JP2005134411A - Method for manufacturing polymerized toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient method for manufacturing polymerized toner having extremely sharp distribution of the particle size and little production amount of fine powder. <P>SOLUTION: The method for manufacturing polymerized toner includes steps of dispersing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant into liquid drops in an aqueous medium containing fine particles of a water-insoluble inorganic compound as a dispersant prepared by the reaction of two kinds of water-soluble inorganic compounds in a water phase, and then polymerizing the drops to produce color polymer particles. The fine particles of a water-insoluble inorganic compound are produced by bringing an aqueous solution of one inorganic compound of the two kinds of water-soluble inorganic compounds into contact with a solid material of the other inorganic compound and allowing them to react with each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a polymerized toner comprising colored polymer particles, and more particularly to an efficient method for producing a polymerized toner having a very small amount of fine powder and a very sharp particle size distribution. The production method of the present invention is particularly suitable as a production method of a polymerized toner having a small particle diameter having a volume average particle diameter in the range of about 4 to 9 μm.

  In image forming apparatuses such as electrophotographic and electrostatic recording copying machines, laser beam printers, and facsimiles, a developer is used to visualize the electrostatic latent image formed on the photoreceptor. . The developer contains, as a main component, colored particles in which a colorant, a charge control agent, a release agent, and the like are dispersed in a binder resin. The colored particles are generally called toner or toner particles.

  The toner is roughly classified into a pulverized toner obtained by a pulverization method and a polymerized toner obtained by a polymerization method. In the pulverization method, a thermoplastic resin is melt-kneaded with additive components such as a colorant, a charge control agent, and a release agent, pulverized, and classified to obtain pulverized toner as colored resin particles. The pulverized toner has an indefinite particle shape and a broad particle size distribution. Moreover, the pulverized toner generates a large amount of fine powder by pulverization.

  The toner desirably has a spherical shape and a sharp particle size distribution in order to form a high-definition and high-quality image. Further, from the viewpoint of toner properties such as print density, resolution, fog, and cleaning properties, it is not preferable that a large amount of fine powder that is considerably smaller than a predetermined average particle diameter is present. In the pulverized toner, fine particles can be removed by classification to narrow the particle size distribution. However, the yield decreases and the production efficiency deteriorates.

  In the polymerization method, a polymerizable monomer composition containing a polymerizable monomer, a colorant, and various additive components is dispersed in fine droplets in an aqueous medium, and then polymerized by a polymerization method. Polymerized toner is obtained as coalesced particles. Thus, in the polymerization method, colored polymer particles are obtained by a droplet forming (also referred to as “granulation”) step of a polymerizable monomer composition in an aqueous medium and a subsequent polymerization step. After the polymerization step, the produced colored polymer particles are recovered through a post-treatment step including washing, filtering and drying.

  According to the polymerization method, colored polymer particles having a spherical shape and a sharp particle size distribution can be produced. Further, according to the polymerization method, after the polymerization, the polymerizable monomer for shell is further polymerized in the presence of the generated colored polymer particles, and the colored polymer particles having a core-shell structure (“core-shell type” Colored polymer particles ”). While lowering the glass transition temperature of the polymer component constituting the core particle and increasing the glass transition temperature of the polymer constituting the shell, a polymer toner having excellent storage stability (blocking resistance) and low-temperature fixability can be obtained. Can be manufactured.

  Furthermore, according to the polymerization method, colored polymer particles having a volume average particle diameter of 10 μm or less, preferably 4 to 9 μm, and a small particle diameter can be easily produced. Therefore, the polymerized toner can form a high-definition and high-quality image, and is suitable for high-speed printing and full color.

  As described above, the polymerized toner having a small particle diameter plays an extremely important role in forming a high-definition and high-quality image. However, various problems have arisen as the particle size of the polymerized toner is reduced. In order to reduce the particle size of the polymerized toner, in the droplet forming step prior to the polymerization step, the aqueous medium containing the polymerizable monomer composition is agitated with a high shearing force by a stirrer to produce a polymerizable monomer composition. It is necessary to disperse objects as fine droplets. However, when the droplet size of the polymerizable monomer composition is reduced, the viscosity of the dispersion becomes very high, and it becomes difficult to form the droplet, and the processing efficiency by the stirrer decreases.

  Moreover, as the polymerized toner is reduced in particle size, the amount of fine powder generated increases rapidly, and it becomes difficult to sharpen the particle size distribution to a high degree. If a polymerized toner having a high fine powder content and a particle size distribution that is not sufficiently sharp is used, fogging increases and the print density decreases. On the other hand, if the amount of fine powder is large, it is necessary to classify the colored polymer particles obtained after polymerization and remove the fine powder, so that the treatment is complicated and the cost is high. Therefore, in order to form higher-definition and high-quality images, establishment of a technology for efficiently producing polymerized toners with an average small particle size, a very sharp particle size distribution, and a very small content of fine powder Is required.

  In the polymerization method, droplet formation of a polymerizable monomer composition and a polymerization reaction are performed in water or an aqueous medium mainly composed of water. A dispersant (also referred to as “dispersion stabilizer”) is used for stabilizing the dispersion of the above. That is, in the polymerization method, the polymerizable monomer composition is generally dispersed in fine droplets in an aqueous medium containing a dispersant, and then polymerization is performed. The dispersant adheres to the droplet surface of the polymerizable monomer composition, and enhances the dispersion stability of the droplet during the formation of the droplet and during the polymerization. Dispersants are generally classified into water-soluble polymers that form a protective colloid layer to develop a repulsive force due to steric hindrance and poorly water-soluble inorganic compounds that develop a static repulsive force to stabilize dispersion. Separated.

  As water-soluble polymers used as a dispersant, for example, polyvinyl alcohol, methyl cellulose, and gelatin are known. However, when the polymerizable monomer composition is dispersed in fine droplets in an aqueous medium containing a water-soluble polymer and then polymerized, the amount of fine powder generated increases, and the colored polymer particle particles The diameter distribution is broad. In addition, it is difficult to remove the water-soluble polymer adhering to the surface of the colored polymer particles by post-treatment such as washing after the polymerization. It is difficult to obtain a polymerized toner having poor characteristics and practical performance.

  On the other hand, the poorly water-soluble inorganic compounds include calcium phosphate, barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, magnesium carbonate and other poorly water-soluble salts; inorganic polymer substances such as talc and silicic acid; aluminum oxide, titanium oxide Metal oxides such as aluminum hydroxide, metal hydroxides such as ferric hydroxide, and the like are known. These poorly water-soluble inorganic compounds exhibit a function as a dispersant when present as fine particles such as colloid in an aqueous medium. The slightly water-soluble inorganic compound fine particles can be solubilized and removed by acid washing after the polymerization or alkali washing after the polymerization depending on the respective characteristics.

  Conventionally, as a method for producing a polymerized toner that suppresses the generation of fine particles and coarse particles and has a high yield and a sharp particle size distribution, attention is paid to an aqueous medium containing finely water-insoluble inorganic compound fine particles as a dispersant. Several methods with improvements to the preparation process have been proposed.

For example, in the step of preparing an aqueous medium containing calcium phosphate as a dispersant, a calcium ion-containing aqueous solution is added to a phosphate ion-containing aqueous solution to form a calcium phosphate salt. A method has been proposed in which the rate of addition is controlled so that the ratio of the number of moles of calcium ions to the number of moles of phosphate ions in the phosphate ion-containing aqueous solution is 0.005 to 0.5 s ^−1. (For example, refer to Patent Document 1).

  In addition, by using an aqueous medium containing a colloid of a hardly water-soluble metal hydroxide salt produced by a reaction between a water-soluble polyvalent metal salt and an alkali metal hydroxide metal salt in an aqueous phase, Has been proposed for producing a polymerized toner having a particle size distribution of 1.6 or less (see, for example, Patent Document 2).

  Thus, conventionally, when preparing an aqueous medium containing a hardly water-soluble inorganic compound fine particle as a dispersant, generally two kinds of water-soluble inorganic compounds are reacted in an aqueous phase to form a hardly water-soluble inorganic compound fine particle. However, in general, any inorganic compound is mixed and reacted in the form of an aqueous solution.

  However, according to the examination results of the present inventors, the preparation methods of the dispersants disclosed in these documents all have a desired small particle size and a sharp particle size distribution, and the amount of fine powder produced is small. It has been found that this is not yet a sufficient method for obtaining extremely small polymerized toner.

JP 11-119465 A JP-A-6-332257

  An object of the present invention is to provide an efficient method for producing a polymerized toner having a very sharp particle size distribution and an extremely small amount of fine powder.

  In particular, the object of the present invention is to form a droplet having a small particle size and a sharp particle size distribution in an aqueous medium in the droplet forming step of the polymerizable monomer composition even if a relatively small amount of a dispersant is used. Further, the present invention provides a new production method capable of obtaining colored polymer particles having a desired particle size and a sharp particle size distribution by a subsequent polymerization step.

  As a result of intensive studies to achieve the above object, the present inventor has obtained an aqueous medium containing, as a dispersant, slightly water-soluble inorganic compound fine particles formed by reaction of two types of water-soluble inorganic compounds in an aqueous phase. In the step of preparing, the water-soluble inorganic compound fine particles are formed by bringing an aqueous solution of one of the two types of water-soluble inorganic compounds into contact with a solid of the other inorganic compound to cause a reaction. I came up with a method.

  Conventionally, in preparing an aqueous medium containing finely water-insoluble inorganic compound fine particles as a dispersant, a method of mixing and reacting two aqueous solutions of two types of water-soluble inorganic compounds has been generally employed. Surprisingly, one of two kinds of inorganic compounds capable of forming slightly water-soluble inorganic compound fine particles by reaction in the aqueous phase is an aqueous solution, the other is a solid, and both are subjected to a solid-liquid reaction. When polymerization is performed using the obtained aqueous medium containing the hardly water-soluble inorganic compound fine particles, the aqueous medium containing the hardly water-soluble inorganic compound fine particles obtained by reacting aqueous solutions of two kinds of inorganic compounds is used. It was found that the amount of fine powder produced was remarkably suppressed and colored polymer particles having an extremely sharp particle size distribution were obtained as compared with the case of the above. The present invention has been completed based on these findings.

  Thus, according to the present invention, at least the polymerizable monomer and the water-soluble inorganic compound fine particles formed by the reaction in the aqueous phase of two kinds of water-soluble inorganic compounds are contained in the aqueous medium containing the dispersant. In a method for producing a polymerized toner comprising a step of dispersing a polymerizable monomer composition containing a colorant into droplets and then polymerizing to form colored polymer particles, the slightly water-soluble inorganic compound fine particles include: Production of a polymerized toner characterized in that it is formed by bringing an aqueous solution of one of the two types of water-soluble inorganic compounds into contact with a solid of the other inorganic compound to cause a reaction. A method is provided.

  According to the present invention, there is provided a method for efficiently producing a polymerized toner having a very sharp particle size distribution and an extremely small amount of fine powder. In particular, according to the present invention, the polymerization method can be used to design a desired average particle size even when the particle size distribution is very sharp, the amount of fine powder is extremely small, and the volume average particle size is as small as 4 to 9 μm. A method for producing a polymerized toner is provided.

1. Preparation of slightly water-soluble inorganic compound fine particles :
As a dispersant used for producing a polymerized toner by suspension polymerization in an aqueous medium, fine particles of a poorly water-soluble inorganic compound, particularly a colloid is suitable. Examples of poorly water-soluble inorganic compounds include inorganic salts such as barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, magnesium carbonate, and calcium phosphate; inorganic oxides such as aluminum oxide and titanium oxide; aluminum hydroxide, magnesium hydroxide, And inorganic hydroxide of ferric hydroxide. Since many of these poorly water-soluble inorganic compounds are metal compounds, they may be referred to as poorly water-soluble metal compounds.

  Among the fine particles of the hardly water-soluble inorganic compound, the hardly water-soluble inorganic hydroxide, particularly the colloid of the hardly water-soluble metal hydroxide, can narrow the particle size distribution of the colored polymer particles, and the sharpness of the image is improved. Since it improves, it is suitable. Inorganic salts such as calcium phosphate are also preferred as the dispersant.

  The dispersant used in the present invention is slightly water-soluble inorganic compound fine particles formed by reaction of two types of water-soluble inorganic compounds in the aqueous phase. In the present invention, the slightly water-soluble inorganic compound fine particles are formed by bringing an aqueous solution of one of the two types of water-soluble inorganic compounds into contact with a solid of the other inorganic compound to cause a reaction. In the present invention, the slightly water-soluble inorganic compound fine particle forming step is a forming step by reaction in the aqueous phase in order to react the solid matter of the other inorganic compound in the aqueous solution of one inorganic compound. It can also be called the formation process by reaction.

  Thus, in the present invention, the hardly water-soluble inorganic compound fine particles are formed by the reaction in the aqueous phase of the solid (solid matter) and the liquid (aqueous solution). The aqueous solution containing the poorly water-soluble inorganic compound fine particles thus obtained is used as an aqueous medium. By forming and polymerizing droplets of the polymerizable monomer composition in the aqueous medium, the amount of fine particles and coarse particles generated is remarkably small, and a high yield of a polymer toner having a very sharp particle size distribution is obtained. Can be obtained at

  As the two types of water-soluble inorganic compounds, a combination of a water-soluble polyvalent inorganic compound and an alkali metal hydroxide is preferable. As the water-soluble polyvalent inorganic compound, a water-soluble polyvalent metal compound is usually used, and a water-soluble polyvalent metal salt is preferably used.

  Examples of water-soluble polyvalent metal salts used as water-soluble polyvalent inorganic compounds include hydrochlorides, sulfates, nitrates, and acetates of polyvalent metals such as magnesium, calcium, aluminum, iron, copper, manganese, nickel, and tin. Is mentioned. Among these, magnesium, calcium, and aluminum salts are preferable. On the other hand, examples of the alkali metal hydroxide salt include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide. Either one of a water-soluble polyvalent metal salt and an alkali metal hydroxide is used in the form of an aqueous solution, and the other is used as a solid.

  Examples of the two types of water-soluble inorganic compounds include phosphoric acid or a combination of a water-soluble phosphate and a water-soluble calcium salt. A typical example of the phosphate is sodium phosphate. A typical calcium salt is calcium chloride. By reacting phosphoric acid or a water-soluble phosphate with a water-soluble calcium salt, poorly water-soluble calcium phosphate is produced. Either phosphate or calcium salt is used as an aqueous solution, and the other is used as a solid.

  As a method of bringing the aqueous solution of one inorganic compound into contact with the solid matter of the other inorganic compound, a method of adding a solid matter to the aqueous solution is usually preferably employed. The magnitude | size (average particle diameter or average diameter) of a solid substance is 0.01-3 mm normally, Preferably it is 0.05-2 mm, More preferably, it is the range of 0.1-1 mm. The shape of the solid is particulate, but the specific shape may be any of a spherical shape, an indeterminate shape, a flat shape, a pellet, and the like.

  Compared to the case where the aqueous solution of one inorganic compound of the two types of water-soluble inorganic compound is added to the aqueous solution of the other inorganic compound to mix and react with each other, the surface of the solid material in the aqueous solution It is considered that fine particles of a slightly water-soluble inorganic compound having a uniform size are formed. When the size of the solid is less than 0.01 mm, the handleability of the solid is poor and the productivity is lowered. If the average particle size of the solid is too small, it dissolves immediately in the aqueous solution of the other inorganic compound, so that the difference in performance from the case of using the aqueous solution is reduced. When the size of the solid material exceeds 3 mm, the surface area of the solid-liquid interface decreases and the reaction point decreases, so that it becomes difficult to form fine particles of a hardly water-soluble inorganic compound having a uniform particle size distribution. As a result, the finally obtained polymerized toner also has a large volume average particle size and a broad particle size distribution.

  The chemical equivalent ratio of the two types of water-soluble inorganic compounds is not particularly limited as long as it is within a range in which desired slightly water-soluble inorganic compound fine particles are generated by the reaction of both. As a specific example, the chemical equivalent ratio (b / a) of the alkali hydroxide metal salt (chemical equivalent b) to the water-soluble polyvalent metal salt (chemical equivalent a) is preferably 0.4 to 1.0. Preferably it is the range of 0.6-0.8.

  As the hardly water-soluble inorganic compound fine particles, a colloid of a hardly water-soluble inorganic hydroxide obtained by bringing an aqueous solution of a water-soluble polyvalent inorganic compound and a solid of an alkali metal hydroxide salt into contact with each other is preferable, More preferably, it is a colloid of magnesium hydroxide salt obtained by bringing an aqueous solution of magnesium chloride into contact with a solid substance of sodium hydroxide for reaction. As a method for forming such a colloid, a method in which a granular alkali metal hydroxide salt is continuously added to and reacted with an aqueous solution of a water-soluble polyvalent inorganic compound is preferable.

  A dispersing agent is normally used in the ratio of 0.1-20 weight part with respect to 100 weight part of polymerizable monomers. If this ratio is too small, the stability of the droplets of the polymerizable monomer composition is lowered, it becomes difficult to obtain sufficient polymerization stability, and polymerized aggregates are easily formed. When the proportion of the dispersant is too large, the viscosity of the aqueous medium increases, it becomes difficult to form droplets, and the polymerization stability also decreases. The concentration of the total dispersoid in the aqueous medium, that is, the weight ratio of the total dispersoid to the total weight of the total dispersoid and the aqueous medium is usually 5 to 50% by weight, preferably 10 to 30% by weight. . Therefore, the concentration of the aqueous solution of the inorganic compound is adjusted so that the ratio of the hardly water-soluble inorganic compound fine particles to be produced and the concentration of the dispersoid are within the above ranges, or an aqueous medium is added as necessary after the reaction.

2. Raw material for polymerized toner :
The polymerized toner is colored polymer particles in which a polymer formed by polymerization of a polymerizable monomer becomes a binder resin, and additive components such as a colorant, a charge control agent, and a release agent are dispersed therein. The method for producing a polymerized toner of the present invention comprises a step of forming a polymerizable monomer composition containing at least a polymerizable monomer and a colorant into fine droplets in an aqueous medium containing a dispersant. And a step of polymerizing the polymerizable monomer composition after the droplet formation. After the polymerization step, a washing step, a drying step and the like of the produced colored polymer particles are arranged.

  In the polymerization step, the polymerizable monomer composition is polymerized in an aqueous medium to produce colored polymer particles. If desired, the shell polymerizable monomer is further polymerized in the presence of the colored polymer particles. In addition, a core / shell type colored polymer particle may be generated by adding the step of the step. As the aqueous medium, water such as ion-exchanged water is used, but a hydrophilic solvent such as alcohol may be added if desired. The aqueous medium contains a dispersant to improve the dispersion stability of the polymerizable monomer composition droplets. In general, the aqueous medium is also used as a dispersion medium in the droplet forming step. In the present invention, an aqueous medium containing the hardly water-soluble inorganic compound fine particles produced by the above-described method is used as the aqueous medium containing the dispersant.

  In the polymerizable monomer composition, in addition to the polymerizable monomer and the colorant, if necessary, a charge control agent, a release agent, a crosslinkable monomer, a macromonomer, a molecular weight adjusting agent, a lubricant, Various additives such as a dispersion aid can be contained. Among these additives, it is preferable to contain a charge control agent and a release agent.

(1) Polymerizable monomer:
In the present invention, a monovinyl monomer is used as the main component of the polymerizable monomer. Examples of the monovinyl monomer include aromatic vinyl monomers such as styrene, vinyltoluene, and α-methylstyrene; (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Such as propyl acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, (meth) acrylamide, etc. Derivatives of (meth) acrylic acid; monoolefin monomers such as ethylene, propylene and butylene;

  Monovinyl monomers may be used alone or in combination of a plurality of monomers. Of these monovinyl monomers, aromatic vinyl monomers alone, combinations of aromatic vinyl monomers and (meth) acrylic acid derivatives, and the like are preferably used.

  When a crosslinkable monomer is used together with a monovinyl monomer, the hot offset property can be improved. A crosslinkable monomer is a monomer having two or more vinyl groups. Specific examples thereof include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; diethylenically unsaturated carboxylic acid esters such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and 1,4-butanediol diacrylate; Examples thereof include compounds having two vinyl groups such as N, N-divinylaniline and divinyl ether, and compounds having three or more vinyl groups such as pentaerythritol triallyl ether and trimethylolpropane triacrylate.

  These crosslinkable monomers can be used alone or in combination of two or more. The amount used is usually 10 parts by weight or less, preferably 0.01 to 7 parts by weight, more preferably 0.05 to 5 parts by weight, particularly preferably 0.1 to 100 parts by weight of the monovinyl monomer. 3 parts by weight.

  It is preferable to use a macromonomer together with a monovinyl monomer because the balance between storage stability at high temperature and fixability at low temperature is improved. The macromonomer is a macromolecule having a polymerizable carbon-carbon unsaturated double bond at the end of the molecular chain, and is an oligomer or polymer having a number average molecular weight of usually 1,000 to 30,000. When the number average molecular weight is within the above range, it is preferable because the fixability and storability of the polymerized toner can be maintained without impairing the meltability of the macromonomer.

  Examples of the polymerizable carbon-carbon unsaturated double bond at the molecular chain terminal of the macromonomer include an acryloyl group and a methacryloyl group, and a methacryloyl group is preferred from the viewpoint of ease of copolymerization. The macromonomer is preferably one that gives a polymer having a glass transition temperature higher than that of a polymer obtained by polymerizing a monovinyl monomer.

  Specific examples of macromonomers include polymers obtained by polymerizing styrene, styrene derivatives, methacrylic acid esters, acrylic acid esters, acrylonitrile, methacrylonitrile, etc. alone or in combination of two or more; macromonomers having a polysiloxane skeleton Among these, a hydrophilic one is preferable, and a polymer obtained by polymerizing methacrylic acid ester or acrylic acid ester alone or in combination thereof is particularly preferable.

  When the macromonomer is used, the amount used is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.05 to 1 part per 100 parts by weight of the monovinyl monomer. Parts by weight. When the amount of the macromonomer is within the above range, it is preferable because the preservability of the polymerized toner is maintained and the fixing property is improved.

(2) Colorant:
As the colorant, various pigments and dyes used in the field of toner such as carbon black and titanium white can be used. Examples of the black colorant include carbon black and nigrosine-based dyes and pigments; magnetic particles such as cobalt, nickel, iron tetroxide, manganese iron oxide, zinc iron oxide, and nickel iron oxide. When carbon black is used, it is preferable to use carbon black having a primary particle size of 20 to 40 nm because good image quality can be obtained and the safety of the toner to the environment is enhanced. As a color toner colorant, a yellow colorant, a magenta colorant, a cyan colorant, or the like can be used.

  As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds, and the like are used. Specifically, for example, C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 90, 93, 95, 96, 97, 109, 110, 111, 120, 128, 129, 138, 147, 155, 168, 180, 181 and the like. In addition, Nephthol Yellow S, Hansa Yellow G, C.I. I. Examples thereof include bat yellow.

  Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, for example, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 31, 48, 48: 2, 48: 3, 48: 4, 57, 57: 1, 58, 60, 63, 64, 68, 81, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 166, 169, 170, 177, 184, 185, 187, 202, 206, 207, 209, 220, 251, 254 and the like. In addition, C.I. I. Pigment violet 19 and the like.

  Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like. Specifically, for example, C.I. I. Pigment Blue 1, 2, 3, 6, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17, 60, 62, 66, and the like. In addition, phthalocyanine blue, C.I. I. Bat Blue, C.I. I. Acid blue and so on.

  These colorants can be used alone or in combination of two or more. The colorant is usually used in a proportion of 0.1 to 50 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of the polymerizable monomer.

(3) Charge control agent:
In order to improve the chargeability of the polymerized toner, it is preferable to include various positively chargeable or negatively chargeable charge control agents in the polymerizable monomer composition. Examples of the charge control agent include metal complexes of organic compounds having a carboxyl group or a nitrogen-containing group, metal-containing dyes, nigrosine, charge control resins, and the like.

  Specifically, Bontron N-01 (manufactured by Orient Chemical Co., Ltd.), Nigrosine Base EX (manufactured by Orient Chemical Co., Ltd.), Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.), T-77 (manufactured by Hodogaya Chemical Co., Ltd.) Bontron S-34 (made by Orient Chemical Industries), Bontron E-81 (made by Orient Chemical Industries), Bontron E-84 (made by Orient Chemical Industries), Bontron E-89 (made by Orient Chemical Industries), Bontron F-21 (manufactured by Orient Chemical Co., Ltd.), COPY CHARGE NX VP434 (manufactured by Clariant), COPY CHARGE NEG VP2036 (manufactured by Clariant), LR-147 (manufactured by Nippon Carlit), copy blue PR (manufactured by Clariant), etc. Charge control agent; quaternary ammonium (salt) group-containing copolymer , Charge control resins such as sulfonic acid (salt) group-containing copolymers; and the like can be given. The charge control agent is usually used in a proportion of 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

(4) Release agent:
A release agent can be included in the polymerizable monomer composition for the purpose of preventing offset or improving the releasability at the time of hot roll fixing. Examples of the release agent include polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; plant-based natural waxes such as candelilla, carnauba, rice, wood wax, jojoba; paraffin, microcrystalline, petrolactam, and the like. Petroleum waxes and modified waxes thereof; synthetic waxes such as Fischer-Tropsch wax; polyfunctional ester compounds such as pentaerythritol tetramyristate, pentaerythritol tetrapalmitate, dipentaerythritol hexamyristate; and the like. These release agents can be used alone or in combination of two or more.

  Among these release agents, synthetic waxes, terminal-modified polyolefin waxes, petroleum waxes, and polyfunctional ester compounds are preferable. The ratio of the release agent used is usually 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

(5) Polymerization initiator:
Examples of the polymerization initiator for the polymerizable monomer include persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis [2-methyl -N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'- Azo compounds such as azobisisobutyronitrile and 2,2'-azobis (2-methylpropionate); di-t-butyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl Peroxy-2-ethylhexanoate, t-hexyl peroxy-2-ethylhexanoate, t-butyl peroxypivalate, di-isopropyl pero Peroxides such as sidicarbonate, di-t-butylperoxyisophthalate, 1,1 ', 3,3'-tetramethylbutylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate And the like. A redox initiator in which these polymerization initiators and a reducing agent are combined can also be used.

  Among these initiators, it is preferable to select an oil-soluble polymerization initiator that is soluble in the polymerizable monomer, and a water-soluble polymerization initiator can be used in combination as necessary. The polymerization initiator is usually used in a proportion of 0.1 to 20 parts by weight, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer. It is done.

  The polymerization initiator can be added in advance to the polymerizable monomer composition, but in order to suppress premature polymerization, after completion of the droplet forming step of the polymerizable monomer composition or during the polymerization reaction It can also be added directly to the suspension.

(6) Molecular weight regulator:
In the polymerization, a molecular weight modifier is preferably used. Examples of the molecular weight modifier include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, 2,2,4,6,6-pentamethylheptane-4-thiol; carbon tetrachloride, four And halogenated hydrocarbons such as carbon bromide; The molecular weight modifier is usually contained in the polymerizable monomer composition before the start of polymerization, but can also be added during the polymerization. The molecular weight modifier is usually used in a proportion of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, with respect to 100 parts by weight of the polymerizable monomer.

3. Droplet formation process :
In order to produce a polymerized toner, a polymerizable monomer, a colorant, and other additives are mixed using a mixer, and if necessary, a media-type wet pulverizer (for example, a bead mill) is used. And wet pulverizing to prepare a polymerizable monomer composition. Next, the polymerizable monomer composition is dispersed in an aqueous medium containing a dispersant and stirred to form uniform droplets of the polymerizable monomer composition (volume average particle diameter is about 50 to 1000 μm). Primary droplets) are preliminarily formed. In order to avoid premature polymerization, the polymerization initiator is preferably added to the aqueous medium after the size of the droplets becomes uniform in the aqueous medium.

  When using a color toner pigment as a colorant and a charge control resin as a charge control agent, a pigment master batch is prepared by kneading the pigment and the charge control resin in advance. It is preferable to make it contain in a monomer composition.

  A polymerization initiator is added to and mixed with a dispersion liquid in which droplets of the polymerizable monomer composition are dispersed in an aqueous medium. Stir until small particle size close to toner particles.

  The volume average particle size and particle size distribution of the fine droplets of the polymerizable monomer composition affect the volume average particle size and particle size distribution of the colored polymer particles (polymerized toner). When the particle size of the droplet is too large, the average particle size of the colored polymer particles to be generated becomes too large, and the resolution of the image is lowered. When the particle size distribution of the droplets is wide, the particle size distribution of the colored polymer particles to be generated becomes wide, causing a variation in fixing temperature, causing problems such as fogging and toner filming. Therefore, it is desirable to form the droplets of the polymerizable monomer composition so as to be approximately the same size as the colored polymer particles.

  In the present invention, the volume average particle diameter of the droplets of the polymerizable monomer composition is a particle diameter Dv50 in which the cumulative volume calculated from the small particle diameter side of the droplets of the polymerizable monomer composition is 50%. (Μm) is used. The particle size Dv50 of the droplets (hereinafter sometimes simply referred to as “droplet particle size Dv”) can be measured using, for example, a SALD particle size distribution analyzer (manufactured by Shimadzu Corporation).

  The droplet diameter Dv of the polymerizable monomer composition is preferably 3 to 10 μm, more preferably 4 to 9 μm, and particularly preferably 4 to 8 μm. In order to obtain a high-definition image, it is effective to use a polymer toner having a small particle diameter. To that end, it is desirable to reduce the droplet diameter Dv. The particle size distribution (volume average particle size / number average particle size) of the droplets of the polymerizable monomer composition is preferably 1 to 2, more preferably 1 to 1.5.

  As a method of controlling the droplet diameter Dv of the polymerizable monomer composition, a method of adjusting the amount of a dispersion stabilizer such as a hardly water-soluble metal hydroxide colloid is generally employed. However, the droplet diameter Dv varies depending on the stirring condition of the dispersion. Accordingly, the droplet size Dv can be precisely controlled by first adjusting the amount of the dispersant used and controlling the stirring conditions so that a substantially desired droplet size Dv can be obtained. preferable.

4). Polymerization process :
A dispersion containing fine droplets formed by the above method is charged into a polymerization reactor, and suspension polymerization is usually performed at a temperature of 5 to 120 ° C, preferably 35 to 95 ° C. If the polymerization temperature is too low, a polymerization initiator having a high catalytic activity must be used, which makes it difficult to manage the polymerization reaction. If the polymerization temperature is too high, when an additive that melts at a low temperature is included, this may bleed on the surface of the polymerized toner, resulting in poor storage stability.

  One or more of the above-mentioned monovinyl monomers are selected as the polymerizable monomer. To lower the toner fixing temperature, the glass transition temperature Tg is usually 80 ° C. or lower, preferably 40 to 80 ° C. Preferably, a polymerizable monomer or a combination of polymerizable monomers capable of forming a polymer at 50 to 70 ° C. is selected. In the present invention, the Tg of the copolymer constituting the binder resin is a calculated value (referred to as “calculated Tg”) calculated according to the type and use ratio of the polymerizable monomer to be used.

  By the polymerization, colored polymer particles in which an additive component such as a colorant is dispersed in the polymer of the polymerizable monomer are generated. In the present invention, the colored polymer particles can be used as a polymerized toner, but are obtained by polymerization for the purpose of improving the storage stability (blocking resistance), low-temperature fixability, meltability at the time of fixing, and the like of the polymerized toner. A polymer layer can be further formed on the colored polymer particles thus obtained, whereby a capsule toner having a core / shell structure can be obtained.

  As a method for forming the core-shell structure, the above colored polymer particles are used as core particles, and the polymerizable monomer for shell is further polymerized in the presence of the core particles, and a polymer layer ( Shell) is employed. When a monomer that forms a polymer having a Tg higher than that of the polymer component constituting the core particle is used as the polymerizable monomer for the shell, the storage stability of the polymerized toner can be improved. On the other hand, by setting the Tg of the polymer component constituting the core particle low, the fixing temperature of the polymerized toner can be lowered or the melting characteristics can be improved. Therefore, by forming the core-shell type polymer particles in the polymerization step, a polymerized toner that can cope with high speed printing (copying, printing, etc.), full color, OHP (overhead projector) permeability, and the like can be obtained.

  As the polymerizable monomer for forming the core and the shell, a preferable monomer can be appropriately selected from the monovinyl monomers described above. The weight ratio of the polymerizable monomer for the core and the polymerizable monomer for the shell is usually 40/60 to 99.9 / 0.1, preferably 60/40 to 99.7 / 0.3, more preferably Is 80 / 20-99.5 / 0.5. If the ratio of the polymerizable monomer for the shell is too small, the effect of improving the storage stability of the polymerized toner is small, and if it is excessive, the effect of reducing the fixing temperature is small.

  The Tg of the polymer formed by the polymerizable monomer for shell is usually more than 50 ° C. and 120 ° C. or less, preferably more than 60 ° C. and less than 110 ° C., more preferably more than 80 ° C. and less than 105 ° C. The difference in Tg between the polymer formed from the core polymerizable monomer and the polymer formed from the shell polymerizable monomer is preferably 10 ° C. or higher, more preferably 20 ° C. or higher, particularly Preferably it is 30 degreeC or more. In many cases, from the viewpoint of the balance between the fixing temperature and the storage stability, a core polymerizable monomer that can form a polymer having a Tg of usually 60 ° C. or lower, preferably 40 to 60 ° C. is selected. Is preferred. On the other hand, as the polymerizable monomer for the shell, it is preferable to use a monomer that forms a polymer having a Tg of more than 80 ° C. such as styrene or methyl methacrylate, either alone or in combination of two or more. .

  A charge control agent can be added to the polymerizable monomer for shell. The charge control agent is preferably the same as that used in the core particle production described above. When used, the charge control agent is usually 0.01 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer for shell. , Preferably 0.1 to 5 parts by weight.

  When adding the shell polymerizable monomer, it is preferable to add a water-soluble radical initiator in order to efficiently form the shell. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis- Examples thereof include azo initiators such as [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide]. The amount of the water-soluble polymerization initiator used is usually 0.1 to 50% by weight, preferably 1 to 20% by weight, per 100 parts by weight of the shell polymerizable monomer.

  The average thickness of the shell is usually 0.001 to 1.0 μm, preferably 0.003 to 0.5 μm, and more preferably 0.005 to 0.2 μm. When the shell thickness is too large, the fixing property of the polymerized toner is lowered, and when it is too small, the storage property of the polymerized toner is lowered. When the core particle diameter and shell thickness of the polymerized toner can be observed with an electron microscope, it can be obtained by directly measuring the particle size and shell thickness randomly selected from the observation photograph. When it is difficult to observe the core and the shell, it can be calculated from the particle size of the core particle and the amount of the polymerizable monomer that forms the shell.

5). Collection process :
An aqueous medium (dispersion) containing colored polymer particles (including core / shell type colored polymer particles) is obtained by the polymerization step. In the recovery process, filtration, washing, drying, and the like are sequentially performed.

  In the filtration / washing step, use the dispersion obtained in the polymerization step as it is, or add ion exchange water to adjust the concentration of the colored polymer particles, and the dispersion containing the colored polymer particles And At this stage, in order to solubilize and remove the slightly water-soluble inorganic compound fine particles of the used dispersant, treatment such as acid cleaning or alkali cleaning is performed according to the type of the dispersant. For example, when a colloid of a poorly water-soluble metal hydroxide such as magnesium hydroxide is used as a dispersant, generally an acid such as dilute sulfuric acid is added to acidify the pH of the dispersion, Dissolve in aqueous medium. Further, the monomer removal treatment may be performed by stripping or the like in the state of the dispersion.

  The method of filtration and washing is not particularly limited, and is arbitrary, for example, a method of performing filtration and washing of the colored polymer particle cake using a vacuum belt filter. After the washing step, wet colored polymer particles (wet cake) are recovered. The collection of the colored polymer particles is performed by a drying process according to a conventional method, and the dried colored polymer particles are collected.

  The volume average particle diameter (dv) of the polymerized toner (including core / shell capsule toner) obtained by the production method of the present invention is not particularly limited, but is usually 3 to 10 μm, preferably 4 to 9 μm, more preferably 4-8 μm. When obtaining a high-definition image by increasing the resolution, it is preferable that the volume average particle diameter of the toner is such a small particle diameter.

  The particle size distribution expressed by volume average particle size (dv) / number average particle size (dp) of the polymerized toner of the present invention is usually less than 1.25, preferably 1.20 or less, particularly preferably 1.15 or less. It is. If the volume average particle size of the polymerized toner is too large, the resolution tends to decrease. If the particle size distribution of the polymerized toner is large, the proportion of toner having a large particle size increases, and the resolution tends to decrease.

  The amount of fine powder in the polymerized toner of the present invention is reduced. More specifically, the polymerized toner of the present invention preferably has a number distribution with a volume average particle diameter dv of 3 μm or less, preferably 10% or less, more preferably 8% or less, still more preferably 7% or less, particularly preferably 6% or less. Even though the volume average particle size is small, the amount of fine powder is remarkably reduced.

  The polymerized toner of the present invention has a volume average particle diameter dv of 4 to 9 μm, a ratio dv / dp of the volume average particle diameter dv to the number average particle diameter dp of less than 1.25, and a volume average particle diameter dv of 3 μm or less. The number distribution is preferably 8% or less.

  In the polymerized toner of the present invention, the sphericity represented by the ratio (dl / ds) of the major axis (dl) to the minor axis (ds) is preferably 1 to 1.3, more preferably 1 to 1.2. It is preferably substantially spherical. When substantially spherical polymerized toner is used as the non-magnetic one-component developer, the transfer efficiency of the toner image on the photoreceptor to the transfer material is improved.

  The polymerized toner of the present invention can be used as a toner component of various developers, but is preferably used as a nonmagnetic one-component developer. When the polymerized toner of the present invention is a non-magnetic one-component developer, an external additive can be mixed as necessary. Examples of the external additive include inorganic particles and organic resin particles that act as a fluidizing agent and an abrasive.

  Examples of the inorganic particles include silicon dioxide (silica), aluminum oxide (alumina), titanium oxide, zinc oxide, tin oxide, barium titanate, and strontium titanate. As organic resin particles, methacrylic acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, styrene-acrylic acid ester copolymer particles, a core is a styrene polymer, and a shell is methacrylic acid. Examples thereof include core / shell type particles formed of an ester copolymer.

  Among these, inorganic oxide particles are preferable, and silicon dioxide is particularly preferable. The surface of the inorganic fine particles can be hydrophobized, and silicon dioxide particles that have been hydrophobized are particularly suitable. Two or more types of external additives may be used in combination. In the case of using a combination of external additives, a method of combining inorganic particles having different average particle sizes or a combination of inorganic particles and organic resin particles is preferable. . The amount of the external additive is not particularly limited, but is usually 0.1 to 6 parts by weight with respect to 100 parts by weight of the polymerized toner. In order to attach the external additive to the polymerized toner, the polymerized toner and the external additive are usually placed in a mixer such as a Henschel mixer and stirred.

  The polymerized toner of the present invention has excellent print density and remarkably little fogging not only in a low temperature and low humidity environment but also in a high temperature and high humidity environment. Further, the polymerized toner of the present invention has excellent resolution and excellent cleaning properties.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following Examples and Comparative Examples, “parts” and “%” are based on weight unless otherwise specified. The evaluation method is as follows.

(1) Volume average particle size and particle size distribution:
The volume average particle diameter dv of the colored polymer particles (polymerized toner) and the particle size distribution, that is, the ratio dv / dp of the volume average particle diameter dv to the number average particle diameter dp is the number% of particles of 3 μm or less (2 to 3 μm). , And the number% of particles of 5 μm or less (2 to 5 μm) were measured by Multisizer (manufactured by Beckman Coulter). The measurement with this multisizer was carried out under the conditions of aperture diameter = 100 μm, medium = Isoton II, concentration = 10%, and number of measured particles = 100,000.

(2) Print density:
Set the copy paper in a commercially available non-magnetic one-component developing type printer (trade name “Microline 3010C” manufactured by Oki Data Co., Ltd.), put toner (non-magnetic one-component developer) in the developing device, and set the temperature at 10 ° C. / The samples were left overnight in a low temperature / low humidity (L / L) environment with a relative humidity of 20% and under a high temperature / high humidity (H / H) environment with a temperature of 35 ° C./80% relative humidity. Thereafter, continuous printing was performed from the beginning at 5% density in each environment. Solid printing was performed at the time of 20,000th continuous printing, and the print density of the printed surface was measured using a color reflection densitometer (manufactured by X-Light, model name “404A”).

(3) Fog:
Set the copy paper in a commercially available non-magnetic one-component developing type printer (trade name “Microline 3010C” manufactured by Oki Data Co., Ltd.), put toner (non-magnetic one-component developer) in the developing device, and set the temperature at 10 ° C. / The samples were left overnight in an L / L environment with a relative humidity of 20% and in an H / H environment with a temperature of 35 ° C./80% relative humidity. Thereafter, continuous printing was performed from the beginning at 5% density in each environment. After the 20,000th continuous printing, white solid printing is performed, printing is stopped halfway, and the toner in the non-image area on the developed photoconductor is adhesive tape (Scotch Mending Tape 810, manufactured by Sumitomo 3M Limited). It was peeled off at -3-18) and pasted on new copy paper. The color tone was measured using a spectroscopic color difference meter (manufactured by Nippon Denshoku Co., Ltd., trade name “SE-2000”), expressed as Lab space coordinates, and the color difference ΔE was calculated as the fog value. Smaller values indicate less fog.

(4) Cleanability:
Toner is put in the developing device of the printer described above, continuous printing is performed from the initial stage to 20,000 sheets, the photosensitive member and the charging roll are observed every 1,000 sheets, and the number of sheets where streaks due to poor cleaning occur is counted. .

(5) Resolution:
Using the printer described above, after continuous printing from the initial stage to 20,000 sheets, 1-dot line and 1-dot white line, and 2-dot line and 2-dot white line are printed. Was observed with an optical microscope and evaluated according to the following criteria.
A: A one-dot line and a one-dot white line are reproduced.
B: The 1-dot line and the 1-dot white line are not reproduced, but the 2-dot line and the 2-dot white line are reproduced.
C: 2 dot lines and 2 dot white lines are not reproduced.

[Example 1]
1. Colorant masterbatch preparation :
Charge control resin obtained by copolymerization of 82% styrene, 11% butyl acrylate, and 7% 2-acrylamido-2-methylpropanesulfonic acid (weight average molecular weight = 20,000, glass transition temperature Tg = 62 ° C. ) In 100 parts, 24 parts of methyl ethyl ketone and 6 parts of methanol were dispersed and kneaded with a roll while cooling. When the charge control resin is wound around the roll, 100 parts by weight of a magenta pigment (manufactured by Clariant, trade name “C.1. Pigment Red 122”) is gradually added and kneaded for 1 hour to obtain a charge control resin composition. (Colorant masterbatch) was produced. At this time, the roll gap is 1 mm in the initial stage, and then the gap is gradually widened and finally widened to 3 mm, and the organic solvent (methyl ethyl ketone / methanol = 4/1 mixed solvent) is adjusted according to the kneading state of the charge control resin. Added several times. The added organic solvent was removed under reduced pressure after mixing.

2. Preparation of polymerizable monomer composition for core :
Core consisting of 89 parts of styrene, 11 parts of n-butyl acrylate, 0.5 part of divinylbenzene and 0.25 part of polymethacrylate macromonomer (manufactured by Toa Gosei Chemical Co., Ltd., trade name “AA6”, Tg = 94 ° C.) Polymerizable monomer composition for core, 18 parts of the charge control resin composition, 2 parts of t-dodecyl mercaptan and 10 parts of dipentaerythritol hexamyristate are dispersed by a bead mill at room temperature. Got.

3. Preparation of aqueous medium :
To an aqueous solution in which 14.6 parts of magnesium chloride is dissolved in 265 parts of ion-exchanged water, 8.9 parts of solid sodium hydroxide having an average particle diameter of 0.6 mm is gradually added with stirring to obtain a magnesium hydroxide colloid. An aqueous medium containing (colloid of a hardly water-soluble inorganic hydroxide) was prepared. All aqueous media were prepared at room temperature.

4). Droplet formation process :
The polymerizable monomer composition was charged into the aqueous medium containing the magnesium hydroxide colloid obtained above at room temperature, and stirred until the droplets were stabilized. Thereafter, 5 parts of t-butyl peroxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name “Perbutyl O”) was added as a polymerization initiator, and then Ebara Milder (manufactured by Ebara Corporation) ) And high shear stirring at a rotational speed of 15,000 rpm for 20 minutes to form droplets of the polymerizable monomer composition.

5). Preparation of polymerizable monomer for shell :
2 parts of methyl methacrylate and 65 parts of ion exchange water were mixed to obtain an aqueous dispersion of a polymerizable monomer for shell.

6). Polymerization process :
1 part of sodium tetraborate decahydrate is added to the aqueous medium in which droplets of the polymerizable monomer composition for the core are formed, and the mixture is placed in a reactor equipped with a stirring blade and heated. The temperature was controlled to be constant at 90 ° C. After the polymerization conversion rate reached almost 100%, a water-soluble initiator (trade name “VA-086” = 2,2′-azobis, manufactured by Wako Pure Chemical Industries, Ltd.) was added to the aqueous dispersion of the polymerizable monomer for shell. A solution in which 0.2 part of [2-methyl-N (2-hydroxyethyl) -propionamide] was dissolved was added to the reactor, the polymerization reaction was continued for 4 hours, the reaction was stopped, and the core-shell type An aqueous dispersion containing colored polymer particles was obtained.

7). Post-processing process :
While stirring the aqueous dispersion of the colored polymer particles obtained above, sulfuric acid is added and the pH of the aqueous dispersion is adjusted to 4 or less, followed by acid washing, followed by separation of water by filtration, and a new ion exchange. 500 parts of water was added to reslurry and washed with water. Thereafter, again, dehydration and water washing were repeated several times. After washing, the solid content was separated by filtration. Colored polymer particles having a core-shell structure in which the solid content in the wet state is dried at 45 ° C. for two days and nights in a dryer, and the volume average particle size dv is 5.68 μm and the particle size distribution dv / dp is 1.13. Got.

8). Developer development :
Silica having a hydrophobicity of 65% and a volume average particle size of 12 nm (trade name “RX-200”, manufactured by Nippon Aerosil Co., Ltd.) as an external additive was added to 100 parts of the obtained core-shell colored polymer particles. 2.0 parts of silica having a hydrophobization degree of 64% and a volume average particle diameter of 40 nm (made by Nippon Aerosil Co., Ltd., trade name “RX-50”), and a cube shape having a volume average particle diameter of 0.3 μm Add 0.3 parts of calcium carbonate (manufactured by Maruo Calcium Co., Ltd., trade name “CUBE-03BHS”), mix with a Henschel mixer for 10 minutes at 1400 rpm, and use a non-magnetic one-component developer (toner) Was prepared. The results are shown in Table 1.

[Comparative Example 1]
In the step of preparing the aqueous medium containing magnesium hydroxide colloid, 10.3 parts of sodium hydroxide was added to 45 parts of ion-exchanged water under stirring in an aqueous solution in which 16.9 parts of magnesium chloride was dissolved in 215 parts of ion-exchanged water. Core-shell colored polymer particles were obtained in the same manner as in Example 1 except that the dissolved aqueous solution was gradually added to prepare an aqueous medium containing a magnesium hydroxide colloid. The obtained colored polymer particles had a volume average particle size dv of 5.79 μm and a particle size distribution dv / dp of 1.25. Table 1 shows the evaluation results of the obtained toner.

[Comparative Example 2]
In Comparative Example 1, a core / shell colored polymer was prepared in the same manner as in Comparative Example 1, except that 16.9 parts of magnesium chloride was changed to 14.6 parts and 10.3 parts of sodium hydroxide were changed to 8.9 parts. Particles were obtained. The obtained colored polymer particles had a volume average particle size dv of 6.25 μm and a particle size distribution dv / dp of 1.27. Table 1 shows the evaluation results of the obtained toner.

  The polymerized toner of the present invention is used to visualize an electrostatic latent image formed on a photosensitive member in an electrophotographic or electrostatic recording type copying machine, a laser beam printer, a facsimile, or the like. It can be used as a developer.

Claims (7)

  Polymerizability containing at least a polymerizable monomer and a colorant in an aqueous medium containing finely water-insoluble inorganic compound fine particles formed by reaction of two kinds of water-soluble inorganic compounds in an aqueous phase as a dispersant. In a method for producing a polymerized toner including a step of dispersing a monomer composition in droplets and then polymerizing to form colored polymer particles, the slightly water-soluble inorganic compound fine particles are formed of two kinds of water-soluble inorganic compounds. A method for producing a polymerized toner, which is formed by bringing an aqueous solution of one of the inorganic compounds into contact with a solid of the other inorganic compound to cause a reaction.   The production method according to claim 1, wherein the two types of water-soluble inorganic compounds are a water-soluble polyvalent inorganic compound and an alkali metal hydroxide.   The process according to claim 1, wherein the two types of water-soluble inorganic compounds are phosphoric acid or a water-soluble phosphate and a water-soluble calcium salt.   The manufacturing method according to claim 1, wherein the solid substance of the inorganic compound is a granular material having an average particle diameter of 0.01 to 3 mm.   The water-insoluble inorganic compound fine particle is a colloid of a water-insoluble inorganic hydroxide obtained by bringing an aqueous solution of a water-soluble polyvalent inorganic compound and a solid of an alkali metal hydroxide salt into contact with each other. 2. The production method according to 2.   6. The process according to claim 5, wherein the slightly water-soluble inorganic compound fine particles are a magnesium hydroxide salt colloid obtained by bringing an aqueous solution of magnesium chloride into contact with a solid substance of sodium hydroxide for reaction.   The production method according to claim 1, wherein the polymerizable monomer composition further contains a charge control agent and a release agent.