JPH0546029A - Liquid developing method - Google Patents

Abstract

PURPOSE:To develop even an electrostatic latent image having a potential difference over a wide range without irregularity with a small quantity of developer, and to accurately and rapidly control the supply and the stop of the developer for the electrostatic latent image. CONSTITUTION:This is a developing method in which the liquid developer containing electrostatically charged coloring fine powder which is dispersed in electric insulating non-magnetic liquid is allowed to exist between a rotating photosensitive body supporting body 1 having the electrostatic latent image and a developing roller 2 which comes close to the supporting body and rotates in a reverse direction to the supporting body 1 on a surface close to the roller 2, and the electrostatic latent image is developed by the action of electric field formed between the supporting body 1 and the developing roller 2. In this method, the liquid developer discharged from a liquid supply part provided with a slit whose gap is 10-3000mum is supplied to the supporting body 1 or a gap between the supporting body 1 and the developing roller 2 as a thin film and an area where it is enough to coat the electrostatic latent image therewith.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid developing method for electrophotography, and more particularly to a method for visualizing an electrostatic latent image with a liquid developer in which colored particles are dispersed in an electrically insulating non-polar liquid carrier. Is.

[0002]

2. Description of the Related Art As a method of converting an electrostatic latent image obtained by an electrophotographic method into a visible image, there are a dry developing method and a liquid developing method, but their stability with time, good handling property, odor, etc. Due to problems, the dry developing method is generally used at present. However, the recent demand for higher image quality has re-evaluated the necessity of the liquid developing system. The developer used in the liquid development method is a suspension of colored fine powder in an electrically insulating carrier liquid. Due to its small particle size, fine line reproducibility is better than when other developers are used. Is good
In addition, it is possible to obtain a high-contrast image, and to exhibit its characteristics even in full-color development using four color toners of yellow, magenta, cyan, and black, and to obtain high-resolution and high-gradation image quality This is one of the big reasons.

In general, the liquid development method is used for stabilizing dye and pigment particles such as phthalocyanine blue, azo pigment, carbon black and the like in an electrically insulating non-polar liquid, or fixing an image to a transfer target. A developer formed by suspending particles made of resin for improving performance was used to develop an electrostatic latent image in the developing section, after which excess developer was removed and the toner image was transferred to the transfer section. After that, the toner image is transferred to the transfer target. There are many research reports on a method of supplying a developer to a latent image in the developing section. Among these studies, as a method that allows development to be completed in a short time with a relatively small amount of developer and that the developer can be exchanged relatively easily, a support having an electrostatic latent image and a method close to it can be used. , A developing roller whose proximity surface moves in the opposite direction to the support is used, and the developer is supplied from various types of spray outlets onto the electrostatic latent image or onto the developing roller or into the gap between the two adjacent rollers. A method of doing so is reported in International Patent W0 90/14619.

Generally, in the liquid developing system, a toner having a toner particle uniformly dispersed in a carrier liquid is immersed in a developing solution having a support having an electrostatic latent image, and a toner is generated by an electric field formed between the support and the opposing electrode. The particles move to develop the electrostatic latent image. Therefore, in the direction perpendicular to the traveling direction of the electrostatic latent image, since it is the dipping method, uniform development is performed and a relatively uniform image density can be obtained. However, this method requires a large amount of developer and it is very difficult to develop with different color developers such as color printing. Therefore, development can be completed in a short time with a small amount of developer,
Various methods have been studied for quick replacement of the developing solution, but when reproducing an electrostatic latent image of a relatively low potential, that is, one having a halftone density, it is possible to use a vertical direction with respect to the traveling direction of the electrostatic latent image. There are still many undeveloped methods such as density unevenness that often occurs in the direction, and a method of quickly changing the supply of the developer by controlling the supply and stop in a short time when the developer is supplied to the electrostatic latent image. The problem of resolution remains.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method capable of developing even an electrostatic latent image having a high potential difference with a small amount of a developing solution. Another object of the present invention is to provide a method which makes it possible to accurately and quickly control the supply and stop of the developing solution with respect to the electrostatic latent image.

[0006]

According to a first aspect of the present invention, there is provided a rotating photosensitive member supporting member having an electrostatic latent image, and a rotating member in the vicinity of the supporting member and rotating in a direction opposite to the supporting member at a proximity surface. A developing agent containing a charged colored fine powder dispersed in an electrically insulating non-polar liquid is allowed to exist between the developing roller and the developing roller, and by the action of an electric field formed between the support and the developing roller. In the method of developing the electrostatic latent image, the liquid developer discharged from a liquid supply unit having a slit having a gap of 10 to 3000 μm is formed as a thin film on the support or in the gap between the support and the developing roll. And,
A liquid developing method, characterized in that the electrostatic latent image is supplied to an area sufficient to cover the electrostatic latent image. The invention according to claim 2 of the present application provides a plurality of liquid supplying parts with respect to the photoconductor support. After being movably arranged, the first electrostatic latent image is developed with the first liquid developer supplied from the first liquid supply unit, and then the position of the first liquid supply unit is set to the second liquid supply unit. And a step of developing the second electrostatic latent image with a second liquid developer, the liquid developing method comprising:

The present invention will be described with reference to the drawings. An apparatus relating to the developing method of the present invention comprises a support 1 having an electrostatic latent image and rotating, and a surface close to and close to the support 1. Developing roller 2 that moves in the opposite direction with the developer storage device 3
And a developer supply unit 4 for supplying a developer.
As shown in FIG. 4, the apparatus according to the present invention is further provided with two or more developer supply units 4 and is rotatably movable so that developer of different colors can be continuously supplied to enable full color output. Is.

The support 1 has a photosensitive layer 1a on its surface and is rotatably supported at a constant peripheral speed in a clockwise direction. The developing roller 2 is maintained at a predetermined gap by the photosensitive layer support 1 and the gap holding means 2a, and is rotatably supported in the clockwise direction at the same speed as the photosensitive layer support 1 to develop the charged liquid developer. Biased to do so.

The gap between the support 1 and the developing roller 2 is a disk-shaped plate 2a having a diameter larger than the diameter of the developing roller 2 by about 10 μm to 500 μm, and is installed concentrically at both ends of the developing roller so as to be rotatable independently of the developing roller. However, it is maintained by pressing the disc plate 2a against the support 1.

A gap between the photosensitive layer support 1 and the developing roller 2,
Alternatively, in order to develop the electrostatic latent image held by the photosensitive layer support 1 on the photosensitive layer support 1 in the vicinity of this gap, a thin film is formed from the slit of the developing solution discharge port 5 of the developing solution supply unit 4. Supply the developing solution to. The gap between the slits of the discharge port 5 is 10 to 30.
It is 00 μm. The developing solution is ejected in a thin film form from the slit of the ejection port 5 and comes into contact with the rotating photoreceptor support 1 to cover the latent image and develop the latent image. The liquid developer used in the present invention is a dispersion of colored toner particles formed with a known composition in a carrier liquid having a volume resistivity of 10 ¹⁰ Ω · cm or more and a dielectric constant of 3.0 or less. The content is adjusted to about 1.5% and a charge-imparting agent is added.
Liquid developer not used for development on the support 1 is scraped off by the roller 9.

The developing solution supply section 4 is provided with at least three developing solution introducing sections 6 in the longitudinal direction, and assists the uniform supply of the solution to the developing solution supply section 4. Further, by providing the shutter 7 in the slit portion 5 and electrically controlling the opening / closing, the supply timing of the developing solution can be controlled.

The developing solution is transferred from the developing solution storage unit 3 to the developing solution supply unit 4 by a power pump. The slit gap of the developer discharge port 5 adjusts the relationship between the developer supply pressure and the slit gap according to the developing speed, and a constant pressure is constantly applied to the developer supply unit 4 so that the developer is filled with the developer.

FIG. 4 is an apparatus showing a four-color full-color developing method. Developer supply parts 4-1, 4-2, 4-3, 4
-4 are arranged in a satellite shape around the rotating shaft 8, and different developing solutions corresponding to the developing solution supply sections are respectively supplied from the developing solution storages 3-1, 3-2, 3-3, 3-4. You can do it.

A full color developing method will be described.
First, a first developing solution (for example, a cyan developing solution) in the developing solution supply unit 4-1 is subjected to a first development, and an image is transferred to a transfer target (not shown) to form a photosensitive layer support 1. The residual toner remaining on the top is removed. The photosensitive layer support 1 rotates toward a portion close to the developing roller 2 while holding the second electrostatic latent image and approaches the developing roller 2. On the other hand, when the discharge of the developing solution is completed, the developing solution supply section 4-1 moves a predetermined distance around the rotating shaft 8, and the developing solution supply section 4-2 moves to the developing solution supply position to carry out the second development. Second with liquid (eg magenta developer)
To develop the electrostatic latent image of. Thereafter, this method is repeated to form a full-color image with two or more color developers.

The transfer means to the transferred material may be a known means, for example, a method using the intermediate transfer roller 10. As a method of removing the residual toner on the photosensitive layer support 1, a scraping method using a blade 12 and a sponge roller 11 may be used.

[0016]

The developing method of the present invention is capable of uniformly developing an electrostatic latent image under a wide range of surface potential conditions, and by controlling the supply of the developing solution with high precision, a variety of different methods can be used. The developer can be continuously developed without being mixed.

Conventionally, in order to uniformly supply a developing solution to an electrostatic latent image and to enable sufficient development even in a low-potential electrostatic latent image, a sufficient gap is provided between the photosensitive layer support and the developing roller. The method of accumulating a certain amount of developing solution and developing it was general.
According to the method of the present invention, it is possible to uniformly supply a necessary amount of the developing solution in the form of a thin film to the electrostatic latent image, and the amount of the solution accumulated in the gap between the photosensitive layer support and the developing roller is sufficient. Less. As a result, the load on the excess liquid removing section after development can be significantly reduced, a desired image can be obtained without the need for an excess liquid removing roller, and further, the developer can be instantaneously replaced. Yes, it has a great advantage in dealing with high speed and multicolor.

[0018]

[Brief description of drawings]

FIG. 1 is a sectional view illustrating a developing method.

FIG. 2 is a front view of a developer supply portion.

FIG. 3A is a front view of a developing solution supply unit, FIG. 3B is a side view of the developing solution supply unit, and FIG. 3C is a bottom view of the developing solution supply unit.

FIG. 4 is a sectional view illustrating a developing method.

[Explanation of symbols]

 1 photoreceptor support 2 developing roller 4 liquid supply section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Waku 2-3-13 Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. An electrically insulating non-polar material is provided between a rotating photoconductor support having an electrostatic latent image and a developing roller which is proximate to the support and rotates in a direction opposite to the support at a proximity surface. In the method of developing the electrostatic latent image by the action of an electric field formed between the support and the developing roller in the presence of a liquid developer containing charged colored fine particles dispersed in a liquid, a gap 10 is formed. The liquid developer discharged from a liquid supply section having a slit of ˜3000 μm is formed as a thin film on the support or in the gap between the support and the developing roll, and enough to cover the electrostatic latent image. A liquid developing method, characterized in that the liquid is supplied to various areas. 2. A plurality of liquid supply units are movably arranged with respect to a photoconductor support, and a first electrostatic latent image is developed by a first liquid developer supplied from the first liquid supply unit. 2. The liquid development according to claim 1, further comprising the step of changing the position of the first liquid supply unit to the second liquid supply unit and developing the second electrostatic latent image with the second liquid developer after the above. Method.