JPH0366664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a one-component phenomenon agent used in electrostatic recording. More specifically, the present invention relates to a one-component phenomenon agent used in electrostatic recording. This invention relates to a developing agent used in a device in which the developing agent is cleaned with a blade after viewing directly on the dielectric or projecting an image onto a screen, so that the dielectric and the developing agent can be used repeatedly.

The present invention provides a phenomenon agent that is perfectly spherical in shape and can be used repeatedly.

A conventional one-component phenomenon agent of this type is one in which a thermoplastic resin and magnetite are kneaded with a roll, pulverized, and then sprinkled with carbon to lower the resistance. The phenomenon agent obtained in this way has irregular shapes and has corners. When this agent is used for cleaning with a blade after the phenomenon, the angular parts of the phenomenon agent are crushed by the pressure applied between the blade and the dielectric, producing particles with small diameters. If these crushed particles with a small diameter are repeatedly used, there is a problem that fogging or filming occurs on the dielectric material, which adversely affects the image.

The present invention provides agents that overcome this problem.

That is, when the agent is repeatedly used, the agent must be strong enough to not be crushed by the pressure applied between the blade and the dielectric, and the shape should be free from sharp edges. In the present invention, in order to impart strength to the phenomenon agent, a thermosetting resin is used as a binder, and the particles are granulated into a true spherical shape.

FIGS. 1 and 2 show a truly spherical developing agent of the present invention. FIG. 1 shows a product obtained by uniformly dispersing and granulating a resin 1, a magnetic fine powder 2, and a conductive agent 3. Further, FIG. 2 shows a case in which resin and magnetic powder are uniformly dispersed and granulated, and then a conductive material is dispersed in resin 4 and coated on the particles described above.

The resin used here is a thermosetting resin such as melamine resin or epoxy resin. The magnetic fine powder includes iron compounds such as iron tetroxide and iron sesquioxide, or composites with other metals, or metals such as iron, nickel, cobalt, and manganese, or compounds thereof. Carbon is used as the conductive agent. As the conductive agent in FIG. 2, in addition to carbon, fine powder of a compound semiconductor having a low resistivity such as copper iodide CuI can be used. Conductivity can be improved by dispersing these fine powders in a resin and coating the particle surfaces.

The developing agent thus obtained has a specific resistance of granules of 10 ¹⁰ Ω·cm or less, and the specific resistance can be changed as appropriate depending on the application and the developing method.
In order to obtain a good image as a developing agent, a particle size of 5 to 30 .mu.m is appropriate from the viewpoint of fogging and resolution.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Water-soluble melamine resin (solid content 80%, Sumitomo Chemical Co., Ltd.)
M-3) 125g Magnetite (EPT-500 manufactured by Toda Kogyo Co., Ltd.) 50g Water 200g The above composition was ground and dispersed in a ball mill for about 30 minutes, and then mixed with 40g of carbon (Conductex SC manufactured by Nippon Columbian Carbon Co., Ltd.). A sample soaked in 300 g of water is added to the above composition, and 200 g of water is further added and pulverized and dispersed for 1 hour. 10 g of a curing agent (Sumitex Accelerator ACX, manufactured by Sumitomo Chemical Co., Ltd.) is added to the dispersion thus obtained and mixed. This dispersion was granulated using a spray drying device and
A spherical agent with a particle size distribution of 80 μm, good fluidity, and good conductivity was obtained. When this material was classified into particle sizes of about 5 to 30 μm and the electrostatic latent image obtained on the dielectric material was developed, a fog-free image was obtained. Furthermore, when cleaning with the same blade was repeated using the same agent, there was no possibility that the particle size would be broken and fogging would occur.

Example 2 Granulation was performed in the same manner as in Example 1 using fine iron powder (manufactured by Kanto Denka Kogyo Co., Ltd.) instead of magnetite, to obtain a truly spherical agent. Using this, the developing agent was repeatedly used in the same manner as in Example 1, and as a result, there was no crushed developing agent and no fogging was observed.

As described above, the phenomenon agent of the present invention can be used repeatedly without breaking under the pressure applied between the photoreceptor and the blade, causing fog, toner filming, or damage to the photoreceptor, and can produce good images. Obtainable.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are schematic diagrams showing an example of the structure of the phenomenon agent of the present invention. 1, 4... Resin, 2... Magnetic material, 3... Conductive agent.

Claims (1)

[Claims] 1. A phenomenon agent comprising a magnetic material, a resin, and a conductive agent, the resin being a thermosetting resin, and having a substantially perfect spherical shape.