JPH06230607A - Yellow color toner for electrostatic latent image development - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] A one-component system or two-component system that provides uniform image density, hardly causes peripheral effects and fog, is suitable for high-speed development, and has excellent durability and environmental stability Provided is a yellow toner for developing an electrostatic latent image in a component type developer. Further, this toner is a yellow color toner for electrostatic latent image development, which is not affected by changes in temperature and humidity, does not cause offset development, and has decomposition products excellent in safety and hygiene. A yellow color toner for developing an electrostatic latent image containing a colorant and a binder resin as main components, wherein the colorant is represented by the following formula (I) The compound represented by

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yellow color toner used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art As means for developing an electrostatic latent image formed on an electrophotographic photoreceptor or an electrostatic recording body, a liquid developer (wet developing method) in which toner is dispersed in a carrier liquid is used. A method in which a toner in which a coloring agent is dispersed in a coating resin or a one-component or two-component dry developer in which this toner is mixed with a solid carrier is used (dry development method) is generally adopted. And each of these has its strengths and weaknesses,
At present, a dry developing method, especially a two-component developer is widely used. Conventionally, a toner for a two-component developer is obtained by adding a colorant (dye, pigment) to a binder resin, melt-kneading the mixture with a two-roll mill, and then finely pulverizing it to a particle size of about 1 to 30 μm. The one used is used. Such toner is mixed with a carrier having a particle size of about 50 to 100 μm to form a two-component developer.

By the way, in order that the toner of the two-component type developer contributes to the development of the electrostatic latent image, the toner and the carrier cause a certain frictional charge in the copying machine and have a stable charge amount. Toner must supply the electrostatic latent image. Therefore, the binder resin and / or the colorant of the toner is appropriately selected so as to obtain a desired triboelectrification property, or the charge control agent (the charge characteristic of the toner is controlled with respect to the friction with the carrier). The substance is usually added to the toner.

However, in reality, the selection of the binder resin has not been progressed as expected.
For example, chlorinated paraffin, unsaturated polyester, etc. are used as a binder resin to control the toner to have a negative chargeability, or a specific polyester resin (non-linear low melting point aromatic having a kind of cross-linking structure from the beginning). It is known to use a resin such as a reaction product of a group resin and a salicylic acid chelate, but it is difficult to obtain a desired molecular weight as a binder with these resins, and therefore, important thermal properties (fixing property) as a toner are not obtained. However, there are disadvantages such that the melting characteristics of the heat roll cannot be obtained and a copy discharge error occurs when the copy is wound around the heat roller, and the toner image on the paper is transferred to the roller surface and the characters are unclear, which causes offset development.

Regarding the selection of the above-mentioned colorant, although it is an example of a toner for liquid developers, many kinds of dyes such as anthraquinone derivatives (long-chain alkylphenyl group, long-chain alkylamino group, etc. are introduced) And those which are made to be electrically charged, those obtained by reacting with a surfactant, those obtained by introducing an anthraquinone group into an acidic group-containing water-soluble dye, etc. have been proposed. However, the fact that addition of dyes typified by these anthraquinone derivatives rarely shows good effects in the production of dry toners, especially toners for two-component developers.

[0006] Here, as the coloring material for coloring especially yellow, nitro type, azo type, stilbene azo type, diphenylmethane type, quinoline type, methine type, thiazole type, anthraquinone type, isoindolinone type, Anthrapyrimidine-based, flavanthron-based organic dyes or pigments, or chromate-based, cadmium-based, titanium yellow, yellow iron oxide-based, Hansa yellow-based, benzidine yellow-based, zinc chromate-based, aureolin-based inorganics Known are pigments or metal salts of acidic dyes, lake pigments represented by salts of basic dyes with phosphoric acid, molybdic acid, tungstic acid, and the like.

As the above-mentioned charge control agent, for example, a nigrosine dye is known to give a positive charge to the toner,
Known examples of materials that impart a negative charge to toners include chromium-containing monoazo complexes, chromium-containing salicylic acid compound complexes, chromium-containing organic dyes, metal-containing dyes, and nitrohumic acid (salt) anthraquinone diamine derivatives. However, these conventional charge control agents are mostly black substances or have poor compatibility or wettability with the binder resin, and further, they do not have good charge controllability for a long period of time because of their sublimability. Most of them are unsuitable for color electrophotographic toners or color electrostatic recording toners because they are substances.

Considering that the demand for obtaining two-color or multi-color copies from two-color or multi-color originals (including tables, graphs, and figures) has increased more and more in recent years, conventional charge control agents are not used. There's a problem. In addition, although the toner containing such a conventional charge control agent shows good developing characteristics at the initial stage, it has a short life and environmental stability (stability to changes in temperature and humidity) is poor, causing a decrease in image density. It has the drawback of causing fog and scumming.

Many of the above-mentioned conventional colorants and charge control agents are disclosed in Japanese Examined Patent Publication Nos. 48-25941 and 48-267.
No. 84, Japanese Patent Publication No. 49-20225, Japanese Patent Publication No. 50-14
No. 0137, Japanese Examined Patent Publication No. 142037, Japanese Examined Publication No. 50
-1402838, Japanese Patent Publication No. 46-43440, Japanese Patent Publication No. 48-30899, Japanese Patent Publication No. 49-46423, Japanese Patent Publication No. 49-26909, Japanese Patent Publication No. 49-15949, Japanese Patent Publication No. 49-134303, Japanese Patent Publication No. 57- It is disclosed in the gazettes such as No. 42860.

[0010]

As pointed out above, no yellow color toner has been found to be satisfactory in terms of color image reproducibility, image retention, safety and hygiene, etc. Is the actual situation. in addition,
Many of the conventionally known inorganic pigments have safety and health problems, and as a practical matter, it is impossible to use toners containing them in general copying machines, printers and the like. Similarly, some organic coloring materials have safety and health problems, and the usable coloring materials are limited. Even if there are no safety and health problems,
There are many problems with image retention. That is, many organic coloring materials undergo discoloration or fading over time due to exposure to ultraviolet rays and the like, and few are particularly satisfactory in terms of retaining color images. Commonly used monoazo compounds have weak coloring power, and among disazo compounds, benzidine yellow is generally used, but it is also reported that decomposition products have safety and health problems.

Therefore, a first object of the present invention is to provide a yellow color toner for developing an electrostatic latent image, which can obtain a uniform image density and hardly cause peripheral effects and fog. A second object of the present invention is to provide a yellow toner for developing an electrostatic latent image in a one-component or two-component developer which is suitable for high-speed development and has excellent durability and environmental stability. A third object of the present invention is to provide a yellow color toner for developing an electrostatic latent image which is not affected by changes in temperature and humidity and does not cause an offset phenomenon. A fourth object of the present invention is to provide a yellow color toner for developing electrostatic latent images which is excellent in safety and hygiene with respect to decomposition products.

[0012]

The present invention provides a yellow color toner for developing an electrostatic latent image containing a colorant and a binder resin as main components, and the colorant is represented by the following formula (I).

[Chemical 2] The compound represented by is used. And it is desirable that all of the colorants are compounds represented by the formula (I), but other yellow colorants may be used in combination within the range of 75% by weight or less of the colorant.

The compound represented by the above formula (I) is a colorant classified into "Pigment Yellow 180", which is a known substance per se, but this compound is a colorant for a color toner for developing an electrostatic latent image. The present inventors have not yet contacted the report that it was used as.

The present invention will be described in more detail below. As described above, the color toner of the present invention contains a yellow colorant and a binder resin as main components, but a charge control agent, a fluidity imparting agent and the like are generally added. The charge control agent is usually added internally to the toner, but the fluidity-imparting agent is preferably added externally to the toner particles.

As the binder resin, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-
Chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer Polymers (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.),
Styrene-methacrylic acid ester copolymer (styrene-
Methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α-chloromethyl acrylate copolymer, styrene- Acrylonitrile-styrene resin such as acrylate copolymer (styrene or a styrene-substituted homopolymer or copolymer), vinyl chloride resin, rosin-modified maleic acid resin, phenyl resin, epoxy resin, polyester resin, low Examples thereof include molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral, and the like, and polyester-based or styrene-based resins are particularly preferably used.

As the charge control agent, a nigrosine dye, a chromium-containing complex, a quaternary ammonium salt and the like are used, and these are properly used depending on the polarity of the toner particles. In the case of a color toner, a colorless or light color toner that does not affect the color tone of the toner is preferable, and examples thereof include a metal salt of salicylic acid or a metal salt of a salicylic acid derivative (Bontron E84, manufactured by Orient Co.). The charge control agent is added in an amount of 0.1 to 10 parts by weight, preferably 0.2 to 7 parts by weight, based on 100 parts by weight of the binder resin.

As the fluidity-imparting agent, fine particles of metal oxides such as silica, alumina, magnesia, zirconia, ferrite and magnetite, and those fine particles are used as silane coupling agents, titanate coupling agents, zircoaluminates, quaternary ammonium salts. , Surface-treated or coated with a treatment agent such as fatty acid, fatty acid metal salt, fluorine-based activator, solvent, polymer, fine particles of fatty acid or metal salt thereof such as stearic acid and zinc stearate, and fine particles thereof with the treatment agent. Surface-treated ones, polymer fine particles such as polystyrene, polymethylmethacrylate, and polyvinylidene fluoride, and those fine particles surface-treated or coated with the above-mentioned treating agent are used. The fluidity-imparting agent having an average particle size of 0.01 to 3 μm is used. The amount of the fluidity-imparting agent added is 0.01 to 7.0% by weight based on 100 parts by weight of the toner particles.
In particular, the range of 0.02 to 5% by weight is preferable. The mixing method of the toner particles and the fluidity-imparting agent is such that the powder is moved in a fluidized state at a high speed by an air flow or mechanical force so as not to substantially pulverize. The mixer is a high-speed flow type mixer, for example, a Henschel mixer, a UM mixer or the like.

As the method for producing the toner according to the present invention, various known methods or a combination thereof can be used. For example, in the kneading-grinding method, a binder resin and a colorant such as carbon black and necessary additives are mixed, and the mixture is heated and melted and kneaded by an extruder, a two-roll roll, a three-roll roll or the like, and after cooling and solidification. A toner is obtained by pulverizing with a pulverizer such as a jet mill and classifying with an air stream classifier. It is also possible to directly produce a toner from a monomer, a colorant, and an additive by a suspension polymerization method or a non-aqueous dispersion polymerization method.

The yellow color toner of the present invention can be used as a one-component developer, but is particularly suitable for a two-component developer used in combination with a carrier. The carrier used here is generally a core material whose surface is coated with a resin. As the core substance of the resin-coated carrier, iron powder, oxidized iron powder, ferrite, nickel and other magnetic substances can be used. The particle diameter of the core substance is 20 to 100 μm, preferably 3
About 0 to 60 μm is suitable.

Next, as the coating resin for the carrier coating, polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene and chlorosulfonated polyethylene; polyvinyl and polyvinylidene resins such as polystyrene and acrylic resins (eg polymethylmethacrylate). ), Polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight consisting of organosiloxane bonds Silicone resin such as silicone resin or its modified product (for example, alkyd resin, polyester, epoxy resin, polyurethane, etc. Fluorine resin such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene; polyamide; polyester such as polyethylene terephthalate; polyurethane; polycarbonate; amino resin such as urea-formaldehyde resin; epoxy Resin etc. are mentioned. Of these, acrylic resins, silicone resins or modified products thereof, and fluororesins, particularly silicone resins or modified products thereof, are preferable from the viewpoint of preventing the spent toner from adhering to the carrier. In addition, as a commercially available product of silicone resin (however, straight silicone resin), KR manufactured by Shin-Etsu Chemical Co., Ltd.
271, KR255, KR251, SR2400, SR2406 manufactured by Toray Silicon Co., Ltd., and modified silicone resins such as KR206 (alkyd resin modified product), KR3093 (acrylic resin modified product) and ES1001M (epoxy resin modified) manufactured by Shin-Etsu Chemical Co., Ltd. Product), SR2115 manufactured by Toray Silicon Co. (epoxy resin modified product),
SR2110 (alkyd resin modified product) and the like are available. The amount of the above-mentioned coating resin used is appropriately about 0.1 to 50 parts by weight, and more preferably 0.5 to 30 parts by weight, per 100 parts by weight of the carrier core material.

In order to obtain the simplest carrier particles, for example, a coating solution comprising 300 parts by weight of silicone resin solution (SR2406 manufactured by Toray Silicone Co., solid content 20%) and 1500 parts by weight of toluene is prepared. On the other hand, 5000 parts by weight of a ferrite carrier having an average particle size of about 50 μm was placed in a rotating disk type fluidized bed particle coating device, and the coating solution of the above formulation was sprayed under heating at 80 ° C. while flowing to obtain a coated product. The silicone film may be taken out from the coating apparatus and placed in a constant temperature bath and heated at 200 ° C. for 2 hours to cure the silicone film.

An appropriate amount of conductive substance can be added to the carrier coating layer. Specific examples of the conductive substance include the following (a) and (b). However, since the presence of carbon makes the yellow color toner dark, it is preferable to avoid adding carbon as much as possible. (A) White conductive material ECT-52 (TiO ₂ system) Titanium Industry Co., Ltd. KV400 (TiO ₂ system) Titanium Industry Co., Ltd. ECR-72 (TiO ₂ system) Titanium Industry Co., Ltd. ECTR-82 (TiO ₂ system) Titanium Industrial Co., Ltd. 500W (TiO ₂ system) Ishihara Sangyo Co., Ltd. 300W (TiO ₂ system) Ishihara Sangyo Co., Ltd. S-1 (TiO ₂ system) Ishihara Sangyo Co., Ltd. W-1 (SnO ₂ system) Mitsubishi Metal Corp. 23K (ZnO) ) Hakusui Chemical Co., Ltd. Conductive Zinc Flower No. 1 (ZnO) Honjo Chemical Co., Ltd. Conductive Zinc Flower No. 2 (ZnO) Honjo Chemical Co., Ltd. W-10 (TiO ₂ system) Mitsubishi Metals Company Dentor WK-100 ( Conductive fiber) Otsuka Chemical Co., Ltd. Dento WK-200 (conductive fiber) Otsuka Chemical Co., Ltd. Dentor WK-300 (conductive fiber) Otsuka Chemical Co., Ltd. MEC300 (SnO ₂ system) Teikoku Chemical Co., Ltd. MEC500 (SnO ₂ system) Imperialization (B) Carbon black Pearls 2000, VULCANXC-72 (manufactured by Cabot) Ketjen black EC / DJ500, Ketjen blabk EC / DJ600
(Lion Akzo) Denka black granular, Denka black powder (Denki Kagaku Co., Ltd.) CONDUCTEX975, CONDUCTEX SC (Colombua Carbon)

The amount of conductive material is 0.05 to 70 parts by weight, preferably 0.1 to 100 parts by weight of the silicone resin.
˜50 parts by weight is suitable, and if necessary, a silane coupling agent is added to the resin coating layer in order to improve the adhesive strength of the coating layer and further to improve the dispersibility of the conductive material. May be. The coating layer may be formed on the surface of the carrier particles by a method such as a spraying method or a dipping method as in the conventional case.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. All parts are by weight.

Example 1 Polyester resin 100 parts Yellow colorant represented by the above formula (I) 5 parts Charge control agent (E-84, manufactured by Orient Chemical Co.) 2 parts A mixture having a composition sufficient in a Henschel mixer After stirring and mixing, the mixture was heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes by a hot roll mill, cooled to room temperature, and the obtained kneaded product was pulverized and classified to obtain a yellow toner having a particle size of 5 to 20 μm. To 100 parts of this toner, 0.5 part of silica as an additive was mixed and stirred to obtain a toner of the present invention. next,
5 parts of this toner and iron powder carrier (TEF manufactured by Nippon Iron Powder Co., Ltd.
V200 / 300) was mixed with 95 parts to obtain a two-component developer. When the developer was set in a color electrophotographic copying machine (FT-3300) manufactured by Ricoh Co., Ltd. and developed, a clear high quality image was obtained, and the image did not change even after 100,000 images were printed, and the offset A good image was obtained without occurrence of When the toner charge amount was measured by the blow-off method, the initial charge amount was −21.4 μc / g, and the toner charge amount after running 100,000 sheets was −
The measured value was 19.8 μc / g, which was almost the same as the initial value. Also, in a high humidity environment of 35 ° C. and 90% RH,
Under a low-humidity environment of 18.1 μc / g and 10 ° C. and 15% RH, the charge amount was −19.6 μc / g, which was not so different from normal humidity, and an equivalent image was obtained. Further, when the copy image obtained by the image test was sandwiched between plus vinyl chloride mat (w) manufactured by Plus Co., Ltd. and stored at 50 ° C. for 24 hours, there was no fusion of the vinyl chloride mat toner and good vinyl chloride mat storage. Showed sex.

Comparative Example 1 A toner was obtained in the same manner as in Example 1 except that Rionol Yellow FGN-T (manufactured by Toyo Ink Mfg. Co., Ltd.) was used in place of the colorant used as the colorant in Example 1. ,
Further, a two-component type developer was obtained by the same method and an image test was conducted. As a result, a clear image having no fog was obtained as the initial image, but the image density was reduced to 0.65 from about 50,000 sheets, and the image became unclear. When the charge amount was measured in the same manner as in Example 1, the initial toner charge amount was -2.
It was 0.2 µc / g, but after 100,000 sheets, it was -12.4 µ.
It fell to c / g. Further, when an image test was carried out in a high humidity environment of 35 ° C. and 90% RH, the toner charge amount was reduced to −7.3 μc / g, and an unclear image with fog was obtained.

Comparative Example 2 Instead of the colorant used as the colorant of Example 1, S
Toner was obtained in the same manner as in Example 1 except that ymuller Fast Yellow 8GR (manufactured by Dainippon Ink and Chemicals, Inc.) was used, and a two-component developer was obtained by the same method,
An image test was performed. As a result, a clear image having no fog was obtained as the initial image, but after about 50,000 sheets, the image density was low at 0.68, offset development occurred, and the image became unclear. Further, when the toner charge amount was measured in the same manner as in Example 1, the initial toner charge amount was −20.8 μc /
Although it was g, it decreased to -11.7 μc / g after 100,000 sheets.

[0028]

According to the first and second aspects of the present invention, by using a specific colorant, an image having the same quality as the initial image can be obtained even after continuous copying, and there is almost no peripheral effect or fog. A stable triboelectric charging property can be obtained. In addition, a developer having excellent environmental stability was obtained, and a clear copy image was obtained. In addition, offset development does not occur.
Further, it is possible to provide a yellow toner excellent in safety and hygiene with respect to decomposition products.

Front page continuation (72) Inventor Michio Izumi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Yoshihisa Okamoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Hidefumi Gohara 1-3-6 Nakamagome, Ota-ku, Tokyo In Ricoh Company (72) Inventor Satomi Suzuki 1-3-3 Nakamagome, Ota-ku, Tokyo In Ricoh Company, Ltd.

Claims (2)

[Claims] 1. A yellow color toner for developing an electrostatic latent image, comprising a colorant and a binder resin as main components and the colorant being a compound represented by the following formula (I). [Chemical 1] 2. The yellow color toner for developing an electrostatic latent image according to claim 1, wherein the compound represented by the formula (I) accounts for at least 25% by weight of the total amount of the colorant.