JPH0664360B2 - Toner for electrostatic image development - Google Patents

Description

The present invention relates to a novel negatively charged negative toner for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing and the like.

Originally, an electrostatic latent image can be developed and visualized by adhering toner by its electrostatic attraction, and as a developer for this electrostatic latent image, other powder developer than liquid developer is used. Is widely used.

This powder developer is made of natural resin or synthetic resin, coloring agent,
A two-component developer consisting of a mixture of a toner having an average particle size of 15 μm in which a charge control agent, a fluidizing agent, etc. are dispersed, and a carrier of 100 to 200 μm of iron powder or ferrite powder, and a natural resin or a synthetic resin. It can be roughly classified into a one-component type developer composed of an agent, a charge control agent, a fluidizing agent, and a magnetic material.

The two-component type developer achieves development by attaching toner charged by friction with a carrier to an electrostatic latent image. As a one-component type developer, conventionally, instead of a carrier, A toner charged by friction with a brush-shaped or plate-shaped friction member having the same function as this is known, and recently, a magnetic substance fine powder is kept in a dispersed state to obtain the magnetic substance. The toner, which is charged by mutual friction with the fine powder, is released. Thus, these developing toners are held positively or negatively charged depending on the polarity of the electrostatic latent image to be developed.

In order to keep the toner charged, it has been proposed to utilize the triboelectric chargeability of the resin, which is the main component of the toner, but in this method the toner charge is small and the solid surface resistance value is large, The obtained image is easily fogged and becomes unclear. Therefore, in order to impart desired triboelectrification properties to the toner, dyes and pigments that impart an electric charge, and a charge control agent have been added, which are practically used in the technical field today. For example, there are nigrosine-based oil-soluble dyes shown in JP-B-41-2427 and the like for imparting a positive charge to the toner, and JP-B-45-26478 for imparting a negative charge. There are metal-containing complex salt dyes and the like as disclosed in the publications and the like.

However, these dyes and pigments as charge control agents have complicated structures and poor stability, and are decomposed or deteriorated by mechanical friction and changes in shock / temperature / humidity conditions, electric shock and light irradiation, for example. Therefore, the charge controllability is easily lost. Also, one essential deficiency is that it is a colored substance, which violates the requirement that a charge control agent that can be regarded as colorless or substantially colorless is required for toner having a specific hue. .

Recently, as a material satisfying this requirement, JP-A-53-127726, JP-A-57-104940, and JP-A-57-111541.
Various complex compounds are disclosed in JP-A No. 57-124357 and the like, but the complex compounds are still inevitable to some coloration.

The present inventors have a good dispersibility with a resin component, have thermal stability up to a temperature at which melt kneading can be sufficiently performed, and are colorless substances that can impart a negative charge to a toner. As a result of diligent research on the compound that can be formed, the inventors have found that the zinc compound of the dithiocarbamic acid derivative is particularly excellent, and completed the present invention.

The present invention is a negatively charged polar toner for developing an electrostatic charge image, which contains a zinc compound of a dithiocarbamic acid derivative as a negative charge control agent.

Examples of the zinc compound of the dithiocarbamic acid derivative according to the present invention include zinc dimethyldithiocarbamate (PZ),
Zinc diethyldiothicarbamate (EZ), Zinc di-n-butyldioticarbamate (BZ), Zinc N-methyl-N-phenyldithiocarbamate, Zinc N-ethyl-N-phenyldithiocarbamate ( PX), zinc dibenzyldithiocarbamate (ZTC) and the like.

By the way, the amount of the zinc compound of the dithiocarbamic acid derivative added to the toner component is 100 parts by weight of the resin,
Generally, it is contained in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight.

In addition to the zinc compound of the dithiocarbamic acid derivative, the toner of the present invention has a styrene resin, a styrene-acrylic resin, a styrene-butadiene resin, an epoxy resin in consideration of adhesiveness, storability, fluidity, pulverizability and the like. 1 of well-known toner resins such as resin, polyester resin, paraffin wax, etc.
It is used as a mixture of two or more species. As the colorant, many known dyes and pigments can be used,
Particularly excellent color copying toners include benzidine yellow, quinacridone, copper phthalocyanine blue, and copper phthalocyanine green.

The toner of the present invention usually provides a two-component developer when mixed with a carrier, but it can of course also be used as a one-component developer.

Hereinafter, specific examples of the present invention will be described with reference to Examples. In the examples, "part by weight" is abbreviated as "part".

Example 1 Epoxy resin: 100 parts (Ciel Chemical Co., Epicoat 1004) Carbon black: 6 parts (Mitsubishi Chemical Co., MA-100) Nox Cellar PZ: 2 parts ( Trade name, manufactured by Ouchi Shinko Kagaku Co., Ltd .; Zinc dimethyldithiocarbamate) Premixes are prepared by uniformly premixing the above-mentioned compounds in a ball mill. Then, the mixture was melt-kneaded with a hot roll, cooled, coarsely pulverized with a vibration mill, and further finely pulverized with an air jet mill. The fine powder obtained is classified to a particle size of 10 to 20.
A black toner with μm was obtained.

To 3 parts of the obtained toner, 97 parts of iron powder carrier (TEFV 200/300 made by Nippon Iron Powder) was mixed to prepare a developer. The initial blow-off charge of this developer is -20.5 μC / g.
It was. When a toner image was formed on a commercially available selenium drum by using this developer by a magnetic brush development method, a clear black fine line-free image having no fog was obtained. With this toner, the copy quality was not deteriorated even after 50,000 sheets were continuously copied.

Example 2 Styrene-n-butyl methacrylate copolymer resin (65/3
5) ・ ・ ・ ・ ・ 100 parts CISolvent Yellow77 ・ ・ ・ ・ ・ 6 parts Nox Cellar EZ ・ ・ ・ ・ ・ 2 parts (trade name, manufactured by Ouchi Shinko Kagaku Co .; zinc dimethyldithiocarbamate) The above composition was used in Example 1 A yellow toner was prepared in the same manner as described above.

97 parts of iron powder carrier was mixed with 3 parts of the obtained toner to prepare a developer. The initial blow-off charge amount of this developer was -19.6 μC / g. When this developer was copied in the same manner as in Example 1, a clear yellow image without fog was obtained. With this toner, the copy quality was not deteriorated even after 50,000 sheets were continuously copied.

Example 3 Styrene-n-butyl methacrylate copolymer resin (65/3
5) ・ ・ ・ 100 parts Red dye ・ ・ ・ ・ ・ 8 parts (Variant Pink2310 manufactured by Orient Chemical Industry Co., Ltd.) NOXCELLER EZ ・ ・ ・ ・ ・ 2 parts (trade name, manufactured by Ouchi Shinko Chemical Co., Ltd .; Jail) Zinc dithiocarbamate) A red toner was prepared by treating the above-mentioned composition in the same manner as in Example 1.

A developer was prepared by mixing 97 parts of an iron powder carrier with 3 parts of the obtained toner. The initial blow-off charge amount of this developer was -17.3 μC / g. When this developer was copied in the same manner as in Example 1, a clear red image without fog was obtained. With this toner, the copy quality was not deteriorated even after 50,000 sheets were continuously copied.

Example 4 Styrene-n-butyl methacrylate copolymer resin (65/3
5) ・ ・ ・ ・ ・ 100 parts Blue dye ・ ・ ・ ・ ・ 8 parts (Valifast Blue 2606, manufactured by Orient Chemical Industry Co., Ltd.) Blue pigment ・ ・ ・ 3 parts (Phthalocyanine pigment) Nocceller PX ・ ・ ・ ・ ・ 2 Parts (trade name, manufactured by Ouchi Shinko Chemical Co., Ltd .; N-ethyl-N-phenyldithiocarbamate zinc) The above formulation was treated in the same manner as in Example 1 to prepare blue toner.

97 parts of iron powder carrier was mixed with 3 parts of the obtained toner to prepare a developer. The initial blow-off charge amount of this developer was −21.3 μC / g. When this developer was copied in the same manner as in Example 1, a clear blue development without fog and good fine line reproducibility was obtained. This toner is a continuous copy
No deterioration in copy quality was observed even after 50,000 sheets.

Comparative Example 1 A black toner was obtained in the same manner as in Example 1 except that the noxcellor PZ (zinc dimethyldithiocarbamate) of Example 1 was replaced with chromium dimethyldithiocarbamate, and an iron powder carrier ( A developer was prepared by mixing 97 parts of Nippon Iron Powder Co., Ltd., trade name: TEFV 200/300).

The initial blow-off charge amount of the developer was +10.3 μC / g and did not show negative chargeability.

Comparative Example 2 A yellow toner was obtained in the same manner as in Example 4 except that the noxcellor EZ (zinc diethyldithiocarbamate) of Example 2 was replaced with cobalt diethyldithiocarbamate, and an iron powder carrier ( A developer was prepared by mixing 97 parts of Nippon Iron Powder, trade name: TEFV 200/300).

The initial blow-off charge amount of the developer was +13.6 μC / g, and it did not exhibit negative chargeability.

Claims (2)

[Claims] 1. A negatively chargeable toner for developing an electrostatic image, comprising a zinc compound of a dithiocarbamic acid derivative as a negative charge control agent. 2. The negatively chargeable toner for developing an electrostatic image according to claim 1, wherein the zinc compound of the dithiocarbamic acid derivative is 0.5 to 5 parts by weight with respect to 100 parts by weight of the resin.