JP5430168B2 - toner - Google Patents

Description

  The present invention relates to a toner used to form a toner image by developing an electrostatic latent image formed by a method such as electrophotography, electrostatic recording, or toner jet recording.

  In recent years, printers and copiers are required to increase the resolution of images by digitization, and at the same time, increase the printing or copying speed, or save space and reduce power consumption by downsizing the apparatus. . In order to satisfy such demands for higher speed and lower power consumption, improvement in the fixing performance of the toner itself is also required. That is, it is desired to realize a toner that can be fixed at a lower temperature.

  As a general method for improving the low-temperature fixability of the toner, a method of lowering the glass transition temperature of the binder resin constituting the toner is known. However, simply lowering the glass transition temperature decreases the heat-resistant storage stability of the toner, and when used in a high-temperature environment, the toner that agglomerates between the toners that come into contact with each other tends to cause a blocking phenomenon. Arise.

  In order to solve these problems, a capsule structure composed of core particles containing a resin having a low glass transition temperature and an outer shell containing a resin having a high glass transition temperature formed so as to cover the surface of the core particles. Toners have been devised.

  In particular, the method of forming the coating layer by fixing the resin fine particles after forming the core particles is effective as a method for improving the heat resistant storage stability without impairing the low-temperature fixability.

  For example, an aqueous dispersion of resin fine particles obtained by emulsion polymerization or soap-free emulsion polymerization is added to the core particles obtained by suspension polymerization to cover 95% or more of the surface of the core particles with the resin fine particles. A proposed toner is proposed (see Patent Document 1).

  In addition, an intermediate layer having a charging property opposite to that of the core particle is formed on the surface of the core particle, and resin fine particles having a charging property opposite to that of the intermediate layer obtained by emulsion polymerization are fixed to the surface of the intermediate layer. A toner having a coating layer formed thereon is proposed (see Patent Document 2).

  In addition, a coating layer is formed by agglomerating resin fine particles having a functional group concentration lower than that of the core particles on the surface of the core particles obtained by emulsifying and aggregating a polyester resin containing a large amount of hydrophilic functional groups. Toner has been proposed. (See Patent Document 3).

  In addition, a toner has been proposed in which production stability is maintained while suppressing the amount of surfactant used by emulsifying and aggregating polyester resin fine particles containing carboxyl groups and sulfonic acid groups (see Patent Document 4).

  In the toner disclosed in Patent Document 1 described above, it is necessary to use a surfactant in order to make the resin fine particles into a water-dispersed state, or to add a large amount of functional groups to the resin even if no surfactant is used. there were. For this reason, the hydrophilicity of the toner surface is increased, and as a result, there is a problem that the charge amount is likely to be reduced in a high humidity environment due to the influence of moisture. Furthermore, due to the influence of the surfactant and a large amount of functional groups, the adhesion strength of the resin fine particles to the core particles is not sufficient, and excellent heat-resistant storage stability cannot be achieved.

  Further, the toner disclosed in Patent Document 2 described above is produced by emulsion polymerization of resin fine particles used for the coating layer. Therefore, there has been a problem that the chargeability of the toner is lowered due to the influence of the surfactant used in the production process. Moreover, not only excellent chargeability is not obtained due to the influence of the intermediate layer, but also low temperature fixability may be hindered. As a result, it is not possible to achieve both excellent chargeability and low temperature fixability. It was.

  Further, the toner disclosed in Patent Document 3 described above lowers the hydrophilicity of the toner surface by reducing the concentration of the functional groups of the resin fine particles used in the coating layer. However, there is a problem that the chargeability of the toner is lowered due to the effect of lowering the concentration of the functional group. Furthermore, increasing the concentration of the functional group of the core particle increases the water absorption of the entire toner, and as a result, the stability of charging in a high humidity environment may be reduced.

  Further, in the toner disclosed in Patent Document 4 described above, by using resin fine particles containing a carboxyl group and a sulfonic acid group, a toner by emulsion aggregation can be stably produced without using a surfactant. The hydrophilicity of the toner surface can be suppressed because the content of the sulfonic acid group is small, but it does not have a capsule structure, and as a result, it cannot be compatible with low-temperature fixability and heat-resistant storage stability. There was a risk that the amount of water absorption would increase.

  As described above, a toner having toner particles having a capsule structure, which has both low-temperature fixability and heat-resistant storage stability, has a sufficient charge amount, and has a low charge amount decrease in a high-humidity environment. Yes.

JP 2000-112174 A JP2003-91093A JP-A-10-73955 JP 2006-267298 A

  An object of the present invention is to provide a toner that solves the above-described conventional problems.

  That is, an object of the present invention is to provide a toner that is excellent in low-temperature fixability and heat-resistant storage stability, can maintain a sufficient charge amount, and has a small decrease in charge amount in a high humidity environment.

The present invention is a toner containing toner particles having core particles containing at least a binder resin, a colorant and a release agent, and a coating layer covering the core particles,
The coating layer is formed by forming resin particles on the surface of the core particles after forming the core particles,
The difference (Tg2−Tg1) (° C.) between the glass transition temperature Tg1 (° C.) of the core particles and the glass transition temperature Tg2 (° C.) of the resin fine particles is 5 to 40 ° C.
The resin fine particle is composed of a resin containing at least a carboxyl group and a sulfonic acid group, and the acid value derived from the carboxyl group of the resin fine particle is 3.0 to 20.0 mgKOH / g, The acid value derived from the sulfonic acid group of the fine particle is 2.0 to 15.0 mg KOH / g, and the total of the acid value derived from the carboxyl group and the acid value derived from the sulfonic acid group of the resin fine particle is 8 0.0 to 30.0 mg KOH / g ,
The present invention relates to a toner characterized in that 0.005 to 0.050% by mass of sulfur element is contained in the coating layer with respect to the toner particles.

  According to the present invention, in a toner having toner particles having a capsule structure, a toner having both low-temperature fixability and heat-resistant storage stability, a sufficient charge amount, and a small decrease in charge amount in a high humidity environment is provided. can do.

It is a figure which shows the structure of the apparatus used for the measurement of the charge amount of the developing agent using the toner of this invention.

As a method for forming toner particles having a core-shell structure including a core particle and a coating layer covering the core particle, various methods have been studied.
For example, a solution obtained by dissolving a resin, which is a coating layer constituent material, is dispersed in a monomer, which is a raw material for core particles, or a resin, which constitutes the core particles, in a dispersion medium, and is coated as the core particles are formed. There is a method of forming a coating layer by unevenly distributing the layer constituting material on the surface of the droplet.

  Also, a method of adding the shear by mixing the resin particles that are the constituent material of the core particles and the coating layer, or adding an aqueous dispersion of the resin particles to the aqueous dispersion of the core particles, and if necessary, temperature, pH, time There is a method of forming a coating layer by attaching resin fine particles to the surface of the core particles by changing the control of the control and the conditions for adding the electrolyte flocculant.

  Among these, the method of forming a coating layer by adding an aqueous dispersion of resin fine particles to an aqueous dispersion of core particles and attaching the resin fine particles to the surface of the core particles can form a highly uniform and dense coating layer. Is the method.

  However, in order to obtain an aqueous dispersion in which resin fine particles are well dispersed, it is necessary to use a surfactant in the production process or to contain a large amount of hydrophilic functional groups in the resin constituting the resin fine particles. there were.

  When a coating layer is formed using such resin fine particles, the charge amount of the resulting toner may be significantly reduced due to the influence of the remaining surfactant and a large amount of hydrophilic functional groups, or in a high humidity environment. Under such conditions, the chargeability may decrease.

  Therefore, the present inventors have attempted to solve the above problems by paying attention to a functional group that imparts hydrophilicity to the resin constituting the resin fine particles. The sulfonic acid group contained in the resin fine particles has a property that the charge imparting ability to the toner is high. On the other hand, since the hydrophilic property is high, the sulfonic acid group is easily affected by moisture in a high humidity environment, and the chargeability is greatly reduced. On the other hand, the carboxyl group contained in the resin fine particles has a low ability to impart charge to the toner, but has a lower hydrophilicity than the sulfonic acid group, so it is less affected by moisture and less deteriorated in a high humidity environment. .

  If the resin fine particles contain the above-described sulfonic acid group and carboxyl group so that the respective excellent effects can be obtained, the resin fine particles have a sufficient charge amount and charge stability in a high humidity environment. A toner having a coating layer composed of the resin fine particles also exhibits excellent charging characteristics. The inventors of the present invention are able to achieve both low temperature fixability and heat-resistant storage stability at a high level with an excellent coating layer, and the durability and environmental stability for having excellent charging characteristics. The present invention was completed by considering that it was excellent.

  In the present invention, the conditions under which the sulfonic acid group and the carboxyl group exhibit an excellent effect and can impart sufficient water dispersibility to the resin fine particles are the results of completion of the present inventors' extensive studies. However, simple combinations and balance adjustments cannot be achieved at all.

  The present invention relates to a toner having toner particles having a core-shell structure including core particles containing at least a binder resin, a colorant, and a release agent, and a coating layer covering the core particles. And the resin which comprises this resin fine particle contains a carboxyl group and a sulfonic acid group at least.

  In the present invention, since the resin constituting the resin fine particles contains a carboxyl group and a sulfonic acid group, the resin fine particles can be obtained in a water-dispersed state without using a surfactant. As a result, the resin fine particles can be attached to the surface of the core particles in the aqueous medium, and a uniform and dense coating layer can be formed.

  Further, by using resin fine particles containing a sulfonic acid group, the chargeability of the toner is improved, and a desired charge amount can be obtained. Furthermore, by containing a carboxyl group, the amount of the sulfonic acid group can be suppressed while maintaining a good water dispersion state of the resin fine particles, so that the hydrophilicity of the resin fine particles can be lowered. As a result, it is possible to significantly improve the charging stability of the obtained toner in a high humidity environment.

  In the present invention, the sulfur element contained in the coating layer of the toner particles is mainly derived from the sulfonic acid group contained in the resin fine particles as the constituent material of the coating layer. The large amount of sulfur element contained means that the amount of sulfonic acid groups on the surface of the toner particles is large. In the present invention, the amount of sulfur element contained in the toner particle coating layer is 0.005 to 0.050 mass%. Thereby, a desired charge amount can be obtained, and a decrease in the charge amount in a high humidity environment can be suppressed. If the amount of sulfur element is less than 0.005% by mass, a sufficient charge amount may not be obtained. Further, when the amount of sulfur element is more than 0.050% by mass, a high charge amount can be obtained, but the charge amount may be reduced due to the influence of moisture in a high humidity environment. In addition, the measuring method of sulfur element amount is mentioned later.

  In the present invention, the difference (Tg2−Tg1) (° C.) between the glass transition temperature Tg1 (° C.) of the core particle in the toner particles and the glass transition temperature Tg2 (° C.) of the coating layer is in the range of 5 to 40 ° C. . When Tg2-Tg1 is in the above range, the core particles and the resin particles are sufficiently in close contact with each other while clearly maintaining layer separation, so that the resin particles and the core particles are compatible, the resin particles are buried, and the resin particles are peeled off. Such a phenomenon hardly occurs, and an excellent coating layer can be formed. As a result, it is possible to obtain a toner having improved heat storage stability without impairing the low-temperature fixability. When (Tg2−Tg1) (° C.) is less than 5 ° C., the compatibility between the core particles and the resin fine particles proceeds or the resin fine particles are buried when the coating layer is formed. Therefore, the resin fine particles substantially existing on the surface of the toner particles are reduced, and the excellent charging performance in the present invention cannot be obtained. When (Tg2-Tg1) (° C.) exceeds 40 ° C., the core particles and the resin fine particles are not sufficiently adhered, and the core particle components are exposed on the toner particle surfaces due to the peeling of the resin fine particles. In order to sufficiently adhere the core particles and the resin fine particles, when heated at a temperature significantly higher than the glass transition temperature of the core particles, the melt viscosity of the core particles decreases, and the compatibility between the core particles and the resin fine particles proceeds. As a result, resin fine particles existing on the toner particle surface are reduced or non-uniform, and thus excellent charging performance cannot be obtained.

  The glass transition temperature Tg1 (° C.) of the core particles is preferably 20 to 60 ° C. When the glass transition temperature Tg1 (° C.) of the core particles is within the above range, the effects of heat resistant storage stability and low temperature fixability can be further enhanced.

  The glass transition temperature Tg2 (° C.) of the resin fine particles in the present invention is preferably 50 to 120 ° C. When Tg2 is within the above range, sufficient heat storage stability and low-temperature fixability can be achieved.

  In addition, the measuring method of glass transition temperature is mentioned later.

  In the present invention, the total acid value of the resin fine particles is preferably 8.0 to 30.0 mgKOH / g. When the acid value is higher than 8.0 mgKOH / g, the resin fine particles can be kept in a water-dispersed state, or the chargeability of the obtained toner can be prevented from being lowered. When the acid value is lower than 30.0 mgKOH / g, it is possible to prevent the charging stability of the obtained toner from being deteriorated in a high humidity environment.

  The acid value measurement method will be described later.

  Of the acid values contained in the resin fine particles, the acid value derived from the sulfonic acid group is preferably 2.0 to 15.0 mgKOH / g. If the acid value derived from the sulfonic acid group is within the above range, an appropriate charge amount can be obtained, and the charge amount is hardly lowered due to the influence of moisture in a high humidity environment.

  Further, among the acid values contained in the resin fine particles, if the acid value derived from the carboxyl group is 3.0 to 20.0 mgKOH / g, the sulfonic acid group can be charged in a high humidity environment without hindering the charging property. It is possible to prevent a decrease in the amount of charge due to the influence of moisture.

  Of the acid values contained in the resin fine particles, the acid value derived from the sulfonic acid group is subjected to quantitative analysis of sulfur element contained in the resin using a fluorescent X-ray analyzer (XRF) described later, Calculate by calculation. The acid value derived from the carboxyl group can be obtained by calculating the difference in the acid value derived from the sulfonic acid contained in the resin fine particles from the acid value contained in the resin fine particles.

  As described above, the toner of the present invention controls the amount of carboxyl group and amount of sulfonic acid group contained in the resin fine particles for forming the coating layer, and can obtain excellent chargeability. The toner of the present invention has a dense coating layer formed in an aqueous medium, and has both heat-resistant storage stability and low-temperature fixability.

  As the resin fine particles, those produced by a known method such as an emulsion polymerization method, a soap-free emulsion polymerization method or a phase inversion emulsification method can be used. Among these production methods, the phase inversion emulsification method is particularly suitable because it does not require an emulsifier or a dispersion stabilizer and resin particles having a smaller particle diameter can be easily obtained.

  In the phase inversion emulsification method, a resin having self-dispersibility or a resin capable of developing self-dispersibility by neutralization is used. Here, the resin having self-water dispersibility is a resin containing a functional group capable of self-dispersion in an aqueous medium in the molecule, specifically, a carboxyl group, a sulfonic acid group, a phosphoric acid group, Or it is resin containing these salts. Further, a resin that can exhibit self-dispersibility by neutralization is a resin that contains a functional group in the molecule that can increase self-dispersibility in an aqueous medium by neutralization.

  By dissolving these resins in an organic solvent, adding a neutralizing agent as necessary, and mixing with an aqueous medium while stirring, the solution of the resin undergoes phase inversion emulsification to obtain fine particles. The organic solvent is removed using a method such as heating and decompression after phase inversion emulsification.

  Thus, according to the phase inversion emulsification method, a stable aqueous dispersion of resin fine particles can be obtained without substantially using an emulsifier or a dispersion stabilizer.

  The material of the resin is not particularly limited as long as it can be used as a binder resin for toner, and vinyl resin, polyester resin, epoxy resin, urethane resin, and the like can be used. Of these, polyester resins are preferred because they have sharp melt properties and therefore do not obstruct the low-temperature fixability of the core particles.

  Next, a method for forming the coating layer by attaching the resin fine particles to the surface of the core particles will be specifically described. First, an aqueous dispersion of resin fine particles is added to an aqueous dispersion of core particles, and the resin fine particles are adhered to the surface of the core particles. When the polarities of the core particles and the resin fine particles are greatly different, they can be attached by an electric suction force. Otherwise, it is necessary to control the dispersion state of the resin fine particles using an external means. . Specific methods include a method of adjusting the pH of the aqueous medium and a method of adding an inorganic salt in the aqueous medium. In either case, if the dispersion state of the resin fine particles is suddenly changed, the resin fine particles cause single aggregation and cannot be uniformly adhered to the core particles. Therefore, these operations are preferably performed gradually. .

  In addition, after the resin fine particles are attached, they are fixed or fused so that they do not easily peel off or fall off. As a specific method, there are a method in which heat treatment is performed in a state dispersed in an aqueous medium, and a method in which a solvent that dissolves or swells resin fine particles is added and absorbed to form a film, and then the solvent is removed. Moreover, the method of stirring and mixing the powder taken out by filtering and drying under heating can be mentioned. Among these methods, the method of heat treatment in an aqueous medium is preferable in that it can be fixed more uniformly and firmly and the operation is simple.

  At this time, the coating layer preferably has a coating amount of 1.0 to 10.0 parts by mass with respect to 100 parts by mass of the core particles. If the coating amount is within the above range, the core particles can be uniformly covered without exposing the core particles to the toner surface, so that sufficient charging performance can be obtained. In addition, a decrease in charge amount due to the influence of moisture in a high humidity environment can be prevented.

  When the coating layer contains an intrinsic element (for example, an S element derived from a sulfonic acid group), the coating amount is included in the toner using, for example, a fluorescent X-ray analyzer (XRF) described later. This element can be quantitatively analyzed and calculated.

  Further, the preferred particle diameter of the resin fine particles varies depending on the composition, but the volume-based median diameter (D50) is preferably 20 to 1000 nm. If it is less than 20 nm, depending on the composition of the resin fine particles, it may be buried and compatible with the core particles, and the function as a sufficient coating layer in the present invention may not be obtained. If it exceeds 1000 nm, the coating state between the toners may be biased.

  In the present invention, a known method can be used as a method for producing the core particle.

  For example, a binder resin, a colorant, and if necessary, a release agent are melt-kneaded, finely pulverized, and if necessary, a pulverization method obtained by a classification step, suspension polymerization method, dissolution suspension method, interface weight Examples include a method of producing in an aqueous medium such as a combination method, a dispersion polymerization method, and an emulsion aggregation method.

  Among the above production methods, a method of production in an aqueous medium is preferable from the viewpoint of forming a uniform coating layer. In particular, a suspension polymerization method is preferred in which a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, and a release agent is dispersed in an aqueous medium and the polymerizable monomer is polymerized.

  Specifically, first, at least a colorant and a release agent are added to the polymerizable monomer that is the main constituent material of the core particles, and a disperser such as a homogenizer, a ball mill, a colloid mill, or an ultrasonic disperser is used. A polymerizable monomer composition in which these are uniformly dissolved or dispersed is prepared. At this time, in the polymerizable monomer composition, a polyfunctional monomer, a chain transfer agent, a charge control agent, a plasticizer, and other additives (for example, a pigment dispersant, Release agent dispersant) can be added as appropriate.

  Next, the polymerizable monomer composition is put into an aqueous medium containing a dispersion stabilizer prepared in advance, and suspended using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser. Granulate.

  The polymerization initiator may be mixed with other additives when preparing the polymerizable monomer composition, or may be mixed into the polymerizable monomer composition just before being suspended in the aqueous medium. Good. Moreover, it can also be added in the state melt | dissolved in the polymerizable monomer and the solvent during granulation or after granulation completion, ie, just before starting a polymerization reaction.

  In the polymerization step, the suspension after granulation is heated to a temperature of 50 to 90 ° C., the particles of the polymerizable monomer composition in the suspension maintain the particle state, and the particles float and settle. To avoid this, it is carried out with stirring.

  The said polymerization initiator decomposes | disassembles easily by heating and produces | generates a free radical (radical). The generated radical is added to the unsaturated bond of the polymerizable monomer to newly generate an adduct radical. The generated adduct radical is further added to the unsaturated bond of the polymerizable monomer. By repeating such an addition reaction in a chain, the polymerization reaction proceeds, and core particles containing the polymerizable monomer as a main constituent material are formed.

  Distillation may be performed using a known method such as reduced pressure or elevated temperature after the second half of the polymerization reaction or after the completion of the polymerization reaction. By performing the distillation step, the remaining unreacted polymerizable monomer can be removed.

  Here, the following can be used as the polymerizable monomer.

  Styrene; α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert- Styrenes such as butyl styrene, pn-hexyl styrene, pn-octyl, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene Monomer: methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, acrylic acid 2-chloroethyl, phenyl acrylate, acrylic acid-2-hydro Acrylic esters such as ethyl; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Methacrylic acid esters such as stearyl, phenyl methacrylate, 2-hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, acrylamide.

  Among these polymerizable monomers, it is preferable to use a mixture of styrene or a styrene derivative and another polymerizable monomer from the viewpoint of developing characteristics and durability of the toner. The mixing ratio of these polymerizable monomers may be appropriately selected in consideration of the desired glass transition temperature of the core particles.

  The polymerization initiator is not particularly limited, and a known peroxide polymerization initiator or azo polymerization initiator can be used.

  Examples of peroxide polymerization initiators include the following. t-butyl peroxylaurate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, t- Butyl peroxyacetate, t-butyl peroxyisononanoate, t-butyl peroxybenzoate, t-amyl peroxyneodecanoate, t-amyl peroxypivalate, t-amyl peroxy-2-ethylhexano Ate, t-amyl peroxyacetate, t-amyl peroxyisononanoate, t-amyl peroxybenzoate, t-hexyl peroxyneodecanoate, t-hexyl peroxypivalate, t-hexyl peroxy-2 -Ethyl hexanoate, t-hexyl peroxybenzoe Α-cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate 1-cyclohexyl-1-methylethylperoxyneodecanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, 2,5-dimethyl-2,5-bis ( Peroxyester polymerization such as benzoylperoxy) hexane, t-butylperoxy-3,5,5-trimethylhexanoate, 2,5-dimethyl-2,5-bis (m-toluoylperoxy) hexane Initiator: di-n-propyl peroxydicarbonate, di-n-butyl peroxydicarbonate, di-n-pentylperoxydicarbonate Diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate, di (3-methoxybutyl) peroxydi Peroxydicarbonate-based polymerization initiators such as carbonate and di (4-t-butylcyclohexyl) peroxydicarbonate; diisobutyryl peroxide, diisononanoyl peroxide, di-n-octanoyl peroxide, dilauroylper Diacyl peroxide polymerization initiators such as oxide, distearoyl peroxide, dibenzoyl peroxide, di-m-toluoyl peroxide, benzoyl-m-toluoyl peroxide; t-hexyl peroxide Peroxymonocarbonate polymerization initiators such as pill monocarbonate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2-ethylhexyl monocarbonate, t-butylperoxyallyl monocarbonate; 1,1-di-t -Hexylperoxycyclohexane, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane, 2,2-di-t-butylper Peroxyketal polymerization initiators such as oxybutane; dialkyl peroxide polymerization initiators such as dicumyl peroxide, di-t-butyl peroxide, and t-butylcumyl peroxide.

  Examples of the azo polymerization initiator include the following. 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis -4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile.

  Among these polymerization initiators, peroxide-based polymerization initiators are preferable because there is little residue of decomposition products. In addition, two or more of these polymerization initiators can be used simultaneously as necessary. In this case, the preferred amount of the polymerization initiator used is 0.1 to 20.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  In the production of the core particles by the suspension polymerization method described above, a chain transfer agent can be used for the purpose of adjusting the molecular weight. Examples of the chain transfer agent include the following. n-pentyl mercaptan, isopentyl mercaptan, 2-methylbutyl mercaptan, n-hexyl mercaptan, n-heptyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, t-nonyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, alkyl mercaptans such as n-tetradecyl mercaptan, t-tetradecyl mercaptan, n-pentadecyl mercaptan, n-hexadecyl mercaptan, t-hexadecyl mercaptan, stearyl mercaptan; alkyl esters of thioglycolic acid; mercaptopropionic acid Alkyl esters; halogenated hydrocarbons such as chloroform, carbon tetrachloride, ethylene bromide, carbon tetrabromide; α-methylstyrene dimer.

  These chain transfer agents are not necessarily used, but a preferable addition amount when used is 0.05 to 3.00 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  In addition, in the production of the core particles by the suspension polymerization method described above, a small amount of a polyfunctional monomer can be used in combination for the purpose of improving high temperature offset resistance. The high temperature offset is a phenomenon in which a part of the toner melted at the time of fixing adheres to the surface of the above-described heat roller or fixing film, which contaminates the subsequent fixing sheet. As the polyfunctional monomer, compounds having two or more polymerizable double bonds are mainly used, and specific examples thereof include the following. Aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylate esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; divinylaniline, divinyl ether and divinyl Divinyl compounds such as sulfide and divinyl sulfone; compounds having three or more vinyl groups.

  These polyfunctional monomers are not necessarily used, but a preferable addition amount when used is 0.01 to 1.00 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Moreover, in this invention, you may superpose | polymerize by adding polar resin in the polymerizable monomer composition mentioned above.

  For example, examples of the polar resin include a polyester resin. When this polyester resin is dissolved in the polymerizable monomer composition and polymerized, the resin tends to move to the surface layer of the droplets in the aqueous medium, and is unevenly distributed on the surface of the particle as the polymerization proceeds. Therefore, the granulation property is improved, and the aforementioned release agent can be easily included.

  As said polyester resin, what polycondensated the polyhydric alcohol component and the polyhydric carboxylic acid component by the well-known method can be used. Examples of the polyhydric alcohol component and the polycarboxylic acid component include the divalent alcohol, the trivalent or higher alcohol, the divalent carboxylic acid, the trivalent or higher carboxylic acid, the monovalent carboxylic acid component, and the monovalent alcohol described above. Ingredients can be used. Moreover, said alcohol component may be used independently and may be used in a mixed state.

  The addition amount of the resin is preferably in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Further, a binder resin solution obtained by dissolving or dispersing at least a binder resin, a colorant, and a release agent in a solvent capable of dissolving the binder resin in an aqueous medium in which a dispersion stabilizer is dispersed. It is also preferable to produce the core particles through a step of suspending in a solvent and removing the solvent.

  Specifically, first, the binder resin that is the main constituent material of the core particles is dissolved in an organic solvent in which the binder resin is soluble, and at least a colorant is added to the homogenizer, ball mill, colloid mill, ultrasonic disperser. A mixture in which these are uniformly dissolved or dispersed is prepared using a dispersing machine such as

  At this time, a wax as a mold release agent, a charge control agent, and an additive such as a dispersant can be appropriately added to the mixture as necessary.

  Examples of the solvent that can be used as the organic solvent for dissolving the binder resin and the like include the following. Hydrocarbon solvents such as ethyl acetate, xylene and hexane, halogenated hydrocarbon solvents such as methylene chloride, chloroform and dichloroethane, ester solvents such as methyl acetate, ethyl acetate, butyl acetate and isopropyl acetate, ethers such as diethyl ether Solvents such as acetone, methyl ethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexane.

  Next, the mixture is put into an aqueous medium containing a dispersion stabilizer prepared in advance and suspended using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser. Form.

  There is no restriction | limiting in particular as a stirring apparatus which has a rotary blade, If it is a general thing as an emulsifier and a disperser, it can be used.

  For example, Ultra Turrax (manufactured by IKA), Polytron (manufactured by Kinematica), TK Auto Homo Mixer (manufactured by Special Mechanized Industry Co., Ltd.), Ebara Milder (manufactured by Ebara Corporation), TK Homomic Line Flow (Made by Special Machine Industries Co., Ltd.), colloid mill (made by Shinko Pantech Co., Ltd.), thrasher, trigonal wet pulverizer (made by Mitsui Miike Chemical Co., Ltd.), Cavitron (made by Eurotech), fine flow mill Examples thereof include a continuous type emulsifier such as (manufactured by Taiheiyo Kiko Co., Ltd.), a batch type continuous emulsifier such as Claremix (manufactured by M Technique Co., Ltd.), and fill mix (manufactured by Tokushu Kika Kogyo Co., Ltd.).

  As an aqueous medium used in the present invention, water alone may be used, but a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohols such as methanol, isopropanol and ethylene glycol, cellsolves such as dimethylformamide, tetrahydrofuran and methyl cellosolve, and lower ketones such as acetone and methyl ethyl ketone. It is also a preferable production method that an appropriate amount of the organic solvent used as the mixture is mixed in the aqueous medium used in the present invention. This is considered to have the effect of enhancing the droplet stability during granulation and facilitating the suspension of the aqueous medium and the mixture.

  In order to remove the organic solvent from the dissolved resin droplets thus obtained, it is possible to gradually raise the temperature of the entire system and employ a method of evaporating and removing the organic solvent in the dissolved resin droplets. it can. The organic solvent is removed from the dissolved resin droplets as described above to form an aqueous dispersion of core particles.

  In the production of the core particles by the dissolution suspension method described above, various resins conventionally known as binder resins for electrophotography are used as the binder resin. Among them, (a) a polyester resin, (b) a hybrid resin having a polyester unit and a vinyl copolymer unit, (c) a mixture of the hybrid resin and the vinyl copolymer, (d) a hybrid resin and a polyester. A mixture of a resin, (e) a mixture of a polyester resin and a vinyl copolymer, and (f) a polyester resin, a hybrid resin having a polyester unit and a vinyl copolymer unit, a vinyl copolymer, and It is preferable that a resin selected from the group consisting of

  Specifically, the following compounds can be used as the alcohol and carboxylic acid that can be used in obtaining the polyester resin or the polyester unit.

Examples of the divalent alcohol include the following. Ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1, 5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, neopentyl glycol, 2,2,4-trimethylpentane-1,3-diol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, a bisphenol derivative represented by the following general formula (I), or a diol represented by the following formula (II).
Formula (I)

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10.)
Formula (II)

(In the formula, R ′ represents —CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) —, or —CH ₂ —C (CH ₃ ) ₂ —).

  Examples of trihydric or higher alcohols include the following. Sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene.

  Examples of the divalent carboxylic acid include the following. Dicarboxylic acids such as naphthalenedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid; phthalic anhydride, maleic anhydride, etc. Dicarboxylic acid anhydrides; lower alkyl esters of dicarboxylic acids such as dimethyl terephthalate, dimethyl maleate and dimethyl adipate.

  Moreover, you may make it bridge | crosslink by using trivalent or more carboxylic acid. The following are mentioned as carboxylic acid more than trivalence. Trimellitic acid, tri n-ethyl 1,2,4-tricarboxylate, tri n-butyl 1,2,4-tricarboxylate, tri n-hexyl 1,2,4-tricarboxylate, 1,2,4-benzene Triisobutyl tricarboxylate, tri n-octyl 1,2,4-benzenetricarboxylate, tri-2-ethylhexyl 1,2,4-benzenetricarboxylate, and lower alkyl esters of tricarboxylic acid.

  Moreover, you may use a monovalent | monohydric carboxylic acid component and a monovalent alcohol component to such an extent that the characteristic of a polyester resin is not impaired. Examples of the monovalent carboxylic acid component include the following. Benzoic acid, naphthalenecarboxylic acid, salicylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, phenoxyacetic acid, biphenylcarboxylic acid, acetic acid, propionic acid, butyric acid, octanoic acid, decanoic acid, dodecanoic acid, stearic acid. Examples of the monovalent alcohol component include the following. n-butanol, isobutanol, sec-butanol, n-hexanol, n-octanol, lauryl alcohol, 2-ethylhexanol, decanol, cyclohexanol, benzyl alcohol, dodecyl alcohol.

  Examples of the method for producing the polyester include an oxidation reaction synthesis method, synthesis from a carboxylic acid and a derivative thereof, an ester group introduction reaction typified by a reaction with Michael, and a dehydration condensation reaction from a carboxylic acid compound and an alcohol compound. Examples of the method used include a reaction from an acid halide and an alcohol compound, and a transesterification reaction. The catalyst may be a general acidic or alkaline catalyst used in the esterification reaction, such as zinc acetate or a titanium compound. Thereafter, it may be highly purified by a production method such as a recrystallization method or a distillation method.

  In the production of the core particles, a known surfactant, organic dispersant, or inorganic dispersant can be used as a dispersion stabilizer added to the aqueous medium. Among these, inorganic dispersants can be suitably used because they are less likely to produce ultrafine powder, are less likely to lose stability even when the polymerization temperature is changed, and are easy to wash. Examples of such inorganic dispersants include the following. Polyvalent metal phosphates such as tricalcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; inorganic salts such as calcium metasuccinate, calcium sulfate and barium sulfate; Inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite and alumina.

  When these inorganic dispersants are used, they may be used as they are in an aqueous medium, but in order to obtain finer particles, they are prepared and used in an aqueous medium using a compound capable of generating inorganic dispersant particles. You can also. For example, in the case of tricalcium phosphate, sodium phosphate aqueous solution and calcium chloride aqueous solution can be mixed under high-speed stirring to produce water-insoluble tricalcium phosphate, which enables more uniform and fine dispersion. Become. These inorganic dispersants can be almost completely removed by adding an acid or an alkali after the polymerization and dissolving.

  In the case of suspension polymerization, these inorganic dispersants are preferably used alone in an amount of 0.2 to 20.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer. Moreover, you may use together 0.001 thru | or 0.100 mass part surfactant with respect to 100 mass parts of polymerizable monomers as needed. In the case of the dissolution suspension method, it is preferable to use an amount in the above range with respect to 100 parts by mass of the binder resin. Examples of the surfactant include the following. Sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate.

  Known colorants can be used as the colorant used in the toner of the present invention.

  As the black colorant, carbon black and magnetic powder can be used, and the yellow / magenta / cyan colorant shown below may be used to adjust the color to black.

  Examples of the yellow colorant include the following. Condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168, 180 are preferably used.

  Examples of the magenta colorant include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254 are preferably used.

  Examples of the cyan colorant include the following. Copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 are preferably used.

  These colorants can be used alone or in combination, and further in the form of a solid solution. When magnetic powder is used as the black colorant, the amount added is preferably 40 to 150 parts by mass with respect to 100 parts by mass of the binder resin. When carbon black is used as the black colorant, the amount added is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin. In the case of a color toner, it is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in the toner, and the preferred addition amount is 1 with respect to 100 parts by mass of the binder resin. Thru | or 20 mass parts.

  These colorants need to pay attention to polymerization inhibition and aqueous phase migration, and are preferably subjected to surface modification such as a hydrophobization treatment as necessary. For example, a preferable method for surface-treating a dye-based colorant includes a method in which a polymerizable monomer is polymerized in the presence of a dye in advance, and the obtained colored polymer is added to the monomer composition. . For carbon black, in addition to the same treatment as the above dye, a grafting treatment may be performed with a substance that reacts with the surface functional group of carbon black, for example, polyorganosiloxane.

  The magnetic powder is mainly composed of iron oxides such as triiron tetroxide and γ-iron oxide, and generally has hydrophilicity, so that toner particles are produced in an aqueous medium. The magnetic powder tends to be unevenly distributed on the particle surface due to the interaction with water as a dispersion medium. Therefore, the toner particles obtained are inferior in fluidity and uniformity of triboelectric charge due to the magnetic powder exposed on the surface. Therefore, the surface of the magnetic powder is preferably subjected to a hydrophobic treatment uniformly with a coupling agent. Examples of the coupling agent that can be used include a silane coupling agent and a titanium coupling agent, and a silane coupling agent is particularly preferably used.

  Examples of those that can be used for the release agent used in the present invention include the following. Petroleum wax such as paraffin wax, microcrystalline wax, petrolatum and derivatives thereof; montan wax and derivatives thereof; hydrocarbon wax and derivatives thereof according to Fischer-Tropsch method; polyolefin wax and derivatives thereof represented by polyethylene; carnauba wax and candelilla Natural waxes such as waxes and derivatives thereof. Derivatives include block copolymers with oxides and vinyl monomers, and graft modified products. Furthermore, higher fatty alcohols, fatty acids such as stearic acid and palmitic acid, or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant-based waxes and animal waxes can also be used.

  The toner of the present invention can contain a charge control agent as necessary for the purpose of stabilizing the charge characteristics. As a method of inclusion, there are a method of adding to the inside of toner particles and a method of adding externally. As the charge control agent, a known one can be used, but when added inside, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable. Specific examples of the negative charge control agent include the following compounds. Metallic compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid, etc .; metal salts or metal complexes of azo dyes or azo pigments; polymeric compounds having a carboxylic acid group in the side chain; boron Compound, urea compound, silicon compound, calixarene. Examples of positive charge control agents include quaternary ammonium salts, polymer compounds having quaternary ammonium salts in the side chain, guanidine compounds, nigrosine compounds, and imidazole compounds.

  The amount of these charge control agents used is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and the dispersion method. Therefore, although not uniquely limited, when added internally, it is preferably 0.1 to 10.0 parts by mass, more preferably 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin. Used in the range of parts by mass. In the case of external addition, the amount is preferably 0.005 to 1.000 parts by mass, more preferably 0.01 to 0.30 parts by mass with respect to 100 parts by mass of the toner particles.

  In the toner of the present invention, it is preferable that a fluidity improver is externally added to improve the image quality. As the fluidity improver, inorganic fine powders such as silicate fine powder, titanium oxide, and aluminum oxide are preferably used. These inorganic fine powders are preferably hydrophobized with a hydrophobizing agent such as a silane coupling agent, silicone oil or a mixture thereof.

  The toner of the present invention can be used as it is as a one-component developer or as a two-component developer by mixing with a magnetic carrier. When used as a two-component developer, the average particle size of the carrier to be mixed is preferably 10 to 100 μm, and the toner concentration in the two-component developer is preferably 2 to 15% by mass.

(Method for measuring the amount of sulfur element in the coating layer of toner particles and resin fine particles)
The amount of sulfur element in the coating layer can be determined by quantitative analysis of sulfur element contained in toner particles and resin fine particles using a fluorescent X-ray analyzer (XRF). The measurement method conforms to JIS K 0119-1969, and is specifically as follows.

  As a measuring device, wavelength dispersion type X-ray fluorescence analyzer “Axios” (manufactured by PANalytical) and attached dedicated software “SuperQ ver. 4.0F” (manufactured by PANalytical) for setting measurement conditions and analyzing measurement data ) Is used. Rh is used as the anode of the X-ray tube, the measurement atmosphere is vacuum, the measurement diameter (collimator mask diameter) is 27 mm, and the measurement time is 10 seconds. Further, when measuring a light element, it is detected by a proportional counter (PC), and when measuring a heavy element, it is detected by a scintillation counter (SC).

  As a measurement sample, about 4 g of toner particles or resin fine particles are used. The measurement sample is put in a special aluminum ring for press and flattened, and pressed using a tablet molding compressor “BRE-32” (manufactured by Maekawa Test Instruments Co., Ltd.) at 20 MPa for 60 seconds to obtain a thickness. Pellets molded to about 2 mm and a diameter of about 39 mm are used.

  Measurement is performed under the above conditions, the element is identified based on the obtained X-ray peak position, and the concentration (mass%) is calculated from the count rate (unit: cps) which is the number of X-ray photons per unit time. calculate.

  In addition, when a compound containing a sulfur element (for example, a charge control agent containing a sulfur element) is used in producing the core particle, the core particle may contain the sulfur element. In this case, the amount of sulfur element contained in the coating layer is obtained by subtracting the amount of sulfur element present in the core particle from the amount of sulfur element obtained by the above measurement method using toner particles as a measurement sample. The amount of sulfur element in the core particles can be measured by a separately known method, or may be determined from the amount of the material containing sulfur element at the time of core particle production.

(Measurement of coating amount of resin fine particles)
In accordance with the above-described method for measuring the amount of sulfur, the amount of sulfur element S1 (mass%) contained in the resin fine particles and the amount of sulfur element S2 (mass%) contained in the toner particles are calculated. The obtained result is substituted into the following formula to calculate the coating amount (% by mass).
Covering amount (mass%) = 100 / ((S1 / S2) -1)

(Measurement of acid value)
The acid value is represented by the amount of potassium hydroxide necessary to neutralize the carboxyl group and sulfonic acid group contained in 1 g of the resin, and is measured according to JIS K 0070-1992. Specifically, Measure according to the following procedure.

(1) Preparation of Reagent 1.0 g of phenolphthalein is dissolved in 90 ml of ethyl alcohol (95 vol%), and ion exchanged water is added to make 100 ml to obtain a phenolphthalein solution.

  7 g of special grade potassium hydroxide is dissolved in 5 ml of water, and ethyl alcohol (95 vol%) is added to make 1.0 l. In order not to touch carbon dioxide, etc., put in an alkali-resistant container and let stand for 3 days, then filter to obtain a potassium hydroxide solution. The obtained potassium hydroxide solution is stored in an alkali-resistant container. The factor of the potassium hydroxide solution was as follows: 25 ml of 0.1 mol / l hydrochloric acid was placed in an Erlenmeyer flask, a few drops of the phenolphthalein solution were added, titrated with the potassium hydroxide solution, and the hydroxide required for neutralization. Determined from the amount of potassium solution. As the 0.1 mol / l hydrochloric acid, one prepared according to JIS K 8001-1998 is used.

(2) Operation (A) Main test 2.0 g of a sample is precisely weighed into a 200 ml Erlenmeyer flask, 100 ml of a mixed solution of toluene / ethanol (2: 1) is added and dissolved over 5 hours. Subsequently, several drops of the phenolphthalein solution is added as an indicator, and titration is performed using the potassium hydroxide solution. The end point of titration is when the light red color of the indicator lasts for about 30 seconds.
(B) Blank test Titration is performed in the same manner as above except that no sample is used (that is, only a mixed solution of toluene / ethanol (2: 1) is used).

(3) The acid value is calculated by substituting the obtained result into the following formula.
A = [(C−B) × f × 5.61] / S
Here, A: acid value (mgKOH / g), B: addition amount (ml) of a potassium hydroxide solution in a blank test, C: addition amount (ml) of a potassium hydroxide solution in this test, f: potassium hydroxide Solution factor, S: sample (g).

(Measurement of glass transition temperature)
The glass transition temperature is measured in accordance with ASTM D3418-82 using a differential scanning calorimeter “Q1000” (manufactured by TA Instruments).
The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium.

  First, about 5 mg of a sample is precisely weighed in an aluminum pan, and an empty aluminum pan is prepared as a reference pan. In a nitrogen atmosphere, the measurement temperature range is 20 to 140 ° C., the temperature rising rate is 2 ° C./min, and the modulation amplitude is ± 0. Measurement is performed under the conditions of 6 ° C. and a frequency of once / minute.

  From the reversing heat flow curve at the time of temperature rise obtained by measurement, draw a tangent line between the endothermic curve and the front and back baselines, find the midpoint of the straight line connecting the intersections of each tangent line, and this is the glass transition Let it be temperature.

(Measurement of weight average particle diameter (D4) and number average particle diameter (D1) of core particles and toner)
The weight average particle diameter (D4) and number average particle diameter (D1) of the core particles and toner are calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting of measurement conditions and analysis of measurement data, attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. The measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software was set as follows.

  On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . Measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) and the number average particle diameter (D1) are calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set in the dedicated software is the weight average particle diameter (D4). The “average diameter” in the “analysis / number statistics (arithmetic average)” screen when the graph / number% is set in the dedicated software is the number average particle diameter (D1).

(Measurement of median diameter (D50) of resin fine particles)
The median diameter (D50) of the resin fine particles was measured using a laser diffraction / scattering particle size distribution measuring apparatus.

Specifically, it is measured according to JIS Z8825-1 (2001).
As a measuring device, a laser diffraction / scattering particle size distribution measuring device “LA-920” (manufactured by Horiba, Ltd.) is used. The dedicated software “HORIBA LA-920 for Windows (registered trademark) WET (LA-920) Ver. 2.02” attached to LA-920 is used for setting measurement conditions and analyzing measurement data. In addition, as a measurement medium, ion-exchanged water from which impure solids are removed in advance is used.

The measurement procedure is as follows.
(1) A batch type cell holder is attached to LA-920.
(2) A predetermined amount of ion-exchanged water is put into a batch type cell, and the batch type cell is set in a batch type cell holder.
(3) The inside of the batch cell is stirred using a dedicated stirrer chip.
(4) Press the “refractive index” button on the “display condition setting” screen and set the relative refractive index to 1.20.
(5) In the “display condition setting” screen, the particle size standard is set as the volume standard.
(6) After performing warm-up operation for 1 hour or more, optical axis adjustment, optical axis fine adjustment, and blank measurement are performed.
(7) About 3 ml of the resin fine particle dispersion prepared in the synthesis example is placed in a glass 100 ml flat bottom beaker. Further, about 57 ml of ion exchange water is added to dilute the resin fine particle dispersion. Among them, as a dispersant, “Contaminone N” (a nonionic surfactant, an anionic surfactant, a 10% by weight aqueous solution of a neutral detergent for washing a pH 7 precision measuring instrument comprising an organic builder, Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting the product (manufactured) with ion exchange water about 3 times by mass is added.
(8) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
(9) The beaker of (7) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the aqueous solution in a beaker may become the maximum.
(10) Continue ultrasonic dispersion for 60 seconds. Moreover, in ultrasonic dispersion, it adjusts suitably so that the water temperature of a water tank may become 10 to 40 degreeC.
(11) The resin fine particle dispersion liquid subjected to the ultrasonic treatment in (10) is immediately added little by little to a batch type cell while taking care not to enter bubbles, and the transmittance of the tungsten lamp is 90% to 95%. Adjust to be%. Then, the particle size distribution is measured. The volume-based median diameter (D50) is calculated based on the obtained volume-based particle size distribution data.

Hereinafter, the production method of the present invention will be specifically described with reference to examples. Examples 6, 7 and 10-13 are reference examples.

<Preparation Example of Resin Fine Particle Dispersion 1: Resin Fine Particle Dispersion (a)>
(Synthesis of polyester resin)
The following monomers were charged into a reaction vessel equipped with a stirrer, condenser, thermometer and nitrogen introduction tube, 0.03 parts by mass of tetrabutoxy titanate was added as an esterification catalyst, and the temperature was raised to 220 ° C. in a nitrogen atmosphere. Warmed and reacted for 5 hours with stirring.
Bisphenol A-propylene oxide 2 mol adduct: 49.2 parts by mass Ethylene glycol: 8.9 parts by mass Terephthalic acid: 21.7 parts by mass Isophthalic acid: 12.4 parts by mass 5-sodium sulfoisophthalic acid: 4.8 parts by mass Subsequently, 3.0 parts by mass of trimellitic anhydride was added, and the reaction was further carried out for 5 hours while reducing the pressure in the reaction vessel to 5 to 20 mmHg to obtain a polyester resin.

(Preparation of resin fine particle dispersion)
A reaction vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube was charged with 100.0 parts by mass of the obtained polyester resin, 45.0 parts by mass of methyl ethyl ketone, and 45.0 parts by mass of tetrahydrofuran, and heated to a temperature of 80 ° C. And dissolved.

  Next, under stirring, 300.0 parts by mass of ion-exchanged water having a temperature of 80 ° C. was added to the reaction vessel and dispersed in water, and then the resulting aqueous dispersion was transferred to a distillation apparatus so that the fraction temperature was 100 ° C. Distillation was performed until reached.

  After cooling, ion-exchanged water was added to the obtained aqueous dispersion to adjust the resin concentration in the dispersion to 20%. This was designated as resin fine particle dispersion (a). About the obtained dispersion liquid (a), the acid value of the resin dispersed in the dispersion liquid, the acid value derived from the sulfonic acid, the acid value derived from the carboxyl group, and the glass transition temperature were measured by the methods described above. Furthermore, the median diameter (D50) of the fine particles was measured by the method described above.

<Preparation Examples 2 to 17 of Resin Fine Particle Dispersion>
In Preparation Example 1, the reaction was carried out in the same manner as in Preparation Example 1 except that the amount of monomer charged was changed as shown in Table 1, to obtain an aqueous dispersion of a polyester resin. This was designated as resin fine particle dispersions (b) to (q). Regarding the obtained resin fine particle dispersions (b) to (q), the acid value of the resin dispersed in each dispersion, the acid value derived from the sulfonic acid, the acid value derived from the carboxyl group, and the glass transition temperature are described above. It measured by the method of. Furthermore, the median diameter (D50) of the fine particles of each dispersion was measured by the method described above.
The results are summarized in Table 2.

<Production Example of Core Particle Dispersion 1: Core Particle Dispersion (A)>
(Preparation of pigment dispersion paste)
Styrene: 219.5 parts by mass Cu phthalocyanine (Pigment Blue 15: 3): 19.7 parts by mass After sufficiently premixing the above materials in a container, an attritor (manufactured by Mitsui Miike Chemical Co., Ltd.) is maintained at a temperature of 20 ° C. or less. ) Was dispersed and mixed for about 4 hours to prepare a pigment dispersion paste.

(Preparation of core particle dispersion)
Into 1152.0 parts by mass of ion-exchanged water, 390.0 parts by mass of a 0.1 mol / liter-Na ₃ PO ₄ aqueous solution was added, and the temperature was adjusted to 60 ° C. while stirring using CLEARMIX (M Technique). Warmed up. Thereafter, 58.0 parts by mass of 1.0 mol / liter-CaCl ₂ aqueous solution was added and stirring was continued to prepare an aqueous medium containing a dispersion stabilizer composed of Ca ₃ (PO ₄ ) ₂ .

On the other hand, the following materials were added to the pigment dispersion paste and dispersed and mixed using an attritor (manufactured by Mitsui Miike Chemical Industries) to prepare a polymerizable monomer composition.
n-butyl acrylate: 108.1 parts by mass Amorphous polyester: 15.1 parts by mass (Polycondensation product of propylene oxide-modified bisphenol A and isophthalic acid, glass transition temperature Tg = 58 ° C., Mw = 7800, acid value = 13mgKOH / g)
Aluminum salicylate compound: 3.1 parts by mass (Bontron E-88: manufactured by Orient Chemical Co., Ltd.)
Divinylbenzene: 0.049 parts by mass The polymerizable monomer composition is heated to 60 ° C., and ester wax (main component C ₁₉ H ₂₉ COOC ₂₀ H ₄₁ , mp = 68.6 ° C.) is added thereto. 32.8 parts by mass were added and mixed and dissolved.

  Next, 7.8 parts by mass of 2,2'-azobis (2,4-dimethylvaleronitrile) was further added and dissolved as a polymerization initiator.

  This was put into the aqueous medium, and granulated by stirring for 10 minutes at 10,000 rpm in a nitrogen atmosphere at a temperature of 60 ° C. using CLEARMIX (M Technique Co., Ltd.).

  Furthermore, the obtained suspension was polymerized at a temperature of 60 ° C. for 10 hours while stirring with a paddle stirring blade.

  After the completion of the polymerization, the obtained dispersion of polymer particles was cooled, and ion exchange water was added to adjust the concentration of polymer particles in the dispersion to 20%. This was designated as core particle dispersion (A).

  A part of the dispersion was extracted and diluted hydrochloric acid was added until the pH reached 1.5 to dissolve and remove the dispersion stabilizer. Thereafter, when the glass transition temperature and the weight average particle diameter (D4) of the powder particles obtained by filtration, washing and drying were measured, the glass transition temperature was 45 ° C. and the weight average particle diameter (D4) was 6.4 μm. there were.

<Production Example 2 of Core Particle Dispersion: Core Particle Dispersion (B)>
The core particle dispersion liquid was the same as in Production Example 1 of the core particle dispersion liquid, except that 219.5 parts by mass of styrene was changed to 170.4 parts by mass, and 108.1 parts by mass of n-butyl acrylate was changed to 157.2 parts by mass. In the same manner as in Production Example 1, a core particle dispersion (B) was produced.

  A part of the dispersion was extracted and diluted hydrochloric acid was added until the pH reached 1.5 to dissolve and remove the dispersion stabilizer. Thereafter, when the glass transition temperature and the weight average particle diameter (D4) of the powder particles obtained by filtration, washing and drying were measured, the glass transition temperature was 25 ° C. and the weight average particle diameter (D4) was 6.6 μm. there were.

<Production Example 3 of Core Particle Dispersion: Core Particle Dispersion (C)>
The core particle dispersion liquid was the same as in Production Example 1 of the core particle dispersion liquid, except that 219.5 parts by mass of styrene was changed to 271.9 parts by mass, and 108.1 parts by mass of n-butyl acrylate was changed to 55.7 parts by mass. In the same manner as in Production Example 1, a core particle dispersion (C) was produced.

  A part of the dispersion was extracted and diluted hydrochloric acid was added until the pH reached 1.5 to dissolve and remove the dispersion stabilizer. Thereafter, when the glass transition temperature and the weight average particle diameter (D4) of the powder particles obtained by filtration, washing and drying were measured, the glass transition temperature was 58 ° C. and the weight average particle diameter (D4) was 6.4 μm. there were.

<Production Example 4 of Core Particle Dispersion: Core Particle Dispersion (D)>
The core particle dispersion liquid was the same as in Production Example 1 of the core particle dispersion liquid, except that 219.5 parts by mass of styrene was changed to 163.8 parts by mass, and 108.1 parts by mass of n-butyl acrylate was changed to 163.8 parts by mass. In the same manner as in Production Example 1, a core particle dispersion (D) was produced.

  A part of the dispersion was extracted and diluted hydrochloric acid was added until the pH reached 1.5 to dissolve and remove the dispersion stabilizer. Thereafter, when the glass transition temperature and the weight average particle diameter (D4) of the powder particles obtained by filtration, washing and drying were measured, the glass transition temperature was 18 ° C. and the weight average particle diameter (D4) was 6.5 μm. there were.

<Manufacturing Example 5 of Core Particle Dispersion: Core Particle Dispersion (E)>
The core particle dispersion liquid was the same as in Production Example 1 of the core particle dispersion liquid, except that 219.5 parts by mass of styrene was changed to 285.0 parts by mass, and 108.1 parts by mass of n-butyl acrylate was changed to 42.6 parts by mass. In the same manner as in Production Example 1, a core particle dispersion (E) was produced.

  A part of the dispersion was extracted and diluted hydrochloric acid was added until the pH reached 1.5 to dissolve and remove the dispersion stabilizer. Thereafter, when the glass transition temperature and the weight average particle diameter (D4) of the powder particles obtained by filtration, washing and drying were measured, the glass transition temperature was 61 ° C. and the weight average particle diameter (D4) was 6.5 μm. there were.

<Production Example 6 of Core Particle Dispersion: Core Particle Dispersion (F)>
(Preparation of binder resin solution)
The following materials were charged into a reaction vessel equipped with a cooling tube, a nitrogen introducing tube and a stirrer.
1,3-propanediol: 847 parts by mass dimethyl terephthalate: 861 parts by mass 1,6-hexanedioic acid: 212 parts by mass tetrabutoxy titanate (condensation catalyst): 3 parts by mass Methanol produced at 170 ° C. under a nitrogen stream It was made to react for 7 hours, distilling off. Next, while gradually raising the temperature to 240 ° C., the reaction was performed for 5 hours while distilling off the produced propylene glycol and water in a nitrogen stream, and the reaction was further carried out under a reduced pressure of 20 mmHg, followed by removal. The taken-out resin was cooled to room temperature and then pulverized and granulated to obtain a binder resin 1. The Tg of binder resin 1 was 46 ° C.
Next, 50 parts by mass of ethyl acetate is put into a hermetic container equipped with stirring blades, and 50 parts by mass of the binder resin 1 is added to the part stirred at 100 rpm, and the mixture is stirred at room temperature for 3 days. A landing resin solution was prepared.

(Preparation of release agent dispersion)
Carnauba wax (melting point 83 ° C.): 18 parts by mass ethyl acetate: 82 parts by mass The above materials were put into a container with a stirring blade, and the system was heated to 70 ° C. to dissolve carnauba wax in ethyl acetate. .

  Next, the system was gradually cooled while gently stirring at 100 rpm, and cooled to 30 ° C. over 2 hours to obtain a milky white liquid.

  This solution was put into a heat-resistant container together with 20 parts by mass of 1 mm glass beads, dispersed for 3 hours with a paint shaker, glass beads were removed with a nylon mesh, and a release agent dispersion was obtained.

(Preparation of colorant dispersion)
Binder resin 1: 20 parts by mass Cu phthalocyanine (Pigment Blue 15: 3): 20 parts by mass Ethyl acetate: 60 parts by mass After sufficiently premixing the above materials in a container, the attritor ( The mixture was dispersed and mixed for about 4 hours using Mitsui Miike Kako) to obtain a colorant dispersion.

(Preparation of core particle dispersion)
-Preparation of oil phase Wax dispersion: 50 parts by mass (Carnauba WAX solid content: 18%)
Colorant dispersion: 25 parts by mass (pigment solid content: 20%, resin solid content: 20%)
Binder resin solution: 160 parts by mass (resin solid content: 50%)
Ethyl acetate: 15 parts by mass The above solution was put into a container, and an oil phase was prepared by stirring and dispersing for 5 minutes at 2000 rpm with a homodisper (manufactured by Tokushu Kika Kogyo Co., Ltd.).
-Preparation of aqueous phase Into 1152.0 parts by mass of ion-exchanged water, 390.0 parts by mass of a 0.1 mol / liter-sodium phosphate (Na ₃ PO ₄ ) aqueous solution was added, and Claremix (M Technique Co., Ltd.) was added. The mixture was heated to 60 ° C. with stirring. Thereafter, 58.0 parts by mass of 1.0 mol / liter-calcium chloride (CaCl ₂ ) aqueous solution was added and stirring was continued to produce a dispersion stabilizer composed of tricalcium phosphate (Ca ₃ (PO ₄ ) ₂ ). Further, 100 parts by mass of ethyl acetate was added to prepare an aqueous medium.
Emulsification and solvent removal The oil phase is put into the aqueous phase and granulated by stirring for 1 minute at 10,000 rpm in a nitrogen atmosphere at 60 ° C. using CLEARMIX (M Technique). Went.

  Further, the resulting suspension was stirred with a paddle stirring blade at a rotation speed of 150 rotations / minute, and the solvent was removed at 60 ° C. and reduced pressure to 500 mgHg for 5 hours to disperse the core particles. A liquid was obtained.

The obtained dispersion of core particles was cooled, and the supernatant was removed to adjust the concentration of core particles in the dispersion to 20%. This was designated as core particle dispersion (F).
A portion of the dispersion was extracted, diluted hydrochloric acid was added until the pH was 1.5, and the glass transition temperature and the weight average particle diameter (D4) of the powder particles obtained by washing with water and drying were measured. The glass transition temperature was 45 ° C. and the weight average particle size (D4) was 6.3 μm.

<Example 1>
(Preparation of toner particles 1)
The resin particle dispersion (a) 25.0 parts by mass (solids 5.0 parts by mass) is gently added to 500.0 parts by mass (solids 100.0 parts by mass) of the core particle dispersion (A). Added.

  Next, while raising the temperature of the oil bath for heating and maintaining the temperature at 55 ° C., 1 mol / l hydrochloric acid was added dropwise while taking care that the pH of the dispersion gradually changes, and the pH of the dispersion was adjusted to 1 Then, stirring was continued for 2 hours. Thereafter, a 1 mol / l aqueous sodium hydroxide solution was added dropwise with stirring until the pH of the dispersion reached 7.2.

  This dispersion was maintained at 65 ° C., which is higher than the glass transition temperature of the resin fine particles, and further stirred for 1 hour. After cooling the dispersion to 20 ° C., dilute hydrochloric acid was added until the pH reached 1.5. Further, after sufficiently washing with ion-exchanged water, it was filtered, dried and classified to obtain toner particles 1.

(Preparation of Toner 1)
100 parts by mass of untreated silica fine powder is treated with 10 parts by mass of hexamethyldisilazane, and further treated with 10 parts by mass of silicone oil to give a hydrophobic particle having a primary particle size of 12 nm and a BET specific surface area of 120 m ² / g. Silica fine powder was prepared. Next, 1.0 part by mass of the hydrophobic silica fine powder was added to 100.0 parts by mass of the toner particles, and mixed using a Henschel mixer (manufactured by Mitsui Miike Chemical Industries). Thus, toner 1 was produced.

<Examples 2 to 13 and Comparative Examples 1 to 6>
In Example 1, toner particles 1 to 19 were used in the same manner as in Example 1 except that the core particle dispersion, the resin fine particle dispersion, and the heat treatment temperature after adjusting to pH 7.2 were changed as shown in Table 3. In addition, toners 1 to 19 were obtained.

<Comparative Example 7>
(Preparation of toner particles 20)
A part of the resin fine particle dispersion (g) was taken out, dried at room temperature for a whole day and night, and further dried under a reduced pressure at 40 ° C. for a whole day and night to obtain a resin constituting the resin fine particle dispersion (g).

  In Production Example 1 of the core particle dispersion, 219.5 parts by mass of styrene was changed to 235.9 parts by mass, and 108.1 parts by mass of n-butyl acrylate was changed to 91.7 parts by mass. Further, 28.4 parts by mass of the resin constituting the resin fine particles (g) was dissolved in the polymerizable monomer composition. Otherwise, polymerization was carried out in the same manner as in Production Example 1 of the core particle dispersion, diluted hydrochloric acid was added, filtered, washed with water and dried to prepare toner particles 20.

(Production of Toner 20)
100 parts by mass of untreated silica fine powder is treated with 10 parts by mass of hexamethyldisilazane, and further treated with 10 parts by mass of silicone oil to give a hydrophobic particle having a primary particle size of 12 nm and a BET specific surface area of 120 m ² / g. Silica fine powder was prepared. Next, 1.0 part by mass of the hydrophobic silica fine powder was added to 100.0 parts by mass of the toner particles, and mixed using a Henschel mixer (manufactured by Mitsui Miike Chemical Industries). Thus, toner 20 was produced.

  The amount of sulfur contained in the coating layer of each toner particle, the coating amount of resin fine particles, and the weight average particle size were measured by the above-described methods. The results are summarized in Table 4.

<Evaluation of triboelectric chargeability of toner>
Each toner described above and a magnetic fine particle dispersed resin carrier whose surface was coated with a silicone resin were mixed so that the toner concentration was 4.0% by mass to obtain a two-component developer.

  Weigh 50 g of each two-component developer, leave it for 7 days at high temperature and high humidity (30 ° C / 80%), and then leave it for another 3 days at room temperature and normal humidity (23 ° C / 50%). The charge was reset. Using these two-component developers, image output was evaluated with a color copier CLC5500 remodeled machine (manufactured by Canon). Each toner is charged into the developing unit and an A4 image is output with an image area ratio of 25% without preliminary rotation.

(Evaluation of fogging on white background)
Next, the above developing machine output 50 sheets of solid white A4 images without preliminary rotation, and the fog evaluation of the white background portion was performed according to the following procedure to evaluate the toner triboelectric chargeability.

The reflectance of the solid white portion of the image was measured. Further, the reflectance of unused paper was measured. Then, the reflectance value of the solid white portion was subtracted from the reflectance value of the unused paper to obtain the fog density. The reflectance was measured with TC-6DS (manufactured by Tokyo Denshoku).
A: The fog density is less than 1.0% within 10 sheets (the frictional charging property is particularly excellent).
B: The fog density is less than 1.0% within 11 to 15 sheets (excellent triboelectric chargeability).
C: The fog density is less than 1.0% within 16 to 20 sheets (the frictional charging property is good).
D: The fog density is less than 1.0% within 21 to 30 sheets (the frictional charging property is slightly inferior).
E: The fog density is 1.0% or more in 31 sheets (friction chargeability is inferior)

<Environmental stability evaluation of toner chargeability>
First, weigh 50 g of a two-component developer and leave it for one day in an environment of room temperature and low humidity (23 ° C./5%), then put each in a 50 cc plastic container and shake it 200 times over 1 minute. .

  Next, the charge amount was measured using the method described above, and the obtained charge amount was defined as a charge amount L (mC / kg).

  Further, 50 g of the developer was weighed and left for one day in a high temperature and high humidity environment (30 ° C./80%), and then placed in a 50 cc plastic container and shaken 200 times over 1 minute. The charge amount measured by the above method was defined as a charge amount H (μC / g).

From the obtained charge amount L (mC / kg) and charge amount H (mC / kg), charge retention rate (%) = 100 × charge amount H (mC / kg) / charge amount L (mC / kg)
The charge retention rate (%) in a high humidity environment was calculated as follows, and the environmental stability of the chargeability was evaluated according to the following criteria.
A: Charge retention (%) is 70% or more B: Charge retention (%) is 60% or more and less than 70% C: Charge retention (%) is 50% or more and less than 60% D: Charge retention (%) Is 40% or more and less than 50% E: Charge retention (%) is less than 40%

<Heat resistant storage stability>
5 g of toner particles are weighed into a 100 ml capacity polycup and placed in a thermostat with an internal temperature of 50 ° C. and left for 7 days. Thereafter, the polycup is taken out, and the state change of the toner inside is visually evaluated. Judgment criteria are as follows.
A: No change B: There are aggregates, but they are loosened immediately C: There are a few aggregates, but they are loosened when given an impact D: There are many aggregates and they are not easily loosened E: Each of the two produced Using the component developers, durability evaluation, low-temperature fixability evaluation, charge amount and charge stability evaluation were performed according to the following methods.

<Low temperature fixability>
First, the two-component developer is allowed to stand at high temperature and high humidity (30 ° C./80%) for 7 days, and then left at room temperature and normal humidity (23 ° C./60%) for another 3 days to reset the charge due to initial mixing. .

As a test machine, a commercially available full-color copying machine (CLC-700, manufactured by Canon Inc.) was used, and an unfixed toner image (toner applied amount per unit area of 0. 0 g / m ² ) on an image receiving paper (80 g / m ² ). 6 mg / cm ² ).

  The fixing test is performed using a fixing unit which is removed from the copying machine and modified so that the fixing temperature can be adjusted. The specific evaluation method is as follows.

  In a normal temperature and humidity environment (23 ° C, 60% RH), the process speed is set to 180 mm / s, the initial temperature is set to 120 ° C, and the set temperature is sequentially raised by 5 ° C, and the unfixed state at each temperature. Fix the image.

In the present invention, the low-temperature fixability indicates that the low-temperature offset is not observed and the obtained fixed image is rubbed before and after rubbing with sylbon paper applied with a load of 4.9 kPa (50 g / cm ² ). The temperature at which the density reduction rate of the toner was 10% or less was defined as the low temperature side fixing start point. The evaluation criteria for the low-temperature fixing performance are as follows.
A: The low temperature side fixing start point is 120 ° C. (low temperature fixing performance is particularly excellent)
B: Low temperature side fixing start point is 125 ° C. (low temperature fixing performance is good)
C: Low temperature side fixing start point is 130 ° C. (low temperature fixing performance is at a level where there is no problem)
D: low temperature side fixing start point is 135 ° C. (low temperature fixing performance is slightly inferior)
E: Low temperature side fixing start point is 140 ° C. (low temperature fixing performance is inferior)
The results are shown in Table 5.

  From the above results, the toner of the present invention has both heat-resistant storage stability and low-temperature fixability, has a sufficient charge amount, and has little decrease in chargeability in a high-temperature and high-humidity environment.

  Further, it was found that a sufficient charge amount cannot be obtained when resin fine particles containing only carboxyl groups as hydrophilic functional groups are used.

  It was found that when resin fine particles containing only a sulfonic acid group as a hydrophilic functional group are used, the chargeability is likely to deteriorate in a high temperature and high humidity environment.

  It was also found that if the difference between the glass transition temperatures of the core particles and the resin fine particles is too large, the chargeability of the obtained toner would be significantly lowered because of problems such as embedding or peeling of the resin fine particles.

  If the difference in the glass transition temperature between the core particles and the resin fine particles is too small, the toner particles may be significantly aggregated in the fixing step of the resin fine particles, and the core particles and the resin fine particles may be miscible, resulting in charging of the resulting toner. It was found that the performance was significantly reduced.

  Further, it has been found that when the glass transition temperature of the core particle and the resin fine particle deviates from the preferable range in the present invention, it is difficult to achieve both heat-resistant storage stability and low-temperature fixability.

DESCRIPTION OF SYMBOLS 1 Suction machine 2 Measuring container 3 Screen 4 Lid 5 Vacuum gauge 6 Air flow control valve 7 Suction port 8 Condenser 9 Electrometer

Claims (5)

A toner containing toner particles having core particles containing at least a binder resin, a colorant and a release agent, and a coating layer covering the core particles,
The coating layer is formed by forming resin particles on the surface of the core particles after forming the core particles,
The difference (Tg2−Tg1) (° C.) between the glass transition temperature Tg1 (° C.) of the core particles and the glass transition temperature Tg2 (° C.) of the resin fine particles is 5 to 40 ° C.
The resin fine particle is composed of a resin containing at least a carboxyl group and a sulfonic acid group, and the acid value derived from the carboxyl group of the resin fine particle is 3.0 to 20.0 mgKOH / g, The acid value derived from the sulfonic acid group of the fine particle is 2.0 to 15.0 mg KOH / g, and the total of the acid value derived from the carboxyl group and the acid value derived from the sulfonic acid group of the resin fine particle is 8 0.0 to 30.0 mg KOH / g ,
The toner, wherein the coating layer contains 0.005 to 0.050% by mass of sulfur element with respect to the toner particles. The toner according to the glass transition temperature Tg1 (° C.) is 請 Motomeko 1 Ru 20 to 60 ° C. der of the core particles. Toner of the coating amount of the coating layer is, according to 1.0 to 10.0 parts by mass der Ru請 Motomeko 1 or 2 with respect to the core particle 100 parts by weight. The core particles are obtained by dispersing a polymerizable monomer composition containing at least the polymerizable monomer, the colorant and the release agent in an aqueous medium, and polymerizing the polymerizable monomer. the toner according to any one of der Ru請 Motomeko 1 to 3 as a. A dispersion stabilizer is dispersed in a binder resin solution in which the core particles dissolve or disperse at least the binder resin, the colorant, and the release agent in a solvent capable of dissolving the binder resin. suspended in an aqueous medium having toner according to any one of der Ru請 Motomeko 1 to 3 which is manufactured through the step of removing the said solvent.