JP2017227802A - Electrostatic charge image developing carrier, electrostatic charge image developing carrier manufacturing method, and two-component developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing carrier that maintains an excellent charge property even after being used over a long time, and the adhesion to output images is suppressed.SOLUTION: An electrostatic charge image developing carrier has a resin coating layer on a core material particle surface. The resin coating layer includes resin that contains: a constituent unit derived from an alicyclic alkyl (meta) acrylic acid ester monomer; a constituent unit derived from a polymerizable monomer having a reactive functional group of at least one kind to be selected from a group composed of a carboxyl group, an amino group, a hydroxyl group and an epoxy group; and a structure derived from a cross-linker forming the reactive functional group and a crosslink structure. The electrostatic charge image developing carrier is configured such that a crosslink degree gradually increases from a carrier surface toward a boundary face between the core material particle and the resin coating layer.SELECTED DRAWING: None

Description

  In recent years, electrophotographic copying machines and printers have been increased in printing speed, and two-component developers advantageous for high-speed development have become mainstream as developers used for them. The two-component developer is composed of a magnetic powder called a carrier for electrostatic charge development (hereinafter also simply referred to as “carrier”) and a toner for electrostatic charge development (hereinafter also simply referred to as “toner”). Yes. The two-component developer is advantageous for high-speed development because the toner and carrier can be mechanically agitated to quickly give the toner a desired charge amount. The functions required of the carrier include proper triboelectric chargeability to the toner, fluidity, developability, and high durability that can withstand long-term use. In order to improve these functions, a type of carrier called a resin-coated carrier formed by coating a resin on the surface of core material particles made of a ferromagnetic metal or its oxide is widely used.

  When the degree of cross-linking of the carrier coating resin is increased, the wear resistance of the resin is improved and the coating resin is less likely to be worn (Patent Documents 1 and 2). However, if the carrier is stirred for a long time in the developing machine, the toner resin will be spent on the carrier, or the external additive may be transferred to the carrier and buried in the carrier coating resin. The performance is deteriorated, and the image density is lowered, the image is fogged, and the toner is contaminated with the toner.

  Therefore, as a countermeasure against carrier contamination, Patent Document 3 describes an example in which an alicyclic methacrylate ester or the like is used as a coating resin, the coating resin is abraded, and toner spent on the carrier surface and external additives are scraped off by toner. ing. In Patent Document 4, development is performed over a long period of time by adopting a trickle development system in which deteriorated developer is gradually discharged from the developing device and carrier and toner are replenished according to the amount of discharged developer. An example in which the deterioration of the agent is suppressed and the deterioration of the image quality is reduced is described. However, when the developer is used for a long time on a high-speed machine, the core material particles of the carrier are exposed due to wear of the coating resin, and the carrier may adhere to the output image due to excessive low resistance.

  Therefore, Patent Document 5 discloses a carrier for developing an electrostatic charge image having a resin coating layer composed of two or more resins, in which the lowermost layer is a crosslinked resin and the uppermost layer is a non-crosslinked resin. Yes.

JP, 2006-018046, A Japanese Patent No. 5762227 Japanese Patent No. 3691085 Japanese Patent No. 5521980 JP 2007-322613 A

  However, according to studies by the present inventors, the electrostatic charge image developing carrier according to Patent Document 5 has insufficient chargeability and carrier adhesion resistance (suppression of carrier adhesion to an output image) after long-term use. It turned out to be.

  Accordingly, the present invention has been made in view of the above problems, and an electrostatic charge image developing carrier that maintains good chargeability even after long-term use and suppresses adhesion to an output image. The purpose is to provide.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have developed an electrostatic charge image developing carrier having a resin coating layer on the surface of the core particle, and the resin coating layer has an alicyclic ( A structural unit derived from a polymerizable monomer having a structural unit derived from a (meth) acrylate monomer and at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group, a hydroxyl group and an epoxy group And a structure derived from a crosslinking agent that forms a crosslinked structure with the reactive functional group, and the degree of crosslinking from the surface of the carrier toward the interface between the core particle and the resin coating layer. It has been found that the above problems can be solved by the gradually increasing carrier for developing an electrostatic image, and the present invention has been completed.

  According to the present invention, it is possible to obtain a carrier for developing an electrostatic image that maintains good chargeability even after being used for a long time and suppresses adhesion to an output image.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited only to the following embodiment.

  In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, measurement of operation and physical properties is performed under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH. Moreover, in this specification, "(meth) acryl" refers to methacryl and / or acryl.

<Carrier for developing electrostatic image>
The electrostatic charge image developing carrier according to the present invention (hereinafter also simply referred to as “carrier”) has core particles and a resin coating layer coated on the surface of the core particles. The degree of crosslinking gradually increases from the carrier surface toward the interface between the core material particles and the resin coating layer. The resin coating layer is composed of a structural unit derived from an alicyclic (meth) acrylate monomer (hereinafter also referred to as “monomer A”), a carboxyl group, an amino group, a hydroxyl group, and an epoxy group. A polymerizable monomer having at least one reactive functional group selected from the group (hereinafter also referred to as “monomer B”), and a cross-linking agent that forms a cross-linked structure with the reactive functional group And having a structure. A carrier having such a configuration maintains good chargeability even after long-term use and suppresses adhesion to an output image. The mechanism by which such effects are achieved is not completely clear, but the following mechanism has been estimated.

  In the initial stage of durability, since the resin coating layer is thick, the volume resistance of the carrier is high, and external additives are buried and toner spent (fixed) tends to occur. Thus, by using an alicyclic (meth) acrylic acid ester monomer that provides appropriate film strength (easy to wear), and reducing the degree of crosslinking in the vicinity of the carrier surface of the resin coating layer, the resin coating layer Is subject to wear. Thereby, the external additive and the toner adhering to the resin coating layer are removed, and the carrier surface is refreshed. Therefore, good chargeability can be maintained even after long-term use.

  On the other hand, since the resin coating layer is thin at the end of durability, the volume resistance of the carrier is low, and the carrier surface is hardly contaminated by external additives and toner as described above. May be exposed. Therefore, by increasing the degree of crosslinking in the vicinity of the core particles of the resin coating layer, the resin coating layer is less likely to be worn. Thereby, exposure of core material particles is suppressed and excessive resistance reduction of the carrier is suppressed. Therefore, adhesion of the carrier to the output image is suppressed, and a decrease in charging property due to image fogging or toner contamination due to toner is suppressed.

  In addition, since the carrier according to Patent Document 5 uses different types of resins for the upper layer and the lower layer, peeling tends to occur at the boundary portion, suggesting the possibility that the charging performance has changed. In addition, since the lower layer is exposed due to peeling, the core particles due to wear of the lower layer are exposed and carrier adhesion is likely to occur. On the other hand, since the carrier according to the present invention has a resin coating layer formed of the resin having the above composition, even when the resin coating layer has a multilayer structure, peeling at the boundary portion is unlikely to occur, and the charging property The change of is suppressed. Therefore, good chargeability can be maintained even under long-term use. Moreover, since exposure of the lower layer due to peeling is suppressed, it is possible to further suppress wear of the lower layer and, consequently, exposure of the core material particles. Therefore, the carrier according to the present invention can further improve the carrier adhesion resistance even when used for a long time.

  The present invention is not limited to the above mechanism.

  In the resin coating layer of the carrier according to the present invention, the degree of crosslinking gradually increases from the carrier surface toward the interface between the core material particles and the resin coating layer. The resin coating layer may have a single layer structure or a multilayer structure having two or more layers. In the case of a multilayer structure, by providing a difference in the degree of crosslinking between the layers, a resin coating layer in which the degree of crosslinking gradually increases in the film thickness direction can be obtained. That is, one embodiment of the carrier according to the present invention has the resin coating layer 1 having a crosslinked structure on the surface of the core material particles, and the degree of crosslinking compared to the resin coating layer 1 outside the resin coating layer 1. It has a low resin coating layer 2.

  Hereinafter, each component used for formation of a resin coating layer is demonstrated.

[Components of resin coating layer]
(Monomer A: Alicyclic (meth) acrylic acid ester monomer)
The alicyclic (meth) acrylic acid ester monomer (monomer A) is a monomer in which the alcohol-derived site of the (meth) acrylic acid ester monomer contains a cycloalkyl group.

  As the monomer A, those having a cycloalkyl ring having 3 to 7 carbon atoms are preferable. For example, cyclopropyl methacrylate, cyclobutyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, acrylic Examples include cyclopropyl acid, cyclobutyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, and cycloheptyl acrylate. Among these, from the viewpoint of mechanical strength and environmental stability of the charge amount, it is preferable to include cyclohexyl (meth) acrylate, and it is particularly preferable to include cyclohexyl methacrylate. These may be used alone or in combination of two or more.

  The content of the structural unit derived from the monomer A in the resin coating layer is determined based on the monomer constituting the resin (“monomer A”, “monomer B”, and “other monomers” described later). When the total amount of the constituent units derived from the following is 100% by mass, it is preferably 10 to 99% by mass. In particular, when the resin coating layer has a two-layer structure, the content in the lower layer is preferably 60 to 95% by mass, more preferably 70 to 90% by mass, and even more preferably 75 to 85% by mass. And particularly preferably 78 to 83% by mass. Further, the content in the upper layer is preferably 10 to 98% by mass, more preferably 30 to 97% by mass, still more preferably 40 to 96% by mass, and particularly preferably 50 to 95% by mass. It is. If it is such a range, the effect of this invention will become still more remarkable. Further, from the viewpoint of further improving the effect of the present invention, the content in the upper layer is preferably larger than the content in the lower layer. In addition, the said content is substantially the same as the ratio of the compounding quantity of the monomer A with respect to the monomer total quantity at the time of manufacturing resin.

(Monomer B: polymerizable monomer having at least one reactive functional group selected from the group consisting of carboxyl group, amino group, hydroxyl group and epoxy group)
The polymerizable monomer (monomer B) having at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group, a hydroxyl group and an epoxy group is preferably a vinyl monomer. More preferably, it is a (meth) acrylic monomer, and from the viewpoint of improving wear resistance, (meth) acrylic acid or a chain or branched (meth) acrylic acid ester having the reactive functional group is used. Even more preferably.

  Examples of the polymerizable monomer having a carboxy group include acrylic acid, methacrylic acid, 3-butenoic acid, 2-butenoic acid, 4-pentenoic acid, 3-pentenoic acid, 5-hexenoic acid, 4-hexenoic acid, 5- Examples include heptenoic acid. These may be used alone or in combination of two or more.

  Examples of the polymerizable monomer having an amino group include 2-ethynylaniline, 3-ethynylaniline, 4-ethynylaniline, 2-ethynylaniline, 3-ethynylaniline, 4-ethynylaniline, 1-hexene-3- Amine, 1-hexene-4-amine, 1-hexene-5-amine, 1-hexene-6-amine, 2-hexene-4-amine, 2-hexene-5-amine, 2-hexene-6-amine, 4-ethenyl-1,6-heptadiene-4-amine, 2-ethenyl-N-methyl-3-buten-1-amine, 1-ethenylcyclohexane-1-amine, 3- (4-ethenylphenyl) propane Examples include -1-amine. These may be used alone or in combination of two or more.

  Examples of the polymerizable monomer having a hydroxyl group include hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2 -Hydroxybutyl methacrylate, 2-hydroxypropyl-2-propenoate, 4-hydroxybutyl-2-propenoate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 1-hydroxy-2-propanyl-2-methyl-2-propenoate 2-hydroxyethyl-2-methyl-2-propenoate, ethyl 2- (hydroxymethyl) -2-propenoate, hydroxyphenyl methacrylate Over DOO, monomers such as 2-hydroxy-3-phenoxypropyl acrylate. These may be used alone or in combination of two or more.

  Examples of the polymerizable monomer having an epoxy group include glycidyl acrylate, glycidyl methacrylate, 2-ethynyloxirane, 2-propenyl-2-oxirane, 2-butenyl-3-oxirane, 2-hexynyl-5-oxirane, 2 -(4-Methyl-3-pentenyl) oxirane, 2,3-bis (ethynyl) oxirane, 2- (2-ethenoxyethoxymethyl) oxirane, 2- (2-propenoxymethyl) oxirane, 2- (ethenoxymethyl) ) Oxirane, 2-ethenyl-2-methyloxirane, 2-methyl-3-propenyl-oxirane, 2-methyl-2- (2-methyl-2-propenoxymethyl) oxirane, 2-ethenyl-3- Pentyloxirane, 2-ethynyl-3-methyloxirane, 2- (3-methyl-2-butene Xymethyl) oxirane, 2-methyl-2-pentenyl-4-oxirane, 2-butyl-3-ethenyloxirane, 2-methyl-3- (2-propenyl) oxirane, 2,2-dimethyl-3- ( 4-pentenyl) oxirane, 2-methyl-3- (2-propenoxymethyl) oxirane, 2-methyl-2- (4-methyl-3-pentenyl) oxirane, 2-ethenyl-2-phenyloxirane, 2- Examples include ethenyl-3-phenyl-oxirane, 2- (4-ethenylphenyl) oxirane and the like. These may be used alone or in combination of two or more.

  The content of the structural unit derived from the monomer B in the resin coating layer is preferably 1 to 95% by mass when the total amount of the structural unit derived from the monomer constituting the resin is 100% by mass. In particular, when the resin coating layer has a two-layer structure, the content in the lower layer is preferably 5 to 40% by mass, and more preferably 10 to 30% by mass. Moreover, the said content in an upper layer becomes like this. Preferably it is 0.1-20 mass%, More preferably, it is 0.5-15 mass%, More preferably, it is 0.5-10 mass%. If it is such a range, the effect of this invention will become still more remarkable. Further, from the viewpoint of further improving the effect of the present invention, the content in the upper layer is preferably smaller than the content in the lower layer. In addition, the said content is substantially the same as the ratio of the compounding quantity of the monomer B with respect to the monomer total amount at the time of manufacturing resin.

(Other monomers)
The resin coating layer may contain a structural unit derived from a monomer other than the monomer A and the monomer B (hereinafter also referred to as “other monomer”) as necessary. .

  Specific examples of other monomers include chain or branched (meth) acrylic esters such as methyl (meth) acrylate and t-butyl (meth) acrylate, aminoalkyl esters of (meth) acrylic acid, etc. Examples include (meth) acrylic monomers, vinyl monomers such as styrene, vinyl acetate, and vinyl chloride. Among these, from the viewpoint of improving wearability and chargeability, it is preferable to include methyl (meth) acrylate, and it is particularly preferable to include methyl methacrylate. These may be used alone or in combination of two or more.

  The content of structural units derived from other monomers in the resin coating layer is preferably 0 to 20% by mass, when the total amount of structural units derived from monomers constituting the resin is 100% by mass, More preferably, it is 0-10 mass%, More preferably, it is 0-5 mass%. In addition, the said content is substantially the same as the ratio of the compounding quantity of the other monomer with respect to the monomer total quantity at the time of manufacturing resin.

  In addition, when the resin coating layer has a multilayer structure, from the viewpoint of suppressing the occurrence of peeling between layers, if one layer contains a constituent unit derived from another monomer, the other layers are the same. It is preferable to contain the said structural unit.

(Crosslinking agent)
The cross-linking agent used for forming the resin coating layer is not particularly limited as long as it is a polyfunctional compound that can form a cross-linked structure with the reactive functional group of the monomer B. It is at least one selected from the group consisting of a functional isocyanate compound, a polyfunctional carboxylic acid compound, a polyfunctional amine compound, and a carbodiimide compound.

  Examples of polyfunctional epoxy compounds include 2,2-bis (4-hydroxyphenyl) propane diglycidyl ether (bisphenol A diglycidyl ether), ethylene glycol diglycidyl ether, triglycidyl isocyanurate, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, phenol novolac resin type epoxy resin, 1,5-hexadiene diepoxide, 1,4-pentadiene diepoxide, 1,2: 6,7-diepoxyheptane, 1,2,8,9-diepoxynonane, 2,2 ′-(1,6-hexanediyl) bisoxirane, 1,2,7,8-diepoxyoctane, 1,5-diepoxycyclohexane, 1, 2: 3,4-diepoxycyclohex 1,2,5,6-diepoxycyclooctane, limonene dioxide, cis-1,2: 4,5-diepoxy-p-menthane, 1,6-diepoxynaphthalene, triepoxydecane, etc. It is done. These may be used alone or in combination of two or more.

  Examples of polyfunctional isocyanate compounds include isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, triene diisocyanate, polymeric MDI, naphthalene diisocyanate, tetramethylxylylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate methyl ester, hydrogenated xylylene diisocyanate. , Diphenylmethane diisocyanate, methylenebis (4,1-cyclohexylene) = diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, adducts of diisocyanate compounds and polyol compounds such as trimethylolpropane, biurets and isocyanurates of diisocyanate compounds Isocyanate derivatives such as And the like. These may be used alone or in combination of two or more.

  Examples of polyfunctional carboxylic acid compounds include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, terephthalic acid, isophthalic acid, sulfoisophthalic acid, 2,2 -Dipropylpropanedioic acid, 1,1-cyclobutanedicarboxylic acid, cyclopentane-1,3-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 5-methylisophthalic acid, 4-hydroxy Isophthalic acid, 2,3,5,6-tetramethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, 2- (2-carboxylphenyl) benzene acid, biphenyl-3,3'-dicarboxylic acid, biphenyl-3,4 Examples include '-dicarboxylic acid. These may be used alone or in combination of two or more.

  Examples of polyfunctional amine compounds include hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, 2-methyl-1,5-diaminopentane, 3,3-dimethylbutane-1,2-diamine, 4 -Methylpentane-1,2-diamine, 2,2,4,4-tetramethylcyclobutane, 2-methylcyclohexane-1,3-diamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,6 -Diaminotoluene, 3,4-diaminotoluene, 2,3-diaminotoluene, 2,5-dimethylbenzene-1,2-diamine, 3,4-dimethylbenzene-1,2-diamine, 2,6-dimethylbenzene -1,4-diamine, 2,4-dimethylbenzene-1,3-diamine, 3,5-dimethyl-1,2-ben Diamine, 4-ethylbenzene-1,3-diamine, 2,5-dimethylbenzene-1,4-diamine, 4-methoxybenzene-1,3-diamine, 4- (1,1-dimethylethyl) -1,2 Benzenediamine, paraphenylenediamine, orthophenylenediamine, N-isopropyl-1,3-propanediamine, N-hexylethylenediamine, 5-isopropylaminoamylamine, n-butylethylenediamine, N-tertiarybutylbutane-1, 4-diamine, N-ethylhexane-1,6-diamine, n-isobutylethane-1,2-diamine, N-cyclohexyl-1,2-ethanediamine, N1-methylcyclohexane-1,4-diamine, N-methylbenzene-1,2-diamine, N-phenylethylenediamine, -Ethylbenzene-1,2-diamine, N1-methylbenzene-1,3-diamine, 4-amino-N-methylaniline, 2-aminodiphenylamine, 4-aminodiphenylamine, 1-N, 4-dimethylbenzene-1, 2-diamine, N1,5-dimethylbenzene-1,2-diamine, N-isopropyl-benzene-1,2-diamine, N- (3-aminophenyl) -N-phenylamine, N, N′-dimethyltri Methylenediamine, N, N′-diethylbutylenediamine, N, N′-diisopropyl-2,3-butane-diamine, N, N′-diethyl-2-butene-1,4-diamine, N, N′-diisopropyl Ethylenediamine, N-propyl-N′-isopropylethylenediamine, N, N′-dimethylbutane-1,4-diamine, N, N′-diethyl-1,3-propanediamine, N, N′-diethylethylenediamine, (1R, 2R) -1-N, 2-N-dimethylcyclohexane-1,2-diamine, N, N′- Dimethyl-1,2-cyclohexanediamine, 1-N, 4-N-dimethylcyclohexane-1,4-diamine, 1,4-benzenediamine, 1,2,4-triaminobenzene, 2,4,5-tri Aminotoluene, 2,4,6-triaminotoluene, 2,3,4-triaminotoluene, 3,5,6-triaminotoluene, 3-N-methylbenzene-1,2,3-triamine, 2- N-methylbenzene-1,2,3-triamine, 4-N-methylbenzene-1,2,4-triamine, 1-N-methylbenzene-1,2,4-triamine, 3-N-methylbenzene 1,3,5-triamine, 1-N ′, 1-N ″ -diethylpropane-1,1,1-triamine, 4- (3,4-diaminophenyl) benzene-1,2-diamine, 1-N , 1-N, 2-N, 2-N, 3-N, 3-N, 4-N, 4-N-octamethylbutane-1,2,3,4-tetraamine, 4- [3-amino- 4- (methylamino) phenyl] benzene-1,2-diamine and the like. These may be used alone or in combination of two or more.

  Examples of the carbodiimide compound include diisopropylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide, N- [3- (dimethylamino) propyl] -N-ethylcarbodiimide, 1-ethyl-3-tert- Examples include butyl carbodiimide and 1,3-bis (p-tolyl) carbodiimide. These may be used alone or in combination of two or more.

  In the resin coating layer, the content of the structure derived from the cross-linking agent that forms a cross-linked structure with the reactive functional group contained in the monomer B is the total amount of structural units derived from the monomer composing the resin. It is preferable that it is 5-80 mass% when it is set as the mass%. When the resin coating layer has a two-layer structure, the ratio of the content of the upper layer to the content of the lower layer is preferably 0 to 70%, more preferably 5 to 60%. More preferably, it is -50%, and it is especially preferable that it is 25-45%. If it is such a range, the effect of this invention will become still more remarkable. The ratio is the content of the crosslinking agent in the lower layer resin particles when the lower layer and upper layer crosslinking conditions are the same in the resin coating layer forming method described later (method of crosslinking the resin particles containing the crosslinking agent). Is substantially the same as the ratio of the content of the crosslinking agent in the upper layer resin particles to

(Nitrogen, phosphorus, sulfur element)
The resin coating layer preferably contains at least one element selected from the group consisting of nitrogen (N), phosphorus (P), and sulfur (S). Since the N element and the S element function as a charging site, the inclusion of these improves the rising property of charging and secures more effective charging property. Further, by containing the P element, the charging environmental stability is maintained.

  In the resin coating layer, the above-mentioned element can be obtained by using a compound containing the above element as a polymerizable monomer, a crosslinking agent, a polymerization initiator, a chain transfer agent, a surfactant, etc. It can be included. Further, in the step of forming the resin coating layer on the core material particles, additives such as inorganic fine particles and organic fine particles containing the above elements can also be contained in the coating resin.

  As a compound containing N element, said polyfunctional isocyanate compound is mentioned, for example. The N element can be calculated from the element peak area intensity of N1s using an Shimadzu X-ray photoelectron analyzer (ESCA-1000, manufactured by Shimadzu Corporation) with an X-ray output of 10 KV and 30 mA.

  Examples of the compound containing S element include sulfonic acid type surfactants such as sodium dodecyl sulfate, and persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate.

  Examples of the compound containing P element include phosphate type surfactants such as sodium lauryl phosphate.

  P element and S element can be measured using a fluorescent X-ray analyzer “XRF-1700” (manufactured by Shimadzu Corporation). As a specific measuring method, a sample 2g can be pressurized and pelletized, and a qualitative quantitative analysis can be performed under the following conditions to calculate the element amount from the Net intensity value. For measurement, the Kα peak angle of the element to be measured is determined from the 2θ table and used.

X-ray generation part condition / target Rh, tube voltage 40 kV, tube current 95 mA, no filter Spectroscopic condition / slit standard, no attenuator Spectral crystal / Ge (P, S).

(Additive)
The resin coating layer may contain additives such as charge control particles and conductive particles as necessary.

  Examples of charge control particles include strontium titanate, calcium titanate, magnesium oxide, azine compounds, quaternary ammonium salts, triphenylmethane, and the like. The addition amount of the charge control particles is 2 to 40 parts by mass for strontium titanate, calcium titanate or magnesium oxide with respect to 100 parts by mass of the resin, and 0 for azine compounds, quaternary ammonium salts or triphenylmethane. It is preferable that it is 3-10 mass parts.

  Examples of the conductive particles (conductive agent) include carbon black, zinc oxide, tin oxide and the like. The addition amount of the conductive particles is 2 to 40 parts by mass for carbon black, 2 to 150 parts by mass for zinc oxide, and 2 to 200 parts by mass for tin oxide with respect to 100 parts by mass of the resin. It is preferable.

[Core particles]
The carrier particles constituting the carrier of the present invention include core material particles. Examples of the core particles include metal powders such as iron powder and various ferrites. Among these, ferrite is preferable.

  As the ferrite, ferrite containing heavy metals such as copper, zinc, nickel and manganese and light metal ferrite containing alkali metals or alkaline earth metals are preferable.

Ferrite is a compound represented by the formula: (MO) _x (Fe ₂ O ₃ ) _y , and the molar ratio y of Fe ₂ O ₃ constituting the ferrite is preferably 30 to 95 mol%. Within such a range, there are merits that a desired magnetization can be easily obtained and a carrier that hardly causes carrier adhesion can be produced. M in the formula is manganese (Mn), magnesium (Mg), strontium (Sr), calcium (Ca), titanium (Ti), copper (Cu), zinc (Zn), nickel (Ni), aluminum (Al) , Silicon (Si), zirconium (Zr), bismuth (Bi), cobalt (Co), lithium (Li) and the like, and these can be used alone or in combination. Among these, manganese, magnesium, strontium, lithium, copper, and zinc are preferable, and manganese, magnesium, and strontium are more preferable from the viewpoint that the remanent magnetization is low and suitable magnetic characteristics can be obtained.

  As the core particles, commercially available products or synthetic products may be used. Examples of the synthesis method include the following methods.

  First, an appropriate amount of raw materials are weighed, and then pulverized and mixed with a wet media mill, a ball mill, a vibration mill or the like, preferably for 0.5 hours or more, more preferably for 1 to 20 hours. The pulverized product thus obtained is pelletized using a pressure molding machine or the like, and then calcined at a temperature of preferably 700 to 1200 ° C., preferably for 0.5 to 5 hours.

  After pulverizing without using a pressure molding machine, water may be added to form a slurry, and granulated using a spray dryer. After pre-baking, after further pulverizing with a ball mill or vibration mill, etc., water and, if necessary, a dispersant, a binder such as polyvinyl alcohol (PVA), etc. are added to adjust the viscosity and granulate. Done. The firing temperature is preferably 1000 to 1500 ° C., the firing time is preferably 1 to 24 hours, and the oxygen concentration during firing is preferably 0.5 to 5% by volume. is there. When pulverizing after calcination, water may be added and pulverized with a wet ball mill, a wet vibration mill or the like.

  The pulverizer such as the above-mentioned ball mill or vibration mill is not particularly limited, but it is preferable to use fine beads having a particle diameter of 1 cm or less for the medium to be used in order to disperse the raw materials effectively and uniformly. Further, the degree of grinding can be controlled by adjusting the diameter, composition and grinding time of the beads used.

  The fired product thus obtained is pulverized and classified. As a classification method, the particle size is adjusted to a desired particle size using an existing air classification method, mesh filtration method, sedimentation method, or the like.

  Thereafter, if necessary, the surface can be heated at a low temperature to perform an oxide film treatment to adjust the resistance. The oxide film treatment can be performed by heat treatment at, for example, 300 to 700 ° C. using a general rotary electric furnace, batch electric furnace or the like. The thickness of the oxide film formed by this treatment is preferably 0.1 nm to 5 μm. By making the thickness of the oxide film within the above range, the effect of the oxide film layer can be obtained, and it is easy to obtain desired characteristics without becoming too high resistance. If necessary, reduction may be performed before the oxide film treatment. In addition, after classification, low-magnetism products may be further classified by magnetic separation.

  The shape factor (SF-1) of the core material particles is preferably 110 to 140, and more preferably 120 to 130. Within such a range, the coating material can have a thickness distribution. In the portion where the covering material is thin, the core particle having low resistance property reduces the volume resistivity of the carrier, so that electrons easily move and excessive charging under low temperature and low humidity is suppressed. In addition, since the charge can be held in the portion where the covering material is thick, the decrease in the charge amount under high temperature and high humidity is suppressed. That is, within the above range, a carrier with a small environmental difference in charge amount is obtained. Such a carrier can give a constant charge amount to the toner even if the temperature and humidity environment changes.

  The shape factor SF-1 of the core material particles can be adjusted by changing the composition ratio of the raw materials, the degree of pulverization, and the firing conditions (temperature, oxygen concentration, etc.).

  The shape factor (SF-1) of the core particle is a numerical value calculated by the following formula 1.

  In the above formula, “MXLNG” represents the maximum diameter of the core material particles, and “AREA” represents the projected area of the core material particles. Here, the maximum diameter means a width in which the interval between the parallel lines is maximum when the projected image of the core particles on the plane is sandwiched between the two parallel lines. The projected area refers to the area of the projected image on the plane of the core particles. The maximum diameter and projected area of the core material particles are obtained by the following measurement method.

  That is, 100 or more randomly selected core particles are photographed with a scanning electron microscope at a magnification of 150 times, and the photographed images are taken into a scanner and measured using an image processing analyzer LUZEX AP (manufactured by Nireco Corporation). To do. The shape factor of the core material particles is a value calculated as an average value of the shape factors of the respective core material particles calculated by the above formula 1.

  The average particle diameter of the core particles is preferably 15 to 80 μm, and more preferably 20 to 70 μm, as a median diameter (D50) on a volume basis. Within such a range, a sufficient contact area with the toner can be secured, and a high-quality toner image can be stably formed. The median diameter (D50) can be measured by a laser diffraction particle size distribution measuring apparatus “HELOS & RODOS” (manufactured by Sympatec) provided with a wet dispersion device.

The saturation magnetization of the core particles is preferably 1.0 × 10 ^{−4 to} 2.5 × 10 ⁻⁵ Wb · m / kg. By using a carrier having such magnetic characteristics, partial aggregation of the carrier is unlikely to occur. For this reason, the two-component developer is uniformly dispersed on the surface of the developer conveying member, and it is possible to form a uniform and high-definition toner image without density unevenness. Residual magnetization can be reduced by using ferrite. When the residual magnetization is small, the carrier itself has good fluidity, and a two-component developer having a uniform bulk density can be obtained.

[Carrier manufacturing method]
The carrier production method according to the present invention is not particularly limited, but a method is preferred in which a plurality of resin particles having different cross-linking agent contents are prepared, and these are adhered to the core material particles in the descending order of the cross-linking agent content to be cross-linked. . By producing by such a method, it is possible to obtain a carrier having a resin coating layer whose degree of crosslinking gradually increases from the carrier surface toward the interface between the core material particles and the resin coating layer. At this time, if the crosslinking conditions (for example, the crosslinking temperature and the crosslinking time) are the same, the amount of the crosslinked structure formed is assumed to be proportional to the content of the crosslinking agent in the resin particles.

  That is, in one embodiment of the carrier manufacturing method according to the present invention, after the resin particles 1 are adhered to the surface of the core material particles, the resin particles 1 are crosslinked by heating to form the resin coating layer 1, and the resin The resin particles 2 are adhered to the surface of the coating layer 1 and the resin particles 2 are crosslinked by heating to form the resin coating layer 2. The resin particles 1 and the resin particles 2 are alicyclic (meta ) A polymerizable monomer having a structural unit derived from an acrylate monomer (monomer A) and at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group, a hydroxyl group and an epoxy group A resin containing a structural unit derived from the body (monomer B), and a crosslinking agent that forms a crosslinked structure with the reactive functional group, wherein the resin particle 1 is the crosslinking agent compared to the resin particle 2 High content, made It is a method.

(Production of resin particles)
The resin particles used for forming the resin coating layer are not particularly limited, but preferably include the above-described crosslinking agent. At this time, in order to prevent the cross-linking reaction from proceeding between the cross-linking agent and the structural unit derived from the monomer B before adhering to the core material particles, both components are formed in different compartments (for example, cores). Part and shell part). When such resin particles are used, the resin particles are melted by heating to a temperature higher than the glass transition temperature, and both components present in different compartments are mixed to proceed with a crosslinking reaction. Thereby, the resin coating layer which has a crosslinked structure can be obtained. In addition, such a core-shell structure can be applied to a wide range of crosslinking agents because the conditions during the production process are not limited.

  Hereinafter, as an example, a method for producing core-shell type resin particles in which a crosslinking agent is contained in the core part and a structural unit derived from the monomer B is contained in the shell part will be described. The method for producing the resin particles is not limited to this.

≪Preparation of resin particle core≫
The resin particle core can be produced by homopolymerizing or copolymerizing monomers other than the monomer B in the presence of the crosslinking agent.

  The production method of the resin particle core is not particularly limited, and a conventionally known polymerization method such as a pulverization method, an emulsion dispersion method, a suspension polymerization method, a solution polymerization method, a dispersion polymerization method, an emulsion polymerization method, an emulsion polymerization aggregation method or the like is appropriately used. Although it can employ | adopt, it is preferable to manufacture by an emulsion polymerization method from a viewpoint of containing a crosslinking agent efficiently in the resin particle core, and controlling a particle size.

  When the resin particle core is produced by the emulsion polymerization method, the polymerization initiator, surfactant, and other optional additives (for example, chain transfer agent) are not particularly limited, and conventionally known ones may be used. it can.

  In the case of emulsion polymerization, the polymerization temperature is not particularly limited, but is preferably 50 to 120 ° C, more preferably 70 to 110 ° C, still more preferably 80 to 100 ° C, and particularly preferably 90 to 100. ° C. The polymerization time is not particularly limited, but preferably 2 to 12 hours.

≪Preparation of core-shell type resin particles≫
In the presence of the prepared resin particle core, a shell layer can be formed outside the resin particle core by polymerizing the monomer B and, if necessary, a monomer other than the monomer B.

  The method for producing the shell layer is not particularly limited, but the emulsion polymerization method is preferred for the same reason as described above. In the emulsion polymerization, the polymerization initiator, surfactant, and other optional additives (for example, chain transfer agent) are not particularly limited, and conventionally known ones can be used.

  In the case of emulsion polymerization, the polymerization temperature is not particularly limited, but is preferably 40 to 110 ° C, more preferably 50 to 100 ° C, still more preferably 60 to 90 ° C, and particularly preferably 70 to 80 ° C. ° C. The polymerization time is not particularly limited, but preferably 2 to 12 hours. When the reactivity of the monomer is different between the core manufacturing process and the shell manufacturing process, the polymerization temperature may be changed. For example, when the reactivity of the monomer is higher in the shell manufacturing process, a polymerization temperature lower than the polymerization temperature of the core manufacturing process may be set.

  Through the above steps, core-shell type resin particles in which a crosslinking agent is encapsulated in the core part can be obtained. In this method, resin particles having a desired crosslinking agent content can be obtained by changing the blending amount of the crosslinking agent when producing the resin particles.

≪Physical properties of resin particles≫
The volume average particle diameter of the resin particles is preferably 10 to 500 nm, preferably 50 to 300 nm, and preferably 100 to 200 nm. Within such a range, the resin particles are melted by heating to form a uniform resin coating layer. The volume average particle diameter of the resin particles is a value measured by the method described in the examples.

  The weight average molecular weight of the resin particles is preferably 50,000 to 1,000,000. Within such a range, the strength of the resin coating layer becomes appropriate, and the surface of the carrier particles is refreshed by abrasion.

  The weight average molecular weight of the resin particles is measured using GPC (gel permeation chromatography) under the following conditions. That is, the measurement sample is dissolved in tetrahydrofuran so that the concentration becomes 1 mg / mL. As dissolution conditions, it is carried out at room temperature for 5 minutes using an ultrasonic disperser. Next, after processing with a membrane filter having a pore size of 0.2 μm, a 10 μL sample solution is injected into the GPC. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve measured using monodisperse polystyrene standard particles. Ten polystyrenes are used for calibration curve measurement.

<GPC measurement conditions>
Apparatus: HLC-8220 (manufactured by Tosoh Corporation)
Column: TSKguardcolumn + TSKgelSuperHZM-M3 series (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Solvent: Tetrahydrofuran Flow rate: 0.2 mL / min
Detector: Refractive index detector (RI detector).

  When producing a resin coating layer having a two-layer structure, the amount of the crosslinking agent in the resin particles (lower layer resin particles) used for forming the lower layer is based on the total amount of the structural units derived from the monomers constituting the resin. 5 to 40% by mass, and more preferably 10 to 30% by mass. If it is such a range, since the lower layer excellent in abrasion resistance is formed, exposure of a core particle is suppressed. Therefore, chargeability can be maintained and carrier adhesion can be suppressed even after long-term use.

  When manufacturing a resin coating layer having a two-layer structure, the upper limit of the amount of the crosslinking agent compounded in the resin particles (upper layer resin particles) used for forming the upper layer is the total amount of structural units derived from the monomers constituting the resin. On the other hand, it is preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, and particularly preferably less than 12% by mass. If it is such a range, the film | membrane intensity | strength of an upper layer will become suitable, abrasion will advance moderately, and the carrier surface will be refreshed. As a result, contamination of the carrier surface with toner and external additives can be suppressed, and good chargeability can be maintained even after long-term use. On the other hand, the lower limit of the amount of the crosslinking agent in the upper layer resin particles is 0% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably more than 3% by mass. It is. In such a range, since it takes time until the upper layer is worn and the lower layer is exposed, the amount of toner spent on the surface of the lower layer is reduced, and the chargeability after long-time use is further improved. In other words, the resin coating layer of the carrier according to the present invention is preferably composed of a crosslinkable resin in both the lower layer and the upper layer.

  Under the present circumstances, it is preferable that the crosslinking agent compounding quantity of the resin particle for upper layers is 0 to 70% with respect to the crosslinking agent compounding quantity of the resin particle for lower layers, It is more preferable that it is 10 to 60%, and 20 to 20%. Particularly preferred is 50%. If it is such a range, the effect of this invention will become still more remarkable.

  In the resin particles, the structural unit derived from the monomer B and the crosslinking agent may be present in the same compartment. Under the present circumstances, if the crosslinking agent (block isocyanate etc.) with which the crosslinkable functional group was capped is selected, even if it exists in the same division, progress of the crosslinking reaction of both components can be suppressed.

  The obtained resin particles may be used for carrier preparation after drying by spray drying or the like, or may be used for carrier preparation in the state of a dispersion, and can be appropriately selected depending on the method for preparing the carrier.

(Adhesion of resin particles to core particles)
Examples of the method for coating the surface of the core particle with the resin particles include a wet coating method, a dry coating method, a coating method in which the wet coating method and the dry coating method are combined, and the dry coating method is preferable. In the case of the dry coating method, a large amount of resin is disposed in the concave portion of the core material particle, and a small amount of resin is disposed in the convex portion. Therefore, the volume resistivity of the carrier can be lowered appropriately, and the environmental difference in charge amount can be reduced. Moreover, in addition to the effect of the thickness distribution of the resin coating layer, the resin is filled in the recesses, so that the shape of the carrier particles becomes nearly spherical and the fluidity is improved.

The dry coating method is a method in which a coating layer resin is coated on the surface of the core particle by applying mechanical impact or heat, and a resin coating layer is formed on the surface of the core particle by the following steps:
1: The core material particles and the coating material in which the resin particles for the coating layer are mixed and dispersed are mechanically stirred to attach the coating material to the surface of the core material particles. 2: Then, the core is applied by applying mechanical impact or heat. The resin particles for the coating layer in the coating material adhering to the surface of the material particles are melted or softened and fixed to form a resin coating layer. 3: The coating layer having a desired thickness is repeated by repeating steps 1 and 2 as necessary. Form.

  Examples of the device for applying mechanical impact include a rotor and a liner such as a high-speed stirring mixer with a horizontal stirring blade or a turbo mill (manufactured by Freund Turbo Corporation), a pin mill, a kryptron (manufactured by Kawasaki Heavy Industries, Ltd.), and the like. A high-speed stirring mixer with horizontal stirring blades is preferably used.

  When performing under a heating, heating temperature becomes like this. Preferably it is 60-130 degreeC, More preferably, it is 80-120 degreeC, More preferably, it is 100-120 degreeC. The heating time is preferably 10 to 120 minutes, more preferably 20 to 90 minutes, still more preferably 30 to 60 minutes, and particularly preferably 40 to 50 minutes. Under such heating conditions, the crosslinking reaction in the resin particles can be advanced while melting the resin particles. Moreover, aggregation of the coated carrier particles can be suppressed. Furthermore, when a new resin coating layer (upper layer) is formed on a resin coating layer (lower layer) having a crosslinked structure, the lower layer and upper layer are maintained while maintaining the lower layer crosslinking structure by performing under such conditions. And fuse. As a result, peeling between the lower layer and the upper layer is less likely to occur, and changes in the carrier charging performance are suppressed. Therefore, good chargeability can be maintained even after long-term use.

  The amount of the resin particles used is preferably 0.5 to 20 parts by mass, more preferably 1 to 10 parts by mass, and 2 to 5 parts by mass with respect to 100 parts by mass of the core particles. Is even more preferred.

[Physical properties of the carrier]
(Thickness of resin coating layer)
The average film thickness of the resin coating layer of the carrier according to the present invention is preferably 0.05 to 4.0 μm, and preferably 0.2 to 3.0 μm from the viewpoint of improving durability and reducing volume resistance. It is more preferable. When the resin coating layer has a two-layer structure composed of a lower layer and an upper layer, the thickness of the lower layer is preferably 0.2 to 2.0 μm, more preferably 0.5 from the viewpoint of suppressing exposure of the core material particles. ˜1.0 μm. Further, the film thickness of the upper layer is preferably 0.5 to 2.8 μm, more preferably 0.7 to 1.0 μm, from the viewpoint of improving wearability and developability.

  The average film thickness of the resin coating layer is calculated by the following method. In the focused ion beam apparatus “SMI2050” (manufactured by Hitachi High-Tech Science Co., Ltd.), the carrier particles are cut along the plane passing through the center of the carrier particles to prepare a measurement sample. The cross section of the measurement sample is observed with a transmission electron microscope “JEM-2010F” (manufactured by JEOL Ltd.) with a field of view of 5000 times, and the value of the maximum film thickness and the minimum film thickness in the field of view The average value when the number of measurements is 50 is taken as the film thickness of the resin coating layer. It should be noted that the resin coating layer has good adhesion to the core particles and has wear resistance, even if the resin used for forming the resin coating layer is formed in a uniform layer state. There is no problem even if it is formed in a fixed form.

(Difference in crosslinking degree of resin coating layer)
The difference in the degree of crosslinking in the resin coating layer can be confirmed by, for example, identifying a functional group resulting from the crosslinked structure by a known analysis means such as FT-IR and comparing the peak intensity in the film thickness direction. For example, when the resin coating layer has a two-layer structure, after the FT-IR measurement of the resin-coated carrier, the upper layer is worn to expose the lower layer, and the FT-IR measurement is performed again. For each of the obtained FT-IR spectra, the area of the infrared absorption peak of the group generated by the crosslinking reaction is A, and the area B of the infrared absorption peak (internal standard peak) of the group not changed by the crosslinking reaction is the peak area. The ratio R = A / B is determined. When the peak area ratio of the lower layer is Ru and the peak area ratio of the upper layer is Rt, the ratio of the crosslinking degree of the upper layer to the lower layer can be expressed as Rt / Ru × 100. The ratio is preferably 0 to 70%. In addition, the confirmation method of a crosslinking degree difference is not restrict | limited to said thing.

(Volume resistivity)
The volume resistivity of the carrier according to the present invention is preferably 10 ⁷ to 10 ¹² Ω · cm, and more preferably 10 ⁸ to 10 ¹¹ Ω · cm. Such a range is also suitable for forming a high-density toner image. The volume resistivity is a resistance that is dynamically measured under developing conditions using a magnetic brush. Specifically, an aluminum electrode drum having the same dimensions as the photosensitive drum is replaced with a photosensitive drum, and carrier particles are supplied onto the developing sleeve to form a magnetic brush. The magnetic brush is rubbed against an aluminum electrode drum, a voltage (500 V) is applied between the developing sleeve and the drum, and the current flowing between the two is measured, whereby the volume resistivity of the carrier is expressed by the following equation (2). It can ask for.

In the above formula 2, the respective abbreviations are as follows:
DVR: Volume resistivity (Ω · cm)
V: Voltage (V) between the developing sleeve and the drum
I: Measurement current value (A)
N: Development nip width (cm)
L: Development sleeve length (cm)
Dsd: distance between the developing sleeve and the drum (cm)
In this specification, the measurement is performed at V = 500 V, N = 1 cm, L = 6 cm, and Dsd = 0.6 mm.

<Two-component developer>
The present invention also provides a two-component developer comprising the above-described electrostatic charge image developing carrier and an electrostatic charge image developing toner.

[Toner for electrostatic image development]
The electrostatic image developing toner (hereinafter also simply referred to as “toner”) contained in the two-component developer of the present invention contains toner particles obtained by attaching an external additive to toner base particles.

(Toner base particles)
The toner base particles according to the present invention preferably contain a binder resin. The toner base particles may contain additives such as a colorant, a release agent (wax), and a charge control agent as necessary.

<Constituent components of toner base particles>
[Binder resin]
The binder resin of the toner base particles preferably contains a crystalline resin, and more preferably contains an amorphous resin. Thereby, at the time of heat fixing, the crystalline resin and the amorphous resin are compatible with each other, and the low temperature fixing property of the toner is improved. That is, the toner contained in the secondary developer of the present invention contains a crystalline resin.

(Crystalline resin)
The crystalline resin refers to a resin having a clear endothermic peak instead of a stepwise endothermic change in differential scanning calorimetry (DSC). The clear endothermic peak specifically means a peak whose half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

  The crystalline resin is not particularly limited as long as it has the above characteristics, and a conventionally known crystalline resin in this technical field can be used. Specific examples thereof include a crystalline polyester resin, a crystalline polyurethane resin, a crystalline polyurea resin, a crystalline polyamide resin, and a crystalline polyether resin. Crystalline resins can be used singly or in combination of two or more.

  Among these, the crystalline resin is preferably a crystalline polyester resin. Here, the “crystalline polyester resin” is obtained by a polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a derivative thereof with a divalent or higher alcohol (polyhydric alcohol) and a derivative thereof. Among known polyester resins, the resin satisfies the endothermic characteristics.

  The melting point of the crystalline polyester resin is preferably 55 to 90 ° C, and more preferably 60 to 85 ° C. In such a range, sufficient low-temperature fixability can be obtained. The melting point of the crystalline polyester resin can be controlled by the resin composition. Moreover, the value measured by the method as described in an Example is employ | adopted for melting | fusing point of resin in this specification.

  As the valences of the polyvalent carboxylic acid and the polyhydric alcohol constituting the crystalline polyester resin, each is preferably 2 to 3, and particularly preferably 2 respectively. In the following, the valence is 2 respectively. (In other words, the dicarboxylic acid component and the diol component) will be described in detail.

  As the dicarboxylic acid component, an aliphatic dicarboxylic acid is preferably used, and an aromatic dicarboxylic acid may be used in combination as necessary. As the aliphatic dicarboxylic acid, it is preferable to use a linear one. By using a linear type, there is an advantage that crystallinity is improved. A dicarboxylic acid component may be used independently and may be used 2 or more types.

  Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Acid (dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (tetradecanedioic acid), 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecane Examples thereof include dicarboxylic acid and 1,18-octadecanedicarboxylic acid. Among these, aliphatic dicarboxylic acids having 6 to 14 carbon atoms excluding carboxyl carbon are preferable, aliphatic dicarboxylic acids having 8 to 12 are more preferable, and aliphatic dicarboxylic acids having 8 to 10 are even more preferable.

  Examples of the aromatic dicarboxylic acid that can be used together with the aliphatic dicarboxylic acid include phthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyl. And dicarboxylic acid. Among these, terephthalic acid, isophthalic acid, and t-butylisophthalic acid are preferably used from the viewpoints of availability and emulsification ease.

  In addition to the above dicarboxylic acids, trivalent or more such as trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc. Polycarboxylic acids, maleic acid, fumaric acid, 3-hexenedioic acid, dicarboxylic acids having a double bond such as 3-octenedioic acid, and anhydrides of the above carboxylic acid compounds, 3 alkyl esters or the like may be used.

  As the dicarboxylic acid component for forming the crystalline polyester resin, the aliphatic dicarboxylic acid content is preferably 50 constituent mol% or more, more preferably 70 constituent mol% or more, and still more preferably 80 It is at least 100% by mole, particularly preferably 100% by mole. When the content of the aliphatic dicarboxylic acid in the dicarboxylic acid component is 50 constituent mol% or more, the crystallinity of the crystalline polyester resin can be sufficiently ensured.

  Moreover, it is preferable to use aliphatic diol as a diol component, and you may use together diols other than aliphatic diol as needed. As the aliphatic diol, a linear diol is preferably used. By using a linear type, there is an advantage that crystallinity is improved. A diol component may be used individually by 1 type, and may be used 2 or more types.

  Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7- Heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14- Tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol, neopentyl glycol and the like can be mentioned. Among these, an aliphatic diol having 2 to 12 carbon atoms is preferable, an aliphatic diol having 5 to 10 carbon atoms is more preferable, and an aliphatic diol having 7 to 9 carbon atoms is still more preferable.

  Examples of the diol that can be used together with the aliphatic diol include a diol having a double bond, a diol having a sulfonic acid group, and the like. Specifically, examples of the diol having a double bond include 1,4- Examples include butenediol, 2-butene-1,4-diol, 3-butene-1,6-diol, and 4-butene-1,8-diol. Moreover, you may use trihydric or more polyhydric alcohols, such as glycerol, pentaerythritol, a trimethylol propane, and sorbitol.

  As the diol component for forming the crystalline polyester resin, the content of the aliphatic diol is preferably 50 component mol% or more, more preferably 70 component mol% or more, and still more preferably 80 component mol%. % Or more, and particularly preferably 100 constituent mol%. When the content of the aliphatic diol in the diol component is 50 constituent mol% or more, the crystallinity of the crystalline polyester resin can be secured, and a toner excellent in low-temperature fixability can be obtained.

  The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 3,000 to 100,000 from the viewpoint of ensuring both sufficient low-temperature fixability and excellent long-term heat-resistant storage stability. 5,000 to 50,000, more preferably 5,000 to 20,000. In addition, in this specification, the value calculated | required by the method as described in an Example is employ | adopted for a weight average molecular weight (Mw).

  The use ratio of the diol component to the dicarboxylic acid component is such that the molar ratio ([OH] / [COOH]) of the hydroxyl group of the diol component to the carboxyl group of the dicarboxylic acid component is 2.5 / 1 to 0.5 / 1 is preferable, and 2/1 to 1/1 is more preferable.

  A hybrid crystalline polyester resin having a crystalline polyester polymer segment and a polymer segment other than the crystalline polyester polymer segment can also be used as the crystalline resin according to the present invention.

  The method for producing the crystalline polyester resin is not particularly limited, and can be produced by polycondensation (esterification) of the dicarboxylic acid and dialcohol using a known esterification catalyst.

  Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium; compounds containing Group 2 elements such as magnesium and calcium; aluminum, zinc, manganese, antimony, titanium, tin, Metal compounds such as zirconium and germanium; phosphorous acid compounds; phosphoric acid compounds; and amine compounds. Specifically, examples of the tin compound include dibutyltin oxide, tin octylate, tin dioctylate, and salts thereof. Examples of titanium compounds include titanium alkoxides such as tetranormal butyl titanate, tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxy titanium stearate; titanium tetraacetylacetonate, titanium lactate, titanium triethanolamine. Examples include titanium chelates such as nates. Examples of germanium compounds include germanium dioxide. Furthermore, examples of the aluminum compound include oxides such as polyaluminum hydroxide and aluminum alkoxides such as tributylaluminate. You may use these individually by 1 type or in combination of 2 or more types.

  The polymerization temperature is not particularly limited, but is preferably 150 to 250 ° C. The polymerization time is not particularly limited, but is preferably 0.5 to 15 hours. During the polymerization, the pressure in the reaction system may be reduced as necessary.

  The content of the crystalline resin is preferably 0.5 to 20% by mass and more preferably 1 to 10% by mass in the toner base particles.

(Amorphous resin)
An amorphous resin is a resin that does not have a melting point and has a relatively high glass transition temperature (Tg) when differential scanning calorimetry (DSC) is performed on the resin. The glass transition temperature (Tg) of the amorphous resin is not particularly limited, but is from 25 to 60 ° C. from the viewpoint of reliably obtaining fixing properties such as low-temperature fixing properties and heat resistance such as heat storage stability and blocking resistance. It is preferable that In addition, in this specification, the value measured by the method as described in an Example is employ | adopted for the glass transition temperature (Tg) of resin.

  The amorphous resin is not particularly limited as long as it has the above characteristics, and conventionally known amorphous resins in this technical field can be used. Specific examples thereof include vinyl resin, urethane resin, urea resin and the like. Among these, vinyl resin is preferable because it is easy to control thermoplasticity.

  The vinyl resin is not particularly limited as long as a vinyl compound is polymerized, and examples thereof include (meth) acrylic acid ester resins, styrene- (meth) acrylic acid ester resins, and ethylene-vinyl acetate resins. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Among the above vinyl resins, a styrene- (meth) acrylic ester resin is preferable in consideration of plasticity at the time of heat fixing. Therefore, hereinafter, a styrene- (meth) acrylic ester resin (hereinafter also referred to as “styrene- (meth) acrylic resin”) as an amorphous resin will be described.

The styrene- (meth) acrylic resin is formed by addition polymerization of at least a styrene monomer and a (meth) acrylic acid ester monomer. Styrene monomer as referred to herein, in addition to styrene represented by the structural formula _{CH 2 = CH-C 6 H} 5, is intended to include a structure having a known side-chain or functional groups styrene structure. In addition, the (meth) acrylic acid ester monomer referred to here is an acrylic acid ester derivative or methacrylic acid in addition to the acrylic acid ester compound or methacrylic acid ester compound represented by CH ₂ = CHCOOR (R is an alkyl group). It includes an ester compound having a known side chain or functional group in the structure of an ester derivative or the like.

  An example of a styrene monomer and a (meth) acrylic acid ester monomer capable of forming a styrene- (meth) acrylic resin is shown below.

  Specific examples of the styrene monomer include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene. , P-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, and the like. These styrene monomers can be used alone or in combination of two or more.

  Specific examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, (meth) T-butyl acrylate, isobutyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylic acid Examples thereof include phenyl, diethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and the like. These (meth) acrylic acid ester monomers can be used alone or in combination of two or more.

  Furthermore, the styrene- (meth) acrylic resin may contain the following monomer compounds in addition to the styrene monomer and the (meth) acrylic acid ester monomer.

  Examples of such monomer compounds include compounds having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl ( Examples thereof include compounds having a hydroxyl group such as (meth) acrylate. These monomer compounds can be used alone or in combination of two or more.

  The method for producing the styrene- (meth) acrylic resin is not particularly limited, and an arbitrary polymerization initiator such as a peroxide, a persulfide, a persulfate, an azo compound or the like usually used for the polymerization of the above monomer is used. , Polymerization methods such as bulk polymerization, solution polymerization, emulsion polymerization method, miniemulsion method, and dispersion polymerization method. Moreover, the chain transfer agent generally used can be used in order to adjust molecular weight. The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans such as n-octyl mercaptan, mercapto fatty acid esters, and the like.

  The content of the amorphous resin is preferably 60 to 90% by mass and more preferably 65 to 85% by mass with respect to the toner.

[Colorant]
Examples of the colorant include known inorganic or organic colorants. Hereinafter, specific colorants are shown.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment Red 2, 3, 5, 6, 7, 15, 15, 48: 1, 53: 1, 57: 1, 60, 63, 64, 68, the same 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 139, 144, 149, 150, 163, 166, 170, 177, 178, 184, 202, 206, 207, 209, 222, 238, 269, and the like.

  Examples of the colorant for orange or yellow include C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 12, 14, 15, 17, 74, 83, 93, 94, 138, 155, 162, 180, 185, and the like.

  Examples of the colorant for green or cyan include C.I. I. Pigment Blue 2, 3, 15, 15, 15: 2, 15: 3, 15: 4, 16, 17, 17, 60, 62, 66, C.I. I. And CI Pigment Green 7.

  Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 2, 6, 14, 15, 16, 19, 21, 21, 33, 44, 56, 61, 77, 79, 80, 81, 82, the same 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 and the like.

  These colorants can be used alone or in combination of two or more.

  The content of the colorant is preferably 1 to 30% by mass, and more preferably 5 to 25% by mass in the toner base particles.

  As the colorant, a surface-modified one can also be used. As the surface modifier, conventionally known ones can be used, and specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, and the like can be preferably used.

〔Release agent〕
The release agent is not particularly limited. For example, hydrocarbon waxes such as polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, microcrystalline wax, carnauba wax, fatty acid ester wax, Known examples include sazol wax, rice wax, candelilla wax, jojoba oil wax, and beeswax wax.

  The content of the release agent is preferably 1 to 30 parts by mass and more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the binder resin.

[Charge control agent]
Examples of the charge control agent include metal complexes of salicylic acid derivatives such as zinc and aluminum (salicylic acid metal complexes), calixarene compounds, organic boron compounds, and fluorine-containing quaternary ammonium salt compounds.

  The content of the charge control agent is preferably 0 to 5 parts by mass with respect to 100 parts by mass of the binder resin.

<Physical properties of toner base particles>
[Average circularity]
From the viewpoint of improving charging environment stability and low-temperature fixability, the average circularity of the toner base particles is preferably 0.920 to 0.980, and more preferably 0.930 to 0.975. Here, as the average circularity, a value measured by the method described in the section “Physical properties of toner” described later is adopted.

〔Particle size〕
Regarding the particle size of the toner base particles, the volume average particle size is preferably 3 to 10 μm, and more preferably 4 to 7 μm. Within such a range, reproducibility of fine lines and high image quality of photographic images can be achieved, and toner consumption can be reduced as compared with the case of using a large particle size toner. Also, the fluidity of the toner can be secured. Here, as the volume average particle diameter of the toner base particles, a value measured by a method described in the section “Physical properties of toner” described later is adopted.

  The volume average particle size of the toner can be controlled by the concentration of the aggregating agent, the amount of the solvent added, the fusing time, the composition of the resin component, etc.

(External additive)
An external additive is attached to the surface of the toner base particles for the purpose of controlling fluidity and chargeability. As the external additive, conventionally known metal oxide particles can be used. For example, silica particles, titania particles, alumina particles, zirconia particles, zinc oxide particles, chromium oxide particles, cerium oxide particles, antimony oxide particles, Examples include tungsten oxide particles, tin oxide particles, tellurium oxide particles, manganese oxide particles, and boron oxide particles. These may be used alone or in combination of two or more.

  Particularly for silica particles, it is more preferable to use silica particles prepared by a sol-gel method. Silica particles produced by the sol-gel method have a feature that the particle size distribution is narrow, which is preferable in terms of suppressing variation in adhesion strength. The number average primary particle size of the silica particles formed by the sol-gel method is preferably 70 to 150 nm. Silica particles having a number average primary particle size in such a range have a larger particle size than other external additives, and thus have a role as spacers. By stirring and mixing therein, it has an effect of preventing embedding in the toner base particles, and also has an effect of preventing the toner base particles from fusing together.

  The number average primary particle size of the metal oxide particles other than the silica particles produced by the sol-gel method is preferably 10 to 70 nm, and more preferably 10 to 40 nm. The number average primary particle size of the metal oxide particles can be measured, for example, by a method obtained by image processing of an image taken with a transmission electron microscope.

  Moreover, you may use organic fine particles, such as homopolymers, such as styrene and methyl methacrylate, and these copolymers, as an external additive.

  The metal oxide particles used as the external additive according to the present invention preferably have a surface hydrophobized with a known surface treating agent such as a coupling agent. As the surface treatment agent, dimethyldimethoxysilane, hexamethyldisilazane (HMDS), methyltrimethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane and the like are preferable.

  Silicone oil can also be used as the surface treatment agent. Specific examples of silicone oils include, for example, cyclic compounds such as organosiloxane oligomers, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethylcyclotetrasiloxane, tetravinyltetramethylcyclotetrasiloxane, linear or Mention may be made of branched organosiloxanes. Alternatively, a highly reactive silicone oil in which a modifying group is introduced at the side chain, one end, both ends, the side chain one end, the side chain both ends, or the like may be used. Examples of the modifying group include an alkoxy group, a carboxyl group, a carbinol group, a higher fatty acid modification, a phenol group, an epoxy group, a methacryl group, and an amino group, but are not particularly limited. Further, for example, it may be a silicone oil having several modifying groups such as amino / alkoxy modification.

  Moreover, you may mix-process or use together, using dimethyl silicone oil, said modified | denatured silicone oil, and also another surface treating agent. Examples of the treating agent used in combination include silane coupling agents, titanate coupling agents, aluminate coupling agents, various silicone oils, fatty acids, fatty acid metal salts, esterified products thereof, rosin acid, and the like. .

  The degree of hydrophobicity of the metal oxide particles is preferably about 40 to 80%. In addition, the hydrophobization degree of metal oxide particles is indicated by a measure of wettability with respect to methanol, and is defined as the following formula 3.

  The method for measuring the degree of hydrophobicity is as follows. 0.2 g of particles to be measured are weighed and added to 50 ml of distilled water in a 200 ml beaker. Methanol is slowly added dropwise from a burette whose tip is immersed in the liquid until the entire particle is wet with slow stirring. When the amount of methanol necessary to completely wet the particles is a (ml), the degree of hydrophobicity is calculated by the above equation 3.

  In order to further improve the cleaning property and transfer property, it is possible to use a lubricant as an external additive. For example, the following salts of zinc stearate, aluminum, copper, magnesium, calcium, etc., zinc oleate, manganese, iron, copper, magnesium, etc., zinc palmitate, salts of copper, magnesium, calcium, etc., Examples thereof include metal salts of higher fatty acids such as zinc linoleic acid, salts such as calcium, and zinc ricinoleic acid, such as zinc and calcium.

  The amount of these external additives added is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the toner base particles.

  The toner according to the present invention preferably has a core-shell structure from the viewpoint of improving low-temperature fixability and heat-resistant storage stability. The core-shell structure is not limited to a structure in which the shell layer completely covers the core particles. For example, a structure in which the shell layer does not completely cover the core particles and the core particles are exposed in some places. It may be.

  The core-shell structure can be confirmed by observing the cross-sectional structure of the toner using a known means such as a transmission electron microscope (TEM) or a scanning probe microscope (SPM).

(Toner production method)
≪Method for producing toner base particles≫
The toner base particles according to the present invention can be produced, for example, by an emulsion aggregation method. The production method for producing the toner base particles according to the present invention by the emulsion aggregation method includes, for example, using a dispersion liquid (a) containing crystalline resin fine particles and a dispersion liquid (b) containing amorphous resin fine particles as an aqueous medium. And a step of preparing a mixed dispersion, and a step of heating the mixed dispersion to agglomerate the amorphous resin particles and the crystalline resin particles to form toner base particles. In the present specification, the “aqueous medium” refers to a medium containing at least 50% by mass of water, and examples of components other than water include organic solvents that dissolve in water. For example, methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, dimethylformamide, methyl cellosolve, tetrahydrofuran and the like can be mentioned. Among these, it is preferable to use an organic organic solvent such as methanol, ethanol, isopropanol, and butanol, which is an organic solvent that does not dissolve the resin. Preferably, only water is used as the aqueous medium.

  The said manufacturing method can be comprised as what includes each following process, for example. Here, the following examples describe the case where the crystalline resin fine particles are crystalline polyester resin fine particles, and the toner base particles contain a colorant, and the technical scope of the present invention is these. It is not necessarily limited to the form.

(1) a step of preparing a colorant particle dispersion in which colorant particles are dispersed;
(2) Dispersing the crystalline polyester resin in an organic solvent, emulsifying and dispersing it in an aqueous dispersion medium, and removing the organic solvent to prepare a dispersion containing crystalline polyester resin fine particles. Preparation of dispersion (a) Process,
(3) preparing a dispersion (b) containing amorphous resin fine particles, a step of preparing the dispersion (b),
(3) A step of preparing a mixed dispersion, wherein each dispersion prepared in (1) to (3) above is added to an aqueous medium to prepare a mixed dispersion,
(4) Aggregated particle formation step of forming toner base particles by aggregating the amorphous resin fine particles and the crystalline resin fine particles by heating the mixed dispersion prepared in (3) above,
(5) A maturing step of aging the aggregated particles formed in (4) above with heat energy to control the shape and obtaining toner base particles,
(6) a cooling step for cooling the dispersion of toner base particles;
(7) A filtration / washing step of filtering the toner base particles from the aqueous medium and removing the surfactant from the toner base particles.
(8) A drying step of drying the washed toner base particles.

  As described above, the toner base particles according to the present invention include those composed of the steps (5) to (8) that can be added to the essential steps (1) to (4) as necessary. it can.

  In carrying out the above-described steps, conventionally known knowledge can be referred to as appropriate. For example, the dispersion liquid (a) containing the crystalline resin fine particles and the dispersion liquid (b) containing the amorphous resin fine particles are prepared using various emulsification methods such as a method of emulsifying by mechanical shearing force. However, it is preferable to prepare using a method called a phase inversion emulsification method. In particular, when the dispersion (a) is prepared by a phase inversion emulsification method, oil droplets can be uniformly dispersed by changing the stability of the carboxyl group of the polyester. It is excellent in that it is not dispersed by shear force. In the “phase inversion emulsification method”, a resin is dissolved in an organic solvent to obtain a resin solution, a neutralization step in which a neutralizer is added to the resin solution, and the neutralized resin solution is dispersed in an aqueous system. By passing through an emulsification step of emulsifying and dispersing in a medium to obtain a resin emulsion, and a desolvation step of removing the organic solvent from the resin emulsion, a dispersion of resin fine particles is obtained. The particle size of the resin fine particles in the dispersion can be controlled by changing the amount of neutralizing agent added. The average particle diameter of the crystalline resin fine particles is preferably 100 to 300 nm as a volume-based median diameter. The measuring method of the average particle diameter is as described in the examples described later.

Further, the toner base particles having a core-shell structure can be obtained by using the toner base particles as a core and providing a shell layer on the surface thereof. By adopting a core-shell structure, heat-resistant storage properties and low-temperature fixability can be further improved. In order to produce toner base particles having a core-shell structure, for example, in the production method described above, after the aggregated particle forming step (4), the following steps are performed:
(4 ′) Using the toner base particles prepared in the above (4) as core particles, a shell dispersion (c) containing amorphous resin fine particles is added to the mixed dispersion, and a shell is formed on the surface of the core particles. The step of forming the step may be performed, and then the step (5) and subsequent steps may be performed.

<Method for producing toner particles>
This is a step of preparing toner particles by adding and mixing external additive particles to the dried toner base particles. Examples of the method for adding the external additive include a dry method in which the external additive is added in powder form to the dried toner base particles. Examples of the mixing device include mechanical mixing devices such as a Henschel mixer and a coffee mill. It is done.

(Physical properties of toner)
≪Average particle diameter≫
The average particle diameter of the toner (toner particles) according to the present invention is preferably 3 to 10 μm as a volume-based median diameter. If it is 3 μm or more, the chargeability of the carrier is hardly lowered by spent. When the thickness is 10 μm or less, toner scattering can be suppressed.

  The volume-based median diameter (D50) of toner (toner particles) can be measured and calculated using an apparatus in which a computer system for data processing is connected to “Multisizer 3 (manufactured by Beckman Coulter)”. . As a measuring procedure, 0.02 g of toner particles and 20 ml of a surfactant solution (for the purpose of dispersing toner particles, for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water). After being blended, ultrasonic dispersion is performed for 1 minute to prepare a toner particle dispersion. This toner particle dispersion is poured into a beaker containing ISOTON II (manufactured by Beckman Coulter) in a sample stand with a pipette until the measured concentration is 5 to 10%, and the measuring machine count is set to 25,000. To measure. The aperture size of the multisizer 3 is 100 μm. The frequency number obtained by dividing the measurement range of 1 to 30 μm into 256 parts is calculated, and the particle diameter of 50% from the larger volume integrated fraction is defined as the volume-based median diameter (D50).

  The volume average particle diameter of the toner (toner particles) can be controlled by controlling the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and the like in the above production method.

≪Average circularity≫
The average circularity of the toner (toner particles) according to the present invention is preferably 0.920 to 0.980, and more preferably 0.930 to 0.975. In such a range, the toner is more easily charged. The average circularity of the toner (toner particles) can be controlled by controlling the temperature, time, etc. during the aging process in the above-described production method.

  The average circularity can be measured using, for example, a flow particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation). Specifically, it can be measured by the following method. The toner particles are moistened in an aqueous surfactant solution and dispersed by ultrasonic dispersion for 1 minute. Thereafter, using “FPIA-3000”, measurement is performed at an appropriate density with an HPF detection number of 3000 to 10,000 in the measurement condition HPF (high magnification imaging) mode, and the circularity of each particle is calculated by the following formula 4. A value obtained by adding the calculated circularity of each particle and dividing by the total number of particles measured is the average circularity.

[Method for producing two-component developer]
The two-component developer according to the present invention can be produced by mixing the carrier and the toner using a mixing device.

  Examples of the mixing device include a Henschel mixer, a Nauter mixer, and a V-type mixer.

  When producing the two-component developer according to the present invention, the amount of toner is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the carrier.

<Image forming method>
The two-component developer of the present invention can be used in various known electrophotographic image forming methods, for example, a monochrome image forming method or a full color image forming method. In the full-color image forming method, four types of color developing devices for yellow, magenta, cyan, and black, and one electrostatic charge image carrier (also referred to as “electrophotographic photosensitive member” or simply “photosensitive member”) Any of the image forming methods such as a four-cycle image forming method constituted by a color developing device and an image forming unit having an electrostatic charge image carrier for each color, respectively. Methods can also be used.

  Specifically, as the image forming method, the two-component developer of the present invention is used, for example, electrostatic charging is performed by charging (charging process) on an electrostatic charge image carrier with a charging device and exposing the image. The electrostatic charge image (exposure process) formed on the toner is developed by charging the toner with a carrier in the two-component developer of the present invention and developing it in a developing device to obtain a toner image (development process). Then, the toner image is transferred to a sheet (transfer process), and then the toner image transferred onto the sheet is fixed on the sheet (fixing process) by a fixing process such as a contact heating method to obtain a visible image. .

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. In the following examples, the operation was performed at room temperature (20 to 25 ° C.) unless otherwise specified. Unless otherwise specified, “%” and “part” mean “% by mass” and “part by mass”, respectively.

<Creation of carrier>
[Production of resin particles]
(Preparation of resin particle 1AM)
(1) Production of resin particle 1A In a flask equipped with a stirrer,
175 parts by mass of cyclohexyl methacrylate 101 parts by mass of bisphenol A diglycidyl ether was added and heated to 90 ° C. to prepare a mixed solution [a1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [a1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [1A] in which resin particles 1A containing a crosslinking agent are dispersed.

(2) Production of Resin Particle 1AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [1A], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 155 parts by weight Methyl methacrylate 20 parts by weight Methacrylic acid 51 parts by weight n-Octyl-3-mercaptopropionate 4 parts by weight of a mixed solution [a2] is added dropwise over 1 hour. After completion of dropping, polymerization is carried out by heating and stirring for 2 hours while maintaining at 80 ° C., and then the reaction system is cooled to 28 ° C. to have a composite structure in which the surface of the resin particles 1A is coated with resin. A resin particle dispersion [1AM] in which resin particles 1AM are dispersed was prepared. The volume average particle diameter of the particles constituting [1AM] was 200 nm. The volume average particle diameter of the resin particles was measured by the following method.

[Method for measuring volume average particle diameter of resin particles]
The volume-based median diameter (D50) of the resin fine particles is a value obtained by measurement by a dynamic light scattering method using a known “Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.)”.

  Specifically, the following procedure is performed. First, a few drops of measurement resin fine particles are dropped into a 50 ml measuring cylinder, 25 ml of pure water is added, and dispersed for 3 minutes using an ultrasonic cleaner “US-1 (manufactured by ASONE Co., Ltd.)” to prepare a measurement sample. To do. Next, 3 ml of the measurement sample is put into the cell of “Microtrack UPA-150”, and it is confirmed that the value of Sample Loading is in the range of 0.1-100. And it measures on the following conditions.

≪Measurement conditions≫
Transparency (transparency): Yes
Refractive Index (refractive index): 1.59
Particle Density (particle specific gravity): 1.05 g / cm ³
Spherical Particles (Spherical Particles): Yes
≪Solvent condition≫
Refractive Index (refractive index): 1.33
Viscosity:
High (temp) 0.797x10 ^-3 Pa · S
Low (temp) 1.002 × 10 ⁻³ Pa · S.

(Preparation of resin particle 1BM)
(1) Production of resin particles 1B In a flask equipped with a stirrer,
235 parts by mass of cyclohexyl methacrylate 30 parts by mass of bisphenol A diglycidyl ether was added and heated to 90 ° C. to prepare a mixed solution [b1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [b1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was carried out by stirring for 2 hours to prepare a resin particle dispersion [1B] in which resin particles 1B containing a crosslinking agent are dispersed.

(2) Production of Resin Particle 1BM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [1B], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 200 parts by weight Methyl methacrylate 20 parts by weight Methacrylic acid 15 parts by weight n-Octyl-3-mercaptopropionate 4 parts by weight of a mixed solution [b2] is added dropwise over 1 hour. After completion of the dropping, polymerization is carried out by heating and stirring for 2 hours while maintaining at 80 ° C., and then the reaction system is cooled to 28 ° C. to have a composite structure in which the resin particles 1B are coated with resin. A resin particle dispersion [1BM] in which resin particles 1BM are dispersed was prepared. The volume average particle diameter of the particles constituting [1BM] was 200 nm.

(Preparation of resin particle 2AM)
(1) Production of resin particle 2A In a flask equipped with a stirrer,
Cyclohexyl methacrylate 90 parts by mass Isophthalic acid 55 parts by mass was added and heated to 90 ° C. to prepare a mixed solution [c1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [c1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [2A] in which resin particles 2A containing a crosslinking agent are dispersed.

(2) Production of Resin Particle 2AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [2A], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 260 parts by mass Glycidyl methacrylate 95 parts by mass n-octyl-3-mercaptopropionic acid ester mixed solution [c2] mixed with 4 parts by mass is added dropwise over 1 hour. The polymerization is carried out by heating and stirring for 2 hours while maintaining the temperature, and then the reaction system is cooled to 28 ° C. to disperse the resin particles 2AM having a composite structure in which the surface of the resin particles 2A is coated with a resin. A resin particle dispersion [2AM] was prepared. The volume average particle diameter of the particles constituting [2AM] was 200 nm.

(Preparation of resin particle 2BM)
(1) Production of resin particles 2B In a flask equipped with a stirrer,
130 parts by mass of cyclohexyl methacrylate 16.6 parts by mass of isophthalic acid were added and heated to 90 ° C. to prepare a mixed solution [d1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [d1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [2B] in which resin particles 2B containing a crosslinking agent are dispersed.

(2) Production of Resin Particle 2BM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [2B], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 325 parts by weight Glycidyl methacrylate 28.4 parts by weight n-octyl-3-mercaptopropionate 4 parts by weight of a mixed solution [d2] was added dropwise over 1 hour, and after completion of the dropping, Polymerization is performed by heating and stirring for 2 hours while maintaining the temperature at 80 ° C., and then the reaction system is cooled to 28 ° C. to obtain resin particles 2BM having a composite structure in which the surface of the resin particles 2B is coated with a resin. A dispersed resin particle dispersion [2BM] was prepared. The volume average particle diameter of the particles constituting [2BM] was 200 nm.

(Preparation of resin particle 3AM)
(1) Production of resin particle 3A In a flask equipped with a stirrer,
90 mass parts of cyclohexyl methacrylate Hexamethylene diisocyanate 59.5 mass parts was added, and it heated at 90 degreeC, and prepared liquid mixture [e1] by which said compound was mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [e1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [3A] in which resin particles 3A containing a crosslinking agent are dispersed.

(2) Preparation of resin particle 3AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) was dissolved in 200 parts by mass of ion-exchanged water was added to the resin particle dispersion [3A], and the temperature was increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 262 parts by mass 2-hydroxyethyl methacrylate 92 parts by mass n-octyl-3-mercaptopropionic acid ester mixed solution [e2] mixed with 4 parts by mass over 1 hour, after completion of this addition The resin particles 3AM having a composite structure in which the polymerization is performed by heating and stirring for 2 hours while maintaining the temperature at 80 ° C., and then the reaction system is cooled to 28 ° C., and the surface of the resin particles 3A is coated with the resin. A resin particle dispersion [3AM] in which is dispersed is prepared. The volume average particle diameter of the particles constituting [3AM] was 200 nm.

(Preparation of resin particle 3BM)
(1) Production of resin particles 3B In a flask equipped with a stirrer,
30 parts by mass of cyclohexyl methacrylate 17.5 parts by mass of hexamethylene diisocyanate was added and heated to 90 ° C. to prepare a mixed solution [f1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [f1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was carried out by stirring for 2 hours to prepare a resin particle dispersion [3B] in which resin particles 3B containing a crosslinking agent are dispersed.

(2) Production of Resin Particle 3BM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [3B], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 425 parts by mass 2-hydroxyethyl methacrylate 27 parts by mass n-octyl-3-mercaptopropionic acid ester [f2] mixed with 4 parts by mass is added dropwise over 1 hour, and after completion of the addition The resin particles 3BM having a composite structure in which the polymerization is performed by heating and stirring for 2 hours while maintaining the temperature at 80 ° C., and then the reaction system is cooled to 28 ° C., and the surface of the resin particles 3B is coated with the resin. A resin particle dispersion [3BM] in which is dispersed is prepared. The volume average particle diameter of the particles constituting [3BM] was 200 nm.

(Preparation of resin particle 4AM)
(1) Production of resin particles 4A In a flask equipped with a stirrer,
175 parts by mass of cyclohexyl methacrylate 101 parts by mass of bisphenol A diglycidyl ether was added and heated to 90 ° C. to prepare a mixed solution [g1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [g1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [4A] in which resin particles 4A containing a crosslinking agent were dispersed.

(2) Production of Resin Particle 4AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [4A], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 155 parts by weight methyl methacrylate 20 parts by weight methacrylic acid 51 parts by weight n-octyl-3-mercaptopropionic acid ester 4 g of a mixed solution [g2] is added dropwise over 1 hour. After completion of the dropping, polymerization is carried out by heating and stirring for 2 hours while maintaining the temperature at 80 ° C., and then the reaction system is cooled to 28 ° C. to have a composite structure in which the resin particles 4A are coated with the resin. A resin particle dispersion [4AM] in which resin particles 4AM are dispersed was prepared. The volume average particle diameter of the particles constituting [4AM] was 200 nm.

(Preparation of resin particle 4BM)
(1) Production of resin particles 4B In a flask equipped with a stirrer,
Cyclohexyl methacrylate 212 parts by mass Bisphenol A diglycidyl ether 50 parts by mass was added and heated to 90 ° C. to prepare a mixed solution [h1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [h1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [4B] in which resin particles 4B containing a crosslinking agent were dispersed.

(2) Preparation of Resin Particle 4BM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [4B], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 192.5 parts by weight Methyl methacrylate 20 parts by weight Methacrylic acid 25 parts by weight n-Octyl-3-mercaptopropionic acid ester 4 ml of a mixed solution [h2] is added dropwise over 1 hour. After completion of this dropping, polymerization is carried out by heating and stirring for 2 hours while maintaining at 80 ° C., and then the reaction system is cooled to 28 ° C., and the resin particles 4B are coated with a resin. A resin particle dispersion liquid [4BM] in which resin particles 4BM having s are dispersed was prepared. The volume average particle diameter of the particles constituting [4BM] was 200 nm.

(Preparation of resin particle 5AM)
(1) Production of resin particle 5A In a flask equipped with a stirrer,
175 parts by mass of cyclohexyl methacrylate 101 parts by mass of bisphenol A diglycidyl ether was added and heated to 90 ° C. to prepare a mixed solution [i1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [i1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was carried out by stirring for 2 hours to prepare a resin particle dispersion [5A] in which resin particles 5A containing a crosslinking agent are dispersed.

(2) Preparation of resin particle 5AM To the resin particle dispersion [5A], an initiator solution prepared by dissolving 7.4 parts by mass of potassium persulfate (KPS) in 200 parts by mass of ion-exchanged water was added, and the temperature was increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 155 parts by weight Methyl methacrylate 20 parts by weight Methacrylic acid 51 parts by weight n-Octyl-3-mercaptopropionic acid ester 4 ml of a mixed solution [i2] is added dropwise over 1 hour. After completion of dropping, polymerization is carried out by heating and stirring for 2 hours while maintaining at 80 ° C., and then the reaction system is cooled to 28 ° C. to have a composite structure in which the surface of the resin particles 5A is coated with resin. A resin particle dispersion [5AM] in which resin particles 5AM are dispersed was prepared. The volume average particle diameter of the particles constituting [5AM] was 200 nm.

(Preparation of resin particle 5BM)
(1) Production of resin particles 5B In a flask equipped with a stirrer,
200 parts by mass of cyclohexyl methacrylate was added and heated to 90 ° C. to prepare a mixed solution [j1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [j1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [5B] in which the resin particles 5B are dispersed.

(2) Production of Resin Particles 5BM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [5B], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 185 parts by weight Methyl methacrylate 20 parts by weight Methacrylic acid 95 parts by weight n-Octyl-3-mercaptopropionate 4 parts by weight of mixed solution [j2] is added dropwise over 1 hour. After completion of the dropping, polymerization is carried out by heating and stirring for 2 hours while maintaining at 80 ° C., and then the reaction system is cooled to 28 ° C. to have a composite structure in which the resin particles 5B are coated with a resin. A resin particle dispersion [5BM] in which resin particles 5BM are dispersed was prepared. The volume average particle diameter of the particles constituting [5BM] was 200 nm.

(Preparation of resin particle 6AM)
(1) Production of resin particle 6A In a flask equipped with a stirrer,
100 parts by mass of cyclohexyl methacrylate 100 parts by mass of methacrylic acid was added and heated to 90 ° C. to prepare a mixed solution [k1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [k1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [6A] in which the resin particles 6A are dispersed.

(2) Preparation of Resin Particle 6AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) was dissolved in 200 parts by mass of ion-exchanged water was added to the resin particle dispersion [6A], and the temperature was increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 100 parts by weight Methacrylic acid 100 parts by weight n-octyl-3-mercaptopropionate 4 parts by weight of mixed solution [k2] was added dropwise over 1 hour, and after completion of the addition, 80 ° C. The polymerization is performed by heating and stirring for 2 hours while maintaining the temperature, and then the reaction system is cooled to 28 ° C., and the resin particles 6AM having a composite structure in which the resin is coated on the surface of the resin particles 6A are dispersed. A resin particle dispersion [6AM] was prepared. The volume average particle diameter of the particles constituting [6AM] was 200 nm.

(Preparation of resin particle 7AM)
(1) Preparation of resin particle 7A In a flask equipped with a stirrer,
180 parts by mass of styrene 101 parts by mass of bisphenol A diglycidyl ether was added and heated to 90 ° C. to prepare a mixed solution [l1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [l1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [7A] in which resin particles 7A containing a crosslinking agent are dispersed.

(2) Production of Resin Particle 7AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [7A], and the temperature is increased. After adjusting to 80 ° C,
170 parts by mass of styrene 51 parts by mass of methacrylic acid 51 parts by mass n-octyl-3-mercaptopropionic acid ester [12] mixed with 4 parts by mass was added dropwise over 1 hour, and maintained at 80 ° C. after the completion of the addition. Resin in which resin particles 7AM having a composite structure in which the surface of the resin particles 7A is coated with a resin are dispersed by heating and stirring for 2 hours to conduct polymerization, and then cooling the reaction system to 28 ° C. A particle dispersion [7AM] was prepared. The volume average particle diameter of the particles constituting [7AM] was 200 nm.

(Preparation of resin particle 7BM)
(1) Production of resin particles 7B In a flask equipped with a stirrer,
220 parts by mass of styrene 29.7 parts by mass of bisphenol A diglycidyl ether were added and heated to 90 ° C. to prepare a mixed solution [m1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [m1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [7B] in which resin particles 7B containing a crosslinking agent were dispersed.

(2) Preparation of Resin Particle 7BM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [7B], and the temperature is increased. After adjusting to 80 ° C,
Styrene 235 parts by mass Methacrylic acid 15 parts by mass n-Octyl-3-mercaptopropionic acid ester [m2] mixed with 4 parts by mass was added dropwise over 1 hour, and maintained at 80 ° C. after completion of the addition. Resin in which resin particles 7BM having a composite structure in which the surface of the resin particles 7B is coated with the resin are dispersed by heating and stirring for 2 hours to perform polymerization, and then cooling the reaction system to 28 ° C. A particle dispersion [7BM] was prepared. The volume average particle diameter of the particles constituting [7BM] was 200 nm.

(Preparation of resin particle 8AM)
(1) Production of resin particles 8A In a flask equipped with a stirrer,
175 parts by mass of cyclohexyl methacrylate 101 parts by mass of bisphenol A diglycidyl ether was added and heated to 90 ° C. to prepare a mixed solution [n1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [n1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [8A] in which resin particles 8A containing a crosslinking agent are dispersed.

(2) Production of Resin Particle 8AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [8A], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 175 parts by weight Methacrylic acid 51 parts by weight n-octyl-3-mercaptopropionate 4 parts by weight of a mixed solution [n2] was added dropwise over 1 hour. The polymerization is carried out by heating and stirring for 2 hours while maintaining the temperature, and then the reaction system is cooled to 28 ° C. to disperse the resin particles 8AM having a composite structure in which the resin is coated on the surface of the resin particles 8A. A resin particle dispersion [8AM] was prepared. The volume average particle diameter of the particles constituting [8AM] was 200 nm.

(Preparation of resin particle 9AM)
(1) Production of resin particles 9A In a flask equipped with a stirrer,
175 parts by mass of cyclohexyl methacrylate 101 parts by mass of bisphenol A diglycidyl ether was added and heated to 90 ° C. to prepare a mixed solution [o1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [o1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin particle dispersion [9A] in which resin particles 9A containing a crosslinking agent were dispersed.

(2) Production of Resin Particle 9AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [9A], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 175 parts by weight Methacrylic acid 51 parts by weight n-octyl-3-mercaptopropionate 4 parts by weight of mixed solution [o2] was added dropwise over 1 hour, and after completion of the addition, 80 ° C The polymerization is performed by heating and stirring for 2 hours while maintaining the temperature, and then the reaction system is cooled to 28 ° C. to disperse the resin particles 9AM having a composite structure in which the surface of the resin particles 9A is coated with a resin. A resin particle dispersion [9AM] was prepared. The volume average particle diameter of the particles constituting [9AM] was 200 nm.

(Preparation of resin particle 10AM)
(1) Preparation of resin particle 10A In a flask equipped with a stirrer,
235 parts by mass of cyclohexyl methacrylate 30 parts by mass of bisphenol A diglycidyl ether was added and heated to 90 ° C. to prepare a mixed solution [p1] in which the above compounds were mixed. Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., and the mixed solution [p1] was added to the surfactant solution. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours with a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was carried out by stirring for 2 hours to prepare a resin particle dispersion [10A] in which resin particles 10A containing a crosslinking agent were dispersed.

(2) Preparation of Resin Particle 10AM An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) is dissolved in 200 parts by mass of ion-exchanged water is added to the resin particle dispersion [10A], and the temperature is increased. After adjusting to 80 ° C,
Cyclohexyl methacrylate 220 parts by weight Methacrylic acid 15 parts by weight n-Octyl-3-mercaptopropionic acid ester [p2] mixed with 4 parts by weight was added dropwise over 1 hour, and after completion of the dropping, 80 ° C. The polymerization is carried out by heating and stirring for 2 hours while maintaining the temperature, and then the reaction system is cooled to 28 ° C. to disperse the resin particles 10AM having a composite structure in which the resin is coated on the surface of the resin particles 10A. A resin particle dispersion [10AM] was prepared. The volume average particle diameter of the particles constituting [10AM] was 200 nm.

[Production of carrier]
<Production Example 1: Production of Carrier 1>
As the core particles, Mn—Mg ferrite particles having an average particle diameter (volume-based median diameter) of 60 μm, a shape factor (SF-1) of 130, and a saturation magnetization of 8.2 × 10 ⁻⁵ Wb · m / kg are used. Got ready. 100 parts by mass of the “core particles” prepared above and 2 parts by mass of “resin particles 1AM” were put into a high-speed agitator with agitator blades, and the peripheral speed of the horizontal rotary blade was 8 m / sec. After mixing and stirring at 15 ° C. for 15 minutes, mixing at 120 ° C. for 50 minutes and applying the mechanical impact force to the surface of the core material particles, the first layer from the core material particle side (film thickness 1.0 μm) Formed.

  Next, 2 parts by weight of “resin particle 1BM” was added to the high-speed stirring mixer with stirring blades, mixed and stirred at 22 ° C. for 15 minutes under the condition that the peripheral speed of the horizontal rotary blade was 8 m / sec, and then 120 ° C. Was mixed for 50 minutes to form a “second layer from the core particle side” to prepare “Carrier 1”. The thickness of the resin coating layer was 1.95 μm (that is, the thickness of the second layer was 0.95 μm).

<Production Example 2: Production of Carrier 2>
“Carrier 2” was produced in the same manner as in Production Example 1 except that “resin particle 1AM” was changed to “resin particle 2AM” and “resin particle 1BM” was changed to “resin particle 2BM”. The film thickness of the resin coating layer was 1.0 μm for the first layer and 1.0 μm for the second layer.

<Production Example 3: Production of Carrier 3>
“Carrier 3” was produced in the same manner as in Production Example 1, except that “resin particle 1AM” was changed to “resin particle 3AM” and “resin particle 1BM” was changed to “resin particle 3BM”. The film thickness of the resin coating layer was 1.0 μm for the first layer and 1.0 μm for the second layer.

<Production Example 4: Production of Carrier 4>
“Carrier 4” was produced in the same manner as in Production Example 1 except that “resin particle 1AM” was changed to “resin particle 4AM” and “resin particle 1BM” was changed to “resin particle 4BM”. The film thickness of the resin coating layer was 1.0 μm for the first layer and 0.95 μm for the second layer.

<Production Example 5: Production of carrier 5>
“Carrier 5” was produced in the same manner as in Production Example 1, except that “resin particle 1AM” was changed to “resin particle 5AM” and “resin particle 1BM” was changed to “resin particle 5BM”. The film thickness of the resin coating layer was 1.0 μm for the first layer and 0.95 μm for the second layer.

<Production Example 6: Production of carrier 6>
“Carrier 6” was produced in the same manner as in Production Example 1 except that “resin particle 1AM” was changed to “resin particle 6AM” and “resin particle 1BM” was changed to “resin particle 6AM”. The film thickness of the resin coating layer was 1.0 μm for the first layer and 1.0 μm for the second layer.

<Production Example 7: Production of carrier 7>
“Carrier 7” was produced in the same manner as in Production Example 1, except that “resin particle 1AM” was changed to “resin particle 7AM” and “resin particle 1BM” was changed to “resin particle 7BM”. The film thickness of the resin coating layer was 1.0 μm for the first layer and 0.95 μm for the second layer.

<Production Example 8: Production of carrier 8>
“Carrier 8” was produced in the same manner as in Production Example 1, except that “resin particle 1AM” was changed to “resin particle 8AM” and “resin particle 1BM” was changed to “resin particle 8AM”. The film thickness of the resin coating layer was 1.0 μm for the first layer and 1.0 μm for the second layer.

<Production Example 9: Production of carrier 9>
A coating resin solution [9B] in which 20 parts by mass of methyltrimethoxysilane was dissolved and dispersed in 300 parts by mass of toluene was prepared.

  The coating resin solution [9B] was sprayed under heating at 70 ° C. while 100 parts by mass of “core material particles” were flowed into a rotating cylindrical flow device to coat the surface of the core material particles. Thereafter, a baking treatment was performed at 150 ° C. for 1 hour, and pulverization and classification were performed to form a “first layer from the core material particle side” (film thickness: 0.3 μm) on the surface of the core material particles.

  Next, 2 parts by weight of “resin particle 9AM” is put into a high-speed stirring mixer with stirring blades, and mixed and stirred at 22 ° C. for 15 minutes under the condition that the peripheral speed of the horizontal rotary blade is 8 m / sec. By mixing for 50 minutes, a “second layer from the core particle side” was formed, and “Carrier 9” was produced. The film thickness of the resin coating layer was 1.3 μm (that is, the film thickness of the second layer was 1.0 μm).

<Production Example 10: Production of Carrier 10>
“Carrier 10” was produced in the same manner as in Production Example 1 except that “resin particle 1AM” was changed to “resin particle 10AM” and “resin particle 1BM” was changed to “resin particle 9AM”. The film thickness of the resin coating layer was 1.0 μm for the first layer and 0.95 μm for the second layer.

  It shows in Table 1 about the component which comprises the resin particle used for each carrier. In Table 1, n1 and n2 represent the ratio (mass%) of the amount of the crosslinking agent to the total amount of the structural units derived from the respective monomers (monomer A, monomer B and other monomers). . In addition, the total amount of the structural unit derived from each monomer is substantially the same as the total amount of each monomer used as a raw material.

<Production of toner>
(1) Preparation of carbon black dispersion A solution prepared by stirring and dissolving 90 parts by mass of sodium dodecyl sulfate in 1600 parts by mass of ion-exchanged water is stirred, and 420 parts by mass of carbon black “Mogal L” is added to the solution. Partly added. Subsequently, a dispersion process was performed using a stirrer “CLEARMIX (M Technique Co., Ltd.)” to produce a “carbon black dispersion”. When the particle size of carbon black in the “carbon black dispersion” was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the mass average particle size was 110 nm.

(2) Preparation of crystalline polyester resin fine particle dispersion (a) Synthesis of crystalline polyester resin Dodecanedioic acid as a polyvalent carboxylic acid component in a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a temperature sensor, and a rectifying tower 189 parts by mass, 97 parts by mass of 1,6-hexanediol as a polyhydric alcohol component were added, the temperature of the reaction system was raised to 190 ° C. over 1 hour, and it was confirmed that the reaction system was uniformly stirred. Thereafter, Ti (OBu) ₄ as a catalyst was added in an amount of 0.006% by mass based on the total amount of the polyvalent carboxylic acid component, and the temperature of the reaction system was maintained at the same temperature while distilling off the produced water. The crystalline polyester resin [a] was obtained by increasing the temperature to 240 ° C. over 6 hours and then continuing the dehydration condensation reaction over 6 hours while maintaining the temperature at 240 ° C. .

(B) Production of crystalline polyester resin fine particles After adding methyl ethyl ketone and isopropyl alcohol to a reaction vessel equipped with an anchor blade for stirring power, the crystalline polyester resin [a] is coarsely pulverized with a hammer mill. Were gradually added and stirred to obtain a polyfunctional acrylate-modified polyester resin solution that was completely dissolved to form an oil phase. Next, a quantity of dilute aqueous ammonia solution was dropped into this oil phase while stirring, and ion-exchanged water was dropped into this oil phase to phase-invert and emulsify, and then the solvent was removed while reducing pressure with an evaporator to remove polyfunctional acrylate Modified polyester resin fine particles were generated, and further ion-exchanged water was added to adjust the solid content to 20% by mass, thereby obtaining a crystalline polyester resin fine particle dispersion [A].

  The volume-based median diameter of the resin fine particles in the obtained polyfunctional acrylate-modified polyester resin fine particle dispersion [A] was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). 185 nm.

(3) Preparation of styrene-acrylic copolymer resin fine particle dispersion (a) Production of resin fine particles 1H An anionic surfactant: dodecyl sulfate in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device. 7.08 parts by mass of sodium was dissolved in 3,010 parts by mass of ion-exchanged water to prepare a surfactant solution. While this surfactant solution was stirred at a stirring speed of 230 rpm under a nitrogen stream, the temperature in the reaction vessel was raised to 80 ° C.

Next, a polymerization initiator solution prepared by dissolving 9.2 parts by mass of a polymerization initiator: potassium persulfate (KPS) in 200 parts by mass of ion-exchanged water is added to the surfactant solution, and the temperature in the reaction vessel is set to 75 ° C. After
-69.4 parts by mass of styrene-28.3 parts by mass of n-butyl acrylate-A mixed solution [1] obtained by mixing 2.3 parts by mass of methacrylic acid is added dropwise over 1 hour, and further 2 at 75 ° C. By stirring and polymerizing for a time, a resin fine particle dispersion [1H] in which the resin fine particles [1H] are dispersed was prepared.
(B) Production of resin fine particles 1HM In a flask equipped with a stirrer,
-97.1 parts by mass of styrene-39.7 parts by mass of n-butyl acrylate-3.22 parts by mass of methacrylic acid-5.6 parts by mass of n-octyl-3-mercaptopropionic acid ester,
-98.0 mass parts of pentaerythritol tetrabehenate was added, and it heated at 90 degreeC, and prepared liquid mixture [2] by which said compound was mixed.

  Meanwhile, a surfactant solution in which 1.6 parts by mass of sodium dodecyl sulfate was dissolved in 2,700 parts by mass of ion-exchanged water was prepared in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. This was heated to 98 ° C., 28 parts by mass of the resin fine particle dispersion [1H] was added to the surfactant solution in terms of solid content, and then the mixed solution [2] was added. Further, a dispersion (emulsion) was prepared by mixing and dispersing for 2 hours using a mechanical dispersion device “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.

Next, an initiator solution prepared by dissolving 5.1 parts by mass of potassium persulfate (KPS) in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to the emulsion, and the reaction system was heated at 98 ° C. Polymerization was performed by stirring for 2 hours to prepare a resin fine particle dispersion [1HM] in which resin fine particles [1HM] having a composite structure in which the resin layer is coated on the surface of the resin fine particles [1H] are dispersed.
(C) Preparation of resin fine particle 1HML An initiator solution in which 7.4 parts by mass of potassium persulfate (KPS) was dissolved in 200 parts by mass of ion-exchanged water was added to the above resin fine particle dispersion [1HM], and the temperature was increased. After adjusting to 80 ° C,
-Styrene 277 parts by mass-N-butyl acrylate 113 parts by mass-Methacrylic acid 9.21 parts by mass-n-octyl-3-mercaptopropionic acid ester 10.4 parts by mass mixed liquid [3] After dropwise addition over time, polymerization is carried out by heating and stirring for 2 hours while maintaining at 80 ° C., and then the reaction system is cooled to 28 ° C., and the resin layer is coated on the surface of the resin fine particles [1HM]. A styrene-acrylic copolymer resin fine particle dispersion [B] in which resin fine particles [1HML] having a composite structure are dispersed was prepared.

(4) Formation of toner base particles (a) Formation of core particles In a reaction vessel equipped with a stirring device, a temperature sensor, a cooling pipe, and a nitrogen introducing device,
-Crystalline polyester resin fine particle dispersion [A] 50 parts by mass (solid content conversion)
-Styrene-acrylic copolymer resin fine particle dispersion [B] 400 parts by mass (solid content conversion)
・ Ion-exchanged water 1100 parts by mass ・ Carbon black dispersion 100 parts by mass (solid content conversion)
After adjusting the liquid temperature to 30 ° C., 5 mol / liter sodium hydroxide aqueous solution was added to adjust the pH to 10.0.

  While stirring this reaction system, an aqueous solution obtained by dissolving 60 parts by mass of magnesium chloride hexahydrate in 60 parts by mass of ion-exchanged water was added over 10 minutes, and after standing for 3 minutes, the temperature was raised. Starting, the temperature of the system was raised to 90 ° C. over 60 minutes, and the resin fine particles were associated with each other while maintaining the temperature of 90 ° C. to grow particles. While measuring the particle size of associated particles using “Multisizer 3 (Beckman Coulter)”, 40.2 parts by mass of sodium chloride was ion exchanged when the volume-based median diameter reached 5.5 μm. An aqueous solution dissolved in 1,000 parts by mass of water was added to the reaction system to stop particle growth, thereby forming core particles [1].

(B) Formation of shell layer Next, 550 parts by mass (in terms of solid content) of the dispersion of the core particle [1] is set to 90 ° C., and the styrene-acrylic copolymer resin fine particle dispersion [B] is 50 mass. An aqueous solution obtained by dissolving 60 parts by mass of magnesium chloride hexahydrate in 60 parts by mass of ion-exchanged water was added over 10 minutes while stirring the reaction system. Stirring was continued over time to fuse the styrene-acrylic copolymer resin fine particles [B] onto the surface of the core particles [1]. Thereafter, an aqueous solution prepared by dissolving 40.2 parts by mass of sodium chloride in 1,000 parts by mass of ion-exchanged water was added. The system was heated to 95 ° C. and stirred for 20 minutes to age, a shell layer was formed, and after cooling to 30 ° C., the solid content was filtered and washed repeatedly with ion-exchanged water at 35 ° C. Then, the toner base particles [1B] having a structure in which the surface of the core particles [1] is coated with the shell layer were produced by drying with 40 ° C. hot air.

(5) Addition of external additive To 100 parts by mass of the obtained toner base particles [1B], 0.6 part by mass of hydrophobic silica (number average primary particle size = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (Number average primary particle size = 20 nm, hydrophobization degree = 63) 1.0 part by mass was added, and the rotary blade peripheral speed was 35 mm / sec at 32 ° C. for 20 minutes using a “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.). After mixing, a toner was manufactured by applying an external additive treatment to remove coarse particles using a sieve having an opening of 45 μm. The obtained toner (toner particles) had an average particle diameter (volume-based median diameter) of 6.5 μm and an average circularity of 0.945. The average particle diameter and the average circularity were measured by the same method as described in the above section (Toner physical properties).

<Preparation of two-component developer>
[Example 1]
100 parts by mass of “Carrier 1” prepared above and 6 parts by mass of “Toner” were mixed for 5 minutes with a V-type mixer to prepare a two-component developer 1.

[Example 2]
A two-component developer 2 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 2”.

[Example 3]
A two-component developer 3 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 3”.

[Example 4]
A two-component developer 4 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 4”.

[Example 5]
A two-component developer 5 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 5”.

[Comparative Example 1]
A two-component developer 6 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 6”.

[Comparative Example 2]
A two-component developer 7 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 7”.

[Comparative Example 3]
A two-component developer 8 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 8”.

[Comparative Example 4]
A two-component developer 9 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 9”.

[Comparative Example 5]
A two-component developer 10 was prepared in the same manner as in Example 1 except that “Carrier 1” was changed to “Carrier 10”.

<Evaluation of two-component developer>
A commercially available copier “bizhub C 6500” (manufactured by Konica Minolta Co., Ltd.) was prepared as a two-component developer evaluation apparatus, and the two-component developer prepared above was sequentially loaded to print 500,000 sheets. .

  The printing was performed on 500,000 A4 size transfer papers with a 3% printing rate in an environment of normal temperature and humidity (20 ° C., 50% RH).

[Chargeability evaluation]
Under normal temperature and humidity conditions (20 ° C, 50% RH) (NN), measure the amount of charge after the initial print and 500,000 prints, and charge from the difference between the initial print and 500,000 prints (ΔQ / M) Evaluated. The charge amount is a value obtained by the following blow-off method.

  The measurement of the charge amount by the blow-off method was performed using a blow-off charge amount measuring device “TB-200 (manufactured by Kyocera Chemical Co., Ltd.)”. The two-component developer to be measured was set in the charge amount measuring device equipped with a 400 mesh stainless steel screen, and blown with nitrogen gas for 10 seconds under the condition of a blow pressure of 50 kPa, and the charge was measured. The charge amount (μC / g) was calculated by dividing the measured charge by the flying toner mass.

If the difference in charge between the initial stage and the end of printing 500,000 sheets is 5 μC / g or less, there is no problem.
A: 1 to 3 μC / g
○: More than 3 μC / g and not more than 5 μC / g ×: More than 5 μC / g

[Carrier adhesion evaluation]
After making 500,000 copies, an A3 size blank original was copied and the output image was observed. The number of adhered carrier particles observed on the output image is visually measured using a magnifying glass. If the number of adhered carrier particles is 2 or less per A3 paper, ○, if more than 2 X was judged.

  The evaluation results are shown in Table 2. The two-component developer containing the carrier (carriers 1 to 5) according to the present invention showed good chargeability even after printing 500,000 sheets and hardly caused the carrier to adhere to the output image.

Claims (8)

A carrier for developing an electrostatic image having a resin coating layer on the surface of the core particle,
The resin coating layer includes a structural unit derived from an alicyclic (meth) acrylic acid ester monomer and at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group, a hydroxyl group, and an epoxy group. A resin containing a structural unit derived from a polymerizable monomer and a structure derived from a crosslinking agent that forms a crosslinked structure with the reactive functional group, and the core particles and the resin coating from the carrier surface A carrier for developing an electrostatic image, in which the degree of crosslinking gradually increases toward the interface with the layer.   2. The resin coating layer 1 having a crosslinked structure on the surface of the core material particle, and the resin coating layer 2 having a lower degree of crosslinking than the resin coating layer 1 on the outside of the resin coating layer 1. A carrier for developing electrostatic images.   The static crosslinking agent according to claim 1 or 2, wherein the crosslinking agent is at least one selected from the group consisting of a polyfunctional epoxy compound, a polyfunctional isocyanate compound, a polyfunctional carboxylic acid compound, a polyfunctional amine compound, and a carbodiimide compound. Carrier for developing charge image.   The static monomer according to any one of claims 1 to 3, wherein the polymerizable monomer is (meth) acrylic acid or a chain-type or branched-type (meth) acrylic acid ester having the reactive functional group. Carrier for developing charge image.   The electrostatic charge image developing carrier according to any one of claims 1 to 4, wherein the resin coating layer contains at least one element selected from the group consisting of nitrogen, phosphorus and sulfur.   A two-component developer comprising the electrostatic charge image developing carrier according to claim 1 and an electrostatic charge developing toner.   The two-component developer according to claim 6, wherein the electrostatic charge developing toner contains a crystalline resin and has a volume-based median diameter of 3 to 10 μm. After the resin particles 1 are attached to the surface of the core material particles, the resin particles 1 are crosslinked by heating to form the resin coating layer 1,
Including attaching the resin particles 2 to the surface of the resin coating layer 1 and crosslinking the resin particles 2 by heating to form the resin coating layer 2;
The resin particle 1 and the resin particle 2 are at least one selected from the group consisting of a structural unit derived from an alicyclic (meth) acrylic acid ester monomer, and a carboxyl group, an amino group, a hydroxyl group, and an epoxy group. A resin containing a structural unit derived from a polymerizable monomer having a reactive functional group; and a crosslinking agent that forms a cross-linked structure with the reactive functional group. A method for producing a carrier for developing an electrostatic image, wherein the content of the crosslinking agent is large.