in the developer remaining on the top is reduced to prevent background fog that occurs after the developing process.

Further, the unnecessary developer adhering to the squeeze roll 33 is removed by the doctor blade 34 supported on the intermediate plate 28.
The squeeze roll 33 is in contact with the surface of the photoconductor sheet carrying drum 11 via the tracking roll 39, and the photoconductor sheet carried on the surfaces of the squeeze roll 33 and the photoconductor sheet carrying drum 11 is held. 1
And are arranged to face each other with a predetermined gap.

In this embodiment, four wet developing devices 35 to 38 having the above-described structure are provided.
Each of the wet developing devices 35 to 38 has a yellow color of 35.
(Y), magenta 35 (M), cyan 37 (C), and black 38 (B) developers are used. Further, in the wet developing devices 35 to 38, as described above, the required developing device is located at the developing position 5 by the slide mechanism and retract mechanism (not shown) and their drive and control devices.
It is supposed to be moved to.

At that time, during the retraction, the photosensitive sheet 1 and the wet developing device are positioned by the tracking roll 39 attached to the squeeze roll 33 and the developing electrode 24.
By means of blade-shaped spacers 25 attached to the ends of the.

In the electrophotographic copying machine to which the wet developing apparatus according to this embodiment is applied with the above-mentioned structure, the electrostatic latent image on the photosensitive sheet is developed as follows. That is, in this electrophotographic copying machine, as shown in FIG.
Image is exposed to form an electrostatic latent image according to the image information of the original 13, and the electrostatic latent image formed on the photoconductor sheet 11 is moved to the developing position by a predetermined wet developing device 3
5 to 38 are developed using a developing solution and visualized.

In this wet developing device, as shown in FIG. 1, the developing solution in the developing solution reservoir 30 is supplied to the nozzle 32 by the developing solution supply pump 31, and the nozzle 32 is provided.
Is supplied to the developing area between the developing surface 24a of the developing electrode 24 and the photosensitive sheet 1. Then, the developing electrode 24
The toner particles in the developing diameter supplied to the developing area between the developing surface 24a of the developing electrode 24 and the photosensitive sheet 1 are generated by the developing electric field formed between the developing surface 24a of the developing electrode 24 and the photosensitive sheet 1. The electrostatic latent image on the photoconductor sheet 1 is moved and adhered to the electrostatic latent image to be developed.

At this time, the developing electrode 24 has the developing surface 24a formed to have the same curvature as the surface of the photosensitive sheet carrying drum 11 carrying the photosensitive sheet 1.
A sufficient developing electric field is formed between the developing surface 24a and the photoconductor sheet 1, and clear and high-quality development can be performed at high speed by the liquid developer. Further, the developing electrode 24 is configured such that the developing surface 24a thereof is rotatable between a developing position where the developing surface 24a faces the photosensitive sheet 1 with a predetermined gap and a cleaning position where the developing member faces the cleaning member 26. Since the used developing surface 24a can be cleaned by the cleaning member 26, there is no possibility that density unevenness or color mixture occurs, and high-quality development can be performed from this surface as well.

FIG. 4 shows a second embodiment of the present invention. The same parts as those of the first embodiment are designated by the same reference numerals. The structure of the charge eliminating means and the like is different from that of the first embodiment.

That is, as the image exposure means, the image of the original 13 placed on the platen glass 12 is read by the scanner 17, and the image data read by the scanner 17 is subjected to signal processing,
Alternatively, a digital exposure unit is used which exposes image data supplied from a host computer onto the photosensitive sheet 1 using the ROS device 18 by laser exposure.

The ROS device 18 is a semiconductor laser and a control unit for controlling the output state of the semiconductor laser, a condenser lens, a scanning lens, a reflection mirror, and a laser ON / OFF.
It is composed of an AOM (acousto-optical light converting element) for performing the above, a polygon mirror, and a memory 19 for storing image data.

As the semiconductor laser, for example, Al
-Ga-As lasers can be used. A laser beam emitted from this semiconductor laser is applied to the AOM via a condenser lens. In addition, ultrasonic waves of different frequencies generated according to the image data stored in the memory 19 are supplied to the AOM. As a result, the laser beam is diffracted in different directions depending on the frequency of the ultrasonic wave, and the light intensity is modulated by turning on / off the laser or the intermediate thereof. The modulated laser beam is condensed by a condenser lens, is incident on a polygon mirror that rotates at high speed via a reflection mirror, and is irradiated onto the surface of the photoconductor sheet via the scanning lens and the reflection mirror. The photoconductor sheet irradiated with the laser beam becomes electrically conductive, and the electric charges charged on the surface are removed, so that an electrostatic latent image is formed on the photoconductor sheet 1.

Other than this, as the digital exposure system, a system using a liquid crystal shutter array, a system using an LED array, or the like can be used.

Further, in this embodiment, as the static elimination means,
A halogen lamp 21 arranged so as to face the photoconductor sheet 1 is used.

The other constructions and operations are the same as those of the first embodiment, and the explanation thereof will be omitted.

FIG. 5 shows a third embodiment of the present invention. The same parts as those of the first embodiment will be designated by the same reference numerals and will be described. In this embodiment, a wet developing device is used. Also, the structure of the image exposing means is different from that of the first embodiment.

That is, in this embodiment, only one wet developing device is arranged, and this one wet developing device enables color development of four colors. The structure of the wet developing device itself is basically the same as that of the first embodiment. However, in this wet developing device, from the plurality of developing tanks 45 to 48, Y, M, C, K It is possible to supply the developer of each color from four nozzles without mixing the colors. At this time, the selection of each developer pump and the supply amount of the developer required for one development are optimally performed by the developer pump drive device and the control device 40, and the liquid developer used for the development is the waste liquid. Is stored in the storage layer 41 as.

The image exposure means is a digital exposure system as in the second embodiment.

In this embodiment, similarly to the first embodiment, the developing electrode 24 has the developing surface 24a formed with the same curvature as the surface of the photosensitive sheet carrying drum 11 carrying the photosensitive sheet 1. Since it has this developing surface 24a
Thus, a sufficient developing electric field can be formed between the photosensitive sheet 1 and the liquid developer, and clear and high-quality development can be performed at high speed by the liquid developer. Further, the developing electrode 24 is configured such that the developing surface 24a thereof is rotatable between a developing position where the developing surface 24a faces the photosensitive sheet 1 with a predetermined gap and a cleaning position where the developing member faces the cleaning member 26. Since the used developing surface 24a can be cleaned by the cleaning member 26, there is no possibility that density unevenness or color mixture occurs, and high-quality development can be performed from this surface as well.

In this embodiment, the developing device for developing the electrostatic latent image formed on the surface of the photoconductor sheet 1 has at least one developing surface formed with substantially the same curvature as the surface of the photoconductor sheet 1. Developing electrode 24 having one and this developing electrode 24
Cleaning member 2 for cleaning the developing surface 24a of
6 and the developing surface 2 of the developing electrode 24 located at the developing position
4a is provided with liquid developer supplying means 45 to 48 for selectively supplying liquid developers of a plurality of different colors, and the developing electrode 24 has its developing surface with the photosensitive sheet 1 via a predetermined gap. The developing position facing each other and the cleaning member 26
When the developing device is configured to be rotatable to a cleaning position opposite to the developing device and developing with liquid developers of different colors by the developing device, the developing electrode 24 is rotated to remove the used developing surface 24a from the cleaning member 26. And the developing surface 24 of the developing electrode 24 after cleaning.
Since the electrostatic latent image is always developed by a, the developing device itself can perform high-speed and high-quality development as in the wet developing device.
In any case, it is possible to favorably form the color image, and the color image forming apparatus can be downsized.

The rest of the configuration and operation are the same as in the first embodiment, so a description thereof will be omitted.

[0066]

According to the present invention, which has the above-described structure and operation, the developing speed can be increased, the developing electrode can be cleaned, and uneven density or color mixture may occur. In addition, it is possible to provide a wet-type developing device capable of achieving high image quality and a color image forming apparatus using the same, which can be downsized.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing an embodiment of a wet developing device according to the present invention.

FIG. 2 is a plan view showing a developing electrode of the same apparatus.

FIG. 3 is a block diagram showing an electrophotographic copying machine to which an embodiment of the wet developing apparatus according to the present invention is applied.

FIG. 4 is a block diagram showing an electrophotographic copying machine to which an embodiment of a wet developing apparatus according to the second embodiment of the present invention is applied.

FIG. 5 is a block diagram showing an electrophotographic copying machine to which an embodiment of a wet developing apparatus according to the third embodiment of the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photoconductor sheet, 20 Developing device main body, 24 Developing electrode, 24a Developing surface, 26 Cleaning member, 33
Squeeze roll.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyohiro Shigehiro 2274 Hongo, Ebina, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (3)

[Claims] 1. A wet developing apparatus for developing an electrostatic latent image formed on the surface of an electrostatic latent image carrier according to image information by using a liquid developer, wherein A developing electrode having at least one developing surface formed to have substantially the same curvature as the surface and a cleaning member for cleaning the developing surface of the developing electrode are provided, and the developing electrode is an electrostatic latent image carrier. A wet developing device characterized in that it is rotatable between a developing position facing a predetermined gap and a cleaning position facing the cleaning member. 2. A liquid developer supply means for selectively supplying liquid developers of a plurality of different colors to the developing surface of the developing electrode located at the developing position. The wet developing device according to the item. 3. A color for forming a color image by developing an electrostatic latent image formed on the surface of an electrostatic latent image carrier according to image information using a plurality of liquid developers of different colors. In the image forming apparatus, a developing device for developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier is provided with at least a developing surface formed to have substantially the same curvature as the surface of the electrostatic latent image carrier. Developing electrode, a cleaning member for cleaning the developing surface of the developing electrode, and a liquid developer for selectively supplying liquid developers of different colors to the developing surface of the developing electrode located at the developing position. A supply unit, and the developing electrode is configured to be rotatable between a developing position whose developing surface faces the electrostatic latent image carrier with a predetermined gap and a cleaning position facing the cleaning member. Depends on developing device When developing with a color liquid developer, the developing electrode is rotated to clean the used developing surface with a cleaning member, and the electrostatic latent image is always developed with the developing surface of the developing electrode after cleaning. A color image forming apparatus characterized by the above.