JP2001290372A - Wet developing device and wet image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet developing device small in size and capable of obtaining high-quality printing while developing a latent image with a toner layer having a high solid component ratio corresponding to the concentration fluctuation of liquid developer in a wide range. SOLUTION: This developing device is equipped with the liquid developer 21, a liquid developer reservoir part 22, a developer carrier 24 carrying the low-density liquid developer 21 to the latent image formed on a latent image carrier 11 so as to develop the latent image, a developer supplying body 25 supplying the liquid developer 21 to the carrier 24 and forming electric field with the carrier 24, a voltage source 26 for giving potential to the carrier 24, and a voltage source 27 for giving potential to the supply body 25. By using the high-concentration liquid developer 21 and forming electric field by which toner particles in the liquid developer 21 between the carrier 24 and the supply body 25 receive force toward the supply body 25, the desired low-density liquid developer 21 layer is formed on the surface of the carrier 24 and carried to the image carrier 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet developing apparatus and a wet image forming apparatus, and more particularly to a liquid developing apparatus comprising a latent image formed on a latent image carrier and a liquid carrier in which toner is dispersed. 1. Field of the Invention The present invention relates to a wet developing device for developing using a wet developing device and a wet image forming apparatus using the wet developing device.

[0002]

2. Description of the Related Art Conventionally, a latent image formed on a latent image carrier is developed by a wet developing device using a liquid developer in which a toner is dispersed in a liquid carrier, so that the toner image is carried on the latent image carrier. 2. Description of the Related Art There is known a wet developing device which forms an image on a body and transfers the toner image to form an image.

In this wet developing apparatus, toner is adhered to the surface of the latent image carrier during development, and toner is transferred from the surface of the latent image carrier to the transfer material during transfer.
The phenomenon called electrophoresis of toner particles charged by a liquid carrier is used.

In order to obtain a high-quality image in a short time, it is important to use a liquid developer having an appropriate concentration. For this purpose, a high-concentration liquid is usually used by forming a desired high-concentration liquid developer layer by using an electric field using a low-concentration liquid developer, storing an appropriate concentration of the liquid developer, and using the liquid developer. Methods such as using a developer diluted with a diluting liquid and using a high-concentration liquid developer itself are employed.

A technique for forming a desired high-concentration liquid developer layer by using an electric field using a low-concentration liquid developer is described in Japanese Patent Application Laid-Open No. Hei 8-297417. Here, a voltage is applied to a roller corresponding to the developer supply, and toner particles in the liquid developer are moved to form a high-concentration liquid developer layer on the roller surface corresponding to the developer supply. A high-concentration liquid developer layer is formed on the surface of the developer carrier by a voltage applied to the roller corresponding to the developer carrier, and the liquid developer layer is conveyed to a photosensitive drum as a latent image carrier. And develop the latent image.

[0006]

The above-described conventional wet developing apparatus has the following problems.

A first problem is that a desired high-concentration liquid developer layer is formed by an electric field using a low-concentration liquid developer, or an appropriate low-concentration liquid developer is stored and used in advance. In the method of using a high-concentration liquid developer diluted with a diluting liquid, it is necessary to use a low-concentration liquid developer as the liquid developer in the reservoir or to prepare a large amount of diluting liquid separately from the liquid developer. Therefore, the volume of the liquid developer reservoir becomes large, and the device becomes large.

A second problem is that, in a method in which a high-concentration liquid developer is prepared in the liquid developer reservoir and the high-concentration liquid developer is used as it is, the high-concentration liquid developer has a high viscosity.
Since the charge amount is not appropriate, the toner also adheres to the non-image portion to cause fogging, and it is difficult to obtain a desired image density in the image portion.

The third problem is that the method using the liquid developer of a low concentration or a high concentration as it is has no means for keeping the concentration of the liquid developer constant, so that the viscosity and the charge amount of the liquid developer change. However, the print quality is degraded due to fluctuations in the developer concentration in the liquid developer reservoir.

SUMMARY OF THE INVENTION An object of the present invention is to form an appropriate low-concentration liquid developer layer using a high-concentration liquid developer and perform development, thereby miniaturizing the apparatus and changing the concentration of the liquid developer over a wide range. Accordingly, it is an object of the present invention to provide a wet developing apparatus and a wet image forming apparatus which obtain high quality printing while developing a toner layer having a high solid content ratio on a latent image.

[0011]

In order to develop a latent image on a latent image carrier with a toner, the liquid developing device of the present invention transfers the liquid developer from a liquid developer reservoir containing a liquid developer. In the wet developing device for transporting to the latent image carrier, the concentration of the liquid developer transported to the latent image carrier is lower than the concentration of the liquid developer in the liquid developer reservoir.

In the wet developing device according to the present invention, a developer carrier for conveying the liquid developer to the latent image carrier, and the liquid developer is supplied to the developer carrier from the liquid developer reservoir. A developer supply unit, wherein the electric field is formed such that the toner particles in the liquid developer receive a force from the developer carrier toward the developer supply unit.

According to the wet developing device of the present invention, the rotation speed and the rotation direction of the developer carrier and the developer supply member are selected so that the distance between the developer carrier and the developer supply member is increased. The supply amount of the liquid developer may be controlled.

In the wet developing device according to the present invention, a diluting liquid is injected between the developer carrying member and the developer supplying member, and a liquid developer layer having a lower concentration than that in the liquid developer reservoir is formed. It may be characterized in that it is formed on an agent carrier.

In the wet developing device according to the present invention, a diluting liquid is injected into a region between the developer carrying member and the developer supplying member where the electric field works effectively, and the concentration of the diluting liquid is lower than that in the liquid developer reservoir. The liquid developer layer may be formed on the developer carrier.

In the wet image forming apparatus of the present invention, in order to develop the latent image on the latent image carrier with toner, the liquid developer is transferred from the liquid developer reservoir containing the liquid developer to the latent image carrier. In the wet image forming apparatus, the concentration of the liquid developer to be conveyed to the latent image carrier is lower than the concentration of the liquid developer in the liquid developer reservoir.

The wet image forming apparatus according to the present invention comprises a developer carrier for transporting the liquid developer to the latent image carrier, and supplying the liquid developer to the developer carrier from the liquid developer reservoir. And an electric field that causes the toner particles in the liquid developer to receive a force from the developer carrier toward the developer supply member.

According to the wet image forming apparatus of the present invention, the rotation speed and the rotation direction of the developer carrier and the developer supply member are selected so that the developer carrier and the developer supply member can be connected to each other. The supply amount of the liquid developer during the period may be controlled.

In the wet image forming apparatus of the present invention, a diluting liquid is injected between the developer carrying member and the developer supplying member to form a liquid developer layer having a lower concentration than that in the liquid developer reservoir. It may be characterized in that it is formed on a developer carrier.

In the wet image forming apparatus according to the present invention, a diluting liquid is injected into a region between the developer carrying member and the developer supplying member where the electric field works effectively. A liquid developer layer having a high concentration may be formed on the developer carrier.

[0021]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a wet image forming apparatus of the present invention. The wet image forming apparatus is used for image formation of a printer, a copying machine, a facsimile, and the like.

The latent image carrier 11 is rotated at a constant speed in the direction of the arrow at the time of image formation by driving a motor (not shown). After being uniformly charged by the main charger 13, the electrostatic latent image is transferred to the latent image carrier 11 by the exposure device 14.
Formed and carried on top. Thereafter, the electrostatic latent image passes through the wet developing device 15 and is developed into a toner image. An auxiliary charger 16 is arranged after the wet developing device 15. Thereafter, the toner image on the latent image carrier 11 is transferred to a sheet 18 via an intermediate transfer unit 17 and fixed by a fixing unit 19. The paper 18 is supplied to the intermediate transfer unit 1 by a paper feeding unit (not shown).
The sheet is conveyed between the fixing device 7 and the fixing device 19 and is discharged out of the wet image forming apparatus by a discharge unit (not shown).

In this embodiment, four sets of the exposure device 14, the wet developing device 15, and the auxiliary charging device 16 are arranged.
This is to obtain a full-color image by developing four colors of yellow, magenta, cyan, and black. The development of the present invention is not limited to four colors. It may be a single color.

FIG. 2 is a schematic configuration diagram of the wet developing device 15 and the latent image carrier 11 according to the first embodiment of the present invention. Referring to FIG. 2, the wet developing device 15 transports and develops the liquid developer 21, the liquid developer reservoir 22, and the low-density liquid developer 21 to the latent image formed on the latent image carrier 11. Developer carrying member 24 for causing
Developer supply member 25 for supplying liquid developer 21 to developer supply member and forming an electric field between developer supply member 24, voltage source 26 for applying potential to developer support member 24, and developer supply member A voltage source 27 for applying a potential to the cleaning blade 25; and a cleaning blade 2 for scraping off the deposits on the developer carrier 24.
8, a cleaning blade 29 for scraping off the deposits on the developer supply 25, and a stirrer 30 for stirring the liquid developer 21 in the collected liquid developer reservoir 22.

Next, the operation will be described. While the traveling of the latent image carrier 11 is in the direction of the arrow shown in FIG. 2, the developer carrier 24 and the developer supply 25 are rotated in the direction shown by the arrow in FIG. That is, the developer carrier 24 is rotated in the same direction as the latent image carrier 11 at a tangential portion, and the developer supply member 25 is rotated in the opposite direction to the developer carrier 24.

At this time, the difference between the peripheral speed of rotation of the developer supply member 25 with respect to the developer support member 24 causes the developer support member 24 to rotate.
The supply amount of the liquid developer 21 to the liquid can be controlled. When increasing the supply amount of the liquid developer 21 to the developer carrying member 24, the rotation speed of the developer supplying member 25 is increased.

The developer supply member 25 controls the developer carrier 2
For example, when the toner particles in the liquid developer 21 supplied between the developer carrier 4 and the toner carrier 4 have a positive polarity, the toner particles have a positive polarity by forming an electric field from the developer carrier 24 to the developer supply body 25. The particles are supplied to the developer supply 25 by an electric field.
, The liquid developer 2 having a lower concentration than the liquid developer 21 in the liquid developer reservoir 22 on the developer carrier 24.
One layer is formed.

According to the present embodiment, the high-density liquid developer 2 is stored in the liquid developer reservoir 22 without using the diluting liquid.
1 can be used, which leads to downsizing of the entire apparatus, and further controls the electric field between the developer carrying member 24 and the developer supplying member 25 and the peripheral speed difference of rotation of the developer supplying member 25 with respect to the developer carrying member 24. By doing so, a wide range of liquid developer 21
It is possible to obtain the liquid developer 21 having an appropriate concentration on the developer carrying member 24 with respect to the density fluctuation.

The method of controlling the peripheral speed difference of the rotation of the developer supply member 25 with respect to the developer carrier 24 with respect to the concentration fluctuation of the liquid developer 21 and the electric field between the developer supply member 25 and the developer carrier 24 are as follows. A concentration sensor or the like is provided in the liquid developer reservoir 22, and an electric field and a rotation speed condition for forming the liquid developer 21 having a desired concentration from the high concentration liquid developer 21 are obtained in advance, and the liquid development is performed according to the data. A method of determining the electric field and the rotation speed with respect to the concentration of the agent 21 can be considered.

In response to the concentration fluctuation of the liquid developer 21, the layer of the liquid developer 21 formed on the developer carrier 24 has a gradient such that the concentration becomes higher toward the surface layer due to the electric field. An image can be developed with a toner layer having a high solid content ratio, and there is also an effect that excess carrier liquid after development on the latent image carrier 11 is easily removed.

The developer supply 25 and the developer carrier 2
The rotation direction of the developer supply member 4 and the rotation direction of the developer carrier 24 are not limited to the above. Any of them are conceivable. Further, by selecting the combination of the rotation directions, the supply amount of the liquid developer between the developer carrier 24 and the developer supply member 25 can be controlled. A wide range and high-precision control becomes possible.

Next, a second embodiment of the present invention will be described. FIG. 3 is a schematic configuration diagram of the wet developing device 15 and the latent image carrier 11 according to the second embodiment of the present invention. In the second embodiment, a diluting liquid reservoir 32 is provided separately from the liquid developer reservoir 22 of the first embodiment. The dilution liquid reservoir 32 contains the dilution liquid 31.

The operation of the second embodiment will be described. The diluent liquid 31 is supplied to a region where the electric field between the developer carrier 24 and the developer supply member 25 works effectively. Thereby, the liquid developer 21 by the electric field forming means of the first embodiment is used.
Can be reduced.

As a method of supplying the diluting liquid 31, the diluting liquid 31 is pumped from the diluting liquid reservoir 32 to the developer carrier 24 by a pump or the like, and the diluting liquid 31 is transported to a region where the electric field works effectively. Conceivable.

[0035]

As described above, the present invention requires a means for diluting a high-concentration liquid developer when a desired low-concentration liquid developer is formed on a developer carrier from a high-concentration liquid developer. Since there is no or only a small amount, there is an effect that the size of the liquid developer reservoir can be reduced and the size of the entire apparatus can be reduced.

The liquid developer layer formed on the developer carrier has a gradient such that the density increases toward the surface layer due to the electric field. There is an effect that the liquid is easily removed.

Further, a developer supply unit is used as means for controlling the supply amount of the liquid developer to the developer carrier, and the supply amount is determined by the peripheral speed difference and the rotation direction of the developer supply unit with respect to the developer carrier. Since controllable, the supply amount of the liquid developer to the developer carrier can be easily controlled.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a wet image forming apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of a first embodiment.

FIG. 3 is a schematic configuration diagram of a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 latent image carrier 13 main charger 14 exposure device 15 wet developing device 16 auxiliary charger 17 intermediate transfer device 18 paper 19 fixing device 21 liquid developer 22 liquid developer reservoir 24 developer carrier 25 developer supply member 26 Voltage source 27 Voltage source 28 Cleaning blade 29 Cleaning blade 30 Stirrer 31 Diluted liquid 32 Diluted liquid reservoir

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomoyuki Yoshii 5-7-1 Shiba, Minato-ku, Tokyo Within NEC Corporation (72) Inventor Atsushi Otatsu 7546 Yasuda, Oji, Kashiwazaki-shi, Niigata Niigata Nippon Electric In-house (72) Inventor Tsutomu Uesono 5-7-1 Shiba, Minato-ku, Tokyo F-term within NEC Corporation 2H074 AA03 BB16 CC03 CC21 CC22 EE07

Claims (10)

[Claims] 1. A wet developing device for conveying a liquid developer from a liquid developer reservoir containing a liquid developer to the latent image carrier in order to develop a latent image on the latent image carrier with toner, A liquid developing device, wherein the concentration of the liquid developer conveyed to the latent image carrier is lower than the concentration of the liquid developer in the liquid developer reservoir. 2. A developer carrier for conveying the liquid developer to the latent image carrier, and a developer supply unit for supplying the liquid developer from the liquid developer reservoir to the developer carrier. 2. The wet developing apparatus according to claim 1, further comprising an electric field that causes the toner particles in the liquid developer to receive a force from the developer carrier toward the developer supply body. 3. The liquid developer supply between the developer carrier and the developer supply body by selecting a rotation speed and a rotation direction of the developer carrier and the developer supply body. 3. The wet developing device according to claim 2, wherein the amount is controlled. 4. A diluting liquid is injected between the developer carrying member and the developer supplying member, and a liquid developer layer having a lower concentration than in the liquid developer reservoir is formed on the developer carrying member. The wet developing device according to claim 2, wherein the developing is performed. 5. A diluting liquid is injected into a region between the developer carrying member and the developer supplying member where the electric field works effectively, and a liquid developer layer having a lower concentration than that in the liquid developer reservoir is formed. 3. The image forming apparatus according to claim 2, wherein the developer carrier is formed on the developer carrier.
Or a wet developing device according to 3. 6. A wet image forming apparatus for conveying a liquid developer from a liquid developer reservoir containing a liquid developer to the latent image carrier in order to develop a latent image on the latent image carrier with toner. A wet image forming apparatus, wherein the concentration of the liquid developer conveyed to the latent image carrier is lower than the concentration of the liquid developer in the liquid developer reservoir. 7. A developer carrier that conveys the liquid developer to the latent image carrier, and a developer supplier that supplies the liquid developer from the liquid developer reservoir to the developer carrier. 7. The wet image forming apparatus according to claim 6, wherein an electric field is formed such that toner particles in the liquid developer receive a force from the developer carrier toward the developer supply body. 8. The liquid developer supply between the developer carrier and the developer supply by selecting a rotation speed and a rotation direction of the developer carrier and the developer supply. 8. The wet image forming apparatus according to claim 7, wherein the amount is controlled. 9. A liquid developer layer having a lower concentration than in the liquid developer reservoir is formed on the developer carrier by injecting a diluting liquid between the developer carrier and the developer supply body. The wet image forming apparatus according to claim 7, wherein 10. A diluting liquid is injected into a region between the developer carrier and the developer supply member where the electric field works effectively,
9. The wet image forming apparatus according to claim 7, wherein a liquid developer layer having a lower concentration than that in the liquid developer reservoir is formed on the developer carrier.