JP6003717B2 - Method for producing toner for developing electrostatic image - Google Patents

Description

  The present invention relates to a method for producing a toner for developing an electrostatic charge image used for electrophotographic image formation.

Conventionally, in an electrophotographic image forming method, as a method of fixing a toner image formed with an electrostatic charge image developing toner (hereinafter also simply referred to as “toner”) on an image recording sheet such as paper, for example, A heat roller fixing method is widely used in which an image recording sheet on which a toner image is formed is fixed by heat and pressure by passing between a heating roller and a pressure roller arranged in pressure contact with each other. ing. The heating roller used in this heat roller fixing method is required to generate a certain amount of heat in order to secure fixing property, that is, adhesion of toner to the image recording sheet.
However, in recent years, in response to a request for measures to prevent global warming, electrophotographic image forming apparatuses adopting a heat roller fixing method have been required to save energy, and in order to meet such demands. Technology for reducing the amount of heat required for fixing is being studied. For example, by using a combination of a crystalline resin and an amorphous resin as a binder resin constituting the toner, the low-temperature fixability of the toner is improved. Techniques to make it have been proposed.

  As a toner using a combination of a crystalline resin and an amorphous resin as a binder resin, for example, a fine emulsion containing an amorphous resin together with a crystalline resin using miniemulsion polymerization is used as a colorant fine particle or a release agent. Produced by agglomerating with fine particles (see Patent Document 1), or produced by agglomerating fine particles obtained by coating a crystalline resin with an amorphous resin together with colorant fine particles and release agent fine particles using seed polymerization (See Patent Documents 2 and 3).

However, in the toner disclosed in Patent Document 1, since it is necessary to go through a step of once dissolving the crystalline resin, the amount of the crystalline resin that can be contained in the toner particles is limited to a small amount. As the polymerization of the amorphous resin proceeds while the crystalline resin is dissolved or melted, crystallization is hindered by entering the amorphous resin between the molecular chains. There is a problem that it becomes in a state of being converted into a heat-resistant storage property.
Further, in the toners disclosed in Patent Documents 2 and 3, since the resin fine particles are aggregated with the fine particles made of only the release agent, the surface properties of the fine particles made of only the resin fine particles and the release agent are different. In this case, the dispersibility of the colorant is adversely affected, and the dispersibility of the colorant in the resulting toner particles is low.As a result, sufficient image density and saturation cannot be obtained, and when carbon black is used as the colorant. Has a problem that charging failure and transfer failure occur.
These problems become significant when the content of the crystalline polyester is increased in order to improve the low-temperature fixability.

JP 2002-049180 A JP 2006-267732 A JP 2011-197659 A

  The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a method for producing a toner for developing an electrostatic image that is excellent in dispersibility of a colorant and can obtain a sufficient image density. There is to do.

The method for producing a toner for developing an electrostatic charge image of the present invention comprises a toner particle comprising a binder resin containing a crystalline polyester and an amorphous vinyl polymer, a colorant, and a release agent. A method for producing a toner for developing a charge image, comprising:
It has at least the following steps (a) to (c).
(A) Step of producing resin fine particles (M) made of vinyl polymer A containing a release agent (b) A vinyl monomer is added to an aqueous medium in which crystalline polyester fine particles are dispersed, Step of producing resin fine particles (S) in which the crystalline polyester fine particles are coated with the vinyl polymer B by performing seed polymerization with the vinyl monomer using the crystalline polyester fine particles as seed particles (c) A step of agglomerating and fusing the resin fine particles (M), the resin fine particles (S), and the colorant fine particles in an aqueous medium.

  In the method for producing an electrostatic charge image developing toner of the present invention, it is preferable that the resin fine particles (M) are formed by forming an outermost layer composed only of the vinyl polymer A.

  In the method for producing a toner for developing an electrostatic charge image of the present invention, in the step (c), after adding an aggregating agent to an aqueous medium in which the resin fine particles (M) and the colorant fine particles are dispersed, It is preferable to add the resin fine particles (S) to the aqueous medium.

  In the method for producing a toner for developing an electrostatic charge image of the present invention, a shell layer is formed by agglomerating and fusing fine particles of an amorphous resin on the surface of the associated particles obtained by performing the step (c). It is preferable to perform the shelling step to be formed.

  According to the method for producing a toner of the present invention, resin fine particles (M) made of a vinyl polymer A containing a release agent, and resin fine particles (S) in which crystalline polyester fine particles are coated with a vinyl polymer B. By aggregating the colorant fine particles, an electrostatic charge image developing toner that is excellent in dispersibility of the colorant and can obtain a sufficient image density can be produced.

  Hereinafter, the present invention will be specifically described.

[Toner Production Method]
The toner production method of the present invention is a method for producing a toner comprising toner particles containing a binder resin containing a crystalline polyester and an amorphous vinyl polymer, a colorant, and a release agent. A resin fine particle (M) comprising at least a vinyl polymer A containing a release agent, a resin fine particle (S) in which crystalline polyester fine particles are coated with a vinyl polymer B, and a colorant fine particle. It is a method characterized by having the process of making it aggregate.

In the present invention, resin fine particles (M) made of vinyl polymer A containing a release agent, resin fine particles (S) in which crystalline polyester fine particles are coated with vinyl polymer B, colorant fine particles, By agglomerating the toner particles, toner particles having excellent colorant dispersibility can be produced.
The reason is that the surface properties of the resin fine particles (M) and the resin fine particles (S) are approximated, and excellent affinity is obtained between the resin fine particles (M) and the resin fine particles (S). It is assumed that
Specifically, when toner particles are produced using a so-called association method, the uneven distribution of the colorant in the toner particles is caused by the formation of low-polarity domains and high-polarity domains in the aggregated particles during aggregation. It is thought that there is. That is, since the colorant generally has both a polar part and a nonpolar part, if a domain having a low polarity and a domain having a high polarity are present at the time of aggregation, the colorant fine particles are arranged along the interface. In addition, certain vinyl polymers such as styrene acrylic resin generally used as a binder resin for toners form domains with high polarity, release agents form domains with low polarity, and crystalline polyesters are also polar. It is easy to form a low domain. Accordingly, when the fine particles of vinyl polymer, the fine particles consisting only of the release agent, the crystalline polyester fine particles, and the colorant fine particles are aggregated, the dispersibility of the colorant fine particles becomes low. As a result, since the dispersibility of the colorant in the obtained toner particles is low, a sufficient image density and saturation cannot be obtained in the color toner, and a sufficient image density cannot be obtained in the black toner. In the black toner using carbon black as the carbon black lined up at the interface, a conduction path having a low electrical resistance is formed, resulting in charging failure and transfer failure.
However, in the present invention, the crystalline polyester is used for agglomeration as fine particles coated with a vinyl polymer, and the release agent is used for agglomeration as fine particles contained in the vinyl polymer, so that the resin fine particles (M) And a high affinity between the resin fine particles (S), and therefore, formation of domains with low polarity and domains with high polarity is suppressed, and therefore, good dispersibility of the colorant fine particles during aggregation can be obtained. As a result, uneven distribution of the colorant in the obtained toner particles can be suppressed.

  In the present invention, the “aqueous medium” refers to a medium comprising 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and it is preferable to use an organic solvent that does not dissolve each resin fine particle.

An example of a method for producing the toner of the present invention is specifically shown as follows:
(A) a resin fine particle (M) containing a release agent, which produces resin fine particles (M) comprising a vinyl polymer A containing a release agent;
(B) Crystallinity is obtained by adding vinyl monomer β to an aqueous medium in which crystalline polyester fine particles are dispersed and performing seed polymerization with vinyl monomer β using the crystalline polyester fine particles as seed particles. A resin fine particle (S) production step containing crystalline polyester, which produces a resin fine particle (S) in which a polyester fine particle is coated with a vinyl polymer B,
(C) an agglomeration / fusion process for aggregating and fusing the resin fine particles (M), the resin fine particles (S) and the colorant fine particles in an aqueous medium to form associated particles;
(D) an aging step of aging associated particles with thermal energy to control the shape and obtaining toner particles;
(E) a cooling step for cooling the dispersion of toner particles;
(F) a filtration / washing step of filtering toner particles from the aqueous medium and removing the surfactant from the toner particles;
(G) a drying step of drying the washed toner particles;
(H) It can be added as needed to the steps (a) to (c) essential to the present invention, such as an external additive addition step of adding an external additive to the dried toner particles (d). (H) What consists of a process can be mentioned.

(A) Production process of resin fine particles (M) containing a release agent In this production process of resin fine particles (M), resin fine particles (M) containing a vinyl polymer A as a main component and containing a release agent are produced. Is done. As an example of the method for producing the resin fine particles (M), a method of producing by a miniemulsion polymerization method using a vinyl monomer α for obtaining the vinyl polymer A can be mentioned. That is, for example, a monomer mixed solution of vinyl monomer α in which a release agent is dissolved or dispersed in an aqueous medium containing a surfactant is added, and mechanical energy is applied to form droplets. Subsequently, the polymerization reaction is advanced in the droplets by radicals from the water-soluble radical polymerization initiator. Note that an oil-soluble polymerization initiator may be contained in the droplet. Thereby, the resin fine particles (M) containing the vinyl polymer A as a main component and containing a release agent can be produced.
The resin fine particles (M) are preferably formed by forming an outermost layer composed only of the vinyl polymer A. Since the resin fine particles (M) have such a structure, the surface properties of the resin fine particles (M) and the resin fine particles (S) are further improved by making the release agent not exist on the particle surface. Thus, the affinity between the resin fine particles (M) and the resin fine particles (S) can be made higher.
The resin fine particles (M) in which the outermost layer composed only of the vinyl polymer A is formed, for example, in an aqueous medium in which the release agent fine particles are dispersed, with the release agent fine particles as seed particles. The seed particles are resin fine particles containing a mold release agent prepared by the above-mentioned miniemulsion polymerization method or a method of forming the outermost layer by seed polymerization of vinyl-based monomer α on the release agent fine particles. Further, it can be produced by a multi-stage polymerization method in which the outermost layer is formed by seed polymerization of the vinyl monomer α on the resin fine particles containing the release agent. In particular, since a release agent having a low melt viscosity can be used, it is preferable to prepare by a multistage polymerization method. In the resin fine particles (M) in which the outermost layer composed only of the vinyl polymer A is formed, the polymer constituting the inner layer other than the outermost layer is not of the same composition as the vinyl polymer A. May be.

As the vinyl monomer α for obtaining the vinyl polymer A, the following can be used. The following vinyl monomers can be used alone or in combination of two or more as the vinyl monomer α.
(1) Styrene monomer Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert -Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, and derivatives thereof.
(2) (meth) acrylic acid ester monomer (meth) methyl acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, T-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, phenyl (meth) acrylate, (meth ) Diethylaminoethyl acrylate, dimethylaminoethyl (meth) acrylate, and derivatives thereof.
(3) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate and the like.
(4) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether and the like.
(5) Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone and the like.
(6) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone and the like.
(7) Others Vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

As the vinyl monomer α for obtaining the vinyl polymer A, it is preferable to use a monomer having an ionic dissociation group such as a carboxy group, a sulfonic acid group, or a phosphoric acid group. Specifically, there are the following.
Examples of the monomer having a carboxy group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, and the like. Examples of the monomer having a sulfonic acid group include styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, and the like. Furthermore, examples of the monomer having a phosphate group include acid phosphooxyethyl methacrylate.
The ratio of the monomer having an ionic dissociation group in all vinyl monomers α is preferably 2 to 10% by mass. If the proportion of the monomer having an ionic dissociation group is excessive, the amount of moisture adsorbed on the surface of the toner particles may increase, which may cause generation of toner blisters or expansion of the difference in charge amount environment.

  Furthermore, as the vinyl monomer α for obtaining the vinyl polymer A, polyfunctional vinyls may be used, and the vinyl polymer A may have a crosslinked structure. Polyfunctional vinyls include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol Examples include diacrylate.

  As the vinyl polymer A, for example, a styrene acrylic resin obtained by copolymerizing at least a styrene monomer and a (meth) acrylate monomer is preferable.

〔Release agent〕
Various known waxes can be used as the release agent.
As the wax, polyolefin waxes such as low molecular weight polypropylene, polyethylene, or oxidized polypropylene, polyethylene, and ester waxes such as behenate behenate can be preferably used.
Specifically, polyolefin waxes such as polyethylene wax and polypropylene wax; branched hydrocarbon waxes such as microcrystalline wax; long-chain hydrocarbon waxes such as paraffin wax and sazol wax; dialkyls such as distearyl ketone Ketone wax; carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanedioldi Ester wax such as stearate, trimellitic trimellitic acid, distearyl maleate; ethylenediamine behenylamide, trimellitic acid tristearylamide Such as amide waxes.
Among these, from the viewpoint of releasability during low-temperature fixing, it is preferable to use those having a low melting point, specifically, those having a melting point of 40 to 90 ° C.

  The content of the release agent contained in the resin fine particles (M) is preferably 5 to 20% by mass. When the content ratio of the release agent contained in the resin fine particles (M) is in the above range, both the separation property and the fixing property can be reliably obtained. If the content of the release agent is too small, the separability is low, and there is a concern that the fixing member may be wound around the fixing member or the toner may adhere to the fixing member and a hot offset phenomenon may occur. When the content ratio of the release agent is excessive, the fixing property is lowered due to an increase in the amount of heat absorbed by the release agent, or an inhibition of the adhesion between the image recording sheet and the binder resin. There is a risk that filming may occur in the photosensitive member or the intermediate transfer member due to the generation of the free release agent.

  In the toner particles according to the present invention, the content ratio of the release agent is usually preferably 0.5 to 25 parts by mass, more preferably 3 to 15 parts by mass with respect to 100 parts by mass of the binder resin. When the content ratio of the release agent in the toner particles is in the above range, both the separation property and the fixing property can be reliably obtained.

[Surfactant]
As the surfactant, conventionally known various anionic surfactants, cationic surfactants, nonionic surfactants and the like can be used.

(Polymerization initiator)
Various conventionally known polymerization initiators can be used. As specific examples of the polymerization initiator, for example, persulfates (potassium persulfate, ammonium persulfate, etc.) are preferably used. In addition, azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salts, etc.), peroxide compounds, azobisisobutyronitrile, etc. Also good.

[Chain transfer agent]
In the resin fine particle (M) preparation step, a chain transfer agent generally used can be used for the purpose of adjusting the molecular weight of the vinyl polymer A. The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, and t-dodecyl mercaptan, and styrene dimers.

The toner particles according to the present invention may contain other internal additives such as a charge control agent, if necessary, in addition to the binder resin, the colorant, and the release agent. In this resin fine particle (M) preparation step, for example, the additive may be introduced into the toner particles by dissolving or dispersing in advance in a monomer mixture for forming the vinyl polymer A. it can.
In addition, such an internal additive is prepared by separately preparing a dispersion of internal additive fine particles composed solely of the internal additive, and together with the resin fine particles (M), the resin fine particles (S) and the colorant fine particles in the aggregation / fusion process. The internal additive fine particles can be introduced into the toner particles by aggregating, but it is preferable to adopt a method of introducing them in advance in the resin fine particle (M) preparation step.

[Charge control agent]
When the charge control agent is contained in the toner particles, various known compounds can be used as the charge control agent.
The content ratio of the charge control agent in the toner particles is usually 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the finally obtained binder resin. .

The average particle diameter of the resin fine particles (M) is preferably in the range of 50 to 400 nm in terms of volume-based median diameter.
The volume-based median diameter of the resin fine particles (M) is measured using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

  The resin fine particles (M) preferably have a weight average molecular weight of 10,000 to 150,000 and a number average molecular weight of 5,000 to 50,000 as measured by gel permeation chromatography (GPC). .

  Specifically, the measurement of the weight average molecular weight by gel permeation chromatography (GPC) is performed using the apparatus “HLC-8120GPC” (manufactured by Tosoh Corporation) and the column “TSKguardcolumn + TSKgelSuperHZ-M3 series” (manufactured by Tosoh Corporation), and the column temperature. While maintaining at 40 ° C., tetrahydrofuran (THF) as a carrier solvent is allowed to flow at a flow rate of 0.2 ml / min, and the measurement sample (resin fine particles (M)) is treated at room temperature for 5 minutes using an ultrasonic disperser. The sample solution was dissolved in tetrahydrofuran so as to have a concentration of 1 mg / ml under conditions, and then treated with a membrane filter having a pore size of 0.2 μm to obtain a sample solution. Detection using rate detector (RI detector) The molecular weight distribution of the measurement sample is calculated using a calibration curve measured using a monodisperse polystyrene standard sample. Ten polystyrenes were used for calibration curve measurement.

(B) Production process of resin fine particles (S) containing crystalline polyester In this production process of resin fine particles (S), resin fine particles (S) in which crystalline polyester fine particles are coated with a coating layer of vinyl polymer B are used. Make it. Specifically, vinyl monomer β and a polymerization initiator are added to an aqueous medium in which crystalline polyester fine particles are dispersed, and seed polymerization with vinyl monomer β is performed using the crystalline polyester fine particles as seed particles. By carrying out, resin fine particles (S) are produced.

As the vinyl monomer β, those exemplified as the vinyl monomer α for forming the vinyl polymer A constituting the resin fine particles (M) containing the above releasing agent can be used. . The above vinyl monomers can be used alone or in combination of two or more as the vinyl monomer β.
In the present invention, the vinyl polymer B constituting the resin fine particles (S) and the vinyl polymer A constituting the outermost layer of the resin fine particles (M) are polymerized from the same kind of monomers. It is preferable that the vinyl polymer B constituting the resin fine particles (S) and the vinyl polymer A constituting the outermost layer of the resin fine particles (M) have the same composition. For this reason, as the vinyl monomer β, the same type of vinyl monomer α used to form the vinyl polymer A constituting the outermost layer of the resin fine particles (M) is used in the same ratio. It is preferable to do. Since the vinyl polymer B constituting the resin fine particles (S) and the vinyl polymer A constituting the outermost layer of the resin fine particles (M) have the same composition, the resin The surface properties of the fine particles (M) and the resin fine particles (S) can be made more approximate, and the affinity between the resin fine particles (M) and the resin fine particles (S) should be higher. Can do.
The vinyl monomer β preferably includes at least a monomer having a carbonyl group. Preferred monomers having a carbonyl group include (meth) acrylate monomers and those having an ionic dissociation group such as a carboxy group. Preferable (meth) acrylic acid ester monomers include methyl methacrylate or butyl acrylate, 2-ethylhexyl acrylate and the like. Moreover, as a monomer which has a preferable carboxy group, methacrylic acid, acrylic acid, etc. are mentioned. By using a monomer having a carboxy group as the vinyl monomer β, since the monomer having the carboxy group has a high polarity, a coating layer of the vinyl polymer B can be easily formed on the surface of the crystalline polyester fine particles. can do.
The ratio of the monomer having an ionic dissociation group in all vinyl monomers β is preferably 2 to 10% by mass. If the proportion of the monomer having an ionic dissociation group is excessive, the amount of moisture adsorbed on the surface of the toner particles may increase, which may cause generation of toner blisters or expansion of the difference in charge amount environment.

  As the vinyl polymer B, for example, a styrene acrylic resin obtained by copolymerizing at least a styrene monomer and a (meth) acrylate monomer is preferable.

(Crystalline polyester)
The crystalline polyester constituting the crystalline polyester fine particles is a known polyester obtained by a polycondensation reaction between a divalent or higher carboxylic acid compound (polyhydric carboxylic acid compound) and a divalent or higher alcohol compound (polyhydric alcohol compound). Among polyester resins, in differential scanning calorimetry (DSC), it refers to a resin having a clear endothermic peak rather than a stepwise endothermic change. The clear endothermic peak specifically means a peak in which the 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 polyvalent carboxylic acid compound is a compound containing two or more carboxy groups in one molecule.
Specifically, for example, saturated aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, and n-dodecyl succinic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid Acids; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid; and anhydrides of these carboxylic acid compounds or 1 to 3 carbon atoms And alkyl esters thereof.
These may be used individually by 1 type and may be used in combination of 2 or more type.

A polyhydric alcohol compound is a compound containing two or more hydroxyl groups in one molecule.
Specifically, for example, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, Aliphatic diols such as 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, 1,4-butenediol; glycerin, pentaerythritol, tri Examples include trihydric or higher polyhydric alcohols such as methylolpropane and sorbitol.
These may be used individually by 1 type and may be used in combination of 2 or more type.

As the crystalline polyester, it is preferable to use a polyester having a melting point of 40 to 100 ° C, more preferably 60 to 90 ° C.
When the melting point of the crystalline polyester is in the above range, sufficient low-temperature fixability and excellent hot offset resistance can be obtained. On the other hand, when the melting point of the crystalline polyester is excessively low, the obtained toner has a low thermal strength, and there is a possibility that sufficient heat resistant storage stability and hot offset resistance cannot be obtained. Moreover, when the melting point of the crystalline polyester is excessively high, sufficient low-temperature fixability may not be obtained.

  Here, the melting point of the crystalline polyester is specifically the first temperature rising from 0 ° C. to 200 ° C. at a raising / lowering speed of 10 ° C./min using a differential scanning calorimeter “Diamond DSC” (manufactured by Perkin Elmer). Measurement conditions for passing through a temperature raising process, a cooling process for cooling from 200 ° C. to 0 ° C. at a cooling rate of 10 ° C./min, and a second temperature raising process for raising the temperature from 0 ° C. to 200 ° C. at a lifting speed of 10 ° C./min. Based on the DSC curve obtained by this measurement, the endothermic peak top temperature derived from the crystalline polyester in the first temperature raising process is taken as the melting point. . As a measuring procedure, 3.0 mg of crystalline polyester is sealed in an aluminum pan and set in a diamond DSC sample holder. The reference used an empty aluminum pan.

As for the molecular weight measured by the gel permeation chromatography (GPC) of crystalline polyester, it is preferable that a weight average molecular weight is 5,000-50,000 and a number average molecular weight is 1,500-25,000.
The molecular weight measured by gel permeation chromatography (GPC) of the crystalline polyester is measured in the same manner as described above except that the crystalline polyester is used as a measurement sample.

  The content of the crystalline polyester contained in the resin fine particles (S) is preferably 20 to 90% by mass. When the content of the crystalline polyester contained in the resin fine particles (S) is in the above range, the crystalline polyester is not exposed on the surface of the resin fine particles (S), and low temperature fixability can only be achieved. The amount of crystalline polyester can be introduced into the toner particles. When the content ratio of the crystalline polyester is too small, there is a possibility that sufficient introduction of the crystalline polyester into the toner particles cannot be obtained and sufficient low-temperature fixing cannot be achieved. When the content of the crystalline polyester is excessive, the crystalline polyester may be exposed on the surface of the resin fine particles (S), and as a result, the affinity between the resin fine particles (M) and the resin fine particles (S). Therefore, the dispersibility of the colorant in the toner particles may be lowered.

  In the toner particles according to the present invention, the content ratio of the crystalline polyester constituting the binder resin is preferably 2 to 30% by mass. When the content of the crystalline polyester in the toner particles is in the above range, sufficient low-temperature fixability and excellent hot offset resistance can be obtained. Further, if the content of the crystalline polyester is too small, sufficient low-temperature fixability may not be obtained. If the content of the crystalline polyester is excessive, hot offset resistance may not be obtained.

The average particle diameter of the crystalline polyester fine particles serving as seed particles is preferably in the range of 10 to 280 nm in terms of volume-based median diameter.
The volume-based median diameter of the crystalline polyester fine particles is measured using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

  A surfactant may be contained in the aqueous medium. As surfactant, the thing similar to what was mentioned in the resin fine particle (M) preparation process containing said mold release agent can be mentioned.

  For seed polymerization, a generally used chain transfer agent can be used for the purpose of adjusting the molecular weight of the vinyl polymer B. Examples of the chain transfer agent include the same ones as mentioned in the resin fine particle (M) preparation step containing the release agent.

  As a polymerization initiator, the thing similar to what was mentioned in the resin fine particle (M) preparation process containing said mold release agent can be mentioned.

  The seed polymerization is preferably performed in a state where the viscosity of the crystalline polyester is high, and the polymerization temperature of the seed polymerization is preferably the melting point of the crystalline polyester + 20 ° C. or less, more preferably the melting point + 10 ° C. or less. More preferably, it is below the melting point.

The average particle diameter of the resin fine particles (S) is preferably in the range of 20 to 400 nm in terms of volume-based median diameter.
The volume-based median diameter of the resin fine particles (S) is measured using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

The resin fine particles (S) preferably have a weight average molecular weight of 8,000 to 60,000 and a number average molecular weight of 3,500 to 35,000 as measured by gel permeation chromatography (GPC). .
The molecular weight of the resin fine particles (S) measured by gel permeation chromatography (GPC) is measured in the same manner as described above except that the resin fine particles (S) are used as measurement samples.

(C) Aggregation / fusion process In the aggregation / fusion process, the resin fine particles (M), the resin fine particles (S) and the colorant fine particles, and if necessary, fine particles of other toner constituents are aggregated, This is a step of fusing by heating. Specifically, an aggregating agent having a critical aggregation concentration or higher is added to an aqueous medium in which these fine particles are dispersed so that the glass transition point of the vinyl polymer A and the vinyl polymer B is higher than that. Put on.

In the present invention, after adding the flocculant to the aqueous medium in which the resin fine particles (M) and the colorant fine particles are dispersed in a state below the glass transition point of the vinyl polymer A and the vinyl polymer B, The resin fine particles (S) are preferably added to the aqueous medium. In particular, the resin fine particles (S) at a point before the particles formed by agglomeration of the resin fine particles (M) and the colorant fine particles are fused. Is preferably added to the aqueous medium and then aggregated and fused by raising the temperature to a glass transition point or higher of the vinyl polymer A and the vinyl polymer B.
Even if there is a slight difference in the surface properties of the resin fine particles (M) and the resin fine particles (S) by adding the resin fine particles (S) at this timing and subjecting them to aggregation, the colorant fine particles in the aggregated particles It is considered that the dispersibility of can be reliably increased. Further, since the crystalline polyester can be uniformly present in the obtained toner particles, the plasticization of the binder resin can be promptly and uniformly promoted at the time of heat fixing, and as a result, excellent low temperature fixability can be obtained. can get.

  The fusing temperature for fusing the resin fine particles (M) and the resin fine particles (S) may be at least the glass transition point of the vinyl polymer A and the vinyl polymer B. Glass transition point of polymer A and vinyl polymer B + 10 ° C.) to (glass transition point of vinyl polymer A and vinyl polymer B + 70 ° C.), particularly preferably (vinyl polymer A and vinyl polymer B and vinyl polymer B). The glass transition point of the polymer B is + 35 ° C.) to (the glass transition point of the vinyl polymer A and the vinyl polymer B + 60 ° C.).

[Flocculant]
The flocculant is not particularly limited, but a flocculant selected from metal salts such as alkali metal salts and alkaline earth metal salts is preferably used. Examples of the metal salt include monovalent metal salts such as sodium, potassium, and lithium; divalent metal salts such as calcium, magnesium, manganese, and copper; and trivalent metal salts such as iron and aluminum. Specific metal salts can include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, and the like. It is particularly preferable to use a divalent metal salt. These can be used individually by 1 type or in combination of 2 or more types.

The colorant fine particles are preferably subjected to this aggregation / fusion step as a dispersion in which the colorant fine particles are dispersed in an aqueous medium.
A dispersion of colorant fine particles is obtained by dispersing a colorant in an aqueous medium in which a surfactant is added to a critical micelle concentration (CMC) or higher.
The disperser used for dispersing the colorant is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gourin or a pressure homogenizer, a sand grinder, a Getzmann mill, a diamond fine mill, etc. And a medium type dispersing machine.
The average particle diameter of the colorant fine particles in the dispersion of the colorant fine particles is preferably in the range of, for example, 10 to 300 nm as a volume-based median diameter. The volume-based median diameter is measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

[Colorant]
As the colorant, various known colorants such as carbon black, black iron oxide, dye, and pigment can be used.
Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Examples of black iron oxide include magnetite, hematite, and iron iron trioxide.
Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 and the like.
Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 150, 166, 177, 178, 222, 238, 269, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 74, 93, 94, 138, 155, 156, 158, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, and the like.
The colorant for obtaining the toner of each color can be used singly or in combination of two or more for each color.

As the colorant, a surface-modified one can also be used. As the surface modifier, conventionally known ones can be used, and specifically, silane coupling agents, titanium coupling agents, aluminum coupling agents and the like can be preferably used.
Specifically, a colorant is dispersed in a solvent, a surface modifier is added, the system is reacted by raising the temperature, and after completion of the reaction, the colorant is filtered and washed with the same solvent, After repeated filtration, the surface-modified colorant can be obtained by drying.

  The content of the colorant is preferably 1 to 15% by mass in the toner particles, and more preferably 3 to 10% by mass. If the content of the colorant is too small, the resulting toner may not have the desired coloring power. On the other hand, if the content of the colorant is excessive, it may be released to the colorant or to the carrier. May occur, which may affect the chargeability.

(D) Aging process The aging process is performed as necessary, and in the aging process, the associated particles obtained by the aggregation / fusion process are aged by heat energy until a desired shape is obtained. An aging process for forming toner particles is performed.
Specifically, the aging treatment is performed by adjusting the heating temperature, stirring speed, heating time, and the like until the shape of the associated particles reaches a desired circularity by heating and stirring the system in which the associated particles are dispersed. Done.

(E) Cooling Step This cooling step is a step of cooling the toner particle dispersion. As a condition for the cooling treatment, it is preferable to cool at a cooling rate of 1 to 20 ° C./min. The specific method of the cooling treatment is not particularly limited, and examples include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, a method of cooling by directly introducing cold water into the reaction system, and the like. it can.

(F) Filtration / Washing Step This filtration / washing step involves solid-liquid separation of the toner particles from the cooled dispersion of toner particles, and a toner cake obtained by solid-liquid separation (the toner particles in a wet state are caked). This is a step of removing adhering substances such as a surfactant and an aggregating agent from the aggregate).
The solid-liquid separation is not particularly limited, and a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press, or the like can be used. Further, in washing, it is preferable to wash with water until the electric conductivity of the filtrate reaches 10 μS / cm.

(G) Drying Step This drying step is a step of drying the washed toner cake, and can be performed in accordance with a drying step in a generally-known method for producing toner particles.
Specifically, examples of the dryer used for drying the toner cake include a spray dryer, a vacuum freeze dryer, and a vacuum dryer, and a stationary shelf dryer, a mobile shelf dryer, a fluidized bed, and the like. It is preferable to use a dryer, a rotary dryer, a stirring dryer or the like.
The moisture of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the dried toner particles are aggregated by a weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(H) External additive addition step The above toner particles can be used as toners as they are. However, in order to improve fluidity, chargeability, cleaning properties, etc., so-called fluidizing agents and cleaning aids are added to the toner particles. You may use it in the state which added external additives, such as an agent.
Various external additives may be used in combination.
The total addition amount of these external additives is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner particles.
As the external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

[Toner glass transition point]
The toner according to the present invention preferably has a glass transition point (Tg) of 15 to 50 ° C, more preferably 20 to 45 ° C.
When the glass transition point of the toner is in the above range, sufficient low-temperature fixing property and heat-resistant storage property can be reliably achieved. When the glass transition point of the toner is too low, the heat resistance (thermal strength) of the toner is lowered, and there is a possibility that sufficient heat storage stability and hot offset resistance cannot be obtained. In addition, when the glass transition point of the toner is excessive, there is a possibility that sufficient low-temperature fixability cannot be obtained.

The glass transition point (Tg) of the vinyl polymer is measured using “Diamond DSC” (manufactured by PerkinElmer).
As a measurement procedure, 3.0 mg of a sample (toner) is sealed in an aluminum pan and set in a holder. The reference used an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Perform analysis based on the data in Heat, draw a baseline extension before the rise of the first endothermic peak, and a tangent line indicating the maximum slope between the rise of the first peak and the peak apex, The intersection point is shown as the glass transition point.

[Particle size of toner particles]
The average particle diameter of the toner is preferably 3 to 8 μm, and more preferably 5 to 8 μm, for example, on a volume basis median diameter. This average particle size can be controlled by the concentration of the flocculant used during production, the amount of organic solvent added, the fusing time, the composition of the binder resin, and the like.
When the volume-based median diameter is in the above range, a very small dot image of 1200 dpi level can be faithfully reproduced.

  The volume-based median diameter of the toner particles is measured and calculated using a measuring device in which “Multisizer 3” (manufactured by Beckman Coulter) is connected to a computer system equipped with data processing software “Software V3.51”. Is. Specifically, 0.02 g of toner is added to 20 mL of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). Then, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion, and this toner dispersion is placed in a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in a sample stand. Pipet until the indicated concentration is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measuring apparatus, the measurement particle count number is 25000, the aperture diameter is 100 μm, and the frequency value is calculated by dividing the range of 2 to 60 μm, which is the measurement range, into 256 parts. % Particle diameter is defined as the volume-based median diameter.

[Average circularity of toner particles]
The individual toner particles constituting the toner preferably have an average circularity of 0.930 to 1.000, preferably 0.950 to 0.995, from the viewpoint of stability of charging characteristics and low-temperature fixability. It is more preferable that
When the average circularity is within the above range, individual toner particles are less likely to be crushed, the contamination of the frictional charge imparting member is suppressed, the toner chargeability is stabilized, and the toner transferred to the image recording sheet The density of toner particles in the layer is increased, fixing property is improved, and fixing offset is less likely to occur.

The average circularity of the toner particles is a value measured using “FPIA-2100” (manufactured by Sysmex). Specifically, the toner is blended with an aqueous solution containing a surfactant, and subjected to ultrasonic dispersion treatment for 1 minute to disperse, and then measurement conditions HPF (high magnification imaging) are performed according to “FPIA-2100” (manufactured by Sysmex). ) Mode, photographing is performed at an appropriate density of 3,000 to 10,000 HPF detections, the circularity is calculated according to the following formula (y) for each toner particle, and the circularity of each toner particle is added. , A value calculated by dividing by the total number of toner particles. If the number of HPF detections is in the above range, reproducibility can be obtained.
Formula (y): Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

  According to the toner manufacturing method as described above, resin fine particles (M) made of vinyl polymer A containing a release agent, and resin fine particles (S) in which crystalline polyester fine particles are coated with vinyl polymer B are used. ) And the colorant fine particles can be used to produce a toner for developing an electrostatic charge image having excellent colorant dispersibility and sufficient image density or saturation.

(Developer)
The toner obtained as described above can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. When the toner is used as a two-component developer, the carrier includes magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead. In particular, ferrite particles are preferable. As the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a dispersion type carrier in which magnetic fine powder is dispersed in a binder resin, or the like may be used.
The volume-based median diameter of the carrier is preferably 20 to 100 μm, more preferably 25 to 80 μm. The volume-based median diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  Preferred carriers include a resin-coated carrier in which the surface of magnetic particles is coated with a resin, and a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. The resin constituting the resin-coated carrier is not particularly limited, and examples thereof include olefin resins, styrene resins, styrene-acrylic resins, acrylic resins, silicone resins, ester resins, and fluorine-containing polymer resins. Can be mentioned. Moreover, as resin which comprises a resin dispersion type carrier, it is not specifically limited, A well-known thing can be used, for example, acrylic resin, styrene-acrylic resin, polyester resin, fluorine resin, phenol resin etc. are used. can do.

Although the embodiments of the present invention have been specifically described above, the embodiments of the present invention are not limited to the above examples, and various modifications can be made.
For example, the method for producing a toner of the present invention is applied to the production of a toner comprising toner particles having a core-shell structure comprising a core particle containing a binder resin and a shell layer made of a shell resin covering the outer peripheral surface thereof. You can also.
According to the toner in which the shell layer is formed in this manner, the colorant is coated with the amorphous resin and is not exposed on the surface of the toner particle, so that the colorant is present on the surface of the toner particle. Occurrence of charging failure and the like can be suppressed.

  Here, the “core-shell structure” may be not only a form in which the shell layer completely covers the core particles but also a part of the core particles. Further, a part of the shell resin constituting the shell layer may form a domain or the like in the core particle. Furthermore, the shell layer may have a multilayer structure of two or more layers made of resins (amorphous resins) having different compositions.

The shell resin for forming the shell layer may be an amorphous resin, such as a styrene acrylic resin or an amorphous polyester resin.
As the shell resin, it is preferable to use a shell resin that is incompatible with the binder resin constituting the core particles and has a high glass transition point, specifically, for example, a temperature of 45 to 60 ° C.

  The toner particles having the core-shell structure are aqueous systems in which the aggregated particles obtained by performing the aggregation / fusion step (c) after the aggregation / fusion step (c) are used as core particles, and the core particles are dispersed. By adding fine particles of an amorphous resin into the medium and slowly aggregating and fusing the shell resin fine particles on the surface of the core particles over 1 to 7 hours with heating and stirring, a thickness of 100 to 300 nm is obtained. It can manufacture by performing the shell-forming process which forms a shell layer.

  In the toner particles having the core-shell structure, the content ratio of the shell resin constituting the shell layer is preferably 5 to 30% by mass with respect to the whole toner.

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto. The volume-based median diameter of the resin fine particles and the volume-based median diameter of the colorant fine particles were performed as described above.
The glass transition point (Tg) of the resin fine particles and the toner was measured using “Diamond DSC” (manufactured by Perkin Elmer).

[Preparation Example of Resin Fine Particle Dispersion MD1: Resin Fine Particles Encapsulating Release Agent]
(First stage polymerization)
A 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device was charged with a solution prepared by dissolving 8 g of sodium dodecyl sulfate in 3 L of ion-exchanged water and stirred at a stirring speed of 230 rpm under a nitrogen stream. After raising the internal temperature to 80 ° C., a solution in which 10 g of potassium persulfate was dissolved in 200 g of ion-exchanged water was added, and the liquid temperature was again adjusted to 80 ° C.
Styrene 480g
n-Butyl acrylate 250g
Methacrylic acid 68g
After the monomer mixed liquid consisting of 1 was added dropwise over 1 hour, the mixture was heated and stirred at 80 ° C. for 2 hours for polymerization to prepare a resin fine particle dispersion [A1] in which resin fine particles [a1] were dispersed. .
(Second stage polymerization)
A 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device was charged with a solution of 7 g of polyoxyethylene (2) sodium dodecyl ether sulfate in 800 ml of ion-exchanged water and heated to 98 ° C. 260 g of the above resin fine particles [a1],
Styrene 245g
120g of n-butyl acrylate
n-octyl-3-mercaptopropionate 1.5 g
Mold release agent: behenate behenate (melting point 73 ° C.) 190 g
Is added to the monomer solution dissolved and mixed at 90 ° C., and mixed and dispersed for 1 hour by a mechanical disperser “CREARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path, to give emulsified particles (oil droplets) A dispersion containing was prepared.
Next, an initiator solution in which 6 g of potassium persulfate is dissolved in 200 ml of ion-exchanged water is added to this dispersion, and the system is polymerized by heating and stirring at 82 ° C. for 1 hour to obtain resin fine particles [a2]. A resin fine particle dispersion [A2] in which is dispersed is prepared.
(3rd stage polymerization)
A solution prepared by dissolving 11 g of potassium persulfate in 400 ml of ion-exchanged water was added to the resin fine particle dispersion [A2].
Styrene 435g
n-Butyl acrylate 130g
Methacrylic acid 33g
n-octyl-3-mercaptopropionate 8 g
A monomer mixture consisting of was added dropwise over 1 hour. After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C., whereby dispersion of resin fine particles [M1] containing a vinyl monomer as a main component and containing a release agent A liquid [MD1] was prepared.
With respect to this dispersion [MD1], the volume-based median diameter of the resin fine particles [M1] was measured and found to be 220 nm. Moreover, when the molecular weight of resin which comprises the said resin fine particle [M1] was measured, the weight average molecular weight was 59,500.

[Preparation Example of Resin Fine Particle Dispersion MD2: Resin Fine Particles not including a Release Agent]
Preparation Example MD of Resin Fine Particle Dispersion A dispersion [MD2] of resin fine particles [M2] was prepared in the same manner except that the release agent (behenate behenate) was not used.
With respect to this dispersion [MD2], the volume-based median diameter of the resin fine particles [M2] was measured and found to be 190 nm. Moreover, when the molecular weight of resin which comprises the said resin fine particle [M2] was measured, the weight average molecular weight was 57,500.

[Example of preparation of resin fine particle dispersion for shell layer SHD1]
Preparation Example of Resin Fine Particle Dispersion In the first stage polymerization step of MD1, a monomer mixture comprising 548 g of styrene, 156 g of 2-ethylhexyl acrylate, 96 g of methacrylic acid, and 16.5 g of n-octyl mercaptan was used. In the same manner, a dispersion [SHD1] of resin fine particles [SH1] for shell layer was prepared.
With respect to this dispersion [SHD1], the glass transition point of the resin fine particles [SH1] for shell layer was measured and found to be 53.0 ° C.

[Synthesis Example C1 of Crystalline Polyester]
In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device, 300 parts by mass of polycarboxylic acid compound: sebacic acid (molecular weight 202.25) and polyhydric alcohol compound: 1,6-hexane The diol (molecular weight 118.17) was charged in an amount of 170 parts by mass, the internal temperature was raised to 190 ° C. over 1 hour while stirring this system, and after confirming that the system was uniformly stirred, Ti (OBu) ₄ was added in an amount of 0.003% by mass based on the charged amount of the polyvalent carboxylic acid compound. Thereafter, the internal temperature is raised from 190 ° C. to 240 ° C. over 6 hours while distilling off the generated water, and the dehydration condensation reaction is continued over 6 hours under the condition of a temperature of 240 ° C. for polymerization. As a result, crystalline polyester [C1] was obtained.
The resulting crystalline polyester [C1] had a melting point (Tm) of 83 ° C. and a number average molecular weight of 6,300.

[Preparation Example CD1 of Crystalline Polyester Fine Particle Dispersion]
30 parts by mass of crystalline polyester [C1] was melted and transferred to the emulsification disperser “Cavitron CD1010” (manufactured by Eurotech Co., Ltd.) at a transfer rate of 100 parts by mass per minute. Simultaneously with the transfer of the crystalline polyester [C1] in the molten state, 70 mass parts of reagent ammonia water was diluted with ion-exchanged water in an aqueous solvent tank with respect to the emulsifying disperser, and the concentration was 0.37 mass%. The diluted ammonia water was transferred at a transfer rate of 0.1 liters per minute while being heated to 100 ° C. with a heat exchanger. Then, by operating this emulsification disperser under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , a crystalline polyester [C1] having a volume-based median diameter of 200 nm and a solid content of 30 parts by mass. A dispersion of fine particles [CD1] was prepared.

[Preparation Example of Resin Fine Particle Dispersion SD1: Resin Fine Particles Encapsulating Crystalline Polyester]
Into a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device, 2000 parts by mass of a fine particle dispersion [CD1] of crystalline polyester [C1] and 1150 parts by mass of ion-exchanged water were charged. A polymerization initiator solution in which 10.3 parts by mass of potassium persulfate was dissolved in 210 parts by mass of ion-exchanged water was added, and under a temperature condition of 80 ° C.,
Styrene 380 parts by weight n-butyl acrylate 190 parts by weight Methacrylic acid 30 parts by weight n-octyl mercaptan 8.2 parts by weight of a polymerizable monomer mixture was added dropwise over 2 hours, followed by heating and stirring at 80 ° C. for 2 hours. Then, seed polymerization was performed, and after the polymerization was completed, a dispersion liquid [SD1] of resin fine particles [S1] containing crystalline polyester [C1] was prepared by cooling to 28 ° C.

[Preparation Example of Resin Fine Particle Dispersion SD2: Resin Fine Particles Encapsulating Crystalline Polyester]
In preparation example SD1 of the dispersion of resin fine particles, the polymerizable monomer mixture to be dropped is
Styrene 435 parts by weight n-butyl acrylate 130 parts by weight Methacrylic acid 33 parts by weight n-octyl-3-mercaptopropionate Resin enclosing crystalline polyester [C1] in the same manner except that it consists of 8 parts by weight A dispersion [SD2] of fine particles [S2] was prepared.

[Preparation Example Bk of Colorant Fine Particle Dispersion]
90 parts by mass of sodium polyoxyethylene-2-dodecyl ether sulfate was stirred and dissolved in 1510 parts by mass of ion-exchanged water. While stirring this solution, 400 parts by mass of carbon black “Regal 330” (manufactured by Cabot) is gradually added, and then dispersed using a stirrer “Claremix” (manufactured by M Technique). Thus, a dispersion of colorant fine particles [Bk] was prepared.
The volume-based median diameter of the colorant fine particles in the dispersion liquid [Bk] of the colorant fine particles was measured and found to be 110 nm.

[Preparation Example WD1 of Release Agent Fine Particle Dispersion]
Tribehenate citrate wax (melting point: 83.2 ° C.) 60 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku Co., Ltd.) 5 parts by mass Ion-exchanged water And then sufficiently dispersed with "Ultra Turrax T50" (manufactured by IKA), and then dispersed with a pressure discharge type gorin homogenizer, and a release agent fine particle dispersion having a volume average diameter of 240 nm and a solid content of 20% by mass. [WD1] was prepared.

[Toner Production Example 1: Example 1]
In a zebra flask equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device, 2500 parts by mass of ion-exchanged water, 600 parts by mass of the dispersion [MD1] (in terms of solid content), 300 parts by mass of the dispersion [SD1] (solid) And a dispersion of colorant fine particles [Bk] (500 parts by mass) and the liquid temperature was adjusted to 25 ° C., and then the pH was adjusted to 10 by adding an aqueous solution of sodium hydroxide having a concentration of 25% by mass. .
Next, an aqueous solution in which 54.3 parts by mass of magnesium chloride hexahydrate is dissolved in 54.3 parts by mass of ion-exchanged water is added, and then the temperature of the system is raised to 97 ° C. to thereby form each resin fine particle. And agglomeration reaction of the colorant fine particles was started.
After the start of this agglomeration reaction, sampling is performed periodically, and the volume-based median diameter of the particles is measured using a particle size distribution analyzer “Coulter Multisizer 3” (manufactured by Beckman Coulter). Aggregation was continued while stirring was continued until 6.3 μm.
Thereafter, an aqueous solution in which 23.0 parts by mass of sodium chloride was dissolved in 92 parts by mass of ion-exchanged water was added, the temperature of the system was kept at 95 ° C., and stirring was continued for 4 hours. When the circularity reached 0.946 as measured by (Sysmex), the reaction was stopped by cooling to 30 ° C. under conditions of 6 ° C./min to obtain a dispersion of toner particles. The toner particles after cooling had a particle size of 6.1 μm and a circularity of 0.946.
The toner particle dispersion thus obtained was subjected to solid-liquid separation using a basket-type centrifuge “MARK III Model No. 60 × 40” (manufactured by Matsumoto Kikai Co., Ltd.) to form a wet cake. This wet cake was repeatedly washed and solid-liquid separated with the basket-type centrifuge until the electric conductivity of the filtrate reached 15 μS / cm. Thereafter, a “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.) was used, and the temperature was 40 The toner particles [1X] were obtained by spraying a stream of air at 20 ° C. and a humidity of 20% RH until the water content became 0.5% by mass and cooling to 24 ° C.

To the obtained toner particles [1X], 1% by mass of hydrophobic silica particles and 1.2% by mass of hydrophobic titanium oxide particles are added, and the condition of the peripheral speed of the rotor blades is 24 m / s using a Henschel mixer. Was added for 20 minutes, and an external additive was added by passing through a 400 mesh sieve to obtain toner [1].
It was 37 degreeC when the glass transition point was measured about the obtained toner [1].
In toner [1], the shape and particle size of the toner particles did not change with the addition of hydrophobic silica particles and hydrophobic titanium oxide particles.

[Toner Production Example 2: Example 2]
In the toner production example 1, the timing of the addition of the dispersion [SD1] is the same as that after the addition of the magnesium chloride aqueous solution and before the start of the temperature increase. 2] was obtained.

[Toner Production Example 3: Example 3]
In a zebra flask equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, 2500 parts by mass of ion-exchanged water, 540 parts by mass of the dispersion [MD1] (in terms of solid content), 300 parts by mass of the dispersion [SD1] (solid) And a dispersion of colorant fine particles [Bk] (500 parts by mass) and the liquid temperature was adjusted to 25 ° C., and then the pH was adjusted to 10 by adding an aqueous solution of sodium hydroxide having a concentration of 25% by mass. .
Next, an aqueous solution in which 54.3 parts by mass of magnesium chloride hexahydrate is dissolved in 54.3 parts by mass of ion-exchanged water is added, and then the temperature of the system is raised to 97 ° C. Aggregation reaction with the colorant fine particles was started.
After the start of this agglomeration reaction, sampling is performed periodically, and the volume-based median diameter of the particles is measured using a particle size distribution analyzer “Coulter Multisizer 3” (manufactured by Beckman Coulter). Aggregation was continued while stirring was continued until 6.3 μm.
Thereafter, an aqueous solution in which 6.0 parts by mass of sodium chloride was dissolved in 24 parts by mass of ion-exchanged water was added, and the temperature of the system was 95 ° C., and stirring was continued for 1 hour.
Next, 60 parts by mass of the dispersion [SHD1] (in terms of solid content) was added and stirring was continued at 92 ° C. for 2 hours to fuse the shell layer resin fine particles [SH1] to the surface of the core particles. A layer was formed. Thereafter, an aqueous solution in which 17 parts by mass of sodium chloride is dissolved in 68 parts by mass of ion-exchanged water is added to perform aging treatment, and the circularity is 0 as measured by a flow type particle image analyzer “FPIA-2100” (manufactured by Sysmex). When the temperature reached 945, the reaction was stopped by cooling to 30 ° C. under the condition of 6 ° C./min to obtain a dispersion of toner particles. The toner particles after cooling had a particle size of 6.1 μm and a circularity of 0.945.
The toner particle dispersion thus obtained was washed and dried in the same manner as in Toner Production Example 1, and an external additive was added to obtain a toner [3].

[Toner Production Example 4: Example 4]
Toner [4] was obtained in the same manner as in Toner Production Example 1 except that dispersion [SD2] was added instead of dispersion [SD1].

[Toner Production Example 5: Comparative Example 1]
In toner production example 1, instead of the dispersion [MD1], 500 parts by mass of the dispersion [MD2] (in terms of solid content) is used, and 100 parts by mass of the above releasing agent fine particle dispersion [WD1] (in terms of solids) A comparative toner [5] was obtained in the same manner except that it was used.

[Toner Production Example 6: Comparative Example 2]
In Toner Production Example 1, the amount of the dispersion [MD1] used was changed to 750 parts by mass (in terms of solid content), and a dispersion of fine particles of crystalline polyester [C1] [CD1] instead of the dispersion [SD1] A comparative toner [6] was obtained in the same manner except that 150 parts by mass (in terms of solid content) was used.

[Developer Production Examples 1 to 6]
To each of the toners [1] to [6], a ferrite carrier having a volume-based median diameter of 60 μm coated with a silicone resin is added so that the toner concentration becomes 6% by mass, and mixed by a V-type mixer. As a result, developers [1] to [6] were produced.

(1) Evaluation of low-temperature fixability Among the minimum fixing temperature by the following rub fixing test and the minimum fixing temperature by the low-temperature offset test, the higher temperature was evaluated as the minimum fixing temperature. In this invention, the case where it is 140 degrees C or less is set as a pass. The results are shown in Table 1.

(1-1) Minimum Fixing Temperature by Rubbing Fixing Test A commercially available multifunction machine “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies) is used as an image forming apparatus, and developers [1] to [6] are used as developers. The target temperature of the surface temperature of the fixing heating member in the heat roller fixing type fixing means is changed in increments of 5 ° C. in the range of 80 to 180 ° C., and the surface temperature is monitored for each temperature while monitoring the surface temperature. In a humid environment (temperature 20 ° C., humidity 50% RH), image formation was performed using A4 size fine paper weighing 80 g as an image recording sheet to obtain a test print. The test print patch image measurement area was rubbed 14 times with a load of 22 g / cm ² using plain weave exposed cotton, the image density of the measurement area was measured, and the rubbing fixing rate was calculated according to the following formula 1. Then, the temperature at which the rubbing fixing rate becomes 90% was calculated by linear interpolation, and was set as the minimum fixing temperature by the rubbing fixing test.
Formula 1: Rub fixing rate (%) = (Image density after rubbing / Image density before rubbing) × 100
The image density of the patch image was measured with a Macbeth reflection densitometer “RD-918”. The image density was a relative density with respect to white paper, and a patch image having a density of 1.00 ± 0.05 was selected as the measurement unit.

(1-2) Minimum Fixing Temperature by Low-Temperature Offset Test A commercially available multifunction device “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies) is used as an image forming apparatus, and developers [1] to [6] are used as developers. The target temperature of the surface temperature of the fixing heating member in the heat roller fixing type fixing means is changed in increments of 5 ° C. in the range of 80 to 180 ° C., and the surface temperature is monitored for each temperature while monitoring the surface temperature. An A4 image having a solid black belt-like image with a width of 5 mm in the direction perpendicular to the conveying direction using a high-quality paper of A4 size weighing 80 g as an image recording sheet in a humid (temperature 20 ° C., humidity 50% RH) environment. After having been conveyed and fixed by vertical feeding, a solid black belt image having a width of 5 mm and a halftone image having a width of 20 mm are perpendicular to the conveying direction. 4 conveys the image at lateral feed, image contamination caused by fixing the offset A temperature was measured when they occur. The lowest temperature at which the fixing offset could not be visually confirmed was defined as the lowest fixing temperature by the low temperature offset test.

(2) Hot offset resistance A commercially available multifunction machine “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc.) is used as an image forming apparatus, and developers [1] to [6] are mounted as developers, respectively. In a high humidity (temperature 30 ° C., humidity 80% RH) environment, the fixing roller temperature is changed in increments of 5 ° C. within a range of 100 ° C. to 210 ° C., and each temperature has a width of 5 cm in the direction perpendicular to the conveying direction. An A4 image having a solid band image is conveyed and fixed by vertical feeding, the image after fixing is visually confirmed, and the lowest temperature at which roughness of the image surface or minute uneven gloss is observed is defined as a hot offset temperature. Thus, the hot offset resistance was evaluated. In this invention, the case where hot offset temperature is 200 degreeC or more is set as a pass. The results are shown in Table 1.

(3) Halftone unevenness As the image forming apparatus, a commercially available multifunction machine “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies) is used, and developers [1] to [6] are mounted as developers, respectively. A halftone image was output in a humid environment (temperature 20 ° C., humidity 50% RH). The image density at 10 locations of this halftone image is measured using “Macbeth RD918” (manufactured by Macbeth), and the maximum image density difference (ΔHD = maximum density−minimum density) is calculated. The unevenness was evaluated. In the present invention, it is particularly preferable that the image density difference is less than 0.1, and the image density difference is 0.05 or less. The results are shown in Table 1.

(4) Charge amount 19 g of carrier and 1 g of toner are put in a 20 ml glass container, 200 times per minute, swing angle 45 degrees, arm 50 cm for 20 minutes, normal temperature and normal humidity (temperature 20 ° C., humidity 50% RH). After shaking below, the charge amount was measured by the blow-off method shown below.
Blow off charge measurement device “TB-200” (manufactured by Toshiba Chemical Co., Ltd.) equipped with a 400 mesh stainless steel screen was blown with nitrogen gas for 10 seconds under the condition of a blow pressure of 0.5 kgf / cm ² and measured. The charge amount (μC / g) was calculated by dividing the charge amount by the mass of the flying toner.
If the charge amount is 30 μC / g or more, there is no practical problem and it is determined that the present invention is acceptable. The results are shown in Table 1.

(5) Image Density As an image forming apparatus, a commercially available multifunction machine “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc.) is used, and developers [1] to [6] are mounted as developers, respectively. A solid image was output in an environment (temperature 20 ° C., humidity 50% RH). The relative reflection density with respect to white paper was measured using “Macbeth RD918” (manufactured by Macbeth Co., Ltd.), and the average value was calculated, and the image density was evaluated accordingly. In the present invention, a case where the image density is 1.30 or more is determined to be acceptable. The results are shown in Table 1.

(6) Heat-resistant storage stability After taking 0.5 g of toner in a 10-ml glass bottle with an inner diameter of 21 mm, closing the lid, and using a shaker “Tap Denser KYT-2000” (manufactured by Seishin Enterprise Co., Ltd.), after shaking 600 times at room temperature. The sample was left for 2 hours in an environment of a temperature of 55 ° C. and a humidity of 35% RH with the lid opened. Next, the toner is placed on a 48 mesh (aperture 350 μm) sieve, taking care not to break up the toner aggregates, and set in a “powder tester” (manufactured by Hosokawa Micron). After fixing and adjusting the vibration intensity to a feed width of 1 mm, applying vibration for 10 seconds, the ratio (mass%) of the amount of toner remaining on the sieve was measured, and the toner aggregation rate was calculated by the following formula 2. The heat resistant storage stability was evaluated based on the obtained toner aggregation rate.
In the present invention, when the toner aggregation rate is less than 15%, the heat-resistant storage property is evaluated as extremely good, and when the toner aggregation rate is 15% or more and 20% or less, the heat-resistant storage property is determined. When the toner aggregation rate exceeds 20%, the heat resistant storage stability is poor and there is a problem in practical use. In this evaluation, the acceptable level is when the toner aggregation rate is 20% or less. The results are shown in Table 1.
Formula 2: Toner aggregation rate (%) = (residual toner mass (g) on sieve) /0.5 (g) × 100

Claims (4)

A method for producing an electrostatic image developing toner comprising toner particles containing a binder resin containing a crystalline polyester and an amorphous vinyl polymer, a colorant, and a release agent,
A method for producing a toner for developing an electrostatic image, comprising at least the following steps (a) to (c):
(A) Step of producing resin fine particles (M) made of vinyl polymer A containing a release agent (b) A vinyl monomer is added to an aqueous medium in which crystalline polyester fine particles are dispersed, Step of producing resin fine particles (S) in which the crystalline polyester fine particles are coated with the vinyl polymer B by performing seed polymerization with the vinyl monomer using the crystalline polyester fine particles as seed particles (c) A step of agglomerating and fusing the resin fine particles (M), the resin fine particles (S), and the colorant fine particles in an aqueous medium.   2. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the resin fine particles (M) are formed by forming an outermost layer composed only of the vinyl polymer A. 3.   In the step (c), after adding the flocculant to the aqueous medium in which the resin fine particles (M) and the colorant fine particles are dispersed, the resin fine particles (S) are added to the aqueous medium. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the toner is an electrostatic charge image developing toner. The shelling step of forming a shell layer by agglomerating and fusing fine particles of an amorphous resin on the surface of the associated particles obtained by performing the step (c) is performed. A method for producing a toner for developing an electrostatic charge image according to claim 3.