JPH07239614A - Liquid developing device of electrostatic latent image - Google Patents

Abstract

PURPOSE:To uniformly supply a small amt. of a liquid developer having a high concn. and high viscosity to the latent image surface of an image base by providing the above device with a coating applying means for applying the liquid developer formed under specific conditions on the surface of the developer base and providing the device with a developing means for supplying the liquid developer to the surface of the image base via the develop base. CONSTITUTION:The liquid developer which is prepd. by dispersing toner of a high concn. into an insulating liquid and has a viscosity of 100 to 10000mPa.s is applied on a developing belt 510 and the layer thickness of the liquid developer 508 applied thereon is regulated to have a thickness 5 to 40Xm by a layer forming blade 504. A developer supplying roller 506 is rotated in a direction opposite to the rotating direction of the developing belt 510 to transport the liquid developer 508 to the surface of the developing belt 510. The developing belt 510 is rotated in the direction opposite to the rotating direction of a photoreceptor 10 by driving rollers 512a to 512c, the liquid developer 508 applied by the developer supplying roller 506 is supplied to the surface of the photoreceptor 10. As a result, the liquid developer having a high concn. and high viscosity is uniformly supplied.

Description

Detailed Description of the Invention

[0001]

The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a liquid developing device for an electrostatic latent image that visualizes an electrostatic latent image formed by a method such as ionography using a liquid developer.

[0002]

2. Description of the Related Art Conventionally, in an electrostatic latent image liquid developing apparatus for developing an electrostatic latent image formed on an image support with toner, which is a charged image-forming particle, the latent image on the image support is used. When supplying the liquid developer to the surface, a method of forming unevenness on the surface of the developing roller, which is the developer support, and holding the liquid developer in the recess to supply it to the image support, a sponge roller to the developer support. By using the sponge roller to press the image support, the liquid developer absorbed by the sponge roller is supplied to the image support, or the image support is immersed in a developer tank in which the liquid developer is stored. Therefore, a method of directly supplying the liquid developer to the image support without using the developer support is used.

[0003]

However, in the conventional electrostatic recording apparatus, IsoparG which is generally an organic solvent is used.
(Registered trademark: manufactured by Exxon), a low-viscosity liquid developer in which a toner is mixed at a ratio of about 1 to 2% is used. However, in order to suppress the generation of solvent vapor and realize a safer and more compact liquid developing device, it is preferable to use a liquid developer having a higher concentration than the liquid developer used in the conventional device. No such device has been found in the past.
Therefore, a high-concentration and high-viscosity liquid developer (a high-viscosity liquid developer of 100 to 10000 mPa · s in which toner is dispersed in an insulating liquid at a high concentration) is used because the supply amount to the image support is small. In that case, it is not clear what method is suitable for supplying the liquid developer to the latent image surface of the image support.

[0004]

[Object] The present invention has been made based on the above circumstances, and by controlling the layer thickness of a high-concentration and high-viscosity liquid developer coated on a developer support thinly and uniformly, An object of the present invention is to provide an electrostatic latent image liquid developing device capable of uniformly supplying a small amount of high-concentration and high-viscosity liquid developer to a latent image surface of an image support without adhering toner to a non-image portion. It is what

[0005]

In order to solve the above problems, a liquid developing apparatus for an electrostatic latent image according to the present invention comprises a developer support and a viscosity 1 in which toner is dispersed in an insulating liquid at a high concentration.
Liquid developer of 00 to 10,000 mPa · s is 5 to 40 μm.
a coating means for coating the surface of the developer support with a thickness of m, and a developing means for supplying the liquid developer to the surface of the image support through the developer support. It is a feature.

The coating means preferably comprises a layer-forming blade provided so as to come into contact with the developer support in the trail direction.

Further, the coating means may be provided with at least two rollers.

Further, the coating means may include a roller whose surface is covered with sponge.

Further, in the electrostatic latent image liquid developing apparatus of the present invention, a pre-wet liquid, which is a dielectric liquid having releasability and chemically inert, is applied onto the image support. It is preferable to have a means.

[0010]

In the liquid electrostatic latent image developing device of the present invention, the liquid developer having the above-described structure and having a high concentration of toner dispersed therein is developed into a thin layer to develop the liquid, so that the liquid amount is the same as that of the conventional low concentration liquid. It can be much less than the developer. When the viscosity of the liquid developer is 10,000 mPa · s or more, it becomes difficult to stir the insulating liquid and the toner, and a problem is how to make the liquid developer. Therefore, a liquid developer of 10,000 mPa · s or more becomes unrealistic in terms of cost and becomes unrealistic. On the other hand, 100m
If it is less than Pa · s, the toner density will be low and the dispersibility of the toner will be poor, so that the developer cannot be made into a thin layer for development. The layer thickness of the liquid developer needs to be thin when the toner concentration is high and thick when the toner concentration is low. In addition, the higher the viscosity, the thinner it needs to be. However, when the layer thickness of the liquid developer is thicker than 40 μm, excessive adhesion of toner occurs and image noise occurs. On the other hand, when the layer thickness is less than 5 μm, unevenness occurs when a solid black image is output.

Further, when a layer forming blade whose front end is in contact with the developer support in the trail direction is used as the coating means, the layer thickness of the high-viscosity liquid developer coated on the developer support is Since it can be thinly and uniformly regulated, a small amount of liquid developer can be uniformly supplied to the latent image surface of the image support.

When a liquid developer is applied to the surface of the developer support through at least two rollers as the coating means, a high-concentration and high-viscosity liquid developer is applied onto the developer support. Can be applied thinly and uniformly, so that a small amount of liquid developer can be uniformly supplied to the latent image surface of the image support.

Furthermore, when a roller having a predetermined thickness of sponge, porosity and pore diameter is used as the application means, a small amount of liquid developer held by the roller is thinly and unevenly distributed on the developer support. Therefore, a small amount of highly concentrated and highly viscous liquid developer can be uniformly supplied to the latent image surface of the image support by bringing the developer support into contact with the image support. .

When a pre-wetting means for applying a pre-wetting liquid, which is a dielectric liquid having releasability and chemically inert, is provided on the image support, a non-image of the image support is provided. It is possible to prevent the toner from adhering to the portion.

The viscosity of the pre-wet liquid is 0.5 to 5 m.
Pa · s, electric resistance of 10 ¹² Ωcm or more, boiling point of 100
When the surface tension is ˜250 ° C. and the surface tension is 21 dyn / cm or less, a pre-wetting liquid having releasability and good insulation can be obtained. The pre-wetting liquid is absorbed by paper or the like at the time of transfer, and thus needs to be evaporated at the time of fixing. For this reason, the viscosity is 0.
5 to 5 mPa · s is desirable. If the viscosity is 5 mPa · s or more, it becomes difficult to evaporate, and if it is 0.5 mPa · s or less, the volatility becomes high. If the boiling point is 100 ° C. or less, the amount of evaporation increases, which causes a problem in the method of storing the pre-wet liquid, the entire device must have a closed structure, and it is difficult to improve the working environment. On the other hand, when the boiling point is 250 ° C. or higher, the paper is curled at the time of fixing and cannot be used, and high energy for heating is required, resulting in high cost. When the electric resistance is 10 ¹² Ωcm or less, the insulating property is deteriorated and the prewetting liquid cannot be used. Therefore, it is desirable that the electric resistance value is as high as possible.
When the surface tension is 21 dyn / cm or more, the wettability becomes poor and the compatibility with the liquid developer becomes poor. Therefore, it is desirable that the surface tension be as low as possible.

In the electrostatic latent image liquid developing apparatus of the present invention, the insulating liquid has a viscosity of 0.5 to 1000 mPa · s, an electric resistance of 10 ¹² Ωcm or more, and a surface tension of 21 dyn / cm or less,
When a liquid developer having a boiling point of 100 ° C. or higher is used, a highly viscous liquid developer can be obtained. Since the liquid developer formed on the developer support is formed in a thin layer, the amount of the insulating liquid contained in the liquid developer layer is extremely small, so that it is supplied to the latent image surface of the image support. The insulating liquid contained in the liquid developer is also extremely small. Therefore, the amount of insulating liquid that is absorbed by the paper during transfer is extremely small, and the viscosity is 1000 mP.
If it is a · s or less, the problem of the insulating liquid adhering to the paper or the like does not occur. However, if the viscosity is 0.5 mPa · s or less, the volatility becomes high, so that it is not suitable because it is subject to legal regulation as a dangerous substance. When the boiling point of the insulating liquid is 100 ° C. or less, the amount of evaporation is large, so that there is a problem in the method of storing the developer, the entire device must have a closed structure, and it is difficult to improve the working environment. . Electrical resistance is 1
If it is less than 0 ¹² Ωcm, the insulating property will be deteriorated, and the toner will have a problem of conductivity, and cannot be used as a developer.
Therefore, it is desirable that the electric resistance be as high as possible.
When the surface tension is 21 dyn / cm or more, the wettability becomes poor and the compatibility with the pre-wet liquid becomes poor. Therefore, it is desirable that the surface tension be as low as possible.

When the liquid developer contains a toner having an average particle diameter of 0.1 to 5 μm in a concentration of 5 to 40%, a liquid developer in which the toner is dispersed in an insulating liquid at a high concentration can be obtained. it can. In addition, the resolution is improved in almost inverse proportion to the particle size of the toner. Usually, the toner is present as a mass of about 5 to 10 particles on the printed paper, and therefore, when the average particle diameter of the toner is 5 μm or more, the resolution becomes poor. On the other hand, the average particle size of the toner is 0.
When the thickness is 1 μm or less, the physical adhesive strength increases, and it becomes difficult to peel off the toner during transfer.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an electrostatic latent image liquid developing device according to a first embodiment of the present invention, and FIG. 2 is a schematic perspective view of a pre-wetting device used in the electrostatic latent image liquid developing device shown in FIG. 3, FIG. 3 is a diagram for explaining the operation of the electrostatic latent image liquid developing device shown in FIG. 1, FIG. 4 is a diagram for explaining the operation of the pre-wetting device shown in FIG. 2, and FIG. 5 is a pre-wetting liquid. FIG. 14 is a diagram showing the flow of the pre-wet liquid when the supply member is brought into contact with the photoconductor, and FIG. 14 is a schematic diagram of a developing device used in the liquid developing device for the electrostatic latent image shown in FIG.

The electrostatic latent image liquid developing apparatus 1 according to the first embodiment of the present invention is, as shown in FIG. A pre-wetting device 20, a charging device 30 that charges the photoconductor 10, and an exposure device 40 that exposes an image on the photoconductor 10.
And a developing device 50 that visualizes the electrostatic latent image by supplying toner to the portion of the photoconductor 10 on which the electrostatic latent image is formed.
A transfer device 60 for transferring and fixing the toner on the photoconductor 10 to a predetermined paper, and a cleaning device 70 for removing the toner remaining on the photoconductor 10.

Charging device 30, exposure device 40, transfer device 6
0, the cleaning device 70, and the static eliminator 80, the conventional technique used in the conventional electrophotographic printer can be used in most cases. Therefore, in the present embodiment, the description of each of the above devices will be omitted, and the pre-wetting device 20 and the developing device 50, which are the main parts of the present invention, will be described.

As shown in FIG. 2, the pre-wetting device 20 includes a plate-shaped pre-wetting liquid supplying member 202 having a length substantially the same as the image width drawn on the photosensitive member 10, and a pre-wetting liquid supplying member 202. A case 204 for storing, a tank 206 for storing the pre-wet liquid 220, and a tank 20.
6, a pump 208 for pumping up the pre-wet liquid 220 stored therein, tubes 210a and 210b, and a displacement device 212.

As the pre-wet liquid supply member 202, a continuous porous body having a three-dimensional network structure in which pores are continuous, for example, Beluita (registered trademark: Kanebo Co., Ltd.) is used. The bell eater is pre-wet liquid 2 for the volume of the pores.
20 can be held, and when the pre-wet liquid 220 exceeding the pore volume is supplied, the pre-wet liquid 220 can be uniformly discharged in the direction perpendicular to the flow direction of the pre-wet liquid 220. As shown in FIG. 4, on the surface of the case 204 facing the photoconductor 10, the bottom surface of the pre-wet liquid supply member 202 is provided on the photoconductor 10.
The opening portion 204a is provided so that it can be brought into contact with the. The tube 210 a conveys the pre-wet liquid 220 pumped up by the pump 208 to the supply side 202 a of the pre-wet liquid supply member 202. The supply side 202a of the pre-wet liquid supply member 202 and the case 20
4 is formed with a space portion 204b, and after the pre-wetting liquid 220 is stored in this space portion 204b,
It is supplied from the supply side 202a. The tube 210b is
The pre-wet liquid 220 discharged from the discharge side 202b of the pre-wet liquid supply member 202 is conveyed to the tank 206. When a signal from the outside is not input, the displacement device 212 holds the pre-wet liquid supply member 202 at a position away from the photoconductor 10, as shown in FIG.
When a signal from the outside is input, as shown in FIG. 4B, the pre-wet liquid supply member 202 is connected to the photosensitive member 1.
Contact 0.

As shown in FIG. 14, the developing device 50 has a tank 502 for storing a high-concentration and high-viscosity liquid developer 508, which will be described later, and a lower portion soaked in the liquid developer 508 stored in the tank 502. The developer supply roller 506 provided, the developing belt 510 which is a developer support disposed above the developer supply roller 506, and the developing belt 5.
Drive roller 51 for rotating and driving 10 and holding a part of the developing belt 510 in contact with the photoconductor 10.
2a, 512b, 512c and the front end portion of the developing belt 51
0 and a layer forming blade 504 having a width substantially the same as that of the developing belt 510 provided so as to abut in the trail direction;
Although not shown, a scraping unit such as a blade or a roller for removing the liquid developer 508 attached to the developing belt 510 after development is provided.

The developer supply roller 506 is the developing belt 5
The liquid developer 508 is conveyed to the surface of the developing belt 510 by rotating in the direction opposite to the rotating direction of 10. The developer supply roller 506 is used to supply the liquid developer 508 to the developing belt 510, as described later, in the present embodiment, since the liquid developer 508 in which toner is dispersed in a high concentration is used, a small amount is used. This is because it is necessary to apply the above developer to the surface of the developing belt 510 evenly.

The developing belt 510 includes a driving roller 512.
The liquid developer 5 applied to the surface of the photoconductor 10 by the developer supply roller 506 by being rotated in the direction opposite to the rotation direction of the photoconductor 10 by a, 512b, 512c.
08 is supplied. The developing belt 510 includes a metal belt such as a seamless nickel belt, a polyimide film belt, a resin belt such as a PET film belt,
A flexible belt-shaped member such as a rubber belt is used. Thereby, when the tension of the developing belt 510 is adjusted to disperse the contact pressure when the liquid developer layer formed on the developing belt 510 and the pre-wet liquid layer formed on the photoconductor 10 are dispersed, There is a gap between the photoconductor 10 and the developing belt 510 via the liquid developer layer and the pre-wet liquid layer. Therefore, the liquid developer layer formed on the developing belt 510 and the pre-wet liquid layer formed on the photoconductor 10 are contacted while maintaining a two-layer state in which the layers can be distinguished from each other, and It can be separated inside the pre-wet liquid layer.

The developing belt 510 must be capable of applying an electric developing bias. Therefore, when a resin belt or a rubber belt is used, it is necessary to reduce the electric resistance value by conducting conductive processing on the surface of the belt or adding conductive fine particles to the material of the belt. When the belt itself is electrically conductive, the drive rollers 512a, 5a
A rubber roller having a low electric resistance value, to which conductive particles are added so that a developing bias can be applied, is used for 12b and 512c. When the belt surface is subjected to conductive processing, a conductor that comes into contact with the belt surface is provided and a bias voltage is applied to this conductor. In addition, perforations are provided at both ends of the developing belt 510, and the perforations are engaged with the sprockets provided at both ends of the driving roller 512a to rotationally drive the developing belt 510. As a result, the developing belt 510 can be stably driven.

The layer forming blade 504 is the developing belt 51.
0 regulates the layer thickness of the liquid developer 508 applied on the surface of the liquid developer.
The layer forming blade 504 has a tip 5 as shown in FIG.
It is desirable that the protrusion amount l of 04a be 10 to 100 μm from the contact position 504b between the layer forming blade 504 and the developing belt 510. As will be described later, in this embodiment, a high-viscosity liquid developer having a viscosity of 100 to 10,000 mPa · s was used. Therefore, when the protrusion amount l is less than 10 μm, the liquid developer 5 coated on the developing belt 510 is used.
The layer thickness of No. 08 cannot be regulated to be thin. On the other hand, when the protrusion amount l exceeds 100 μm, the liquid developer 508 swells and the liquid developer 508 applied on the developing belt 510.
It becomes impossible to uniformly regulate the layer thickness of.

The layer forming blade 504 is formed of rubber that does not swell into the insulating liquid used for the liquid developer. As will be described later, since silicone oil is used as the insulating liquid of the liquid developer 508 in this embodiment, the layer forming blade 504 is made of fluorosilicone rubber, fluorine rubber, urethane rubber, or the like that does not swell into silicone oil. To be

Developing belt 510 of layer forming blade 504
The pressing force applied to the layer forming blade 504 is 10 to 1 when the hardness of the rubber used for the layer forming blade 504 is 60 to 70 ° (JIS A).
It is desirable to be 000 g / cm. Since the high-viscosity liquid developer 508 is used in this embodiment, the pressing force is 10 g.
If it is smaller than / cm, the layer thickness of the liquid developer 508 applied on the developing belt 510 cannot be regulated to be small,
On the other hand, when the pressing force exceeds 1000 g / cm, the liquid developer 508 swells and it becomes impossible to uniformly regulate the layer thickness of the liquid developer 508 applied on the developing belt 510. In order to obtain the above pressing force, the present inventors have
As shown in FIG. 4, one end of the layer forming blade 504 is held by the holding plate 513, and a fulcrum 513 a is provided at the end of the holding plate 513 on the side where the layer forming blade 504 is held, and the other end of the holding plate 513. The end of the was pulled by a spring or the like.
Then, the strength of the spring was set so that the flexure t of the layer-forming blade 504 was about 1 mm when the free length h of the layer-forming blade 504 was 15 mm.

Next, the image forming material used in the first embodiment of the present invention will be described. The liquid developer 508 used in this embodiment is a toner that is a resin that serves as a binder such as epoxy, a charge control agent that gives a predetermined charge to the toner, a color pigment, a dispersant that uniformly disperses the toner, and a carrier liquid. Consists of. The toner composition is basically similar to that used in conventional liquid developers, but their formulation has been modified to be compatible with silicone oils for adjusting charging characteristics and dispersibility. The smaller the average particle size of the toner is, the better the resolution is. However, the smaller the particle size is, the larger the physical adhesive force is, and the more difficult it is to remove when transferring. Therefore, in this embodiment, the average particle diameter of the toner is adjusted so that the center is around 2 to 4 μm for the purpose of improving transferability.

The viscosity of the liquid developer depends on the carrier liquid used,
It depends on the resin, color pigment, charge control agent, etc. and their concentrations. In this example, the viscosity is 50 to 6000 m.
An experiment was conducted by changing the Pa · s and the toner concentration within the range of 5 to 40%.

As the carrier liquid, one having a low viscosity such as dimethylpolysiloxane oil having a high electric resistance or cyclic polydimethylsiloxane oil is used. Incidentally, the developing belt 510
Since the liquid developer layer formed on top is formed in a thin layer, the carrier liquid contained in the liquid developer layer is extremely small, so that the amount of carrier liquid in the liquid developer supplied to the latent image surface of the photoconductor 10 is small. The carrier liquid contained in is very small. Therefore, the carrier liquid absorbed in the paper or the like during transfer is extremely small, and if the viscosity is 1000 mPa · s or less, almost no carrier liquid remains after fixing. According to experiments conducted by the present inventors, the carrier liquid has a viscosity of 2.5 mPa · s, DC3 manufactured by Dow Corning Co., USA.
44 and a viscosity of 6.5 mPa · s, when the image output experiment was conducted using DC345 of Dow Corning Co., USA,
In each case, no carrier liquid remained on the paper after fixing. However, since the volatility is high, it is necessary to make the developing device have a closed structure. Furthermore, the carrier liquid has a viscosity of 2
Shin-Etsu Silicon KF-96-20 with 0 mPa · s
No carrier liquid remained on the paper after fixing was observed when the image output experiment was carried out using. Further, since the volatility is not so high, it is not necessary to make the developing device have a closed structure. DC344, DC345 and KF-96-
20 is generally used in cosmetics and has high safety such as toxicity. There are many kinds of carrier liquids such as KF9937 manufactured by Shin-Etsu Silicon Co., Ltd., and any one may be selected as long as the electric resistance, the evaporation property, the surface tension, the safety and the like are satisfied.

In an experiment conducted by the inventors, when the surface tension is large, the image may become unclear and toner lumps may adhere.
It has been found that when the value is n / cm or more, a problem in image quality easily occurs.

The electric resistance value is preferably 10 ¹⁴ Ωcm or more because of the problem of toner charging stability. At least 1
0 ¹² Ωcm or more is necessary. In the description of the present embodiment, in view of these experimental results, the DC3 is low in price and easily available.
An example using 45 is shown.

The pre-wetting liquid easily evaporates during fixing without disturbing the electrostatic latent image formed on the image support,
It is required that fogging and lumps of toner do not adhere. As an example, DC34 manufactured by Dow Corning, USA
4, DC200-0.65, -1.0, -2.0, KF96L-1, KF9937 manufactured by Shin-Etsu Silicon Co., and the like. Generally, it is preferable to select a highly evaporative silicone oil.

In an experiment conducted by the inventors, the liquid viscosity was 0.
The liquid was dried by development, transfer, and fixing without problems in the range of 5 to 3 mPa · s, but from 5 mPa · s to 6 mPa · s
-At about s, there was a tendency that time and temperature were required for drying the liquid at the time of fixing. If it is 10 mPa · s, the energy required for drying becomes too large, which is not general. Also,
If it is 0.5 mPa · s or less, the volatility increases, so
It is not appropriate because it is subject to legal regulations as dangerous goods. In addition, the boiling point is preferably 250 ° C. or lower because of the influence of heating the paper.

The surface tension is preferably as low as possible in order to eliminate the adhesive force between the developer and the image support, improve the releasability, prevent the image from becoming dirty, and improve the resolution of the image quality. According to experiments by the present inventors, 20 to 21 dyn / c
It is preferable to select one having a limit of about m and lower than this.

When the electric resistance is low, the latent image charge leaks and the image is blurred. Therefore, it is necessary to use the highest possible one. Experimentally, about 10 ¹⁴ Ωcm or more is desirable. A minimum of 10 ¹² Ωcm is required.

Next, the operation of the electrostatic latent image liquid developing apparatus according to the first embodiment of the present invention will be described. First, FIG.
As shown in (A), the surface of the photoreceptor 10 is charged by the charging device 30.
To charge. Generally, a corona discharger is used for the charging device 30. Next, the image is exposed on the charged photoreceptor 10. For example, the image is exposed by a laser scanner to form an electrostatic latent image on the surface of the photoconductor 10. Figure 3
As shown in (B), the portion of the laser scanner exposed to the light becomes conductive, so that the electric charge disappears, and the portion not exposed to the light remains as an electrostatic latent image which is an image of the electric charge.

Next, as shown in FIG. 3C, the above-mentioned pre-wetting liquid 220 is applied onto the photoconductor 10 by the pre-wetting device 20. The pre-wetting device 20 brings the bottom surface of the pre-wetting liquid supply member 202 into contact with the photoconductor 10 when a control signal from the outside is input. The pre-wet liquid 220 is constantly circulated inside the pre-wet liquid supply member 202 by the pump 208, and the pre-wet liquid 220 exceeding the volume of the pores of the bell eater, which is the pre-wet liquid supply member 202, is shown in FIG. As described above, it is discharged from the discharge side 202b of the pre-wet liquid supply member 202 and from the bottom surface of the pre-wet liquid supply member 202, and is evenly applied on the photoconductor 10 without damaging the photoconductor 10.

Next, the electrostatic latent image is visualized by the developing device 50. Liquid developer 508 stored in tank 502
Is supplied to the developing belt 510 by the developer supply roller 506. The layer thickness of the liquid developer 508 supplied to the developing belt 510 is uniformly regulated by the layer forming blade 504. The liquid developer layer thus formed on the developing belt 510 is brought close to the electrostatic latent image formed on the surface of the photoconductor 10 as shown in FIG. 3D, and is charged by electrostatic force. The formed toner is moved onto the photoconductor 10 to form a toner image. The liquid developer 508 stored in the tank 502 is agitated by the rotation of the developer supply roller 506.

Next, as shown in FIG. 3E, the toner image on the photoconductor 10 is transferred onto the predetermined paper 60 by the electrostatic force generated by the voltage applied to the transfer roller 602 of the transfer device 60.
Transfer to 4. Although not shown in FIG. 1, as shown in FIG. 3F, the toner transferred to the paper 604 is thermally melted by the fixing heater 704 provided in the fixing roller 702 of the fixing device. It is fixed on the paper 604.
On the other hand, the liquid developer 508 remaining on the photoconductor 10 is removed by the cleaning device 70. Incidentally, the photoconductor 1
0 is repeatedly used in the cycle from charging to static elimination again after static elimination is performed by a static eliminating device (not shown).

6 to 10 are views for explaining the developing process of one embodiment of the present invention in detail, FIG. 6 is a diagram for explaining the developing process as a whole, and FIG. 7 is an approaching process. FIG. 8, FIG. 8 is a view showing a state of a toner movement process, FIG. 9 is a view showing a separation process of a non-image portion, and FIG. 10 is a view showing a separation process of an image portion. Unlike the conventional developing process, in the developing process of this embodiment, as shown in FIG. 6, a developing belt approaches a photoconductor and a liquid developer approaches a photoconductor surface, and a liquid developer layer is formed. A toner moving process in which the toner moves due to soft contact with the pre-wet liquid layer, and a separation process in which the developing belt separates from the photoconductor and is separated into toner adhering to the developing belt and toner adhering to the photoconductor. It is considered to consist of three processes.

In the approaching process, the developing belt 510 is made of a flexible member as shown in FIG.
A small gap, that is, a space d is formed between the developing belt 510 and the photoconductor 10, and the high-viscosity liquid developer including the carrier liquid and the toner is soft-contacted with the pre-wet liquid. As a result, the pre-wet liquid having a low viscosity is slightly pushed back and forth, and a liquid pool of the pre-wet liquid is generated.

In the toner moving process, as shown in FIG. 8, in the image portion, the toner passes through the pre-wet liquid layer mainly by the Coulomb force due to the electric field formed between the charges on the photoconductor 10 and the developing belt 510. And move to the latent image surface. On the other hand, the toner in the non-image area is basically the photosensitive member 10.
Since the surface of the liquid developer and the liquid developer layer are separated by the pre-wet liquid layer, unnecessary toner does not adhere to the surface of the photoconductor 10.

In the separation process, in the non-image part, as shown in FIG.
Basically, the liquid developer remains on the developing belt 510 as shown in FIG. At the interface between the pre-wet liquid layer and the liquid developer layer, when the two layers are separated, a part of the pre-wet liquid layer having a low viscosity is transferred to the liquid developer layer and separated. Therefore, the separation point of the two layers is considered to be inside the pre-wet liquid layer. On the other hand, in the image area, as shown in FIG. 10, the toner that has moved to the surface of the photoconductor 10 displaces the pre-wet liquid layer, so that the pre-wet liquid layer is located on the toner layer and is separated in that layer. On the developing belt 510, a part of the carrier liquid and a part of the pre-wetting liquid remaining after the toner moves form a layer. The pre-wetting liquid remaining on the photoconductor 10 facilitates the movement of the toner due to the electrostatic force in the subsequent transfer process.

FIG. 11 is a diagram for explaining the significance of thinning the liquid developer. If the liquid developer layer applied on the developing belt 510 is too thick, the liquid developer 508
Since the viscosity of the toner is high, a group of toners that try to move from the developing belt 510 to the surface of the photoconductor 10 by the electrostatic force forms a cluster without cutting off the adhesive force to the toner located around it, and To move to the surface,
Toner excessively adheres, causing image noise. In order to suppress the generation of these clusters, it is necessary to control the thickness of the liquid developer layer to a minimum value at which development can be sufficiently performed.

FIG. 12 is a diagram showing a state in which the developing roller, which is the developing support, is in hard contact with the photosensitive member, and FIG. 13 is a diagram for explaining the soft contact of this embodiment. As described above, the function of the pre-wet liquid layer for image formation is important in the developing process of this embodiment. Therefore, an important requirement in the developing process is to maintain the two-layer state of the pre-wet liquid layer and the liquid developer layer. As shown in FIG. 12, when the developing roller and the photoconductor are in hard contact, the two-layer state cannot be maintained. In this embodiment, as shown in FIG. 13, by using the developing belt 510 composed of a flexible member as the developer support, the tension of the developing belt 510 is adjusted and the developing belt 510 is adjusted. When the contact pressure at the time of contact between the formed liquid developer layer and the pre-wet liquid layer formed on the photoconductor 10 is dispersed, the liquid developer layer and the pre-wet liquid layer are used to develop the photoconductor 10 and the photoconductor 10. A minute gap, that is, a space d is formed between the belt 510 and the belt 510. Therefore, in the developing step, the liquid developer layer and the pre-wet liquid layer can be brought into contact with each other while maintaining the two-layer state.

Next, optimization of the layer thickness of the liquid developer layer, the layer thickness of the pre-wet liquid layer and the development gap, that is, the gap will be described. The layer thickness of the liquid developer layer is particularly 5 when the viscosity of the liquid developer is 50 to 100 mPa · s or more.
For those of 00 mPa · s or more, it is necessary to reduce the thickness. Ideally, it should be slightly thicker than the layer thickness that satisfies the toner development amount (that is, the concentration when a large area is painted black) required at the time of development. This is because when a high-viscosity liquid developer is used, electrostatically selected toner moves onto the photoconductor along with the excess toner due to the viscosity of the liquid during development, causing abnormal toner adhesion. This is because the image is smeared and the image is stained. According to an experiment conducted by the inventors, the liquid developer having a high toner concentration is 5
Good images were obtained with a layer thickness of about 40 μm for those having a low toner concentration from μm. Also, the toner density is 20 to 30%.
When the above liquid developer is used, the layer thickness of the liquid developer is 8 to 2
Good image quality was obtained at about 0 μm.

The layer thickness of the pre-wet liquid layer has an optimum value depending on the viscosity and surface tension of the selected pre-wet liquid. If it is too thin, the high-viscosity liquid developer irregularly adheres to the photoconductor to cause image contamination. As the amount of pre-wetting liquid is increased, image stains are improved,
The optimum value is confirmed. When the amount is further increased, the charge of the latent image flows, the sharpness and the resolution are deteriorated, and the toner flows during development, which also tends to blur the image. D
In experiments using C344, 30 μm or less, especially 20 μm
Good results were obtained with a thickness of m or less. For those having a lower viscosity than this, good results can be obtained with a thinner thickness or a thicker thickness. However, for high viscosity ones, the optimum value tends to have a narrow range.

As in the case of the conventional developing method, the narrower the gap between the photosensitive member and the developing belt, that is, the spacing, the better the resolution and the uniformity of the density of the solid portion in the image quality. In the highly viscous liquid developer used in this example, the cohesive force between the toners is strong, and like the powder developer, the toner released from the developer support or carrier particles by mechanical impact or electrostatic force is used for the development. The phenomenon that is used does not occur.
That is, development is not performed with an air layer interposed between the liquid developer layer and the photoconductor. Therefore, it is essential that the developing belt is in contact with the liquid developer layer, the liquid developer layer is in contact with the pre-wet liquid layer, and the pre-wet liquid layer is in contact with the photosensitive member. Therefore, the development gap, i.e., the distance d, must be a dimension that is equal to or less than the thickness of the liquid developer layer and the prewetting liquid layer and does not disturb the respective layers.
In this embodiment, the pre-wet liquid layer on the photoconductor 10 and the developing belt 5 are changed depending on the difference in viscosity of the liquid developer and the toner concentration.
When the liquid developer layer on 10 was brought into contact, the gap was 8
The tension of the developing belt 510 was adjusted so as to be in the range of μm to 50 μm.

Table 1 shows the results of the experiment for image formation under the above-mentioned conditions. From these results, the optimum range of the developer and the viscosity of the pre-wet liquid for the developing method of this embodiment is 100 mPa · s to 6000 mPa · s for the developer.
s, pre-wetting liquid is 0.5 mPa · s to 5 mPa · s
It was found to be between s. Regarding image quality,
Although it varies depending on the thickness of the liquid developer layer on the developing belt, the thickness of the pre-wet liquid layer, the development gap, etc., even if the various developing conditions are optimized, there is a general tendency as shown in Table 1. It was confirmed that the optimum area of the liquid developer falls within the range shown in Table 1. The silicone oil of the pre-wet liquid is DC200 series manufactured by Dow Corning, and the carrier liquid of the developing liquid is DC345 of the same company.
Was used.

[0053]

[Table 1]

According to the first embodiment of the present invention, the developing belt 510 is provided by providing the layer forming blade 504 so that the front end of the developing belt 510 contacts the developing belt 510 in the trail direction.
Since the layer thickness of the high-viscosity liquid developer 508 applied on top can be thinly and uniformly regulated, a small amount of the liquid developer 5 can be used.
08 can be uniformly supplied to the latent image surface of the photoconductor 10.

Also, according to the first embodiment, the tip 504a.
Is 10 to 10 from the contact position 504b of the developing belt 510.
By providing the layer forming blade 504 so as to project by 0 μm, it is possible to prevent the liquid developer 508 applied on the developing belt 510 from undulating.

Further, according to the first embodiment, since the layer forming blade 504 is formed of rubber that does not swell in the insulating liquid used for the liquid developer 508, the developing belt 5
It is possible to keep the layer thickness of the liquid developer 508 applied on 10 constant.

Further, according to the first embodiment, since silicon oil is used as the carrier liquid for the liquid developer,
It has the following advantages over conventional ones.

Conventional liquid developers generally use IsoparG (registered trademark: manufactured by Exxon) as a carrier liquid.
Since this Isopar has a resistance value not as high as that of silicone oil, when the toner concentration is increased, that is, when the distance between particles is reduced, the chargeability of the toner is deteriorated. Therefore, Isop
In the case of ar, the toner density is limited. On the contrary,
Since the silicone oil used in this embodiment has a sufficiently large resistance value, the toner concentration can be increased. Also,
Generally, in the case of Isopar, the toner is well dispersed, and therefore even if the toner concentration is 1 to 2%, the toners repel each other, so that the toner is uniformly dispersed. On the other hand, silicone oil has a toner concentration of 1 to 2%,
The dispersibility is not good and it will precipitate soon. However, when the toner concentration is set to 5 to 40%, the toner is densely packed and stably dispersed. Therefore, in this embodiment, a high-viscosity liquid developer in which toner is dispersed at high density is used. As a result, the amount of the developer can be significantly reduced as compared with the conventional low-concentration liquid developer, and the device can be downsized. Furthermore, since the liquid developer of this embodiment is a high-viscosity liquid, it is easier to store and handle than the conventional low-viscosity liquid developer or powder developer.

Isopar used in the conventional liquid developer is
As mentioned above, it is highly volatile and emits a foul odor,
There is a problem that it not only deteriorates the work environment but also causes pollution. On the other hand, the silicone oil used in this example is a safe liquid and is odorless, as is clear from the fact that it is used for cosmetics. The environment can be improved and pollution problems do not occur.

The first embodiment of the present invention is not limited to the above-mentioned embodiment, but various modifications can be made within the scope of the gist thereof. For example, in the above-described aspect, the developing device using the developing belt 510 formed of a flexible belt-shaped member as the developer support has been described as the developing device, but the present embodiment is not limited to this. Instead of FIG.
Like the developing device 52 shown in FIG. 5, the developing device may use the developing roller 520 formed of a rigid body or elastic body such as metal having conductivity on the developer support. However, when the developing roller 520 formed of a rigid body is used, the liquid developer layer formed on the developing roller 520 and the pre-wet liquid layer formed on the photoconductor are brought into contact with each other while maintaining a two-layer state, Further, in order to separate the two inside the pre-wet liquid layer, the developing roller 520 is disposed so as to form a minute gap, that is, a space d between the developing roller 520 and the photosensitive member, or It is necessary to use a photosensitive belt formed of a flexible belt-shaped member.

Further, in the above-mentioned embodiment, the case where the liquid developer 508 is applied to the developing belt 510 by using the developer supplying roller 506 has been described, but the present embodiment is not limited to this. Instead of the developer supply roller, for example, the liquid developer may be pumped up by a double gear pump provided by being immersed in the liquid developer stored in a tank and applied to the developing belt, or the liquid developer may be stored. The liquid developer may be applied to the developing belt by means of a bellows pump that discharges the liquid.

Next, FIG. 16 shows the second embodiment of the present invention.
It will be described with reference to FIGS. FIG. 16 is a schematic configuration diagram showing a configuration of a liquid developing device for an electrostatic latent image which is a second embodiment of the present invention, FIG. 17 is a schematic diagram of a developing device used in the liquid developing device shown in FIG. 16, and FIG. FIG. 18 is a diagram for explaining a modified example of the developing device shown in FIG. 17. Here, the same reference numerals are used for those having the same functions as those in the first embodiment.

In the electrostatic latent image liquid developing device 2 according to the second embodiment of the present invention, as shown in FIG. 16, a photoconductor 10 which is an image support, and a prewetting liquid is applied on the photoconductor 10. A pre-wetting device 20, a charging device 30 that charges the photoconductor 10, and an exposure device 4 that exposes an image on the photoconductor 10.
0 and a developing device 5 that visualizes the electrostatic latent image by supplying toner to the portion of the photoconductor 10 where the electrostatic latent image is formed.
0a, a transfer device 60 for transferring and fixing the toner on the photoconductor 10 to a predetermined paper, and a cleaning device 70 for removing the toner remaining on the photoconductor 10.

Since the electrostatic latent image liquid developing device 2 of the second embodiment of the present invention is different from the liquid developing device of the first embodiment in the developing device 50a, the description of the other parts will be omitted. The developing device 50a will be described in detail.

As shown in FIG. 17, the developing device 50a of the second embodiment has a tank 1502 for storing a high-concentration and high-viscosity liquid developer 508, a supply roller 1504 provided at an outlet of the tank 1502, Regulation blade 1 for regulating the liquid amount of the liquid developer supplied by the supply roller 1504
505, and a developing belt 1510 which is a developer support,
The developing belt 1510 is driven to rotate and the developing belt 1
Drive rollers 1512a, 1512b, 1512c for holding a part of 510 so as to abut on the photoconductor 10
A coating roller 1506 for coating the developing belt 1510 with the liquid developer 508; transport rollers 1514a, 1514b for transporting the liquid developer 508 supplied by the supply roller 1504 to the coating roller 1506; and the developing belt 1
Adjustment rollers 1516a and 1516b for adjusting the amount of liquid developer 508 applied to 510 and a scraping blade 1517 for removing the liquid developer 508 adhering to the developing belt 1510 after development are provided.

Supply roller 1504, coating roller 150
6 and unevenness of 10 to 50 μm are provided on the surfaces of the transport rollers 1514a and 1514b. By holding and transporting the liquid developer 508 in this recess, it is possible to prevent the liquid developer 508 from undulating.

The supply roller 1504 is a conveyance roller 151.
4a is arranged so as to abut the conveying roller 15a.
The liquid developer 508 stored in the tank 1502 is supplied to the transport roller 1514a by rotating in the direction opposite to the rotating direction of 14a. The regulation blade 1505 is arranged so as to contact the supply roller 1504 in the trail direction. As a result, the liquid developer 508 attached to the convex portion on the surface of the supply roller 1504 is removed, and the supply roller 1
Only the liquid developer 508 held by the concave portion on the surface of 504 is supplied to the transport roller 1514a. The supply roller 1
A liquid reservoir of the liquid developer 508 is formed at the contact start side of the contact portion between the 504 and the transport roller 1514a.
As a result, the liquid developer 508 supplied to the transport roller 1514a is adjusted to be constant and uniform.

The carrying roller 1514a is the carrying roller 15
14b, which is arranged so as to contact with the transport roller 1b.
By rotating in the opposite direction to the rotating direction of 514b,
Liquid developer 508 supplied by supply roller 1504
Are transported to the transport roller 1514b. The transport roller 1
A liquid reservoir of the liquid developer 508 is formed on the contact start side of the contact portion between the 514a and the transport roller 1514b. As a result, the liquid developer 508 conveyed to the conveyance roller 1514b is adjusted so as to be uniform and uniform.
The transport roller 1514b is disposed so as to contact the coating roller 1506, and rotates in a direction opposite to the rotation direction of the coating roller 1506, whereby the transport roller 1516 is rotated.
The liquid developer 508 supplied by the coating roller 4a
Transport to 506. A liquid pool of the liquid developer 508 is formed on the contact start side of the contact portion between the transport roller 1514b and the application roller 1506. As a result, the liquid developer 508 conveyed to the application roller 1506 is adjusted so as to be uniform and uniform. The liquid pool formed between the rollers becomes smaller as it gets closer to the application roller.

The coating roller 1506 is the developing belt 151.
The developing belt 151 is arranged so as to contact with the developing belt 151.
By rotating in the direction opposite to the rotation direction of 0, the liquid developer 508 supplied by the transport roller 1514b is applied to the surface of the developing belt 1510. As described below,
Since an elastic roller is used as the applying roller, the liquid developer 508 is applied to the applying roller 1506 and the developing belt 1510.
Between the developing belt 15 and the developing belt 15 without forming a liquid pool.
10 is applied.

Liquid developer 508 for developing belt 1510
The supply roller 1504, the coating roller 1506, and the transport rollers 1514a and 1514b are used to supply
Since the liquid developer 508 is a toner in which the toner is dispersed at a high concentration, a large amount of the developer is not required, and a small amount of the liquid developer needs to be uniformly and thinly applied to the surface of the developing belt 1510. is there. In the second embodiment of the present invention, the peripheral speeds of the supply roller 1504, the coating roller 1506, and the transport rollers 1514a and 1514b are the same as those of the developing belt 15.
It was set to be the same as the peripheral speed of 10. According to the experiments conducted by the present inventors, the transport rollers 1514a, 1514b
By rotating the developing belt 1510 at a speed different from the peripheral speed of the developing belt 1510.
It was found that the surface of No. 10 could be applied evenly and thinly.

The adjusting roller 1516a is the conveying roller 15
14b, which is arranged so as to contact with the transport roller 1b.
It rotates in the opposite direction to the rotating direction of 514b. As a result, a liquid pool of the liquid developer 508 is formed on the contact start side of the contact portion between the adjusting roller 1516a and the transport roller 1514b. As a result, the transport roller 1514b
The liquid developer 508 supplied to the coating roller 1506 is adjusted so as to be uniform and uniform. Further, the adjusting roller 1516b is arranged so as to contact the applying roller 1506, and rotates in the direction opposite to the rotating direction of the applying roller 1506. As a result, a liquid pool of the liquid developer 508 is formed on the contact start side in the contact portion between the adjusting roller 1516b and the applying roller 1506. As a result, the liquid developer 508 supplied to the developing belt 1510 by the application roller 1506 is adjusted to a constant amount and uniform.

Supply roller 1504, coating roller 150
6, the transport rollers 1514a and 1514b, and the adjusting rollers 1516a and 1516b include rigid rollers such as metal rollers and resin rollers, and elastic rollers such as single or continuous foam sponge rollers and rubber rollers. However, the coating roller 1506 includes a coating roller and a developing belt 151.
Developing belt 1 without causing a liquid pool between the developing belt 1 and
An elastic roller is used to apply liquid developer 508 to 510. In particular, it is not preferable to use a metal roller as the coating roller in order to prevent the surface of the developing belt 1510 from being scratched. A supply roller 1504, a coating roller 1506, conveyance rollers 1514a and 1514b,
Also, the adjusting rollers 1516a and 1516b must not swell into the silicone oil that is the carrier liquid of the liquid developer 508. Therefore, when using a single foam or continuous foam sponge roller, it is necessary to coat the surface of the roller with Teflon, nylon or the like. When using a rubber roller, it is necessary to use a rubber that does not swell in silicon oil.

The developing belt 1510 has a driving roller 151.
The liquid developer 508 applied by the applying roller 1506 to the surface of the photoconductor 10 is conveyed by rotating in a direction opposite to the rotation direction of the photoconductor 10 by 2a, 1512b, and 1512c. As the developing belt 1510, a flexible belt member such as a metal belt such as a seamless nickel belt, a polyimide film belt, a resin belt such as a PET film belt, and a rubber belt is used. This makes it possible to disperse the contact pressure when the liquid developer layer formed on the developing belt 1510 and the pre-wet liquid layer formed on the photoconductor 10 are dispersed, so that it is formed on the developing belt 1510. The liquid developer layer and the pre-wet liquid layer formed on the photoconductor 10 are contacted while maintaining a two-layer state so that the layers can be distinguished from each other, and both are separated inside the pre-wet liquid layer. be able to.

The developing belt 1510 must be capable of applying an electric developing bias. Therefore,
In the case of using a resin belt or a rubber belt, it is necessary to reduce the electric resistance value by subjecting the surface of the belt to conductive processing or adding conductive fine particles to the material of the belt. When the belt itself has conductivity, the driving rollers 1512a, 1
As the rollers 512b and 1512c, rubber rollers having a low electric resistance value to which conductive particles are added so that a developing bias can be applied are used. When the belt surface is subjected to conductive processing, a conductor that comes into contact with the belt surface is provided and a bias voltage is applied to this conductor.

Next, the operation of the liquid developing apparatus for electrostatic latent image according to the second embodiment of the present invention will be described. In the electrostatic latent image liquid developing device 2 of the second embodiment, as in the first embodiment, the electrostatic latent image is formed on the surface of the photoconductor 10 and the pre-wet liquid is applied thereto, and then the developing device 50a. To visualize the electrostatic latent image. Liquid developer 50 stored in tank 1502
8 is a feeding roller 1504 and a conveying roller 1514.
a is supplied to the coating roller a and then is transported to the coating roller 1506 via the transport roller 1514b. The liquid developer 508 thus conveyed to the coating roller 1506 via the plurality of rollers is thinly and evenly coated on the developing belt 1510 to form a thin layer on the developing belt 1510. The liquid developer 508 supplied to the developing belt 1510 is adjusted by the adjusting rollers 1516a and 1516b so that the liquid amount is always constant and uniform.

Next, the liquid developer layer formed on the developing belt 1510 is brought close to the electrostatic latent image formed on the surface of the photoconductor 10 as shown in FIG. The charged toner is moved onto the photoconductor 10 to form a toner image. After that, the toner image is transferred and fixed according to the same steps as in the liquid developing apparatus of the first embodiment.

According to the second embodiment of the present invention, the application roller 15 for applying the liquid developer 508 to the developing belt 1510.
06, transport rollers 1514a and 1514b for transporting the liquid developer 508 to the application roller 1506, and the liquid developer 5 stored in the tank 1502 on the transport roller 1514a.
By using the developing device 50a provided with the supply roller 1504 for supplying 08, the liquid developer 508 can be applied thinly and evenly to the developing belt 1510, so that a small amount of liquid can be applied to the latent image surface of the photoconductor 10. The developer can be uniformly supplied.

Further, according to the second embodiment, the adjusting roller 1
516a and 1516b are respectively conveyed by the conveying roller 1514.
b, by using the developing device 50a that is brought into contact with the application roller 1506, the contact start side of the contact portion between the adjustment roller 1516a and the transport roller 1514b and the contact portion between the adjustment roller 1516b and the application roller 1506. A liquid reservoir of the liquid developer is formed on the contact start side in (1), whereby a constant amount of the liquid developer can be uniformly supplied to the latent image surface of the photoconductor 10.

The second embodiment of the present invention is not limited to the above embodiment, but various modifications can be made within the scope of the gist thereof. For example, in the above-described aspect of the second embodiment, as the developing device, the supply roller 1504 supplies the liquid developer 508 to the conveyance roller 1514a, and the conveyance roller 1
Although the one which is applied to the developing belt 1510 after being conveyed to the applying roller 1506 via 514b has been described.
The present embodiment is not limited to this. The developing device may supply the liquid developer to the developing belt 1510 via at least two rollers. Therefore, the supply roller 1504 directly applies the coating roller 1506.
Liquid developer 508 to the developing belt 15
10 may be applied, and the supply roller 150 may be used.
The liquid developer 508 supplied by the No. 4 is supplied to the coating roller 1506 via one or three or more conveying rollers,
Then, it may be applied to the developing belt 1510.

Further, in the above-mentioned aspect of the second embodiment, the developing device in which the adjusting rollers 1516a and 1516b are brought into contact with the conveying roller 1514b and the applying roller 1506 respectively has been described. It is not limited. The adjusting roller is the developing belt 151.
It is arranged according to the thickness of the liquid developer layer formed on the surface of the liquid crystal layer, and may not be arranged if not necessary. Further, the means for supplying the liquid developer 508 to the conveyance roller is
The supply roller is not limited to the supply roller, and may be, for example, a supply roller that supplies the transfer roller with a bellows pump.

Further, in the above-described aspect of the second embodiment, the developing device for removing the liquid developer 508 adhering to the developing belt 1510 by the scraping blade 1517 has been described, but the present invention is not limited to this. However, like the developing device 52a shown in FIG. 18, the scraping roller 15 arranged so that the liquid developer 508 attached to the developing belt 1510 is brought into contact with the developing belt 1510.
It may be removed by 19.

Next, a third embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 19 is a schematic configuration diagram showing a configuration of a liquid developing device for an electrostatic latent image which is a third embodiment of the present invention, FIG. 20 is a schematic diagram of a developing device used in the liquid developing device shown in FIG. 19, and FIG. 20 is a schematic view of a supply roller used in the developing device shown in FIG. 20, and FIGS.
FIG. 9 is a diagram for explaining a modified example of the developing device shown in FIG. Here, the reference numerals in the figure use the same numerals for members having the same functions as those in the second embodiment.

The electrostatic latent image liquid developing apparatus 3 according to the third embodiment of the present invention, as shown in FIG. A pre-wetting device 20, a charging device 30 that charges the photoconductor 10, and an exposure device 4 that exposes an image on the photoconductor 10.
0 and a developing device 5 that visualizes the electrostatic latent image by supplying toner to the portion of the photoconductor 10 where the electrostatic latent image is formed.
0b, a transfer device 60 for transferring and fixing the toner on the photoconductor 10 to a predetermined paper, and a cleaning device 70 for removing the toner remaining on the photoconductor 10.

The electrostatic latent image liquid developing device of the third embodiment is different from the liquid developing device of the second embodiment in the developing device 50b.
Therefore, omit the explanation of other parts,
The developing device 50b will be described in detail.

As shown in FIG. 20, the developing device 50b of the third embodiment has a tank 2502 for storing a high-concentration and high-viscosity liquid developer 508 and a liquid developer 508 partially stored in the tank 2502. In the tank 2502, the supply roller 2504, which is disposed so as to be immersed, and the supply roller 2
Refresh roller 25 pressed by 504 and arranged
06, the developing belt 2510 which is a developer support, and the developing belt 2510 is rotationally driven, and the developing belt 2
Driving rollers 2512a, 25 for holding a part of 510 in contact with the photoconductor 10 and the supply roller 2504
12b and 2512c, and a scraping blade 2514 for removing the liquid developer 508 adhering to the developing belt 2510 after development.

As shown in FIG. 21, the supply roller 2504 is composed of a cylindrical body 2504a and a sponge 2504b covering the cylindrical body 2504a. The supply roller 2504 rotates in the direction opposite to the rotation direction of the developing belt 2510 to absorb the liquid developer 508 stored in the tank 2502 into the sponge 2504b and the liquid developer absorbed into the sponge 2504b. The agent 508 is supplied to the developing belt 2510. Sponge 25
The thickness t of 04b is preferably 1 to 4 mm. Sponge 2
If the wall thickness t of 504b is less than 1 mm, the supply roller 25
04 becomes difficult to manufacture. On the other hand, when the thickness t of the sponge 2504b is thicker than 4 mm, the liquid developer 508 which is not discharged to the outside remains inside the sponge 2504b, which may cause the sponge 2504 to be clogged.
The liquid amount of the liquid developer 508 held by the sponge 2504b is determined by the wall thickness t of the sponge 2504b, the porosity, and the diameter of the pores. Therefore, the thickness t of the sponge 2504b, the porosity, and the diameter of the pores should be determined in consideration of the amount of the liquid developer 508 applied to the developing belt 2510. According to experiments conducted by the present inventors, the sponge 250
4b has a thickness t of 1 mm, a porosity of 80%, and a pore diameter of 3
When 0 μm, a small amount of highly concentrated and highly viscous liquid developer 50
No. 8 could be applied onto the developing belt 2510 with the least unevenness. Incidentally, since the diameter of the pores of the sponge 2504b is generally small, it is possible to prevent the liquid developer 508 from undulating when releasing the liquid developer 508.

The refreshing roller 2506 rotates in the direction opposite to the rotating direction of the supply roller 2504, and thereby discharges all the liquid developer 508 remaining in the sponge 2504b of the supply roller 2504. As a result, the liquid developer 508 in the sponge 2504b is constantly circulated.

The developing belt 2510 has a driving roller 251.
The liquid developer 508 supplied by the supply roller 2504 is conveyed to the surface of the photoconductor 10 by rotating in the opposite direction to the rotation direction of the photoconductor 10 by 2a, 2512b, and 2512c. The material, function, and the like of the developing belt 2510 are the same as those in the second embodiment, so detailed description thereof will be omitted.

Next, the operation of the electrostatic latent image liquid developing device of the third embodiment of the present invention will be described. In the electrostatic latent image liquid developing device of the third embodiment, as in the first embodiment, an electrostatic latent image is formed on the surface of the photoconductor 10 and the pre-wet liquid is applied thereto, and then the developing device 50b is used to remove the electrostatic latent image. Visualize the electric latent image. The liquid developer 508 stored in the tank 2502 is
It is absorbed by the supply roller 2504, and then the developing belt 2
Supplied on 510. By setting the thickness t of the sponge 2504b of the supply roller 2504b, the porosity, and the diameter of the pores to predetermined values, a small amount of the liquid developer 508 can be applied thinly and evenly to the developing belt 2510. A thin liquid developer layer is formed on the developing belt 2510. The sponge 504 of the supply roller 2504
The liquid developer 508 remaining in b is discharged by the refresh roller 506. As a result, the new liquid developer 508 is always applied to the developing belt 510.
After that, the toner image is transferred and fixed according to the same steps as in the liquid developing apparatus of the first embodiment.

According to the third embodiment of the present invention, the sponge 2504b has the wall thickness t, the porosity and the diameter of the pores set to predetermined values.
By using the developing device 50b which supplies the high-concentration and high-viscosity liquid developer 508 to the developing belt 2510 by the supply roller 2504 coated with
8 can be thinly and evenly applied to the developing belt 2510. Therefore, the developing belt 2510 can uniformly supply a small amount of high-concentration and high-viscosity liquid developer to the latent image surface of the photoconductor 10.

Further, according to the third embodiment, the supply roller 2
By using the developing device 50b in which the refreshing roller 2506 that squeezes out the liquid developer 508 held by 504 is pressed against the supply roller 2504, the supply roller 25
04 liquid sponge 2504b remaining liquid developer 50
All 8 can be exhaled for each rotation. Therefore, the sponge can be prevented from being clogged, and new developer can be constantly supplied to the developing belt 2510.

Next, another mode of the third embodiment of the present invention will be described with reference to FIG. FIG. 22 is a schematic view of another embodiment of a developing device used in the electrostatic latent image liquid developing device of the third embodiment. Incidentally, in the liquid latent image developing device of this aspect, those having the same functions as those of the third embodiment described above will be described in detail by giving the same reference numerals or corresponding reference numerals. Omit it.

The electrostatic latent image liquid developing apparatus according to the second aspect of the third embodiment of the present invention is different from that of the first aspect shown in FIG. 20 in that as shown in FIG. Device 50b
Instead, the developing device 52b is used. More specifically, the developing device 52b of the second aspect is different from the developing device 50b of the first aspect, as shown in FIG. 22, is supplied between the supply roller 2504 and the developing belt 2510 by the supply roller 2504. That is, a transport roller 2522 is provided for transporting the liquid developer 508 thus produced to the developing belt 2510.

The developing device 52b having the above structure supplies the liquid developer 508 stored in the tank 2502 to the supply roller 2
It is supplied to the transport roller 2522 by 504. And
The transport roller 2522 transports the liquid developer 508 supplied by the supply roller 2504 to the developing belt 2510. Since the other operations of the electrostatic latent image liquid developing device which is the second aspect of the third embodiment are the same as those of the first aspect of the third embodiment, detailed description thereof will be omitted.

According to the second aspect of the third embodiment, by using the developing device 52b for applying the liquid developer 508 supplied by the supply roller 2504 to the developing belt 2510 via the conveying roller 2522, the developing belt is used. 2510
A small amount of high-concentration and high-viscosity liquid developer can be evenly and uniformly applied, and as a result, a small amount of high-concentration and high-viscosity liquid developer can be more uniformly supplied to the latent image surface of the photoconductor 10. You can Other effects are similar to those of the first aspect of the third embodiment.

In the second aspect of the third embodiment, the supply roller 2504 and the developing belt 251 are used as the developing device 52b.
Although one transfer roller 2522 is interposed between the transfer rollers and 0, the present embodiment is not limited to this. The developing device includes a supply roller 2504 and a developing belt 2.
Two or more conveying rollers may be interposed between the sheet and 510. As the number of the transport rollers is increased, the high-concentration and high-viscosity liquid developer can be evenly and uniformly applied onto the developer support. However, considering the downsizing of the apparatus, there is an optimum number of rollers for forming the thin developer layer.

The third embodiment of the present invention is not limited to each of the above-mentioned modes, but various modifications can be made within the scope of the gist thereof. For example, in each aspect of the third embodiment described above, the cylindrical body 2 is used as the supply roller used in the developing device.
504a and sponge 25 covering the cylindrical body 2504a
However, the present embodiment is not limited to this. The supply roller may be composed of a cylindrical body and a sponge 2504b covering the cylindrical body. Further, although the supply roller 2504 is described as being disposed by being partially immersed in the liquid developer 508 stored in the tank 2502, the present embodiment is not limited to this.
The supply roller may be disposed between the transport roller and the developing belt, for example. In this case, the liquid amount of the liquid developer transported by the transport roller can be adjusted by the supply roller to supply a small amount of the liquid developer to the developing belt.

In each of the aspects of the third embodiment described above, the developing device using the developing belt 2510 composed of a flexible member as the developer support has been described. It is not limited to this. The developing device may use a developing roller formed of a rigid body or an elastic body such as a metal having conductivity on the developer support. However, when a developing roller formed of a rigid body is used, the liquid developer layer formed on the developing roller and the pre-wet liquid layer formed on the image support are contacted while maintaining a two-layer state, and In order to separate the two inside the pre-wet liquid layer, the developing roller is arranged so as to form a minute gap, that is, a space d between the developing roller and the photosensitive member, or the developing device shown in FIG. 54b, the developing roller 2540 is replaced with the driving rollers 122a, 12
It is necessary to contact the photosensitive belt 12, which is an image support, which is composed of a flexible member that is driven to rotate by 2b and 122c.

Furthermore, in each aspect of the above third embodiment,
As the developing device, the one in which the liquid developer 508 adhering to the developing belt 2510 is removed by the scraping blade 2514 has been described.
The liquid developer 508 attached to 0 may be removed by a scraping roller provided in contact with the developing belt 2510.

Next, a fourth embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 24 is a schematic configuration diagram showing a first mode of a liquid developing apparatus for an electrostatic latent image which is a fourth embodiment of the present invention, and FIG. 25 is a schematic configuration diagram showing a second mode of the fourth embodiment. FIG. 26 is a schematic configuration diagram showing a third aspect of the fourth embodiment. Here, the reference numerals in the figure use the same numerals for members having the same functions as in the first embodiment.

As shown in FIG. 24, the electrostatic latent image liquid developing device 4 according to the first aspect of the fourth embodiment of the present invention includes a photoconductor 10 which is an image support and a pretreatment on the photoconductor 10. A pre-wetting device 20 that applies a wetting liquid, a charging device 30 that charges the photoconductor 10, an exposure device 40 that exposes an image on the photoconductor 10, and a portion of the photoconductor 10 where an electrostatic latent image is formed. A developing device 50c that visualizes the electrostatic latent image by supplying toner, a transfer device 60a that transfers and fixes the toner on the photoconductor 10 to a predetermined paper, and a predetermined paper is conveyed to the transfer device 60. Paper feeding device 610, and cleaning device 7 for removing toner remaining on photoconductor 10
0 and a neutralization device 80 that neutralizes the charged photoconductor 10.

The electrostatic latent image liquid developing device of the first embodiment of the fourth embodiment differs from the liquid developing device of the first embodiment in the developing device 50c and the transfer device 60a. The description is omitted, and the transfer device 60a with the developing device 50c will be described in detail.

The developing device 50c according to the first aspect of the fourth embodiment.
Is a developing belt 3510 which is a developer support, and rotationally drives the developing belt 3510 and
Drive rollers 3512a, 3512b, and 3512c for holding a part of the toner in contact with the photoconductor 10 and a supply device 3 for applying the liquid developer 508 to the developing belt 3510.
51, and a scraping blade 3514 for removing the liquid developer 508 adhering to the developing belt 3510 after development.

The supply device 351 includes four developing cartridges 351a and 351 which are liquid developer supplying means for color.
b, 351c and 351d are provided on the rotating shaft 3509. Each developer cartridge contains liquid developer 508
3502 for storing a sheet and a conveying roller 350 described later.
4, the supply roller 3502a provided at the discharge port of the tank 3502 for supplying the liquid developer 508 to
A transport roller 3504 that transports the liquid developer 508 supplied by 502 a to a coating roller 3506 described below, and a coating roller 3506 that coats the liquid developer 508 transported by the transport roller 3504 on the developing belt 3510. The liquid developer 508a containing yellow toner is stored in the tank 3502 of the developing cartridge 351a, the liquid developer 508b containing magenta toner is stored in the tank 3502 of the developing cartridge 351b, and the cyan toner is stored in tank 3502 of the developing cartridge 351c. Liquid developer 508c containing and developing cartridge 351
Liquid developers 508d containing black toner are stored in the respective tanks 3502 of d. Supply device 35
1 rotates the rotary shaft 3509 to rotationally move the developing cartridge, so that the coating roller 3506 of one of the developing cartridges contacts the developing belt 3510. As a result, the liquid developer 508 containing toner of a desired color is applied to the developing belt 3510.

The transport roller 3504 is a coating roller 350.
By rotating in the direction opposite to the rotating direction of 6, the liquid developer 508 supplied by the supply roller 3502a is conveyed to the surface of the coating roller 3506. Coating roller 35
By rotating in the direction opposite to the rotating direction of the developing belt 3510, 06 applies the liquid developer 508 carried by the carrying roller 3504 to the surface of the developing belt 3510. The feed roller 3504 and the application roller 3506 are used to supply the liquid developer 508 to the developing belt 3510 because the liquid developer 508 is a toner in which the toner is dispersed in a high concentration, and therefore a large amount of developer is required. This is because, for this reason, the roller is the most effective way to apply the developer evenly to the surface of the developing belt 3510. Note that one or a plurality of transport rollers that transport the liquid developer 508 may be provided between the transport roller 3504 and the application roller 3506.

The developing belt 3510 has a driving roller 351.
The liquid developer 508 coated by the coating roller 3504 on the surface of the photoconductor 10 is conveyed by rotating in a direction opposite to the rotation direction of the photoconductor 10 by 2a, 3512b, and 3512c. As in the first embodiment, the developing belt 3510 is required to have flexibility and conductivity. Therefore, detailed description of the developing belt 3510 will be omitted.

The transfer device 60a according to the first aspect of the fourth embodiment.
Is an intermediate transfer belt 3602 that is an intermediate transfer member, and a drive roller 3604 that rotationally drives the intermediate transfer belt 3602.
a, 3604b, 3604c and the intermediate transfer belt 360
Holding rollers 3605a and 3605b that hold a part of the photosensitive drum 10 so as to abut on the photoconductor 10, and the intermediate transfer belt 3
A corona discharger 3606 for charging 602 with an electric charge having a polarity opposite to that of the toner, and a secondary transfer roller 3 which is a secondary transfer member provided so as to be separable from and in contact with the intermediate transfer belt 3602.
And 603.

The intermediate transfer belt 3602 is driven by the driving roller 3
Photoconductor 10 by 604a, 3604b, 3604c
Rotates in the direction opposite to the rotation direction of. Intermediate transfer belt 36
For 02, a flexible belt member such as a metal belt such as a seamless nickel belt, a polyimide film belt, a resin belt such as a PET film belt, and a rubber belt is used. This makes it possible to disperse the contact pressure when the toner image formed on the photoconductor 10 and the intermediate transfer belt 3602 come into contact with each other. When a resin belt or a rubber belt is used, it is necessary to make the surface of the belt conductive or add conductive fine particles to the material of the belt to obtain a desired electric resistance value.

On the intermediate transfer belt 3602, Teflon,
A surface layer having good releasability such as silicon is formed. This is to weaken the physical adhesion of the toner to the intermediate transfer belt 3602 and facilitate the movement of the toner to the paper.

The secondary transfer roller 3603 rotates in the direction opposite to the rotation direction of the intermediate transfer belt 3602, so that the paper conveyed by the paper feeding device 610 is placed between the intermediate transfer belt 3602 and the secondary transfer roller 3603. Send in. At this time, the secondary transfer roller 3603 is pressed against the intermediate transfer belt 3602 via the paper. Secondary transfer roller 36
A secondary transfer bias is applied to 03, and the intermediate transfer member 36
The toner image formed on 02 is transferred to paper. And
The toner image is fixed on the paper by a fixing device (not shown). A fixing heater may be provided inside the driving roller 3604a to heat the toner on the intermediate transfer belt 3602 so that the toner image formed on the intermediate transfer belt 3602 is transferred onto the paper and fixed at the same time. . Further, a fixing heater may be provided inside the drive roller 3604a and the secondary transfer roller 3603.

Next, the operation of the electrostatic latent image liquid developing device 4 according to the first aspect of the fourth embodiment of the present invention will be described.
Liquid developing device 4 for electrostatic latent image, which is the first mode of the fourth embodiment
In the same manner as in the first embodiment, the electrostatic latent image is formed on the surface of the photoconductor 10, the pre-wetting liquid is applied, and then the electrostatic latent image is visualized by the developing device 50c. Supply roller 350
The liquid developer 508 supplied to the carrying roller 3504 by the 2a is carried to the applying roller 3506 and then applied to the developing belt 3510. The liquid developer 508 thus conveyed to the developing belt 3510 via the rollers.
Is thinly and evenly applied to the developing belt 3510 to form a thin layer on the developing belt 3510. The supply device 351 is
By rotating the rotary shaft 3509 to rotationally move the developing cartridge, one of the developing cartridges 351
a to 351d of the coating roller 3506 and the developing belt 351
Abut 0. As a result, the liquid developer 508 containing toner of any one of yellow, magenta, cyan, and black is thinly and evenly applied to the developing belt 3510.

Next, the liquid developer layer formed on the developing belt 3510 is brought close to the electrostatic latent image formed on the surface of the photoconductor 10 as shown in FIG. The charged toner is moved onto the photoconductor 10 to form a toner image.

Next, the toner image formed on the photoconductor 10 is primarily transferred by the transfer device 60a onto the intermediate transfer belt 3602 which is an intermediate transfer member. The toner image formed on the photoconductor 10 is not the roller to which the voltage is applied as shown in FIG. 3E, that is, the holding rollers 3605a and 3605.
Instead of applying voltage to 05b, the toner image formed on the photoconductor 10 and the intermediate transfer belt 36 charged by the corona discharger 3606 with an electric charge having a polarity opposite to that of the toner.
Electrostatic force generated between the intermediate transfer belt 3 and the intermediate transfer belt 3
It moves onto 602 and is primarily transferred. On the other hand, the photoconductor 10
The liquid developer 508 remaining on the photoconductor 10 is removed by the cleaning device 70, and then the static eliminator 80 is removed.
Is discharged by. Then, after rotating the developing cartridge to switch the developing cartridge abutting against the developing belt 3510, the above cycle from charging to discharging is repeated again, and thereby, yellow, magenta, cyan, and black are transferred onto the intermediate transfer belt 3602. Toner images are transferred one after another. As a result, a toner image corresponding to colorization is formed on the intermediate transfer belt 3602.

Next, the transfer device 60a secondarily transfers the color toner image formed on the intermediate transfer belt 3602 to a recording medium, that is, paper. Intermediate transfer belt 3
The toner image corresponding to the color formed on the 602 is
By the pressing force of the secondary transfer roller 3603 on the intermediate transfer belt 3602 and the bias voltage applied to the secondary transfer roller 3603, the secondary transfer roller 3603 is separated from the intermediate transfer belt 3602 having a surface layer having good releasability, and the paper feeding device 610 is used. Conveyed intermediate transfer belt 3602 and secondary transfer roller 3603
Then, it is transferred onto the paper sent between and and is secondarily transferred. After that, as shown in FIG. 3F, a fixing device thermally fuses and fixes. Thereby, a color image can be formed on the paper. A fixing heater is provided inside the drive roller 3604a and / or the secondary transfer roller 3603,
When the toner on the intermediate transfer belt 3602 is heated, the toner image formed on the intermediate transfer body 3602 can be transferred onto the paper and fixed at the same time.

According to the first aspect of the fourth embodiment of the present invention,
The color liquid developers 508a to 508d are applied to the developing belt 3
A plurality of developing cartridges 351a to 351a to be supplied to 510
Since 51d is rotated and switched to sequentially bring one developing cartridge into contact with the developing belt 3510 to perform development, only one developer support is required, and therefore the apparatus can be downsized.

Next, the second mode of the fourth embodiment will be described with reference to FIG.
This will be described with reference to FIG. FIG. 25 is a schematic view of a liquid developing device for an electrostatic latent image which is a second aspect of the fourth embodiment. Incidentally, in the electrostatic latent image liquid developing apparatus which is the second aspect of the fourth embodiment, those having the same functions as those of the first aspect of the fourth embodiment are designated by the same reference numerals or corresponding reference numerals. Therefore, detailed description thereof will be omitted.

The electrostatic latent image liquid developing device 5 of the second embodiment of the fourth embodiment is different from that of the first embodiment of the fourth embodiment in that, as shown in FIG.
A supply device 3 in which one developing cartridge is sequentially brought into contact with the developing belt 3510 by rotationally moving and switching 351d.
Instead of the developing device 50c provided with 51, the developing device 52c provided with the supply device 353 in which the developing cartridges 353a to 353d are moved in parallel and switched to sequentially bring one developing cartridge into contact with the developing belt 3510 is used. .

The supply device 353 includes a parallel moving device (not shown) and developing cartridges 353a, 353b, 353 held by the parallel moving device and arranged in parallel.
c, 353d and a cam 3529. The parallel moving device moves the developing cartridges 353a to 353d in parallel to sequentially move one developing cartridge to the developing belt 351.
It moves to the contact position with 0. The cam 3529 rotates to move the developing cartridge, which has been moved to the contact position with the developing belt 3510 by the parallel moving device, to the developing belt 3.
Abut 510.

In the developing device 52c having the above structure, the parallel moving device moves the developing cartridges 353a to 353d in parallel to sequentially move one developing cartridge to the contact position with the developing belt 3510, and the cam 3529 moves this developing cartridge. It contacts the developing belt 3510.
As a result, the liquid developer 508 containing toner of a desired color can be applied to the developing belt 3510. The other operations of the electrostatic latent image liquid developing device 5, which is the second aspect of the fourth embodiment, are the same as those of the first aspect of the fourth embodiment, so a detailed description thereof will be omitted. .

According to the second aspect of the fourth embodiment, a plurality of developing cartridges 353a to 353d for supplying the color liquid developers 508a to 508d to the developing belt 3510 are moved in parallel and switched to sequentially change one developing cartridge. By contacting the developing belt 3510 and developing, only one developer support is required, and therefore the size of the apparatus can be reduced. The other effects are similar to those of the first aspect of the fourth embodiment.

Next, the third mode of the fourth embodiment will be described with reference to FIG.
This will be described with reference to FIG. FIG. 26 is a schematic view of a liquid developing device for an electrostatic latent image which is a third aspect of the fourth embodiment of the present invention. Incidentally, in the electrostatic latent image liquid developing apparatus which is the third aspect of the fourth embodiment, those having the same functions as those of the first aspect of the fourth embodiment are designated by the same reference numerals or corresponding reference numerals. Therefore, detailed description thereof will be omitted.

The electrostatic latent image liquid developing device 6 according to the third aspect of the fourth embodiment differs from that of the first aspect of the fourth embodiment in that the developing cartridges 351a to 351a-3 shown in FIG.
A supply device 351 for rotating and switching 51d to sequentially contact one developing cartridge with the developing belt 3510.
26, instead of the developing device 50c including the developing belt 5010, a developing belt 3510 is provided to the developing cartridges 355a to 355a.
Developing device 54c provided with a separating / connecting means for separating and contacting 5d in sequence
Was used.

The developing device 54c includes a developing belt 3540, which is a developer supporting member, and driving rollers 3542a and 354 for rotating and driving the developing belt 3540 and holding a part of the developing belt 3540 so as to abut on the photosensitive member 10.
2b and separating / contacting rollers 3544a and 354 serving as separating / contacting means.
4b, 3544c and 3544d, and a scraping blade 3514 for removing the liquid developer 508 adhering to the developing belt 3510 after development.

The separating / contacting roller 3544a is the developing belt 35.
40 is driven to rotate, and a part of the developing belt 3540 is brought into contact with and separated from the coating roller 3506 of the developing cartridge 355a. The separating / contacting roller 3544b rotationally drives the developing belt 3540 and also separates / contacts a part of the developing belt 3540 from / to the coating roller 3506 of the developing cartridge 355b.
The separating / contacting roller 3544c rotationally drives the developing belt 3540 and also separates / contacts a part of the developing belt 3540 from / to the coating roller 3506 of the developing cartridge 355c. The separating / contacting roller 3544d drives the developing belt 3540 to rotate, and also causes a part of the developing belt 3540 to develop.
The coating roller 3506 of 55d is brought into contact with or separated from the coating roller 3506.

In the developing device 54c having the above-mentioned structure, the developing belt 3540 is constituted by the separating / contacting rollers 3544a to 3544d.
A part of the above is sequentially brought into contact with the developing cartridges 355a to 355d. As a result, the liquid developer 508 containing toner of a desired color can be applied to the developing belt 3540. The other operations of the electrostatic latent image liquid developing device 6 of the third aspect of the fourth embodiment are the same as those of the first aspect of the fourth embodiment, and therefore detailed description thereof will be omitted.

According to the liquid developing apparatus of the third aspect of the fourth embodiment, the developing cartridges 355a to 355 for supplying the color liquid developers 508a to 508d to the developing belt 3540.
By developing by making the 55d and the developing belt 3540 contact and separate from each other, it is possible to reduce the size of the apparatus because only one developer support is required. The other effects are similar to those of the first aspect of the fourth embodiment.

In each of the embodiments of the above-mentioned fourth embodiment, as the developing device, a developing cartridge for supplying a liquid developer containing yellow toner to the developing belt, and a liquid developer containing magenta toner for the developing belt. The developing cartridge for supplying, the developing cartridge for supplying the liquid developer containing the cyan toner to the developing belt, and the developing cartridge for supplying the liquid developer containing the black toner to the developing belt have been described. The embodiment is not limited to this, and the developing device may be provided with two or three developing cartridges for supplying a liquid developer containing a toner of a desired color to the developing belt as needed.

In each of the aspects of the fourth embodiment, the supply roller 3502 is used as the developing cartridge of the developing device.
Although the liquid developer 508 supplied to the conveying roller 3504 by a is applied to the developing belt after being conveyed to the applying roller 3506, the present embodiment is not limited to this. The developing cartridge may be one that supplies the liquid developer 508 to the developing belt by using a roller. Further, the liquid developer 508 is transferred to the transport roller 3
The means for supplying 504 is not limited to the supply roller 3502a, and may be, for example, a means for supplying the carrier roller 3504 with a bellows pump.

Furthermore, in each aspect of the above-mentioned fourth embodiment,
As the developing device, the liquid developer 50 attached to the developing belt
However, the present embodiment is not limited to this, and the developing device is the liquid developer 5 attached to the developing belt.
08 may be removed by a scraping roller provided in contact with the developing belt.

Furthermore, in each aspect of the above-mentioned fourth embodiment,
As the transfer device, the one in which the toner image formed on the photoconductor 10 is primarily transferred to the intermediate transfer member and then the toner image primarily transferred to the intermediate transfer member is secondarily transferred to the recording medium has been described. The example is not limited to this,
It may be anything as long as it can transfer the toner image formed on the photoconductor to the recording medium. In addition, although the electrostatic transfer was explained as the primary transfer onto the intermediate transfer member, it may be adhesive transfer using an adhesive.

The present invention is not limited to the above embodiments, but various modifications can be made within the scope of the gist thereof. For example, in each of the above-described embodiments, the pre-wet liquid supply member 202 is used as the pre-wetting device, and
Although the case where the pre-wet liquid 220 is applied to the surface of No. 0 has been described, the present invention is not limited to this. The pre-wetting device may be one that can apply a constant amount of the pre-wetting liquid to the surface of the photoconductor uniformly. For example, the pre-wetting liquid may be applied by ejecting the pre-wetting liquid from a plurality of nozzles arranged in the axial direction, or the pre-wetting liquid may be applied by a sponge roller or the like.

In each of the above embodiments, the exposure device 40
The image was exposed on the image support charged by the above, and then the pre-wetting device 20 was used to apply the pre-wet liquid 220 on the image support, but the present invention is not limited to this. Pre-wet liquid 220
The coating may be performed before the developing step. In addition, the viscosity of the pre-wet liquid is 0.5 to 5 mPa.
s, electric resistance is 10 ¹² Ωcm or more, boiling point is 100 to 25
Silicon may not be the main component as long as it has a surface tension of 21 dyn / cm or less at 0 ° C. Furthermore, when the surface of the image support is coated with a material having releasability, a pre-wetting device is not particularly required.

Furthermore, in each of the above embodiments, the case where the organic photoconductor is used as the image support has been described, but the present invention is not limited to this, and the image support is
It may be an electrostatic recording paper such as an electrostatic plotter, or an electrophotographic recording medium in which an insulating layer is formed on a conductor that directly forms an electrostatic latent image such as various photoconductors used in the Carlson method or ionography.

The present invention is not limited to the above embodiments, and the viscosity of the high-viscosity developer may be 10,000 mPa · s as long as the layer thickness of the liquid developer is 5 to 40 μm. . At present, a developer with a high viscosity of 6000 mPa · s or more is difficult to agitate between the carrier liquid and the toner, so it is thought to be costly. However, if it becomes available at a low cost, it will be even at 6000 mPa · s or more. Good. If the viscosity exceeds 10,000 mPa · s, it becomes unrealistic. Further, the carrier liquid of the liquid developer is not limited to silicone oil.

Further, in each of the above embodiments, the developing device using the developing belt composed of a flexible member as the developer support has been described, but the present invention is not limited to this. Not a thing. The developing device may use a developing roller formed of a rigid body or an elastic body such as a metal having conductivity on the developer support. However, when a developing roller formed of a rigid body is used, the liquid developer layer formed on the developing roller and the pre-wet liquid layer formed on the photoreceptor are contacted while maintaining a two-layer state, and In order to separate the developing roller from the inside of the pre-wet liquid layer, it is necessary to dispose the developing roller so as to form a minute gap, that is, a space d between the developing roller and the photosensitive member.

[0136]

As described above, according to the electrostatic latent image liquid developing apparatus of the present invention, the high viscosity liquid developer in which the toner is dispersed at a high concentration is developed into a thin layer by the above structure. As a result, a small amount of high-concentration and high-viscosity liquid developer can be supplied to the latent image surface of the image support, and the resolution and the size can be easily reduced as compared with the conventional liquid developing device, and the pollution is low. It is possible to provide a liquid developing device for an electrostatic latent image that can be converted into a liquid.

When a layered blade is provided as the coating means so that the tip end thereof contacts the developer support in the trail direction, the layer thickness of the high-viscosity liquid developer coated on the developer support is adjusted. Since it can be thinly and uniformly regulated, it is possible to provide an electrostatic latent image liquid developing device capable of uniformly supplying a small amount of liquid developer to the latent image surface of the image support.

Also, when the liquid developer is supplied to the developer support through at least two rollers as the coating means, the liquid developer layer on the developer support can be made thin and uniform. A very small amount of the liquid developer required for the latent image surface of the image support can be uniformly supplied, and when any roller is brought into contact with at least one adjusting roller, the liquid developer can be supplied. It is possible to provide a liquid developing device for an electrostatic latent image that can make the supply amount of the liquid developer more uniform.

Furthermore, even when a roller having a thin sponge layer is used as the coating means, a very small amount of liquid developer can be coated thinly and evenly on the surface of the developer support,
Also, when the refresh roller contacts the roller,
It is possible to provide a liquid developing device for an electrostatic latent image which can prevent the sponge of the coating roller from being clogged and can always supply a new developer to the developer support.

When the pre-wetting means for applying the pre-wetting liquid is provided on the image support, the electrostatic latent image capable of preventing the toner from adhering to the non-image portion on the surface of the image support. It is possible to provide the liquid developing device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a liquid developing device for an electrostatic latent image that is a first embodiment of the present invention.

FIG. 2 is a schematic perspective view of a pre-wetting device used in the electrostatic latent image liquid developing device shown in FIG.

FIG. 3 is a diagram for explaining the operation of the liquid latent image developing device shown in FIG.

FIG. 4 is a diagram for explaining the operation of the pre-wetting device shown in FIG.

FIG. 5 is a diagram showing the flow of the pre-wet liquid when the pre-wet liquid supply member is brought into contact with the photoconductor.

FIG. 6 is a diagram for explaining the entire developing process.

FIG. 7 is a diagram showing a state of an approaching process.

FIG. 8 is a diagram showing a state of a toner movement process.

FIG. 9 is a diagram showing a separation process of a non-image portion.

FIG. 10 is a diagram showing a process of separating an image portion.

FIG. 11 is a diagram for explaining the significance of thinning the liquid developer.

FIG. 12 is a diagram showing a state in which a developing roller and a photoconductor are in hard contact.

FIG. 13 is a view for explaining soft contacts of the electrostatic latent image liquid developing device of the present invention.

14 is a schematic diagram of a developing device used in the liquid developing device for the electrostatic latent image shown in FIG.

15 is a diagram showing a modified example of the developing device used in the liquid developing device for the electrostatic latent image shown in FIG.

FIG. 16 is a schematic configuration diagram of a liquid developing device for an electrostatic latent image that is a second embodiment of the present invention.

FIG. 17 is a schematic diagram of a developing device used in the electrostatic latent image liquid developing device shown in FIG. 16.

FIG. 18 is a diagram showing a modified example of the developing device used in the liquid developing device for the electrostatic latent image shown in FIG. 16;

FIG. 19 is a schematic configuration diagram of a liquid developing device for an electrostatic latent image, which is a first aspect of a third embodiment of the present invention.

20 is a schematic diagram of a developing device used in the liquid developing device for the electrostatic latent image shown in FIG.

21 is a schematic diagram of a supply roller used in the developing device shown in FIG.

FIG. 22 is a schematic view of a developing device used in a liquid developing device for an electrostatic latent image, which is a second aspect of the third embodiment of the present invention.

FIG. 23 is a diagram showing a modified example of the developing device used for the electrostatic latent image liquid developing device according to the third aspect of the third embodiment of the present invention.

FIG. 24 is a schematic configuration diagram of a liquid developing device for an electrostatic latent image which is a first aspect of the fourth embodiment of the present invention.

FIG. 25 is a schematic configuration diagram of a liquid developing device for an electrostatic latent image which is a second aspect of the fourth embodiment of the present invention.

FIG. 26 is a schematic configuration diagram of a liquid developing device for an electrostatic latent image, which is a third aspect of the fourth embodiment of the present invention.

[Explanation of symbols]

1, 2, 3, 4, 5, 6 Liquid developing device for electrostatic latent image 10 Photoconductor 12 Photosensitive belt 20 Pre-wetting device 30 Charging device 40 Exposure device 50, 50a, 50b, 50c, 52, 52a, 52
b, 52c, 54b, 54c developing device 60, 60a transfer device 70 cleaning device 80 static eliminator 122a, 122b, 122c, 512a, 512b,
512c, 1512a, 1512b, 1512c, 25
12a, 2512b, 2512c, 3512a, 351
2b, 3512c, 3542a, 3542b, 3604
a, 3604b, 3604c drive roller 202 pre-wet liquid supply member 204 case 206, 502, 1502, 2502, 3502 tank 208 pump 210a, 210b tube 212 displacement device 220 pre-wet liquid 351, 353, 355 supply device 351a, 351b, 351c , 351d, 353a,
353b, 353c, 353d, 355a, 355b,
355c, 355d Developing cartridge 504 Layer forming blade 506 Developer supplying roller 508, 508a, 508b, 508c, 508d
Liquid developer 510, 1510, 2510, 3510, 3540
Developing belt 513 Holding plate 520, 2540 Developing roller 602 Transfer roller 604 Paper 702 Fixing roller 704 Fixing heater 1504, 2504, 3502a Supply roller 1505 Control blade 1506, 3506 Application roller 1514a, 1514b, 2522, 3504 Conveying roller 1516a, 1516b Adjusting roller 1517, 2514, 3514 Scraping blade 1519 Scraping roller 2506 Refresh roller 3509 Rotating shaft 3529 Cam 3544a, 3544b, 3544c, 3544d
Separation roller 3602 Intermediate transfer belt 3603 Secondary transfer roller 3605a, 3605b Holding roller 3606 Corona discharger

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Nakagoshi 2-6-3 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Steel Corporation

Claims (15)

[Claims] 1. An electrostatic latent image formed on an image support,
A liquid developing device for an electrostatic latent image, which is developed by a toner which is a charged image-forming particle, having a viscosity of 100 to 10000 mPa · s in which a toner is dispersed in a high density in a developer support. Coating means for applying a liquid developer to the surface of the developer support in a thickness of 5 to 40 μm, and supplying the liquid developer to the surface of the image support through the developer support. A liquid developing device for an electrostatic latent image, comprising a developing means. 2. The electrostatic latent image liquid developing device according to claim 1, wherein the coating means includes a layer forming blade provided so as to contact the developer support in the trail direction. . 3. The electrostatic latent image according to claim 2, wherein the layer forming blade is provided so that its tip projects by 10 to 100 μm from the contact position with the developer support. Liquid developing device. 4. The electrostatic latent image according to claim 2, wherein the layer forming blade is formed of an elastic member that does not swell in the insulating liquid used for the high-viscosity liquid developer. Liquid developing device. 5. The coating means coats the high-viscosity liquid developer on the surface of the developer support through at least two rollers.
The electrostatic latent image liquid developing device described. 6. The coating means comprises at least one adjusting roller for adjusting the liquid amount of the liquid developer attached to the roller, which is in contact with any one of the at least two rollers. Item 5. A liquid developing device for an electrostatic latent image according to item 5. 7. The electrostatic latent image liquid developing device according to claim 1, wherein the coating means includes a roller whose surface is covered with sponge. 8. The roller has a sponge thickness of 1
The liquid developing device for an electrostatic latent image according to claim 7, wherein the liquid developing device has a thickness of about 4 mm. 9. The applying means comprises a refreshing roller pressed by the roller to squeeze out the high-viscosity liquid developer held by the roller and to cause the roller to absorb the high-viscosity liquid developer. 9. The liquid developing device for an electrostatic latent image according to claim 7, wherein: 10. A pre-wetting means for applying a pre-wetting liquid, which is a dielectric liquid having releasability and chemically inert, onto the image support. 2. A liquid developing device for an electrostatic latent image according to 2, 3, 4, 5, 6, 7, 8 or 9. 11. The pre-wetting liquid has a viscosity of 0.5.
To 5 MPa · s, electric resistance 10 ¹² [Omega] cm or more, a boiling point of 100 to 250 ° C., the liquid developing device of an electrostatic latent image according to claim 10, wherein the surface tension is less than 21dyn / cm. 12. The pre-wetting liquid contains silicon oil as a main component.
2. The electrostatic latent image liquid developing device according to 2. 13. The liquid developer, wherein the insulating liquid has a viscosity of 0.5 to 1000 mPa · s and an electric resistance of 10 ¹² Ωc.
m or more, surface tension 21 dyn / cm or less, boiling point 10
It is 0 degreeC or more, The claim 1, 2, 3,
4, 5, 6, 7, 8, 9, 10, 11 or 12, the electrostatic latent image liquid developing device. 14. The electrostatic latent image liquid developing apparatus according to claim 13, wherein the liquid developer uses silicon oil as an insulating liquid. 15. The liquid developer has an average particle size of 0.1 to 0.1.
5. A toner containing 5 .mu.m at a concentration of 5 to 40%, wherein the toner is 5 to 40%.
8. A liquid developing device for an electrostatic latent image according to 8, 9, 10, 11, 12, 13 or 14.