WO1995018993A1

WO1995018993A1 - Liquid developing method of electrostatic latent image and liquid developing apparatus

Info

Publication number: WO1995018993A1
Application number: PCT/JP1995/000012
Authority: WO
Inventors: Tsutomu Sasaki; Masahiko Itaya
Original assignee: Nippon Steel Corporation
Priority date: 1994-01-10
Filing date: 1995-01-10
Publication date: 1995-07-13
Also published as: DE69526499T2; EP0760494B1; EP0760494A4; ATE216785T1; DE69526499D1; EP0760494A1

Abstract

This invention relates to a liquid developing method of an electrostatic latent image and a liquid developing apparatus which can prevent distortion of an image due to adhesion of toner to a non-image portion of an image supporter. The developing method includes the step of applying a pre-wet solution to a photosensitive member (10), and the development step of forming a thin layer of a liquid developer having a high viscosity and prepared by dispersing toner with a high concentration in an insulating liquid, on a developing roller (506) having flexibility, and bringing the liquid developer layer on the developing roller (506) into contact with the pre-wet liquid layer on the photosensitive member (10) while rotating the developing roller (506) so as to supply the liquid developer to the latent image surface of the photosensitive member (10), thereby developing the electrostatic latent image formed on the photosensitive layer (10) by the toner.

Description

Description: Liquid developing method and liquid developing apparatus for electrostatic latent image

The present invention relates to a liquid developing method for an electrostatic latent image formed by using a liquid developer to form an electrostatic latent image formed by a method such as electrophotography, electrostatic recording, or ionography, and a liquid developing method. It concerns the equipment. Background art

2. Description of the Related Art Conventionally, in an electrostatic latent image liquid developing device that develops an electrostatic latent image formed on an image support with toner, which is a charged developing particle, the electrostatic latent image is formed on the latent image surface of the image support. As a method of supplying the liquid developer, a method of providing irregularities on the surface of a developing roller as a developer support, supplying the liquid developer to the image support while holding the liquid developer in the recesses, and a method of supplying a liquid to the image support. A method of supplying the liquid developer absorbed by the sponge roller to the image support by pressing the sponge roller against the image support using a diroller, wherein the liquid developer is stored. For example, a method of directly supplying a liquid developer to an image support without using the developer support by immersing the image support in a developer tank is used.

By the way, in a conventional electrostatic recording apparatus and the like, toner is generally applied to an organic solvent, Isopar G (registered trademark: manufactured by Exxon). A low-viscosity liquid developer mixed at a ratio of about 1-2% is used. However, in order to realize a safer and smaller liquid developing device by suppressing the generation of solvent vapor, it is necessary to use a liquid developer having a higher concentration than the liquid developer used in the conventional device. However, such a device has not been found in the past. Therefore, a high-concentration and high-viscosity liquid developer (toner in an insulating liquid with a high concentration of 100-10000 OmPa · s), it is not clear which method is suitable for supplying the liquid developer to the latent image surface of the image support. Disclosure of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid developing method for an electrostatic latent image using a high-density and high-viscosity liquid developer capable of preventing toner from adhering to a non-image portion on an image support and disturbing an image. And a liquid developing device.

The liquid developing method for an electrostatic latent image according to the present invention is a liquid developing method for an electrostatic latent image formed by developing an electrostatic latent image formed on an image support with toner, which is charged visualized particles. A thin layer of a high-viscosity liquid developer in which toner is dispersed at a high concentration in an insulating liquid is formed on a columnar developer support having elasticity. By contacting the liquid developer layer on the developer support with the image support while rotating the image support in the direction to follow the image support, the latent image on the image support is obtained. A developing step of supplying a liquid developer to the surface. The viscosity of the liquid developer is 100 to 1000 mPas, and the thickness of the liquid developer layer on the developer support is 5 to 40 m. Is desirable. The hardness of the developer support is preferably 5 to 60 degrees JIS-A.

In addition, an outer diameter slightly smaller than the outer diameter of the developer support is provided on both sides of the developer support, and the roller is brought into contact with the image support. It is desirable to adjust the pressing force of the image support on the image support.

Further, it is desirable that at least the surface of the developer support is formed of a conductive member that does not absorb the liquid developing agent.

Further, the developer support may have a foam inside.

In addition, the liquid developing method for an electrostatic latent image according to the present invention, prior to the developing step, comprises a pre-released, chemically inert dielectric liquid on an image support. It is desirable to have a preset process for applying a solution.

In the liquid developing method for an electrostatic latent image according to the present invention, the liquid developer layer on the developer support, the image support and the liquid developer layer on the developer support are rotated while rotating the cylindrical developer support having elasticity in a direction following the image support. By contacting the developer support, the developer support is elastically deformed in the developing area, so that the contact pressure when the liquid developer layer on the developer support and the image support come into contact with each other Distributed It can be done. As a result, it is possible to prevent the liquid developer layer on the developer support from being excessively crushed in the development area, thereby preventing toner from adhering to a non-image portion on the image support and disturbing the image. You. In addition, the toner is developed in a thin layer of the liquid developer in which the toner is dispersed at a high concentration, so that the amount of the liquid is much smaller than that of the conventional low-concentration liquid developer. You can do it. When the viscosity of the liquid developer is more than 1000 mPa · s, it becomes difficult to stir the insulating liquid and the toner, and how to use the liquid developer The problem is how to make it. As a result, the liquid developer of 100 000 mPa · s or more is not cost-effective and is not realistic. On the other hand, when the toner concentration is lower than 100 mPa's, the toner concentration decreases and the toner dispersibility deteriorates, so that it is not possible to develop the developer in a thin layer. Become. The layer thickness of the liquid developer must be thin when the toner concentration is high, and thick when the toner concentration is low. Also, the higher the viscosity, the thinner it needs to be. However, if the layer thickness is more than 40 / m, excessive toner adheres and image noise occurs. On the other hand, if the layer thickness is less than 5 m, unevenness will occur when an image of the solid portion is output. If the hardness of the developer support is less than 5 degrees JIS-A, it is difficult to maintain a constant shape because it is too soft. On the other hand, if the hardness is 60 degrees JIS-A or more, the liquid developer layer is too hard, so that the liquid developer layer on the developer support and the image support are not excessively crushed. To make contact, the developer support and the image The developer support must be installed so as to form a minute gap or gap between the support and the developer. This makes it difficult to install a developer support.

In addition, an outer diameter slightly smaller than the outer diameter of the developer support is provided on both sides of the developer support, and the roller is brought into contact with the image support to thereby provide the developer support. In the case of adjusting the pressure contact force on the image support, the contact pressure when the liquid developer layer on the developer support comes into contact with the image support can be easily adjusted.

When at least the surface of the developer support is formed of a conductive member that does not absorb the liquid developer, the liquid developer layer on the developer support comes into contact with the image support to develop the image. When the developer support undergoes elastic deformation, it is possible to prevent the developer support from absorbing and releasing the liquid developer and disturbing the liquid developer layer.

Further, when a material having a foam inside is used as the developer support, a developer support having a desired value of hardness can be relatively easily obtained.

In addition, in the case where a pre-press step of applying a pre-release liquid, which is a releasable and chemically inert dielectric liquid, is provided prior to the development step, In the present invention, since a developer support having elasticity is used, two layers of a liquid developer layer on the developer support and a pre-jet liquid layer on the image support are used in the development area. Contact can be made while maintaining the state. For this reason, the liquid developer layer is Since the toner comes into contact with the surface of the image support through the nip, toner can be more effectively prevented from adhering to a non-image portion on the image support and disturbing the image.

In addition, the viscosity of the plug solution is 0.5 to 5 mPa · s, the electric resistance is more than ^{10 12} Ωcm, the boiling point is 100 to 250 ° C, and the surface is When the tension is 21 dyn Z cm or less, it is possible to obtain a pre-set liquid having releasability and good insulating properties. The split solution is absorbed by paper or the like at the time of transfer, and therefore needs to be evaporated at the time of fixing. For this reason, the viscosity is desirably 0.5 to 5 mPa * s in order to easily evaporate. If the viscosity is 5 mPas or more, it will be difficult to evaporate, and if it is 0.5 mPas or less, the volatility will be high. Not suitable. If the boiling point is lower than 100 ° C, the amount of evaporation increases, and there is a problem in the storage method of the plumb solution.The entire device must be sealed and the work required. It will also be difficult to improve the 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 a high cost. When the electrical resistance is less than or equal to 1 0 ^'2 Ω cm, the insulating Ri is poor, and it becomes rather unable used as a Prin c or falling edge of door solution. Therefore, it is desirable that the electric resistance value be as high as possible. When the surface tension is 21 dyn cm or more, the wettability deteriorates, and the familiarity with the liquid developer deteriorates. Therefore, it is desirable that the surface tension be as low as possible. The liquid developing method of the electrostatic latent image of the present invention, viscosity Doryokuku 0 of the insulating liquid. 5 ~ 1 0 0 O m P a · s, electric resistance 1 0 ^{1 2} Omega cm or more, a surface tension of 2 When a liquid developer having a boiling point of 1 ° dyn Z cm or less and a boiling point of 100 ° C. or more is used, a high-viscosity liquid developer can be obtained. Since the liquid developer layer formed on the developer support is formed in a thin layer, the amount of insulating liquid contained in the liquid developer layer is extremely small, and is supplied to the latent image surface of the image support. The amount of insulating liquid contained in the liquid developer is very small. Therefore, the amount of insulating liquid absorbed by paper or the like at the time of transfer is extremely small, and if the viscosity is 100 mPas or less, the problem of adhesion of the insulating liquid to paper or the like is particularly problematic. I do not. However, if the viscosity is less than 0.5 mPa * s, the volatility increases and it is not suitable because it is treated as dangerous goods. If the insulating liquid has a boiling point of less than 100 ° C, the amount of evaporation increases, so there is a problem in the method of storing the developer, and the entire device must be sealed. It will also be difficult to improve the environment. If the electrical resistance is below 1 0 ^'2 Ω cm, the insulating Ri is Do rather poor, bets Na primary conductive issues as a developer becomes rather unable use Ri Oko. Therefore, the electric resistance should be as high as possible. If the surface tension is more than 21 dyn Z cm, the leakage will be poor, and the familiarity with the pre-wiring solution will be poor. Therefore, it is desirable that the surface tension be as low as possible.

If the liquid developer contains toner with an average particle size of 0.1 to 5 jtzm at a concentration of 5 to 40%, the Thus, a liquid developer in which toner is dispersed at a high concentration can be obtained. Also, the resolution is improved in inverse proportion to the toner particle size. Usually, the toner is present as a mass of about 5 to 10 pieces on the printed out paper, so if the toner has an average particle size of 5 zm or more, The resolution is degraded. On the other hand, when the average particle diameter of the toner is less than 0.1 ^ m, the physical adhesive strength increases, and it becomes difficult to peel off the toner during transfer. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic configuration diagram of an electrostatic latent image liquid developing apparatus according to a first embodiment of the present invention.

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

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

FIG. 4 is a diagram for explaining the operation of the plenum unit shown in FIG.

FIG. 5 is a diagram for explaining the flow of the pre-jet liquid when the pre-jet liquid supply body contacts the photoconductor.

FIG. 6 is a diagram for explaining the entire development process. Fig. 7 is a diagram showing the approach process.

FIG. 8 is a diagram showing a state of the toner moving process. FIG. 9 is a diagram illustrating a separation process of a non-image portion.

FIG. 10 is a diagram showing the separation process of the image part. 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 contacted with a hard disk.

FIG. 13 is a diagram for explaining a soft contact used in the method of the present invention.

FIG. 14 is a diagram showing a modified example of the preset device shown in FIG.

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

FIG. 16 is a schematic diagram of a developing port used in the developing device shown in FIG.

FIG. 17 is a diagram for explaining a method of abutting the photoconductor and the developing roller.

FIG. 18 is a diagram showing a modification of the developing device shown in FIG.

FIG. 19 is a diagram showing another modification of the developing device shown in FIG.

FIG. 20 is a schematic configuration diagram of a liquid developing device for an electrostatic latent image according to a second embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a liquid development of an electrostatic latent image according to a first embodiment of the present invention. FIG. 2 is a schematic perspective view of a printer used in the electrostatic latent image liquid developing apparatus shown in FIG. 1, and FIG. 2 is a schematic perspective view of the electrostatic latent image liquid developing apparatus shown in FIG. FIG. 4 is a diagram for explaining the operation of the apparatus, FIG. 4 is a diagram for explaining the operation of the plotting device shown in FIG. 2, and FIG. Fig. 15 shows the flow of the splitting liquid when it comes into contact with the developer. Fig. 15 is a schematic diagram of the developing device used in the electrostatic latent image liquid developing device shown in Fig. 1, and Fig. 16 is the diagram. FIG. 15 is a schematic diagram of a developing roller used in the developing device shown in FIG. 15, and FIG. 17 is a view for explaining a method of contacting the photosensitive member with the developing roller.

As shown in FIG. 1, a liquid developing apparatus for an electrostatic latent image according to a first embodiment of the present invention includes a photosensitive member 10 serving as an image support, and a printer on a photosensitive member 10. A liquid jet printer 20 for applying the liquid, a charging device 30 for charging the photoreceptor 10, an exposure device 40 for exposing an image on the photoreceptor 10, and a photoreceptor 10. Developing device 50 that visualizes the electrostatic latent image by supplying toner to the portion where the electrostatic latent image is formed, and transfers toner on photoreceptor 10 to predetermined paper The apparatus includes a transfer device 60 and a cleaning device 70 for removing toner adhered on the photoconductor 10.

For the charging device 30, the exposure device 40, the transfer device 60, and the cleaning device 70, the conventional technology used for the conventional electrophotographic printer can be used in most cases. it can. Therefore, in the present embodiment, the description of each device described above is omitted, and the pre- The cutting device 20 and the developing device 50 will be described.

As shown in FIG. 2, the printing apparatus 20 according to the present embodiment has a plate-shaped printing apparatus having a length substantially equal to an image width drawn on the photoconductor 10. A liquid supply body 202, a case 204 for accommodating the pre-wet liquid supply body 202, a tank 206 for storing the pre-wet liquid 220, and a tank 2 The pump is provided with a pump 208 for pumping the split liquid 220 stored in the tube 06, tubes 210 a and 21 Ob, and a displacement device 212.

The pipette liquid supply body 202 includes a continuous porous body having a cubic network structure in which pores are continuous, such as Beluis

(Registered trademark: Kanebo Co., Ltd.) is used. At night, it is possible to hold the preset liquid 220 by the volume of the pores, and when the preset liquid 220 that exceeds the pore volume is supplied, The split liquid 220 can be uniformly discharged in a direction perpendicular to the flow direction of the split liquid 220. On the surface of the case 204 facing the photoconductor 10, as shown in FIG. 4, the bottom surface of the split liquid supply body 202 can be brought into contact with the photoconductor 10. Opening 204a is provided so that The tube 210a transports the pre-jet liquid 220 pumped by the pump 208 to the supply side 202a of the pre-jet liquid supply body 202. I do. A space 204 b is formed between the supply side 202 a of the plumbing liquid supply body 202 and the case 204. 2 2 0 is this space After being stored in section 204b, it is supplied from supply side 202a. The tube 21Ob transports the pipette liquid 220 released from the discharge side 202b of the pipette liquid supply body 202 to the tank 206. I do. When no signal is input from the outside, the displacement device 2 1 2, as shown in FIG. When a signal is input from the outside while being held at a remote position, as shown in FIG. 4 (B), the split liquid supply member 202 is brought into contact with the photosensitive member 10. .

As shown in FIG. 15, the developing device 50 of this embodiment includes a bellows pump 502 and a bellows pump 502 that store and discharge a high-concentration and high-viscosity liquid developer 508 described later. A liquid reservoir 504 for storing the liquid developer 508 discharged by the pump 502 and a lower portion provided to be immersed in the liquid developer 508 stored in the liquid reservoir 504. The developing roller 506 as a developer support, the regulating roller 510 formed of an elastic member for adjusting the layer thickness of the liquid developer 508, and the developing port 506 And a removal blade 512 for removing the attached liquid developer 508.

The developing roller 506 has substantially the same length as the width of the image drawn on the photoreceptor 10 and is formed of a rigid body such as stainless steel as shown in FIG. A core metal 506a, an elastic cylindrical body 506b formed around the core metal 506a, and a surface layer 506c formed on the surface of the cylindrical body 506b. Having. Elastic member forming cylindrical body 5 06 b For example, foams such as polystyrene, polyethylene, polyurethan polyvinyl chloride, and NBR (Nitrino 'butylene' lanokuichi), Alternatively, there is a low-hardness rubber member such as silicone rubber or urethane rubber. However, if a rubber member is used for many years in a state where it is generally elastically deformed, it may be permanently deformed and may not return to its original shape, that is, a columnar shape. For this reason, it is preferable to use a foam, if possible, for the elastic member forming the cylindrical body 506b. The surface layer 506 c is formed of a conductive material that does not swell in silicon oil, which is a carrier liquid of the liquid developer 508 described later.The electric resistance of the conductive member is to cormorants by Ru can apply a developing roller 5 0 6 two electrical developing bias, 1 0 ³ Ω cm about a is this and is desired arbitrary. As a method of forming the surface layer 506c on the surface of the cylindrical body 506b, for example, a method in which conductive particles such as carbon black are dispersed on the surface of the cylindrical body 506b is used. There is a method of coating the rubber-based composite, a method of covering the cylindrical body 506b with a conductive heat-shrinkable tube, and applying heat to the heat-shrinkable tube. A cylindrical body 506 b may be formed inside the surface layer 506 c by injecting an elastic material into the inside of the tube, or by foaming the injected elastic material. . As the conductive tube, a resin tube such as polyimid, polycarbonate, and nylon, and a metal tube such as nickel are used. Examples of conductive heat-shrinkable tubes include PFA and PTFE. A resin tube is used. It is desirable that these tubes be seamless endless tubes. When the cylinder 506 is made of an elastic member such as urethane rubber which does not swell in silicone oil, the surface layer 506 is formed on the surface of the cylinder 506 b. There is no need to form c. However, in order to apply an electric developing bias to the developing roller 506, the surface of the cylindrical body 506b is conductively processed or elastically formed to form the cylindrical body 506b. such as by adding conductive fine particles to the member, there electric resistance value desired value, i.e., needs to be about 1 0 ³ Ω cm.

Further, as shown in FIG. 15, the developing roller 506 is disposed so as to abut the photosensitive body 10, and is arranged in a direction opposite to the rotation direction of the photosensitive body 10, that is, It rotates in the direction that follows the body 10. Thus, the liquid developer 508 stored in the liquid reservoir 504 is pumped up and transported to the surface of the photoconductor 10. As shown in FIG. 15, the developing roller 506 has a nip width in the developing area due to elastic deformation generated by the pressing force of the developing roller 506 against the photoconductor 10. t is formed. The hardness of the developing roller 506 is preferably 5 to 60 degrees JIS-A. If the hardness is less than 5 degrees JIS-1A, it is too soft to maintain a certain shape. On the other hand, if the hardness is more than 60 degrees JIS-A, the liquid developer layer on the developing roller 506 and the pre-jet liquid layer on the photoreceptor 10 are in a two-layer state because it is too hard. To maintain contact while maintaining the developing roller 506 and the photoconductor It is necessary to install the developing roller 506 so as to accurately form a minute gap, that is, a gap between the developing roller 506 and the developing roller 506. Therefore, it is difficult to install the developing roller 506. The nip width t generated by the elastic deformation of the developing roller 506 is determined by an electric circuit including a capacitance and a resistance component formed by the developing roller, the developer layer, and the photoconductor. It is set in relation to the development time constant specified by The adjustment of the pressing force of the developing roller 506 to the photoconductor 10 is performed by adjusting the pressing force on both sides of the developing roller 506 as shown in FIGS. 17 (A) and (B). The contact patch 507 was placed in contact with 10 and the contact patch 507 was replaced with one with a different outer diameter. The outer diameter of the contact roller 507 is selected to be smaller than the outer diameter of the developing roller 506 and larger than the compression limit of the developing roller.

The regulating roller 510 is provided so as to contact the developing roller 506, and rotates in a direction opposite to the rotation direction of the developing roller 506. As a result, the thickness of the liquid developer 508 on the developing roller 506 is regulated to form a thin liquid developer layer on the developing roller 506. In experiments conducted by the present inventors, good results were obtained when the peripheral speed of the regulating roller 510 was about twice the peripheral speed of the developing roller 506.

Next, an image forming material used in this embodiment will be described. The liquid developer 508 used in the present embodiment uniformly disperses a resin serving as a binder such as an epoxy, a charge control agent that gives a predetermined charge to the toner, a coloring pigment, and the toner. It consists of a toner composed of a dispersant and the like, and a carrier liquid. The configuration of the toner is basically the same as that used in conventional liquid developers, but their formulations are compatible with silicone oil to adjust charging characteristics and dispersibility. It has been changed. The smaller the average particle size of the toner, the better the resolution. However, the smaller the particle size, the greater the physical adhesive strength and the more difficult it is to peel off when transferring. For this reason, in the present embodiment, the average particle diameter of the toner is adjusted so that the center comes around 2 to 4 m for the purpose of improving the transferability.

The viscosity of the liquid developer depends on the carrier liquid, resin, coloring pigment, charge control agent, etc. used, and their concentration. In this example, the experiment was performed by changing the viscosity in the range of 50 to 600 OmPas and the toner concentration in the range of 5 to 40%. As the carrier liquid, a liquid having a low viscosity such as dimethylpolysiloxane oil or cyclic polysiloxane oil having high electric resistance is used. Since the liquid developer layer formed on the developer support is formed in a thin layer, the amount of carrier liquid contained in the liquid developer layer is extremely small, so that the latent image on the image support is The carrier liquid contained in the liquid developer supplied to the image surface is also very small. Therefore, the amount of carrier liquid absorbed by paper or the like at the time of transfer is extremely small. If the viscosity is 100 mPas or less, the carrier remaining on paper or the like after fixing is obtained. Liquid is hardly seen. According to experiments conducted by the present inventors and others, the carrier liquid has a viscosity of 2.5 mPa · s from Dow Corning, Inc. When an image-drawing experiment was performed using Dow Corning's DC345, which has a high viscosity and a high viscosity of 6.5 mPa · s, the carrier remaining on the paper after fixing was used. No liquid was seen, but because of its high volatility, it was necessary to make the developing unit a hermetically sealed structure. In addition, when a printing experiment was performed using Shin-Etsu Silicon KF-96-20, which has a carrier liquid viscosity of 20 mPa · s, it was printed on paper after fixing. No carrier liquid was found in the sample. In addition, since the volatility is not so high, there was no need to make the developing device a hermetically sealed structure. DC 344, DC 345 and KF-966-20 are generally used for cosmetics. The safety of toxicity is high. There are many other types of carrier liquid, such as Shin-Etsu Silicone's KF 9337, provided that the electrical resistance, evaporation characteristics, surface tension, safety, etc. are satisfied. Either can be selected.

Further, according to the experiments by the inventors, when the surface tension is large, fogging and toner clumps may adhere, and when the surface tension is 21 dyn cm or more experimentally, It turns out that problems are likely to occur in image quality.

Is the electrical resistivity, Ri charging stability problems exist bets toner, 1 0 ^'4 Ω cm or desired arbitrary. Minimum ¹ 0 1 ² Ω cm or more is required. In the description of the present embodiment, in view of these experimental results, an example using DC345, which is low in price and easily available, will be described.

The Plut solution is an electrostatic latent formed on the image support. It is required that the toner does not disturb the image, easily evaporates at the time of fixing, and does not adhere to the fog toner. For example, DC344, DC200—0.65, —1.0, —2.0 from Dow Corning, USA, and KF96L—1, KF from Shin-Etsu Silicon. 9 9 3 7 and so on. Generally, it is preferable to select silicone oil which has a high evaporation rate.

In experiments conducted by the inventors, the liquid was dried by development, transfer, and fixing without any problem when the liquid viscosity was in the range of 0.5 to 3 mPas. From s to about 6 mPa · s, it tended to require time and temperature to dry the solution at the time of fixing. At 1 O m P a · s, the energy required for drying is too large and is not common. In addition, if it is less than 0.5 mPa · s, the volatility will be high, so it is not suitable because it is treated as dangerous goods and subject to laws and regulations. Also, due to the effect of heating the paper, the boiling point is preferably 250 ° C or less.

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 being stained, and improve the resolution of image quality. According to experiments performed by the present inventors, it is preferable to select a material having a limit of about 20 to 21 dynZcm, which is lower than the limit.

If the electrical resistance is low, it leaks the latent image charge and blurs the image. Therefore, it is necessary to use one with as high an electric resistance as possible. Arbitrary desired 1 0 ^'4 Ω cm about than the experimentally. Minimum 1 0 ^'2 Ω cm is necessary. Next, the operation of the electrostatic latent image liquid developing apparatus according to the present embodiment will be described. First, as shown in FIG. 3 (A), the above-mentioned split solution 220 is applied to the photoreceptor 10 by the split device 20. When a control signal is input from the outside, the presetting device 20 brings the preset liquid supply member 202 into contact with the photosensitive member 10. The pump liquid 208 constantly circulates the preset liquid 220 inside the split liquid supply unit 202, and the preset liquid supply unit As shown in FIG. 5, the plunger liquid 220 exceeding the volume of the pores at Verui overnight, which is 202, is discharged from the plunger liquid supply body 202 as shown in FIG. It is released from the bottom of the pre-jet liquid supply body 202 together with the release from the 202 b, and is uniformly applied on the photoreceptor 10 without damaging the photoreceptor 10 .

Next, as shown in FIG. 3 (B), the photoreceptor 10 coated with the plating solution 220 is charged by a corona discharger 302. The charges carried by the ions pass through the pre-wet liquid layer and reach the surface of the photoconductor 10. Next, an image is exposed on the charged photoconductor 10. For example, an image is exposed by a laser scanner to form an electrostatic latent image on the surface of the photoconductor 10. As shown in Fig. 3 (C), the part exposed to the light from the laser scanner becomes conductive and loses the charge, and the part not exposed to the light is an electrostatic latent image, which is an image of the charge. And remain.

Next, the electrostatic latent image is visualized by the developing device 50. Released by bellows pump 502 and stored in reservoir 504 After the liquid developer 508 is pumped up by the developing roller 506, the layer thickness is adjusted by the regulating roller 510 to form a thin layer on the developing roller 506. . The liquid developer layer formed on the developing roller 506 in this manner is brought close to the electrostatic latent image formed on the surface of the photoreceptor 10 as shown in FIG. 3 (D). The charged toner is moved to the photoconductor 10 by the electrostatic force. The liquid developer 508 stored in the liquid reservoir 504 is agitated by the rotation of the developing roller 506.

Next, as shown in FIG. 3 (E), the toner image on the photoreceptor 10 is transferred to a predetermined paper by an electrostatic force generated by a voltage applied to the transfer roller 602 of the transfer device 60. Transfer to 6 4. Although not shown in FIG. 1, as shown in FIG. 3 (F), paper is fixed by a fixing heater 704 provided in a fixing roller 720 of the fixing device. The toner transferred to 604 is melted thermally and fixed on paper. On the other hand, the liquid developer 508 remaining on the photoreceptor 10 is removed by the cleaning device 70. After the photoconductor 10 is neutralized by a neutralization device (not shown), the photoconductor 10 is used again in the cycle from the above-described process to the neutralization.

6 to 10 are views for explaining the development process of this embodiment in detail, FIG. 6 is a diagram for explaining the entire development process, and FIG. 7 is a view showing the approach process. Fig. 8 is a diagram showing the toner movement process, Fig. 9 is a diagram showing the separation process of the non-image portion, and Fig. 10 is a diagram showing the separation process of the image portion. It is. Unlike the conventional developing process, as shown in FIG. 6, the developing process of this embodiment includes an approaching process in which the developing roller approaches the photoconductor and the liquid developer approaches the photoconductor surface, and a liquid developing process. The toner moving process in which the toner layer moves by the contact between the developer layer and the pre-coating liquid layer, and the toner and the photosensitive drum that separate the developing roller from the photoconductor and adhere to the developing roller It is thought to consist of three processes: the toner that adheres to the body and the separation process that separates the toner.

In the approaching process, as shown in FIG. 7, by using an elastic developing roller 506, the liquid developer layer on the developing roller 506 and the pre-press on the photoreceptor 10 are used.接触 The contact pressure at the time of contact with the jet liquid layer is dispersed, and the high-viscosity liquid developer composed of the carrier liquid and the toner and the jet liquid are applied to the software. It is cut. At this time, as if a minute gap, that is, a gap d, was formed between the developing roller 506 and the photoreceptor 10 via the liquid developer layer and the pre-coat liquid layer. Become. Note that, in the toner transfer process, as shown in Fig. 8, the low-viscosity plunger liquid is slightly pushed out before and after the plunger liquid pools. The latent image passes through the liquid preyet liquid layer mainly by a coupler due to an electric field formed between the charge on the photoreceptor 10 and the developing roller 506. Move to the plane. On the other hand, the toner in the non-image area is basically an unnecessary toner because the surface of the photoreceptor 10 and the liquid developer layer are separated by the pre-wet liquid layer. Adhesion to the surface of photoconductor 10 No.

In the separation process, in the non-image area, the liquid developer basically remains on the developing roller 506 as shown in FIG. At the interface between the split liquid layer and the liquid developer layer, when the two layers separate, part of the low-viscosity pellet liquid layer transfers to the liquid developer layer and separates . Therefore, the separation point between the two layers is considered to be inside the prewet liquid layer. On the other hand, in the image area, the toner that has moved to the surface of the photoreceptor 10 pushes out the pre-wet liquid layer as shown in FIG. Located above the toner layer and separates within that layer. On the developing roller 506, a layer is formed by a part of the carrier liquid and a part of the pulp liquid remaining after the toner moves. The pre-jet liquid remaining on the photoreceptor 10 facilitates the transfer by the electrostatic force of the toner in a 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 roller 506 is too thick, the viscosity of the liquid developer 508 is high, and the liquid developer 508 moves from the developing roller 506 to the surface of the photoreceptor 10 by electrostatic force. The toner group to be formed forms a cluster without breaking the viscosity with respect to the toner located therearound and moves to the surface of the photoreceptor 10, so that excessive toner adheres. And image noise occurs. In order to suppress the occurrence of this cluster, it is necessary to keep the liquid developer layer thickness at a minimum value that allows sufficient development. FIG. 12 is a diagram showing a state in which a developer support and a photoconductor are contacted to a hard, and FIG. 13 is a diagram illustrating a soft contact of the present embodiment. FIG. As described above, in the development process of this embodiment, the function of the pre-press liquid layer for image formation is important. Therefore, an important requirement in the development process is to maintain the state of the two layers of the plotting liquid layer and the liquid developer layer. As shown in FIG. 12, when the developer support and the photoreceptor are hard-contacted, the state of two layers cannot be maintained. In the present embodiment, as shown in FIG. 13, an elastic developing roller 506 is used as a developer support, so that the photosensitive member 1 of the developing roller 506 is used. By adjusting the pressing force to 0 to disperse the contact pressure when the liquid developer layer on the developing roller 506 comes into contact with the pleated liquid layer on the photoconductor 10, It is as if a minute gap, that is, a gap d, was formed between the photoreceptor 10 and the developing roller 506 via the liquid developer layer and the pre-wet liquid layer. For this reason, the liquid developer layer and the split liquid layer can be brought into contact with each other in the developing area while maintaining a two-layer state in which the layers can be distinguished from each other. The optimization of the layer thickness of the pre-wet solution layer and the development gap, that is, the spacing, will be described. The thickness of the liquid developer layer should be thinner if the liquid developer has a viscosity of 500 to 100 mPas or more, especially if it has a viscosity of 500 mPas or more. There is. Ideally, the amount of toner development required during development (ie, Slightly better than the layer thickness that satisfies (the density when a large area is painted black). This is because when a liquid developer with a high viscosity is used, during development, the electrostatically selected toner moves onto the photoreceptor due to the excess toner due to the viscosity of the liquid. This causes abnormal toner adhesion, which causes image stains. In experiments conducted by the inventors, good images were obtained with a layer thickness of from 5 m for a developer having a high toner concentration and about 40 zm for a developer having a low toner concentration. When a developer having a toner concentration of 20 to 30% was used, good image quality was obtained when the toner layer thickness was about 8 to 20 zm.

There is an optimum value for the thickness of the pre-out liquid layer depending on the viscosity and surface tension of the selected pre-out liquid. If it is too thin, the high-viscosity liquid developer adheres irregularly on the photoreceptor, causing image stains. As the amount of the pre-wet solution is increased, the image stain is improved and the optimum value is confirmed. As the amount is further increased, the charge of the latent image tends to flow, resulting in a decrease in sharpness and resolution, and a toner flow during development, which also tends to blur the image. In the experiment using DC344, good results were obtained with a thickness of 30/111 or less, especially 20 /// 111 or less. For the less viscous ones, good results can be obtained with thinner and thicker ones. The optimum value tends to be narrower for high-viscosity materials such as stiffness, stiffness, etc.

The gap between the photoreceptor and the developing roller, that is, the gap, The narrower the image quality, the better the resolution and the uniformity of the solid part density in the image quality, as in the conventional developing method. The high-viscosity liquid developer used in the present embodiment has a strong cohesive force between toners, and, like a powder developer, generates a mechanical shock and an electrostatic force from a developer support or carrier particles. Thus, the phenomenon that the released toner is used for development does not occur. That is, no image is formed if an air layer is interposed between the liquid developer layer and the photoconductor. Therefore, it is essential that the developing roller and the liquid developer layer are in contact with each other, and the liquid developer layer and the pre-jet liquid layer are in contact with the photo-conductor. . Therefore, the developing gap, that is, the distance d, must be smaller than the thicknesses of the liquid developer layer and the pre-jet liquid layer and must not be disturbed by the respective layers. In the present embodiment, in accordance with the difference in the hardness of the developing roller 506, the viscosity of the developer, and the toner concentration, the liquid layer on the photosensitive member 10 and the developing roller 506 are changed. When the developing roller 506 is brought into contact with the liquid developer layer, the pressing force of the developing roller 506 against the photoreceptor 10 is adjusted so that the distance d is between 8 μm and 50 μm. Set.

Table 1 shows the results of the image extraction experiment performed under the above conditions. From these results, the optimum range of the viscosity of the developing agent and the pre-jet solution for the developing method of the present embodiment is 100 mPas. It was found that P a-s, the pre-split hydraulic power was 0.5 mPa · s, between 5 mPa · s. As for the image quality, the thickness of the liquid developer layer on the developing roller, the thickness of the pre-wet liquid layer, and the development Although it varies depending on the effects of gaps, etc., even if the development conditions are optimized, there is a tendency generally as shown in Table 1, and the optimal area of the liquid developer is shown in Table 1. It was confirmed that it was within the specified range. In addition, DC200 series manufactured by Dow Corning is used for silicone fluid of the pre-wet solution, and the company's carrier fluid for the developer is DC 345 was used.

table 1

According to the first embodiment of the present invention, the liquid developer layer on the developing roller 506 and the liquid developer layer on the photosensitive member 10 are rotated while rotating the developing roller 506 having elasticity in a direction following the photosensitive member 10. The developing roller 506 is elastically deformed in the developing area by contacting the pre-wet liquid layer with the liquid developer layer on the developing roller 506 and the photosensitive member. It is possible to disperse the contact pressure when the pre-jet liquid layer above 10 comes into contact. Therefore, in the developing area, the liquid developer layer And the split liquid layer can be brought into contact with each other while maintaining a two-layer state. Therefore, the liquid developer layer is excessively crushed, and the non-image area on the photoreceptor 10 is damaged. This prevents the image from being disturbed due to adhesion of the toner.

Further, according to the first embodiment of the present invention, the surface of the developing roller 506 is made of a conductive member which does not swell with silicone oil which is a carrier liquid of the liquid developer 508. By providing the formed surface layer 506c, when the developing port 506 is elastically deformed in the developing area, the liquid developer 508 absorbs and releases the liquid developer 508, and It is possible to prevent the prewetting liquid layer on the photoconductor 10 from being disturbed, thereby preventing the toner image formed on the photoconductor 10 from being disturbed. eo

Further, according to the first embodiment of the present invention, a contact roller 507 is provided on both sides of the developing roller 506 so as to be in contact with the photoreceptor 10, and an outer diameter of the contact roller 507 is provided. The liquid developer layer formed on the developing roller 506 and the photoconductor 10 were adjusted because the pressure of the developing roller 506 against the photoconductor 10 was adjusted. It is possible to easily disperse the contact pressure at the time of contact with the split liquid layer formed at the bottom.

Further, according to the first embodiment of the present invention, the use of silicone oil as the carrier liquid for the liquid developer has the following advantages over the conventional one. Having.

Conventional liquid developers are generally used as carrier liquids.

Isopar G (registered trademark: manufactured by Exxon) is used. this Isopar does not have as high a resistance value as silicone oil, so that if the toner concentration is increased, that is, if the distance between the particles is reduced, the chargeability of the toner deteriorates. Therefore, in the case of Isopar, the toner concentration is limited. On the other hand, the silicon oil used in the present embodiment has a sufficiently large resistance value, so that the toner concentration can be increased. In general, in the case of Isopar, the toner is in a good dispersion state, 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, silicon oil having a toner concentration of 1 to 2% does not have good dispersibility and precipitates soon. When the toner concentration is adjusted to 5 to 40%, it becomes a densely packed state and disperses stably. For this reason, in this embodiment, a high-viscosity liquid developer in which toner is dispersed at a high density is used. As a result, the amount of the developing solution can be significantly reduced as compared with the conventional low-concentration liquid developing agent, and the size of the apparatus can be reduced. Furthermore, since the liquid developer of this embodiment is a high-viscosity liquid, storage and handling are easier than conventional low-viscosity liquid developers and powder developers.

As described above, Isopar used in a conventional liquid developer has high volatility and emits a foul odor, which not only deteriorates the working environment but also causes pollution. On the other hand, the silicone oil used in this example is a safe liquid and odorless, as is clear from the fact that it is used for cosmetics. So, this embodiment According to the project, the working environment can be improved and there is no pollution problem.

In the first embodiment, the bellows pump 502 is used as the means for supplying the liquid developer 508 to the developing roller 506, but the present invention is not limited to this. It is not specified. For example, as shown in a developing device 52 shown in FIG. 18, the liquid developer 508 stored in the tank 522 is replaced with the liquid developer 508 stored in the tank 522. It may be supplied to the developing roller 506 by being pumped up using a double gear pump 524 arranged and immersed in the developing roller.

In the first embodiment, the regulating roller 510 is used to adjust the layer thickness of the liquid developer 508 applied on the developing roller 506 to form a thin layer. Although the present invention has been described, the present invention is not limited to this. For example, as shown in a developing device 54 shown in FIG. 19, a liquid developer 508 applied on a developing roller 506 using a regulating blade 542 formed of rubber or a rigid body is used. The layer thickness may be adjusted to form a thin layer. In the experiments conducted by the present inventors, the contact between the regulating blade 542 and the developing roller 506 was such that the regulating blade 542 contacted the trailing direction, and the leading end of the regulating blade 542 was regulated. By designing the blade 542 so as to protrude from the contact position between the developing roller 506 and the developing roller 506, it was possible to form a stable developing agent thin layer.

Further, in the first embodiment described above, the splitting device 2 In the above description, the charging device 30 charges the photoreceptor 10 after the pre-jet liquid 220 is applied on the photoreceptor 10 by using the charging device 30. It is not limited to this. The application of the splitting liquid 220 may be performed as long as it is performed prior to the developing step.

Next, a second embodiment of the present invention will be described with reference to FIG. 20. FIG. 20 is a schematic configuration diagram of an electrostatic latent image liquid developing apparatus according to a second embodiment of the present invention. Here, the reference numerals in the figure are the same as those in the first embodiment for those having the same functions.

As shown in FIG. 20, a liquid developing apparatus for an electrostatic latent image according to a second embodiment of the present invention includes a photosensitive member 10 serving as an image support, and a print cartridge on the photosensitive member 10. A liquid ejection device 20 for applying a liquid, a charging device 30 for charging the photoconductor 10, an exposure device 40 for exposing an image on the photoconductor 10, and a static device for the photoconductor 10. A developing device 55 that visualizes the electrostatic latent image by supplying toner to a portion where the electrostatic latent image is formed, and a toner on the photoreceptor 10 is transferred and fixed on a predetermined sheet of paper. A transfer device 65 for transferring predetermined paper to the transfer device 65, and a cleaning device 70 for removing toner remaining on the photoreceptor 10. And a static eliminator 80 for neutralizing the charged photoconductor 10.

The liquid developing device for an electrostatic latent image of the second embodiment is different from the liquid developing device of the first embodiment in that the developing device 55 and the transfer device 6 5. The other parts are the same as those in the first embodiment, or the conventional technology used in the conventional electrophotographic printer can be used in most cases. Therefore, in this embodiment, the developing device 55 and the transfer device 65 will be described in detail, and the description of the other portions will be omitted.

The developing device 55 of the second embodiment includes a developing roller 556 as a developer support, a supply device 56 for applying a liquid developer 508 to the developing roller 556, and a developing device. A removal blade 557 for removing the liquid developer 508 attached to the roller 556 is provided.

The supply device 56 has four developing cartridges 56 a, 56 b, 56 c, 56 d (hereinafter, also simply referred to as developing cartridges) attached to the rotating shaft 55 9. It is provided. Each of the image cartridges includes a tank 552 for storing a liquid developer 508, a supply roller 552a provided at an outlet of the tank 552, and a supply roller. Developing cartridge provided with a transfer roller 554 provided so as to contact the transfer roller 554 and an application roller 555 provided so as to contact the transfer roller 554. The liquid developer 508 a containing yellow toner is contained in the tank 552 of the cartridge 56 a and the liquid containing magenta toner is contained in the tank 552 of the developing cartridge 56 b. The developer 508 b is strong, and the liquid developer 508 c containing cyanogen toner is contained in the tank 55 2 of the developing cartridge 56 c and the developing cartridge. 5 6 d tank 5 5 2 Liquid developer 508 d containing the toner of the rack is stored respectively (hereinafter, the liquid developers 598 a to 508 d are simply referred to as liquid developers 508). The supply device 56 is configured to rotate the rotation shaft 559 to rotate and move the developing cartridge, so that the coating port of one of the developing cartridges 55 5 is in contact with the developing roller 5 5 6. As a result, a liquid developer 508 containing toner of a desired color is applied to the developing roller 556.

The supply roller 552 a supplies the liquid developer 508 to the transport roller 554 by rotating in a direction opposite to the rotation direction of the transport roller 554. The transport roller 555 rotates in a direction opposite to the rotation direction of the coating roller 555, so that the liquid supplied to the coating roller 555 by the supply roller 552a is supplied. The developer 508 is conveyed. The application roller 555 rotates in a direction opposite to the rotation direction of the developing roller 556, so that the liquid developer 5 conveyed by the conveying roller 554 on the surface of the developing roller 556. 0 8 is applied. The transport port used to supply the liquid developer 508 to the developing roller 556 uses the roller 554 and the application roller 555 because the toner in the liquid developer 508 is dispersed in high density. This is because a large amount of the developer is not required, and therefore, a small amount of the liquid developer needs to be applied to the surface of the developing roller 556 thinly and evenly. One or more transport rollers for transporting the liquid developer 508 may be provided between the transport roller 554 and the application port roller 555. The developing roller 556 supplies the liquid developing agent 508 to the latent image surface of the photoconductor 10 by rotating in the opposite direction to the rotation direction of the photoconductor 10. It should be noted that the developing roller 556 is provided with elasticity and conductivity in the same manner as the developing roller 506 of the first embodiment. The detailed description of the developing rollers 556 will be omitted.

The transfer device 65 of the second embodiment includes an intermediate transfer belt 652, which is an intermediate transfer member, and driving rollers 654a, 654b, and 655 for rotating the intermediate transfer belt 652. 4 c, holding rollers 65 5 a, 65 5 b for holding a part of the intermediate transfer belt 65 2 so as to contact the photoreceptor 10, and an intermediate transfer belt 65 2 Discharger 656 that charges the toner with a charge having a polarity opposite to that of the toner, and a secondary transfer roller 6 that is a secondary transfer member detachably attached to the intermediate transfer belt 652. 5 and 3.

The intermediate transfer belt 652 is rotated in the opposite direction to the rotation direction of the photoconductor 10 by drive rollers 654a, 654b, and 654c. The intermediate transfer belt 652 may include a metal belt such as a nickel-less seamless belt, a resin belt such as a polyimide film belt, or a rubber belt such as a PET film belt. A belt member having flexibility such as is used. This disperses the contact pressure when the toner image formed on the photoreceptor 10 comes into contact with the intermediate transfer belt 652. be able to. When a resin belt or rubber belt is used, the surface of the belt is conductively processed or the belt material is used. It is necessary to achieve a desired electric resistance value by adding conductive fine particles.

On the intermediate transfer belt 652, a surface layer having good releasability such as Teflon or silicon is formed. This is to reduce the physical adhesion of the toner to the intermediate transfer belt 652 and facilitate the transfer of the toner to the paper.

The secondary transfer roller 653 rotates in a direction opposite to the rotation direction of the intermediate transfer belt 652, so that the paper conveyed by the paper feeder 6110 is intermediate-transferred. Feed between belt 652 and secondary transfer roller 653. At this time, the secondary transfer roller 653 is pressed against the intermediate transfer belt 652 via the paper. A secondary transfer bias is applied to the secondary transfer roller 653 to transfer the toner image formed on the intermediate transfer member 652 to paper. Then, the toner image is fixed on the paper by a fixing device (not shown). A fixing heater is provided inside the driving roller 654a, and the toner on the intermediate transfer belt 652 is heated by heating the toner on the intermediate transfer belt 652. The image may be transferred to paper and fixed at the same time. The fixing heater may be provided inside both the driving roller 654a and the secondary transfer roller 653.

Next, the operation of the electrostatic latent image liquid developing apparatus according to the second embodiment of the present invention will be described.

In the liquid developing device for an electrostatic latent image of the present embodiment, first, the photoconductor 10 is charged by the charging device 30, and the image is exposed on the photoconductor 10 by the exposure device 40. After forming an electrostatic latent image, The ripple liquid 220 is applied to the surface of the photoreceptor 10 by the repelling device 20. Next, the electrostatic latent image formed on the photoreceptor 10 is visualized by the developing device 55. The liquid developer 508 stored in the tank 552 is supplied to the transport roller 554 by the supply roller 552a, and is supplied to the transport roller 554 by the transport port 554. After being conveyed to the coating roller 555, it is applied to the developing roller 556 by the coating roller 555. The liquid developer 508 conveyed to the developing roller 556 via the roller in this way is applied thinly and evenly to the developing roller 556, forming a thin layer on the developing roller 556. I do. The supply device 56 rotates the developing shaft by rotating the rotating shaft 559 to apply any one of the developing powers of the developing cartridges 56 a to 56 d. The roller 555 is brought into contact with the developing roller 556. As a result, the developing roller 556 is thinly and evenly coated with the liquid developer 508 containing any of yellow, magenta, cyan, and black toner. 5 6 The liquid developer layer formed on the surface of the photoconductor 10 is brought close to the electrostatic latent image formed on the surface of the photoconductor 10, and the charged toner is moved onto the photoconductor 10 by the electrostatic force. A toner image is formed.

Next, the toner image formed on the photoreceptor 10 is primarily transferred onto an intermediate transfer belt 652 as an intermediate transfer member by the transfer device 65. The toner image formed on the photoreceptor 10 is charged by the toner image formed on the photoreceptor 10 with a charge having a polarity opposite to that of the toner by the corona discharger 6556. Due to the electrostatic force generated between the belt and the intermediate transfer belt 652, the toner is moved onto the intermediate transfer belt 652 and primary-transferred. On the other hand, the photoreceptor 10 is cleaned by the cleaning device 70 to remove the liquid developer 508 remaining on the photoreceptor 10, and thereafter, is discharged by the discharging device 80. . Then, after the developing cartridge is rotated and moved to switch the developing cartridge in contact with the developing roller 556, the above-described cycle from charging to neutralization is repeated again. Thus, the yellow, magenta, cyan and black toner images are successively superimposed and transferred onto the intermediate transfer belt 652. As a result, a toner image corresponding to colorization is formed on the intermediate transfer belt 652. Next, the toner image formed on the intermediate transfer belt 652 by the transfer device 65 is formed. The toner image corresponding to the coloration is secondarily transferred to the recording medium paper. The toner image corresponding to the color formed on the intermediate transfer belt 652 corresponds to the pressing force of the secondary transfer roller 653 on the intermediate transfer belt 652 and the secondary transfer port. The bias voltage applied to the roller 6553 causes the intermediate transfer belt 652 and the secondary transfer roller 653 to move away from the intermediate transfer belt 652 having a surface layer with good releasability. Moves onto the paper conveyed by the paper feeder 610 during the second transfer and is secondary-transferred. Thereafter, the toner image corresponding to the color transferred secondarily onto the paper is thermally fused and fixed by a fixing device (not shown). Thus, a color image can be formed on paper. A fixing heater is provided inside the drive rollers 654a and Z or the secondary transfer roller 653. When the toner on the intermediate transfer belt 652 is heated, the toner image formed on the intermediate transfer belt 652 can be transferred to paper and fixed at the same time.

According to the second embodiment of the present invention, a plurality of developing cartridges 56a to '5 supplying the liquid developer for color 508a to 508d to the developing roller 556 are provided. By rotating and switching 6d, and successively contacting one developing force and one developing cartridge with the developing roller 556 to develop, only one developer support is required. It is possible to reduce the size of the liquid developing device for electrostatic latent images corresponding to the color.

In the above-described second embodiment, a rotary shaft is used as the developing device.

Rotate and switch the developing cartridges 56 a to 56 d fixed to 55 9 to sequentially apply the coating roller 55 5 of one developing cartridge to the developing roller. Although a description has been given of the one that comes into contact with the item 556, the present invention is not limited to this. The developing device may be any device that can selectively contact the developing cartridges 56a to 56d with the developing roller 55. For example, developing cartridges 56 a to 5

6 d may be switched by moving in parallel, and the developing roller 55 6 of one developing force may be brought into contact with the developing roller 55 6 in sequence.

In the above-described second embodiment, as a developing device, a developing cartridge that supplies a liquid developer 508a including toner in the mouth to a developing roller 556 is used. 5 6 a and liquid developer 5 08 b containing magenta toner to developing roller 5 5 6 The developing cartridge 56 to be supplied and the developing cartridge 56 to supply the liquid developer 508c containing cyan toner to the developing roller 556 A description has been given of an apparatus having a developing force—trigger 56 d for supplying a liquid developer 508 d containing toner to the developing roller 556, but the present invention is not limited to this. Not something. 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 roller as needed.

Further, in the above-described second embodiment, as the developing cartridge of the developing device, the liquid developer supplied to the transport roller 5554 by the supply roller 552-2a is used. A description has been given of a case in which 508 is conveyed to application roller 555 and then applied to developing roller 556, but the present invention is not limited to this. The developing force-trigger may be any as long as it supplies the liquid developer 508 to the developing roller using a roller. Also, the means for supplying the liquid developer 508 to the transport roller 554 is not limited to the supply roller 552a, but is supplied to the transport roller 554 by, for example, a bellows pump. It may be something.

Further, in the second embodiment described above, a developing device in which the liquid developer 508 adhered to the developing roller 556 is removed by a blade 557 is described. However, the present invention is not limited to this, and the developing device applies the liquid developer 508 adhered to the developing roller to the developing roller. It may be removed by a scraping roller arranged in contact with the sheet.

In the second embodiment, after the image is exposed by the exposure device 40, the preset solution 2 is placed on the photoreceptor 10 by the preset device 20. A description was given of the case where 20 was applied, but the present invention is not limited to this. The application of the splitting liquid 222 may be performed as long as it is performed prior to the developing step.

In the second embodiment, as a transfer device, the toner image formed on the photoreceptor 10 is primarily transferred to the intermediate transfer member, and then the toner image primarily transferred to the intermediate transfer member is transferred to the transfer device. Although the transfer to the recording medium is described above, the present invention is not limited to this, and the toner image formed on the photoreceptor 10 can be transferred to the recording medium. It just needs to be something that does. Although the primary transfer on the intermediate transfer member has been described as the electrostatic transfer, it may be an adhesive transfer using an adhesive.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention. For example, in each of the embodiments described above, the split device in which the split solution 220 constantly circulates inside the split solution supply body 202 is used as the split device. However, the present invention is not limited to this, and the preset device is configured to supply the preset solution only when the preset solution is used. It may supply to the supply body.

FIG. 14 shows the liquid representation of the electrostatic latent image in each of the above embodiments. FIG. 9 is a view showing a modification of the preset device used in the imaging device. The plumbing device 20 a shown in FIG. 14 is a plate-like plunger liquid supply device 800 having a length substantially equal to the image width drawn on the photoreceptor 10. And a case 804 for storing the supply side 802 a of the liquid supply unit 802, and a tank 806 for storing the liquid supply 220. A pump 808 for pumping the pre-wet solution 220 stored in the tank 806 based on a signal from the outside, a tube 810, and a displacement device (not shown). It has. The tube 810 conveys the pre-wet liquid 220 pumped by the pump 808 to the supply side 802 a of the pre-pull liquid supply body 802 . Note that a space is formed between the supply side 802 a of the split liquid supply body 802 and the case 804, and the split liquid 220 is After being stored in this space, it is supplied from the supply side 802a. When no signal is input from the outside, the displacement device holds the pre-jet liquid supply unit 102 at a position away from the photoconductor 10 as shown in Fig. 14 (A). When a signal is input from the outside, the preset liquid supply body 102 is brought into contact with the photoreceptor 10 as shown in FIG. When a signal is input from the outside, the preset device 20a supplies the preset solution 220 by the pump 208 to the preset solution supply device 8a. 0 2, and the displacing device causes the discharge side 8 0 2 b of the split liquid supply unit 8 0 2 to contact the photosensitive member 10. Veritas 2 Marker: The amount of the plumbing liquid 220 exceeding the pore volume of Kanebo Co., Ltd.) is discharged from the discharging side of the plunging liquid supply body 202 to the photoreceptor 10. Applied to As a result, it is possible to apply the pret liquid with a uniform thickness without damaging the surface of the photoreceptor.

In addition, if the pore volume of the velvet used in the plunger liquid supply is large, the amount of the plunger liquid held by the plurijet liquid supply increases, and Therefore, after the supply of the preset solution to the preset solution supply unit is started and before the application of the preset solution to the photoreceptor surface starts, the timing Occurs. Accordingly, it is desirable that the length of the pre-liquid supply body 202 be as short as possible in the flow direction of the pre-liquid 220.

Further, in each of the above embodiments, the pre-wetting device uses a pre-wetting liquid supply body formed of a continuous porous body to apply a pre-wetting to the surface of the photoreceptor. Although the application of the liquid has been described, the present invention is not limited to this. The pre-put device only needs to be capable of uniformly applying a predetermined amount of the pre-jet solution to the surface of the photoreceptor. For example, a method in which a plunger is applied by discharging a plurality of nozzles arranged in an axial direction, or a method in which a plunger is applied by a sponge roller Alternatively, a pre-wet solution may be applied using a rubber roller.

Further, in each of the above-described embodiments, the splitting solution was Although the description has been given of the one containing silicon as a main component, the present invention is not limited to this, and the viscosity of the pre-wet liquid is generally 0.5 to 5 mPa · s. If the electrical resistance value is at least ^{10 12} Ωη, the boiling point is 100 to 250 ° C, and the surface tension is 21 dyn / cm or less, silicon is not the main component. It may be. Further, when a material having releasability is coated on the surface of the image support, no special press device is required.

Further, in each of the above embodiments, the case where the organic photoreceptor is used as the image support has been described. However, the present invention is not limited to this. It is also possible to use an electrostatic recording paper such as an electrostatic probe, in which an insulator layer is formed on a conductor that directly forms an electrostatic latent image such as various photoconductors or ionography used in the above.

The present invention is not limited to the above embodiments. If the layer thickness of the developer is 5 to 4, the viscosity of the high-viscosity developer is 100 OmPas It may be. At present, high-viscosity developers with a viscosity of 600 mPas or more will be difficult to agitate the carrier liquid and toner, and will not be cost-effective. However, if it becomes available at a low price, it may be 600 mPas or more. If the viscosity exceeds 1000 mPa · s, it becomes impractical. Further, the carrier liquid of the liquid developer is not limited to silicone oil. Industrial applicability

According to the liquid developing method for an electrostatic latent image of the present invention, the liquid developer layer on the developer support and the image are rotated while rotating the elastic cylindrical developer support in a direction following the image support. By contacting the support, the contact pressure when the liquid developer layer on the developer support comes into contact with the image support can be dispersed. This prevents the liquid developer layer on the agent support from being excessively crushed, causing toner to adhere to non-image areas on the image support and disturbing the image. Is developed by forming a thin layer of liquid developer in which high density is dispersed, which facilitates miniaturization with high resolution and eliminates the emission of pollutant gas. A liquid developing method can be provided.

In addition, an outer diameter slightly smaller than the outer diameter of the developer support is provided on both sides of the developer support, and the roller is brought into contact with the image support, whereby the developer support is provided. When adjusting the pressure contact force of the liquid developer on the image support, the electrostatic pressure that can easily adjust the contact pressure when the liquid developer layer on the developer support comes into contact with the image support is adjusted. A liquid developing method for a latent image can be provided.

Also, when at least the surface of the developer support is formed of a conductive member that does not absorb the liquid developer, the liquid developer layer on the developer support comes into contact with the image support and the developer is contacted. When the support undergoes elastic deformation, the developer support absorbs and releases the liquid developer and disturbs the liquid developer layer. Thus, it is possible to provide a liquid developing method of an electrostatic latent image, which can more effectively prevent the image from being disturbed.

Further, when a developer having a foam inside is used as the developer support, a developer support having a desired value of hardness can be relatively easily obtained. It is possible to provide a liquid imaging method of an electrostatic latent image.

In addition, in the case where a pre-jet step of applying a pre-release liquid, which is a chemically inert dielectric liquid, prior to the development step is provided, the present invention In this case, since a developer support having elasticity is used, a liquid developer layer on the developer support and a pre-jet liquid layer on the image support are formed in a two-layer state in the development area. The liquid developer layer contacts the surface of the image support via the pre-pitted liquid layer, so that the non-image portion on the image support can be contacted. Thus, it is possible to provide a liquid developing method for an electrostatic latent image, which can more effectively prevent the image from being disturbed due to adhesion of a toner.

Claims

The scope of the claims

1. A liquid developing method of an electrostatic latent image formed by developing an electrostatic latent image formed on an image support with a toner, which is a charged developing particle,

Forming a thin layer of a high-viscosity liquid developer in which toner is dispersed at a high concentration in an insulating liquid on a cylindrical developer support having elasticity; Contacting the liquid developer layer on the developer support with the image support while rotating the support in a direction following the support, whereby the latent image surface of the image support is A liquid developing method for an electrostatic latent image, comprising supplying a developer.

2. On the both sides of the developer support, a roller having an outer diameter slightly smaller than the outer diameter of the developer support is provided, and the roller is brought into contact with the image support, thereby developing the image. The method according to claim 1, wherein a pressure of a developer support against the image support is adjusted.

3. The method according to claim 1, wherein the developer support has a hardness of 5 to 60 degrees JIS-A.

4. The electrostatic latent image according to claim 1, wherein the developer support has at least a surface formed of a conductive member that does not absorb the liquid developer. Liquid imaging method.

5. The liquid developing method for an electrostatic latent image according to claim 1, wherein the developer support has a foam inside.

6. Prior to the contacting step, a pre-setting step of applying a pre-setting liquid, which is a releasable and chemically inert dielectric liquid, onto the image support is performed. The liquid developing method for an electrostatic latent image according to any one of claims 1, 2, 3, 4, and 5, wherein the method is provided.

7. The pli © We Tsu DOO solution viscosity 0. 5 ~ 5 m P a · s, electric resistance 1 0 ^{1 2} Omega cm or more, a boiling point of 1 0 0-2 5

The liquid developing method for an electrostatic latent image according to claim 6, wherein the surface tension is 0 dC and the surface tension is 21 dyn cm or less.

8. The liquid developing method for an electrostatic latent image according to claim 7, wherein the pledget liquid is mainly composed of silicone oil.

9. As the high-viscosity liquid developer, one having a viscosity of 100 to 1000 mPa · s is used, and the high-viscosity liquid developer on the developer support has a thickness. The liquid developing method for an electrostatic latent image according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein is regulated to 5 to 40 t / m.

10. The liquid developer, the viscosity of the insulating liquid 0. 5 ~ 1 0 0 0 m P a · s, electric resistance 1 0 ^'2 Ω αη above, the surface tension is 2 1 dyn / cm or less, the boiling point 10. The liquid developing method for an electrostatic latent image according to claim 9, wherein the temperature is 100 ° C. or more.

11. The liquid developer uses silicone oil as an insulating liquid The liquid developing method for an electrostatic latent image according to claim 10, wherein the method is used for:

12. The liquid developer according to claim 9, 10 or 11, wherein the liquid developer contains toner having an average particle diameter of 0.1 to 5 / Zm at a concentration of 5 to 40%. Liquid development method for electrostatic latent images.

13. An electrostatic latent image liquid developing device for developing an electrostatic latent image formed on an image support by toner, which is a charged visualized particle,

Means for forming a thin layer of a high-viscosity liquid developer in which toner is dispersed at a high concentration in an insulating liquid, on a cylindrical developer support having elasticity; and Means for bringing the liquid developer layer on the developer support into contact with the image support while rotating in a direction following the support, whereby the latent image surface of the image support is provided with the liquid. A liquid developing device for an electrostatic latent image, which supplies a body developer.

14. On each side of the developer support, a roller having an outer diameter slightly smaller than the outer diameter of the developer support is provided, and the roller is brought into contact with the image support, thereby developing the image. 14. The electrostatic latent image liquid developing device according to claim 13, further comprising an adjustment mechanism for adjusting a pressing force of a developer support to the image support.

15. The electrostatic latent image liquid developing device according to claim 13, wherein the developer support has a hardness of 5 to 60 degrees JIS-A.

16. The electrostatic capacitor according to claim 13, wherein at least the surface of the developer support is formed of a conductive member that does not absorb the liquid developer. Liquid developing device for latent images.

17. The electrostatic latent image liquid developing device according to claim 13, wherein the developer support has a foam inside.

18. The image forming apparatus further comprises a presetting means for applying a splitting liquid, which is a releasable and chemically inert dielectric liquid, on the image support. Item 13. A liquid developing device for an electrostatic latent image according to Item 13, 14, 15, 15 or 16 or 17.