JPH08114987A - Liquid developing device and liquid developing method for electrostatic latent image - Google Patents

Abstract

PURPOSE: To provide a liquid developing device and a liquid developing method for an electrostatic latent image in which working environment can be improved, which have high resolution, and which can be easily miniaturized with low pollution. CONSTITUTION: This liquid developing device for the electrostatic latent image by which the electrostatic latent image formed on a photoreceptor 10 is developed by toner is provided with developing process in which the toner is supplied on the latent image surface of the photoreceptor 10 by bringing a developing belt 510 coated with high-viscosity liquid developer having the toner dispersed in insulating liquid at high concentration into contact with the photoreceptor 10 through the liquid developer, and a moldreleasing layer whose surface energy is smaller than that of the liquid developer is formed on the surface of the photoreceptor 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, there have been liquid developers and powder developers as developers for developing an electrostatic latent image, but in an electrostatic recording apparatus or the like which requires high image quality, the liquid development is usually performed. Agent is used. The reason for this is that the toner particle size of the powder developer is 7 to 10 μm, whereas the toner particle size of the liquid developer is 0.1 to 0.5 μm. Therefore, the liquid developer was used. In this case, it is possible to obtain a high-resolution image as compared with the case where the powder developer is used. Further, since powder generally has poorer fluidity than liquid, powder developer is more difficult to stir than liquid developer, and therefore it is difficult to perform uniform development in a wide range with powder developer. Is.

[0003]

By the way, in a conventional large-sized electrostatic recording device, IsoparG which is generally an organic solvent is used.
(Registered trademark: manufactured by Exxon), a low-viscosity liquid developer in which a toner is mixed at a ratio of about 1 to 2% is used. As described above, since the toner content is small,
Since a large amount of liquid developer is required, it is difficult to downsize the device. Further, IsoparG used as an insulating liquid (carrier liquid) has high volatility and emits a foul odor, so that the conventional device has a problem that not only the working environment is bad but also an environmental problem is caused.

[0004]

The present invention has been made in view of the above circumstances, and is a liquid developing apparatus for an electrostatic latent image which is low in pollution, can improve the working environment, has high resolution, and can be easily downsized, and It is an object of the present invention to provide a liquid developing method.

[0005]

In order to achieve the above-mentioned object, a liquid developing apparatus for an electrostatic latent image according to the present invention described in claim 1 charges an electrostatic latent image formed on an image support. Is a liquid developing device for an electrostatic latent image, which is developed with a toner that is a visualized particle, and a high-viscosity liquid developer of 100 to 10000 mPa · s in which a toner is dispersed in an insulating liquid at a high concentration is applied. A developing means for supplying toner to the latent image surface of the image support by bringing the developer support thus formed into contact with the image support through the liquid developer,
A release layer having a surface energy smaller than that of the liquid developer is formed on the surface of the image support.

According to a second aspect of the present invention, there is provided an electrostatic latent image liquid developing device according to the first aspect, wherein the insulating liquid of the liquid developer has a viscosity of 0.5 to 1,000 mPa · s.
s, electric resistance is 10 ¹² Ωcm or more, surface tension is 21 dy
It is characterized by having a ne / cm or less and a boiling point of 100 ° C. or more.

According to a third aspect of the present invention, there is provided an electrostatic latent image liquid developing apparatus according to the second aspect, wherein the liquid developer uses silicon oil as an insulating liquid. It is what

According to a fourth aspect of the present invention, there is provided an electrostatic latent image liquid developing apparatus according to the first, second or third aspect, wherein the liquid developer is toner having an average particle diameter of 0.1 to 5 μm. It is characterized in that it is contained at a concentration of 5 to 40%.

A liquid developing device for an electrostatic latent image according to a fifth aspect of the present invention is the invention according to the first, second, third or fourth aspect, in which the release layer of the image support is formed of a fluororesin. It is characterized by being.

According to a sixth aspect of the invention, there is provided a liquid developing device for an electrostatic latent image according to the first aspect, wherein the release layer of the image support is made of silicon. It is characterized by being present.

A liquid developing method for an electrostatic latent image according to a seventh aspect of the present invention is an electrostatic latent image for developing an electrostatic latent image formed on an image support with toner which is a charged developing particle. A method for developing a liquid image, wherein a developer support coated with a high-viscosity liquid developer of 100 to 10000 mPa · s in which a toner is dispersed in an insulating liquid at a high concentration is used. A developing step of supplying toner to the latent image surface of the image support by bringing the surface energy of the surface of the image support more than that of the liquid developer. It is characterized in that a small release layer is formed.

[0012]

According to the liquid latent image developing device of the present invention, the liquid developer having a smaller toner particle size than that of the powder developer is used. , You can get high resolution images. Further, by using the liquid developer in which the toner is dispersed at a high concentration, the liquid amount can be much reduced as compared with the case of using the conventional low concentration liquid developer. Further, by using an image support on the surface of which a release layer having a surface energy smaller than that of the liquid developer is formed, the physical adhesion between the liquid developer and the image support is weakened. Since it is possible to prevent the toner from adhering to the non-image portion of the image support, it is possible to prevent the image noise from being generated. The developer has a viscosity of 10
If it is 000 mPa · s or more, it becomes difficult to stir the insulating liquid and the toner, and there is a problem in how to make the developer. Therefore, a liquid developer of 10,000 mPa · s or more becomes unrealistic in terms of cost and becomes unrealistic. On the other hand, if it is 100 mPa · s or less, the toner density becomes low and the dispersibility of the toner becomes poor, so that it becomes impossible to develop the developer in a thin layer.

According to a second aspect of the present invention, there is provided an electrostatic latent image liquid developing device which uses an insulating liquid having the above characteristics.
A high-viscosity liquid developer can be obtained. Since the liquid developer on the developer support is formed into a thin layer, the amount of insulating liquid contained in the liquid developer layer is extremely small.
Therefore, the amount of the insulating liquid contained in the liquid developer supplied to the latent image surface of the image support is very small, and therefore, the amount of the insulating liquid absorbed by the paper or the like at the time of transfer is extremely small. If the viscosity is 1000 mPa · s or less, the problem of the insulating liquid adhering to paper or the like does not occur. However, if the viscosity is 0.5 mPa · s or less, the volatility becomes high and it is not suitable as a hazardous material. 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. When the electric resistance is 10 ¹² Ωcm or less, the insulating property is deteriorated, and the toner has a problem of conductivity and cannot be used as a developer. Therefore, it is desirable that the electric resistance be as high as possible. Surface tension is 21 dyne / cm
When it is more than the above, the wettability becomes poor. Therefore, it is desirable that the surface tension be as low as possible.

In the electrostatic latent image liquid developing device according to the third aspect of the present invention, since the insulating liquid is mainly composed of silicon oil, the insulating liquid having the characteristics of the second aspect can be obtained. it can.

According to a fourth aspect of the present invention, there is provided an electrostatic latent image liquid developing device, wherein 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. In addition, the resolution is improved in almost inverse proportion to the particle size of the toner. Usually, the toner is present as a mass of about 5 to 10 pieces on the printed paper, so that when the average particle diameter of the toner becomes 5 μm or more,
The resolution is poor. On the other hand, the average particle size of the toner is 0.1μ
When it is less than m, the physical adhesion becomes strong, and it becomes difficult to peel off the toner during transfer.

According to a fifth aspect of the present invention, in the electrostatic latent image liquid developing device, the image support has a release layer formed of a fluororesin, so that the image supporting member has a physical adhesive force with the liquid developer. A weak image support can be obtained.

In the electrostatic latent image liquid developing device according to the sixth aspect, since the image support has a release layer formed of silicon, the physical adhesion to the liquid developer is weak. An image support can be obtained.

A liquid developing method for an electrostatic latent image according to a seventh aspect of the invention has the same effect as the invention according to the first aspect.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram of an electrostatic latent image liquid developing device which is an embodiment of the present invention, and FIG. 2 is a diagram for explaining the operation of the electrostatic latent image liquid developing device shown in FIG.

As shown in FIG. 1, an electrostatic latent image liquid developing device 1 according to an embodiment of the present invention includes a photoconductor 10 as an image support, a charging device 30 for charging the photoconductor 10, and a charging device 30 for charging the photoconductor 10. An exposure device 40 that exposes an image on the photoconductor 10 and the photoconductor 10.
Developing device 50 that visualizes the electrostatic latent image by supplying the liquid developer to the portion where the electrostatic latent image is formed, and the toner on the photoconductor 10 is transferred and fixed on a predetermined paper P. The transfer device 60, a cleaning device 70 for removing the liquid developer remaining on the photoconductor 10, and a neutralization device (not shown) for neutralizing the charged photoconductor 10 are provided.

For the charging device 30, the exposure device 40, the cleaning device 70, and the static eliminator, the conventional technique used in the conventional electrophotographic printer can be used in most cases. Therefore, in this embodiment, the description of each of the above devices will be omitted, and the photoreceptor 10, the developing device 50, and the transfer device 60, which are the main parts of the present invention, will be described.

Organophotoreceptor 1 which is the image support of this embodiment
On the surface of No. 0, a release layer made of a material having a surface energy smaller than the surface energy of the liquid developer described later is provided. This is to weaken the physical adhesive force between the liquid developer and the photoconductor 10, which will be described later, to prevent the liquid developer from adhering to the non-image portion of the photoconductor 10. Materials having a surface energy smaller than the surface energy of the liquid developer described later include fluorine resin and silicon.

The developing device 50 includes a developing section 51 and a coating section 5.
2 and. The developing unit 51 includes a developing belt 510, which is a developer support, and driving rollers 512 a and 512 that rotate and drive the developing belt 510 and hold a portion of the developing belt 510 so as to abut against the photoconductor 10.
b, and a scraping blade 514 for removing the liquid developer remaining on the developing belt 510. Application part 5
Reference numeral 2 includes coating devices 52a, 52b, 52c, 52d for coating the surface of the developing belt 510 with the liquid developer.

The developing belt 510 includes a driving roller 512.
The a and 512b rotate the photosensitive member 10 in a direction opposite to the rotating direction. As the developing belt 510, a flexible belt member such as a seamless nickel belt or a resin belt such as a polyimide belt is used. The developing belt 510 must be capable of applying a developing bias. Therefore, when a resin belt is used, it is necessary to reduce the electric resistance value by conducting conductive processing on the belt surface or adding conductive fine particles to the belt material.

The coating devices 52a to 52d store a liquid developer and discharge the liquid developer, and conveying rollers 522a and 522b for conveying the liquid developer discharged by the bellows pump 520 to the developing belt 510.
522c and 522d, and a separation / contact device (not shown) that separates / contacts the conveyance roller 522a from the development belt 510. Bellows pump 520a of the coating device 52a
A liquid developer containing yellow toner is applied to the coating device 5
The liquid developer containing magenta toner is supplied to the bellows pump 520b of the coating device 52c of the 2b.
A liquid developer containing cyan toner is stored in 20c, and a liquid developer containing black toner is stored in the bellows pump 520d of the coating device 52d.

The carrying roller 522d is a carrying roller 522c.
The transport roller 522c is configured to contact the transport roller 5
22b so that it abuts against the transport roller 522b.
Are provided so as to contact the transport rollers 522a. The carrying roller 522d is in the direction opposite to the rotating direction of the developing belt 510, the carrying roller 522c is in the direction opposite to the rotating direction of the carrying roller 522d, and the carrying roller 522b.
Rotates in the direction opposite to the rotation direction of the transport roller 522c, and the transport roller 522a rotates in the direction opposite to the rotation direction of the transport roller 522b.

The transfer device 60 includes an intermediate transfer belt 610, which is an intermediate transfer member, and a drive roller that rotates and drives the intermediate transfer belt 610 and holds a part of the intermediate transfer belt 610 so as to contact the photosensitive member 10. 612a, 61
2b and 612c, and a secondary transfer roller 6 that is a secondary transfer member installed so as to be in contact with the intermediate transfer belt 610.
14 and a scraping blade 616 for removing the toner remaining on the intermediate transfer belt 610.

The intermediate transfer belt 610 includes a driving roller 61.
2a, 612b, and 612c rotate and drive the photoconductor 10 in the opposite direction. Secondary transfer roller 614
Is pressed against the intermediate transfer belt 610 via the paper P.
A fixing heater 618 that heats the paper P is provided inside the drive roller 612c.

Next, the image forming material used in one embodiment of the present invention will be described. The liquid developer used in this example includes a resin that serves as a binder such as epoxy, a charge control agent that gives a predetermined charge to the toner, a color pigment, a toner that includes a dispersant that uniformly disperses the toner, and a carrier liquid. Consists of. The toner composition is basically similar to that used in conventional liquid developers, but their formulation has been modified to be compatible with silicone oils for adjusting charging characteristics and dispersibility. The smaller the average particle diameter of the toner is, the better the resolution is. However, the smaller the particle diameter is, the larger the physical adhesive force is, and it becomes difficult to remove the toner 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 embodiment, the viscosity is 50 to 6000 mPas.
・ S, the toner concentration was changed in the range of 5 to 40% for the experiment.

As the carrier liquid, one having a low viscosity such as dimethylpolysiloxane oil or cyclic polydimethylsiloxane oil exhibiting high electric resistance is used. Incidentally, the developing belt 510
Since the upper liquid developer layer is formed in a thin layer, the carrier liquid contained in the liquid developer layer is extremely small. Therefore, the amount of carrier liquid contained in the liquid developer supplied to the latent image surface of the photoconductor 10 is also extremely small, so that the amount of carrier liquid absorbed by the paper or the like during transfer is extremely small. Therefore, if the viscosity is 1000 mPa · s or less, almost no carrier liquid remains after fixing.

According to the experiments conducted by the present inventors, when the image output experiment was conducted using DC344 of Dow Corning Co., USA having a viscosity of 2.5 mPa · s as the carrier liquid, the carrier remaining on the paper after fixing was determined. No liquid was seen. But,
Due to its high volatility, it was necessary to make the developing device a closed structure. In addition, when the image output experiment was conducted using DC345 of Dow Corning Co., USA, which has a viscosity of 6.5 mPa · s as the carrier liquid, it was fixed on paper after fixing similarly to the case where the image output experiment was conducted using DC344. No carrier liquid remained in the developing solution, but the volatility was so high that the developing device had to have a closed structure. Furthermore, the carrier liquid has a viscosity of 2
Shin-Etsu Silicon KF-96-20 with 0 mPa · s
No carrier liquid remained on the paper after fixing was observed when the image output experiment was carried out using. Further, since the volatility is not so high, it is not necessary to make the developing device have a closed structure. DC344, DC345 and KF-96-
20 is generally used in cosmetics and has high safety such as toxicity. There are many kinds of carrier liquids such as KF9937 manufactured by Shin-Etsu Silicon Co., Ltd., and any one may be selected as long as the electric resistance, the evaporation property, the surface tension, the safety and the like are satisfied.

Further, in an experiment conducted by the present inventors, when the surface tension is large, fogging or a lump of toner occurs on the photoreceptor 10.
21 dyne / cm experimentally
From the above, it was found that the problem of image quality is likely to occur.

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.

Next, the operation of the electrostatic latent image developing device which is an embodiment of the present invention will be described. First, as shown in FIG. 2A, the charging device 30 charges the photoreceptor 10 having a release layer formed on its surface. Generally, the charging device 30 includes
A corona discharger is used. Next, the charged photoreceptor 10
Expose the image on top. 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. 2B, the portion of the laser scanner exposed to the light becomes conductive and the electric charge disappears, and the portion not exposed to the light remains as an electrostatic latent image which is an image of the electric charge.

Next, the electrostatic latent image is visualized by the developing device 50. As shown in FIG. 1, the liquid developer discharged from the bellows pump 520 is conveyed by a plurality of conveying rollers 522a.
It is applied thinly and evenly on the surface of the developing belt 510 via 522d. As a result, a thin layer of the liquid developer is formed on the developing belt 510. The developing device 50 uses one of the coating devices 52a to 5a by a separation / contact device (not shown).
2d is brought into contact with the developing belt 510. As a result, the liquid developer containing any one of the toners of yellow, magenta, cyan, and black can be thinly and evenly applied onto the developing belt 510.

Next, the liquid developer layer formed on the developing belt 510 is brought close to the electrostatic latent image formed on the surface of the photoconductor 10 as shown in FIG. Thus, the charged toner is moved onto the photoconductor 10. As a result, a toner image is formed on the photoconductor 10.

Next, as shown in FIG. 2D, the toner image formed on the photosensitive member 10 is primarily transferred onto the intermediate transfer belt 610 by the transfer device 60. On the other hand, the photoconductor 10
The liquid developer remaining on the photoconductor 10 is removed by the cleaning device 70, and then the charge is removed by a charge removing device (not shown). Then, the coating device 5 that comes into contact with the developing belt 510 by a separation / contact means (not shown)
After switching 2a to 52d, the above-described cycle from charging to static elimination is repeated again, so that yellow, magenta, cyan, and black toner images are transferred one after another onto the intermediate transfer belt 610. As a result, a toner image corresponding to colorization is formed on the intermediate transfer belt 610.

Next, as shown in FIG. 2 (E), the toner image corresponding to the color formed on the intermediate transfer belt 610 by the transfer device 60 is secondarily transferred onto the paper P which is a recording medium and fixed at the same time. Let The toner image corresponding to the color formed on the intermediate transfer belt 610 moves onto the paper P and is secondarily transferred by the pressing force of the secondary transfer roller 614 to the intermediate transfer belt 610 and the heat from the fixing heater 618. At the same time, it is thermally melted and fixed. As a result, the paper P
A color image can be formed on it.

3 to 7 are views for explaining the developing process of one embodiment of the present invention in detail, FIG. 3 is a diagram for explaining the developing process as a whole, and FIG. 4 is an approaching process. FIG. 5 is a diagram showing a state of the toner movement process,
FIG. 6 is a diagram showing the separation process of the non-image part, and FIG. 7 is a diagram showing the separation process of the image part. In the developing process of the present embodiment, as shown in FIG. 3, the developing belt 510 approaches the photoconductor 10 and the liquid developer approaches the surface of the photoconductor 10.
The toner moving process in which the liquid developer layer and the release layer of the photoconductor 10 are in soft contact to move the toner, and the developing belt 510 is separated from the photoconductor 10 and is attached to the developing belt 510 and the photoconductor 10. It is considered that it is composed of three processes, that is, a separation process in which the toner is separated into two particles.

In the approaching process, since the developing belt 510 is made of a flexible belt member, as shown in FIG. 4, the liquid developer layer on the developing belt 510 and the photosensitive member 1 are made.
The contact pressure at the time of contact with the release layer of 0 is dispersed, and the high-viscosity liquid developer including the carrier liquid and the toner is
Soft contact with a release layer of 0.

In the toner moving process, as shown in FIG. 5, in the image portion, the toner on the developing belt 510 is on the latent image surface by the Coulomb force acting between the charge on the photoconductor 10 and the charged toner. Move to and attach. On the other hand, in the non-image portion, the Coulomb force does not act on the charged toner, so the toner on the developing belt 510 does not move to the surface of the photoconductor 10. Further, since a release layer having a surface energy smaller than that of the liquid developer is formed on the surface of the photoconductor 10, the toner is physically attached to the photoconductor 1.
It does not adhere to the surface of 0.

In the separation process, in the non-image part, as shown in FIG.
As shown in, the liquid developer remains on the developing belt 510. Since the surface energy of the release layer is smaller than the surface energy of the liquid developer at the interface between the release layer of the photoconductor 10 and the liquid developer layer, the liquid developer layer physically adheres to the surface of the photoconductor 10. It will not adhere by. On the other hand, in the image area, as shown in FIG. 7, the toner that has moved to the surface of the photoconductor 10 pushes away the carrier liquid. Therefore, the carrier liquid layer is formed on the toner layer. Then, the carrier liquid layer is separated into one that remains on the developing belt 510 and one that moves to the photoconductor 10.

FIG. 8 is a diagram for explaining the significance of thinning the liquid developer. If the liquid developer layer applied on the developing belt 510 is too thick, the viscosity of the liquid developer is high, so that a group of toners that try to move from the developing belt 510 to the surface of the photoconductor 10 by electrostatic force is generated around it. Clusters are formed without cutting off the viscosity of the positioned toner and move to the surface of the photoconductor 10. For this reason, the toner excessively moves, the toner image formed on the photoconductor 10 is disturbed, and image noise occurs. In order to suppress the generation of these clusters, it is necessary to control the layer thickness of the liquid developer layer to a minimum value that allows sufficient development.

FIG. 9 is a diagram showing a state in which a rigid developing roller, which is a developer support, is brought into hard contact with the photoconductor 10, and FIG. 10 is a diagram for explaining the soft contact of this embodiment. . As shown in FIG. 9, when the developing roller and the photoconductor are brought into hard contact with each other, the liquid developer layer is crushed and the toner image formed on the photoconductor 10 is disturbed to cause image noise. Therefore, in this embodiment, as shown in FIG. 10, a developing belt 510 including a flexible belt member is used as a developer support, and the photoconductor 10 and the liquid developer layer on the developing belt 510 are used. The liquid developer layer is prevented from being crushed by dispersing the contact pressure when the and are in contact with each other.

Next, the layer thickness of the liquid developer layer on the developing belt 510 will be described. The thickness of the liquid developer layer on the developing belt 510 is such that the viscosity of the liquid developer is 50 to 100 mP.
It is necessary to reduce the thickness of as or more, particularly 500 mPas or more. Ideally, it should be slightly thicker than the layer thickness that satisfies the toner development amount (that is, the density when solid black is produced) required at the time of development. This is because when a high-viscosity liquid developer is used, the electrostatically selected toner moves to the photoconductor 10 along with the extra toner due to the viscosity of the liquid during development, and therefore, on the photoconductor 10. This is because the toner image formed on the sheet is disturbed. In an experiment conducted by the inventors, a good image was obtained with a layer thickness of about 5 μm for a liquid developer having a high toner concentration and with a layer thickness of about 40 μm for a liquid developer having a low toner concentration. In particular, when a liquid developer having a toner concentration of 20 to 30% is used, the layer thickness of the liquid developer is 8 to 20 μm.
Good image quality was obtained.

As a result of conducting an image forming experiment under the above-mentioned conditions, the optimum range of the viscosity of the liquid developer for the electrostatic latent image developing apparatus of this embodiment is 100 mPa · s to 6000.
It was found to be between mPa · s. The carrier liquid of the liquid developer is DC345 of Dow Corning Inc.
Was used.

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.

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

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

Further, according to the present embodiment, by using the photoconductor 10 on the surface of which the release layer whose surface energy is smaller than that of the liquid developer is formed, the liquid developer and the photoconductor 10 are used. Since it is possible to weaken the physical adhesive force with the toner, it is possible to prevent the toner from adhering to the non-image portion of the photoconductor 10, and thus, image noise such as toner adhering to the non-image portion occurs. Can be prevented.

Alternatively, instead of providing a release layer on the surface of the photoconductor 10, a prewetting liquid, which is a dielectric liquid having releasability and chemically inert, may be applied on the photoconductor 10. The toner can be prevented from adhering to the non-image portion of the photoconductor 10. However, in this case, a pre-wet process for applying a pre-wet liquid to the surface of the photoconductor 10 is required prior to the developing process, and a pre-wetting device for performing this process is required. Therefore, according to this embodiment, as compared with the case where the pre-wet process is performed,
It is possible to reduce the size of the device and reduce the running cost.

The present invention is not limited to this embodiment, and various modifications can be made within the scope of the invention. For example, in this embodiment, the organic photoreceptor 1 is used as the image support.
Although the case of using 0 has been described, the present invention is not limited to this. If the image support has a release layer whose surface energy is smaller than that of the liquid developer on the surface, various photoreceptors used in the Carlson method or electrostatic latent images such as ionography can be used. An electrostatic recording paper such as an electrostatic plotter in which an insulating layer is formed on a conductor formed directly may be used.

Further, in the present embodiment, as the coating device, the one in which the liquid developer is coated on the developing belt 510 via the plurality of conveying rollers 522a to 522d has been described, but the present invention is not limited to this. However, any method may be used as long as it can form a thin liquid developer layer on the developing belt 510. For example, a thin liquid developer layer may be formed on the developing belt 510 by controlling the layer thickness of the liquid developer applied on the developing belt 510 with a rubber or rigid blade.

Further, a coating device 52a for coating the developing belt 510 with a liquid developer containing yellow toner, a coating device 52b for coating the developing belt 510 with a liquid developer containing magenta toner, and a cyan toner. A coating device 52c for coating the developing belt 510 with the liquid developer,
The liquid developer containing black toner is applied to the developing belt 510.
Although the one including the coating device 52d for coating the above is described, the present invention is not limited to this. It suffices if at least one coating device for coating the liquid developer containing the toner of a desired color on the developing belt 510 is provided as necessary.

Further, in this embodiment, the developing belt 5 composed of a flexible belt member as the developer support.
However, the present invention is not limited to this. The developer support may be an elastic roller formed of an elastic member or a rigid roller formed of a conductive member such as metal. However, in order to bring the rigid roller and the image support into contact without crushing the liquid developer layer formed on the rigid roller, an image support belt composed of a flexible belt member is used for the image support. Alternatively, it is necessary to install the rigid roller so that a minute gap or gap is formed between the rigid roller and the image support.

Further, in this embodiment, as a transfer device, the toner image formed on the photosensitive member 10 is primarily transferred onto the intermediate transfer belt 610 which is an intermediate transfer member, and then primary transferred onto the intermediate transfer belt 610. Although the toner image is secondarily transferred onto the paper P to form an image on the paper P, the present invention is not limited to this. The transfer device may be any device capable of transferring the toner image formed on the image support to a recording medium. For example, in a monochrome liquid developing device, the toner image formed on the image support is transferred. It may be directly transferred onto a recording medium without primary transfer onto an intermediate transfer member.

Further, the present invention is not limited to this embodiment, as long as the layer thickness of the liquid developer is 5 to 40 μm.
The viscosity of the liquid developer may be 10,000 mPa · s. At present, since it is difficult to stir the carrier liquid and the toner with a high-viscosity developer of 6000 mPa · s or more,
It is considered that the cost will not be met, but if it becomes available at a low cost, it may be 6000 mPa · s or more. However, 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.

[0059]

As described above, according to the first aspect of the present invention, a high-viscosity liquid developer in which toner is dispersed in a high concentration is developed in a thin layer to develop a high-resolution and downsizing. It is easy, and it is possible to reduce pollution.
By using the image support having the release layer having the above-mentioned configuration on the surface, it is possible to prevent the toner from adhering to the non-image portion of the image support, which causes image noise. It is possible to provide a liquid developing device for an electrostatic latent image capable of preventing the above.

According to the second aspect of the invention, by virtue of the above-mentioned constitution, in addition to the effect of the first aspect of the invention, a liquid developing device for electrostatic latent image having good wettability of the liquid developer is provided. Can be provided.

According to the invention of claim 3, by virtue of the above construction, in addition to the effect of the invention of claim 2, there is little pollution, and an electrostatic latent image capable of improving the working environment can be achieved. It is possible to provide the liquid developing device.

According to the invention described in claim 4, in addition to the effect of the invention described in claim 1, with the above structure, the liquid developing device for an electrostatic latent image in which the toner is easily peeled off at the time of transfer. Can be provided.

According to the invention of claim 5, since the image support has a release layer formed of a fluororesin, an electrostatic latent image having the same effect as that of the invention of claim 1 is obtained. An image liquid developing device can be provided.

According to the invention of claim 6, the image support has a release layer formed of silicon, and thus an electrostatic latent image having the same effect as that of the invention of claim 1 is obtained. A liquid developing device can be provided.

According to the invention described in claim 7, with the above-mentioned constitution, it is possible to provide a liquid developing method of an electrostatic latent image having the same effect as that of the invention described in claim 1.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining the operation of the liquid latent image developing device shown in FIG.

FIG. 3 is a diagram for explaining the entire developing process.

FIG. 4 is a diagram showing a state of an approaching process.

FIG. 5 is a diagram showing a state of a toner movement process.

FIG. 6 is a diagram showing a separation process of a non-image portion.

FIG. 7 is a diagram showing a process of separating an image portion.

FIG. 8 is a diagram for explaining the significance of thinning the liquid developer.

FIG. 9 is a diagram showing a state in which a developing roller and a photoconductor are in hard contact.

FIG. 10 is a diagram for explaining soft contacts of the electrostatic latent image liquid developing apparatus according to the present embodiment.

[Explanation of symbols]

10 Photoreceptor 30 Charging Device 40 Exposure Device 50 Developing Device 51 Developing Unit 52 Coating Part 52a, 52b, 52c, 52d Coating Device 60 Transfer Device 70 Cleaning Device 510 Developing Belt 512a, 512b, 612a, 612b, 612c
Drive roller 514, 616 Scraping blade 520a, 520b, 520c, 520d Bellows pump 522a, 522b, 522c, 522d Conveying roller 614 Secondary transfer roller 618 Heater

Claims (7)

[Claims] 1. 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 developing particle, wherein the toner is high in an insulating liquid. 100 to 1 dispersed in concentration
A developer support coated with a high-viscosity liquid developer of 0000 mPa · s is brought into contact with the image support via the liquid developer to supply toner to the latent image surface of the image support. A liquid developing device for an electrostatic latent image, comprising a developing means, wherein a release layer having a surface energy smaller than that of the liquid developer is formed on the surface of the image support. 2. The liquid developer, wherein the insulating liquid has a viscosity of 0.5 to 1000 mPa · s and an electric resistance of 10 ¹² Ωcm.
Above, surface tension is 21 dyne / cm or less and boiling point is 10.
The liquid developing device for an electrostatic latent image according to claim 1, wherein the temperature is 0 ° C or higher. 3. The liquid developing device for an electrostatic latent image according to claim 2, wherein the liquid developer uses silicon oil as an insulating liquid. 4. The liquid developer has an average particle size of 0.1 to 5
4. The electrostatic latent image liquid developing device according to claim 1, wherein the liquid developing device contains a toner of .mu.m at a concentration of 5 to 40%. 5. The release layer of the image support is formed of a fluororesin.
Or a liquid developing device for an electrostatic latent image according to item 4. 6. A liquid developing device for an electrostatic latent image according to claim 1, wherein the release layer of the image support is made of silicon. 7. A liquid developing method for an electrostatic latent image, which comprises developing an electrostatic latent image formed on an image support with toner, which is a charged image-forming particle, wherein the toner is high in an insulating liquid. 100 to 1 dispersed in concentration
A developer support coated with a high-viscosity liquid developer of 0000 mPa · s is brought into contact with the image support via the liquid developer to supply toner to the latent image surface of the image support. A liquid developing method for an electrostatic latent image, comprising a developing step, wherein a release layer having a surface energy smaller than that of the liquid developer is formed on the surface of the image support.