JPH07209998A - Liquid development method and device for electrostatic latent image - Google Patents

Abstract

PURPOSE:To provide electrostatic latent image liquid developing to method and device capable of applying a prewet solution a uniform thickness. CONSTITUTION:The electrostatic latent image liquid developing method for developing an electrostatic latent image formed on a photosensitive body 10 by toner is provided with a prewet process for coating the body 10 with the prewet solution to be dielectric solution having releasing property and a chemically inactive characteristic by abutting a prewet solution feeder formed by a member impregnate with the prewet solution and having solution permeability and a solution holding property upon the body 10 and a developing process for supplying a liquid developer to the surface of the latent image formed on the body 10 by allowing the liquid developer with high density and high viscosity applied to the surface of a developing roller 506 to contact with the body 10.

Description

Detailed Description of the Invention

[0001]

The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a liquid developing method and a liquid developing apparatus for an electrostatic latent image, which 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 a liquid developing method of an electrostatic latent image formed on a image support by a toner which is a developing particle, an electrostatic latent image is developed on a non-image portion on the image support. In order to prevent the toner from adhering, a method is known in which a pre-wet liquid using the same medium as the dispersion medium of the liquid developer is applied onto the image support prior to the developing step. As a method of applying the pre-wet liquid, by installing a blade provided with a slit for flowing out the pre-wet liquid in the vicinity of the image support without contacting the pre-wet liquid, the pre-wet liquid is provided between the image support and the blade. There is a method (Japanese Patent Laid-Open No. 4-1687) of forming a liquid pool and applying the pre-wet liquid by this.

[0003]

However, in the method disclosed in Japanese Patent Laid-Open No. 4-1687, it is difficult to maintain a certain distance between the blade and the image support,
For this reason, there is a problem that the pre-wetting liquid cannot be applied to the image support with a uniform thickness, and therefore the toner cannot be sufficiently prevented from adhering to the non-image portion on the image support. In addition, there is a problem that it is difficult to manufacture the blade.

Further, the conventional pre-wet liquid coating method is
It is generally used for a low-viscosity liquid developer obtained by mixing toner in an organic solvent Isopar (registered trademark: Exxon) at a ratio of about 1 to 2%. In the case of using a highly viscous liquid developer of 100 to 10,000 mPa · s in which the toner is dispersed in the insulating liquid at a higher concentration, any method can be used as a method for preventing toner adhesion to the non-image portion on the image support. It was not clear if was suitable. Since such a high-viscosity liquid developer increases the adhesion to the surface of the image support, it is necessary to develop an appropriate toner adhesion prevention method.

[0005]

[Purpose] The present invention has been made based on the above circumstances, and it is possible to apply a pre-wetting liquid with a uniform thickness, and therefore to prevent toner from adhering to a non-image portion on an image support. It is an object of the present invention to provide a liquid developing method and a liquid developing apparatus for an electrostatic latent image capable of performing the above.

[0006]

In order to achieve the above object, a liquid developing method for an electrostatic latent image according to claim 1, wherein the electrostatic latent image formed on the image support is charged with a visible image. A liquid developing method for an electrostatic latent image, which is developed with a toner that is a derivatized particle, wherein a pre-wetting liquid, which is a dielectric liquid that is releasable and chemically inert, has liquid permeability prior to the developing process. And impregnating a pre-wet liquid supply body formed of a liquid-retaining member, and applying the pre-wet liquid onto the image support by bringing the pre-wet liquid supply body into contact with the image support. By a pre-wetting step and a high-viscosity liquid developer of 100 to 10000 mPa · s in which the toner is dispersed in a high concentration in the insulating liquid applied on the developer support, is brought into contact with the image support. , In front of the latent image surface of the image support A developing step of supplying the liquid developer and is characterized in that it comprises.

According to a second aspect of the present invention, there is provided the liquid latent image developing method according to the first aspect, wherein the pre-wet liquid supply body is formed in a plate shape. .

According to a third aspect of the present invention, in the liquid latent image developing method according to the first aspect, the pre-wetting step causes the pre-wet liquid supply member to move in a direction opposite to the rotation direction of the image support. The pre-wetting liquid is applied onto the image support by contacting the image support while rotating.

According to a fourth aspect of the present invention, in the liquid latent image developing method according to the first, second or third aspect, the member is a continuous porous body having a three-dimensional network structure having continuous pores. It is a feature.

According to a fifth aspect of the present invention, in the liquid developing method for an electrostatic latent image according to the first, second, third or fourth aspect, the pre-wet liquid supply member is partially immersed in the pre-wet liquid. It is characterized by that.

According to a sixth aspect of the present invention, there is provided a liquid developing method for an electrostatic latent image according to the first, second, third, fourth or fifth aspect of the invention.
The viscosity of the insulating liquid of the liquid developer is 0.5 to 1000.
It is characterized by having mPa · s, electric resistance of 10 ¹² Ωcm or more, surface tension of 21 dyn / cm or less, and boiling point of 100 ° C. or more.

According to a seventh aspect of the present invention, there is provided a liquid developing method for an electrostatic latent image according to the sixth aspect, wherein the liquid developer is
It is characterized in that silicon oil is used as an insulating liquid.

According to an eighth aspect of the invention, in the liquid developing method for an electrostatic latent image according to the first, second, third, fourth, fifth, sixth or seventh aspect, the liquid developer has an average particle size of 0.1 to 0.1. It is characterized by containing a toner of 5 μm at a concentration of 5 to 40%.

According to a ninth aspect of the invention, in the liquid developing method for an electrostatic latent image according to the first, second, third, fourth, fifth, sixth, seventh or eighth aspect, the viscosity of the pre-wet liquid is 0.5. ~ 5m
Pa · s, electric resistance of 10 ¹² Ωcm or more, boiling point of 100
It is characterized in that the surface tension is up to 250 ° C and the surface tension is 21 dyn / cm or less.

A liquid developing method for an electrostatic latent image according to a tenth aspect is characterized in that, in the invention according to the ninth aspect, the pre-wetting liquid contains silicon oil as a main component. .

A liquid developing device for an electrostatic latent image according to claim 11, wherein the electrostatic latent image formed on the image support is developed by a toner which is a charged image-forming particle. In the developing device, a pre-wet liquid supply member formed of a member having liquid permeability and liquid retention impregnated with a pre-wet liquid that is a dielectric liquid having releasability and chemically inert, A pre-wetting means for applying the pre-wetting liquid onto the image support by bringing the pre-wet liquid into contact with the image support,
The image support is brought into contact with a high-viscosity liquid developer of 100 to 10,000 mPa · s in which a toner is dispersed in high concentration in an insulating liquid applied on the developer support. And a developing unit that supplies the liquid developer to the latent image surface.

According to a twelfth aspect of the present invention, there is provided the electrostatic latent image liquid developing device according to the eleventh aspect of the present invention, wherein the pre-wet liquid supply body is formed in a plate shape. .

According to a thirteenth aspect of the present invention, there is provided the electrostatic latent image liquid developing device according to the eleventh aspect of the present invention, wherein the pre-wet means moves the pre-wet liquid supply member in a direction opposite to the rotation direction of the image support. It is characterized in that the pre-wetting liquid is applied onto the image support by bringing it into contact with the image support while rotating.

According to a fourteenth aspect of the invention, in the liquid latent image developing device of the eleventh aspect, the member is a continuous porous body having a three-dimensional network structure with continuous pores. It is characterized by.

A liquid developing apparatus for an electrostatic latent image according to a fifteenth aspect is the invention according to the eleventh, twelve, thirteenth or fourteenth aspect, wherein a part of the prewetting liquid supply body is immersed in the prewetting liquid. It is characterized by that.

[0021]

A liquid developing method for an electrostatic latent image according to claim 1, wherein a member which has a releasability and a chemically inert inert liquid, a prewetting liquid, is liquid-permeable and liquid-retaining. The pre-wet liquid supply body formed by the above is impregnated, and the pre-wet liquid is applied onto the image support by bringing the pre-wet liquid supply body into contact with the image support. It can be applied with a uniform thickness, and thus toner can be prevented from adhering to the non-image portion on the image support. Further, by using the liquid developer in which the toner is dispersed at a high concentration, the liquid amount can be made much smaller than that of the conventional low concentration liquid developer. When the viscosity of the 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 developer. Therefore, 1000
A liquid developer of 0 mPa · s or more becomes unrealistic in terms of cost and becomes unrealistic. On the other hand, when it is 100 mPa · s or less, the toner concentration becomes low and the dispersibility of the toner becomes poor, so that it becomes impossible to develop the developer in a thin layer. 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. Also,
The higher the viscosity, the thinner it needs to be.

In the liquid developing method for an electrostatic latent image according to a second aspect of the present invention, the plate-shaped pre-wet liquid supply member is used, so that the pre-wet liquid is formed on the image support as needed. It is easy to apply.

According to a third aspect of the present invention, there is provided a liquid developing method for an electrostatic latent image, wherein the pre-wet liquid supply member is brought into contact with the image support while rotating the pre-wet liquid supply member in a direction opposite to the rotation direction of the image support. The pre-wet liquid held by the supply member is discharged at the contact start side between the image support member and the pre-wet liquid supply member, and the image supporting member has a uniform thickness at the contact portion between the image support member and the pre-wet liquid supply member. Applied on the body. Therefore, as the pre-wetting liquid is consumed, a fresh pre-wetting liquid can always be applied on the image support with a uniform thickness.

According to a fourth aspect of the present invention, there is provided a liquid developing method for an electrostatic latent image, wherein a pre-wetting liquid is held in the pores to support an image by using a continuous porous body having a three-dimensional network structure having continuous pores as a member. Can be fed on the body. Further, the supply amount of the pre-wet liquid to the image support can be controlled by the pore diameter and the porosity of the pre-wet supply body.

According to a fifth aspect of the present invention, there is provided a liquid developing method for an electrostatic latent image, wherein a part of the pre-wet liquid supply member is immersed in the pre-wet liquid to continuously supply the pre-wet liquid onto the image support. be able to.

According to a sixth aspect of the present invention, there is provided an electrostatic latent image liquid developing method, wherein an insulating liquid having the above characteristics 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 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 extremely small. Therefore, the insulating liquid absorbed by the paper or the like at the time of transfer becomes extremely small, so that the problem of the insulating liquid adhering to the paper or the like does not occur if the viscosity is 1000 mPa · s or less. 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 there is a problem in the method of storing the developer, the entire device must be of a closed structure, and it is difficult to improve the working environment. Become. Electric resistance is 10 ¹² Ω
When it is less than 10 cm, the insulating property is deteriorated and it 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.

According to a seventh aspect of the present invention, there is provided a liquid developing method for an electrostatic latent image, wherein the insulating liquid is mainly composed of silicone oil. Can be obtained.

In the liquid developing method for an electrostatic latent image according to claim 8, the liquid developer comprises 5 toner particles having an average particle diameter of 0.1 to 5 μm.
By containing it at a concentration of -40%, it is possible to obtain a liquid developer in which the toner is dispersed in the insulating liquid at a high concentration. Also, in proportion to the particle size of the toner,
The resolution is improved. Usually, the toner is present in the form of lumps of about 5 to 10 particles. Therefore, if the average particle diameter of the toner is 5 μm or more, the resolution becomes poor. On the other hand, when the average particle diameter of the toner is 0.1 μm or less, the physical adhesive strength increases, and it becomes difficult to remove the toner during transfer.

In the liquid developing method for an electrostatic latent image according to a ninth aspect, since the pre-wetting liquid has the above-mentioned characteristics, a more preferable pre-wetting liquid having releasability and good insulation is obtained. be able to. 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. When the viscosity is 0.5 to 5 mPa · s, it easily evaporates and is desirable. When the viscosity is 5 mPa · s or more, it becomes difficult to evaporate, and when 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 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 be hermetically sealed, 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 liquid developing method for an electrostatic latent image according to a tenth aspect, the prewetting liquid contains silicone oil as a main component, so that a prewetting liquid satisfying the characteristics according to the ninth aspect and safe can be obtained. Obtainable.

The operation of the liquid developing device for an electrostatic latent image according to claim 11 is the same as that of the invention according to claim 1.

The operation of the electrostatic latent image liquid developing device according to the twelfth aspect is the same as that of the invention according to the second aspect.

The operation of the liquid developing device for an electrostatic latent image described in claim 13 is the same as the operation of the invention described in claim 3.

The operation of the liquid developing device for an electrostatic latent image described in claim 14 is the same as the operation of the invention described in claim 4.

The operation of the electrostatic latent image liquid developing device according to the fifteenth aspect is similar to that of the invention according to the fifth aspect.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 is a schematic configuration diagram of an electrostatic recording apparatus which is an embodiment of the present invention, FIG. 2 is a schematic perspective view of a pre-wetting apparatus used in the electrostatic recording apparatus shown in FIG. 1, and FIG. FIG. 4 is a diagram for explaining the operation of the electrographic recording device.
2 is a diagram for explaining the operation of the pre-wet device shown in FIG. 2, and 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.

As shown in FIG. 1, the electrostatic recording apparatus of this embodiment comprises a photoconductor 10 which is an image support, a prewetting device 20 for applying a prewetting liquid on the photoconductor 10, and a photoconductor 10. The electrostatic latent image is visualized by charging the charging device 30, the exposure device 40 that exposes the image on the photoconductor 10, and the toner to the portion of the photoconductor 10 where the electrostatic latent image is formed. The developing device 50 includes a developing device 50, a transfer device 60 that transfers the toner on the photoconductor 10 to a predetermined paper P, a cleaning device 70 that removes the toner adhering to the photoconductor 10, and a charge eliminating device 90. .

Charging device 30, exposure device 40, transfer device 6
For 0, the cleaning device 70, and the static eliminator 90, 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-mentioned devices is omitted, and the pre-wetting device 20 and the developing device 5 which are the main parts of the present invention are omitted.
0 will be described.

The pre-wetting device 20 of this embodiment is shown in FIG.
As shown in, a plate-shaped pre-wet liquid supply body 202 having a length substantially the same as the image width drawn on the photoconductor 10, a case 204 for housing the pre-wet liquid supply body 202,
Tank 206 for storing the pre-wet liquid, and tank 20
Pump 20 for pumping the pre-wet liquid stored in 6
8, conduits 210a and 210b, and a contact / separation device 212 that separates and contacts the pre-wet liquid supply body 202 from the photoconductor 10.

The pre-wet liquid supply body 202 is made of BELEATER (registered trademark: Kanebo Co., Ltd.). The bell eater is a continuous porous body having a three-dimensional network structure in which pores are continuous, and can hold the pre-wet liquid for the volume of the pores. Further, when the pre-wet liquid exceeding the volume of the pores is supplied, as shown in FIG. 5, the pre-wet liquid in an amount exceeding the volume of the pores is discharged from the discharge side 202b of the pre-wet liquid supply body 202 and the pre-wet liquid is also supplied. It is discharged from the bottom surface of the liquid supply body 202. Case 2
As shown in FIG. 4, an opening 204a is provided on the surface of No. 04 facing the photoconductor 10 so that the bottom surface of the pre-wet liquid supply body 202 can be brought into contact with the photoconductor 10. The pipeline 210a conveys the pre-wet liquid pumped up by the pump 208 to the supply side 202a of the pre-wet liquid supply body 202. Pre-wet liquid supply body 20
The space portion 2 is provided between the supply side 202a of the two and the case 204.
04b is formed, and the pre-wet liquid is stored in the space 204b, and then supplied from the supply side 202a to the pre-wet liquid supply body 202. The pipeline 210 b conveys the pre-wet liquid discharged from the discharge side 202 b of the pre-wet liquid supply body 202 to the tank 206.

The connecting / disconnecting device 212 is fixed to the main body of the apparatus and has a shaft 213a rotatably attached to the lower end of the case 204, and cams 214a provided at both ends of a shaft 213b fixed to the main body of the apparatus. 214b and the cam 21
A spring 215 for abutting the cases 4a and 214b on the case 204
a, 215b, and a drive device (not shown) that rotationally drives the shaft 213b. A drive device (not shown) uses the cams 214a, 2a based on a signal from the outside.
By rotating 14b to rotate the case 204 into the shaft 2
It rotates around 13a. As a result, when the pre-wet liquid is not applied on the photoconductor 10, the pre-wet liquid supply body 202 is held at a position away from the photoconductor 10 as shown in FIG. When applying the pre-wetting liquid, as shown in FIG. 4B, the pre-wetting liquid supply body 202 is brought into contact with the photoconductor 10.

In the developing device 50 of this embodiment, a metal developing roller 506 is used as a developer supporting member that conveys the liquid developer to the surface of the photoconductor 10, and the liquid developing agent is applied to the developing roller 506 by a pump 504. Supplied. Developing roller 5
The formation of the toner layer on 06 was performed using the layer forming roller 510. Regarding the layer forming method, in addition to the method of using a roller as in this embodiment, there is a method of using a rubber or rigid blade, but any method can be used as long as it can uniformly apply a thin toner layer on a developing roller. Any method may be used. Further, the developer support is not limited to the rigid developing roller. For example, a developing belt formed of a flexible belt member such as a seamless metal belt such as a nickel belt or a resin belt such as a polyimide film may be used. The surface of the resin belt is made conductive so that a developing bias can be applied, or conductive fine particles are added to the material of the belt to lower the electric resistance value so that the belt has conductivity or semiconductivity. There is a need.

Next, the image forming material used in this embodiment will be described. The liquid developer used in this embodiment is a toner which is a resin which is an adhesive such as epoxy, a charge control agent which gives a predetermined charge to the toner, a color pigment, a dispersant which uniformly disperses the color pigment, and a carrier. It consists of liquid.
The constitution of the toner is basically the same as that used in the conventional liquid developer, but the amount thereof is changed so as to be compatible with the silicone oil in order to adjust the charging characteristics. 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. Since the liquid developer layer formed on the developer support is formed in a thin layer, the carrier liquid contained in the liquid developer layer is extremely small, so that it is supplied to the latent image surface of the photoconductor 10. The amount of carrier liquid contained in the liquid developer is extremely small. Therefore, the carrier liquid absorbed by 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 on the paper or the like 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. In addition, the carrier liquid has a viscosity of 20.
When the image output experiment was conducted using KF-96-20 manufactured by Shin-Etsu Silicon Co., Ltd., which has mPa · s, no carrier liquid remained on the paper after fixing. 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-96-2
0 is generally used for cosmetics and has high safety such as toxicity. There are many types of carrier liquids such as KF9937 manufactured by Shin-Etsu Silicon Co., Ltd. as carrier liquids containing silicon oil and the like, and any one may be selected as long as electrical resistance, evaporation characteristics, surface tension, safety and the like are satisfied. Good.

Further, according to experiments by the inventors, when the surface tension is large, fog or toner lumps may adhere, and experimentally, when the surface tension is 21 dyn / cm or more, a problem occurs in image quality. I found it easy.

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. For example, DC344, Dow Corning Corp.
DC200-0.65, -1.0, -2.0, KF96L-1, KF9937 manufactured by Shin-Etsu Silicon Co., and the like. Generally, it is necessary 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 laws and regulations as a dangerous material. In addition, the boiling point must be 250 ° C. or lower because of the effect 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 fog, and improve the resolution of the image quality. According to experiments conducted by the present inventors, 20 to 21
The limit is about dyn / cm, and it is necessary to select one lower than this.

When the electric resistance is low, the latent image charge leaks to blur the image. 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 apparatus of this embodiment will be described. First, as shown in FIG. 3A, the above-described pre-wetting liquid is applied onto the photoconductor 10 by the pre-wetting device 20. The pre-wetting device 20 brings the pre-wetting liquid supply body 202 into contact with the photoconductor 10 based on a signal from the outside. The pre-wet liquid 220 is constantly circulated inside the pre-wet liquid supply body 202 by the pump 208, and the pre-wet liquid exceeding the volume of the pores of the bell eater which is the pre-wet liquid supply body 202 is as shown in FIG. Then, it is discharged from the discharge side 202 b of the pre-wet liquid supply body 202, is discharged from the bottom surface of the pre-wet liquid supply body 202, and is applied onto the photoconductor 10.

Next, as shown in FIG. 3B, the photoreceptor 10 coated with the pre-wetting liquid is charged by the charging device.
The charges carried by the ions pass through the pre-wet liquid layer and reach the surface of the photoconductor surface 10. A corona discharger is generally used as the charging device. 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. As shown in FIG. 3C, the portion of the laser scanner exposed to the light becomes conductive, and the charge disappears, and the portion not exposed to the light remains as an electrostatic latent image which is an image of the charge.

Next, the electrostatic latent image is visualized by the developing device 50. A liquid developer is supplied to the developing roller 506 by the pump 504 provided in the developing tank 502, and a thin layer is formed on the developing roller 506 by the layer forming roller 510.
The liquid developer layer thus formed on the developing roller 506 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 toner is moved onto the photoconductor 10. Next, FIG.
As shown in (E), the electrostatic force generated by the voltage applied to the transfer roller 602 of the transfer device 60 causes the photoconductor 10 to move.
The upper toner image is transferred to the paper P. 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. Fix it on the paper. On the other hand, the liquid developer remaining on the photoconductor 10 is removed by the cleaning device 70. In addition,
After the photoconductor 10 is neutralized by a static eliminator (not shown),
It is repeatedly used again in the cycle from pre-wet to static elimination.

6 to 10 are diagrams for explaining the developing process of this embodiment in detail, FIG. 6 is a diagram for explaining the entire developing process, and FIG. 7 is a diagram for showing an approaching process. FIG. 8 is a diagram showing a state of a toner moving process, FIG. 9 is a diagram showing a separation process of a non-image part, and FIG. 10 is a diagram showing a separation process of an image part. In the developing process of this embodiment, as shown in FIG. 6, the developing roller approaches the photoconductor and the liquid developer approaches the photoconductor surface, and the liquid developer layer and the pre-wet liquid layer are soft. It is composed of three processes: a toner moving process in which the toner moves in contact with the toner, and a separation process in which the developing roller is separated from the photoconductor and is separated into toner adhering to the developing roller and toner adhering to the photoconductor. it is conceivable that.

In the approaching process, as shown in FIG. 7, since the developing roller 506 and the photoconductor 10 are installed with a minute gap, that is, the space d, a high-viscosity liquid developer composed of carrier liquid and toner, Soft contact with the pre-wet liquid. Due to this contact, the pre-wetting liquid having a lower viscosity is slightly pushed out, and a liquid pool of the pre-wetting liquid is generated.

In the process of moving the toner, as shown in FIG. 8, in the image portion, the toner forms a pre-wet liquid layer mainly by the Coulomb force due to the electric field formed between the charge on the photoconductor 10 and the developing roller 506. It passes and moves 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, the 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 roller 506 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 roller 506, a part of the carrier liquid and a part of the pre-wet liquid remaining after the toner moves form a cover film 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 to the developing roller 506 is too thick, the viscosity of the liquid developer is high, so that electrostatic force can cause the developing roller 506 to move to the photosensitive member 10.
The toner group that is about to move to the surface of the toner forms a cluster by winding the toner around it and moves to the surface of the photoconductor 10, so that excessive adhesion of the toner occurs and image noise occurs. 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 how the developing roller and the photosensitive member are in hard contact with each other, 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. Therefore, in this embodiment, as shown in FIG.
When 6 and the photoconductor 10 are brought into hard contact with each other, the low-viscosity pre-wet liquid layer is removed and the two-layer state cannot be maintained. Therefore, as shown in FIG. It is necessary to install the developing roller 506 so that a minute gap, that is, a gap d is provided between the developing roller 506 and the surface of the developing roller 506. Incidentally, as shown in FIG. 13B, a developing belt 520 formed of a flexible belt member may be used for the developer support. In this case, by adjusting the tension of the developing belt 520 to disperse the contact pressure when the pre-wet liquid layer on the photoconductor 10 and the liquid developer layer on the developing belt 520 contact each other, the photoconductor 10 and the developing belt 520 can be dispersed. There is a gap with 520. Therefore, the two-layer state of the pre-wet liquid layer and the liquid developer layer can be maintained in the developing process.

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 is slightly thicker than the layer thickness capable of supplying the toner development amount (that is, the density when solid black is produced) required at the time of development. This is because a highly viscous liquid developer is used, so if the layer thickness is too thick, electrostatically selected toner will move to the photoconductor along with neighboring toner due to the viscosity of the liquid. In addition, extra toner adheres to the image, resulting in image smearing. In an experiment conducted by the inventors, a developer having a high toner concentration is 5 μm and a developer having a low toner concentration is 40 μm.
A good image was obtained with a layer thickness of the order. When a developer having a toner concentration of 20 to 30% is used, the toner layer thickness is 8 to
Good image quality was obtained at about 20 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 thick, the charge of the latent image flows, the sharpness and the resolution are lowered, and the flow of toner occurs during development, and the sticky image tends to be blurred. In the experiment using DC344,
Good results were obtained with a thickness of 30 μm or less, particularly with a thickness of 20 μm or less. For those with lower viscosity,
From this result, good results can be obtained even if the thickness is thin or thick.
However, for high viscosity ones, the optimum value tends to have a narrow range.

As in the conventional developing method, the narrower the gap between the photosensitive member and the developer support, 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 developer support 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, depending on the difference in the viscosity of the liquid developer and the toner concentration, 5 μ
It was set between m and 50 μm.

As a result of carrying out the image drawing experiment under the above-mentioned conditions, the results shown in Table 1 were obtained. From these results, the optimum range of the liquid developer and the viscosity of the pre-wet liquid for the developing method of this embodiment is 100 mP for the liquid developer.
a · s to 6000 mPa · s, pre-wet liquid is 0.
It was found to be between 5 mPa · s and 5 mPa · s. In addition, the image quality changes depending on the thickness of the liquid developer layer on the developing roller, the thickness of the pre-wet liquid layer, the minute gap that is the development gap, etc. There is a 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-wetting liquid was DC200 series manufactured by Dow Corning, and the carrier liquid of the developing liquid was DC345 manufactured by the same company.

[0065]

[Table 1]

According to the first embodiment of the present invention, the plate-shaped pre-wet liquid supply body 202 formed of bell eater is impregnated with the pre-wet liquid, and this pre-wet liquid supply body 20 is used.
Since the pre-wetting liquid is applied to the surface of the photoconductor 10 by bringing 2 into contact with the photoconductor 10 as the image support,
The pre-wetting liquid can be applied with a uniform thickness without damaging the surface of the photoconductor, and therefore toner can be prevented from adhering to the non-image area on the photoconductor. Further, by using the plate-shaped pre-wet liquid supply body, it becomes easy to apply the pre-wet liquid on the image support, if necessary.

If the volume of the pores of the bell eater is large, the amount of the pre-wet liquid held by the pre-wet liquid supply body increases, so that the pre-wet liquid is supplied to the pre-wet liquid supply body before the pre-wet liquid is supplied. There is a time lag before the application of the liquid to the surface of the photoreceptor is started. However, in the present embodiment, such a time lag does not occur because the pre-wet liquid constantly circulates inside the pre-wet liquid supply body 220.

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

A conventional liquid developer is an isoparaffin solvent such as Isopar (registered trademark: Exxon) as a carrier liquid.
Manufactured by the company) is used. Since this Isopar does not have a high resistance value, when the toner concentration is increased, the chargeability of the toner deteriorates. Therefore, in the case of Isopar, there is a limit to the toner density. On the other hand, since the silicone oil used in this embodiment has a large resistance value, the toner concentration can be increased. Further, in the case of Isopar, the toner is in a partially melted state, so that the dispersed state of the toner is improved. Therefore, even if the toner concentration is 1 to 2%, the toner particles repel each other, so that the toner particles are uniformly dispersed. On the other hand, when the toner concentration is 1 to 2%, the silicone oil has poor dispersibility and will be precipitated soon. However, when the toner concentration is set to 5 to 40%, the toner is densely packed and stably dispersed. Therefore, in this embodiment, the high-viscosity liquid developer in which the toner is dispersed at a high density can be 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, since the silicone oil used in this example is a safe liquid as is apparent from the fact that it is used for cosmetics, according to this example, the working environment should be improved. And there is no pollution problem.

In the first embodiment of the present invention, as the pre-wetting device, the one in which the pre-wetting liquid constantly circulates inside the pre-wetting liquid supply body 202 has been described.
The present invention is not limited to this, and the pre-wet device may supply the pre-wet liquid to the pre-wet liquid supply body only during pre-wetting.

FIG. 14 is a diagram showing a modification of the pre-wetting device used in the electrostatic recording apparatus according to the first embodiment of the present invention. The pre-wetting device 80 shown in FIG. 14 houses a plate-shaped pre-wet liquid supply body 802 having a length substantially the same as the image width drawn on the photoconductor 10, and a supply side 802 a of the pre-wet liquid supply body 802. A case 804, a tank 806 for storing the pre-wet liquid, a pump 808 for pumping the pre-wet liquid stored in the tank 806 based on a signal from the outside, a pipe line 810, and a connecting / disconnecting device (not shown) are provided. . The pipe line 810 conveys the pre-wet liquid pumped up by the pump 808 to the supply side 802 a of the pre-wet liquid supply body 802. A space is formed between the supply side 802a of the pre-wet liquid supply body 802 and the case 804.
0 is stored in this space and then supplied from the supply side 802a. When a signal from the outside is not input, the separation / contact device holds the pre-wet liquid supply body 802 at a position apart from the photoconductor 10, as shown in FIG.
When a signal from the outside is input, the pre-wet liquid supply body 802 is connected to the photoconductor 10 as shown in FIG.
Abut. The pre-wet device 80 supplies the pre-wet liquid to the pre-wet liquid supply body 802 by the pump 208 when a signal from the outside is input, and the discharge side 802b of the pre-wet liquid supply body 802 is made to be a photosensitive body by the separation / contact device. Abut on 10. Pre-wet liquid supply body 802
The pre-wetting liquid that exceeds the pore volume of BELITA (registered trademark: Kanebo Co., Ltd.) is discharged from the discharge side 802b of the pre-wetting liquid supply body 802 and applied onto the photoconductor 10. As a result, as in the case described above, the pre-wetting liquid can be applied with a uniform thickness without damaging the surface of the photoconductor, and therefore, the non-image area on the photoconductor where the electrostatic latent image is not formed is formed. Toner can be prevented from adhering.

If the volume of the pores of the bell eater used for the pre-wet liquid supply body is large, the amount of the pre-wet liquid held by the pre-wet liquid supply body increases, so that the pre-wet liquid supplied to the pre-wet liquid supply body is increased. There is a time lag between the start of the supply and the start of the application of the pre-wet liquid to the surface of the photoconductor. Therefore, it is desirable that the length of the pre-wet liquid supply body 802 is as short as possible in the flow direction of the pre-wet liquid.

Further, in the first embodiment of the present invention, the description has been made of the case where BELITA (trademark: Kanebo Co., Ltd.) is used as the pre-wet liquid supply body, but the present invention is not limited to this. The pre-wet liquid supply body may be a continuous porous body having a three-dimensional network structure in which pores are continuous, or a member formed of a member having liquid permeability and liquid retention, and the shape may be plate-like. The shape is not limited and may be, for example, a roll shape.

Next, the second embodiment of the present invention will be described with reference to FIG.
16 and FIG. 16. FIG. 15 is a schematic diagram of a pre-wetting device used in the electrostatic recording apparatus according to the second embodiment of the present invention, and FIG. 16 is a schematic diagram of the pre-wetting liquid supply body shown in FIG.

The electrostatic recording apparatus according to the second embodiment of the present invention differs from the electrostatic recording apparatus according to the first embodiment of the present invention shown in FIG. 1 in place of the pre-wetting apparatus 20. Was used. Other configurations are similar to those of the first embodiment. Therefore, the schematic diagram of the electrostatic recording apparatus according to the second embodiment of the present invention is omitted, and the second embodiment of the present invention has the same function as the electrostatic recording apparatus shown in FIG. A detailed description thereof will be omitted by adding a reference numeral or a corresponding reference numeral.

As shown in FIG. 15, the pre-wetting device 22 is a columnar elastic pre-wetting liquid as shown in FIG. 16 having a length substantially the same as the image width drawn on the photoconductor 10. A supply body 222, a tank 224 that stores the pre-wet liquid, a pump 226 that pumps up the pre-wet liquid stored in the tank 224, and a pipe that conveys the pre-wet liquid pumped up by the pump 226 to the pre-wet liquid supply body 222. A passage 228, a guide 230, and a liquid receiver 232 are provided.

The pre-wet liquid supply body 222 rotates in a direction opposite to the rotation direction of the photoconductor 10 by a driving device (not shown). According to the experiments conducted by the present inventors, regarding the formation of a thin layer of the pre-wet liquid on the photoconductor 10, good results are obtained when the peripheral speed of the pre-wet liquid supply body 222 is substantially the same as the peripheral speed of the photoconductor 10. Was obtained. Further, in order to prevent plastic deformation, the pre-wet liquid supply body 222 is normally held at a position away from the photoconductor 10 by a displacement device (not shown), and only during pre-wet as shown in FIG. Abut. For the pre-wet liquid supply body 222, a continuous porous body sponge having a three-dimensional network structure with continuous pores is used. The continuous porous body sponge can hold the pre-wet liquid only for the volume of the pores, and by applying pressure to change the volume of the pores,
The held pre-wetting liquid can be released. In the present example, an average pore diameter of 100 to 800 μm and a hardness of 20 to 50 degrees are used, and a pre-wet of 200 to
It was brought into contact with the photoreceptor with a pressing force of 1000 g / cm. The guide 230 includes a pre-wet liquid discharge side 228 of the pipe line 228.
The pre-wet liquid is disposed around the a so as to cover a part of the pre-wet liquid supply body 222, and the pre-wet liquid is formed in the space 2 formed between the guide 230 and the pre-wet liquid supply body 222.
After being stored in 30 a, it is absorbed by the pre-wet liquid supply body 222. The liquid receiver 232 is the pre-wet liquid supply body 2.
Excessive pre-wet liquid, which is disposed below 22 and is discharged from the pre-wet liquid supply body 222, is returned to the tank 224.

According to the second embodiment of the present invention, as shown in FIG. 15, a pre-wet supply body 22 which is a columnar elastic body formed of a continuous porous sponge for pre-wetting liquid is used.
2 is impregnated and the pre-wet supply body 222 is rotated in the direction opposite to the rotation direction of the photoconductor 10 while the photoconductor 10 is rotated.
The pre-wet liquid supply member 222 is elastically deformed. Therefore, the pre-wet liquid supply body 22
The pre-wet liquid held by 2 is discharged at the contact start side 222a between the photoconductor 10 and the pre-wet liquid supply body 222, and by the nip 222b formed between the photoconductor 10 and the pre-wet liquid supply body 222. Photoreceptor 1 with uniform thickness
The excess pre-wet liquid applied onto the photoconductor 10 and supplied onto the photoconductor 10 is again absorbed by the prewet liquid supply body 222 at the contact end side 222c between the photoconductor 10 and the prewet liquid supply body 222. To be done. As a result, the pre-wetting liquid can be applied with a uniform thickness without damaging the photoconductor, and thus it is possible to prevent the toner from adhering to the non-image portion on the photoconductor and disturbing the image. It is possible to prevent the region other than the pre-wet liquid application region on the photoconductor from getting wet with the pre-wet liquid.

In the second embodiment of the present invention, as the pre-wet device, the one in which the pre-wet liquid is pumped up by the pump 226 and supplied to the pre-wet liquid supply body 222 has been described, but the present invention is not limited to this. Not something. For example, as in the pre-wetting device 24 shown in FIG.
The pre-wet liquid is stored in the pre-wet liquid by setting it in the pre-wet liquid 222.
May be supplied to

Further, in the second embodiment, the case where the continuous porous body sponge is used as the pre-wet liquid supply body has been described, but the present invention is not limited to this.
The pre-wet supply body may be formed of an elastic member having liquid permeability and liquid retention, and the shape thereof is not limited to the columnar shape, for example, as shown in FIG.
It may be formed in an endless belt shape as shown in (A) and (B).

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 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. The image support may be various types of photoconductors used in the Carlson method, or those in which an insulating layer is formed on a conductor that directly forms an electrostatic latent image such as ionography, or electrostatic recording paper such as an electrostatic plotter.

Further, in each of the above-mentioned embodiments, the case where the pre-wetting device is used to apply the pre-wetting liquid and then the charging device is used to charge the photosensitive member has been described, but the present invention is not limited to this. However, the application of the pre-wet liquid may be performed before the developing step. The pre-wetting liquid has a viscosity of 0.5 to 5 m.
Pa · s, electric resistance of 10 ¹² Ωcm or more, boiling point of 100
If the surface tension is ~ 250 ° C and the surface tension is 21 dyn / cm,
It does not have to contain silicon as a main component.

Further, the present invention is not limited to the above-mentioned respective embodiments, and if the liquid developer layer has a layer thickness of 5 to 40 μm, the viscosity of the liquid developer may be 10,000 mPa · s. good. 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.

[0085]

As described above, according to the first aspect of the present invention, the prewetting liquid, which is a dielectric liquid having releasability and chemically inactive, has liquid permeability and liquid retention property. Since the pre-wet liquid supply body formed of a certain member is impregnated and the pre-wet liquid supply body is brought into contact with the image support to apply the pre-wet liquid on the image support, the pre-wet on the image support is performed. The liquid can be applied with a uniform thickness,
Therefore, it is possible to prevent the toner from adhering to the non-image portion on the image support, and by using the liquid developer in which the toner is dispersed at a high concentration, the liquid developer is made into a thin layer. By developing, it is possible to provide a liquid developing method for an electrostatic latent image, which has a high resolution, can be easily miniaturized, and can reduce pollution.

According to the second aspect of the present invention, by using the plate-shaped pre-wet liquid supply body, in addition to the effect of the first aspect of the invention, an image support is provided if necessary. It is possible to provide a liquid developing method for an electrostatic latent image in which it is easy to apply the pre-wetting liquid on the body.

According to the third aspect of the invention, the pre-wet liquid supply body holds the pre-wet liquid supply body by bringing the pre-wet liquid supply body into contact with the image support body while rotating the pre-wet liquid supply body in a direction opposite to the rotation direction of the image support body. The pre-wet liquid is discharged at the contact start side between the image support and the pre-wet liquid supply member, and is regulated to have a uniform thickness by the contact portion between the image support and the pre-wet liquid supply member. It is possible to provide a liquid developing method for an electrostatic latent image, which can apply the liquid with a uniform thickness.

According to the invention of claim 4, in addition to the effect of the invention of claim 1, the prewetting liquid is obtained by using as the elastic member a continuous porous body having a three-dimensional network structure with continuous pores. Can be supplied to the image support while being held in the pores, and the amount of pre-wet liquid supplied to the image support can be controlled by the pore size and porosity of the pre-wet supply body. A liquid developing method of an image can be provided.

According to the fifth aspect of the present invention, part of the pre-wet liquid supply member is immersed in the pre-wet liquid. It is possible to provide a liquid developing method for an electrostatic latent image that can continuously supply the liquid.

According to the sixth aspect of the invention, by virtue of the above-mentioned constitution, in addition to the effect of the first aspect of the invention, an electrostatic latent image that is well compatible with the liquid developer and the pre-wet liquid is formed. A liquid developing method can be provided.

According to the invention described in claim 7, in addition to the effect of the invention described in claim 6, by virtue of the above-mentioned structure, the electrostatic latent image can be improved in the working environment with less pollution. The liquid developing method can be provided.

According to the invention described in claim 8, by virtue of the above-mentioned constitution, in addition to the above effects, there is provided a liquid developing method for an electrostatic latent image in which toner is easily peeled off during transfer. it can.

According to a ninth aspect of the present invention, by virtue of the above configuration, in addition to the above effects, there is provided a liquid developing method for an electrostatic latent image, which can improve releasability at the time of transfer. Can be provided.

According to the invention described in claim 10, in addition to the above effects, the method for developing a liquid of an electrostatic latent image, which has less pollution and improves the working environment, can be achieved by the above-mentioned structure. Can be provided.

According to the eleventh aspect of the present invention, by virtue of the above-mentioned constitution, it is possible to provide an electrostatic latent image liquid developing device having the same effect as that of the first aspect of the invention.

According to the twelfth aspect of the invention, by virtue of the above construction, it is possible to provide the electrostatic latent image liquid developing device having the same effect as that of the second aspect of the invention.

According to the thirteenth aspect of the invention, by virtue of the above-mentioned constitution, it is possible to provide a liquid developing device for an electrostatic latent image having the same effect as that of the third aspect of the invention.

According to the fourteenth aspect of the invention, by virtue of the above construction, it is possible to provide a liquid developing device for an electrostatic latent image having the same effect as that of the fourth aspect of the invention.

According to the fifteenth aspect of the invention, by virtue of the above construction, it is possible to provide a liquid developing device for an electrostatic latent image having the same effect as that of the fifth aspect of the invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrostatic recording apparatus 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 recording device shown in FIG.

FIG. 3 is a diagram for explaining the operation of the electrostatic recording 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 a flow of the pre-wet liquid when the pre-wet liquid supply body 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 diagram for explaining a soft contact of the present invention.

FIG. 14 is a diagram showing a modified example of the pre-wetting device used in the electrostatic recording apparatus according to the first embodiment of the present invention.

FIG. 15 is a schematic view of a pre-wetting device used in the electrostatic recording device according to the second embodiment of the present invention.

16 is a schematic view of a pre-wet liquid supply body used in the pre-wetting device shown in FIG.

FIG. 17 is a diagram showing a modified example of the pre-wetting device used in the electrostatic recording apparatus according to the second embodiment of the present invention.

FIG. 18 is a diagram showing a modified example of the pre-wet supply body used in the electrostatic recording apparatus according to the second embodiment of the present invention.

[Explanation of symbols]

 10 Photoconductor 20, 22, 2480 Pre-wet device 30 Charging device 40 Exposure device 50 Developing device 60 Transfer device 70 Cleaning device 202, 222, 802 Pre-wet liquid supply body 204, 804 Case 206, 224, 244, 806 Tank 208, 226, 504, 808 Pumps 210a, 210b, 228, 810 Pipe lines 212 Separating / connecting devices 213a, 213b Shafts 214a, 214b Cams 215a, 215b Spring 230 Guide 232 Liquid receiving 502 Developing tank 506 Developing roller 510 Layer forming roller 520 Developing belt 602 Transfer roller 702 Fixing roller 704 Fixing heater

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Tanaka 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 method for an electrostatic latent image, which is developed with toner that is a charged image-forming particle, and a pre-wetting liquid that is a dielectric liquid that is releasable and chemically inert prior to the developing process. The pre-wet liquid supply body formed of a member having liquid permeability and liquid retention property is impregnated, and the pre-wet liquid supply body is brought into contact with the image support body, thereby pre-wetting on the image support body. A pre-wetting step of applying a liquid, and a high-viscosity liquid developer of 100 to 10000 mPa · s in which the toner is dispersed in high concentration in the insulating liquid applied on the developer support is applied to the image support. A developing step of supplying the liquid developer to the latent image surface of the image support by bringing it into contact with the latent image surface, and a liquid developing method for an electrostatic latent image. 2. The liquid developing method for an electrostatic latent image according to claim 1, wherein the pre-wet liquid supply body is formed in a plate shape. 3. The pre-wetting step brings the pre-wet liquid supply body into contact with the image support while rotating the pre-wet liquid supply body in a direction opposite to the rotation direction of the image support, thereby causing the pre-wet liquid supply body to contact the image support on the image support. The liquid developing method for an electrostatic latent image according to claim 1, wherein a pre-wetting liquid is applied. 4. The liquid developing method for an electrostatic latent image according to claim 1, wherein the member is a continuous porous body having a three-dimensional network structure with continuous pores. 5. The liquid developing method for an electrostatic latent image according to claim 1, 2, 3 or 4, wherein a part of the prewetting liquid supply body is immersed in the prewetting liquid. 6. The liquid developer has an insulating liquid having a viscosity of 0.5 to 1000 mPa · s and an electric resistance of 10 ¹² Ωcm.
As described above, the surface tension is 21 dyn / cm or less and the boiling point is 100.
It is above ° C, Claims 1, 2, 3, 4
Or the liquid developing method for an electrostatic latent image according to item 5. 7. A liquid developing method for an electrostatic latent image according to claim 6, wherein the liquid developer uses silicon oil as an insulating liquid. 8. The liquid developer has an average particle size of 0.1 to 5
The liquid developing method for an electrostatic latent image according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that it contains a toner having a particle size of 5 µm at a concentration of 5 to 40%. 9. The pre-wetting liquid has a viscosity of 0.5 to
5 mPa · s, electric resistance 10 ¹² Ωcm or more, boiling point 1
5. The surface tension is 0 to 250 ° C. and the surface tension is 21 dyn / cm or less.
7. A liquid developing method for an electrostatic latent image according to 7 or 8. 10. The pre-wet liquid contains silicon oil as a main component.
A liquid developing method for an electrostatic latent image as described above. 11. A liquid developing device for an electrostatic latent image, which develops an electrostatic latent image formed on an image support with toner, which is a charged image-forming particle, having a releasing property and a chemical property. Of the image by contacting the pre-wet liquid supply member formed of a liquid-permeable and liquid-retaining member impregnated with a pre-wet liquid, which is an electrically inactive dielectric liquid, with the image support. Prewetting means for applying the prewetting liquid on a support, and a high-viscosity liquid developer of 100 to 10000 mPa · s in which toner is dispersed in high concentration in an insulating liquid applied on a developer support. And a developing means for supplying the liquid developer to the latent image surface of the image support by bringing the liquid developer into contact with the image support. 12. The liquid electrostatic latent image developing device according to claim 11, wherein the pre-wet liquid supply body is formed in a plate shape. 13. The pre-wetting means brings the pre-wet liquid supply body into contact with the image support while rotating the pre-wet liquid supply body in a direction opposite to the rotation direction of the image support, thereby allowing the pre-wet liquid supply body to contact the image support on the image support. The liquid developing device for an electrostatic latent image according to claim 11, wherein a pre-wetting liquid is applied. 14. The liquid developing device for an electrostatic latent image according to claim 11, 12 or 13, wherein the member is a continuous porous body having a three-dimensional network structure with continuous pores. 15. A liquid developing device for an electrostatic latent image according to claim 11, 12, 13 or 14, wherein a part of the pre-wet liquid supply body is immersed in the pre-wet liquid.