JPS6313068A - Electric field curtain developing device - Google Patents

Abstract

PURPOSE:To obtain an image of high picture quality stably for a long period by forming electrodes for an electric field curtain so that its cross section is in a flat plate shape at a development part facing a latent image carrier and intermediately high at conveyance parts before and behind it. CONSTITUTION:For example, when a 3-phase AC voltage is applied to electrode groups 4, 4a, and 4b, a moving electric field is produced and the toner at the reservoir part at the lower part of a container 2 is conveyed in a direction alpha. A drum 6 serves as a counter electrode to the electrodes 4 at the development part and while the toner is in reciprocal motion between the drum and electrode group 4, development is performed and the toner is consumed, so the toner is conveyed smoothly without being deposited on the electrodes 4. The electrodes 4 are flat plates, so neither edge effect nor white absence at a solid part is caused. The toner passed through the development part is conveyed to the upper part by a conveyance electrode 4b to falls from the upper end of a panel and is recovered in the container 2 and reused. The top surfaces of conveyance electrodes 4a and 4b are intermediately high, so not toner is conveyed smoothly without being deposited on the top surfaces of the electrodes, so that an image of high picture quality is obtained stably for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention [Field of Industrial Application] The present invention relates to a developing device that develops an electrostatic latent image or a magnetic latent image by applying an electric field curtain.

[Conventional technology]

A developing device that applied an electric field curtain was already developed in
This device is known from Japanese Patent No. 47811, but since it does not have a developing counter electrode, it has drawbacks such as an excessively strong narrowing φ edge effect.

In addition, in recent years, Japanese Patent Application Publication No. 58-2201580 and Japanese Patent Application Publication No. 59-1
A developing device of the type in which an electric field curtain is directly opposed to an electrostatic latent image has been proposed in Japanese Patent Application Laid-Open No. 78755-181371.

However, in these devices, the toner is not deposited on the electrode because it is subjected to strong force between it and the latent image bearing drum in the developing section, but the toner is not deposited on the electrode because it is not subjected to such force in the conveying section before and after the developing section. The drawback was that toner was deposited on top.

In order to solve this problem, Japanese Patent Application Laid-Open No. 59-189387
As described in Japanese Publication No. 58-189388, a developing device has been proposed in which the electrode is shaped so that the center portion is higher than the end portions.

[Problem that the invention seeks to solve]

However, when developing, since the tip of the electrode facing the image carrier drum in the developing section has a protruding structure, a parallel electric field is not formed between the developing electrode and the drum. If the speed is increased, electrode streaks may appear in the image in the direction of image movement, resulting in an extremely poor quality image.

The present invention eliminates all the drawbacks of the above-mentioned conventional example, and at the same time,
An object of the present invention is to provide an electric field curtain developing device that can stably obtain high-quality images over a long period of time.

Summary: Structure of the Invention [Means for Solving the Problems] The present invention provides an electric field curtain developing device that develops an electrostatic latent image or a magnetic latent image by conveying a developer using an alternating current electric field. This electric field curtain developing device is characterized in that the developing section facing the latent image carrier has a flat cross-sectional shape, and the conveying sections before and after the developing section have a mid-height cross-sectional shape.

[For production]

In the toner conveying sections before and after the developing section, since the electrodes of the electric field curtain have a medium height in cross section, toner does not adhere and accumulate thereon.

〔Example〕

FIG. 1 shows an example specifically illustrating the present invention.

1 is a toner, 2 is a toner storage container, 3 is a dielectric electric field curtain panel, 4 is an electrostatic or magnetic latent image carrier drum 6
electrodes arranged in parallel on the panel facing the developing section of 4;
Reference characters a and 4b are toner transport electrodes arranged in parallel on the panel before and after the electrode 4 arrangement portion. The electrode 4 of the developing section has a flat surface (the surface facing the drum 6), and its width and electrode interval are, for example, 0.1 to 0.5 am. Further, the width and spacing of the transport electrodes 4aφ4b are the same as those of the electrodes 4, but the height is medium as shown in the figure. 5 is an n-phase AC power source for driving the electric field curtain, 7 is an electrostatic latent image, and 8 is a developed image.

In the illustrated example, the electric field curtain for development is arranged diagonally, with a part of it facing the latent image carrier drum 6, and the developer particles are transported between the electrodes 4, 4a, and 4b in the direction of the arrow α in the figure.
are wired to each phase of the three-phase AC drive power supply 5, for example.

Since this embodiment uses negatively charged toner, a positive latent image is formed on the drum. If, for example, a three-phase AC voltage is applied to the electrode groups 4, 4a, and 4b, a moving electric field is generated, and the toner in the lower part of the container 2 is moved by α
In the developing section, the drum 6 becomes the opposite electrode of the electrode 4, and while the toner moves back and forth between the drum and the electrode group 4, development is performed and the toner is consumed, so that the toner does not accumulate on the electrode 4. , transported smoothly. Furthermore, since the electrode 4 is made of a flat plate, problems such as edge effects and white spots in solid areas do not occur.

The toner that has passed through the developing section is transported to the upper part by the transport electrode 4b, falls from the upper end of the panel, is collected in the container 2, and is reused. The above-mentioned transport electrodes 4a and 4b have the same width and the same spacing as the electrodes 4 of the developing section, but since the upper surfaces are formed with a medium height, the toner is transported smoothly without accumulating on the upper surfaces of the electrodes. The medium and high shapes of the transport electrodes 4a and 4b are as follows:
Electrodes 4, 4a, which may be circular or trapezoidal instead of the triangle shown in the figure.
The width φ interval of 4b, the mid-height shape of 4a and 4b, etc. are determined by the fluidity of the toner, the inclination of the electric field curtain panel, the applied voltage, etc.

C. As described in detail of the invention, the cross-sectional shape of the electrode of the electric field curtain is
In the developing section, since the flat plate faces the latent image bearing drum, the developing action is carried out smoothly, and high-quality images are obtained without edge effects or white spots in solid areas. Since the electrode cross sections of the conveyance sections before and after the electrodes are medium-height, stable conveyance is performed without toner being deposited thereon.

[Brief explanation of drawings]

The figure is a longitudinal sectional view showing an embodiment of the present invention. Reference numeral 1 denotes a developer, 2 a toner storage container, 3 an electric field curtain panel, 4 an electrode group of a developing section, 4a and 4b a transport section electrode group, 5 a power supply, and 6 a latent image carrier drum.

Claims (1)

[Claims] (1) In an electric field curtain developing device that conveys developer using an alternating current electric field to develop an electrostatic latent image or a magnetic latent image, the cross-sectional shape of the electrode of the electric field curtain is changed to a flat plate in the developing section facing the latent image carrier. , an electric field curtain developing device characterized in that the conveyance sections before and after the curtain are formed to have a middle height.