JPH06242633A - Production of electrostatic charge developing toner - Google Patents

Abstract

PURPOSE:To provide the process for production of the electrostatic charge developing toner which has an excellent flow property, makes it possible to obtain high-density and bright images and has excellent offset resistance, release property, fixability and durability and the process for production of release agent particulates for production of the toner. CONSTITUTION:This process for production of the electrostatic charge developing toner consists of mixing the release agent particulates coated and/or impregnated with a vinyl polymer by adding a polymerizable vinyl monomer and a water-soluble polymn. initiator to a release agent emulsion and polymerizing the mixture into coloring resin particles and fixing the release agent particulates to the surfaces of the coloring resin particles. This process for production of the release agent particulates consists of adding and polymerizing the polymerizable vinyl monomer and the water-soluble polymn. initiator simultaneously or continuously or polymerizing the polymerizable vinyl monomer below the m.p. of the release agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner for electrostatic charge development used in electrophotography, electrostatic recording and the like, and a method for producing release agent fine particles for producing the toner.

[0002]

2. Description of the Related Art As means for developing an electrostatic latent image formed on an electrophotographic photoreceptor or electrostatic recording body, a method using a liquid developer (wet developing method) and a method using a binder resin dye,
A method in which a colorant such as a pigment and, if necessary, a release agent, a charge control agent, or the like is dispersed, or a one-component or two-component dry developer in which the toner is mixed with a solid carrier (dry development Law) and are generally adopted. Each of these methods has advantages and disadvantages, but at present, the dry development method is widely used.

In order to provide high image quality and high durability, the toner has a small particle size, a narrow particle size distribution, a smooth surface shape, and a charge control agent uniformly dispersed. Is required. That is, the particle size affects the resolution, sharpness, halftone reproducibility, etc., and a wide particle size distribution causes selective development of a specific particle size.
Difficulty in durability. If the surface shape is not smooth, due to the stress during stirring in the developing area, partial pulverization occurs on the surface and ultrafine powder is generated, which in the two-component type developer fuses to the carrier and deteriorates charging. In the one-component developer, the toner is fused to the toner thin film member, which causes white stripes. In addition, non-uniform distribution of the charge control agent in the toner causes scumming.

A conventional general method for producing a toner, that is, a method in which a resin, a dye / pigment, a release agent and a charge control agent are melt-kneaded and then pulverized and classified by a mechanical or air collision pulverizer. When a toner having a small particle size and a narrow particle size distribution is produced, the production capacity and the yield are significantly reduced and the cost is increased. The influence of the non-uniformity of the dispersion of the property-imparting agent such as the charge control agent and the release agent added therein becomes remarkable.

On the other hand, these dry toners are adhered to an electrostatic image or transferred to a support such as paper and then fixed to form a visible image. There are various methods for fixing the toner, but the heat roller fixing method is preferably generally used from the viewpoints of thermal efficiency and fixing speed. However, the hot roller fixing method causes problems such as hot offset and generation of nail marks. Hot offset is a phenomenon in which molten toner is fused to a heat roller and re-transferred to a support such as transfer paper.Nail marks are separations provided to separate the support such as paper from the fixing roller. This is a phenomenon in which fused toner on an image adheres to the nail and a white line-shaped defective portion is generated in the image.

In order to prevent these problems, a method of applying a releasing liquid such as silicone oil to the fixing roller is used. Although this method is effective, there is a problem that the apparatus for applying the releasing liquid to the fixing roller is required, the apparatus becomes complicated, and an expensive material such as silicone oil is also required, resulting in an increase in cost. Further, there is a problem in that the releasing liquid such as silicone oil is heated to evaporate and contaminate the surroundings to cause an unpleasant odor.

As a method for preventing hot offset of the toner without using silicone oil, a method of mixing a releasing agent such as a low molecular weight polyolefin wax into the toner resin has been proposed (JP-A-49-65231).
issue). Those existing near the toner surface act as an effective releasing agent, but it is necessary to knead 5 to 10% by weight of the releasing agent into the toner in order to obtain a sufficient offset preventing effect. . These release agents have poor compatibility with the binder resin of the toner, and it is difficult to uniformly knead a large amount of the release agent, and the release agent added in a large amount lowers the blocking resistance, However, problems such as filming on carriers and the like, and spent are generated.

To solve these problems, Japanese Patent Laid-Open No. 63-4
1861, JP-A-63-244053, JP-A-63
No. 300425 discloses a method of providing a layer containing a release agent on the outer layer of the toner. Further, the dispersion polymerization method is effective as a method for producing a toner having a small particle size and a uniform particle size distribution. The dispersion polymerization method is a method of polymerizing in a solvent in which a monomer is dissolved but a polymer produced therefrom is not dissolved in the presence of a dispersion stabilizer soluble in the solvent, and a resin having a small particle size and a narrow particle size distribution. Although this is an effective method for producing particles, it is difficult to incorporate a property-imparting agent such as a release agent into the particles, so the method of fixing the release agent to the resin particle surface yields an oil-free toner. It is an effective method for

However, in the method of using a fine powder of a mixture of a polyolefin as a release agent and another thermoplastic resin as disclosed in JP-A-63-41861 and JP-A-63-244035, a fine powder is obtained. Not only is it extremely difficult to obtain it, but the viscosity of the polyolefin exposed on the toner surface lowers the fluidity and the transferability from the photoreceptor to the transfer paper and the like. Therefore, it becomes difficult to obtain a clear image with high density. The method using a wax emulsion disclosed in JP-A-63-300245 makes it easy to obtain fine wax particles, but the effect of the emulsifier used in the emulsion is added, and the fluidity and transferability are further lowered.

Further, Japanese Patent Application Laid-Open No. 1-257853 discloses a method of fixing resin fine particles containing polypropylene prepared by soap-free emulsion polymerization on the surface of a suspension-polymerized toner. In this method, soap-free emulsion polymerization is used. It is difficult to make resin fine particles containing polypropylene, and even if polypropylene is contained, the amount is very small. In these fine particles, the ratio of non-releasing resin to polypropylene acting as a mold release agent is extremely large, There is a low possibility that the agent is exposed on the surface, the releasing agent cannot be eluted even by heating, and there is a problem that the releasing effect is not exhibited.

As described above, according to the conventional technique, the toner having the release agent fine particles adhered to the surface has a lowered fluidity / transferability, and the fluidity / transferability and the releasability cannot be compatible with each other. It was difficult to obtain a clear image with the density.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art, to obtain a clear image with excellent fluidity and high density, and to provide offset resistance, releasability, fixing property and durability. (EN) It is an object to provide an excellent method for producing a toner for electrostatic charge development, and an industrially advantageous method for producing fine particles of a release agent for producing the toner.

[0013]

DISCLOSURE OF THE INVENTION The present invention relates to a release agent in which a vinyl polymer is coated and / or impregnated by adding a polymerizable vinyl monomer and a water-soluble polymerization initiator to a release agent emulsion and polymerizing the emulsion. Agent fine particles, mixed with colored resin particles,
A method for producing a toner for electrostatic charge development, characterized in that the release agent fine particles are fixed to the surface of a colored resin particle,
Further, the method for producing the release agent fine particles is characterized in that after the nitrogen substitution and the temperature rise, the polymerizable vinyl monomer and the water-soluble polymerization initiator are added to the release agent emulsion at the same time or continuously to perform polymerization. The mold release agent fine particles are provided, wherein the temperature at the time of adding the polymerizable vinyl monomer and the water-soluble polymerization initiator to the mold release agent emulsion for polymerization is not more than the melting point of the mold release agent. A method of manufacturing the same is provided.

That is, according to the present invention, the release agent fine particles in which the vinyl polymer is coated and / or impregnated on the surface of the resin particles containing the colorant, and the electrostatic charge developing toner in which the release agent fine particles are fixed. The present invention relates to a manufacturing method of. In general,
The release agent present on the toner surface is plasticized by heat and pressure applied in the copying process to generate tackiness, which increases the adhesive force between the toner particles and reduces fluidity and transferability. By fixing the impregnated release agent fine particles to the surface of the toner (colored resin particles), it is possible to prevent the toners from adhering to each other due to heat and pressure, and the release agent can be easily applied to the toner by heating during fixing. Since it elutes on the surface, it is possible to obtain a toner for electrostatic charge development having excellent fluidity and transferability, and excellent releasability.

The colored resin particles used in the present invention may be particles obtained by kneading and pulverizing a colorant and a resin, or particles obtained by suspension polymerization of a polymerizable monomer containing a colorant. However, particles obtained by coloring resin particles obtained by the dispersion polymerization method are preferable because particles having a small particle diameter with a narrow particle diameter distribution can be easily obtained. Dispersion polymerization is a method in which a polymerization initiator is added in the presence of a dispersion stabilizer which is soluble in a solvent in which a vinyl monomer as a raw material is dissolved but a polymer produced therefrom is not dissolved. Vinyl monomers include styrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, divinylbenzene,
Known binder resins for toner such as ethylene glycol dimethacrylate and butanediol dimethacrylate are used. A chain transfer agent such as n-dodecyl mercaptan may be used to control the molecular weight.

As the polymerization initiator, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide,
Lauroyl peroxide or the like is used. The solvent is preferably a hydrophilic solvent such as methanol or ethanol. If necessary, water or a soluble lipophilic solvent may be mixed with these hydrophilic liquids. As the dispersion stabilizer, a homopolymer of a monomer having a hydrophilic group or a copolymer of this and another monomer, which is soluble in a hydrophilic organic solvent, is preferably used. Examples of the monomer having a hydrophilic group include (meth) acrylic acid, fumaric acid, maleic acid, maleic anhydride, 2-hydroxyethyl (meth) acrylate, vinyl acetate, (meth) acrylamide, vinylpyridine and vinyl. Pyrrolidone, vinylimidazole, ethyleneimine and the like can be mentioned.

The resin particles are manufactured by dissolving a polymer dispersion stabilizer in a hydrophilic organic liquid, adding one or more kinds of monomers, and then charging the reaction vessel with an inert gas such as nitrogen or argon. After the replacement, the polymerization can be carried out by adding a polymerization initiator and stirring the mixture so that the flow in the tank becomes uniform while heating at a temperature corresponding to the decomposition rate of the initiator used for polymerization.

The obtained resin particles can be colored resin particles by fixing a colorant on the surface, but it is preferable to color the resin particles with a dye from the viewpoint of fixing property. For dyeing, it is preferable to disperse the resin particles in an organic solvent that does not dissolve the resin particles, and before or after dissolving the dye in the solvent, maintain the liquid temperature below the glass transition temperature of the resin particles and stir. This makes it possible to efficiently produce a toner in which the dye penetrates into the resin particles. Alternatively, the dye may be directly added to the slurry obtained after the polymerization is completed by dispersion polymerization or the like, and the mixture may be heated and stirred under the above conditions. The ratio of the dye to the resin particles is arbitrarily selected according to the degree of coloring, but is usually 1 to 20 parts by weight based on 100 parts by weight of the resin particles.

The dye used is, for example, SP in the dyeing solvent.
When alcohols such as methanol and ethanol having a high value are used and a styrene-acrylic resin having an SP value of about 9 is used as the resin particles, examples of dyes that can be used include the following dyes. C. I. SOLVENT YELLOW (6,9,1
7, 31, 35, 100, 102, 103, 105) C.I. I. SOLVENT orange (2,7,1
3, 14, 66) C.I. I. SOLVENT RED (5, 16, 17,
18, 19, 22, 23, 143, 145, 146, 1
49, 150, 151, 157, 158) C.I. I. SOLVENT VIOLET (31, 3
2, 33, 37) C.I. I. SOLVENT BLUE (22, 63, 7
8, 83-86, 91, 94, 95, 104) C.I. I. SOLVENT GREEN (24, 25) C.I. I. SOLVENT BROWN (3,9) etc.

Further, the release agent fine particles coated and / or impregnated with the vinyl polymer are easily produced by adding a polymerizable vinyl monomer to the release agent emulsion and polymerizing with a water-soluble polymerization initiator. can do. By using the release agent emulsion, the polymerizable vinyl monomer can be stably polymerized, and particles having a fine particle diameter that can be uniformly attached to the colored resin particles can be obtained. Further, by coating the release agent emulsion particles with a vinyl polymer, the adverse effect of the emulsifier contained in the release agent fine particles can be removed.

The release agent referred to herein may be any substance as long as it is a substance which is melted at the time of fixing the heat roller and has an effect of preventing the adhesion of the toner on the heat roller and the material to be fixed, that is, the above-mentioned offset phenomenon. It means all substances which have a protective effect. Specific examples of these substances include low molecular weight polyolefins having a number average molecular weight of 1,000 to 20,000 such as polypropylene, polyethylene, polypropylene oxide, and polyethylene oxide, natural waxes such as candelilla, carnauba, rice, wood wax, jojoba, montan, ceresin. , Natural mineral wax such as ozokerite,
Petroleum waxes such as paraffin, microcrystalline and petrilactam, and modified waxes thereof. Solid higher fatty acids such as palmitic acid, stearic acid and behenic acid, higher stearic acid such as calcium stearate, aluminum stearate, calcium palmitate and zinc palmitate, alkali metal salts, zinc salts, aluminum salts, octadecyl stearate, glycerin monostearate Higher fatty acid ester such as lauric acid amide, stearic acid amide, N, N′-ethylenebisolefinic acid amide, N,
Amides such as N-ethylenebisstearic acid amide. Examples thereof include ketones such as diheptadecyl ketone and diundecyl ketone.

These releasing agents are melt-mixed with 10% to 30% by weight of nonionic, anionic or cationic one or two types, and hot water having a temperature not lower than the melting point of the releasing agent is forcibly stirred. Can be gradually added to obtain a release agent emulsion. Further, polyhydric alcohol is added to water to form a three-component system of water-polyhydric alcohol-surfactant,
A release agent may be added to this, heated to the melting temperature of the release agent, forcibly stirred, and water may be added to this to produce an emulsion. Alternatively, a nonionic surfactant having a phase inversion temperature higher than the melting point of the release agent may be used, and the release agent may be forcibly stirred and emulsified in water at around the phase inversion temperature, followed by cooling and then production. A homomixer, a disper mixer, a homogenizer, etc. are used as a device for forcibly stirring.

Next, one or more polymerizable vinyl monomers are added to the release agent emulsion prepared by a conventional method, and the emulsion is polymerized with a water-soluble polymerization initiator. As the vinyl-based monomer used at this time, styrenes such as styrene, α-methylstyrene and parachlorostyrene, (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate and butyl (meth) acrylate, Vinyl acetates such as vinyl acetate and vinyl propionate, vinyl halides such as vinyl chloride and vinylidene chloride, vinyl nitriles such as acrylonitrile and methacrylonitrile, vinyl ethers such as vinyl ethyl ether, and 2 of these monomers. Combinations of more than one, especially trifluoroethyl (meth) acrylate,
Monomers such as tetrafluoropropyl (meth) acrylate and octafluoropentyl (meth) acrylate are preferably used because of their low surface energy.

These monomers are 0.5% by weight with respect to the release agent.
Polymerization is carried out by adding -15 wt%, preferably 1 wt% -10 wt%. If it is less than 0.5% by weight, the amount of the release agent particles coated is small and the effect of improving the fluidity and transferability is small. If it is more than 15% by weight, the release agent is inhibited from elution at the time of fixing and the releasing effect is obtained. descend. Further, these monomers or monomer mixtures are selected so that the Tg of the resulting polymer will be in the range of 60 ° C to 100 ° C. If the Tg is less than 60 ° C, the heat resistance is lowered to cause blocking of the toner during storage, and if the Tg is higher than 100 ° C, it is difficult to melt the resin coated during fixing and the releasability is lowered.

As the polymerization initiator used in the polymerization of these vinyl monomers, a water-soluble polymerization initiator which is usually used is used, but when the emulsifier used in the release agent emulsion is nonionic and / or anionic, it is persulfated. Acidic polymerization initiators such as potassium, sodium persulfate and ammonium persulfate are preferable, and basic polymerization initiators such as 2,2′-azobis (2-amidinopropane) dihydrochloride are preferable when the emulsifier is a cation. . These polymerization initiators are used in an amount of 0.5 to 20% by weight based on the vinyl monomer.

The polymerization is carried out by adding a vinyl monomer and a polymerization initiator to the release agent emulsion after heating and nitrogen substitution, and the polymerization is carried out by adding the vinyl monomer and then the polymerization initiator. The effect on fluidity, transferability and releasability varies depending on the time until the start of. That is, if the vinyl monomer is added and polymerization is started immediately, the effect of improving the fluidity / transferability is great, and if the time from the addition of the vinyl monomer to the initiation of polymerization is long, the fluidity / transferability is improved. The effect of improving is reduced. However, there is no great difference in releasability between the two. This is because if the time from the addition of the vinyl monomer to the initiation of polymerization is short, the proportion of the vinyl polymer coating the release agent fine particles is high, and if the time is long, the proportion of the vinyl polymer impregnated inside the release agent is high. It is thought to be due to the increase. Therefore, it is preferable to set the polymerization condition operation such that the polymerization is started immediately after the vinyl monomer is added.

It is preferable to carry out the polymerization at a temperature not higher than the melting point of the release agent. If the polymerization temperature is higher than the melting point of the release agent, the release agent fine particles are coalesced and the particles increase, which is not preferable.
Usually, the polymerization may be carried out at 50 ° C to 80 ° C. Agitation during polymerization may be gently stirred at 50 rpm to 300 rpm. The concentration of the release agent emulsion used for polymerization is 10
The amount may be from 50% by weight to 50% by weight, and if the polymerization temperature, stirring temperature, and stirring conditions are appropriately set, aggregation will not occur.

The release agent emulsion which has been subjected to the polymerization treatment can be uniformly adhered to the surface of the colored resin particles by mixing the release agent fine particles with the colored resin particle dispersion liquid. Although the adhesion of the release agent particles to the colored resin particles may occur simply by mixing, they can be firmly adhered by any of the following methods. As the attachment method, (1) a method of adding an acid or an alkali to adjust the pH, (2) a method of adding an anionic surfactant or a cationic surfactant, (3)
There is a method of adding an electrolyte. By these methods,
By properly setting the conditions, it is possible to adhere uniformly.

The colored resin fine particle dispersion liquid to which the release agent fine particles are evenly attached is preferably heat-treated in order to prevent the release agent fine particles from being detached in the subsequent step. 40 heat treatment
A toner having a release agent layer to which the release agent fine particles are firmly adhered can be produced by washing in the range of 70 to 70 ° C. and then washing and drying. If necessary, the colored resin fine particles to which the release agent fine particles are adhered may be washed and dried with or without heat treatment, and then mechanical impact force may be applied to fix the release agent fine particles to produce a toner. As a method of applying a mechanical impact force, there are a method of giving an impact by a blade rotating at a high speed, a method of being injected into a high-speed air flow to accelerate particles to collide with each other, or a method of colliding particles with a collision plate. Specific devices include a mechanofusion (made by Hosokawa Micron), a type I mill (made by Nippon Pneumatic Mfg. Co., Ltd.), a hybridization system (made by Nara Machinery Co., Ltd.), an automatic mortar and the like.

The ratio of the release agent fine particles to the colored resin particles is 0.5% by weight to 5% by weight, preferably 1% by weight to 3% by weight. If it is less than 0.5% by weight, the releasing effect is not sufficient, and if it is more than 5% by weight, fluidity and transferability are deteriorated. If necessary, the charge control agent fine particles and the chargeable resin fine particles may be fixed to the surface of the toner having the release agent layer.
Thermal energy or mechanical impact force is used as the fixing method. Further, the toner having a releasing agent layer may be used as a mixture with a fluidizing agent. The fluidizing agent is silica, hydrophobic silica,
Known materials such as titanium oxide, zinc oxide and zinc stearate are used. The amount of the fluidizing agent added is 0.1% to 5% by weight of the toner, and preferably 0.5% to 3% by weight. As a mixing method, a general mixing device such as a V blender or a ball mill may be used.

When the toner of the present invention is used as a two-component developer, it is used as a mixture with a carrier. As the carrier that can be used in the present invention, known carriers can be used, and examples thereof include magnetic powders such as iron, magnetite, hematite and ferrite, and glass beads. The particle size of these powders is 50 μm to 200 μm.
In particular, a carrier in which these powders are coated with a silicone resin is preferably used. 0.5 toner for carrier
Add 5% by weight to 5% by weight, and mix with the general mixing device mentioned above to prepare a developer.

[0032]

EXAMPLES Parts and% in the examples represent parts by weight and% by weight. Production Example of Release Agent Emulsion 10 parts of carnauba wax (melting point: 78 to 84 ° C.) and 2 parts of polyoxyethylene nonylphenyl ether were placed in a beaker, and heated and stirred at 85 ° C. to melt-mix. 90 to this
28 parts of ion-exchanged water heated to 0 ° C. was added with vigorous stirring. This was kept at 85 ° C. and stirred for 30 minutes with a homomixer to obtain an emulsion. After cooling, ion-exchanged water was added to adjust the solid content concentration to 20%. Particle size of this emulsion Laser scattering type particle size meter (DLS700 made by Otsuka Electronics)
The volume average diameter was 0.12 μm and the number average diameter was 0.11 μm.

Production Example of Release Agent Fine Particle Emulsion (1) 100 parts of the above emulsion was weighed into a 4-necked flask equipped with a stirrer, a cooling pipe and a nitrogen introducing pipe, and the liquid temperature was 60 ° C.
After nitrogen substitution, 0.8 part of cyclohexyl methacrylate and 0.04 part of potassium persulfate dissolved in 2 parts of ion-exchanged water were added successively. Polymerization was completed by heating and stirring at the same temperature for 8 hours. The particle size of this emulsion is 0.14 for the average polymerization size.
The number average diameter was 0.12 μm. Further, the degree of polymerization of the added monomer was measured by the dry weight method to be 78.
%Met.

Production Example of Release Agent Fine Particle Emulsion (2)
~ (6) A release agent fine particle emulsion was produced in the same manner as in Polymerization Example (1), except that the vinyl monomer, the amount added, the amount used of the polymerization initiator and the polymerization method shown in Table 1 below were used.

[Table 1] (*) Production example except that after the monomer was added, the mixture was stirred at room temperature for 5 hours to allow the wax fine particles to absorb the monomer, then nitrogen substitution was performed and the temperature was raised, and then potassium persulfate aqueous solution was added to initiate polymerization. Same as (1).

Table 2 below shows the properties and the like of each emulsion obtained in Production Examples (1) to (6) of the release agent fine particle emulsion.

[Table 2] (*) After polymerization, store at room temperature for 1 month and check for sediment.
The particle size is measured using suspended particles. The particle size increases as the amount of monomer increases. Since the particle size increases more than the calculated amount, some aggregation occurs, but stability,
There is no problem in terms of adhesion of fine particles. If the polymerization temperature is higher than the melting point of the wax, agglomeration will occur remarkably, resulting in poor stability. The polymerization rate is about 80% regardless of the amount and type of the monomer.

Production Example of Colored Resin Particles Core particles were produced by the dispersion polymerization method as described below. Stirring blades,
In a 500 cc three-necked flask equipped with a condenser, 320 g of methanol was added, and 6.4 g of polyvinylpyrrolidone (average molecular weight 40,000) was added little by little while stirring,
It was completely dissolved. Further, 25.6 g of styrene, 6.4 g of n-butyl methacrylate, and 0.2 g of 2,2'-azobisisobutyronitrile were added and completely dissolved. While stirring, purge the inside of the flask with dry argon gas,
It was left for 1 hour. 20 in a constant temperature water bath at 60 ℃ ± 0.1 ℃
Polymerization was started while stirring at a stirring speed of 0 rpm. After 15 minutes of heating, the liquid started to become cloudy, and it remained a cloudy and stable dispersion even after 20 hours of polymerization. It was confirmed by gas chromatography that the polymerization rate reached 98% using ethylbenzene as an internal standard. When the obtained dispersion liquid was cooled and centrifuged at 2000 rpm with a centrifuge, the polymer particles were completely settled and the liquid at the top was transparent. The supernatant was removed and 200 g of methanol was added, and the mixture was washed with stirring for 1 hour. The operation of washing with centrifugally separated methanol was repeated, and finally, washing with water was carried out, followed by filtration with a 1 μm microfilter. It was confirmed that the filtrate was transparent and there were no particles of 1 μm or less. The filtered product was air dried for one day and night, and dried under reduced pressure at 50 ° C. for 24 hours to obtain white powder of styrene / n-butyl methacrylate copolymer particles in a yield of 95%. The volume average particle diameter of the obtained particles was 7.0 μm, and the weight fraction of the polymer particles (A) having a particle diameter of 5.25 to 8.75 μm was 98%. The Tg of the resin was 65 ° C. Oil black 803 (manufactured by Orient Chemical Co., Ltd.) 1 g in 200 cc of methanol
Of the polymer particles (A) in the filtrate after dissolving
g was added and dispersed, and the mixture was heated with stirring at 50 ° C. for 1 hour. Then, the dispersion was cooled to room temperature, filtered, and dried to obtain colored resin particles.

Example 1 30 parts of the colored resin particles were mixed with 70% 50% aqueous methanol solution.
And then dispersed. To this, 3.7 parts of the emulsion of Production Example (1) (0.6 parts of wax content) was added and stirred, and then 10 parts of a 0.4% stearinamine acetate aqueous solution was added and stirred. When the wax-adhered particles were observed with an optical microscope, the wax particles were uniformly adhered to the surface of the colored resin particles. This dispersion was heated and stirred at 50 ° C. for 30 minutes to immobilize wax fine particles. The liquid was subjected to absorption filtration, redispersion in a 50% aqueous methanol solution, washed twice, suction filtered, and dried under reduced pressure at 50 ° C. to obtain a toner powder. 2 parts of this toner and 0.02 part of hydrophobic silica were mixed with a mixer. This was mixed with 98 parts of a silicone-coated ferrite carrier with a Turbula mixer to obtain a developer. Using this developer, image evaluation and transfer rate measurement were performed by PPC (Imagio 420, manufactured by Ricoh) without applying silicone oil as a release agent. For the transfer rate, the entire surface is developed in black, the machine is stopped during the transfer, the toner in the untransferred area and the transferred area on the photoconductor is transferred to an adhesive paper of known weight and the area is weighed, and the [(untransferred area is Toner weight-toner weight of transfer part)
/ Weight of toner in untransferred portion] × 100 was taken as the transfer rate.

Comparative Example 1 A toner and a developer were prepared in the same manner as in the example using 3.7 parts (solid content 0.74 part) of the original release agent emulsion in which vinyl monomer was not added and polymerized. And evaluated.

Comparative Example 2 320 parts of ion-exchanged water and 0.4 part of potassium persulfate were weighed in a four-necked flask equipped with a stirrer, a cooling tube, and a nitrogen introduction tube, and nitrogen substitution was performed to raise the temperature to 70 ° C. Keep low molecular weight polypropylene (Viscole 660p, Sanyo Kasei) 12
80 parts of styrene added with 1.0 part of styrene and 1.6 parts of methacrylic acid were added and polymerization was carried out at 70 ° C. for 8 hours. As a result, a large amount of lumps and agglomerates were generated, which were removed by centrifugal sedimentation and the suspended portion was collected and adjusted to a solid content concentration of 5%. The volume average diameter of the suspended portion is 0.43 μm, and the number average diameter is 0.2.
It was 1 μm. 14.8 parts of this dispersion (solid content 0.7
4 parts) and toners and developers were prepared and evaluated in the same manner as in the examples.

Example 1 using the wax emulsions of Production Examples (2) to (6) and the emulsions of Comparative Examples 1 and 2
A toner developer was prepared and evaluated in the same manner as in. The results are shown in Table 3 below.

[Table 3]

Copy Test Method (Releasability) An entire black (black solid) image was copied and the generation state of nail marks on separated nails (length of nail marks) was evaluated on a scale of 5 levels. 5 = No nail marks 4 = Nail marks less than 1 mm 3 = Nail marks 1 mm or more and less than 10 mm 2 = Nail marks 10 mm or more and less than 20 mm 1 = Nail marks 20 mm or more A drawing tester was used and the detached state of the image was evaluated on a 5-point scale. 5 = Most of the drawn portion is not peeled off. 4 = The drawn portion is peeled off like dots. 3 = The drawn portion is peeled off in a broken line shape. 2 = All the drawn parts are peeled off, and the width of peeling is narrow. 1 = All the drawn parts were peeled off, and the width of peeling was wide. The judgment is based on the limit sample. (Image Density) The reflection density of a circular image having a diameter of 10 mm was measured with a Macbeth densitometer. (Sharpness of image) The dot image was observed with an optical microscope, and the state of the image was evaluated in five levels. 5 = Toner is present only in the dot portion and the contour is clear. 4 = Most of the toner is present in the dots, but the outline is slightly unclear. 3 = A lot of toner is present in the dot portion, but the contour is unclear. 2 = Toner scattering is large, but the presence of dots cannot be determined. 1 = Toner scattering is so large that the presence of dots cannot be determined. The judgment is based on the limit sample.

Test Results (1) A toner using an emulsion polymerized by adding fluoroalkyl methacrylate as a releasing agent has a transfer property,
It had excellent releasability. (2) The transfer rate was not improved even if the amount of the monomer added to the release agent emulsion was increased. On the contrary, there was a tendency to decrease (Example 3). (3) Transferability could be significantly improved by adding and polymerizing a fluorine-free monomer such as benzyl methacrylate to the release agent emulsion (Example 4). (4) The toner using the releasing agent emulsion obtained by polymerizing the releasing agent particles after absorbing the monomer did not change the releasing property, but the transferability was slightly lowered (Example 5). (5) The toner using the release agent emulsion, in which the polymerization temperature at the time of adding the monomer to the release agent emulsion and performing the polymerization was not less than the melting point of the release agent, had reduced releasability (Example 6). . (6) The toner using the untreated release agent emulsion showed a large decrease in transfer rate (Comparative Example 1). (7) The toner using the emulsion of Comparative Example 2 had a good transfer rate but had no releasability.

[0043]

INDUSTRIAL APPLICABILITY According to the present invention, a toner for electrostatic charge development capable of obtaining a clear image having excellent releasability, transferability and durability, and release agent fine particles for producing the same can be efficiently produced by a simple method. Can be manufactured well.

Claims (3)

[Claims] 1. Release agent fine particles coated and / or impregnated with a vinyl polymer by adding a polymerizable vinyl monomer and a water-soluble polymerization initiator to a release agent emulsion and polymerizing the release resin emulsion with colored resin particles. A method for producing a toner for electrostatic charge development, which comprises mixing the release agent particles and fixing the release agent particles to the surface of the colored resin particles. 2. The method according to claim 1, wherein after the nitrogen substitution and the temperature rise, the polymerizable vinyl monomer and the water-soluble polymerization initiator are simultaneously or successively added to the release agent emulsion for polymerization.
A method for producing the release agent fine particles as described above. 3. The temperature at which the polymerizable vinyl monomer and the water-soluble polymerization initiator are added to the releasing agent emulsion and polymerized, is not higher than the melting point of the releasing agent. Method for producing fine particles of release agent.