JP5025966B2 - Method for producing toner for electrophotography - Google Patents

Description

  The present invention relates to an electrophotographic toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.

  In recent years, from the pursuit of high image quality, development of a small particle size toner excellent in fixability has been desired. Styrene acrylic resins and polyesters are known as binder resins for toners, but polyesters are widely used because of their excellent durability. In addition, the toner production method includes a melt-kneading pulverization method and a wet production method such as an emulsion aggregation method. A small-particle toner using a binder resin mainly composed of polyester is produced by a melt-kneading pulverization method. In this case, pulverization control is difficult.

Patent Document 1 and Patent Document 2 disclose inventions relating to production by an emulsion aggregation method, which is a wet production method.
JP 2004-198598 A JP-A-9-311502

  In order to improve the offset resistance, it is effective to add a wax internally. However, when a toner is produced by a wet method, the wax has a low solubility and tends to be poorly dispersed. In particular, in the emulsion aggregation method, unlike the melt kneading method, a mechanical share is not added in the production process, so that it is generally more difficult to uniformly disperse the wax. If the dispersibility of the wax is not uniform, not only the low-temperature fixability is impaired, but offset is likely to occur, and the storage stability is also lowered. On the other hand, it is effective to increase the molecular weight, softening point, etc. of the resin in order to improve the offset resistance. However, since the low-temperature fixability deteriorates, it is difficult to achieve both offset resistance and low-temperature fixability.

  An object of the present invention is to provide an electrophotographic toner obtained by a method capable of efficiently producing even a small particle size toner, and having excellent offset resistance, low-temperature fixability and storage stability. There is to do.

  The present invention relates to an electrophotographic toner obtained by a method including a step of forming a raw material containing a binder resin into a solution, wherein the binder resin is a condensation polymerization resin in the presence of wax. The present invention relates to an electrophotographic toner comprising a resin obtained by polymerizing a raw material monomer and a raw material monomer of an addition polymerization resin.

  The toner for electrophotography of the present invention is a toner obtained by a method that can be produced efficiently even with a small particle size toner, and is excellent in all of offset resistance, low-temperature fixability, and storage stability.

  The electrophotographic toner of the present invention is an electrophotographic toner obtained by a method including a step of forming a raw material containing a binder resin into a solution, and the binder resin is subjected to condensation polymerization in the presence of wax. It has a great feature in that it contains a resin obtained by polymerizing a raw material monomer of an epoxy resin and a raw material monomer of an addition polymerization resin (hereinafter referred to as a wax-added composite resin). In the wax-added composite resin, since a hydrophobic wax exists in the polymerization reaction step of the raw material monomer of the condensation polymerization resin and the raw material monomer of the addition polymerization resin, the raw material of the addition polymerization resin that is also hydrophobic In the monomer polymerization reaction, the wax has affinity with the addition polymerization resin unit, and a resin in which the wax is remarkably highly dispersed is obtained as compared with the addition after polymerization. For this reason, even if the toner is produced by a wet process, such as an emulsion aggregation method, which does not take a share and tends to cause poor dispersion of the wax, a surprising effect is achieved that the wax can be uniformly dispersed.

  The wax in the composite resin with added wax is a fatty acid such as polyolefin wax such as polyethylene, polypropylene and polybutene, paraffin wax, Fischer-Tropsch wax, silicones, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide, etc. Examples include amides, montan wax, ozokerite, ceresin, microcrystalline wax, and other minerals and petroleum waxes. Among these, polyolefin wax, paraffin wax, and Fischer-Tropsch wax are preferred from the viewpoint of fixability. At least one selected from the group consisting of

  The melting point of the wax is preferably 60 to 150 ° C., more preferably 60 to 140 ° C., further preferably 65 to 130 ° C., and further preferably 70 to 120 ° C. from the viewpoints of fixability and offset resistance.

  The amount of wax, or the total amount when both are used in combination, is the dispersibility in the binder resin relative to 100 parts by weight of the total amount of the raw material monomer of the condensation polymerization resin and the raw material monomer of the addition polymerization resin. From the viewpoint, 0.5 to 25 parts by weight is preferable, 0.8 to 20 parts by weight is more preferable, and 1.0 to 15 parts by weight is further preferable.

  The polycondensation resin is preferably at least one selected from the group consisting of polyester, polyester / polyamide and polyamide, and among these, polyester is more preferable.

  The polyester is obtained by polycondensing an alcohol component and a carboxylic acid component, which are raw material monomers.

  Alcohol components include alkylenes of bisphenol A such as polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane Dioxides such as oxide adducts, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, bisphenol A, hydrogenated bisphenol A, and Examples include trihydric or higher polyhydric alcohols such as sorbitol, pentaerythritol, glycerol, and trimethylolpropane.

  On the other hand, carboxylic acid components include dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isooctenyl succinic acid, iso Dicarboxylic acids such as succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms such as octyl succinic acid, anhydrides of these acids and lower alkyl (1 to 3 carbon atoms) esters Compounds, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, derivatives of these acids, ie, anhydrides and lower alkyls (1 to 3) Trivalent or higher polyvalent carboxylic acid compounds such as esters and the like. It should be noted that monomers that can be both reactive monomers such as maleic acid, fumaric acid, and acrylic acid are also added only to the polycondensation reaction, for example, when they are added after the completion of the addition polymerization reaction by changing the reaction process, It can be used as a monomer involved. In that case, these monomers are not a bireactive monomer but used as a raw material monomer for a condensation polymerization resin.

  Among dicarboxylic acid compounds, terephthalic acid, succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms, anhydrides of these acids, and lower alkyls (1 to 3 carbon atoms) from the viewpoint of chargeability and fixing properties Esters are preferred, and among trivalent or higher polyvalent carboxylic acid compounds, trimellitic acid and its acid anhydride are preferred from the viewpoint of being inexpensive and easy to control the reaction.

  For the condensation polymerization of the alcohol component and the carboxylic acid component, an esterification catalyst such as a tin compound such as dibutyltin oxide or tin dioctylate or a titanium compound may be appropriately used.

  Polyester / polyamide is obtained by condensation polymerization of these raw material monomers using the amide component in addition to the alcohol component and carboxylic acid component, and the polyamide uses the amide component in addition to the carboxylic acid component. These raw material monomers are obtained by condensation polymerization.

  Examples of the amide component include various known polyamines, aminocarboxylic acids, aminoalcohols, etc., preferably hexamethylenediamine and ε-caprolactam.

  The above raw material monomers also include those normally classified as ring-opening polymerization monomers, but these are hydrolyzed by condensation due to the presence of water or the like produced by the condensation polymerization reaction of other monomers. Therefore, it is considered to be included in the raw material monomer of the condensation polymerization resin in a broad sense.

  Examples of the addition polymerization resin include vinyl resins obtained by radical polymerization reaction.

  As raw material monomers for vinyl resins, styrene compounds such as styrene and α-methylstyrene; ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; halovinyls such as vinyl chloride; vinyl acetate; Vinyl esters such as vinyl propionate; alkyl (1-18) esters of (meth) acrylic acid, esters of ethylenic monocarboxylic acids such as dimethylaminoethyl (meth) acrylate; vinyl ethers such as vinyl methyl ether Vinylidene halides such as vinylidene chloride; N-vinyl compounds such as N-vinylpyrrolidone, and the like. Among these, styrene is used from the viewpoint of chargeability and from the viewpoint of adjusting the fixing property and glass transition point. , Alkyl esters of (meth) acrylic acid are preferred, styrene, 2- Ethylhexyl acrylate, long-chain alkyl (having 12 to 18 carbon atoms) of butyl acrylate and acrylic acid esters are more preferable. The content of styrene is preferably 50 to 90% by weight, more preferably 65 to 85% by weight, and still more preferably 70 to 85% by weight in the raw material monomer of the vinyl resin. The monomer ratio of styrene to the alkyl ester of (meth) acrylic acid is preferably 50/50 to 95/5, more preferably 70/30 to 95/5.

  In addition, a polymerization initiator, a crosslinking agent, or the like may be used as needed for the addition polymerization of the raw material monomer of the vinyl resin.

  In the present invention, the weight ratio of the condensation polymerization resin to the addition polymerization resin, that is, the weight ratio of the condensation polymerization resin raw material monomer to the addition polymerization resin raw material monomer, the continuous phase is the condensation polymerization resin, Since the phase is preferably an addition polymerization resin, 50/50 to 95/5 is preferable, and 60/40 to 95/5 is more preferable.

  In the present invention, in addition to the wax, the raw material monomer of the condensation polymerization resin, and the raw material monomer of the addition polymerization resin, the wax-added composite resin may be any one of the raw material monomer of the condensation polymerization resin and the addition polymerization resin. A resin obtained by using a compound (both reactive monomers) capable of reacting with both is preferable (hereinafter referred to as a wax-added hybrid resin).

  As the both reactive monomers, at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group and a secondary amino group in the molecule, and an ethylenically unsaturated bond A compound having the above formula is preferred, and by using such a bireactive monomer, the dispersibility of the resin to be the dispersed phase can be further improved. Specific examples of the both reactive monomers include, for example, acrylic acid, fumaric acid, methacrylic acid, citraconic acid, maleic acid, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, and carboxylic acids thereof. Derivatives such as anhydrides, alkyl (1 to 2 carbon atoms) esters and the like can be mentioned, and among these, acrylic acid, methacrylic acid, fumaric acid, maleic acid and derivatives of these carboxylic acids are preferable from the viewpoint of reactivity.

The amount of the bireactive monomer used is not particularly limited. For example, when the bireactive monomer is a carboxylic acid or a derivative thereof, the amount of the bireactive monomer is the amount of the carboxylic acid component that is a raw material monomer of the condensation polymerization resin. It shall be included in a part. In this case, the amount of the amphoteric monomer used is the formula (A): from the viewpoint of finely and uniformly dispersing the wax.
0.10 <X / Y <0.50 (A)
(In the formula, X is the molar fraction (mol%) of the carboxylic acid component which is the raw material monomer of the condensation polymerization resin and the both reactive monomers in the both reactive monomers, and Y is the raw material of the condensation polymerization resin. (The weight fraction of the raw material monomer of the addition polymerization resin in the total amount of monomer and addition polymerization resin raw material monomer (% by weight) x the number of functional groups in one molecule of both reactive monomers))
Is preferably satisfied. In the formula (A), X is related to the graft length of the condensation polymerization resin unit, and Y is related to the graft ratio at which the condensation polymerization resin unit is grafted to the addition polymerization resin unit. That is, the wax-added composite resin in the present invention is preferably a resin having a specific graft ratio and graft length from the viewpoint of compatibility with the wax. Formula (A) is preferably 0.15 <X / Y <0.45, more preferably 0.20 <X / Y <0.40. In the present invention, even if the monomer can be a bireactive monomer, the monomer used in a state that only participates in the condensation polymerization reaction as described above is not treated as a bireactive monomer.

  In the present invention, the wax-added composite resin includes a wax, a raw material monomer for the condensation polymerization resin, and a raw material monomer for the addition polymerization resin in advance from the viewpoint of uniformity of the wax, the condensation polymerization resin, and the addition polymerization resin. It is preferably a resin obtained by mixing and performing a polycondensation reaction and an addition polymerization reaction in the same reaction vessel in parallel, and the wax-added composite resin is a hybrid resin obtained by using both reactive monomers. In some cases, a mixture of wax, a monomer of a condensation polymerization resin raw material and a monomer of an addition polymerization raw material is mixed with both reactive monomers in advance, and the condensation polymerization reaction and the addition polymerization reaction are performed in parallel in the same reaction vessel. It is preferable that it is resin obtained by performing.

  In the present invention, the progress and completion of the polycondensation reaction and the addition polymerization reaction in the presence of the wax do not have to be simultaneous in time. The reaction temperature and time are appropriately selected according to the respective reaction mechanisms, and the reaction Can be progressed and completed. For example, wax, condensation polymerization resin raw material monomer, addition polymerization resin raw material monomer, both reactive monomers, etc. are mixed, and first, the addition polymerization reaction is carried out mainly under temperature conditions suitable for addition polymerization reaction, for example, 50 to 180 ° C. After forming an addition polymerization resin having a functional group capable of polycondensation reaction, the reaction temperature is then increased to a temperature condition suitable for the polycondensation reaction, for example, 190 to 270 ° C. Examples thereof include a method of forming a condensation polymerization resin.

  The molecular weight and the like of the wax-containing composite resin in the present invention are not particularly limited. Further, the insoluble matter in the solvent used in the production of the toner of the present invention derived from the resin component of the wax-added composite resin is the particle size of the resulting emulsion, that is, from the viewpoint of image quality, 3% by weight or less is preferable, 0.5% by weight or less is more preferable, and substantially 0% by weight is further preferable.

  The softening point of the wax-added composite resin is preferably from 80 to 160 ° C, more preferably from 85 to 150 ° C, further preferably from 90 to 140 ° C, and further preferably from 95 to 130 ° C, from the viewpoints of fixability and durability. The softening point can be easily adjusted by adjusting the raw material monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions.

  The glass transition point of the wax-added composite resin is preferably 40 to 70 ° C., more preferably 45 to 65 ° C., and still more preferably 50 to 65 ° C. from the viewpoint of fixability and durability. The glass transition point can be easily adjusted by adjusting the raw material monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions.

  The acid value of the wax-added composite resin is preferably 5 to 30 mgKOH / g, more preferably 5.5 to 29 mgKOH / g, and further preferably 6 to 27 mgKOH / g from the viewpoint of chargeability.

  In the present invention, the content of the wax-added composite resin is preferably 20 to 100% by weight, more preferably 40 to 100% by weight, and more preferably 60 to 100% by weight in the binder resin from the viewpoint of fixability and environmental characteristics. Is more preferable. In addition to the wax-added composite resin, a known resin such as polyester or styrene acrylic resin may be contained as a binder resin.

  Further, the toner of the present invention includes additives such as a coloring agent, a release agent, a charge control agent, a conductivity adjusting agent, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, and an antioxidant. You may contain suitably.

  There is no restriction | limiting in particular as a coloring agent, A well-known coloring agent is mentioned, According to the objective, it can select suitably. Specifically, carbon black, inorganic complex oxide, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, balkan orange, watch young red, permanent red, brilliantamine 3B, Brilliantamine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, etc. Various pigments, acridine, xanthene, azo, benzoquinone, azine, anthraquinone, indico, thioindico, Roshianin system, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, thiazine, various dyes thiazole, etc. may be used in conjunction with one or more kinds. The content of the colorant 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 binder resin.

  Examples of the release agent include low molecular weight polypropylene, low molecular weight polyethylene, low molecular weight polypropylene polyethylene copolymer, aliphatic hydrocarbon waxes such as microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and their derivatives and carna Examples include ester waxes such as uba wax, montan wax, sazol wax and their deoxidized wax, and derivatives thereof, fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts and the like. These can be used alone or in combination. Derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. Among these, aliphatic hydrocarbon waxes are preferable from the viewpoint of releasability and stability, and at least one selected from the group consisting of polyolefin wax, paraffin wax and Fischer-Tropsch wax from the viewpoint of dispersibility. Species are more preferred. The toner of the present invention contains a composite resin with an internal wax, and the addition polymerization resin unit functions as a dispersant. Therefore, at least one selected from the group consisting of polyolefin wax, paraffin wax, and Fischer-Tropsch wax is used. When seeds are used, it is estimated that the dispersibility of the wax is further increased. The content of the release agent is preferably 0.1 to 10 parts by weight, more preferably 0.8 to 9 parts by weight, and further preferably 1 to 8 parts by weight with respect to 100 parts by weight of the binder resin.

  Examples of the charge control agent include chromium azo dyes, iron azo dyes, aluminum azo dyes, and salicylic acid metal complexes. The content of the charge control agent is preferably 0.1 to 8 parts by weight and more preferably 0.5 to 7 parts by weight with respect to 100 parts by weight of the binder resin. Various charge control agents may be used alone or in combination of two or more.

The method for producing the electrophotographic toner of the present invention is not particularly limited as long as it is a dry toner obtained by a method including a step of forming a raw material containing at least a binder resin into a solution. As a specific example of the method for producing the toner of the present invention, a mixed solution prepared by dissolving or dispersing a raw material containing a binder resin in an organic solvent is introduced into an aqueous medium and fine particles are formed by suspension granulation. A method of agglomerating the fine particles; a method of emulsion polymerization of a radical polymerizable monomer solution in which a binder resin is dissolved to obtain resin fine particles, and fusing the resin fine particles in an aqueous medium (Japanese Patent Application Laid-Open No. 2001). A method in which a resin heated melt composed of a raw material containing a binder resin is dispersed in an aqueous medium not containing an organic solvent and then dried while maintaining the molten state of the binder resin (see Japanese Patent No. 42568). JP, 2001-235904, A) etc. are mentioned, but as a method in which binder resin is not especially limited, primary particles containing at least binder resin are made into an aqueous medium in the presence of a nonionic surfactant. In step of generating (1), and aggregating the primary particles, the method comprising the step of coalescing (2) is preferred.

  By mixing the binder resin and the nonionic surfactant, the viscosity of the mixture is reduced, and the binder resin can be atomized. This is because the decrease in the viscosity of the mixture is caused by the nonionic interface. This is because the activator is compatible with the binder resin and the softening point of the resin apparently decreases. If this phenomenon is utilized to reduce the apparent softening point of the binder resin compatible with the nonionic surfactant to below the boiling point of water, the resin alone has a melting point or softening point of 100 ° C. or higher. Even with the binder resin, a dispersion liquid in which the binder resin is dispersed in water can be obtained by dropping water at normal pressure. Since at least water and a nonionic surfactant are sufficient, it can be applied to resins that are insoluble in organic solvents, and there is no need to pay for facilities for collecting organic solvents or maintaining the work environment. In the present invention using a chemical action by an activator, a special apparatus required when using a mechanical means is not required, so that there is an advantage that a resin dispersion can be produced economically. Accordingly, the aqueous medium may contain a solvent such as an organic solvent, but preferably contains 95% by weight or more, more preferably 99% by weight or more of water. Even if only water is used without using an organic solvent, the binder resin can be atomized.

  Nonionic surfactants include, for example, polyoxyethylene nonyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl allyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkyl ethers, polyoxyethylene sorbitan mono Polyoxyethylene sorbitan esters such as laurate, polyoxyethylene sorbitan monostearate, polyoxyethylene fatty acid esters such as polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, oxyethylene / Oxypropylene block copolymer and the like. Further, an anionic surfactant or a cationic surfactant may be used in combination with the nonionic surfactant as long as the effects of the present invention are not impaired.

  In selecting a nonionic surfactant, it is important to select a nonionic surfactant having good compatibility with the resin. In order to obtain a stable binder resin dispersion, the HLB of the nonionic surfactant is preferably 12 to 18, and depending on the type of the binder resin, two or more different HLB nonionic interfaces may be used. More preferably, an activator is used. For example, in the case of a highly hydrophilic resin, it is sufficient to use at least one kind of nonionic surfactant having an HLB of 12 to 18. However, in the case of a highly hydrophobic resin, a low HLB, for example, an HLB of 7 It is preferable to adjust the weighted average of both HLBs to 12-18 by using about ~ 10 and those having high HLB, for example, 14-20 HLB. In this case, it is presumed that those having an HLB of about 7 to 10 are compatibilizing the resin, and those having a high HLB are stabilizing the dispersion of the resin in water.

  Further, when using a colorant, the nonionic surfactant is preferably adsorbed on the colorant and dispersed in the binder resin. By adjusting the HLB of the nonionic surfactant to the above range, the nonionic surfactant is easily adsorbed on the colorant surface, and at the same time, the colorant is present as a colloidal dispersion in an aqueous medium. It is preferable because it stably exists in the binder resin.

  The cloud point of the nonionic surfactant is preferably 70 to 105 ° C., more preferably 80 to 105 ° C. when the binder resin is atomized under normal pressure and water.

  From the viewpoint of lowering the melting point of the binder resin, the amount of the nonionic surfactant used is preferably 5 parts by weight or more with respect to 100 parts by weight of the binder resin, and controls the nonionic surfactant remaining in the toner. From this viewpoint, the amount is preferably 80 parts by weight or less. Therefore, from the viewpoint of making these compatible, the amount of the nonionic surfactant used is preferably 5 to 80 parts by weight, more preferably 10 to 70 parts by weight, and more preferably 20 to 60 parts by weight with respect to 100 parts by weight of the binder resin. Part by weight is more preferred.

  In the step (1), when the primary particles containing the binder resin are produced in the aqueous medium in the presence of the nonionic surfactant, the temperature in the system depends on the dispersibility of the nonionic surfactant and From the viewpoint of preventing a decrease in dispersion efficiency, it is desirable to keep the nonionic surfactant within a temperature range of 10 ° C., preferably 8 ° C., more preferably 5 ° C. above and below the cloud point.

  In step (1), for example, an aqueous medium (preferably deionized water or distilled water) is dropped in a state where the mixture of the binder resin and the nonionic surfactant is stirred and uniformly mixed in the system. It is preferable to do. In addition, when using a coloring agent, it is preferable to pay attention so that the binder resin containing the coloring agent compatible with the nonionic surfactant does not separate from water.

  The mixing amount of the aqueous medium is preferably 100 to 3000 parts by weight, more preferably 400 to 3000 parts by weight, more preferably 800 to 3000 parts by weight with respect to 100 parts by weight of the binder resin, from the viewpoint of obtaining uniform aggregated particles in the subsequent steps. Is more preferable.

  The particle size of the primary particles can be controlled by the amount of the nonionic surfactant, the stirring force, and the addition rate of water. In the step (1), the rate at which the aqueous medium is added to the mixture containing at least the binder resin and the nonionic surfactant is preferably 0.1 to 50 g / min per 100 g of the mixture from the viewpoint of obtaining uniform primary particles. 0.5-40 g / min is more preferable, and 1-30 g / min is more preferable.

  In addition, when the binder resin has an acidic group such as a carboxyl group or a sulfone group, water may be added after neutralizing all or part of the binder resin or while neutralizing the binder resin. When the binder resin having an acidic group is used, the self-emulsifying factor of the resin is a factor controlling the particle size of the primary particles in addition to the factor of the nonionic surfactant.

  A dispersant can be used as necessary for the purpose of lowering the melt viscosity and melting point of the binder resin and improving the dispersibility of the primary particles produced. Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate; sodium dodecylbenzenesulfonate, sodium octadecylsulfate, sodium oleate, Anionic surfactants such as sodium laurate and potassium stearate; Cationic surfactants such as laurylamine acetate, stearylamine acetate and lauryltrimethylammonium chloride; Amphoteric surfactants such as lauryldimethylamine oxide; Tricalcium phosphate, Water Examples thereof include inorganic salts such as aluminum oxide, calcium sulfate, calcium carbonate, and barium carbonate. The blending amount of the dispersant is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and still more preferably 10 parts by weight or less with respect to 100 parts by weight of the binder resin from the viewpoint of emulsion stability and detergency.

  The solid concentration in the system for preparing the dispersion of primary particles is preferably 7 to 50% by weight, more preferably 7 to 40% by weight from the viewpoint of the stability of the dispersion and the handling of the dispersion in the aggregation process. %, More preferably 10 to 30% by weight. The solid content includes non-volatile components such as a resin and a nonionic surfactant.

The volume-median particle size (D ₅₀ ) of the primary particles is preferably from 0.05 to 3 μm, more preferably from 0.05 to 1 μm, and even more preferably from 0.05 to 0.8 μm, from the viewpoint of uniformly agglomerating in subsequent steps. The average particle size of the primary particles refers to the volume median particle size (D ₅₀ ) and can be measured by a laser diffraction type particle size measuring machine or the like.

  Subsequently, the primary particles obtained in the step (1) are subjected to a step of aggregation and coalescence (step (2)).

  In the step (2), the solid concentration in the system in the aggregation step for aggregating the primary particles can be adjusted by adding water to the binder resin dispersion as necessary, thereby causing uniform aggregation. Therefore, 5 to 50% by weight is preferable, 5 to 30% by weight is more preferable, and 5 to 20% by weight is further preferable.

  Further, the pH in the system in the aggregation step is preferably 2 to 10, more preferably 2 to 9, from the viewpoint of achieving both the dispersion stability of the mixed solution and the aggregation property of fine particles such as a binder resin. 8 is more preferred.

  From the same viewpoint, the temperature in the system in the aggregation process is more preferably a softening point of the binder resin of −60 ° C. or more and a softening point or less.

  When the primary particles are aggregated, not only the primary particles obtained in step (1) are aggregated (homo-aggregation), but also a dispersion of resin fine particles obtained in the same manner as in step (1). Etc. may be mixed with a dispersion of primary particles to aggregate the primary particles and other resin fine particles (heteroaggregation).

  Further, additives such as a colorant, a charge control agent, and a release agent may be premixed in the binder resin when preparing the primary particles, and each additive is separately dispersed in a dispersion medium such as water. A dispersion may be prepared, mixed with primary particles, and subjected to an aggregation step. When the additive is previously mixed with the binder resin when preparing the primary particles, it is preferable to melt and knead the binder resin and the additive in advance. For melt kneading, it is preferable to use an open roll type biaxial kneader. The open roll type twin-screw kneader is a kneader in which two rolls are arranged close to each other in parallel, and a heating function or a cooling function can be imparted by passing a heat medium through each roll. Therefore, the open roll type twin screw kneader is an open type part to be melt kneaded and is provided with a heating roll and a cooling roll. The heat of kneading generated can be easily dissipated.

  In the aggregation process, an aggregating agent can be added in order to effectively perform aggregation. As an aggregating agent, a quaternary salt cationic surfactant, polyethyleneimine, or the like is used in an organic system, and an inorganic metal salt, a divalent or higher metal complex, or the like is used in an inorganic system. Examples of inorganic metal salts include metal salts such as sodium sulfate, sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, polyaluminum chloride, polyaluminum hydroxide, Examples thereof include inorganic metal salt polymers such as calcium sulfide.

  The amount of the flocculant used is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and even more preferably 10 parts by weight or less with respect to 100 parts by weight of the binder resin from the viewpoint of environmental resistance characteristics of the toner.

  The flocculant is preferably added after being dissolved in an aqueous medium, and it is preferable to sufficiently stir at the time of adding the flocculant and after the addition.

  Subsequently, the agglomerated particles containing at least the binder resin obtained in the aggregating step are heated and united (a uniting step).

  The temperature in the system in the coalescence process is from the viewpoint of the target toner particle size, particle size distribution, shape control, and particle fusing property, the softening point of the binder resin is −30 ° C. or more, and the softening point is + 10 ° C. The softening point is -25 ° C or higher and the softening point + 10 ° C or lower is more preferable, and the softening point -20 ° C or higher and the softening point + 10 ° C or lower is more preferable. The stirring speed is preferably a speed at which the aggregated particles do not settle.

  A toner can be obtained by subjecting the coalesced particles obtained in the step (2) to a solid-liquid separation step such as filtration, a washing step, and a drying step as appropriate.

  In the washing step, it is preferable to use an acid in order to remove metal ions on the toner surface in order to ensure sufficient charging characteristics and reliability as the toner. Further, it is preferable to completely remove the added nonionic surfactant by washing, and washing with an aqueous solution below the cloud point of the nonionic surfactant is preferred. The washing is preferably performed a plurality of times.

  In the drying step, any method such as a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like can be employed. The water content after drying of the toner is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of chargeability.

From the viewpoint of high image quality and productivity, the volume median particle size (D ₅₀ ) of the toner is preferably 1 to 10 μm, more preferably 2 to 9 μm, and even more preferably 3 to 8 μm. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  Further, the softening point of the toner is preferably 80 to 160 ° C., more preferably 80 to 140 ° C., and further preferably 80 to 130 ° C. from the viewpoint of low-temperature fixability. Moreover, 45-80 degreeC is preferable from the same viewpoint, and, as for a glass transition point, 50-70 degreeC is more preferable.

  An auxiliary agent such as a fluidizing agent may be added to the toner particle surface as an external additive to the toner obtained by the present invention. External additives include known fine particles such as silica fine particles, titanium fine particles, alumina fine particles, cerium oxide fine particles, carbon black and other inorganic fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate and silicone resin. Can be used.

  The number average particle diameter of the external additive is preferably 4 to 200 nm, more preferably 6 to 30 nm, and still more preferably 8 to 20 nm. The number average particle diameter of the external additive is determined using a scanning electron microscope or a transmission electron microscope.

  The blending amount of the external additive is preferably 1.0 to 5.0 parts by weight, and more preferably 1.5 to 3.5 parts by weight with respect to 100 parts by weight of the toner before processing with the external additive. However, when hydrophobic silica is used as the external additive, the desired effect can be obtained by using 0.8 to 3.0 parts by weight of hydrophobic silica with respect to 100 parts by weight of the toner before processing with the external additive.

  The electrophotographic toner of the present invention can be used as a non-magnetic one-component developer or a two-component developer mixed with a carrier.

1. Resin acid value
Measured according to the method of JIS K0070. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

2. Softening point and glass transition point of resin and toner (1) Softening point Using a flow tester (Shimadzu Corporation, CFT-500D), heat a 1g sample at a heating rate of 6 ° C / min. A load is applied and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

(2) Glass transition point Using a differential scanning calorimeter (DSC210, manufactured by Seiko Denshi Kogyo Co., Ltd.), weigh 0.01 to 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C, and decrease the temperature from that temperature to 10 ° C. A sample cooled to 0 ° C at / min is heated at a heating rate of 10 ° C / min, and the baseline extension line below the maximum endothermic peak temperature and the tangent line indicating the maximum slope from the peak rise to the peak apex The temperature at the intersection with.

3. Methyl ethyl ketone (MEK) insoluble matter derived from resin components
(1) Sample preparation
Using a JIS Z8801 sieve, collect a powder sample that passes through a 22 mesh sieve and does not pass through a 30 mesh sieve. When the sample is a lump or the like, it is pulverized using a commercially available hammer or coffee mill and sieved as a powder.

(2) Sample dissolution
2-1. Weigh 2.000 g of sample in a glass bottle (Made by Yoyo Glass Co., Ltd., M-140), add 95 g of MEK, and attach the inner and outer lids.
2-2. Stir for 5 hours in a ball mill (peripheral speed: 200 mm / sec).
2-3. Leave for 10 hours.

(3) Filtration
3-1. Prepare a glass filter (opening standard 11G-3) attached to a pre-weighed (thousandth of a gram) eggplant flask (weight A (g)). A rubber stopper that can be decompressed is used to seal the glass filter.
3-2. Absorb 20 ml from the supernatant of the lysate that has been allowed to stand for 10 hours in 2-3 with a mespiped, and filter under reduced pressure using the glass filter prepared in 3-1. The supernatant is 2 cm below the liquid level. The degree of vacuum in the eggplant flask before filtering the solution is adjusted to 40 kPa.
3-3. Absorb 20 ml of unused MEK with mespiped and filter the soluble matter adhering to the glass filter under reduced pressure.

(4) Drying
4-1. Remove MEK from the eggplant flask with an evaporator.
Water bath temperature: 70 ℃
Eggplant flask rotation speed: 200r / min
Decompression degree in eggplant flask during MEK removal: Adjust to 40-20 kPa Time: 10 minutes
4-2. After drying at 50 ° C. and 0.13 kPa for 12 hours, weigh the eggplant flask B (g).

(5) Calculation of MEK insoluble matter in the sample
5-1. Calculate MEK soluble content X (g) dissolved in 20 ml of MEK.
X = BA
5-2. MEK soluble content Y (g) dissolved in 95 g of MEK is calculated with the specific gravity of MEK being 0.805.
Y = X × 95 / (20 × 0.805)
5-3. Calculate the soluble content Z ′ (% by weight) per 1 g of the sample.
Z '= Y / 2x100
5-4. MEK insoluble matter (wt%) in the sample Z = 100-Z '
Note that the MEK insoluble content (% by weight) is the average of three measurements.

(6) Calculation of MEK insoluble content derived from resin component in sample The theoretical wax amount W (% by weight) contained in the sample is subtracted from MEK insoluble content Z in the sample. The theoretical wax amount W is a ratio (parts by weight) of the wax with respect to 100 parts by weight of the total amount of all raw material monomers of the resin as a sample.
MEK insoluble matter derived from resin component in sample = Z-W

4). Melting point of wax Using a differential scanning calorimeter (DSC210, manufactured by Seiko Denshi Kogyo Co., Ltd.), the sample was heated to 200 ° C and cooled to 0 ° C at a temperature decrease rate of 10 ° C / min. The maximum peak temperature of heat of fusion is taken as the melting point.

5. Dispersion particle size of primary particles (1) Measuring device: Laser diffraction type particle size measuring machine (Horiba, LA-920)
(2) Measurement conditions: Distilled water is added to the measurement cell, and the volume-median particle size (D ₅₀ ) is measured at a concentration at which the absorbance is 0.6 to 0.9.

6). Toner particle size (1) Preparation of dispersion: Disperse (Emulgen 109P (manufactured by Kao, polyoxyethylene lauryl ether, HLB: 13.6) 5% by weight aqueous solution) add 10 mg of measurement sample to an ultrasonic disperser. Disperse for 1 minute, and then add 25 ml of electrolyte (Isoton II (manufactured by Beckman Coulter)) and further disperse for 1 minute with an ultrasonic disperser to obtain a dispersion.
(2) Measuring device: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
(3) Measurement conditions: 100 ml of electrolyte solution and dispersion liquid were added to a beaker, and the volume-median particle size (D ₅₀ ) of 30,000 particles at a concentration at which the particle size of 30,000 particles could be measured in 20 seconds. Ask for.

Resin production example 1
The raw material monomer of polyester except for trimellitic anhydride shown in Table 1, the wax and the esterification catalyst were put into a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring bar, a flow-down condenser and a nitrogen inlet tube. In a mantle heater, with stirring at a temperature of 150 ° C. in a nitrogen atmosphere, a mixture of the vinyl-based resin raw material monomer, both reactive monomers and the polymerization initiator shown in Table 1 was dropped from the dropping funnel over 1.5 hours. After dropping, the mixture was aged for 1 hour while maintaining at 150 ° C., and further heated to 230 ° C. at a rate of 20 ° C./hr for further reaction. Then, after reacting at 230 ° C. and normal pressure (101.3 kPa) for 6 hours, vacuum reaction was performed at 8 kPa for 1 hour. After cooling to 210 ° C., trimellitic anhydride shown in Table 1 was added, and a vacuum reaction was performed at normal pressure (101.3 kPa) for 1 hour and at 8 kPa for 1 hour. The degree of polymerization was monitored from the softening point according to ASTM E28-67. When the softening point reached a predetermined temperature, the reaction was terminated to obtain a wax-added hybrid resin (resin A).

Resin production example 2
Four 5 liters equipped with a thermometer, a stainless steel stirring rod, a flow-down condenser, and a nitrogen introduction tube, with the raw material monomers of polyester except for trimellitic anhydride shown in Table 1, amphoteric monomers, wax and esterification catalyst. The mixture of the raw material monomer of vinyl resin and the polymerization initiator shown in Table 1 was dropped from a dropping funnel over 1.5 hours while stirring in a mantle heater at a temperature of 150 ° C. in a mantle heater. After dropping, the mixture was aged for 1 hour while maintaining at 150 ° C., and further heated to 230 ° C. at a rate of 20 ° C./hr for further reaction. Then, after reacting at 230 ° C. and normal pressure (101.3 kPa) for 6 hours, vacuum reaction was performed at 8 kPa for 1 hour. After cooling to 210 ° C., trimellitic anhydride shown in Table 1 was added, and a vacuum reaction was performed at normal pressure (101.3 kPa) for 1 hour and at 8 kPa for 1 hour. The degree of polymerization was monitored from the softening point according to ASTM E28-67. When the softening point reached a predetermined temperature, the reaction was terminated to obtain a wax-added hybrid resin (resins B and C).

Resin production example 3
The raw material monomer of polyester except for trimellitic anhydride shown in Table 1, the wax and the esterification catalyst were put into a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring bar, a flow-down condenser and a nitrogen inlet tube. While stirring in a mantle heater at a temperature of 150 ° C. in a nitrogen atmosphere, a mixture of a vinyl resin raw material monomer and a polymerization initiator shown in Table 1 was dropped from a dropping funnel over 1.5 hours. After dropping, the mixture was aged for 1 hour while maintaining at 150 ° C., and further heated to 230 ° C. at a rate of 20 ° C./hr for further reaction. Then, after reacting at 230 ° C. and normal pressure (101.3 kPa) for 6 hours, vacuum reaction was performed at 8 kPa for 1 hour. After cooling to 210 ° C., trimellitic anhydride shown in Table 1 was added, and a vacuum reaction was performed at normal pressure (101.3 kPa) for 1 hour and at 8 kPa for 1 hour. The degree of polymerization was monitored from the softening point according to ASTM E28-67. When the softening point reached a predetermined temperature, the reaction was terminated to obtain a wax-added composite resin (resin D).

Resin production example 4
The polyester raw material monomer, amphoteric monomer, wax and esterification catalyst shown in Table 1 were placed in a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring bar, a flow-down condenser and a nitrogen inlet tube, and nitrogen was added. The reaction was carried out in a mantle heater in an atmosphere at 230 ° C. and normal pressure (101.3 kPa) for 8 hours, and further at 8 kPa for 1 hour. Thereafter, the mixture was cooled to 150 ° C. and stirred at that temperature, and a mixture of the vinyl resin raw material monomer and the polymerization initiator shown in Table 1 was dropped from the dropping funnel over 2 hours. Thereafter, the mixture was aged for 1 hour while being maintained at 150 ° C., and heated to 230 ° C. at a pace of 20 ° C./hr to cause a vacuum reaction. The degree of polymerization was monitored from the softening point according to ASTM E28-67. When the softening point reached a predetermined temperature, the reaction was terminated to obtain a wax-added hybrid resin (Resin E).

Resin production example 5
The raw material monomer of polyester except for trimellitic anhydride shown in Table 1, the wax and the esterification catalyst were put into a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring bar, a flow-down condenser and a nitrogen inlet tube. The reaction was carried out in a mantle heater in a nitrogen atmosphere at 230 ° C. and normal pressure (101.3 kPa) for 8 hours, and further at 8 kPa for 1 hour. After cooling to 210 ° C., trimellitic anhydride shown in Table 1 was added and reacted. The degree of polymerization was monitored from the softening point according to ASTM E28-67, and when the softening point reached a predetermined temperature, the reaction was terminated to obtain a polyester (resin F) to which wax was internally added.

Resin production example 6
850 g of xylene was placed in a 2 liter glass four-necked flask equipped with a thermometer, a stainless steel stir bar, a falling condenser and a nitrogen inlet tube, and the temperature was raised to 150 ° C. after nitrogen substitution. A mixture of a vinyl resin raw material monomer, an amphoteric monomer and a polymerization initiator shown in Table 1 was added dropwise from a dropping funnel over 4 hours and aged at 150 ° C. for 5 hours. Thereafter, the temperature was raised to 200 ° C., and xylene was distilled off under reduced pressure to obtain a styrene acrylic resin (resin G).

Example 1
200 g of resin A and 100 g of nonionic surfactant (polyoxyethylene lauryl ether (EO = 9 mol addition), cloud point: 98 ° C., HLB: 15.3) in a 5 liter stainless steel container with a Kai-type stirrer The mixture was melted at 170 ° C. with stirring of / min. The contents were stabilized at 95 ° C, 3 ° C lower than the cloud point of the nonionic surfactant, and sodium hydroxide aqueous solution (concentration: 5% by weight) 75.5 as a neutralizer under stirring at 200r / min with a chi-type stirrer g was added dropwise. Subsequently, deionized water was added dropwise at 6 g / min with stirring at 300 r / min with a Kai-type stirrer, and a total of 1624.5 g was added. During this time, the system temperature was maintained at 95 ° C., and a resin dispersion containing finely divided resin was obtained through a 200 mesh (mesh: 105 μm) wire mesh. The volume median particle size (D ₅₀ ) of the resin particles (primary particles) in the obtained resin dispersion was 0.45 μm, the solid concentration was 12.0% by weight, and no resin component remained on the wire mesh.

  400 g of the obtained resin dispersion (concentration: 12.3 wt%), 40 g of cyan pigment aqueous dispersion (concentration: 5 wt%) and paraffin wax (HNP-9, manufactured by Nippon Seiwa Co., Ltd., melting point: 78 ° C.) 7 g (concentration: 35 wt%, nonionic surfactant: Emulgen 108 (manufactured by Kao Corporation) 5 wt%, wax dispersion diameter (volume median particle size): 0.30 μm) The mixture was mixed at room temperature in a liter container.

  Next, an aqueous solution corresponding to 1 g of calcium chloride is added to this mixture as a flocculant, adjusted to pH = 7 with an aqueous sodium carbonate solution (concentration: 10% by weight), and then at a rotational speed of 5000 r / min using a homomixer. Stir at room temperature for 1 hour. As a result, the obtained mixed dispersion was transferred to a 1 liter autoclave, heated to 90 ° C. and stirred at 500 r / min for 6 hours to form aggregated particles.

Thereafter, the temperature was raised to 100 ° C., and the mixture was further stirred for 1 hour to coalesce the aggregated particles, and then colored resin fine particle powder was obtained through a suction filtration step, a washing step and a drying step. The volume median particle size (D ₅₀ ) of the colored fine resin particle powder was 6.9 μm, and the water content was 0.3% by weight.

1.0 part by weight of hydrophobic silica (TS530, manufactured by Wacker Chemie, number average particle size: 8 nm) is added to 100 parts by weight of the obtained colored resin fine particle powder, and the mixture is externally added using a Henschel mixer. Cyan toner was used. The resulting cyan toner had a volume-median particle size (D ₅₀ ) of 6.9 μm.

Example 2
Into a 5 L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen introduction tube, 600 g of methyl ethyl ketone was added, and 200 g of resin B was added and dissolved at room temperature. The resulting solution was neutralized by adding 10 g of triethylamine, and then 2000 g of ion exchange water was added, and then methyl ethyl ketone was distilled off at a temperature of 50 ° C. or lower under reduced pressure at a stirring speed of 250 r / min. A self-dispersing aqueous resin particle dispersion (resin content: 9.6% by weight (in terms of solid content)) was obtained. The volume median particle size (D ₅₀ ) of the polyester particles dispersed in the obtained resin dispersion was 0.3 μm.

  Copper phthalocyanine (manufactured by Dainichi Seika Co., Ltd.) 50 g, nonionic surfactant (Emulgen 150, manufactured by Kao Corporation) 5 g and ion-exchanged water 200 g are mixed, copper phthalocyanine is dissolved, and dispersed using a homogenizer for 10 minutes. Thus, a dispersed colorant dispersion was obtained.

  Paraffin wax (HNP0190, manufactured by Nippon Seiwa Co., Ltd., melting point: 85 ° C) 50g, cationic surfactant (Sanisol B50, manufactured by Kao Corp.) 5g and ion-exchanged water 200g are heated to 95 ° C and homogenizer. Was used to disperse the paraffin wax, followed by dispersion with a pressure discharge type homogenizer to obtain a release agent dispersion in which the paraffin wax was dispersed with an average particle size of 550 nm.

  Mix the charge control agent (Bontron E-84, manufactured by Orient Chemical Co., Ltd.) 50 g, nonionic surfactant (Emulgen 150, manufactured by Kao Corporation) and 200 g of ion-exchanged water, use glass beads, sand grinder Was used for dispersion for 10 minutes to prepare a charge control agent dispersion in which the charge control agent was dispersed with an average particle size of 500 nm, and coarse particles remained in the dispersion.

490 g of the obtained resin particle dispersion, 20 g of the colorant dispersion, 15 g of the release agent dispersion, 7 g of the charge control agent dispersion and 2 g of the cationic surfactant (Sanisol B50, manufactured by Kao Corporation) After mixing and dispersing in a stainless steel flask using a homogenizer, the flask was heated to 48 ° C. while stirring in the oil bath for heating. Furthermore, after maintaining at 48 ° C. for 1 hour, it was confirmed that aggregated particles having a volume median particle size (D ₅₀ ) of 7.0 μm were formed.

After adding 3 g of an anionic surfactant (Perex SS-L, manufactured by Kao Corporation) to the aggregated particle dispersion in which the aggregated particles are formed, a reflux tube is attached to the stainless steel flask and stirring is continued. While heating to 80 ° C. at a rate of 5 ° C./min and holding for 5 hours, the aggregated particles were coalesced and fused. Thereafter, the mixture was cooled, the fused particles were filtered, washed thoroughly with ion-exchanged water, and then dried, whereby the volume median particle size (D ₅₀ ) of the obtained colored resin fine particle powder was 7.1 μm.

1.0 part by weight of hydrophobic silica (TS530, manufactured by Wacker Chemie, number average particle size: 8 nm) is added to 100 parts by weight of the obtained colored resin fine particle powder, and the mixture is externally added using a Henschel mixer. Cyan toner was used. The resulting cyan toner had a volume-median particle size (D ₅₀ ) of 7.1 μm.

Example 3
Resin C 100 parts by weight, yellow colorant (Pariotol D1155, manufactured by BASF) 4.0 parts by weight, charge control agent (Bontron E-84, manufactured by Hodogaya Chemical Co., Ltd.) and paraffin wax (HNP-9, Nippon Seiki) 4 parts by weight of Wax Co., Ltd., melting point: 78 ° C.) were premixed with a Henschel mixer, melt-kneaded with an open roll kneader, cooled and pulverized to obtain a 1 mm chip product of the kneaded product. .

200 g of the obtained kneaded product and 100 g of nonionic surfactant (polyoxyethylene lauryl ether (EO = 9 mol addition), cloud point: 98 ° C., HLB: 15.3) in a 5 liter stainless steel container The mixture was melted at 170 ° C. with stirring at 200 r / min. Stabilize the contents at 95 ° C, 3 ° C lower than the cloud point of the nonionic surfactant, and add sodium hydroxide aqueous solution (concentration: 5% by weight) as a neutralizing agent while stirring at 200r / min with a chi-type stirrer. 75.5 g was added dropwise. Subsequently, deionized water was added dropwise at 6 g / min with stirring at 300 r / min with a Kai-type stirrer, and a total of 1624.5 g was added. During this time, the system temperature was maintained at 95 ° C., and a resin dispersion containing finely divided resin was obtained through a 200 mesh (mesh: 105 μm) wire mesh. The volume median particle size (D ₅₀ ) of the resin particles in the obtained resin dispersion was 0.45 μm, the solid concentration was 12.0% by weight, and no resin component remained on the wire mesh.

  Next, an aqueous solution corresponding to 1 g of calcium chloride is added to this mixture as a flocculant, adjusted to pH = 7 with an aqueous sodium carbonate solution (concentration: 10% by weight), and then at a rotational speed of 5000 r / min using a homomixer. Stir at room temperature for 1 hour. The resulting mixed dispersion was transferred to a 1 liter autoclave, heated to 105 ° C. and stirred at 500 r / min for 6 hours to form aggregated particles.

Thereafter, the temperature was raised to 125 ° C., and the mixture was further stirred for 1 hour to coalesce the aggregated particles, and then colored resin fine particle powder was obtained through a suction filtration step, a washing step, and a drying step. The volume median particle size (D ₅₀ ) of the colored fine resin particle powder was 6.8 μm, and the water content was 0.3% by weight.

1.0 part by weight of hydrophobic silica (TS530, manufactured by Wacker Chemie, number average particle size: 8 nm) is added to 100 parts by weight of the obtained colored resin fine particle powder, and the mixture is externally added using a Henschel mixer. Yellow toner was used. The resulting yellow toner had a volume-median particle size (D ₅₀ ) of 6.8 μm.

Example 4
A cyan toner was obtained in the same manner as in Example 1 except that 100 parts by weight of the resin D was used instead of the resin A. The resulting cyan toner had a volume-median particle size (D ₅₀ ) of 6.9 μm.

Example 5
A cyan toner was obtained in the same manner as in Example 1 except that 100 parts by weight of the resin E was used instead of the resin A. The resulting cyan toner had a volume-median particle size (D ₅₀ ) of 6.8 μm.

Comparative Example 1
A cyan toner was obtained in the same manner as in Example 1 except that 100 parts by weight of the resin F was used instead of the resin A. The resulting cyan toner had a volume-median particle size (D ₅₀ ) of 6.9 μm.

Comparative Example 2
A cyan toner was obtained in the same manner as in Example 1 except that 70 parts by weight of resin F and 30 parts by weight of resin G were used instead of resin A. The resulting cyan toner had a volume-median particle size (D ₅₀ ) of 6.8 μm.

Test Example 1 [Preservation]
4 g of each toner obtained in the example was left for 72 hours in an environment of a temperature of 55 ° C. and a humidity of 60%. After standing, the degree of toner aggregation occurrence was visually observed, and storage stability was evaluated according to the following evaluation criteria. The results are shown in Table 2.

〔Evaluation criteria〕
A: No aggregation is observed even after 72 hours.
○: Aggregation is hardly observed even after 72 hours.
Δ: Aggregation is not observed after 48 hours, but aggregation is observed after 72 hours.
X: Aggregation is already observed after 48 hours.

Test Example 2 [Low-temperature fixability and offset resistance]
The toner is mounted on the printer “Page Presto N-4” (Casio Computer Co., Ltd., fixing: contact fixing method, developing method: non-magnetic one-component developing method, developing roll diameter: 2.3 cm), and the toner adhesion amount is 0.6 mg / An unfixed image was obtained by adjusting to cm ² . The fixing machine (fixing speed: 300 mm / s) was improved so that the fixing machine of the contact fixing type copier `` AR-505 '' (manufactured by Sharp Corporation) can be fixed outside the device. The fixing roll was fixed by fixing the unfixed image while increasing the temperature of the fixing roll from 100 ° C. to 240 ° C. by 10 ° C.

  The image obtained at each fixing temperature was pasted with `` UNICEF Cellophane '' (Mitsubishi Pencil Co., Ltd., width 18 mm, JISZ-1522), passed through the fixing roll of the fixing machine set to 30 ° C., and then the tape was applied. The optical reflection density before and after peeling and tape peeling was measured using a reflection densitometer “RD-915” (manufactured by Macbeth). The fixing roller temperature at which the ratio between the two (after peeling / before peeling) first exceeds 95% was set as the minimum fixing temperature, and the low-temperature fixing property was evaluated according to the following evaluation criteria. Also, the hot offset occurrence temperature was confirmed at the same time, and the offset resistance was evaluated according to the following evaluation criteria. The results are shown in Table 2.

[Evaluation criteria for low-temperature fixability]
A: Minimum fixing temperature is less than 160 ° C. ○: Minimum fixing temperature is 160 ° C. or more and less than 170 ° C. Δ: Minimum fixing temperature is 170 ° C. or more and less than 180 ° C. ×: Minimum fixing temperature is 180 ° C. or more

[Evaluation criteria for offset resistance]
◎: Hot offset generation temperature is 240 ° C or higher ○: Hot offset generation temperature is 230 ° C or higher and lower than 240 ° C △: Hot offset generation temperature is 190 ° C or higher and lower than 230 ° C ×: Hot offset generation temperature is lower than 190 ° C

  From the above results, it can be seen that the toners of the examples have better storage stability, offset resistance, and low-temperature fixability than the comparative examples. Among them, the toners of Examples 1 to 3 containing the wax-added hybrid resin in which both reactive monomers are used in appropriate amounts are compatible with each other at high levels of storage stability, offset resistance, and low-temperature fixability.

  The toner for electrophotography of the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (9)

A method for producing an electrophotographic toner comprising a step of forming a raw material containing a binder resin in an aqueous medium , wherein the binder resin comprises a polyolefin wax, a paraffin wax, and a Fischer-Tropsch wax. A composite resin obtained by condensation polymerization of a raw material monomer of a condensation polymerization resin and addition polymerization of a raw material monomer of an addition polymerization resin in the presence of at least one wax selected from the group consisting of The method for producing a toner for electrophotography, wherein the raw material monomer of the condensation polymerization resin is a raw material monomer of polyester, and the raw material monomer of the addition polymerization resin contains styrene.   2. The method for producing an electrophotographic toner according to claim 1, wherein the amount of the wax is 0.5 to 25 parts by weight with respect to 100 parts by weight of the total amount of the raw material monomers of the condensation polymerization resin and the addition polymerization resin.   The weight ratio of the raw material monomer of the condensation polymerization resin and the raw material monomer of the addition polymerization resin (the raw material monomer of the condensation polymerization resin / the raw material monomer of the addition polymerization resin) is 50/50 to 95/5. 3. A method for producing an electrophotographic toner according to 2.   A resin obtained by mixing a wax, a raw material monomer of a condensation polymerization resin, and a raw material monomer of an addition polymerization resin in advance, and performing the condensation polymerization reaction and the addition polymerization reaction in the same reaction vessel in parallel. The method for producing an electrophotographic toner according to claim 1.   The composite resin is a resin obtained by polycondensation and addition polymerization of a compound (both reactive monomers) that can react with both the raw material monomer of the condensation polymerization resin and the raw material monomer of the addition polymerization resin. The method for producing an electrophotographic toner according to any one of -4.   6. The method for producing an electrophotographic toner according to claim 5, wherein the both reactive monomers are at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid and derivatives of these carboxylic acids. The both reactive monomers are carboxylic acid or a derivative thereof, and the amount of both reactive monomers used is the formula (A):
0.10 <X / Y <0.50 (A)
(In the formula, X is the molar fraction (mol%) of both reactive monomers in the carboxylic acid component that is the raw material monomer of the condensation polymerization resin, and Y is It is the value of the weight fraction (wt%) of the raw material monomer of the addition polymerization resin in the total amount of the raw material monomer of the resin x the number of functional groups in one molecule of both reactive monomers]
The method for producing an electrophotographic toner according to claim 5 or 6 satisfying the above.   The method for producing an electrophotographic toner according to claim 1, wherein the acid value of the composite resin is 5 to 30 mg KOH / g.   An electrophotographic toner obtained by the production method according to claim 1.