JPH01204068A - Dry process developer - Google Patents

Abstract

PURPOSE:To obtain a dry process developer which has good flowability and cleanability, is excellent in environmental stability and durability and obviates generation of toner filming on the surface of a carrier by external adding fine particles of cerium fluoride to a toner. CONSTITUTION:The fine particles of the cerium fluoride are stuck to the particle surfaces of the toner consisting of a binder resin and coloring agent. The sticking may be mechanical sticking and may be loose fixing on the surfaces. The fine particles of the cerium fluoride are not required to coat the entire surface of the toner particles. In addition, the fine powder may be coated partially as the aggregate but the coating in a single-layer particle state is more preferable. Styrene, ethylene, etc., are used as the binder resin of the toner and, for example, carbon black, aniline blue, etc., are used as the coloring agent. The high flowability is obtd. with this dry process developer. In addition, the developer has the good flowability and cleanability, is excellent in the environmental stability and durability and does not generate the toner filming on the carrier surface.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a dry developer for developing electrostatic latent images used in electrophotography and electrostatic recording.

Conventional technology Dry developers can be roughly divided into one-component developers, which use the toner itself with coloring material dispersed in a binder resin, and two-component developers, which use the toner mixed with a carrier. After the electrostatic latent image formed on the photoreceptor is developed with these developers and the toner on the photoreceptor is transferred, the toner remaining on the photoreceptor is cleaned. Therefore, the dry developer is used in the copying process. In particular, it is necessary to satisfy various conditions in the developing process or the cleaning process. In other words, the toner is not produced as an aggregate during development;
Particles are subjected to development on both sides, and for this purpose, it is necessary that the toner has sufficient fluidity and that the fluidity or electrical properties do not change over time or with the environment (temperature, humidity). Furthermore, in the case of a two-component developer, it is necessary to prevent a phenomenon in which toner sticks to the carrier surface (so-called toner filming). Further, during cleaning, it is necessary that residual toner is easily removed from the surface of the photoreceptor, and that the photoreceptor is not damaged when used with a cleaning member such as a blade or wear. In order to meet these various requirements, in dry developers, one-component developers or two-component developers are used that externally add inorganic fine powder such as silica, organic fine powder such as fatty acids and their derivatives, metal salts, fluorine resin fine powder, etc. to the toner. Various methods have been proposed, and attempts have been made to improve fluidity, durability, and cleanability.

Problems to be Solved by the Invention However, among the additives proposed so far, inorganic oxides such as silica, titania, and alumina significantly improve fluidity, but the surface layer is dented and scratched by hard inorganic fine powder. It is easy to use, and toner tends to stick to damaged areas. Furthermore, even if toner does not stick, poor cleaning tends to occur over time, leading to image deterioration, and it is considered to be extremely difficult to achieve both of the above-mentioned characteristics of powder fluidity and cleanability. Other additives also have advantages and disadvantages in meeting the above requirements, and do not satisfy all requirements.

The present invention was made under these circumstances.

The purpose of the present invention is to provide a toner that has good fluidity and cleanability, excellent environmental stability and durability, and does not cause toner filming on the surface of a photosensitive plate or a carrier used in a two-component development system. Our mission is to provide excellent dry developers.

Means and Action for Solving the Problems The above objects of the present invention are achieved by externally adding cerium fluoride fine particles to the toner. That is, the dry developer of the present invention is characterized in that cerium fluoride fine particles are externally added to the toner.

The dry developer according to the present invention has cerium fluoride fine particles adhered to the surface of toner particles made of a binder resin and a colorant, and this adhesion may be simply mechanical adhesion, or the surface It may be loosely attached to the Further, the cerium fluoride fine particles do not need to cover the entire surface of the toner particles. Further, although part of the fine powder may be coated as an aggregate, it is preferable that the fine powder is coated in the form of a single layer particle.

This is because the low energy surface properties of cerium fluoride itself are utilized rather than preventing direct contact between toners as powdery inclusions between individual toner particles.

Furthermore, the cerium fluoride fine particles also have a lubricant effect, forming a lubricating film on the surface of the photoreceptor, while also making it difficult to cause white spots or fogging in terms of image quality.

The present invention will be explained in detail below.

The cerium fluoride fine particles externally added to the toner of the present invention have a particle size of 0.01 μm to 30 I1 m, preferably 0.01 μm to 10 ttm.

On the other hand, toner is mainly composed of a binder resin and a colorant.

Binder resins used include styrenes such as styrene and chlorostyrene; ethylene, propylene, butylene,
Monoolefins such as isobutylene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate; methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methacrylic acid Esters of α-methylene aliphatic monocarboxylic acids such as methyl, ethyl methacrylate, butyl methacrylate, and dodecyl methacrylate; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl butyl ether; vinyl methyl ketone, vinyl hexyl ketone, and vinyl ether; Homopolymers or copolymers of vinyl ketones such as propenyl ketone can be exemplified, and representative binder resins include polystyrene, styrene-acrylic alkyl copolymers, and styrene-methacrylic copolymers. Examples include acid alkyl copolymers, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, styrene-maleic anhydride copolymers, polyethylene, and polypropylene. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin, and waxes.

In addition, as coloring agents, carbon black, aniline blue, calcoyl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow,
Representative examples include methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, and rose bengal.

The binder resin and colorant are not limited to those exemplified above, and any known ones such as a charge control agent can be used as necessary.

Further, the toner in the present invention may be a magnetic toner containing a magnetic material or a capsule toner.

In the present invention, a toner having an average particle size of about 3 CHtm or less, preferably 3 to 20 CHtm can be used.

As a method for producing the dry developer of the present invention, toner and cerium fluoride fine particles are mixed using a blender and uniformly dispersed. In addition, when the dry toner of the present invention is used as a two-component developer by combining it with a carrier, first the toner and cerium fluoride fine particles are uniformly dispersed and mixed using a blender, and then this mixture and the carrier are mixed. Alternatively, the toner, carrier, and cerium fluoride fine particles may be blended simultaneously.

Moreover, at this time, various additives may be added as necessary. These additives include various things such as charge control agents, cleaning aids, and fluidity promoters. As this bimonthly blender, a V-blender, Henschel blender, etc. can be used.

In the present invention, the cerium fluoride content contained in the dry developer is o, based on the total weight of toner in the developer.
It is desirable that the amount is about oi to 10% by weight.

The dry developer of the present invention may be used as a two-component developer by mixing with iron powder, glass beads, ferrite powder, nickel powder, or carrier particles whose surfaces are coated with a resin, if necessary. The dry type developer of the present invention can be used as appropriate depending on the dry process used, but - Numerically speaking, it can be used for electrostatic latent image carriers such as electrophotography and electrostatic recording. Used in the process of forming a latent image, making it visible using a developer in a developing machine, transferring the visible image to another carrier, and then cleaning the toner remaining on the electrostatic latent image carrier. be able to. As the electrostatic latent image carrier, all conventionally known ones can be used, such as Se-based photoreceptors, organic photoreceptors, amorphous silicon photoreceptors, etc., or those whose surfaces are overcoated as necessary. It is. Further, as the developing machine, any known one such as a conventional two-component developing machine or a -component developing machine can be used.

The dry developer according to the present invention can obtain high fluidity, and is particularly suitable for the thin layer development method, in which a thin layer of toner is formed on a developing roll, or the high-speed development method, in which a latent image moving at high speed is developed. The effect of the developer of the present invention becomes remarkable when this method is used. As a cleaning means, all known methods such as cleaning by blade pressure bonding, web fur brush cleaning, etc. can be used, but the dry developer of the present invention can obtain particularly high improvement effects especially in the residual toner cleaning method by blade pressure bonding. can. T + 02, S to improve powder flowability! 02.
Other external additives such as 5n02 and A1203 may also be added.

EXAMPLES The present invention will be explained below with reference to Examples and Comparative Examples, but the present invention is of course not limited to these Examples. In addition, "parts" in the following examples means "parts by weight."

Example 1 Styrene-butyl acrylate 100 parts copolymer (80/20) Carbon black 10 parts (Regal 330, manufactured by Cabot Corporation) Low molecular weight polypropylene 5 parts (Viscol 660P, manufactured by Sanyo Chemical Co., Ltd.) Charge control agent
1 part (Bontron 03, manufactured by Orient Chemical Co., Ltd.) The above ingredients were melt-kneaded in a Banbury mixer, cooled and pulverized in a jet mill, and the finely pulverized product was further classified in a separator to obtain an average particle size of 11 μm. Got toner. To 100 parts of this toner, 1 part of silica fine particles with an average particle size of 0.1 μm and 0.5 parts of cerium fluoride fine particles (manufactured by Santoku Metals ■) with an average particle size of 0.8 #l were dispersed and mixed using a blender. Ta. After dispersion and mixing, the average particle size is 90uIn
was mixed with iron powder at a weight ratio of 3=97 to obtain a two-component developer.

Example 2 For 100 parts of toner with an average particle size of 11 μm obtained after kneading, crushing, and classification with the same composition as in Example 1, an average particle size of 0.8
1.0 part of μm cerium fluoride fine particles (manufactured by Gotoku Metal ■) were dispersed and mixed using a blender. After dispersion and mixing, the same operation as in Example 1 was carried out to obtain 1 q of two-component developer.

Example 3 1 part of titanium oxide fine particles with an average particle size of 0.1/ffl was added to 100 parts of toner with an average particle size of 111M obtained by kneading, pulverizing, and classifying the same composition as in Example 1, and 0.5 parts of cerium fluoride fine particles (manufactured by Gotoku Metal ■) having an average particle diameter of 0.8 μs were dispersed and mixed using a blender.

After dispersion mixing, fluororesin coated ferrite carrier,
They were mixed at an average particle size of 90 μs and a weight ratio of 3=97 to obtain a two-component developer.

□ Comparative Example 1 A two-component developer was obtained in the same manner as in Example 1 except that the cerium fluoride fine particles were removed.

Comparative Example 2 A two-component developer was obtained in the same manner as in Example 3 except that the cerium fluoride fine particles were removed.

Comparative Example 3 Same composition and same method as Example 1, average particle size 11μ
m toner was obtained. This toner was mixed with iron powder having an average particle size of 90 μR at a weight ratio of 3:97 without performing any additive treatment to obtain a two-component developer.

Using the dry developers of Examples 1 to 3 and Comparative Examples 1 to 3 above, a continuous copying test was conducted using an electrophotographic copying machine (1065 copying machine manufactured by Xerox Corporation in the United States), and the following results were obtained. It was done.

Table 1: Effects of the Invention The dry developer of the present invention is characterized by externally adding cerium fluoride fine particles to the toner, and as a result, the dry developer has good fluidity and cleanability, and is environmentally stable. It has excellent durability and does not cause the toner filming phenomenon on the photosensitive plate or the toner filming phenomenon on the surface of the carrier used in the two-component development method.

Such effects of the dry developer of the present invention are particularly noticeable in the thin layer development method in which a thin layer of toner is formed on a developing roll, or in the high speed development method in which a latent image moving at high speed is developed. Demonstrated.

Patent applicant Fuji Hillox Co., Ltd. Agent
Patent attorney Tsuyoshi Seibe

Claims (1)

[Claims] (1) A dry type developer characterized in that it is formed by externally adding cerium fluoride fine particles to dry type toner particles.