JPH0145067B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device used for developing electrostatic recording.

2. Description of the Related Art Conventionally, developing devices used in electrostatic recording devices that develop electrostatic latent images into visible images and electrophotographic devices using the same can be broadly classified into dry developing methods and wet developing methods.

Among the dry developing methods, there is a two-component developing method, and the two-component developing method is a method in which toner is charged by mixing a carrier and toner, and development is performed by balancing the charge with an electrostatic latent image. This method has good image quality, is most commonly used in low-speed to high-speed copying machines, and is technically established. However, a toner concentration control mechanism is required to maintain a constant mixing ratio of toner and carrier, and the carrier reaches the end of its life during mixing, making it necessary to periodically replace it. The one-component development method does not require a carrier, nor does it require toner density control or developer replacement, but the image quality is poor and the paper must be specially treated to have high resistance. On the other hand, the wet development method uses Isopar solution, which is a petroleum-based solution, so it must be handled with great care, but the image quality is good. However, it is difficult to print with high density, and if the paper is not selected,
There are drawbacks such as problems with image quality.

The present invention solves the above problems, eliminates the need for toner concentration control, only replenishes the developer regardless of the lifespan of the developer, and uses non-hazardous and non-polluting water-soluble or organic solvents. To provide a liquid developing device which develops an electrostatic latent image with a developing solution, maintains an image quality equivalent to that of gravure printing, and can print on any paper.

In the present invention, a sleeve having a large number of conductive acicular bristles on its surface is rotatably installed by being partially immersed in a conductive developer filled in a tank. The developing device is characterized in that the tips of the conductive acicular bristles on the sleeve surface face the photoreceptor of the developing device without coming into contact with it, and a bias voltage is applied to the sleeve.

Next, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, the surface of a photoreceptor 1 is charged with an electric charge by a charger 2 using corona discharge. Next, when the original 3 is exposed onto the surface of the photoreceptor by the exposure system 4, a latent image of the original 3 is formed on the surface of the photoreceptor. When the latent image passes through the developing device 5 according to the present invention, the developing solution flies due to the force of the electrostatic field and adheres to the latent image surface of the photoreceptor 1, forming a visible image. On the other hand, the paper from the hopper 6 is fed in a synchronized manner so that it can be transferred by the transfer device 7, and the visible image formed on the surface of the photoreceptor is transferred to the charged paper by the transfer device 7 using electrostatic force. Twist and transcribe. However, the visible image on the surface of the photoreceptor is not entirely transferred and is cleaned by the cleaning mechanism 8. Next, the charge remaining on the surface of the photoreceptor is removed by the charge removal light from the charge remover 9, and the development process is completed.

FIG. 2 is a sectional view of the developing device according to the present invention.
In FIG. 2, a brush is constructed by implanting numerous conductive acicular bristles on the surface of a sleeve 11, and the sleeve 11 is connected to a tank 1 filled with a conductive developer 10.
The brush is rotatably disposed in the developer 10, and the brush is immersed in the developer 10, and the developer 10 is held by the acicular bristles of the brush. Further, the brush and the photoreceptor 1 are brought close to each other and faced to each other without contacting each other. Also, sleeve 1
1, a bias voltage V is applied, and the voltage V is varied depending on the developing conditions. Note that stainless steel material, carbon fiber, or the like is used as the needle-like bristles.

3a and 3b are schematic diagrams showing the principle of development in the embodiment of FIG. 2. FIG. Photoreceptor 1 and sleeve 11
It rotates with a relative speed. As the latent image on the photoreceptor 1 and the sleeve 11 gradually approach each other,
As shown in FIG. 3a, the developer 10 filled in the acicular bristles is attracted to the surface of the photoconductor by the force of the electrostatic field generated between the photoconductor 1 and the acicular bristles of the brush. try Furthermore, as the latent image on the photoreceptor approaches the acicular bristles of the brush, the electrostatic field becomes even stronger as shown in Figure 3b, and the developer overcomes its own viscosity, surface tension, and gravity and moves toward the surface of the latent image. fly to and attach to
A visible image is formed. It is also possible to control the density of the visible image by varying the bias voltage V to control the strength of the electrostatic field.

Next, the circumferential speed of the photoconductor is 3 to 85 cm/sec, the relative speed to the sleeve 11 is about 0 to 3, the gap between the photoconductor and the acicular bristles of the brush is 0.3 to 1.5 mm, and the length of the acicular bristles of the brush is 0.3 to 1.5 mm. As a result of developing experiments with 1 to 8 mm,
A good image was obtained. The developing solution may be either water-based or oil-based, and the resistance value was selected to be approximately 10 ⁸ Ω-cm or less. If the viscosity is high, it is unsuitable for high-speed development, and if the surface tension is high, it is unsuitable for high-speed development.

As explained above, according to the present invention, a conductive developer is used as a developer, the developer is held by a conductive brush, and the charge by a bias voltage is concentrated on the tip of the conductive acicular bristles. By flying the droplets, the droplets can be miniaturized and a high-quality visible image can be developed on the photosensitive drum. In addition, toner concentration control is not required, only developer solution needs to be replenished, and the paper can be used without being processed. Furthermore, by rotating the brush relative to the photoreceptor, it has an effect that can be applied to high-speed printing models.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a copying machine to which the developing device of the present invention is applied, Fig. 2 is a sectional view of the developing device according to the present invention, and Fig. 3 a and b are schematic diagrams showing the principle of the developing device of the present invention. . DESCRIPTION OF SYMBOLS 1... Photoreceptor, 10... Conductive developer, 11... Sleeve, 12... Tank, 13... Fixing plate.

Claims (1)

[Claims] 1. A sleeve having a large number of conductive acicular bristles on the surface by being partially immersed in a conductive developer filled in a tank is rotatably installed, and the sleeve surface is exposed above the surface of the developer. A developing device characterized in that the tips of the conductive needle-like bristles face the photoreceptor of the developing device without coming into contact with it, and a bias voltage is applied to the sleeve.