JPH07104623B2 - Developer composition for electrostatic image - Google Patents

Description

TECHNICAL FIELD The present invention relates to a developer used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing and the like. More specifically, the present invention relates to a developer composition containing a positively charged toner for a dry developer or a carrier for a dry developer.

2. Description of the Related Art In electrophotography, a photoconductive substance such as selenium is used as a photoconductor, an electric latent image is formed by various means, and a magnetic brush developing method is used for the latent image. A method in which toner is made to adhere and visualized is generally adopted.

In the developing step, carrier particles called a carrier are used to give an appropriate amount of positive or negative electric charge to the toner, and a method of obtaining an electric charge by friction, recently, a magnetic fine powder is added to the toner, A frictional charging method using a brush-shaped or plate-shaped frictional member having a charging ability or a charging ability by mutual friction between them is known. The developer toner used therein must carry a positive or negative charge depending on the polarity of the electrostatic latent image being developed.
A conventional developer toner is obtained by melt-kneading a thermoplastic resin with a pigment such as carbon black, then pulverizing and classifying the toner to obtain a developing toner, and utilizing the triboelectric charging property of the resin as the main component of the toner, It was an attempt to satisfy the conditions. However, since the developing toner obtained by this method has a low charging property, it has a problem in image characteristics such as fogging and a short life. Therefore, in order to solve these problems, a charge control agent is added to the toner to impart chargeability.

Problems to be Solved by the Invention Among the recently proposed ones, examples of the charge control agent for imparting a positive charge include a nigrosine dye and the like.
It is usually difficult to uniformly melt and disperse the dyes of this type in the binder resin, so that the charge amount varies among the obtained toner particles, and the charge amount distribution becomes extremely wide, and the stability is stable. It has the disadvantage of being poor.

Therefore, it is an object of the present invention to provide a developer composition for electrostatic images in which the above-mentioned drawbacks are improved.

Means and Actions for Solving Problems The above object of the present invention is to provide the following general formula: (In the formula, R ₁ and R ₂ are the same or different groups and each represent a hydrogen atom or a substituted or unsubstituted alkyl group.) In the developer composition, a metal complex of 4-pyrone It can be achieved by containing

Hereinafter, the present invention will be described in detail.

In the present invention, examples of the metal complex of 4-pyrone represented by the above general formula used as the charge control agent include the following.

Cobalt complex of 2-methyl-3-hydroxy-4-pyrone Cobalt complex of 2-methyl-5-hydroxy-4-pyrone These metal complexes of 4-pyrones can be synthesized by a known method. For example, taking the case of a cobalt complex of 2-methyl-3-hydroxy-4-pyrone (maltol) as an example, it is synthesized as follows.

Maltitol is dissolved in a solvent such as methanol or ethanol, or suspended in water or aqueous alcohol, and then an inorganic acid salt such as cobalt chloride or cobalt sulfate, an organic acid salt such as cobalt acetate, or a complex salt such as cobalt acetylacetonate. The aqueous solution has a molar ratio of maltol and cobalt of 1: 1.
To 4: 1 and adjust the pH of the mixture with aqueous alkaline solution. Although it reacts with maltol even at room temperature, it may be heated so that maltol and the complex are not decomposed depending on the case. The method of obtaining the product depends on the nature of the complex. When the solubility in the reaction solvent is low, the precipitated complex is filtered as it is, or slightly concentrated and filtered. If the solubility in the reaction solvent is high, once concentrated to dryness, solid-liquid extraction is performed with a solvent that selectively dissolves the complex, and the extract is concentrated to dryness or washed with a solvent that dissolves components other than the complex. To remove impurities and obtain the desired product.

Similarly, instead of the above cobalt complex, Fe, Ni, Cr, M
Metal complexes of n, Sn, Pb, etc. can be synthesized.

In the present invention, the metal complex of 4-pyrone is used as a charge control agent, but may be contained anywhere in the developer composition as long as it can exhibit a positive charging ability. or,
It can be used as either a one-component developer or a two-component developer.

When it is used as a one-component developer, it may be added or dispersed in the binder resin of the toner, or may be attached to the surface of the toner particles.

When used as a two-component developer, it may be used as either toner particles or carrier particles.

When the metal complex of the 4-pyrone is used, it is usually used by dispersing it in a binder resin, but it is not necessarily limited thereto.
A metal complex of pyrone may be added and mixed to control the charge on the toner surface. When it is added to the binder resin of the toner, it is preferable because it can be uniformly dispersed in the toner and a developer having no variation in the charge amount between the toner particles can be obtained. or.
Other additive components may be surface-coated with the metal complex of the 4-pyrone in advance and used. When it is used as a carrier, it can be contained in a carrier coating agent or a carrier binder to control the charging of the toner.

The content ratio of the metal complex of the 4-pyrone is not particularly limited. For example, when it is contained in the toner, the content of the metal complex is 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. It is preferable to add it.

Examples of the binder resin used for the toner in the developer composition of the present invention include styrenes such as styrene, chlorostyrene and vinyl styrene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate;
Α such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate
-Ester of methylene aliphatic monocarboxylic acid; vinyl ether such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether; homopolymer or copolymer of vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone, etc. As a typical binder resin, polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene can be used. Mention may be made of maleic anhydride copolymers, polyethylene, polypropylene, polyesters, polyurethanes, epoxy resins.

Further, as the colorant of the toner, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, deupon oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, etc. Can be illustrated as a typical one.

The binder resin and the colorant are not limited to those exemplified above, and any known one can be used.

Further, the present invention can be applied to a magnetic toner containing a magnetic material and a capsule toner.

As this toner, one having an average particle diameter of about 30 μm or less, preferably 3 to 20 μm can be used.

In the case where the developer composition of the present invention is a two-component developer, any known carrier can be used as the carrier. For example, iron powder, a resin-coated carrier, a carrier in which magnetic powder is dispersed in resin, and the like can be used.

If desired, various additives may be added to the developer composition of the present invention. Examples of these additives include various substances such as charge control agents, cleaning aids, fluidity promoters, and the like.

The developer composition of the present invention is used for developing an electrostatic latent image formed on a photoconductor or an electrostatic recording material. That is,
An electrostatic latent image is formed electrophotographically on a photoreceptor made of an inorganic photoconductive material such as selenium, zinc oxide, cadmium sulfide, or amorphous silicon, or an organic photoconductive material such as a phthalocyanine pigment or a bisazo pigment, or polyethylene terephthalate. An electrostatic latent image is formed on an electrostatic recording body having a dielectric substance such as a needle-shaped electrode by a magnetic brush method, a cascade method,
By a developing method such as a touch-down method, the developer of the present invention is attached to the electrostatic latent image to form a toner image. This toner image is transferred to a transfer material such as paper and then fixed to form a copy, and the toner remaining on the surface of the photoconductor or the like is cleaned. As the cleaning method, various methods such as a blade method, a brush method, a web method and a roll method can be used.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is in no way limited by these examples.

Example 1 A cobalt complex of maltol was prepared by the following method.

22.8 g of maltitol was dissolved in 2 l of methanol, and a solution of 12.0 g of cobalt chloride hexahydrate in 750 ml of water was added thereto. A caustic soda aqueous solution was added to adjust the pH to 10, the mixture was stirred at room temperature for 1 hour, and then concentrated to dryness under reduced pressure. 500 ml of ethanol was added to the obtained solid and the mixture was stirred for 30 minutes and then filtered, and the separated crystals were dried under reduced pressure at 40 ° C. overnight to form a cobalt complex of maltol (hereinafter abbreviated as Co-1). 23.7
got g. The infrared absorption spectrum of Co-1 is shown in FIG.

Styrene-butyl acrylate copolymer (80/20) 100 parts Carbon black (Regal 330) (manufactured by Cabot) 1
0 parts Low molecular weight polypropylene (Viscor 660P) (manufactured by Sanyo Kasei Co., Ltd.) 5 parts Co-1 1 part The above components are melt-kneaded with a Banbury mixer, cooled, and then finely pulverized with a jet mill. To obtain a toner having an average particle size of 11 μm.
On the other hand, the carrier was obtained by melt-kneading the styrene-acrylic copolymer and the magnetic powder, pulverizing and classifying.

90 parts of this carrier was mixed with 10 parts of the toner to prepare a developer composition.

Example 2 A lead complex of maltol was prepared by the following method.

40.1 g of maltitol was dissolved in 3.5 l of methanol, and a solution of 27.8 g of lead chloride in 1.3 l of water was added thereto. A caustic soda aqueous solution was added to adjust the pH to 10, the mixture was stirred at room temperature for 1 hour, and then concentrated under reduced pressure to precipitate crystals. The concentrated solution was filtered, and the crystals separated by filtration were dried under reduced pressure at 40 ° C. overnight to obtain 42.4 g of a maltyl lead complex (hereinafter abbreviated as Pb-1). The infrared absorption spectrum of Pb-1 is shown in FIG.

Styrene-butyl acrylate copolymer (80/20) 100 parts Carbon black (Regal 330) (manufactured by Cabot) 1
0 part Low molecular weight polypropylene (Viscor 660P) (manufactured by Sanyo Kasei Co., Ltd.) 5 parts Pb-1 1 part The above components were treated in the same manner as in Example 1 to obtain a developer composition.

Example 3 In the same manner as in Example 1, 23.5 g of a cobalt complex of 2-methyl-5-hydroxy-4-pyrone (alomaltol) (hereinafter abbreviated as Co-2) was obtained. The infrared absorption spectrum of Co-2 is shown in FIG.

Styrene-butyl acrylate copolymer (80/20) 100 parts Carbon black (Regal 330) (manufactured by Cabot) 1
0 part Low molecular weight polypropylene (Viscole 660P) (manufactured by Sanyo Kasei Co., Ltd.) 5 parts Co-2 1 part The above components were treated in the same manner as in Example 1 to obtain a developer composition.

Comparative Example Styrene-butyl acrylate copolymer (80/20) 100 parts Carbon black (Regal 330) (manufactured by Cabot) 1
0 part Low molecular weight polypropylene (Viscol 660P) (manufactured by Sanyo Kasei Co., Ltd.) 5 parts Nigrosine dye (Bontron N-03) (manufactured by Orient Chemical Co.) 1 part The above components are treated in the same manner as in Example 1 to prepare a developer composition. I got a thing.

A continuous copying test was carried out with a copying machine FX-7770 (manufactured by Fuji Xerox Co., Ltd.) using these developer compositions,
The following results were obtained.

Effect of the Invention Since the developer composition of the present invention contains the metal complex of the 4-pyrone, the rate of charge increase is fast, the triboelectric charge amount does not vary among the toner particles, and the toner composition is very stable and positive. Shows no charging property and does not cause fog early generation or in-machine contamination during running. In addition, the charging control function does not deteriorate due to environmental changes such as temperature and humidity,
It exhibits stable development characteristics.

[Brief description of drawings]

1 to 3 show Embodiments 1 to 3 of the present invention, respectively.
It is an infrared absorption spectrum figure of the compound used by.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayoshi Aoki 1600 Takematsu, Minamiashigara City, Kanagawa Fuji Xerox Co., Ltd. Takematsu Plant (72) Inventor Kenji Nakaoka 1 Toray, 9 Oe-cho, Minato-ku, Aichi Prefecture Nagoya Inside the Nagoya Plant (72) Inventor Yoshihisa Matsukuma 1-9 Oemachi, Minato-ku, Aichi Prefecture Nagoya City Toray Ltd. Nagoya Plant

Claims (1)

[Claims] 1. A developer composition for an electrostatic image comprising a metal complex of 4-pyrone represented by the following general formula as a charge control agent. (In the formula, R ₁ and R ₂ are the same or different groups and represent a hydrogen atom or a substituted or unsubstituted alkyl group.)