JP2001282000A - Wet electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet electrophotographic device capable of obtaining stable image output by preventing toner particles in liquid developer from intruding into a contact part between a photoreceptor drum and a contact roller. SOLUTION: This wet electrophotographic device is constituted of the photoreceptor drum 1, an electrifier 2-1, a laser exposing source 3-1, a developing means 4-1, a solvent removing means 5-1 removing an excess carrier solvent, an intermediate transfer roller 6, and a pressure roller 7; and the developing means 4-1 is constituted of a developing roller 8-1, a liquid storage part 9-1 for storing the liquid developer, and the contact roller 13-1 press-contacting with the area of the drum 1 where the liquid developer is not supplied. The storage part 9-1 is provided with a tank in which the liquid developer supplied to the roller 8-1 is stored and a tank in which the carrier solvent supplied to the roller 13-1 is stored. The liquid developer is separated from the carrier solvent by a partition plate 14 in the storage part 9-1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet electrophotographic apparatus for forming and outputting an image by an electrophotographic method using a liquid developer.

[0002]

2. Description of the Related Art A wet electrophotographic apparatus using a liquid developer comprising toner particles as a solid component and a carrier solvent as a liquid component has advantages which cannot be realized by a dry electrophotographic apparatus. Is being reviewed. For example, it is possible to use a very fine toner having a submicron size, so that high image quality can be realized, and sufficient image density can be obtained with a small amount of toner, so that it is economical and has a texture similar to that of printing (for example, offset printing). What can be achieved is the main advantage of wet electrophotography over dry process. On the other hand, in a conventional wet electrophotographic apparatus, a developing roller that holds a liquid developer on the surface and supplies the liquid developer to a photosensitive drum, and a liquid developer that is provided near the developing roller and is provided near the developing roller, In order to dispose a solvent removing roller for removing unnecessary carrier solvent and the photosensitive drum, the developing roller or the solvent removing roller is in contact with both sides of the non-image portion of the photosensitive drum surface. A guide roller arranged coaxially is provided. However, since the surface of the guide roller and the surface of the photosensitive drum are always in contact, the liquid developer containing toner particles always exists on the surface of the guide roller and the surface of the photosensitive member. The toner particles are present on the guide roller surface or at a support shaft supporting the guide roller and at a receiving portion of the support shaft in contact with and supporting the support shaft. There was a possibility that a problem of hindering normal rotation of the drum would occur.

In Japanese Patent Application Laid-Open No. H11-143242, a liquid developer absorber is arranged near a developing roller or a guide roller of a solvent removing roller to absorb the liquid developer, and the inside of the guide roller support bearing portion is absorbed. To prevent toner from entering. However, the surface of the photosensitive drum and the surface of the guide roller are always in a solid contact state, and if this state continues, surface deterioration occurs. Due to this surface deterioration, the gap between the developing roller or the solvent removing roller and the photosensitive drum fluctuates, causing a problem that image unevenness or the like occurs.

[0004] Further, the solvent removing roller requires a carrier solvent to remove excess liquid developer present on the surface of the photosensitive drum. In the solvent removing roller that rotates in the opposite direction to the photosensitive drum, the meniscus of the liquid developer formed between the photosensitive drum and the solvent removing roller causes
Pressure is always generated in the gap, and as a result, the solvent removing roller removes excess carrier solvent on the photosensitive drum from the photosensitive drum.

That is, if this meniscus does not occur, no pressure is generated between the photosensitive drum and the solvent removing roller, and as a result, the effect of removing the carrier solvent is lost.

Therefore, in Japanese Patent Application Laid-Open No. H11-143242, a meniscus cannot be generated between the surface of the solvent removing roller and the surface of the photosensitive drum. The carrier solvent could not be removed, and as a result, there was a possibility of adversely affecting processes such as offset transfer in the subsequent stage.

[0007]

As described above, in the conventional wet electrophotographic apparatus, the image area on the surface of the photosensitive drum is always located between the surface of the photosensitive drum and the guide roller of the developing roller or the guide roller of the solvent removing roller. When a liquid developer containing toner particles having the same concentration as that of the toner exists, the toner particles adhere to the surface of the guide roller or the surface of the photosensitive drum in contact with the photosensitive drum, and the toner particles adhere to the receiving portion of the guide roller. There has been a problem in that the rotation of the drum is hindered, image deterioration and the life of the photosensitive drum and the guide roller are shortened.

In Japanese Patent Application Laid-Open No. 11-143242, the surface of the photosensitive drum and the guide roller are always in solid contact with each other. The service life of the photosensitive drum and the guide roller may be shortened. Furthermore, since the carrier solvent necessary for the solvent removing roller does not exist in order to remove the excess carrier solvent on the surface of the photosensitive drum supplied by the developing roller, the excess carrier solvent cannot be removed. In addition, there is a risk of causing image deterioration.

In view of the above, the present invention has been made in view of the above-described conventional problems, and prevents the output image from deteriorating by preventing toner particles from entering between the photosensitive drum and each guide roller. It is another object of the present invention to provide a wet electrophotographic apparatus that can shorten the life of photosensitive drums and guide rollers.

[0010]

In order to achieve the above object, a wet electrophotographic apparatus according to the present invention comprises a latent image holder which is rotatable in a certain direction for holding an electrostatic latent image on a surface thereof, A latent image forming means for forming an electrostatic latent image on the latent image carrier, a liquid developer comprising a carrier solvent for visualizing the electrostatic latent image and toner particles dispersed in the carrier solvent Developing means having a liquid developer storage unit for storing the liquid developer, and a developing roller provided in non-contact with the latent image holding member and supplying the liquid developer of the liquid developer storage unit to the surface of the latent image holding member. A transfer unit for transferring a visible image visualized by the developing unit onto an image carrier, wherein the developing unit further comprises a carrier solvent storing only the carrier solvent. A storage section, which is in contact with the latent image holding member; The carrier solvent for the carrier solvent reservoir provided on the developing roller coaxially, characterized by comprising a contact roller to be supplied.

Next, the electrophotographic apparatus of the present invention is characterized by comprising the following. Note that the toner particle concentration of the liquid developer is higher than that of the carrier solvent.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a first embodiment of the electrophotographic apparatus of the present invention. As shown in the configuration diagram of the first embodiment in FIG. 1, a wet electrophotographic apparatus is configured such that an organic or electro-conductive device is rotatable in a certain direction for holding an electrostatic latent image on a surface thereof. A photosensitive drum 1 serving as a latent image holding member provided with an amorphous silicon-based photosensitive layer, and a scorotron charger 2 serving as a latent image forming means disposed separately from the photosensitive drum 1 for each color (Y, M, C, Bk). -1
(2-2, 2-3, 2-4), a laser exposure source 3-1 as a latent image forming means for uniformly irradiating the charged area with exposure light.
(3-2, 3-3, 3-4), liquid development comprising a hydrocarbon-based carrier solvent and toner particles dispersed in the carrier solvent, which is disposed separately from the photosensitive drum 1 Developing means 4-1 (4-2, 4-
3, 4-4), a solvent removing unit 5-1 (5-2, 5-3, 5-4) that is disposed apart from the photosensitive drum 1 and removes excess carrier solvent existing on the surface of the photosensitive drum 1. And an intermediate transfer roller 6 having a heating device therein and serving as a transfer unit pressed against the photosensitive drum 1.
And a pressure roller 7 arranged at a distance. The developing means 4-1 (4-2, 4-3, 4-4) is arranged at a distance of, for example, about 50 μm to 200 μm from the photosensitive drum 1 and is capable of rotating in the same direction with respect to the photosensitive drum 1. 1 (8-2, 8-3, 8-4) and a liquid storage unit serving as a liquid developer storage unit provided to store a liquid developer therein and to immerse a part of the developing roller in the liquid developer. 9
-1 (9-2, 9-3, 9-4). FIG. 2 is a partially cutaway side view of the vicinity of the Y color developing means of the first embodiment, and FIG. 3 is a partially cutaway front view of the Y color developing means of the first embodiment. The diameter of the developing roller 8-1 at both ends is larger than that of the developing roller 8-1, is arranged coaxially with the developing roller 8-1, can rotate integrally with the developing roller 8-1, and A contact roller 13-1 is provided which is pressed against a non-image area where the liquid developer is not supplied. Further, a tank (liquid developer storage unit) for storing the liquid developer supplied to the developing roller 8-1 and a tank (carrier solvent storage unit) for storing the carrier solvent supplied to the contact roller 13-1 are provided. The liquid storage unit 9-1 is provided so that a part of the developing roller 8-1 is immersed in the liquid developer, and a part of the contact roller 13-1 is immersed in the carrier solvent. Here, the liquid storage unit 9-1 is a partition plate 1
4 separates the liquid developer from the carrier solvent. As means for supplying the liquid developer and the carrier solvent to the liquid storage unit 9-1, pumps, pipes, storage units for the respective liquids, sensors, etc., which are not shown, are provided. Also,
M, C, and Bk colors are provided with the same developing means as the Y color described above. Solvent removal means 5-1 (5-
2, 5-3, 5-4) are squeezed rollers 10-1 (10-2, 10-3, 10-4) which are arranged separately from the photosensitive drum 1 and are rotatable in the opposite direction to the photosensitive drum 1. )
And a surplus liquid developer storage unit 11-1 (11-2, 11-3, 11-4) for storing the liquid developer removed from the photosensitive drum 1 by the transfer of the squeeze roller. Squeeze roller 10-1 (10-2, 10-3,
10-4), the contact rollers 15-1 (15-2, 15-) provided coaxially and rotatable integrally at both ends.
3, 15-4) are provided so as to be in pressure contact with the photosensitive drum 1.

The photosensitive drum 1, the intermediate transfer roller 6, the pressure roller 7, and the developing roller 8-1 (8-2, 8-3, 8-
4), squeeze roller 10-1 (10-2, 10-
3, 10-4) driving sources (not shown) are provided for each configuration. The paper 12 is inserted between the intermediate transfer roller 6 and the pressure roller 7 and is conveyed in a certain direction.

The operation of the first embodiment having such a configuration will be described. Note that the photosensitive drum 1 is assumed to be stopped while a print operation command is not input from the user. The rotation direction of the photosensitive drum 1 is constant, for example, clockwise. First, the Y-color scorotron charger 2-
1, the position where the electrostatic latent image is formed on the photosensitive drum 1 is uniformly charged, and the charged area receives the image-modulated exposure light from the laser exposure source 3-1. An electrostatic latent image is formed on the image. Next, a liquid developer is supplied to the formed electrostatic latent image by the developing roller 8-1 and developed to develop the electrostatic latent image into a visible image. The squeeze roller 10-1 operates to remove excess liquid developer on the surface of the photosensitive drum 1. This Y color developing process is the first
Development. Subsequent to the first development of Y color development,
The position where the electrostatic latent image is formed on the photosensitive drum 1 is uniformly charged by the M-color scorotron charger 2-2, and the charged area receives the image-modulated exposure light from the laser exposure source 3-2. Then, an electrostatic latent image is formed on the exposed portion that has been exposed. A liquid developer is supplied to the formed electrostatic latent image by a developing roller 8-2, and the electrostatic latent image is developed and visualized. The squeeze roller 10-2 operates to remove excess liquid developer on the photosensitive drum 1. This M color development step is referred to as second development. On the surface of the photosensitive drum 1 after the completion of the second development, toner images of two colors of Y and M are formed. Subsequent to the second development of the M color, the position where the electrostatic latent image is formed on the photosensitive drum 1 is uniformly charged by the scorotron charger 2-3, and the laser exposure source 3 image-modulated in the charged area. -3 exposure light,
An electrostatic latent image is formed on the exposed portion that has received this exposure. A liquid developer is supplied to the formed electrostatic latent image by a developing roller 8-3, and the electrostatic latent image is developed into a visible image. The squeeze roller 10-3 operates to remove excess liquid developer on the photosensitive drum 1. This C color development step is referred to as a third development. After completion of the third development, toner images of three colors of Y, M, and C are formed on the surface of the photosensitive drum 1.

Subsequent to the third development of the C color, the position where the electrostatic latent image is formed on the photosensitive drum 1 is uniformly charged by the scorotron charger 2-4, and a laser image-modulated in the charged area is provided. Exposure light from the exposure source 3-4 is received, and an electrostatic latent image is formed on the exposed portion that has been exposed. A liquid developer is supplied to the formed electrostatic latent image by a developing roller 10-4, and is developed to visualize the electrostatic latent image. The squeeze roller 10-4 operates to remove excess liquid developer on the photosensitive drum 1. This Bk color development step is referred to as fourth development. After the fourth development, a full-color toner image of four colors of Y, M, C, and Bk is formed on the surface of the photosensitive drum 1. The first to fourth developments are performed while the photosensitive drum 1 makes one rotation.

Next, after a full-color toner image is formed on the surface of the photosensitive drum 1, the visible image is transferred to the intermediate transfer roller 6, which is heated and held at a constant temperature (higher than the surface temperature of the photosensitive drum 1). . The visible image transferred to the intermediate transfer roller 6 is transferred to the paper 12 inserted between the intermediate transfer roller 6 and the pressure roller 7 under the pressure of the pressure roller 7. . The transfer of the visible image from the intermediate transfer roller 6 to the sheet 12 is transfer by pressure or transfer by heat.

The paper 12 on which the visible image has been transferred and fixed is transported out of the electrophotographic apparatus by transport means (not shown).

Note that the contact rollers 13-1 (13-2, 1
3-3 and 13-4) are pressed against the photosensitive drum 1 by a pressing mechanism (not shown), and the photosensitive drum 1 and the developing roller 8 are pressed.
-1. When the developing roller 8-1 is rotated, the liquid developer is scooped up from the liquid storage unit 9-1 by the frictional force and the surface tension on the surface of the developing roller 8-1, and is conveyed to the surface of the photosensitive drum 1 at the same time. The carrier solvent is scooped up from the liquid storage unit 9-1 by the frictional force and the surface tension on the surface of the contact roller 13-1, and is conveyed to the surface of the photosensitive drum 1.

After the liquid developer is supplied to the surface of the photosensitive drum 1 by the developing roller 8-1, the excess liquid developer is supplied to the photosensitive drum 1 by the squeeze roller 10-1.
Remove from surface. Specifically, the squeeze roller 10
The liquid developer on the surface of the photosensitive drum 1 adheres to the surface of the squeeze roller 10-1 and is collected from the surface of the photosensitive drum 1 by rotating the liquid developer -1 in reverse to the rotation of the photosensitive drum 1. The liquid developer collected by the squeeze roller 10-1 is provided at a distance from the squeeze roller 10-1, and substantially removes the liquid developer on the surface of the squeeze roller 10-1 from the surface of the squeeze roller 10-1. It is removed by a scraping blade 16. The removed liquid developer travels along the side surface of the blade 16 and is stored in a surplus liquid developer storage unit 11-1 that stores the liquid developer removed by the blade 16. In the first embodiment as described above, the liquid developer supplied to the photosensitive drum 1 by the partition plate 14 is, for example, a contact portion between the contact roller 13-1 and the photosensitive drum 1, or a contact roller 13-. Since the carrier does not enter the supporting portion that supports the rotating shaft 1 and only the carrier solvent is present in the contact portion or the supporting portion, the contact portion or the supporting portion between the photosensitive drum and the guide roller is different from the related art. It is possible to prevent surface deterioration due to polishing by toner particles in the fixed liquid developer, and as a result, it is possible to eliminate uneven rotation and perform high-quality printing. In addition, since the carrier solvent intervenes in the contact portion, the carrier solvent becomes a lubricant and the friction coefficient is reduced, so that the life at the contact portion between the photosensitive drum 1 and the contact roller 13-1 is increased. Can be. Next, the configuration of a mobile phone according to a second embodiment of the wet electrophotographic apparatus of the present invention will be described with reference to FIG. In the following embodiments,
The same components are denoted by the same reference numerals, and redundant description will be omitted. A feature of the second embodiment is that the carrier solvent is positively supplied to a contact portion between the photosensitive drum 1 and, for example, the contact roller 13-1 by a method other than the supply by the rotation of the contact roller 13. FIG. 4 is a configuration diagram of the vicinity of the developing roller according to the second embodiment, and a carrier solvent suction unit 17 that sucks the carrier solvent into a tank in which the carrier solvent is stored.
Is provided at one end, and the sucked carrier solvent is
Solvent supply section 1 provided at the other end with a carrier solvent discharge section 18 for supplying a contact portion between the carrier solvent and contact roller 13-1
9 is provided near the contact roller 13-1. The carrier solvent supply unit 19, which is a means for sucking up the carrier solvent and supplying it between the photosensitive drum 1 and the contact roller 13, is a device such as a pump capable of supplying and discharging a fluid. While the photosensitive drum 1 is rotating, for example, a pump is operated to suck the carrier solvent from the carrier solvent suction unit 17, and the sucked carrier solvent is contacted with the contact roller 13-1 on the right side in the figure.
Is supplied to the contact portion (the liquid pool) from the outside surface of the. In the above-described second embodiment, the liquid developer supplied to the photosensitive drum 1 by the partition plate 14 is, for example, a contact portion between the contact roller 13-1 and the photosensitive drum 1, or a contact roller 13-. Since the carrier does not enter the supporting portion that supports the rotating shaft 1 and only the carrier solvent is present in the contact portion or the supporting portion, the contact portion or the supporting portion between the photosensitive drum and the guide roller is different from the related art. It is possible to prevent surface deterioration due to polishing by toner particles in the fixed liquid developer, and as a result, it is possible to eliminate uneven rotation and perform high-quality printing. In addition, since the carrier solvent intervenes in the contact portion, the carrier solvent becomes a lubricant and the friction coefficient is reduced, so that the life at the contact portion between the photosensitive drum 1 and the contact roller 13-1 is increased. Can be. In addition, by always supplying the carrier solvent between the photosensitive drum 1 and the contact roller 13, the possibility of toner particles being mixed therebetween is further reduced, and the contact state between the photosensitive drum 1 and the contact roller 13-1 is reduced. , And high image quality and long life can be achieved. Further, if the liquid developer is not always present between the developing roller 8-1 and the photosensitive drum 1, no pressure is generated between the photosensitive drum 1 and the developing roller 8-1, and the surface of the photosensitive drum 1 is not generated. The ability to remove excess liquid developer from
As a result, the solvent film thickness of the photosensitive drum 1 is increased by the excess liquid developer, and color mixture occurs when developing a different color at a later stage, and the image quality may be deteriorated.
When the carrier solvent that has passed between the photosensitive drum 1 and the photosensitive drum 1 flows between the developing roller 8-1 and the photosensitive drum 1, the liquid developer is transferred to the photosensitive drum 1 and the developing roller 8 by any chance.
A stable operation can be obtained and a high image can be output even when the value is insufficient between -1. Further, since the carrier solvent is supplied from the contact roller 13-1 toward the developing roller 8-1, even if the liquid developer and the carrier solvent supplied to the contact roller 13-1 are mixed, the liquid developer is supplied. Does not reach the contact roller 13-1, and a stable output with high image quality can be obtained. The supply amount of the carrier solvent to the contact portion between the contact roller 13-1 and the photosensitive drum 1 is smaller than that of the liquid developer stored in the liquid storage unit 9-1. However, it is assumed that this does not affect the toner density required for development. Next, the configuration of a third embodiment of the wet electrophotographic apparatus of the present invention will be described with reference to FIG. The feature of the third embodiment is that, as shown in the configuration diagram near the squeeze roller of the third embodiment in FIG. 5, for example, the liquid is stored in a tank of the surplus liquid developer storage unit 11-1 where the liquid developer is stored. Squeeze roller 10 serving as a developer removing roller
-1 is disposed, and a contact roller 15-1 is disposed in a tank (carrier solvent storage section) in which the carrier solvent is stored, and the partition plate 20 is provided so that the liquid developer and the carrier solvent are not mixed.
Is provided in the surplus liquid developer storage unit 11-1. It should be noted that the M, C, and Bk colors also have the above-described Y color.
Surplus liquid developer storage units 11-2, 11-3 similar to the colors,
11-4 are provided. With such a configuration,
The surplus liquid developer removed from the surface of the photosensitive drum 1 by the squeeze roller 10-1 is not mixed in the surplus liquid developer storage unit 11-1 by the partition plate 20 in the tank containing only the carrier solvent. It is not supplied to the contact portion between the contact roller 15-1 and the photosensitive drum 1 by the roller 15-1, and only the carrier solvent can be present in this contact portion. The third as described above
In the embodiment, since the liquid developer and the carrier solvent are separated by the partition plate 20, the liquid developer supplied to the photosensitive drum 1 is, for example, a contact portion between the contact roller 15-1 and the photosensitive drum 1. Alternatively, since the carrier does not enter the supporting portion that supports the rotating shaft of the contact roller 15-1, and only the carrier solvent is present in the contact portion or the supporting portion, the contact between the photosensitive drum and the guide roller as in the related art occurs. It is possible to prevent surface deterioration due to polishing by toner particles in a liquid developer fixed at a portion or a support portion, and as a result, it is possible to eliminate rotational unevenness and perform high-quality printing. Further, since the carrier solvent intervenes in the contact portion, the carrier solvent serves as a lubricant to reduce the friction coefficient.
The life at the contact portion with 5-1 can be extended. Next, the structure of a fourth embodiment of the wet electrophotographic apparatus of the present invention will be described with reference to FIG. The feature of the fourth embodiment is that the carrier solvent is positively supplied to the contact portion between the photosensitive drum 1 and, for example, the contact roller 15-1 by a method other than the method of supplying the carrier solvent by rotating the contact roller 13. That is. FIG. 6 is a configuration diagram in the vicinity of the squeeze roller 10-1 of the fourth embodiment. A carrier solvent suction unit 21 that sucks the carrier solvent into a tank in which the carrier solvent is stored is provided at one end. At the other end, a carrier solvent supply unit 23 provided at the other end with a carrier solvent discharge unit 22 for supplying a contact portion between the photosensitive drum 1 and the contact roller 15-1 is provided near the contact roller 15-1. The carrier solvent supply unit 23 which sucks up the carrier solvent and supplies it to the contact portion is a device such as a pump which can supply and discharge a fluid. While the photosensitive drum 1 is rotating, for example, a pump is operated to suck the carrier solvent from the carrier solvent suction unit 21 and the sucked carrier solvent is removed from the outside surface of the contact roller 15-1 on the right side in the drawing. (Liquid pool). In the fourth embodiment described above, since the liquid developer and the carrier solvent are separated by the partition plate 20, the liquid developer supplied to the photosensitive drum 1 is, for example, contact roller 1
5-1 Contact portion of photosensitive drum 1 or contact roller 1
Since the carrier does not enter the support for supporting the rotary shaft of 5-1 and only the carrier solvent exists in the contact or the support, the contact or the support between the photosensitive drum and the guide roller as in the prior art is used. It is possible to prevent surface deterioration due to polishing by toner particles in the liquid developer fixed in the portion, and as a result, it is possible to eliminate uneven rotation and perform high-quality printing. In addition, since the carrier solvent intervenes in the contact portion, the carrier solvent becomes a lubricant and the friction coefficient is reduced, so that the life at the contact portion between the photosensitive drum 1 and the contact roller 15-1 is increased. Can be. In addition, by always supplying the carrier solvent to the contact portion, the possibility that toner particles are mixed into the contact portion is further reduced, the contact state between the photosensitive drum 1 and the contact roller 15-1 is kept good, and Image quality and long life can be achieved. Also, squeeze roller 1
If the liquid developer is not always present between the photosensitive drum 1 and the photosensitive drum 1, the photosensitive drum 1 and the squeeze roller 10-
No pressure is generated between the photosensitive drum 1 and the surface of the photosensitive drum 1, and the ability to remove excess liquid developer from the surface of the photosensitive drum 1 is reduced. As a result, the excess liquid developer increases the solvent film thickness of the photosensitive drum 1. When developing different colors, color mixing may occur and image quality may deteriorate. However, the carrier solvent is applied between the contact roller 15-1 and the photosensitive drum 1 by the squeeze roller 10-.
Liquid developer flows between the photosensitive drum 1 and the photosensitive drum 1 to cause the liquid developer to flow between the photosensitive drum 1 and the squeeze roller 10-1.
Thus, a stable operation can be obtained and a high image can be output even in the case where there is a shortage between the two. In addition, the carrier solvent,
In order to supply the liquid developer from the contact roller 15-1 toward the squeeze roller 10-1, the liquid developer and the contact roller 15-1
The liquid developer does not reach the contact roller 15-1, even when the carrier solvent supplied to the
A high-quality stable output can be obtained. The present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. For example, the transfer of a visible image from the photosensitive drum to the intermediate transfer roller can be performed by an electric field,
Any of transfer by pressure (and heat) may be used. Further, by heating the pressure roller, it is possible to efficiently fix the visible image on the sheet. Further, the visible image on the surface of the photosensitive drum can be directly transferred and fixed to the sheet by using only the pressing roller without using the intermediate transfer roller. Further, the supply of the carrier solvent to the contact roller other than the method of supplying the carrier solvent to the photosensitive drum by immersing the contact roller in the carrier solvent in the tank in which the carrier solvent is stored is substantially performed in the direction in which the contact roller rotates. Even if it is not supplied by a pump etc. from the orthogonal direction,
It can also be supplied by a pump or the like from the same plane where the contact roller rotates.

Further, by reducing the supply of the liquid developer to a portion of the surface of the photosensitive drum where the liquid developer does not need to be adhered (for example, a contact portion between the photosensitive drum and the contact roller), the photosensitive required for offset transfer is reduced. The burden on the drying process of the drum surface can also be reduced.

Also, the liquid developer supplied to the developing roller and the carrier solvent supplied to the contact roller can supply each liquid to the developing roller and the contact roller even if they are not stored in the liquid storage unit. If possible, the liquid developer can be supplied directly near the gap between the photosensitive drum and the developing roller, and the carrier solvent can be directly supplied near the contact portion between the contact roller and the photosensitive drum. In this case,
A container that receives the liquid developer dripping from the developing roller near the developing roller and a container that receives the carrier solvent dripping from the contact roller can be disposed near the contact roller.

[0023]

As described above, according to the present invention, a high quality image can be obtained without a toner particle interposed between the photosensitive drum and the contact roller, and the life can be extended. .

[Brief description of the drawings]

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

FIG. 2 is a partially cutaway side view of the vicinity of a developing unit in the first embodiment of the wet electrophotographic apparatus of the present invention.

FIG. 3 is a partially cutaway front view in the vicinity of a developing roller of the first embodiment of the wet electrophotographic apparatus of the present invention.

FIG. 4 is a partially cutaway front view near a developing roller of a second embodiment of the wet electrophotographic apparatus of the present invention.

FIG. 5 is a partially cutaway front view near a squeeze roller of a third embodiment of the wet electrophotographic apparatus according to the present invention.

FIG. 6 is a partially cutaway front view near a squeeze roller of a third embodiment of the wet electrophotographic apparatus according to the present invention.

[Explanation of symbols]

1 Photosensitive drum 2-1, 2-2, 2-3, 2-4 Scorotron charger 3-1, 3-2, 3-3, 3-4 Laser exposure source 4-1, 4-2, 4-3 , 4-4 Developing means 5-1 5-2, 5-3, 5-4 Solvent removing means 6 Intermediate transfer roller 7 Pressure roller 8-1, 8-2, 8-3, 8-4 Developing roller 9 -1, 9-2, 9-3, 9-4 Liquid storage unit 10-1, 10-2, 10-3, 10-4 Squeeze roller 11-1, 11-2, 11-3, 11-4 Surplus Liquid developer storage unit 12 Paper 13-1, 13-2, 13-3, 13-4 Contact roller 14, 20 Partition plate 15-1, 15-2, 15-3, 15-4 Contact roller 16 Blade 17, 21 Carrier solvent suction section 18, 22 Carrier solvent discharge section 19, 23 Carrier solvent supply section

Claims (2)

[Claims] A latent image holding member rotatable in a fixed direction for holding an electrostatic latent image on a surface; a latent image forming means for forming an electrostatic latent image on the latent image holding member; A liquid developer storage unit for storing a liquid developer comprising a carrier solvent for visualizing the latent image and toner particles dispersed in the carrier solvent; and a liquid developer storage unit provided in non-contact with the latent image holding member. Developing means having a developing roller for supplying the liquid developer in the liquid developer storage section to the surface of the latent image holding member; and transferring a visible image visualized by the developing means onto an image carrier. A wet electrophotographic apparatus having a transfer unit, wherein the developing unit is further provided coaxially with the developing roller so as to be in contact with the latent image holding member, and a carrier solvent storage unit that stores only a carrier solvent. The carrier solvent of the carrier solvent storage unit And a contact roller to which the liquid is supplied. 2. A latent image holding member rotatable in a fixed direction for holding an electrostatic latent image on a surface thereof; a latent image forming means for forming an electrostatic latent image on the latent image holding member; A liquid developer storage unit for storing a liquid developer comprising a carrier solvent for visualizing the latent image and toner particles dispersed in the carrier solvent; and a liquid developer storage unit provided in non-contact with the latent image holding member. A developing roller for supplying the liquid developer in the liquid developer storage section to the surface of the latent image holding member, and a liquid developer for removing a part of the liquid developer supplied to the surface of the latent image holding member by the developing roller A developing unit having a removing roller, and a transfer unit for transferring a visible image visualized by the developing unit onto an image carrier, wherein the developing unit further comprises: Carrier solvent storage unit that stores only carrier solvent And a contact roller provided coaxially with the liquid developer removing roller so as to be in contact with the latent image holding member and supplied with a carrier solvent in the carrier solvent storage unit. .