JP2005201985A - Toner and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which is easy to manufacture and uniform in particle diameter, suppresses moisture absorption at high temperature and high humidity, and also suppresses deterioration of properties due to moisture absorption. <P>SOLUTION: A method for manufacturing the toner includes a step of dispersing a metal salt of a fatty acid having a melting point of ≥80°C in an aqueous medium and a step of dispersing a polymerizable composition containing at least a vinyl-based monomer in the aqueous medium and carrying out polymerization. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner and a manufacturing method thereof, and more particularly to a toner used for developing an electrostatic latent image formed by an electrophotographic method, an electrostatic recording method, and the like, and a manufacturing method thereof.

  In the electrophotographic method and the electrostatic recording method, as a developer for visualizing an electrostatic latent image, a two-component developer composed of a toner and a carrier and a one-component developer substantially composed of a toner and not using a carrier The one-component developer includes magnetic one-component developer containing magnetic powder and non-magnetic one-component developer containing no magnetic powder.

  In a non-magnetic one-component developer, a fluidizing agent such as colloidal silica is often added independently in order to improve the fluidity of the toner. As the toner, generally, colored particles obtained by dispersing a colorant such as carbon black and other additives in a binder resin are used.

  The toner production methods are roughly classified into a pulverization method and a polymerization method. In the pulverization method, a synthetic resin, a colorant, and other additives as necessary are melt-mixed and then pulverized and classified so as to obtain particles having a desired particle diameter, thereby obtaining a toner.

  In the polymerization method, a polymerizable composition in which a colorant, a polymerization initiator, and various additives such as a crosslinking agent and a charge control agent are uniformly dissolved or dispersed in a polymerizable monomer is prepared and dispersed. A toner having a desired particle diameter is obtained by dispersing in a water-based dispersion medium containing a stabilizer using a stirrer to form fine droplets of the polymerizable composition, followed by suspension polymerization at elevated temperature. ing.

  In any developer, the electrostatic latent image is substantially developed with toner. In general, in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, an electrostatic latent image is formed on a uniformly charged photoreceptor to form an electrostatic latent image, and toner is attached to the electrostatic latent image. The toner image (visible image) is transferred to a transfer material such as transfer paper, and the unfixed toner image is fixed on the transfer material by various methods such as heating, pressurization, and solvent vapor. I am letting.

  In the fixing step, in many cases, a transfer material onto which a toner image is transferred is passed between a heating roll (fixing roll) and a pressure roll, and the toner is heat-pressed and fused onto the transfer material.

  An image formed by an image forming apparatus such as an electrophotographic copying machine is required to be improved in definition year by year. Conventionally, toner obtained by a pulverization method has been mainstream as toner used in an image forming apparatus.

  According to the pulverization method, colored particles having a wide particle size distribution are easily formed, and in order to obtain satisfactory development characteristics, it is necessary to classify the pulverized product and adjust the particle size distribution to a certain degree. However, the classification itself is complicated, and the yield is poor, and the toner yield is greatly reduced.

Therefore, recently, a polymerized toner that is easy to control the particle size and does not need to go through complicated manufacturing processes such as classification has been attracting attention. According to the suspension polymerization method, a polymerized toner having a desired particle size and particle size distribution can be obtained without pulverization or classification (see, for example, Patent Document 1).
Japanese Patent Publication No. 51-14895

  An amorphous silicon drum is used as a photosensitive drum for an electrophotographic copying machine or the like. By using an amorphous silicon drum as the photosensitive drum, the life of the photosensitive drum can be extended, and the amount of waste substances can be reduced to reduce the influence on the environment.

  For an amorphous silicon drum, a positively charged toner is generally used. However, when a positively charged toner is produced by a suspension polymerization method, there are problems that granulation is difficult and that it is difficult for particles to exist stably at the stage of polymerization.

  For this reason, for example, a surfactant having a sulfonic acid group such as sodium dodecylbenzenesulfonate is added during the suspension polymerization method, but the surfactant remains on the toner surface after the polymerization is completed. Since the sulfonic acid group absorbs moisture and deteriorates the properties of the toner, there is a problem that the image is deteriorated during copying and printing.

  SUMMARY An advantage of some aspects of the invention is to provide a toner in which deterioration of characteristics due to moisture absorption is suppressed and a manufacturing method thereof.

  The method for producing a toner of the present invention includes a step of dispersing a fatty acid metal salt having a melting point of 80 ° C. or higher in an aqueous medium, and a step of dispersing and polymerizing a polymerizable composition containing at least a vinyl monomer in the aqueous medium. It is characterized by having.

  Another method for producing the toner of the present invention includes a step of mixing at least a vinyl monomer and a fatty acid metal salt having a melting point of 80 ° C. or higher to obtain a polymerizable composition, and dispersing the polymerizable composition in an aqueous medium. And a step of polymerizing.

  The toner of the present invention is a toner obtained by polymerizing at least a vinyl monomer, and is manufactured by the above-described toner manufacturing method.

  According to the present invention, by using a fatty acid metal salt having a melting point of 80 ° C. or higher in the production of toner, it is possible to suppress the moisture absorption of the toner under high temperature and high humidity, and to suppress the deterioration of characteristics due to this.

  Hereinafter, the method for producing the toner of the present invention will be described.

  The method for producing a toner of the present invention comprises a step of dispersing a fatty acid metal salt having a melting point of 80 ° C. or higher in an aqueous medium, and dispersing a polymerizable composition containing at least a vinyl monomer as a polymerizable monomer in the aqueous medium. And a step of polymerizing.

  Another method for producing the toner of the present invention includes a step of mixing at least a vinyl monomer as a polymerizable monomer and a fatty acid metal salt having a melting point of 80 ° C. or higher to obtain a polymerizable composition, and the polymerization in an aqueous medium. And a step of dispersing and polymerizing the composition.

  For the dispersion and polymerization of the polymerizable composition, for example, it is dispersed using a mixing device having a high shearing force and granulated into fine droplets, and then polymerized at a temperature of 30 to 200 ° C., preferably 50 to 100 ° C. By doing. The toner particles finally separated from the liquid phase are dried by a known method.

  In the present invention, a fatty acid metal salt having a melting point of 80 ° C. or higher is used in the dispersion and polymerization of the polymerizable composition as described above. By using such a fatty acid metal salt, it is easy to granulate droplets having a uniform particle size, and moisture absorption is suppressed even after the toner is formed, thereby preventing deterioration of characteristics. it can.

  That is, in the present invention, by using a fatty acid metal salt having a melting point of 80 ° C. or higher as described above without using a sulfonic acid group such as sodium dodecylbenzene sulfonate that has been conventionally used as a surfactant. It is possible to obtain a toner that suppresses the sulfonic acid group from remaining on the surface of the toner particles and suppresses the deterioration of the characteristics even under high temperature and high humidity. In addition, when the melting point of the fatty acid metal salt is less than 80 ° C., excessively small droplets are generated, and it becomes difficult to obtain a toner having a uniform particle diameter.

  The fatty acid metal salt used in the present invention preferably has a melting point equal to or higher than the polymerization temperature during polymerization. In general, fatty acid metal salts are also used as surfactants. Such an effect of the fatty acid metal salt as a surfactant is manifested when the melting point of the fatty acid metal salt is exceeded, that is, when the fatty acid metal salt is melted.

  Therefore, when the melting point of the fatty acid metal salt is lower than the polymerization temperature at the time of polymerization, the effect of the fatty acid metal salt as a surfactant is manifested, and the emulsified particles are also stably present in the solution to produce the emulsified particles. This makes it difficult to obtain a sharp particle size distribution. In the present invention, by using a fatty acid metal salt having a melting point equal to or higher than the polymerization temperature, it is possible to prevent the formation of emulsified particles and obtain a sharp particle size distribution. If the melting point of the fatty acid metal salt used in the present invention is 100 ° C. or higher, a sharper particle size distribution can be obtained.

The fatty acid metal salt having a melting point of 80 ° C. or higher is preferably a divalent or trivalent metal salt of a fatty acid having 30 or less carbon atoms. Examples of such include lauric acid (CH ₃ (CH ₂ ) ₁₀ COOH), myristic acid (CH ₃ (CH ₂ ) ₁₂ COOH), palmitic acid (CH ₃ (CH ₂ ) ₁₄ COOH) and stearic acid ( Divalent or trivalent metal salts such as CH ₃ (CH ₂ ) ₁₆ COOH) may be mentioned, and these may be used alone or in combination of two or more. Among these, a divalent or trivalent metal salt of stearic acid is preferable, and a divalent metal salt of stearic acid is more preferable.

Some examples of fatty acid metal salts having a melting point of 80 ° C. or higher include calcium laurate (Ca (C ₁₁ H ₂₅ COO) ₂ ), magnesium stearate (Mg (C ₁₇ H ₃₅ COO) ₂ ), calcium stearate ( Ca (C ₁₇ H ₃₅ COO) ₂ ), aluminum stearate (Al (C ₁₇ H ₃₅ COO) ₂ (OH)) and the like, among which magnesium stearate, calcium stearate and aluminum stearate are preferred. Used.

  The fatty acid metal salt having a melting point of 80 ° C. or higher is preferably used in an amount of 0.001 to 5 parts by weight with respect to 100 parts by weight of the vinyl monomer in the polymerizable composition. Such an amount of the fatty acid metal salt may be directly dispersed in the aqueous medium as described above, or may be contained in the polymerizable composition.

  Moreover, it is preferable to disperse a dispersion stabilizer in the aqueous medium. In the present invention, by using a dispersion stabilizer and a fatty acid metal salt having a melting point of 80 ° C. or higher as described above, the shape of the droplets is more preferable when the polymerizable composition is dispersed in an aqueous medium. be able to.

  As the dispersion stabilizer used in the present invention, for example, a colloid of a poorly water-soluble metal compound is preferable. Examples of poorly water-soluble metal compounds include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide; water And metal hydroxides such as aluminum oxide, magnesium hydroxide, and ferric hydroxide.

  Among these, a colloid of a poorly water-soluble metal hydroxide is preferable because it can narrow the particle size distribution of the toner particles to be generated and improve the sharpness of the image. In particular, when the crosslinkable monomer is not copolymerized, the fixing property and storage stability of the toner can be improved by using a colloid of a hardly water-soluble metal hydroxide as a dispersion stabilizer.

  The colloid of such a poorly water-soluble metal hydroxide is not limited by its production method. For example, the poorly water-soluble metal hydroxide obtained by adjusting the pH of the aqueous solution of the water-soluble polyvalent metal compound to 7 or more. A colloid of a slightly water-soluble metal hydroxide formed by a reaction in a water phase of a water-soluble polyvalent metal compound and an alkali metal hydroxide is preferred.

  Specifically, for example, after dissolving the water-soluble polyvalent metal compound by acidifying the aqueous medium, before dispersing the fatty acid metal salt and the polymerizable composition, or the polymerizable composition containing the fatty acid metal salt, Alternatively, the colloid of poorly water-soluble metal hydroxide is precipitated by setting the pH of the aqueous medium to 7 or more during dispersion.

The colloid of a poorly water-soluble metal compound used in the present invention has a number particle size distribution D ₅₀ (50% cumulative value of the number particle size distribution) of 0.5 μm or less and a D ₉₀ (90% cumulative value of the number particle size distribution). ) Is preferably 1 μm or less. When the colloid particle size is larger than this, the stability of suspension polymerization is lost, which is not preferable.

  The dispersion stabilizer is preferably in a proportion of 0.1 to 20 parts by weight with respect to 100 parts by weight of the vinyl monomer in the polymerizable composition. If the amount of the dispersion stabilizer used is too small, it is difficult to obtain sufficient polymerization stability, and polymerized aggregates are easily generated. On the contrary, if the amount of the dispersion stabilizer used is too large, the viscosity of the aqueous medium is excessively increased, and small droplets cannot be obtained.

  In the present invention, a water-soluble polymer can be used as a dispersion stabilizer as required. Examples of the water-soluble polymer include polyvinyl alcohol, methyl cellulose, gelatin and the like.

（但し、Ｒ^１が水素または炭素数が２０以下のアルキル基、アリル基、アリール基であり、Ｒ^２が水素または炭素数が１０以下のアルキル基、アリル基、アリール基、アルコキシ基であり、Ｒ^３が水素または炭素数が１０以下のアルキル基、アリル基、アリール基、アルコキシ基であり、Ｒ^４が水素または炭素数が１０以下のアルキル基、アリル基、アリール基、アルコキシ基である） In the present invention, it is preferable to use an imidazole compound represented by the following chemical formula (1) in combination as a dispersion aid. It is preferable to use such a dispersion aid because the polymerization stability can be further improved.

(However, R ¹ is hydrogen or an alkyl group having 20 or less carbon atoms, an allyl group, or an aryl group; R ² is hydrogen or an alkyl group having 10 or less carbon atoms, an allyl group, an aryl group, or an alkoxy group; R ³ is hydrogen or an alkyl group having 10 or less carbon atoms, allyl group, aryl group or alkoxy group, and R ⁴ is hydrogen or an alkyl group having 10 or less carbon atoms, allyl group, aryl group or alkoxy group)

  Next, the polymerizable composition used in the present invention will be described. The polymerizable composition in the present invention specifically includes a vinyl monomer as a polymerizable monomer as an essential component, in addition to other monomers such as a crosslinkable monomer and a macromonomer, if necessary, a charge control agent, It contains a colorant, a polymerization initiator, and other additives. Moreover, as mentioned above, the polymerizable composition may contain a fatty acid metal salt having a melting point of 80 ° C. or higher.

  Examples of the vinyl monomer as the polymerizable monomer include styrene derivatives such as styrene, vinyl toluene, and α-methylstyrene; acrylic acid, methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and acrylic acid. 2-ethylhexyl, dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, etc. (Meth) acrylic acid derivatives; ethylenically unsaturated monoolefins such as ethylene, propylene and butylene; vinyl halides such as vinyl chloride, vinylidene chloride and vinyl fluoride; vinyl acetate Vinyl esters such as vinyl propionate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and methyl isopropenyl ketone; nitrogen-containing compounds such as 2-vinyl pyridine, 4-vinyl pyridine and N-vinyl pyrrolidone Vinyl compounds; and the like.

  These vinyl monomers may be used alone or in combination. In particular, a combination of a styrene derivative and a (meth) acrylic acid derivative is preferably used. Preferred examples include styrene and butyl acrylate (that is, n-butyl acrylate), styrene and 2-ethylhexyl acrylate (that is, 2). -Ethylhexyl acrylate).

  The vinyl monomer used in the present invention is preferably one that can form a polymer having a glass transition temperature of 70 ° C. or lower, preferably 10 to 60 ° C., more preferably 15 to 50 ° C. If the vinyl monomer forms a glass transition temperature exceeding 70 ° C., the fixing temperature of the toner is increased, the OHP permeability is lowered, and it is not suitable for high speed copying and printing.

  The glass transition temperature (Tg) of the polymer is a calculated value (referred to as “calculated Tg”) calculated according to the type and use ratio of the vinyl monomer used. When only one vinyl monomer is used, the Tg of the homopolymer formed from the vinyl monomer is defined as the Tg of the polymer in the present invention. For example, since Tg of polystyrene is 100 ° C., when styrene is used alone as a vinyl monomer, a polymer having Tg of 100 ° C. is formed.

  When two or more types of vinyl monomers are used and the polymer to be produced is a copolymer, the Tg of the copolymer is calculated according to the type and proportion of the vinyl monomer used. For example, when 70% by weight of styrene and 30% by weight of n-butyl acrylate are used as vinyl monomers, the Tg of the styrene-n-butyl acrylate copolymer produced at this vinyl monomer ratio is 35 ° C. This vinyl monomer forms a polymer having a Tg of 35 ° C.

  When a plurality of vinyl monomers are used, it is not always necessary that all vinyl monomers can form a polymer having a Tg of 70 ° C. or lower. That is, in the case where a plurality of types of vinyl monomers are used, it is preferable that the Tg of the copolymer formed from them is 70 ° C. or less, but a homopolymer obtained by polymerizing individual vinyl monomers alone. The Tg may exceed 70 ° C.

  For example, the Tg of a homopolymer of styrene is 100 ° C., but by using styrene mixed with a vinyl monomer (for example, n-butyl acrylate) that forms a low Tg homopolymer, the Tg is 70 ° C. or less. If a copolymer can be formed, styrene may be used as a kind of vinyl monomer.

  It is preferable that the polymerizable composition in the present invention contains a crosslinkable monomer together with the vinyl monomer. By containing a crosslinkable monomer in the polymerizable composition, it is possible to improve the storage stability of the toner.

  Examples of the crosslinkable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; diethylenically unsaturated carboxylic acid esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; N, N-divinylaniline, And divinyl compounds such as divinyl ether; compounds having three or more vinyl groups; and the like.

  These crosslinkable monomers can be used alone or in combination of two or more. The crosslinkable monomer is preferably 0.01 to 5 parts by weight and more preferably 0.05 to 2 parts by weight with respect to 100 parts by weight of the vinyl monomer.

  It is preferable that the polymerizable composition in the present invention further contains a macromonomer (also referred to as a macromer). A macromonomer is a relatively long linear molecule having a polymerizable functional group (for example, an unsaturated group such as a carbon-carbon double bond) at the end of a molecular chain.

  As the macromonomer, an oligomer or polymer having a vinyl polymerizable functional group at the end of the molecular chain and having a number average molecular weight of about 1000 to 30000 is preferable. When a macromonomer having a small number average molecular weight is used, the surface portion of the toner particles becomes soft and the storage stability tends to be lowered. On the other hand, when a macromonomer having a large number average molecular weight is used, the fluidity of the macromonomer is deteriorated, and the fixability and storage stability of the toner are lowered.

  Examples of the vinyl polymerizable functional group at the end of the molecular chain 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 used in the present invention is preferably one having a glass transition temperature higher than that of a polymer obtained by polymerizing a vinyl monomer. The level of Tg between the polymer obtained by polymerizing the vinyl monomer and the macromonomer is relative. For example, in the case where the vinyl monomer forms a polymer having Tg = 70 ° C., the macromonomer only needs to have a Tg exceeding 70 ° C.

  In the case where the vinyl monomer forms a polymer having Tg = 20 ° C., the macromonomer may have, for example, Tg = 60 ° C. The Tg of the macromonomer is a value measured with an ordinary measuring instrument such as DSC.

  Examples of the macromonomer used in the present invention 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; polysiloxane skeleton And the like.

  Among these macromonomers, a hydrophilic polymer, in particular, a polymer obtained by polymerizing methacrylic acid ester or acrylic acid ester alone or in combination thereof is suitable for the present invention.

  The macromonomer is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the vinyl monomer, more preferably 0.03 to 5 parts by weight, and 0.05 to 1 part by weight. Further preferred. When the content of the macromonomer is small, it is difficult to improve the storage stability and the fixing property of the toner in a balanced manner, and when the content of the macromonomer is increased, the toner fixing property tends to be lowered.

  As the charge control agent contained in the polymerizable composition, those generally known as charge control agents can be widely used. Among such charge control agents, as a positively chargeable charge control agent, for example, a quaternary ammonium salt or a copolymer resin having a quaternary ammonium group is preferably used. In the present invention, even when such a positively chargeable charge control agent is used, a positively chargeable toner can be easily produced by containing a fatty acid metal salt having a melting point of 80 ° C. or higher as described above. can do.

  The content of such a charge control agent is preferably 0.01 to 20 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the vinyl monomer.

  Examples of the colorant contained in the polymerizable composition include dyes such as carbon black, nigrosine base, aniline blue, calco oil blue, chrome yellow, ultramarine blue, orient oil red, phthalocyanine blue, and malachite green oxalate. Pigments; magnetic particles such as cobalt, nickel, iron sesquioxide, iron tetroxide, manganese iron oxide, zinc iron oxide, nickel iron oxide; and the like.

  The dye or pigment is preferably 0.1 to 20 parts by weight and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the vinyl monomer. The magnetic particles are preferably 1 to 100 parts by weight and more preferably 5 to 50 parts by weight with respect to 100 parts by weight of the vinyl monomer.

  In the polymerizable composition of the present invention, for the purpose of uniformly dispersing the colorant in the toner particles, for example, a lubricant such as oleic acid or stearic acid; a dispersion aid such as a silane-based or titanium-based coupling agent; May be included. Such lubricants and dispersion aids are preferably used at a ratio of about 1/1000 to 1/1 based on the weight of the colorant.

  The polymerizable composition in the present invention may contain a polymerization initiator. In addition, you may add a polymerization initiator to an aqueous medium before superposition | polymerization instead of making it contain in a polymeric composition.

  Examples of the polymerization initiator include radical polymerization initiators, specifically, persulfates such as potassium persulfate and ammonium persulfate; 4,4-azobis (4-cyanovaleric acid), dimethyl-2,2′- Azobis (2-methylpropyronate), 2,2-azobis (2-amidinopropane) dihydrochloride, 2,2-azobis-2-methyl-N-1,1-bis (hydroxymethyl) -2-hydroxy Azo compounds such as ethylpropioamide, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (1-cyclohexanecarbonitrile) Methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide , T- butyl peroxy-2-ethylhexanoate, di - isopropyl peroxydicarbonate, peroxides di -t- butyl peroxy isophthalate, and the like; and the like can be exemplified.

  Among these radical polymerization initiators, oil-soluble radical initiators are preferable, and organic peroxides having a 10-hour half-life temperature of 60 to 80 ° C., preferably 65 to 80 ° C., and a molecular weight of 25 ° C. or less. An oil-soluble radical initiator selected from is preferred.

  Among oil-soluble radical initiators, t-butylperoxy-2-ethylhexanoate is particularly suitable because it has a low odor during printing and has little influence on the environment due to volatile components such as odor.

  The polymerization initiator is preferably used in an amount of 0.001 to 5 parts by weight with respect to 100 parts by weight of the vinyl monomer in the polymerizable composition. As described above, such an amount of the polymerization initiator may be contained in the polymerizable composition or may be added to the aqueous medium. If the amount of the polymerization initiator used is less than the above range, the polymerization rate becomes slow, and if it exceeds the above range, it is not economical because it is not economical.

  In addition to the above, the polymerizable composition in the present invention may contain various additives such as a molecular weight regulator and a release agent as necessary.

  Examples of the molecular weight modifier include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and n-octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide; and the like. The molecular weight regulator is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, with respect to 100 parts by weight of the vinyl monomer.

  Examples of the release agent include low molecular weight polyolefins such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; paraffin waxes; higher fatty acid compounds such as higher fatty acids and esters or metal salts thereof; it can. The release agent is preferably 0.1 to 20 parts by weight and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the vinyl monomer.

  The polymerizable composition in the present invention is produced by blending the above-described components and then mixing the mixture so as to be sufficiently uniform using, for example, a ball mill or the like to obtain a mixed solution. Then, as described above, the mixed liquid as the polymerizable composition is dispersed and polymerized in an aqueous medium to produce a toner.

  The toner of the present invention preferably has a toluene insoluble content of 50% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less. When the toluene insoluble content of the toner is more than 50% by weight, the fixability tends to be lowered, which is not preferable. The toluene-insoluble component means that the polymer component forming the toner is placed in an 80-mesh wire mesh cage, immersed in toluene at room temperature for 24 hours, and the weight of the solid matter remaining in the basket is measured. It is expressed in weight% with respect to the components.

  An external additive can be used for the purpose of imparting various properties to the toner of the present invention produced by the production method as described above. Examples of external additives include metal oxides (aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.), nitrides (silicon nitride, etc.) and carbides (silicon carbide). Etc.), inorganic metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), carbon black, silica, etc. are used.

  These external additives are preferably 0.01 to 10 parts by weight, and more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the toner. External additives may be used singly or in combination, but those having been subjected to a hydrophobizing treatment are more preferable.

  The toner of the present invention may be used as a developer together with a carrier. The carrier used together with the toner of the present invention is not particularly limited, but is composed mainly of single and composite ferrites composed mainly of iron, copper, zinc, nickel, cobalt, manganese and chromium elements.

  The carrier is preferably one whose surface is coated with a resin or the like. As the method, a conventionally known method such as a method in which a coating material such as a resin is dissolved or suspended in a solvent and applied and adhered to a carrier, or a method of simply mixing with powder can be applied.

  Examples of the substance fixed to the carrier surface include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of di-tert-butylsalicylic acid, styrene resin, acrylic resin, Polyamide, polyvinyl butyral, nigrosine, aminoacrylate resin, basic dye and its lake, silica fine powder, alumina fine powder and the like are suitably used alone or in combination.

  When the toner and carrier in the present invention are mixed to obtain a developer, the mixing ratio is 2 to 15% by weight, preferably 4 to 13% by weight as the toner content in the developer. If the toner content is less than 2% by weight, the image density is low and impractical, and if it exceeds 15% by weight, fog is increased.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, these Examples do not limit the scope of the present invention.

(Example 1)
0.4 parts by weight of magnesium stearate (melting point: 145 to 160 ° C.) as a fatty acid metal salt having a melting point of 80 ° C. or higher, 80 parts by weight of styrene as a vinyl monomer and 20 parts by weight of butyl acrylate, divinylbenzene as a crosslinkable monomer 2 parts by weight, 3 parts by weight of a styrene / acrylic copolymer having a quaternary ammonium functional group as a charge control agent (charge control resin, manufactured by Fujikura Kasei Co., Ltd.), copper phthalocyanine (C.I. P.B 15: 3) 5 parts by weight and 2 parts by weight of 2-phenylimidazole as a dispersion aid were sufficiently mixed.

  Further, 2 parts by weight of 2,2′-azobis- (2,4-dimethylvaleronitrile) as a polymerization initiator is added to this mixture and mixed thoroughly to obtain a polymerizable composition (oil phase). Obtained.

  Next, 7 parts by weight of calcium phosphate serving as a dispersion stabilizer was added to 670 parts by weight of distilled water as an aqueous medium, and the calcium phosphate was dissolved with hydrochloric acid (hereinafter referred to as an aqueous phase). The oil phase was added to the aqueous phase, and dissolved calcium phosphate was precipitated by making it into an alkaline aqueous solution, and mixed well to form a suspension.

  The granulation property of this suspension was evaluated. Evaluation of the granulation property was made by visually observing the change in the shape of oil droplets when the suspension was allowed to stand for a certain period of time. The results are shown in Table 1. In the table, the granulation property is indicated by a five-step evaluation, and the best granulation property is indicated by “5”.

  Moreover, while stirring the suspension immediately after mixing with Claremix 15S (trade name, manufactured by M Technique Co., Ltd.) at 10,000 rotations per minute, at 60 ° C. for 3 hours, then at 80 ° C. for 5 hours, The reaction was completed under a nitrogen atmosphere to complete the polymerization. After completion of the polymerization, the suspension was solid-liquid separated, washed with dilute hydrochloric acid and water with ion exchange water, and sufficiently dried to obtain a toner.

  1.0 part by weight of hydrophobic silica is externally added to 100 parts by weight of the toner, and silicon-coated ferrite carrier (average particle size 50 μm) is 95.5 to 4.5 parts by weight of the externally added toner. Part by weight was added to obtain a developer.

  For this developer, the charge amount under normal temperature and normal humidity (20 ° C., 65% RH) and the charge amount under high temperature and high humidity (30 ° C., 80% RH) (H / H charge amount) were measured.

  In addition, using a copying machine NS8000C (trade name, manufactured by Kyocera Mita Co., Ltd.), white and blue images can be obtained under normal temperature and normal humidity (20 ° C, 65% RH), high temperature and high humidity (30 ° C, 80% RH). Copying and image fogging were evaluated. In the table, the evaluation of the fogging of the image is a five-level evaluation, and “5” indicates that the fogging of the image is extremely small. The results are shown in Table 2.

(Example 2)
A developer was prepared and evaluated in the same manner as in Example 1 except that magnesium stearate was changed to calcium stearate (melting point 150 ° C.) and 2 phenylimidazole as a dispersion aid was omitted.

(Example 3)
A developer was produced and evaluated in the same manner as in Example 1 except that magnesium stearate was changed to aluminum laurate (melting point: 80 ° C. or higher) and 2-phenylimidazole was removed as a dispersion aid.

Example 4
Magnesium stearate was changed to aluminum laurate (melting point of 80 ° C or higher), and 2-phenylimidazole as a dispersion aid was removed, and calcium phosphate as a dispersion stabilizer was dispersed in an aqueous layer as it was without dissolving with acid. A developer was produced and evaluated in the same manner as in Example 1 except for the above.

(Example 5)
A developer was produced and evaluated in the same manner as in Example 4 except that aluminum laurate was dispersed in the water phase instead of in the oil phase.

(Comparative Example 1)
A developer was produced and evaluated in the same manner as in Example 1 except that sodium dodecylbenzenesulfonate (melting point: 21 ° C.) was used instead of magnesium stearate.

(Comparative Example 2)
A developer was produced and evaluated in the same manner as in Example 1 except that sodium stearate (melting point 57 ° C.) was used instead of magnesium stearate.

  As is clear from Tables 1 and 2, in Examples 1 to 5, there was no significant change in the evaluation results of the charge amount and the image fogging between normal temperature and normal humidity and high temperature and high humidity. In Comparative Example 1, it was confirmed that the evaluation results of the charge amount and image fog under high temperature and high humidity were significantly lower than those under normal temperature and normal humidity.

  In addition, the particle size distribution of the toners obtained in Example 1 and Comparative Example 2 was measured. Table 3 shows the average particle size (μm) of the toners obtained in Example 1 and Comparative Example 2, and the ratio (number%) of those having a particle size of less than 4 μm and more than 13 μm. The particle size distribution was measured using Coulter Multisizer II (trade name, manufactured by Beckman Coulter, Inc.).

  As is apparent from Table 3, in Example 1 using a fatty acid metal salt having a melting point of 80 ° C. or higher, the generation of excessively small toner such as a particle size of less than 4 μm was suppressed, and the particle size was uniform. A toner can be obtained.

Claims (11)

Dispersing a fatty acid metal salt having a melting point of 80 ° C. or higher in an aqueous medium;
And a step of dispersing and polymerizing a polymerizable composition containing at least a vinyl monomer in the aqueous medium. Mixing at least a vinyl monomer and a fatty acid metal salt having a melting point of 80 ° C. or higher to obtain a polymerizable composition;
And a step of dispersing the polymerizable composition in an aqueous medium to polymerize the toner.   The method for producing a toner according to claim 1, wherein the fatty acid metal salt having a melting point of 80 ° C. or higher has a melting point equal to or higher than a polymerization temperature in the polymerization step.   After making the aqueous medium acidic and dissolving at least a metal salt soluble in an acidic solution and insoluble in an alkaline or neutral solution as a dispersion stabilizer, the fatty acid metal salt and the polymerizable composition, or The metal salt as the dispersion stabilizer is precipitated before or after dispersing the polymerizable composition containing a fatty acid metal salt, by making the aqueous medium an alkaline or neutral solution. 4. The method for producing a toner according to any one of 3 above.   The toner production method according to claim 1, wherein the fatty acid metal salt is a divalent or trivalent metal salt of a fatty acid having 30 or less carbon atoms.   6. The toner manufacturing method according to claim 5, wherein the fatty acid metal salt is a divalent metal stearate.   7. The toner manufacturing method according to claim 1, wherein the vinyl monomer includes at least one selected from an acrylic acid derivative and a methacrylic acid derivative, and a styrene derivative.   The said polymerizable composition contains the copolymer resin which has a quaternary ammonium salt or a quaternary ammonium group as a positively chargeable charge control agent. Toner manufacturing method. The method for producing a toner according to claim 1, wherein the polymerizable composition contains an imidazole compound represented by the following chemical formula (1) as a dispersion aid.

(However, R ¹ is hydrogen or an alkyl group having 20 or less carbon atoms, an allyl group, or an aryl group; R ² is hydrogen or an alkyl group having 10 or less carbon atoms, an allyl group, an aryl group, or an alkoxy group; R ³ is hydrogen or an alkyl group having 10 or less carbon atoms, allyl group, aryl group or alkoxy group, and R ⁴ is hydrogen or an alkyl group having 10 or less carbon atoms, allyl group, aryl group or alkoxy group)   A toner obtained by polymerizing at least a vinyl monomer, wherein the toner is produced using the method for producing a toner according to any one of claims 1 to 9.   The toner according to claim 10, wherein the toner is positively charged.