JP2012118468A - Toner for electrostatic latent image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner that can be fixed at a temperature lower than a conventional toner and has excellent heat-resistant storage property.SOLUTION: The toner is a core-shell toner comprising a core particle containing a first resin and a colorant and a shell layer containing a second resin, and is obtained by an emulsion aggregation method. The first resin and the second resin are compatible. A mass ratio of the second resin to the first resin in the core-shell toner is 3 mass% or more and 20 mass% or less. The loss tangent (tan δ) of the dynamic viscoelasticity of the core-shell toner shows two of maxima or shoulders in a range from 40°C or higher and lower than 100°C.

Description

  The present invention relates to a toner for developing an electrostatic charge image used in electrophotography, electrostatic recording method and the like.

  As a toner structure that achieves both low-temperature fixability and heat-resistant storage stability, a so-called core-shell structure in which a resin having a low glass transition point is coated with a resin having a high glass transition point has been proposed. In Patent Document 1, after the binder resin dispersion used for the core and the colorant dispersion are mixed (if necessary, the release agent dispersion is also mixed), heating, pH control, aggregating agent After agglomerating until a desired particle size is formed by addition or the like to form core agglomerated particles, a shell layer that covers the core agglomerated particles is formed by newly adding a dispersion of shell fine particles, and the obtained core shell A core-shell toner is produced by fusing the agglomerated particles to a temperature equal to or higher than the glass transition temperature of the binder resin. In the above method, when the core resin and the shell resin are highly compatible, there is an advantage that the shell fine particles are firmly bonded to the core particle, but if the heat treatment is performed at a Tg or more of each other, the core resin and the shell resin Is partially compatible. As a result, the Tg of the shell resin decreases due to the influence of the core resin, or the core particles are exposed due to the core particles being easily oozed out. Storage properties may not be demonstrated.

  With respect to such a problem, Patent Document 2 focuses on the dynamic viscoelasticity of the core-shell toner, considers the solubility parameter of the core resin and the shell resin, and makes the core resin and the shell resin phase separated. Thus, a method for effectively expressing the characteristics of the core resin and the shell resin has been proposed. However, in the case of such a method, since the core resin and the shell resin have a low affinity, when the sufficient amount of heat is applied in the fusion process, the core resin and the shell resin form respective domains. When the addition amount of the shell resin is small, the core particles are exposed and the blocking resistance may not be sufficient. Further, since the compatibility between the core resin and the shell resin is low, the adhesion between the core particles and the shell particles is not sufficient, and the shell fine particles are detached due to a fusion process, a washing process at the time of toner production, stress in the developing machine, and the like. In some cases, such as separation, blocking resistance and durability may not be sufficient.

  Further, in the case of the core-shell toner obtained by the production method described in Patent Document 1 or Patent Document 2, the core aggregated particles are aggregates of fine particles, so that the core aggregated particles are bulky and have a large surface area. Therefore, as compared with spherical core particles, a large amount of shell fine particles is inevitably required to sufficiently cover the core particles. For example, when the 0.10 μm shell fine particles are attached to the core aggregate particles having an average particle size of 5.5 μm, the core particles are assumed to be true spheres and are attached in an amount necessary for further coating with the shell fine particles. However, the heat storage stability was not sufficiently improved. In order to improve the heat-resistant storage property, it is conceivable to increase the shell fine particle content. However, in this case, the low-temperature fixability is deteriorated, so that it is difficult to achieve both the low-temperature fixability and the blocking resistance.

JP 2006-235027 A JP 2006-293285 A

  An object of the present invention is to solve the above-described problems, and to provide a toner that can be fixed at a lower temperature than the conventional one and that is excellent in heat-resistant storage stability.

  The present invention is a core-shell toner obtained by an emulsion aggregation method, having core particles containing a first resin and a colorant, and a shell layer containing a second resin, The second resin is compatible, and the mass ratio of the second resin to the first resin in the core-shell toner is 3% by mass or more and 20% by mass or less; The present invention relates to a core-shell toner characterized in that the tangent loss (tan δ) of viscoelasticity has either a maximum value or a shoulder in the range of 40 ° C. or more and less than 100 ° C.

  According to the present invention, it is possible to provide a core-shell toner that can be fixed at a lower temperature than before and that is excellent in heat-resistant storage stability.

  The toner of the present invention is a core-shell toner obtained by a so-called emulsion aggregation method having core particles containing a first resin and a colorant and a shell layer containing a second resin. Furthermore, the first resin and the second resin used in the toner of the present invention have compatibility between them. Here, the compatibility of the first resin and the second resin is such that the first resin and the second resin are heated at a temperature equal to or higher than the softening temperature (Tm) of each other, such as a heating roll, a kneader, and an extruder. This can be confirmed by measuring the dynamic viscoelasticity of a resin obtained by sufficiently melting and kneading using a heat kneader. Moreover, if SP value (solubility parameter) of 1st resin and 2nd resin is near, it can be said that both are highly compatible. Specifically, the difference in SP value between the first resin and the second resin is preferably less than 1.0, and the difference in SP value is more preferably less than 0.5. Here, the SP value is a value calculated by the Fedors method.

  In the core-shell toner of the present invention, the mass ratio of the second resin to the first resin is 3% by mass or more and 20% by mass or less. When the mass ratio is less than 3% by mass, the amount of the second resin constituting the shell layer is too small, so that the core particles are easily exposed on the toner surface, and the heat resistant storage property of the toner is deteriorated. On the other hand, when the mass ratio is larger than 20 mass%, the toner fixing property is deteriorated. The mass ratio of the second resin to the first resin is preferably 5% by mass or more and 20% by mass or less, and more preferably 10% by mass or more and 18% by mass or less. The mass ratio can be calculated from the usage amounts of the first resin and the second resin when the core-shell toner is manufactured.

  The core-shell toner in the present invention has two maximum values or shoulders in the range where the tangent loss (tan δ) of dynamic viscoelasticity is 40 ° C. or higher and lower than 100 ° C. This indicates that the first resin contained in the core particles and the second resin contained in the shell layer have individual glass transition points. That is, it means that the first resin contained in the core particles and the second resin contained in the shell layer exist in an incompatible state in the toner without being mutually compatible.

  In the present invention, the maximum value or shoulder of the tangent loss (tan δ) is derived from the glass transition point of the first resin and the second resin. When the glass transition points of the first resin and the second resin are relatively close, they are detected as shoulders, and when they are separated from each other, they are detected as maximum values. In general, in the core-shell toner, the resin used for the core particles has a low glass transition point for obtaining low-temperature fixability, and the resin used for the shell layer has a high glass transition point for obtaining durability. In this case, there exists a maximum value or shoulder on the low temperature side at the temperature at which the resin used for the core particles transitions from a glass state to a thermally deformable state. Moreover, there exists a maximum value or shoulder on the high temperature side at the temperature at which the resin used for the shell layer transitions from a glass state to a thermally deformable state.

  In the present invention, in order to sufficiently exhibit low-temperature fixability, it is preferable that the maximum value or shoulder of the tangent loss (tan δ) derived from the first resin is in the range of 40 ° C. or higher and lower than 70 ° C. When the maximum value of the tangent loss (tan δ) derived from the first resin or the position of the shoulder is lower than 40 ° C., the heat resistant storage property of the toner is deteriorated. Further, when the maximum value of the tangent loss (tan δ) derived from the first resin or the position of the shoulder is higher than 70 ° C., the low temperature fixability may not be obtained. Moreover, it is preferable that the maximum value or shoulder of the tangent loss (tan δ) derived from the second resin is in the range of 70 ° C. or more and less than 100 ° C. When the maximum value of the tangent loss (tan δ) derived from the second resin or the shoulder position is lower than 70 ° C., the heat-resistant storage property of the toner is deteriorated. If the maximum value of the tangent loss (tan δ) derived from the second resin or the shoulder position is higher than 100 ° C., the low-temperature fixability may not be obtained.

  As described above, in the core-shell toner of the present invention, the first resin and the second resin are compatible, and the first resin and the second resin are sufficiently phase-separated in the core-shell toner. It is the composition which is. With such a structure, the core-shell toner of the present invention is such that the core particles and the shell particles are firmly bonded to each other, and the performance of the designed core resin and shell resin is functionally separated while the amount of added shell fine particles is small. It is estimated that it is in a state where it can be exerted. As a result, it is considered that further low-temperature fixing properties and heat-resistant storage properties can be achieved at a high level.

  As a production method for obtaining the core-shell toner of the present invention, an emulsion aggregation method having the steps described below is preferably used. That is, a core in which an aqueous dispersion of resin fine particles having a first resin and an aqueous dispersion of a colorant are mixed and the first resin fine particles and the colorant are aggregated in an aqueous medium to form core aggregated particles. The aggregation step, the primary fusion step in which the core aggregated particles are heated to the glass transition point Tg1 or higher of the first resin and fused to obtain the core particles, and the temperature of the aqueous medium containing the core particles is lower than Tg1 A cooling step of cooling to a temperature, and an aqueous dispersion of the second resin fine particles having the second resin and a flocculant are mixed at a temperature lower than Tg1, and the second resin fine particles are adhered to the core particles to adhere to the shell It is preferable to have a shell adhesion step for obtaining a body and a secondary fusion step for heating the shell adhesion body at Tg1 or more and at or below the glass transition point Tg2 of the second resin.

<Core aggregation process>
The core agglomeration step is prepared by mixing an aqueous dispersion of resin fine particles having a first resin, an aqueous dispersion of fine colorant particles and, if necessary, a toner component such as a release agent to prepare a mixed solution. In this step, the particles contained in the mixed liquid are aggregated to form core aggregated particles. As a method for forming core agglomerated particles, a method in which an aggregating agent is added and mixed in the above mixed solution, and heated or mechanical power or the like is appropriately added can be preferably exemplified.

  The average particle size of the formed core aggregated particles is not particularly limited, but the shell adhering particles after the shell adhering step described later should be approximately the same as the average particle size of the toner to be finally obtained. It is good to control. The particle size control of the core agglomerated particles can be performed, for example, by appropriately setting and changing the temperature, the solid content concentration, the aggregating agent concentration, the stirring conditions, and the like.

<Primary fusion process>
The primary fusion step is a step of obtaining core particles in which the surface of the core aggregated particles is smoothed by heating and coalescing the core aggregated particles to a glass transition point (Tg1) or higher of the first resin. Since the surface area of the core aggregated particles is greatly reduced by this step, even if the amount of shell fine particles covering the core particles is small compared to the conventional case, the core particles are assumed to be true spherical and further coated with shell fine particles. If it is attached in an amount necessary for the heat resistance, the heat-resistant storage property is improved. Before entering the primary fusing step, a chelating agent, a pH adjusting agent, a surfactant and the like can be appropriately added in order to prevent fusion between toner particles. Among them, the chelating agent is preferably used because it is difficult for the colorant and the release agent to be detached and has an effect of suppressing metal crosslinking in the toner.

  Examples of chelating agents include alkali metal salts such as ethylenediaminetetraacetic acid (EDTA) and its Na salt, sodium gluconate, sodium tartrate, potassium citrate, sodium citrate, nitrotriacetate (NTA) salts, both COOH and OH There are many water-soluble polymers (polyelectrolytes) that contain the following functionalities.

  The heating temperature may be between the glass transition temperature (Tg1) of the first resin contained in the core aggregated particles and the temperature at which the resin is thermally decomposed. As the heating / fusion time, a short time is sufficient if the heating temperature is high, and a long time is required if the heating temperature is low. That is, the heating / fusion time depends on the temperature of heating and cannot be defined unconditionally, but is generally 10 minutes to 10 hours.

<Cooling process>
The cooling step is a step of cooling the temperature of the aqueous medium containing the core particles to a temperature lower than the glass transition point (Tg1) of the first resin. If the cooling is not performed to a temperature lower than Tg1, coarse particles are generated when a flocculant is added in the shell adhesion step described later.

<Shell adhesion process>
The shell adhering step refers to mixing an aqueous dispersion of second resin fine particles having a second resin and a flocculant at a temperature lower than the glass transition point (Tg1) of the first resin, This is a step of attaching a resin fine particle to obtain a shell adhering body. It is preferable that the shell attaching step is performed after the cooling step without isolating the core particles by filtration or the like. When the core particles are once isolated from the aqueous medium containing the core particles by filtration or the like and then a shell deposit is obtained, the surfactant necessary for redispersion in the aqueous medium and the surfactant are removed. This is not preferable because a large amount of washing water is required.

<Secondary fusion process>
In the secondary fusion step, the shell adhering body is heated and fused to the glass transition point (Tg2) of the first resin or higher and to the glass transition point (Tg2) of the second resin or less, so that This is a step of fixing the shell fine particles. By the secondary fusion process, the core resin and the shell resin are sufficiently bound, and the shell is prevented from being detached from the toner by operations such as washing and filtration described later. Before entering the secondary fusion step, a chelating agent, a pH adjuster, a surfactant, and the like can be appropriately added in order to prevent fusion between toner particles. Among them, the chelating agent is preferably used because it is difficult for the attached shell fine particles to be detached.

  The heating temperature is preferably between the glass transition point (Tg1) of the first resin contained in the shell adhering body and the glass transition point (Tg2) of the second resin. When the heating temperature is lower than the glass transition point (Tg1) of the first resin, the shell particles are detached in the cleaning step described later. In addition, when the heating temperature exceeds the glass transition point (Tg2) of the second resin, partial compatibilization occurs due to the high affinity between the first resin and the second resin. The low temperature fixability of the original first resin and the heat resistant storage property of the second resin cannot be exhibited. As the heating / fusion time, a short time is sufficient if the heating temperature is high, and a long time is required if the heating temperature is low. That is, the heating / fusion time depends on the temperature of heating and cannot be defined unconditionally, but is generally 10 minutes to 10 hours.

  The reaction liquid containing toner particles obtained after the end of the secondary fusion step is cooled to room temperature under appropriate conditions, and washed, filtered, dried, and the like to obtain toner particles. Further, a shearing force is applied to the surface of the obtained toner particles by applying inorganic particles such as silica, alumina, titania, calcium carbonate, and resin particles such as vinyl resin, polyester resin, and silicone resin in a dry state. It may be added. These inorganic particles and resin particles function as external additives such as fluidity aids and cleaning aids.

  The weight average particle diameter (D4) of the toner particles is preferably 4.5 to 7.0 μm, and more preferably 5.0 to 6.5 μm. If the weight average particle diameter (D4) of the toner particles is within the above range, the chargeability and developability of the toner will be good.

<Resin>
Examples of the first resin and the second resin that can be used in the present invention include the following. Homopolymers or copolymers of styrenes such as styrene, parachlorostyrene, α-methylstyrene (styrene resin); methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, acrylic acid Homopolymers or copolymers of esters having vinyl groups such as lauryl, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc. Resin); homopolymers or copolymers of vinyl nitriles such as acrylonitrile and methacrylonitrile (vinyl resins); vinyl ether homopolymers or copolymers such as vinyl ethyl ether and vinyl isobutyl ether (vinyl resins); Vinyl methyl ketone, vinyl ethyl keto , Homopolymers or copolymers of vinyl isopropenyl ketones (vinyl resins); homopolymers or copolymers of olefins such as ethylene, propylene, butadiene, isoprene (olefin resins); epoxy resins, polyester resins , Non-vinyl condensation resins such as polyurethane resins, polyamide resins, cellulose resins, and polyether resins, and graft polymers of these non-vinyl condensation resins and vinyl monomers. Of these, a polyester resin having sharp melt properties and excellent strength even at a low molecular weight is particularly preferable.

  The aqueous dispersions of the first resin and the second resin can be prepared by the following known methods (phase inversion emulsification method, forced emulsification method, emulsion polymerization method, self-emulsification method, etc.), but are limited to these methods. Is not to be done. For example, in the case of the phase inversion emulsification method, first, the first resin and the surfactant are dissolved in an amphiphilic organic solvent alone or in a mixed solvent. While stirring the mixed solution with a known stirrer, emulsifier, disperser, etc., by dropping the aqueous medium, the oil phase and the water phase are reversed at a certain point, and the oil phase becomes oil droplets. Thereafter, an aqueous dispersion in which the first resin or the second resin is dispersed is obtained through a solvent removal step under reduced pressure. Examples of known stirrers, emulsifiers, and dispersers include ultrasonic homogenizers, jet mills, pressure homogenizers, colloid mills, ball mills, and sand mills, and these may be used alone or in combination.

  When the first resin has an acidic polar group, it is better to add a basic substance to the mixed solution of the resin and the surfactant, and then add the aqueous medium dropwise. It is preferable because a dispersion is obtained.

  The basic substance may be an inorganic or organic basic compound, and examples thereof include the following compounds. Inorganic bases such as ammonia, sodium hydroxide and potassium hydroxide; organic bases such as methylamine, dimethylamine, trimethylamine, ethylamine, dimethylaminoethanol and diethylaminoethanol. Among these, from the viewpoint of not causing hydrolysis, amines such as dimethylamine, triethylamine, and dimethylaminoethanol which are weak bases are preferable. The addition amount of the basic substance is preferably adjusted as appropriate so that the pH at the time of dispersion mixing becomes near neutral.

  The amphiphilic organic solvent means a solvent having a solubility in water at 20 ° C. of at least 5 g / L or more, preferably 10 g / L or more. When the solubility is less than 5 g / L, there is a problem that the particle diameter becomes coarse or the storage stability of the obtained aqueous dispersion is poor. Examples of the above-mentioned amphiphilic organic solvent include the following compounds. Alcohols such as ethanol, n-propanol, isopropanol, n-butanol and isobutanol; ketones such as methyl ethyl ketone, methyl isobutyl ketone and ethyl butyl ketone; ethers such as tetrahydrofuran and dioxane; ethyl acetate, acetic acid-n-propyl, Esters such as isopropyl acetate; glycol derivatives such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; 3-methoxy-3-methylbutanol, 3-methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol , Ethyl acetoacetate and the like. These solvents can be used singly or in combination of two or more.

  In the case where the first resin and the second resin are the vinyl compounds, known polymerization methods such as emulsion polymerization, miniemulsion polymerization, and seed polymerization are suitably used for the vinyl monomers. Then, a dispersion liquid in which the resin is dispersed in the aqueous medium is prepared.

  Since the particle size of the first resin dispersed in the aqueous medium is generally about 3 to 8 μm, the toner particle size is manufactured through a core aggregation step, a primary fusion step, a shell adhesion step, and a secondary fusion step described later. In order to maintain the composition uniformity of the toner used, the 90% cumulative particle size value (D90) is preferably 1 μm or less, and more preferably the 50% cumulative particle size value (D50) is 0.5 μm or less.

  In addition, the volume-based median diameter of the resin fine particles of the second resin forming the shell layer is preferably 0.05 to 0.3 μm, and more preferably 0.08 to 0.2 μm. If the median diameter of the resin fine particles of the second resin is within the above range, the fine particles hardly aggregate and easily adhere to the toner particles, so that the core particles can be coated in a nearly uniform state. . Furthermore, since the thickness of the shell layer is suitable, the fixability is also good. The dispersed particle diameters of the first resin and the second resin can be measured with a laser diffraction / scattering particle size distribution analyzer (LA-920: manufactured by Horiba, Ltd.).

  The glass transition point (Tg1) of the first resin is preferably 30 ° C. or higher and 60 ° C. or lower, and more preferably 40 ° C. or higher and 60 ° C. or lower. If Tg1 is within the above range, the strength of the toner particles and the aggregation of the toner particles can be prevented, and deterioration of transferability and occurrence of toner conveyance unevenness can be suppressed during a multi-endurance test. In addition, deterioration of image gloss when fixing at low temperature can be suppressed. The glass transition point (Tg2) of the second resin is preferably 60 ° C. or higher and 80 ° C. or lower, and more preferably 65 ° C. or higher and 80 ° C. or lower. When Tg2 is within the above range, the heat-resistant storage property and fixing property of the toner are improved. In addition, the said glass transition temperature (Tg) is a physical-property value measured based on JISK7121, and means the midpoint glass transition temperature described in this specification.

  The relationship between the glass transition point (Tg1) of the first resin and the glass transition point (Tg2) of the second resin is preferably Tg1 <Tg2. Further, if Tg1 and Tg2 are too close, the shell is mixed with the core at the time of fusion, and the core easily moves to the particle surface. Therefore, Tg1 + 5 (° C.) <Tg2 is more preferable.

<Colorant>
The aqueous dispersion of the colorant can be prepared by mixing the colorant, the aqueous medium and the dispersant with a known stirrer, emulsifier, disperser or the like. As the dispersant used here, for example, a known one such as a surfactant or a polymer dispersant may be used, or a newly synthesized one may be used. Any of the dispersants can be removed in the step of washing the toner, but from the viewpoint of washing efficiency, the surfactant described later is preferable, and among the surfactants, anionic surfactants, nonionic surfactants, etc. Is preferred. The amount of the dispersing agent to be mixed is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the colorant, and more preferably 2 to 10 parts by mass from the viewpoint of achieving both dispersion stability and toner cleaning efficiency. The colorant content in the colorant aqueous dispersion is not particularly limited, but is preferably about 1 to 30% by mass of the total mass of the colorant aqueous dispersion. The colorant dispersed in the aqueous medium preferably has a 90% cumulative particle diameter (D90) of 2 μm or less, more preferably 50 from the viewpoint of pigment dispersibility of the finally obtained toner. % Cumulative particle size value (D50) is 0.5 μm or less. The dispersed particle size of the colorant can be measured with a laser diffraction / scattering particle size distribution measuring device (LA-920: manufactured by Horiba, Ltd.).

  Known stirrers, emulsifiers and dispersers used when dispersing the colorant include ultrasonic homogenizers, jet mills, pressure homogenizers, colloid mills, ball mills, sand mills, paint shakers, and these can be used alone or in combination. Also good.

  As the surfactant, anionic surfactants such as sulfate ester, sulfonate, phosphate ester and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol type, Examples thereof include nonionic surfactants such as alkylphenol ethylene oxide adducts and polyhydric alcohols. Among these, nonionic surfactants and / or anionic surfactants are preferable. The nonionic surfactant may be used in combination with an anionic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together. The concentration of the surfactant in the aqueous medium is preferably about 0.5 to 5% by mass.

<Release agent>
In the present invention, a release agent can be used. The melting point of the release agent is preferably 150 ° C. or lower, more preferably 40 ° C. or higher and 130 ° C. or lower, and particularly preferably 40 ° C. or higher and 110 ° C. or lower. Examples of the release agent include the following. Low molecular weight polyolefins such as polyethylene; silicones having a melting point (softening point) upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide; ester waxes such as stearyl stearate; Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, ester wax, etc. Mineral and petroleum waxes; and their modified products. These release agents may be used alone, or two or more release agents may be mixed and used. The release agent is preferably used by adding 1 to 30 parts by mass with respect to 100 parts by mass of the binder resin.

  The release agent aqueous dispersion can be prepared by the following known methods, but is not limited to these methods. The aqueous dispersion of the release agent is prepared, for example, by adding a release agent to an aqueous medium containing a surfactant, heating it to a temperature higher than the melting point of the release agent, and having a strong shearing ability (for example, M It can be produced by dispersing in a particulate form with a “Clairemix W motion” manufactured by Technic Co., Ltd.) or a pressure discharge type disperser (for example, “Gorin homogenizer” manufactured by Gorin) and then cooling to below the melting point. . The average particle diameter D50 of the dispersed particle diameter of the release agent in the release agent dispersion is preferably 0.08 to 0.5 μm, and more preferably 0.1 to 0.3 μm. Moreover, it is preferable that the coarse particle of 0.6 micrometer or more does not exist. If the dispersed particle size is too small, the release of the release agent during fixing may be insufficient and the hot offset temperature may be lowered.If the dispersed particle size is too large, the release agent is exposed on the toner surface and the powder characteristics are deteriorated. It may worsen or cause photoconductor filming. If coarse particles are present, the toner composition may become non-uniform or a free release agent may be generated. The dispersed particle size can be measured with a laser diffraction / scattering particle size distribution analyzer (LA-920: manufactured by Horiba, Ltd.).

  In the release agent dispersion, it is preferable to add a surfactant at a ratio of 1% by mass to 20% by mass with respect to the release agent. If the ratio of the surfactant is too small, the release agent may not be sufficiently dispersed and storage stability may be inferior. If the proportion of the surfactant is too large, the chargeability of the toner, particularly the environmental stability, may be deteriorated.

  In the mixing step, the solid content concentration can be appropriately adjusted by adding water to the mixture of the aqueous dispersion as necessary. In the core aggregation step, in order to cause uniform aggregation, the solid content concentration is preferably 5 to 40% by mass, more preferably 5 to 30% by mass, and particularly preferably 5 to 20% by mass.

<Flocculant>
As the aggregating agent, a surfactant having an opposite polarity to the surfactant contained in the aqueous dispersion, an inorganic metal salt, a divalent or higher valent metal complex, and the like can be suitably used. These ionically neutralize the ionic surfactant in the aqueous dispersion of the fine resin particles having the acidic group of the first resin and the first resin, the aqueous dispersion of the colorant, and the aqueous dispersion of the release agent. The particles are aggregated by the effect of salting out and ionic crosslinking. Specifically, the following compounds are mentioned. Monovalent inorganic metal salts such as sodium chloride, sodium sulfate and potassium chloride; divalent inorganic metal salts such as calcium chloride, calcium nitrate, magnesium chloride, magnesium sulfate and zinc chloride; iron chloride (III), iron sulfate (III ), Trivalent metal salts such as aluminum sulfate and aluminum chloride; inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide and calcium polysulfide. Among these, a metal salt having a valence of 2 or more and a polymer thereof are preferably used because they are effective even when added in a small amount and have high cohesion. These may be used alone or in combination of two or more.

  The flocculant may be added in the form of a dry powder or an aqueous solution dissolved in an aqueous medium, but it is preferably added in the form of an aqueous solution in order to cause uniform aggregation. . Moreover, it is preferable to add and mix the said flocculant at the temperature below the glass transition temperature (Tg1) of 1st resin. When the mixing is performed under this temperature condition, aggregation proceeds uniformly. Said mixing can be performed using a well-known mixing apparatus, a homogenizer, a mixer, etc.

  Hereinafter, a method for measuring physical properties according to the present invention will be described.

<Dynamic viscoelasticity measurement>
In the present invention, the tangent loss (tan δ) is obtained from dynamic viscoelasticity measured by a sinusoidal vibration method. For measurement of this dynamic viscoelasticity, an ARES measuring device manufactured by Rheometric Scientific is used. The measurement of dynamic viscoelasticity is performed in the temperature range of 20 ° C. to 100 ° C. under the following conditions.
Measurement jig: A circular parallel plate having a diameter of 8 mm is used. A shallow cup corresponding to a circular parallel plate is used on the actuator side. The gap between the bottom of the shallow cup and the circular plate is about 2 mm.
Sample to be measured: The toner is used after being pressure-molded so as to be a disk-shaped sample having a diameter of about 8 mm and a height of about 2 mm.
Measurement frequency: 6.28 radians / second Measurement strain setting: The initial value is set to 0.1%, and then the measurement is performed in the automatic measurement mode.
-Sample extension correction: Adjust in automatic measurement mode. Measurement temperature: The temperature is raised from 20 ° C. to 100 ° C. at a rate of 1 ° C. per minute.

<Measurement of Molecular Weight Distribution, Weight Average Molecular Weight (Mw), Number Average Molecular Weight (Mn), etc. Measured by Gel Permeation Chromatography (GPC) of Resin Tetrahydrofuran (THF)>
The molecular weight distribution, the weight average molecular weight (Mw), the number average molecular weight (Mn), and the like measured by GPC of the THF soluble content of the resin fine particles are determined as follows.

The column is stabilized in a heat chamber at 40 ° C., and tetrahydrofuran (THF) as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 ml / min, and about 100 μl of THF sample solution is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, a standard polystyrene sample having a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh Corporation or Showa Denko is preferably used. is there. An RI (refractive index) detector is used as the detector. As a column, it is better to combine multiple commercially available polystyrene gel columns,
For example, shodex GPC KF-801, 802, 803, 804, 805, 806, 807, 800P manufactured by Showa Denko KK, TSKgel G1000H (HXL), G2000H (HXL), G3000H (HXL), G4000H (made by Tosoh Corporation HXL), G5000H (HXL), G6000H (HXL), G7000H (HXL), and a combination of TSK guard column.

  The sample is prepared as follows. Place the resin (sample) in tetrahydrofuran (THF), leave it for several hours, shake well, mix well with THF (until the sample is united), and let stand for more than 12 hours. At this time, the standing time in THF is set to be 24 hours or more. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5: manufactured by Tosoh Corporation, Excro Disc 25CR: manufactured by Gelman Science Japan Co., Ltd., etc. can be used) is passed. This is used as a GPC sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

<Measurement of acid value of resin>
The acid value of the resin is determined as follows. The basic operation conforms to JIS-K0070. The acid value refers to the number of mg of potassium hydroxide required to neutralize free fatty acids, resin acids and the like contained in 1 g of a sample.

(1) Reagent (a) Solvent: N / 10 potassium hydroxide ethyl alcohol solution using phenolphthalein as an indicator immediately before use of ethyl ether-ethyl alcohol mixture (1 + 1 or 2 + 1) or benzene-ethyl alcohol mixture (1 + 1 or 2 + 1) Neutralize with.
(B) Phenolphthalein solution: 1 g of phenolphthalein is dissolved in 100 ml of ethyl alcohol (95 v / v%).
(C) N / 10 potassium hydroxide-ethyl alcohol solution: Dissolve 7.0 g of potassium hydroxide in as little water as possible, add ethyl alcohol (95 v / v%) to 1 liter, leave it for 2 to 3 days, and filter. . The standardization is performed according to JIS K 8006 (basic matters regarding titration during the reagent content test).

(2) Operation Weigh 1-20 g of resin (sample) correctly, add 100 ml of solvent and a few drops of phenolphthalein solution as an indicator, and shake well until the sample is completely dissolved. In the case of a solid sample, dissolve it by heating on a water bath. After cooling, this is titrated with an N / 10 potassium hydroxide ethyl alcohol solution, and the end point of neutralization is defined as the time when the indicator is slightly red for 30 seconds. (3) Calculation formula The acid value is calculated by the following formula.
A = B × f × 5.661 / S
A: Acid value B: Amount used of N / 10 potassium hydroxide ethyl alcohol solution (ml)
f: Factor of N / 10 potassium hydroxide ethyl alcohol solution S: Sample (g)

<Particle size distribution analysis of resin fine particles and colorant fine particles>
For the analysis of the particle size distribution, a laser diffraction / scattering particle size distribution measuring device (Horiba, Ltd., LA-950) is used and measured according to the operation manual of the device. After dropping the surfactant aqueous solution into the circulating water, the release agent particle dispersion is dropped to the optimum concentration of the device, dispersed by ultrasonic for 30 seconds, the measurement is started, and the 50% cumulative particle size value (D50) and The 90% cumulative particle size value (D90) is determined.

<Particle size distribution analysis of toner particles>
The particle size distribution of the toner particles is measured by particle size distribution analysis by the Coulter method. A Coulter Counter TA-II or Coulter Multisizer II (manufactured by Coulter Inc.) is used as a measuring device, and measurement is performed according to the operation manual of the device. About 1% sodium chloride aqueous solution is prepared using 1st grade sodium chloride as electrolyte solution. As the electrolytic solution, for example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. As a specific measuring method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant in 100 to 150 ml of the electrolytic aqueous solution, and a measurement sample (toner particles) is added in 2 to 2 ml. Add 20 mg. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. The volume and number distribution of the toner particles are calculated by measuring the volume and the number of toner particles of 2.00 μm or more with the above measuring apparatus equipped with a 100 μm aperture as the aperture of the obtained dispersion treatment liquid. From the calculation result, the weight average particle diameter (D4) of the toner particles is obtained.

<Dynamic viscoelasticity measurement>
The measurement of dynamic viscoelasticity is performed in the temperature range of 20 ° C. to 100 ° C. under the following conditions.
Measurement jig: A circular parallel plate having a diameter of 8 mm is used. A shallow cup corresponding to a circular parallel plate is used on the actuator side. The gap between the bottom of the shallow cup and the circular plate is about 2 mm.
Sample to be measured: The toner is used after being pressure-molded so as to be a disk-shaped sample having a diameter of about 8 mm and a height of about 2 mm.
Measurement frequency: 6.28 radians / second Measurement strain setting: The initial value is set to 0.1%, and then the measurement is performed in the automatic measurement mode.
-Sample extension correction: Adjust in automatic measurement mode.
Measurement temperature: The temperature is raised from 20 ° C. to 100 ° C. at a rate of 2 ° C. per minute.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, the part number in an Example is a mass part, when there is no description in particular.

<Preparation of resin fine particle dispersion having first resin>
(Aqueous dispersion of polyester resin A)
Polyester resin A ((composition (molar ratio) / polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane: polyoxyethylene (2.0) -2,2-bis (4- Hydroxyphenyl) propane: terephthalic acid: fumaric acid: adipic acid: trimellitic acid = 30: 20: 18: 18: 10: 4), Mn; 5,200, Mw; 12,300, Tg; 45 ° C., acid value : 12 mg KOH / g) (1200 parts by mass) and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC-A) (0.5 parts by mass) were dissolved in THF (2400 parts by mass), and then dimethyl Aminoethanol (1 equivalent to the acid value of polyester resin A) was added and stirred for 10 minutes. Thereafter, ion-exchanged water (3600 parts by mass) was dropped using a homogenizer (manufactured by IKA: Ultra Tarrax T50) while stirring at a rotational speed of 5000 rpm. The obtained mixture was treated under reduced pressure (50 mmHg) at 50 ° C. to remove THF, and an aqueous dispersion of polyester resin A was obtained (solid content concentration: 25 wt%). When the particle size of the obtained aqueous dispersion was measured with a laser diffraction / scattering particle size distribution analyzer (LA-920: manufactured by Horiba, Ltd.), the 50% particle size based on the volume distribution of the resin fine particles was 0.12 μm. The 90% particle size was 0.15 μm.

(Aqueous dispersion of polyester resin B)
Polyester resin B ((composition (molar ratio) / polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane: polyoxyethylene (2.0) -2,2-bis (4- Hydroxyphenyl) propane: terephthalic acid: fumaric acid: adipic acid: trimellitic acid = 30: 20: 13: 13: 20: 4), Mn; 4,000, Mw; 10,300, Tg; 37 ° C., acid value : 14 mg KOH / g) (1200 parts by mass) and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC-A) (0.5 parts by mass) were dissolved in THF (2400 parts by mass), and then dimethyl Aminoethanol (1 equivalent with respect to the acid value of polyester resin B) was added and stirred for 10 minutes. Thereafter, ion-exchanged water (3600 parts by mass) was added dropwise with stirring at a rotational speed of 5000 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50). The obtained mixture was treated under reduced pressure (50 mmHg) at 50 ° C. to remove THF, and an aqueous dispersion of polyester resin B was obtained (solid content concentration: 25 wt%). When the particle size of the obtained aqueous dispersion was measured with a laser diffraction / scattering particle size distribution analyzer (LA-920: manufactured by Horiba, Ltd.), the 50% particle size based on the volume distribution of the resin fine particles was 0.00. The 90% particle diameter was 11 μm and 0.14 μm.

(Aqueous dispersion of polyester resin C)
Polyester resin C ((composition (molar ratio) / polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane: polyoxyethylene (2.0) -2,2-bis (4- Hydroxyphenyl) propane: terephthalic acid: fumaric acid: trimellitic acid = 25: 25: 26: 20: 4), Mn; 5,100, Mw; 11,300, Tg; 56 ° C., acid value: 15 mgKOH / g) (1200 parts by mass) and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC-A) (0.5 parts by mass) were dissolved in THF (2400 parts by mass), and then dimethylaminoethanol (polyester resin). 1 equivalent to the acid value of C) was added and stirred for 10 minutes. Thereafter, ion-exchanged water (3600 parts by mass) was dropped using a homogenizer (manufactured by IKA: Ultra Tarrax T50) while stirring at a rotational speed of 5000 rpm. The obtained mixture was treated under reduced pressure (50 mmHg) at 50 ° C. to remove THF, thereby obtaining an aqueous dispersion of polyester resin C (solid content concentration: 25 wt%). When the particle size of the obtained aqueous dispersion was measured with a laser diffraction / scattering particle size distribution analyzer (LA-920: manufactured by Horiba Seisakusho Co., Ltd.), the 50% particle size based on the volume distribution of the resin fine particles was 0.10 μm. The 90% particle size was 0.14 μm.

<Aqueous dispersion of styrene-acrylic copolymer A (emulsion polymerization)>
Styrene 300 parts by mass n-butyl acrylate 150 parts by mass Acrylic acid 3 parts by mass n-dodecyl mercaptan 10 parts by mass The above components were mixed to prepare a monomer solution, and an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: A surfactant aqueous solution in which 10 parts by mass of Neogen RK) is dissolved in 1130 parts by mass of ion-exchanged water and the monomer solution are placed in a two-necked flask and rotated using a homogenizer (IKA: Ultra Turrax T50). The mixture was stirred at several 10000 rpm for emulsification. Thereafter, the inside of the flask was purged with nitrogen, heated in a water bath with slow stirring until the content reached 70 ° C., and then 7 parts of ion-exchanged water in which 3 parts of ammonium persulfate had been dissolved was added to initiate polymerization. After the reaction was continued for 8 hours, the reaction solution was cooled to room temperature. As a result, a styrene-acrylic polymer having an average particle size of 150 nm, a glass transition temperature of 46 ° C., a weight average molecular weight Mw of 30,000 and Mw / Mn of 2.6. A copolymer A dispersion was obtained.

<Preparation of resin fine particle dispersion having second resin>
(Aqueous dispersion of polyester resin D)
Polyester resin D ((composition (molar ratio) / polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane: ethylene glycol: terephthalic acid: maleic acid: trimellitic acid = 35: 15: 33: 15: 2), Mn; 4,600, Mw; 16,500, Mp; 10,400, Tg; 67 ° C., acid value: 10 mg KOH / g) (1200 parts by mass) and an anionic surfactant (No. Ichi Kogyo Seiyaku Co., Ltd .: Neogen SC-A) (0.5 parts by mass) was dissolved in THF (2400 parts by mass), and then dimethylaminoethanol (1 equivalent to the acid value of polyester resin D) was added. Stir for 10 minutes. Thereafter, ion-exchanged water (3600 parts by mass) was dropped using a homogenizer (manufactured by IKA: Ultra Tarrax T50) while stirring at a rotational speed of 5000 rpm. The obtained mixture was treated under reduced pressure (50 mmHg) at 50 ° C. to remove THF, and an aqueous dispersion of polyester resin D was obtained (solid content concentration: 25 wt%). When the particle size of the obtained aqueous dispersion was measured with a laser diffraction / scattering type particle size distribution analyzer (LA-920: manufactured by Horiba, Ltd.), the 50% particle size based on the volume distribution of the resin fine particles was 0.11 μm. The 90% particle size was 0.15 μm.

(Aqueous dispersion of polyester resin E)
Polyester resin E (((composition (molar ratio) / polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane: ethylene glycol: terephthalic acid: maleic acid: trimellitic acid = 35: 15 : 40: 8: 2), Mn; 4,800, Mw; 17,500, Tg; 75 ° C., acid value: 12 mg KOH / g) (1200 parts by mass) and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd.) : Neogen SC-A) (0.5 parts by mass) was dissolved in THF (2400 parts by mass), dimethylaminoethanol (1 equivalent to the acid value of polyester resin E) was added, and the mixture was stirred for 10 minutes. Thereafter, ion-exchanged water (3600 parts by mass) was added dropwise with stirring at a rotational speed of 5000 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50). The resulting mixture was treated at 50 ° C. under reduced pressure (50 mmHg) to remove THF to obtain an aqueous dispersion of polyester resin E (solid content concentration: 25 wt%). When the particle size of the aqueous dispersion was measured with a laser diffraction / scattering type particle size distribution analyzer (LA-920: manufactured by HORIBA, Ltd.), the 50% particle size based on the volume distribution of the resin fine particles was 0.13 μm, The 90% particle size was 0.17 μm.

(Aqueous dispersion of polyester resin F)
Polyester resin F ((composition (molar ratio) / polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane): ethylene glycol: terephthalic acid: maleic acid: trimellitic acid = 35: 15: 27: 21: 2), Mn; 4,200, Mw; 15,100, Tg; 63 ° C., acid value: 15 mg KOH / g) (1200 parts by mass) and an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC-A) (0.5 parts by mass) was dissolved in THF (2400 parts by mass), dimethylaminoethanol (1 equivalent to the acid value of the polyester resin F) was added, and the mixture was stirred for 10 minutes. Thereafter, ion-exchanged water (3600 parts by mass) was dropped using a homogenizer (manufactured by IKA: Ultra Tarrax T50) while stirring at a rotational speed of 5000 rpm. The obtained mixture was treated at 50 ° C. under reduced pressure (50 mmHg) to remove THF, and an aqueous dispersion of polyester resin F was obtained (solid content concentration: 25 wt%). When the particle size of the obtained aqueous dispersion was measured with a laser diffraction / scattering particle size distribution measuring device (LA-920: manufactured by Horiba, Ltd.), the 50% particle size based on the volume distribution of the resin fine particles was 0.15 μm. The 90% particle size was 0.20 μm.

<Aqueous dispersion of styrene-acrylic copolymer B (emulsion polymerization)>
Styrene 400 parts by mass n-butyl acrylate 100 parts by mass Acrylic acid 3 parts by mass n-dodecyl mercaptan 10 parts by mass The above components were mixed to prepare a monomer solution, and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: A surfactant aqueous solution in which 10 parts of Neogen RK) are dissolved in 1130 parts of ion-exchanged water and the monomer solution are put into a two-necked flask, and the number of revolutions is 10,000 rpm using a homogenizer (manufactured by IKA: Ultra Turrax T50). The mixture was stirred and emulsified. Thereafter, the inside of the flask was purged with nitrogen, heated in a water bath with slow stirring until the content reached 70 ° C., and then 7 parts of ion-exchanged water in which 3 parts of ammonium persulfate had been dissolved was added to initiate polymerization. After the reaction was continued for 8 hours, the reaction solution was cooled to room temperature. As a result, the 50% particle size based on the volume distribution of the resin fine particles was 180 nm, the glass transition temperature was 66.0 ° C., the weight average molecular weight Mw was 31,000, A styrene-acrylic copolymer B dispersion having a / Mn of 2.6 was obtained.

<Preparation of aqueous dispersion of colorant>
(Aqueous dispersion of colorant fine particles)
Cyan pigment (manufactured by Dainichi Seika Co., Ltd .: Pigment Blue 15: 3) 100 parts by weight anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 15 parts by weight ion-exchanged water 885 parts by weight An aqueous dispersion of fine colorant particles was prepared by dispersing the colorant for about 1 hour using a high-pressure impact disperser Nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.). The 50% particle size based on volume distribution of the colorant fine particles was 0.19 μm, and the 90% particle size was 0.26 μm.

<Preparation of aqueous dispersion of release agent>
(Aqueous dispersion of release agent fine particles)
Ester wax (behenyl behenate, melting point 75 ° C.) 100 parts by weight anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 10 parts by weight ion-exchanged water 880 parts by weight The above was put into a mixing vessel equipped with a stirrer. After heating to 90 ° C and circulating to Claremix W Motion (M Technique Co., Ltd.), the rotor rotating speed was 19000 rpm and the screen rotating speed was 19000 rpm at a shearing stirrer with a rotor outer diameter of 3 cm and clearance of 0.3 mm. The mixture was dispersed for 60 minutes and then cooled to 40 ° C. under cooling conditions of a rotor rotation speed of 1000 rpm, a screen rotation speed of 0 rpm, and a cooling rate of 10 ° C./min. A dispersion was obtained. The 50% particle size based on the volume distribution of the release agent fine particles was 0.22 μm, and the 90% particle size was 0.29 μm.

<Compatibility evaluation 1>
Equal amounts of polyester resin A and polyester resin D were mixed and melt kneaded for 2 hours at a treatment temperature of 200 ° C. using a heating roll. Then, it cooled to room temperature, and when the dynamic viscoelasticity of the obtained resin was evaluated by the said method, it had one maximum value when tangent loss (tan-delta) was 40 degreeC or more and less than 100 degreeC.

<Compatibility evaluation 2>
Equal amounts of polyester resin B and polyester resin D were mixed and melt kneaded for 2 hours at a treatment temperature of 200 ° C. using a heating roll. Then, it cooled to room temperature, and when the dynamic viscoelasticity of the obtained resin was evaluated by the said method, it had one maximum value when tangent loss (tan-delta) was 40 degreeC or more and less than 100 degreeC.

<Compatibility evaluation 3>
Equal amounts of polyester resin C and polyester resin D were mixed and melt kneaded for 2 hours at a treatment temperature of 200 ° C. using a heating roll. Then, it cooled to room temperature, and when the dynamic viscoelasticity of the obtained resin was evaluated by the said method, it had one maximum value when tangent loss (tan-delta) was 40 degreeC or more and less than 100 degreeC.

<Compatibility evaluation 4>
Equal amounts of polyester resin A and polyester resin E were mixed and melt kneaded for 2 hours at a treatment temperature of 200 ° C. using a heating roll. Then, it cooled to room temperature, and when the dynamic viscoelasticity of the obtained resin was evaluated by the said method, it had one maximum value when tangent loss (tan-delta) was 40 degreeC or more and less than 100 degreeC.

<Compatibility evaluation 5>
Equal amounts of polyester resin A and polyester resin F were mixed and melt-kneaded for 2 hours at a treatment temperature of 200 ° C. using a heating roll. Then, it cooled to room temperature, and when the dynamic viscoelasticity of the obtained resin was evaluated by the said method, it had one maximum value when tangent loss (tan-delta) was 40 degreeC or more and less than 100 degreeC.

<Compatibility evaluation 6>
Equal amounts of styrene-acrylic resin A and styrene-acrylic resin B were mixed and melt kneaded for 2 hours at a treatment temperature of 200 ° C. using a heating roll. Then, it cooled to room temperature, and when the dynamic viscoelasticity of the obtained resin was evaluated by the said method, it had one maximum value when tangent loss (tan-delta) was 40 degreeC or more and less than 100 degreeC.

<Compatibility evaluation 7>
Equal amounts of polyester resin A and styrene-acrylic resin B were mixed and melt kneaded for 2 hours at a treatment temperature of 200 ° C. using a heating roll. Then, it cooled to room temperature, and when the dynamic viscoelasticity of the obtained resin was evaluated by the said method, it had two maximum values when tangent loss (tan-delta) was 40 degreeC or more and less than 100 degreeC.

<Preparation of toner particles>
Example 1
<Core aggregation process>
Aqueous dispersion of polyester resin A 600 parts by weight Colorant fine particle aqueous dispersion 75 parts by weight Release agent fine particle aqueous dispersion 150 parts by weight 1% by weight Magnesium sulfate aqueous solution 150 parts by weight Ion-exchanged water 525 parts by weight Each of the above components Was added to a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then mixed with a stirring blade in a heating oil bath. The mixture was heated to 43 ° C. while appropriately adjusting the number of revolutions so as to be stirred. After maintaining at 43 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle size of about 5.3 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 90 ° C. and kept for 3 hours while continuing stirring. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was put in the water bath, and the core particles were cooled to 25 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of polyester resin D was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the temperature was raised to 40 ° C. and the mixture was stirred for 1 hour. Then, 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. The aqueous solution was added, the temperature was raised to 60 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was colorless and transparent, and it confirmed that the detachment | desorption of the polyester resin D in a fusion | melting process did not occur. Thereafter, the filtrate was sufficiently washed with ion-exchanged water, but it was confirmed that the filtrate was colorless and transparent even in the washing step, and the polyester resin D was not detached. Thereafter, toner particles 1 were obtained by drying using a vacuum dryer.

When the toner particles 1 were measured by the above Coulter Multisizer II (manufactured by Coulter Inc.), the weight average particle diameter D4 was 5.58 μm and the number average particle diameter D1 was 4.88 μm. That is, D4 / D1 was 1.14, and the toner particles 1 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it had two maximum values when the tangent loss (tan δ) was less than 100 ° C., and the maximum value on the low temperature side derived from the polyester resin A was The maximum value on the high temperature side derived from the polyester resin D at 56 ° C. was 87 ° C. Next, the toner particles 1 of the present invention were prepared by mixing the toner particles 1 with 1.7% by mass of hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g.

(Example 2)
In Example 1, toner particles 2 were obtained in the same manner as in Example 1 except that the aqueous dispersion of polyester resin D was changed from 90 parts by mass to 120 parts by mass. The weight average particle diameter D4 was 6.11 μm, and the number average particle diameter D1 was 5.25 μm. That is, D4 / D1 was 1.16, and the toner particles 2 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it had two maximum values when the tangent loss (tan δ) was less than 100 ° C., and the maximum value on the low temperature side derived from the polyester resin A was The maximum value on the high temperature side derived from the polyester resin D at 56 ° C. was 87 ° C. Next, the toner particles 2 of the present invention were prepared by mixing the toner particles 2 with 1.7% by mass of a hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g.

(Example 3)
In Example 1, toner particles 3 were obtained in the same manner as in Example 1 except that the aqueous dispersion of polyester resin D was changed from 90 parts by mass to 30 parts by mass. The weight average particle diameter D4 was 5.50 μm, and the number average particle diameter D1 was 4.79 μm. That is, D4 / D1 was 1.15, and the toner particles 3 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it had two maximum values when the tangent loss (tan δ) was less than 100 ° C., and the maximum value on the low temperature side derived from the polyester resin A was The maximum value on the high temperature side derived from the polyester resin D at 56 ° C. was 87 ° C. Next, the toner particles 3 of the present invention were prepared by mixing the toner particles 3 with 1.7% by mass of hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g.

Example 4
<Core aggregation process>
Aqueous dispersion of polyester resin B 600 parts by weight Colorant fine particle aqueous dispersion 75 parts by weight Release agent fine particle aqueous dispersion 150 parts by weight 1% by weight Magnesium sulfate aqueous solution 150 parts by weight Deionized water 525 parts by weight Each of the above components Was added to a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then mixed with a stirring blade in a heating oil bath. The mixture was heated to 35 ° C. while appropriately adjusting the number of revolutions so as to be stirred. After maintaining at 35 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle diameter of about 5.4 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 90 ° C. and kept for 3 hours while continuing stirring. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was placed in the water bath, and the core particles were cooled to 20 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of polyester resin D was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 30 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 30 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the mixture was heated to 35 ° C. and stirred for 1 hour, and then 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. An aqueous solution was added, the temperature was raised to 45 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was colorless and transparent, and it confirmed that the detachment | desorption of the polyester resin D in a fusion | melting process did not occur. Thereafter, the filtrate was sufficiently washed with ion-exchanged water, but it was confirmed that the filtrate was colorless and transparent even in the washing step, and the polyester resin D was not detached. Thereafter, toner particles 4 were obtained by drying using a vacuum dryer.

When the toner particles 4 were measured by the above Coulter Multisizer II (manufactured by Coulter Inc.), the weight average particle diameter D4 was 5.66 μm, and the number average particle diameter D1 was 4.91 μm. That is, D4 / D1 was 1.15, and the toner particles 4 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-mentioned method, it had two maximum values when the tangent loss (tan δ) was less than 100 ° C., and the maximum value on the low temperature side derived from the polyester resin B was The maximum value on the high temperature side derived from the polyester resin D at 48 ° C. was 87 ° C. Next, the toner particles 4 of the present invention were prepared by mixing the toner particles 4 with 1.7% by mass of hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g.

(Example 5)
<Core aggregation process>
Aqueous dispersion of polyester resin C 600 mass parts Aqueous dispersion of colorant fine particles 75 mass parts Aqueous dispersion of release agent fine particles 150 mass parts 1 mass% magnesium sulfate aqueous solution 150 mass parts ion-exchanged water 525 mass parts Each of the above components Was added to a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then mixed with a stirring blade in a heating oil bath. The mixture was heated to 48 ° C. while appropriately adjusting the number of revolutions so as to be stirred. After maintaining at 48 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle diameter of about 5.4 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 90 ° C. and kept for 3 hours while continuing stirring. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was put in the water bath, and the core particles were cooled to 25 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of polyester resin D was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the mixture was heated to 40 ° C. and stirred for 1 hour, and then 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. An aqueous solution was added, the temperature was raised to 65 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was colorless and transparent, and it confirmed that the detachment | desorption of the polyester resin D in a fusion | melting process did not occur. Thereafter, the filtrate was sufficiently washed with ion-exchanged water, but it was confirmed that the filtrate was colorless and transparent even in the washing step, and the polyester resin D was not detached. Thereafter, toner particles 5 were obtained by drying using a vacuum dryer.

When the toner particles 5 were measured by the above Coulter Multisizer II (manufactured by Coulter Inc.), the weight average particle diameter D4 was 5.60 μm and the number average particle diameter D1 was 4.89 μm. That is, D4 / D1 was 1.15, and the toner particles 5 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it has two maximum values when the tangent loss (tan δ) is less than 100 ° C., and the maximum value on the low temperature side derived from the polyester resin C is The maximum value on the high temperature side derived from the polyester resin D at 63 ° C. was 87 ° C. Next, the toner 5 of the present invention was prepared by mixing the toner particles 5 with 1.7% by mass of a hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g.

(Example 6)
<Core aggregation process>
Aqueous dispersion of polyester resin A 600 parts by weight Colorant fine particle aqueous dispersion 75 parts by weight Release agent fine particle aqueous dispersion 150 parts by weight 1% by weight Magnesium sulfate aqueous solution 150 parts by weight Ion-exchanged water 525 parts by weight Each of the above components Was added to a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then mixed with a stirring blade in a heating oil bath. The mixture was heated to 45 ° C. while appropriately adjusting the number of revolutions so as to be stirred. After maintaining at 45 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle diameter of about 5.4 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 90 ° C. and kept for 3 hours while continuing stirring. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was put in the water bath, and the core particles were cooled to 25 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of polyester resin E was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the mixture was heated to 40 ° C. and stirred for 1 hour, and then 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. An aqueous solution was added, the temperature was raised to 65 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was colorless and transparent, and it confirmed that the detachment | desorption of the polyester resin E in a fusion process did not occur. Thereafter, the filtrate was sufficiently washed with ion-exchanged water, but it was confirmed that the filtrate was colorless and transparent even in the washing step, and the polyester resin E was not detached. Thereafter, toner particles 6 were obtained by drying using a vacuum dryer.

When the toner particles 6 were measured by the above Coulter Multisizer II (manufactured by Coulter Inc.), the weight average particle diameter D4 was 5.82 μm and the number average particle diameter D1 was 5.09 μm. That is, D4 / D1 was 1.14, and the toner particles 6 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it had two maximum values when the tangent loss (tan δ) was less than 100 ° C., and the maximum value on the low temperature side derived from the polyester resin A was The maximum value on the high temperature side derived from the polyester resin E at 56 ° C. was 96 ° C. Next, toner particles 6 of the present invention were prepared by mixing the toner particles 6 with 1.7% by mass of hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g.

(Example 7)
<Core aggregation process>
Aqueous dispersion of polyester resin A 600 parts by weight Colorant fine particle aqueous dispersion 75 parts by weight Release agent fine particle aqueous dispersion 150 parts by weight 1% by weight Magnesium sulfate aqueous solution 150 parts by weight Ion-exchanged water 525 parts by weight Each of the above components Was added to a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then mixed with a stirring blade in a heating oil bath. The mixture was heated to 45 ° C. while appropriately adjusting the number of revolutions so as to be stirred. After maintaining at 45 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle diameter of about 5.4 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 90 ° C. and kept for 3 hours while continuing stirring. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was put in the water bath, and the core particles were cooled to 25 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of polyester resin F was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the mixture was heated to 40 ° C. and stirred for 1 hour, and then 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. An aqueous solution was added, the temperature was raised to 65 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was colorless and transparent, and it confirmed that the detachment | desorption of the polyester resin F in a fusion process did not occur. Thereafter, the filtrate was sufficiently washed with ion-exchanged water, but it was confirmed that the filtrate was colorless and transparent even in the washing step, and the polyester resin F was not detached. Thereafter, toner particles 7 were obtained by drying using a vacuum dryer.

The toner particles 7 were measured by the above Coulter Multisizer II (manufactured by Coulter Inc.). As a result, the weight average particle diameter D4 was 5.80 μm and the number average particle diameter D1 was 5.05 μm. That is, D4 / D1 was 1.15, and the toner particles 7 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it had two maximum values when the tangent loss (tan δ) was less than 100 ° C., and the maximum value on the low temperature side derived from the polyester resin A was The maximum value on the high temperature side derived from the polyester resin F at 56 ° C. was 82 ° C. Next, the toner particles 7 according to the present invention were prepared by mixing the toner particles 7 with 1.7% by mass of hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g.

(Example 8)
<Core aggregation process>
Aqueous dispersion of styrene-acrylic resin A 600 mass parts Aqueous dispersion of colorant fine particles 75 mass parts Aqueous dispersion of release agent fine particles 150 mass parts 1 mass% magnesium sulfate aqueous solution 150 mass parts ion-exchanged water 525 mass parts Each component was put into a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (IKA: Ultra Tarrax T50), and then using a stirring blade in a heating oil bath, It heated to 43 degreeC, adjusting suitably the rotation speed so that a liquid mixture might be stirred. After maintaining at 43 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle diameter of about 5.4 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 95 ° C. while being stirred, and maintained for 3 hours. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was put in the water bath, and the core particles were cooled to 25 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of styrene-acrylic resin B was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the mixture was heated to 40 ° C. and stirred for 1 hour, and then 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. An aqueous solution was added, the temperature was raised to 60 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was colorless and transparent, and it confirmed that detachment | desorption of the styrene-acrylic resin B in a fusion | melting process did not occur. Thereafter, the filtrate was sufficiently washed with ion-exchanged water, but it was confirmed that the filtrate was colorless and transparent even in the washing step, and the styrene-acrylic resin B was not detached. Thereafter, toner particles 8 were obtained by drying using a vacuum dryer.

  When the toner particles 8 were measured by the above Coulter Multisizer II (manufactured by Coulter Inc.), the weight average particle diameter D4 was 5.56 μm and the number average particle diameter D1 was 4.80 μm. That is, D4 / D1 was 1.16, and the toner particles 8 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it had two maximum values when the tangent loss (tan δ) was less than 100 ° C., and the maximum on the low temperature side derived from the styrene-acrylic resin A. The value was 62 ° C., and the maximum value on the high temperature side derived from the styrene-acrylic resin B was 96 ° C.

Next, the toner particles 8 of the present invention were prepared by mixing the toner particles 8 with 1.7% by mass of hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g.

(Comparative Example 1)
Polyester resin A aqueous dispersion 600 parts by weight Colorant dispersion 75 parts by weight Release agent dispersion 150 parts by weight 1% by weight Magnesium sulfate aqueous solution 150 parts by weight ion-exchanged water 525 parts by weight Each of the above components is a round stainless steel flask The mixture is mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (IKA: Ultra Tarrax T50), and then the mixture is rotated using a stirring blade in a heating oil bath. The sample was heated to 43 ° C. while adjusting the number appropriately. After maintaining at 43 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that aggregated particles having a volume average particle diameter of about 5.1 μm were formed.

  When 180 parts by mass of the polyester resin D dispersion is added dropwise to the above aggregated particles and further treated at 43 ° C. for 1 hour, aggregated particles having a volume average particle diameter of about 5.1 μm are formed. confirmed. In this state, a small amount of the reaction solution was extracted as needed and passed through a 2 μm microfilter to confirm that the filtrate became transparent. After confirming that the newly added polyester resin D was sufficiently adhered, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water. While continuing, it was heated to 90 ° C. and held for 3 hours. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and coalesced particles having a volume average particle diameter of about 5.2 μm and a circularity of 0.980 were formed. When cooled to room temperature and filtered, the filtrate was colorless and transparent, and it was confirmed that the polyester resin D was not detached in the fusion process. Thereafter, the filtrate was sufficiently washed with ion-exchanged water, but it was confirmed that the filtrate was colorless and transparent even in the washing step, and the polyester resin D was not detached. Then, comparative toner particles 1 were obtained by drying using a vacuum dryer.

When the comparative toner particles 1 were measured by the above Coulter Multisizer II (manufactured by Coulter Inc.), the weight average particle diameter D4 was 5.20 μm and the number average particle diameter D1 was 4.50 μm. That is, D4 / D1 was 1.16, and the comparative toner particle 1 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above method, it had one maximum value when the tangent loss (tan δ) was 40 ° C. or higher and lower than 100 ° C. Next, the comparative toner particle 1 was mixed with 1.7% by mass of a hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g to prepare the comparative toner 1 of the present invention. .

(Comparative Example 2)
Comparative toner particles 2 were obtained in the same manner as in Comparative Example 1, except that the aqueous dispersion of polyester resin D was changed from 90 parts by weight to 180 parts by weight in Comparative Example 1. The weight average particle diameter D4 was 6.11 μm, and the number average particle diameter D1 was 5.25 μm. That is, D4 / D1 was 1.16, and the toner particles 2 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it had one maximum value when the tangent loss (tan δ) was 40 ° C. or higher and lower than 100 ° C. Next, 1.7% by mass of a hydrophobic silica fine powder (primary average particle diameter 0.01 μm) having a BET specific surface area of 200 m ² / g was mixed with the comparative toner particles 2 to prepare the comparative toner 2 of the present invention. .

(Comparative Example 3)
<Core aggregation process>
Aqueous dispersion of polyester resin A 600 parts by weight Colorant fine particle aqueous dispersion 75 parts by weight Release agent fine particle aqueous dispersion 150 parts by weight 1% by weight Magnesium sulfate aqueous solution 150 parts by weight Ion-exchanged water 525 parts by weight Each of the above components Was added to a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then mixed with a stirring blade in a heating oil bath. The mixture was heated to 43 ° C. while appropriately adjusting the number of revolutions so as to be stirred. After maintaining at 43 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle size of about 5.3 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 90 ° C. and kept for 3 hours while continuing stirring. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was put in the water bath, and the core particles were cooled to 25 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of polyester resin D was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the mixture was heated to 40 ° C. and stirred for 1 hour, and then 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. An aqueous solution was added, the temperature was raised to 80 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was colorless and transparent, and it confirmed that the detachment | desorption of the polyester resin D in a fusion | melting process did not occur. Thereafter, the filtrate was sufficiently washed with ion-exchanged water, but it was confirmed that the filtrate was colorless and transparent even in the washing step, and the polyester resin D was not detached. Then, comparative toner particles 3 were obtained by drying using a vacuum dryer.

When the comparative toner particles 3 were measured by the above Coulter Multisizer II (manufactured by Coulter Inc.), the weight average particle diameter D4 was 5.58 μm and the number average particle diameter D1 was 4.88 μm. That is, D4 / D1 was 1.14, and the comparative toner particle 3 showed a sharp particle size distribution. When the dynamic viscoelasticity of the toner particles was measured by the above-described method, it had one maximum value when the tangent loss (tan δ) was 40 ° C. or higher and lower than 100 ° C. Next, 1.7% by mass of hydrophobic silica fine powder (primary average particle size 0.01 μm) having a BET specific surface area of 200 m ² / g was mixed with the comparative toner particles 3 to prepare the comparative toner 3 of the present invention. .

(Comparative Example 4)
<Core aggregation process>
Aqueous dispersion of polyester resin A 600 parts by weight Colorant fine particle aqueous dispersion 75 parts by weight Release agent fine particle aqueous dispersion 150 parts by weight 1% by weight Magnesium sulfate aqueous solution 150 parts by weight Ion-exchanged water 525 parts by weight Each of the above components Was added to a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then mixed with a stirring blade in a heating oil bath. The mixture was heated to 43 ° C. while appropriately adjusting the number of revolutions so as to be stirred. After maintaining at 43 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle size of about 5.3 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 90 ° C. and kept for 3 hours while continuing stirring. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was put in the water bath, and the core particles were cooled to 25 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of polyester resin D was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the mixture was heated to 40 ° C. and stirred for 1 hour, and then 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. An aqueous solution was added, the temperature was raised to 40 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was cloudy and the detachment | desorption of the polyester resin D in the fusion process was confirmed. Thereafter, the filtrate was sufficiently washed with ion-exchanged water. However, in the washing step, the filtrate was cloudy, and it was confirmed that the polyester resin D was detached.

(Comparative Example 5)
<Core aggregation process>
Aqueous dispersion of polyester resin A 600 parts by weight Colorant fine particle aqueous dispersion 75 parts by weight Release agent fine particle aqueous dispersion 150 parts by weight 1% by weight Magnesium sulfate aqueous solution 150 parts by weight Ion-exchanged water 525 parts by weight Each of the above components Was added to a round stainless steel flask, mixed and dispersed at 5000 rpm for 10 minutes using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then mixed with a stirring blade in a heating oil bath. The mixture was heated to 43 ° C. while appropriately adjusting the number of revolutions so as to be stirred. After maintaining at 43 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that core aggregated particles having a volume average particle size of about 5.3 μm were formed.

<Primary fusion process>
Thereafter, an aqueous solution in which 15 parts by mass of trisodium citrate was dissolved was added to 285 parts by mass of ion-exchanged water, and then heated to 90 ° C. and kept for 3 hours while continuing stirring. The volume average particle diameter and circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united core particles having a volume average particle diameter of about 5.4 μm and a circularity of 0.980 were formed.

<Cooling process>
Next, while stirring was continued, water was put in the water bath, and the core particles were cooled to 25 ° C.

<Shell adhesion process>
Next, 90 parts by mass of an aqueous dispersion of styrene-acrylic resin B was added. Then, it stirred with the stirring blade for 10 minutes, and also 340 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the reaction solution was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent (until the shell fine particles were sufficiently attached to the core particles).

<Secondary fusion process>
After confirming that the filtrate became transparent, the mixture was heated to 40 ° C. and stirred for 1 hour, and then 12.5 parts by mass of trisodium citrate was dissolved in 237.5 parts by mass of ion-exchanged water. An aqueous solution was added, the temperature was raised to 60 ° C., and the mixture was stirred for 1.5 hours. Then, when it cooled and filtered to room temperature, the filtrate was cloudy and the detachment | desorption of the styrene-acrylic resin B in the fusion process was confirmed. Thereafter, the filtrate was sufficiently washed with ion-exchanged water. However, in the washing step, the filtrate was cloudy, and it was confirmed that styrene-acrylic resin B was detached.

[Toner evaluation]
The following evaluation was performed using the toners 1 to 8 and the comparative toners 1 to 3. The results are shown in Table 1.

<Evaluation of heat-resistant storage stability>
A: No agglomerates are observed even after standing for 1 day under a temperature condition 5 ° C. higher than the glass transition point (Tg1) of the first resin.
B: No agglomerates are observed even after standing for 1 day under the temperature condition of the glass transition point (Tg1) of the first resin.
C: Aggregates are observed when allowed to stand for 1 day under the temperature condition of the glass transition point (Tg1) of the first resin.

<Evaluation of fixability>
Each toner and a ferrite carrier surface-coated with a silicone resin (average particle diameter 42 μm) were mixed so that the toner concentration was 10% by mass to prepare a two-component developer. A commercially available full color digital copying machine (CLC1100, manufactured by Canon Inc.) was used to form an unfixed toner image (0.6 mg / cm ² ) on image receiving paper (64 g / m ² ). A fixing unit removed from a commercially available color laser printer (LBP-5500, manufactured by Canon Inc.) was remodeled so that the fixing temperature could be adjusted, and a fixing test of an unfixed image was performed using this. Under normal temperature and normal humidity, the process speed was set to 180 mm / second, the fixing member set temperature was adjusted in the range of 70 ° C. to 150 ° C. at intervals of 10 ° C., and a fixing test for unfixed images was performed. The lowest fixing temperature (minimum fixing temperature) at which no cold offset occurred was visually evaluated according to the following criteria.
A: The minimum fixing temperature is less than 90 ° C.
B: The minimum fixing temperature is 90 ° C. or higher and lower than 110 ° C.
C: The minimum fixing temperature is 110 ° C. or higher and lower than 130 ° C.
D: The minimum fixing temperature is 130 ° C. or higher.

  Regarding Comparative toners 4 to 5, the core particles were not sufficiently covered with the shell particles, and the required blocking resistance could not be ensured, so that the fixability evaluation was impossible.

Claims (6)

A core-shell toner obtained by an emulsion aggregation method, having core particles containing a first resin and a colorant, and a shell layer containing a second resin,
The first resin and the second resin have compatibility,
The mass ratio of the second resin to the first resin in the core-shell toner is 3% by mass or more and 20% by mass or less.
A core-shell toner characterized in that the tangent loss (tan δ) of dynamic viscoelasticity of the core-shell toner has either a maximum value or a shoulder in the range of 40 ° C. or more and less than 100 ° C.   The tangent loss (tan δ) of the dynamic viscoelasticity of the core-shell toner has one maximum value or shoulder at 40 ° C. or more and less than 70 ° C., and one maximum value or shoulder at 70 ° C. or more and less than 100 ° C. The core-shell toner according to claim 1.   The core-shell toner according to claim 1, wherein the first resin and the second resin are polyester resins. An aqueous dispersion of first resin fine particles having the first resin and an aqueous dispersion of the colorant are mixed, and the first resin fine particles and the colorant are aggregated in an aqueous medium to form a core aggregate. A core agglomeration step to form particles;
A primary fusion step of heating the core aggregated particles to a glass transition point Tg1 or higher of the first resin and fusing them to obtain core particles;
A cooling step of cooling the temperature of the aqueous medium containing the core particles to a temperature lower than the Tg1,
Shell adhesion in which an aqueous dispersion of second resin fine particles having a second resin and an aggregating agent are mixed at a temperature lower than Tg1, and second resin fine particles are adhered to the core particles to obtain a shell adhering body. Process,
4. The method according to claim 1, wherein the shell adhering body is obtained by a production method including a secondary fusion step in which the shell adhering body is heated at Tg1 or more and at or below the glass transition point Tg2 of the second resin. The core shell toner described in 1.   The core-shell toner according to claim 4, wherein the Tg1 is 30 ° C. or more and 60 ° C. or less.   The core-shell toner according to claim 4, wherein the Tg2 is 60 ° C. or higher and 80 ° C. or lower.