JP2011017983A - Method for producing toner for electrostatic charge image development and toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a toner allowing sharp distribution of toner particles without inducing aggregation of toner particles and having characteristics of fixability etc. suitable for high image qualities and a high-speed process.SOLUTION: The method for producing a toner includes: an emulsion polymerization step of preparing a dispersion liquid containing polymer primary particles by an emulsion polymerization method; an aggregation step of obtaining particle aggregates by aggregating the polymer primary particles and a colorant; an ageing step of producing toner base particles by fusing the particle aggregates; and a cooling step of cooling the dispersion liquid of the toner base particles. In the cooling step, an alkaline electrolyte is added to the dispersion liquid of the toner base particles.

Description

  The present invention relates to a method for producing a toner for developing an electrostatic image used in an image forming apparatus such as an electrophotographic copying machine or a printer, and a toner for developing an electrostatic image.

In recent years, applications of image forming apparatuses such as electrophotographic copying machines have been expanded, and accordingly, demands for various performances of toner used have become higher.
For example, with the speeding up of copying and printing, it is desired to increase the fixing speed of toner and the like. When the fixing process is high-speed, temperature unevenness on the surface of the fixing roller is more likely to occur due to the paper feed speed and the properties of the fixing member, etc., compared to when the fixing process is low-speed. As a result, image quality (particularly fixing strength and glossiness) is affected. receive. As a method of improving such a high-speed image defect, a method that can be dealt with by a fixing device capable of more precise temperature control can be considered, but the fixing device is complicated, large-sized, reduced in durability, and increased in cost. A problem occurs. Therefore, in order to obtain good image quality in high-speed copying and printing, a toner having a wider fixing temperature range in which no offset occurs during fixing is desired.

  In addition, there is an increasing demand for reduction of energy required for image formation, and power saving is required for a fixing process that consumes a large amount of energy. As a countermeasure for such power saving, a method for lowering the toner fixing temperature has been proposed. Generally, low-temperature fixing of the toner can be realized by lowering the glass transition temperature of the toner, but it is difficult to achieve both the storage stability of the toner. In other words, in order to achieve both low-temperature fixability and storage stability of the toner, it is desirable that the toner undergo a sufficiently large viscosity drop in the high temperature region while maintaining a glass transition temperature that does not deteriorate storage stability. In order to satisfy such a demand, a method of narrowing the molecular weight distribution of the resin constituting the toner has been proposed. However, such a toner has a new problem that an offset tends to occur in a high temperature region at the time of fixing. .

  As described above, in order to produce a toner satisfying various required performances such as high image quality and power saving, the molecular weight and molecular weight distribution of the resin constituting the toner, the resin distribution in the toner, the toner particle It is necessary to precisely control various parameters such as structure. Therefore, development of a toner manufacturing method capable of precisely controlling such various parameters and enabling various resin designs is required.

  Conventionally, a method for producing a toner for developing an electrostatic charge image that has been widely used includes a melt-kneading pulverization method. This method is a method in which various binder resins, a colorant and, if necessary, a charge control agent and a magnetic material are mixed, melt-kneaded by an extruder, and then pulverized and classified. However, this melt-kneading pulverization method has a limit in controlling the particle size of the toner, and it has been difficult to produce a toner having an average particle size of substantially 10 μm or less with a high yield. Therefore, it cannot be said to be sufficient to achieve the high resolution required for electrophotography.

On the other hand, in recent years, as a production method replacing the melt-kneading pulverization method, a toner production method by a wet polymerization method such as an emulsion polymerization aggregation method or a suspension polymerization method has been proposed. In particular, in the emulsion polymerization aggregation method, the particle size, particle size distribution, and shape of the obtained toner can be controlled relatively easily.
As a method for producing a toner by the emulsion polymerization aggregation method, first, a dispersion containing primary polymer particles having a particle diameter of about 0.05 μm to 0.5 μm obtained by emulsion polymerization is produced. Next, a pigment, a charge control agent or the like is added to the dispersion to aggregate the polymer primary particles, and the obtained aggregated particles are fused to obtain toner base particles. In this method, the particle characteristics of the toner particles such as particle diameter and particle shape have a great influence on the properties of the toner. Therefore, in order to produce a toner having the desired characteristics, the particle characteristics of the toner particles and the structure thereof are precise. Need to control.

  In order to realize low-temperature fixing, a method of mixing a low-melting wax or crystalline resin in the toner has been proposed (Patent Document 1). However, in this method, a low melting point component may ooze out on the toner surface when aggregation is performed, and toner aggregates such as dimers are generated and obtained by fusing the toners together during cooling. The toner quality was not stable and was a problem.

  In order to prevent the generation of toner aggregates, a capsule structure in which wax or the like does not ooze out on the toner surface has been proposed (Patent Document 2). However, in order to realize low-temperature fixability, it is necessary to distribute wax on the surface of the toner or in the vicinity of the surface, and sufficient studies have not been made on coexistence of prevention of aggregate formation and low-temperature fixability. .

JP 2004-251932 A Japanese Patent Laid-Open No. 11-231570

  The present invention has been made in view of the above-described circumstances, and does not cause aggregation of toners, has a sharp toner particle distribution, and has characteristics such as fixing properties suitable for high image quality and high speed. And a toner produced by the production method.

  As a result of intensive investigations by paying attention to the step of the emulsion polymerization aggregation method, the present inventors have found that the above problem can be solved by adding an electrolyte to the dispersion of toner base particles after the aging step. It came to complete.

That is, the gist of the present invention is as follows.
1. An emulsion polymerization step of producing a dispersion containing polymer primary particles by an emulsion polymerization method;
Agglomeration step of agglomerating the polymer primary particles and the colorant to obtain particle agglomerates;
An aging step of fusing the particle aggregates to produce toner mother particles;
An electrostatic charge image developing toner manufacturing method comprising a cooling step of cooling a dispersion of toner base particles, wherein an alkaline electrolyte is added to the dispersion of toner base particles in the cooling step. A method for producing a toner for image development.
2. 2. The method for producing a toner for developing an electrostatic charge image according to 1 above, wherein, in the cooling step, an alkaline electrolyte is added to the dispersion of the toner base particles, and then an acidic electrolyte is added.
3. 3. The electrostatic charge image developing toner according to 1 or 2 above, wherein in the cooling step, the addition start temperature of the alkaline electrolyte is equal to or higher than the glass transition temperature of the binder resin contained in the toner and the melting point of the crystalline substance. Manufacturing method.
4). 4. The method for producing a toner for developing an electrostatic charge image according to any one of 1 to 3, wherein, in the cooling step, the addition start temperature of the acidic electrolyte is not higher than the melting point of the crystalline substance contained in the toner.
5. An electrostatic charge image developing toner obtained by the production method according to any one of 1 to 4 above.

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner manufacturing method and a toner that do not cause toner aggregation, have a sharp toner particle distribution, and are suitable for high image quality and high speed by low-temperature fixing.
If toner particles agglomerate after the ripening step, the toner distribution becomes broad and the toner becomes unevenly charged during image formation, so that high image quality cannot be obtained. In addition, when external addition is performed, the external additive collects at a portion where the agglomerated toners are grounded, and uniform external addition may not be performed. In addition, when toner aggregated due to impact or the like is separated after external addition, the external additive is not attached to the portion where the toners are grounded, so that the toner is not uniformly charged or fogged. It may cause or the caking property may deteriorate.

The method for producing a toner for developing an electrostatic charge image of the present invention mainly comprises the following four steps, and is characterized in that an electrolyte is added to the dispersion of toner base particles in the cooling step in the emulsion polymerization method.
<Emulsion polymerization step> Step of producing dispersion containing polymer primary particles by emulsion polymerization method <Aggregation step> Step of aggregating polymer primary particles and colorant to obtain particle aggregate <Aging step> Particle aggregate Step for Producing Toner Base Particles by Fusing <Cooling Step> Step for Cooling Toner Base Particles Obtained in Aging Step Materials and procedures used in each step will be described below.

<Emulsion polymerization process>
In the present invention, as the binder resin contained in the toner, resins conventionally used as the binder resin for toner can be appropriately used.
In the present invention, a binder resin monomer (hereinafter sometimes referred to as a monomer) and a polymerization initiator are added to the “aqueous medium containing an emulsifier” in the reaction vessel in the emulsion polymerization step. The monomer is polymerized in an emulsified state to produce a polymer primary particle dispersion, which is subjected to an aggregation step. More specifically, in the emulsion polymerization method, at least one monomer, or an emulsion of the monomer, is supplied to an “aqueous medium containing an emulsifier” in a batch or continuous reaction vessel. The polymer is polymerized to produce polymer primary particles.
The monomers to be added may be added as they are, but the monomers may be added in the state of an emulsion. In order to obtain polymer primary particles having a narrow particle size distribution, it is preferable to add them to the polymerization apparatus in the form of a monomer emulsion. The monomer may be emulsified in a batch, or may be continuously emulsified and added to the polymerization apparatus.

  The polymerization conditions are appropriately selected in accordance with the monomers used, but the polymerization temperature is preferably 50 ° C or higher, more preferably 70 ° C or higher, and preferably 100 ° C or lower. More preferably, it is 95 degrees C or less.

  Hereinafter, the binder resin, surfactant, and other components (polymerization initiator, chain transfer agent, crosslinking agent, wax) used in the emulsion polymerization step will be described.

<Binder resin>
In the present invention, as the binder resin contained in the toner, resins conventionally used as the binder resin for toner can be appropriately used. For example, as a monomer, a polymerizable monomer having an acidic group (hereinafter sometimes simply referred to as an acidic monomer), a polymerizable monomer having a basic group (hereinafter simply referred to as a basic monomer) A polymerizable monomer having no acidic group or basic group (hereinafter, also referred to as other monomer) may be used. it can. Among these, it is preferable to use these monomers in combination.
The glass transition temperature of the binder resin of the present invention is preferably 40 ° C. or higher, more preferably 45 ° C. or higher. Moreover, it is preferable that it is 80 degrees C or less, More preferably, it is 75 degrees C or less.

  Examples of the monomer having an acidic group include monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and cinnamic acid, monomers having a sulfonic acid group such as sulfonated styrene, and vinyl. Examples thereof include monomers having a sulfonamide group such as benzenesulfonamide, among which monomers having a carboxyl group are preferable, and acrylic acid or methacrylic acid is particularly preferable.

  Examples of the monomer having a basic group include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocycle-containing monomers such as vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, and diethylaminoethyl methacrylate. Examples include (meth) acrylic acid esters having an amino group. The monomer having an acidic group and the monomer having a basic group may each exist as a salt with a counter ion.

The total amount of the monomer having an acidic group and the monomer having a basic group is preferably 0.01% by mass or more, more preferably 0.5% by mass or more, based on the total amount of monomers to be subjected to emulsion polymerization. In addition, the content is preferably 5% by mass or less, more preferably 3% by mass or less. By making the total amount of the monomer having an acidic group and the monomer having a basic group within the above range, the particle size can be easily controlled, which is preferable. Furthermore, the content of the monomer having an acidic group in all monomers constituting the polymer primary particles is preferably 3% by mass or less, more preferably 2% by mass or less. It is preferable that the content of the monomer having an acidic group is within the above range because the particle size can be easily controlled.
Usually, when the amount of the monomer having an acidic group is large, the dispersion stability in water is good and the particle size controllability in the aggregation process is excellent, but conversely, the amount of the monomer having an acidic group is small. If it is too large, particle size control may be difficult.

  Other monomers include styrene such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, pt-butylstyrene, pn-butylstyrene, pn-nonylstyrene; methyl acrylate, Ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl (Meth) acrylic acid esters such as hydroxyethyl acid and ethylhexyl methacrylate; acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylamide, N, N-dibutylacrylic And acrylic acid amides such as de like. Of these, styrene, butyl acrylate and the like are particularly preferable.

  Styrene is preferably used as the monomer used in the emulsion polymerization step. Further, it is preferable to use at least one selected from acrylic acid or alkyl ester of methacrylic acid as a copolymerization component in order to obtain a toner having a balanced performance.

<Water>
In this invention, when supplying a monomer with the form of a water emulsion, the density | concentration is not specifically limited, However, 10 mass% or more is preferable with respect to the total water emulsion liquid mass, and 40 mass% or less is preferable.

<Surfactant>
In the present invention, a surfactant may be used as necessary when performing chemical polymerization. In the case of using a monomer having a self-emulsifying ability (for example, Latemu from Kao Corporation, rear soap from Asahi Denka Kogyo Co., Ltd.), a surfactant is not essential.
The surfactant (emulsifier) used in the present invention is not particularly limited, and examples thereof include known surfactants such as a cationic surfactant, an anionic surfactant, and a nonionic surfactant. Two or more of these surfactants may be used in combination. The amount of surfactant used in the continuous monomer emulsification may be constant, but may vary depending on the progress of polymerization.

Specific examples of the cationic surfactant used as a surfactant (emulsifier) in the emulsion polymerization step include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, etc. Is mentioned.
Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate.
Furthermore, specific examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose, etc. Is mentioned.

  The amount of the surfactant used is appropriately selected according to the properties of the target toner, and is preferably 0.1 parts by weight or more with respect to 100 parts by weight of the monomer. 5 mass parts or less are preferable and 3 mass parts or less are more preferable. If it is in the said range, since it is excellent in stability of a polymer primary particle and it aggregates easily, it is preferable. When the amount used is larger than the above range, the latex is stable, but is not preferred because it is difficult to aggregate. On the other hand, if the amount used is less than the above range, a problem occurs in the stability of the polymer primary particles, the cohesive force becomes too strong, and coarse powder may be generated, which is not preferable.

<Polymerization initiator>
In the present invention, a polymerization initiator may be used as necessary when performing emulsion polymerization. As the polymerization initiator used in the present invention, a known polymerization initiator (for example, a water-soluble polymerization initiator) can be used, and one or a combination of two or more polymerization initiators can be used. For example, hydrogen peroxide; persulfates such as potassium persulfate; organic peroxides such as benzoyl peroxide and lauroyl peroxide; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2 , 4-dimethylvaleronitrile) and the like.
These polymerization initiators are combined with reducing agents such as reducing organic compounds such as ascorbic acid, tartaric acid and citric acid, and reducing inorganic compounds such as sodium thiosulfate, sodium bisulfite and sodium metabisulfite. It can also be a redox initiator. Of these, hydrogen peroxide, organic peroxides, and azo compounds are preferable as the initiator.

The amount of the polymerization initiator used is appropriately selected according to the properties of the target toner.
The polymerization initiator may be directly supplied to the batch reactor. It may be supplied together with a monomer and a surfactant, contained in the emulsion, and supplied to the reactor.

<Chain transfer agent>
In the present invention, when performing emulsion polymerization, a known chain transfer agent may be used as necessary. By using a chain transfer agent as described above, it is possible to more precisely control the molecular weight and molecular weight distribution of the resin constituting the polymer primary particles, and a desired toner can be easily produced.
Specific examples of the chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropyl xanthogen, carbon tetrachloride, trichlorobromomethane and the like.
The chain transfer agent may be used alone or in combination of two or more, and is preferably 5 parts by mass or less, more preferably 3 parts by mass or less with respect to 100 parts by mass of the monomer. Moreover, 0.01 mass part or more is preferable.

<Crosslinking agent>
In the present invention, a monomer having at least two functional groups (polyfunctional monomer) that acts as a cross-linking agent can be used as necessary when performing emulsion polymerization.
Although it does not restrict | limit especially as a polyfunctional monomer, Usually, what has radical polymerizability is used. Examples include divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, diallyl phthalate, and the like. It is also possible to use monomers having a reactive group as a pendant group, such as glycidyl methacrylate, methylol acrylamide, acrolein, and the like.

The content in the case of using a polyfunctional monomer is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0% in all monomers constituting the polymer primary particles. 0.05 mass% or more, preferably 5 mass% or less, more preferably 3 mass% or less, and still more preferably 1 mass% or less.
Moreover, it is preferable to contain said polyfunctional monomer so that the tetrahydrofuran (THF) insoluble content of a polymer primary particle may be 15 mass%-80 mass%.

<Wax>
In the present invention, when the wax is contained in the toner, the wax may be added in the aggregation step described later, or may be added in the emulsion polymerization step so that the wax is contained in the polymer primary particles.
When used in the emulsion polymerization step, a method of carrying out polymerization in the presence of a wax can be mentioned. More specifically, wax fine particles obtained by emulsification in the presence of an emulsifier are added in the emulsion polymerization step, and the monomer is emulsion polymerized using the wax fine particles as a seed, or the wax is dissolved in the monomer. Examples thereof include a method of emulsion polymerization. Among these methods, a method of adding wax fine particles obtained by emulsifying wax together with a long-chain polymerizable monomer such as stearyl acrylate in the presence of an emulsifier in the emulsion polymerization step is particularly preferable. By adding the wax in the emulsion polymerization step by such a method, the dispersion of the wax in the toner becomes good, and a large amount can be added. As a result, the release property and filming resistance of the obtained toner may be improved.

  The average particle size of the wax fine particles is not particularly limited when used as a seed or for co-aggregation, but is preferably 0.01 μm or more, more preferably 0.1 μm or more, and preferably 3 μm. Below, it is more preferably 2 μm or less, particularly preferably 1.5 μm or less. In addition, an average particle diameter can be measured using the Horiba LA-500, for example. When the average particle size is larger than 3 μm, it may be difficult to control the particle size during aggregation. Further, when the average particle size is smaller than 0.01 μm, it may be difficult to prepare a dispersion.

  Known waxes can be used as the wax in the present invention. Specifically, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene; paraffin wax; ester waxes having a long chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate; water Plant waxes such as soy castor oil and carnauba wax; ketones having long chain alkyl groups such as distearyl ketone; silicone waxes having alkyl groups; higher fatty acids such as stearic acid; long chain aliphatic alcohols such as eicosanol; glycerin, Examples include polyhydric alcohol carboxylic acid esters or partial esters obtained from polyhydric alcohols such as pentaerythritol and long chain fatty acids; higher fatty acid amides such as oleic acid amide and stearic acid amide; low molecular weight polyesters.

  The melting point of the wax of the present invention is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher in order to further improve the toner fixability. Moreover, 100 degrees C or less is preferable and 90 degrees C or less is still more preferable. If the melting point is too low, the wax is exposed on the surface after fixing, and stickiness tends to occur. If the melting point is too high, the fixing property at low temperatures may be inferior.

  In the present invention, one type of wax may be used, or several types may be used. The amount of wax used in the toner is not particularly limited, but is preferably 0.1% by mass or more, more preferably 1% by mass or more, particularly preferably 5% by mass or more, and most preferably 7%, based on the total mass of the toner. It is at least mass%, preferably at most 40 mass%, more preferably at most 35 mass%, particularly preferably at most 30 mass%.

  The toner of the present invention contains a crystalline substance. The crystalline substance is not particularly specified, but refers to a substance having a melting point such as the wax of the present invention. The melting point of the crystalline material of the present invention is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher in order to further improve the toner fixability. Moreover, 100 degrees C or less is preferable and 90 degrees C or less is still more preferable.

<Polymer primary particles>
The volume median diameter of the polymer primary particles obtained in the above process is appropriately selected according to the properties of the target toner, but is preferably 0.02 μm or more, preferably 0.05 μm or more. More preferably, it is more preferably 0.1 μm or more. Moreover, 3 micrometers or less are preferable, 2 micrometers or less are more preferable, and 1 micrometer or less are further more preferable. The volume median diameter of the polymer primary particles can be controlled by the concentration of raw materials such as emulsifiers, monomers, initiators, polymerization conditions, and the like.

  The volume median diameter can be measured by the method described in the examples. When the volume median diameter of the polymer primary particles is smaller than the above range, it may be difficult to control the aggregation rate. On the other hand, if it is larger than the above range, the particle size of the toner base particles obtained by agglomeration becomes too large, which may be inappropriate for applications requiring high resolution as a toner.

<Aggregation process>
In the aggregation step, the polymer primary particles obtained in the emulsion polymerization step, the colorant, and the charge control agent, wax, and other components used as necessary are aggregated. In the aggregating step, the agglomeration is performed up to the size of toner particles prior to the aging step described later.
In the aggregation step, the polymer primary particles, the colorant, the charge control agent added as necessary, the wax, and other compounding components can be mixed simultaneously or sequentially. In addition, from the viewpoints of compositional uniformity and particle size uniformity, a dispersion of each component, that is, a polymer primary particle dispersion, a colorant dispersion, a charge control agent dispersion, and a wax fine particle dispersion is prepared in advance. It is preferable that these are mixed to form a mixed dispersion and then aggregated.
First, materials used in the aggregation process will be described in detail below.

<Colorant>
The colorant of the present invention may be an inorganic pigment, an organic pigment, an organic dye, or a combination thereof. The colorant may be chromatic or achromatic.

  Specific examples of the colorant include carbon black as an achromatic colorant. Examples of the chromatic colorant include a cyan colorant, a yellow colorant, and a magenta colorant. Specifically, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes, disazo dyes, condensed azo dyes Any known dyes and pigments can be used alone or in combination.

In the case of a full color toner, yellow colorants include benzidine yellow, monoazo and condensed azo dyes, magenta colorants include quinacridone and monoazo dyes, and cyan colorants include phthalocyanine blue. Are preferably used respectively.
Specifically, as the cyan colorant, C.I. I. Pigment Blue 15: 3, and yellow colorants include C.I. I. Pigment yellow 74, C.I. I. Pigment Yellow 93 and magenta colorants include C.I. I. Pigment red 238, C.I. I. Pigment red 269, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 48: 2, C.I. I. Pigment Red 122 is particularly preferably used.

The colorant is preferably used in a state of being emulsified in water by a mechanical means such as a sand mill or a bead mill in the presence of an emulsifier, and more specifically, an organic pigment that is substantially insoluble in water is used as a surfactant. Finely dispersed in water in the presence of Under the present circumstances, it is good to add 10-15 mass parts of colorants and 1-15 mass parts of emulsifiers with respect to 100 mass parts of water. The volume median diameter of the colorant in the dispersant is preferably 0.01 μm or more, more preferably 0.05 μm or more, and preferably 3 μm or less, more preferably 1 μm.
Although the usage-amount of a coloring agent is not restrict | limited in particular, It is preferable to use it so that it may become 3 to 20 mass parts with respect to 100 mass parts of polymer primary particles.

<Charge control agent>
A charge control agent may be added to the toner used in the present invention in order to impart charge amount and charge stability. As the charge control agent, any known one can be used alone or in combination. For example, positively chargeable charge control agents include quaternary ammonium salts and basic / electron donating metal materials, and negatively chargeable charge control agents include metal chelates, metal salts of organic acids, and metal-containing metals. Examples thereof include dyes, nigrosine dyes, amide group-containing compounds, phenol compounds, naphthol compounds and their metal salts, urethane bond-containing compounds, and acidic or electron-withdrawing organic substances.

  In addition, when the toner for developing an electrostatic image obtained by the production method of the present invention is used as a toner other than a black toner in a color toner or a full color toner, a colorless or light-color charge control agent that does not impair the color tone of the toner is used. It is preferable to use it. For example, a quaternary ammonium salt compound is used as the positively chargeable charge control agent, and a metal salt of salicylic acid or alkylsalicylic acid with chromium, zinc, aluminum or the like, a metal complex, or a metal salt of benzylic acid as the negatively chargeable charge control agent. , Metal complexes, amide compounds, phenol compounds, naphthol compounds, phenolamide compounds, and hydroxynaphthalene compounds such as 4,4′-methylenebis [2- [N- (4-chlorophenyl) amido] -3-hydroxynaphthalene] are preferred.

In the present invention, when a charge control agent is contained in the toner by the emulsion polymerization aggregation method, the charge control agent is added together with a polymerizable monomer or the like at the time of emulsion polymerization, or the aggregation step is performed together with the polymer primary particles and the colorant. Or by adding the polymer primary particles and the colorant after agglomeration of the polymer primary particles and the colorant to a target particle size. Among these, it is preferable to disperse the charge control agent in water using a surfactant and add it to the aggregation step as a dispersion having a volume average particle size of 0.01 μm or more and 3 μm or less.
The amount of charge control agent used may be determined by the desired charge amount for the toner, but is usually preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight with respect to 100 parts by weight of the polymer primary particles. It is above, Preferably it is 10 mass parts or less.

<Wax>
In the toner used in the present invention, a wax can be used to improve fixability. As the wax to be used, the wax described in the emulsion polymerization step can be used.

<Aggregating method>
Examples of the coagulation method include a method of heating in a stirring tank, a method of adding an electrolyte, or a method of combining them. When polymer primary particles are agglomerated under stirring, the particle size of the particle aggregate is controlled by the balance between the agglomeration force between the particles and the shearing force by agitation, but the aggregation force is adjusted by heating or adding an electrolyte. And it can be set as the target particle size.

As an electrolyte when aggregation is performed by adding an electrolyte, either an organic salt or an inorganic salt may be used. Specifically, inorganic salt having a monovalent metal cation such as NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , CH ₃ COONa, C ₆ H ₅ SO ₃ Na; MgCl ₂ , inorganic salts having a divalent metal cation such as CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ ; inorganic having a trivalent metal cation such as Al ₂ (SO ₄ ) ₃ , Fe ₂ (SO ₄ ) ₃ Examples include salts. By using the electrolyte, it becomes easy to control the average particle size and particle size distribution of the aggregated particles, the charge amount distribution of the obtained toner becomes sharp, and an image free from fogging can be obtained.

The amount of electrolyte added varies depending on the type of electrolyte, target particle size, etc., but is usually 0.05 parts by mass or more, preferably 0.1 parts by mass with respect to 100 parts by mass of the solid component of the mixed dispersion. In addition, it is usually 25 parts by mass or less, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less. If the amount added is less than the above range, the progress of aggregation is delayed and fine powders of 1 μm or less remain after the aggregation treatment, or the average particle size of the obtained particle aggregate does not reach the target particle size. May occur. In addition, when the addition amount is larger than the above range, the aggregation tends to proceed rapidly, making it difficult to control the particle size, and there are problems such as inclusion of coarse particles or irregular shapes in the obtained particle aggregate. May occur.
The aggregation temperature in the case of performing aggregation by adding an electrolyte is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and preferably 70 ° C. or lower, more preferably 60 ° C. or lower.

  When the aggregation is performed only by heating without using an electrolyte, the aggregation temperature is preferably (Tg−20 ° C.) or more, more preferably (Tg−10 ° C.) when the glass transition temperature of the polymer primary particles is “Tg”. ) Or more, and preferably Tg or less, more preferably (Tg-5 ° C.) or less. When the temperature is less than the above range, the target particle size may not be reached. When the temperature is above the above range, the target particle size may be larger.

The time required for agglomeration is optimized depending on the device shape and processing scale, but in order to reach the target volume median diameter (Dv50), it is usually held at the above-mentioned predetermined temperature for at least 30 minutes. Is desirable. The temperature rise until reaching the predetermined temperature may be raised at a constant rate, or may be raised stepwise.
The volume median diameter (Dv50) of the aggregate obtained in this step is not particularly limited, but is preferably 3 μm or more, more preferably 4 μm or more, and preferably 9 μm or less, more preferably 8 μm or less.

<Aging process>
In the ripening step, the aggregate obtained in the above aggregation step is heated to fuse the polymer primary particles and the colorant, the wax added if necessary, the charge control agent, other components, etc. This is a step of forming a single particle (toner base particle).

The temperature of the ripening step is preferably not less than the glass transition temperature (Tg) of the polymer primary particles constituting the particle aggregate, more preferably not less than 5 ° C higher than Tg, and preferably not less than 80 ° C higher than Tg. Hereinafter, more preferably, the temperature is 50 ° C. or higher than Tg.
The time required for the aging step varies depending on the target shape, but after reaching the glass transition temperature of the polymer primary particles constituting the particle aggregate, it is usually 0.1 hour to 10 hours, preferably 1 hour. It is desirable to hold for ~ 6 hours.

  By heat treatment in the aging step, the polymer primary particles in the particle aggregate are fused and integrated with each other, and the particle aggregate has a shape close to a sphere. The particle aggregate before the aging step is considered to be an aggregate formed by electrostatic or physical aggregation using polymer primary particles as the main constituent. After the ripening step, the polymer primary particles constituting the particle aggregate are fused to each other, and toner mother particles having a nearly spherical shape can be obtained. According to such an aging process, by controlling the temperature and time of the aging process, the primary shape of the polymer primary particles is agglomerated, a potato type with advanced fusion, and a spherical shape with further fusion For example, toner base particles having various shapes (circularity) can be produced according to the purpose.

<Cooling process>
In the present invention, it is essential to add an alkaline electrolyte in the cooling step after the aging step. In the ripening step, heat treatment is performed for fusing and integrating the primary polymer particles in the particle aggregate. After that, the temperature of the dispersion of the toner base particles is the temperature of the binder resin that is a component of the toner. The temperature changes from a temperature range higher than the glass transition temperature or the melting point of the crystalline substance contained in the toner to a lower temperature range. Wax, which is a crystalline substance distributed in the vicinity of the surface of the binder resin in the temperature range including the glass transition temperature of the binder resin or the melting point of the crystalline substance due to changes in the fluidity of the resin. Or the like may be exposed on the surface of the toner, and the toner may aggregate. In the present invention, in the cooling step, the generation of aggregates is prevented by adding an alkaline electrolyte to the dispersion of toner base particles. The mechanism for preventing this occurrence is not clear, but by adding an electrolyte to the dispersion of toner base particles that has been in a stable state and adjusting the pH of the dispersion, the functional groups on the toner surface have a charge so that the toners It is conceivable that the toner base particles do not aggregate. For example, when butyl acrylate is used as the toner binder resin, a carboxyl group exists on the surface of the toner base particles, and by adding an alkaline electrolyte thereto, hydrogen is generated from the carboxyl groups on the surface of the toner base particles. Ionize. Due to the charge of each toner, the toners repel each other and no toner aggregates are generated.
The electrolyte may be added in the step before the cooling step, but the effect of the present invention can be obtained by newly adding the electrolyte in the cooling step. This effect is also shown in the examples.

In the present invention, the addition of the alkaline electrolyte is not particularly limited as long as it is a cooling step, but it is added at a temperature higher than the glass transition temperature of the binder resin that is a component of the toner and the melting point of the crystalline substance contained in the toner. Is preferable in order to prevent aggregation of the toner base particles.
In addition, the addition of an electrolyte near the aging temperature has an effect of promoting the circularization of the toner, and can also be used for controlling the circularization of the toner.

The alkaline electrolyte used in the present invention is not particularly limited and may be solid or liquid, but addition in liquid is preferable. By adding the alkaline electrolyte, the pH of the toner mother particle dispersion is increased, and further, the alkaline electrolyte reacts with the components on the toner surface, so that the stability of the individual toner particles is increased, and the toner aggregate during cooling is increased. Occurrence can be prevented.
The alkaline electrolyte used in the present invention may be any of alkali metal compounds such as Na and Li; alkaline earth metal compounds such as Mg and Ca, basic salts, and basic oxides. In order to change the pH of the aggregation liquid more effectively and prevent aggregation, Na ₂ CO ₃ , LiOH, NaOH, KOH, RbOH, CsOH, N (CH ₃ ) ₄ OH, N (C ₂ H ₅ ) ₄ Strong alkalinity such as OH, Ca (OH) ₂ , Ba (OH) ₂ , Sr (OH) ₂ is preferable, and alkali metal hydroxide is particularly preferable.

In the present invention, the concentration and addition amount of the alkaline electrolyte are not particularly limited, and are adjusted according to the pH value at the end of the addition, the volume of the reaction vessel, and the degree of aggregation of the toner base particles.
The pH value of the dispersion of the toner base particles at the end of addition of the alkaline electrolyte is appropriately changed depending on the binder resin component of the toner, but is preferably at least 1 higher than the pH of the liquid at the end of the aging step, and higher by 2 or more. Is more preferable. This is for preventing aggregation of the toner base particles and further preventing impurities such as an emulsifier used in the aggregation and aging process from adhering to the toner base particles. When there are many impurities in the toner base particles, charging defects and fogging occur, which is not preferable.

  In the present invention, the addition of an alkaline electrolyte in the cooling step can prevent the generation of toner mother particle aggregates. However, the addition of an alkaline electrolyte may change the surface state of the toner base particles, which may cause toner charge deterioration. In this case, it is preferable to adjust the pH by adding an alkaline electrolyte and then adding an acidic electrolyte in order to maintain toner performance. Although this mechanism is not clear, an alkaline electrolyte is added, and then an acidic electrolyte is added to bring the surface state of the toner base particles closer to the state at the end of ripening while preventing aggregation and dispersion of the toner base particles. And toner performance can be maintained.

  In the present invention, the addition of the acidic electrolyte is not particularly limited as long as the addition of the alkaline electrolyte is performed, but the addition of the acidic electrolyte at a temperature lower than the melting point of the crystalline substance contained in the toner is effective in the dispersion state of the toner base particles. It is preferable because it is sustained.

The acidic electrolyte used in the present invention is not particularly limited and may be solid or liquid, but addition in liquid is preferable. The acidic electrolyte used in the present invention is not particularly limited, and is a strong acid such as HI, HClO ₄ , HCl, HBr, H ₂ SO ₄ , HNO ₃ NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li _2. Inorganic salts having a monovalent metal cation such as SO ₄ , CH ₃ COONa, C ₆ H ₅ SO ₃ Na; inorganic having a divalent metal cation such as MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO _{4 salt; Al 2 (SO 4) 3} , Fe 2 (SO 4) 3 inorganic salts with trivalent metal cations, and the like. In order to change the pH of the dispersion of toner base particles more effectively, a strong acid is preferable.

In the present invention, the concentration and addition amount of the acidic electrolyte are not particularly limited, and are adjusted according to the pH value of the dispersion of the toner base particles, the volume of the reaction vessel, and the addition amount of the alkaline electrolyte.
The pH value of the dispersion of the toner base particles at the end of the addition of the acidic electrolyte varies depending on the pH value at the end of the addition of the alkaline electrolyte, but is preferably one or more lower than the pH of the solution at the end of the addition of the alkaline electrolyte. More preferably, it is lower. This is for preventing aggregation of the toner base particles and further stabilizing the surface state of the toner base particles.

<Washing and drying process>
The toner base particles that have undergone the above steps are solid-liquid separated according to a known method, and the toner base particles are collected, then washed as necessary, and dried to obtain the target toner base particles. Obtainable.

<External addition process>
The toner for developing an electrostatic charge image of the present invention may remain as the toner base particles obtained in the above step, but a known external additive is added to the toner base particles in order to control fluidity and developability. It may be done.
External additives include metal oxides and hydroxides such as alumina, silica, titania, zinc oxide, zirconium oxide, cerium oxide, talc and hydrotalcite, titanium such as calcium titanate, strontium titanate and barium titanate. Examples thereof include acid metal salts, nitrides such as titanium nitride and silicon nitride, carbides such as titanium carbide and silicon carbide, and organic particles such as acrylic resins and melamine resins. Among these, silica, titania, and alumina are preferable, and those that have been surface-treated with, for example, a silane coupling agent or silicone oil are more preferable. The average particle diameter is preferably 1 nm or more, more preferably 5 nm or more, and preferably 500 nm or less, more preferably 100 nm or less. It is also preferable to use a combination of a small particle size and a large particle size in the above particle size range. The total amount of the external additive added is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 10 parts by mass or less, with respect to 100 parts by mass of the toner base particles. More preferably, it is 5 mass parts.

  As a method for adding an external additive to the surface of the toner base particles, for example, in a high-speed fluid mixer such as a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) Is appropriately set and stirred and mixed uniformly. It can also be fixed by a device capable of applying a compressive shear stress.

<Toner for electrostatic image development>
The toner for developing an electrostatic charge image of the present invention has a volume median diameter of preferably 3 μm or more, more preferably 4 μm or more, and preferably 9 μm or less, more preferably 8 μm or less.
Further, the content ratio of fine powder particles having a volume median diameter of 5.04 μm or less is preferably 0.1% by volume or more, more preferably 0.5% by volume or more, particularly preferably based on the total toner volume. Is 1% by volume or more. On the other hand, the upper limit is preferably 10% by volume or less, more preferably 7% by volume or less, and particularly preferably 5% by volume or less. The content ratio of coarse powder particles having a volume median diameter of 12.7 μm or more is preferably 2% by volume or less, more preferably 1% by volume or less, and particularly preferably 0.5% by volume or less with respect to the total toner volume. It is. It is most preferable that the toner having a volume median diameter of 5.04 μm or less and the toner having a volume median diameter of 12.7 μm or more, particularly, coarse powder particles having a volume median diameter of 12.7 μm or more do not exist at all. It is difficult to manufacture and requires equipment for the removal process, so it is desirable to control within the above range. When the volume median diameter or particle content ratio deviates from the above range, it may not be suitable for high-resolution image formation, and if it is less than the above range, handling as a powder tends to be difficult.

  Further, the value (Dv50 / Dn50) obtained by dividing the volume median diameter (Dv50) by the number median diameter (Dn50) is preferably 1.25 or less, more preferably 1.20 or less, and particularly preferably 1.15 or less. And the lower limit is preferably 1.0. Since the electrostatic charge image developing toner has a sharper particle size distribution, the chargeability between the particles tends to be uniform. Therefore, the electrostatic charge image developing toner (Dv50 / Dn50) for achieving high image quality and high speed can be obtained. ) Is preferably within the above range. The volume median diameter (Dv50) and the number median diameter (Dn50) are measured and defined by the method described in the examples.

Further, the shape of the obtained toner for developing an electrostatic image is preferably as close to a sphere as possible, and the average circularity is preferably 0.90 or more, more preferably 0.92 or more, and particularly preferably 0.95 or more. The closer to a sphere, the less the localization of the charge amount in the particles and the development property tends to be uniform. However, since it is difficult to produce a perfect spherical toner, the average circularity is preferably Is 0.995 or less, more preferably 0.990 or less. The average circularity is
Measured by the method described in the examples and defined as a value obtained by such measurement.

  The electrostatic charge image developing toner of the present invention may be positively charged or negatively charged, but is preferably used as a negatively charged toner. Control of the chargeability of the toner can be adjusted by selection and content of the charge control agent, selection and addition amount of the external additive, and the like. The electrostatic image developing toner of the present invention can be suitably used for any of black toner, color toner, and full color toner.

  The toner for developing an electrostatic charge image of the present invention is a magnetic two-component developer that coexists with a carrier for conveying the toner to the electrostatic latent image portion by magnetic force, or a magnetic toner that contains magnetic powder in the toner. It may be used for either a component developer or a non-magnetic one-component developer that does not use magnetic powder as a developer. However, in order to exhibit the effects of the present invention remarkably, a non-magnetic one-component development is particularly preferred. It is preferably used as a developer for the system.

  When used as the above-mentioned magnetic two-component developer, the carrier that forms the developer by mixing with the toner is a known magnetic substance such as an iron powder-based, ferrite-based, or magnetite-based carrier, or the surface thereof. A resin-coated one or a magnetic resin carrier can be used. As the carrier coating resin, generally known styrene resins, acrylic resins, styrene acrylic copolymer resins, silicone resins, modified silicone resins, fluorine resins, and the like can be used, but are not limited thereto. It is not a thing. The average particle diameter of the carrier is not particularly limited, but preferably has an average particle diameter of 10 μm to 200 μm. These carriers are preferably used in an amount of 5 to 100 parts by mass with respect to 1 part by mass of the toner.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “part” means “part by mass”. In addition, the live-action test was conducted by the following method.

  Each particle diameter, average circularity, electrical conductivity, thermal characteristics, etc. were measured as follows.

<Measurement of volume median diameter and number median diameter>
The volume median diameter and number median diameter of particles having a diameter of 1 micron or more were measured using Beckman Coulter's Multisizer III (aperture diameter 100 μm: hereinafter abbreviated as Multisizer), and the company's Isoton II was used as the dispersion medium. As a result, the dispersion was measured so that the dispersoid concentration was 0.03%. The measurement particle diameter range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and the volume calculated based on the statistical values on the basis of the volume is the volume. The median diameter was calculated based on the statistical value on the basis of the number, and the median diameter was determined.

<Method for measuring volume median diameter of less than 1 μm>
Further, the volume median diameter of particles having a volume median diameter of less than 1 μm was measured using Nikkiso Co., Ltd. model Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”) and company analysis software Microtrac Particle Analyzer Ver10.1.2-019EE. Measured by the method described in the instruction manual under the measurement conditions of solvent refractive index: 1.333, measurement time: 600 seconds, number of measurements: 1 time, using ion-exchanged water having an electric conductivity of 0.5 μS / cm as a solvent. did. Other setting conditions were particle refractive index: 1.59, transparency: transmission, shape: true sphere, density: 1.04.

<Measuring method and definition of average circularity>
The average circularity is 5720 to 71 when the dispersoid is used as a dispersion medium (Cell sheath: manufactured by Sysmex Corporation).
It was dispersed so as to be in the range of 40 particles / μL, and measured by using a flow type particle image analyzer (manufactured by Sysmex Corporation (former Toa Medical Electronics), FPIA2100) under the following apparatus conditions. The value is defined as “average circularity”. In the present invention, the same measurement is performed three times, and an arithmetic average value of three “average circularity” is adopted as the “average circularity”.
・ Mode: HPF
-HPF analysis amount: 0.35 μL
-Number of HPF detection: 2000 to 2500

The following “circularity” is measured by the above-mentioned device, and is automatically calculated and displayed in the above-mentioned device, and “circularity” is defined by the following equation.
[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
Then, 2000 to 2500 HPF detection numbers are measured, and the arithmetic average (arithmetic mean) of the circularity of each individual particle is displayed on the apparatus as “average circularity”.

<Method of measuring electrical conductivity>
The electrical conductivity was measured using a conductivity meter (CyberScanCON100 manufactured by ASONE Corporation).

<Measurement method of mass average molecular weight (Mw)>
A 0.1% by mass THF solution of the measurement sample was prepared, allowed to stand for 4 hours, and then filtered using a Kurabo Industries GL Chromatodisc (sample pretreatment filter) 13P. The THF soluble component was measured by gel permeation chromatography (GPC) under the following conditions.
Apparatus: GPC apparatus HLC-8020 manufactured by Tosoh Corporation
Column: PL-gel Mixed-B 10μ made by Polymer Laboratory,
Solvent: THF,
Sample concentration: 0.1% by mass,
Calibration curve: prepared using standard polystyrene

<Measuring method of glass transition temperature>
Using a differential scanning calorimeter DSC 6220 manufactured by SII Nanotechnology, Inc., the temperature was measured at a rate of 10 ° C./min. The glass transition temperature was determined from the intersection of the extension line of the base line of the DSC curve and the tangent line showing the maximum inclination in the endothermic curve, using analysis software (EXSTAR6000 thermal analysis rheology system) attached to the apparatus. Instead of adopting the theoretical glass transition temperature as the above glass transition temperature when the glass transition temperature cannot be clearly determined due to changes in the amount of heat of other components other than resin, for example, wax, etc., differential scanning of wax, etc. The measurement was performed on the resin prepared by removing the components that hinder measurement of the calorimeter.

<Measuring method of melting point>
Measure the melting point from the endothermic curve when the temperature was raised from 10 ° C to 110 ° C at a rate of 10 ° C / min by using the SSC5200 manufactured by Seiko Instruments Inc. did.

<Example 1>
<Preparation of wax dispersion>
30 parts of paraffin wax (Nippon Seiki HNP-9, melting point 75 ° C.), 20% sodium dodecylbenzenesulfonate aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A) (hereinafter abbreviated as “20% DBS aqueous solution”) ) 2.8 parts and 67.2 parts of demineralized water were heated to 90 ° C. and stirred for 10 minutes using a homomixer (Mark II f model, manufactured by Tokushu Kika Kogyo Co., Ltd.).

  Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin Co., Ltd., 15-M-8PA type). A wax dispersion was prepared by dispersing until the average diameter (Mv) reached 250 nm.

<Preparation of polymer primary particle dispersion>
A reactor equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device was charged with 36.3 parts of the wax dispersion A1 and 259 parts of demineralized water, and nitrogen. The temperature was raised to 90 ° C. under an air stream.

  Thereafter, the following monomer / emulsifier mixture was added over 4 hours while stirring was continued. The time when the mixture of the monomers and the emulsifier aqueous solution was added dropwise was set as the polymerization start, the following initiator aqueous solution 1 was added over 3.5 hours after 30 minutes from the start of polymerization, and the following initiator aqueous solution 2 was added for 2 hours. Added over time. Thereafter, the inner temperature was maintained at 90 ° C. for 1 hour under stirring.

[Monomers]
74.5 parts of styrene
Butyl acrylate 25.5 parts Acrylic acid 1.5 parts Trichlorobromomethane 1.0 part Hexanediol diacrylate 0.7 part

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part demineralized water 67.1 parts

[Initiator aqueous solution 1]
8% aqueous hydrogen peroxide solution 15.5 parts 8% L (+)-ascorbic acid aqueous solution 15.5 parts

[Additional initiator aqueous solution 2]
8% L (+)-ascorbic acid aqueous solution 14.2 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion. The volume average diameter (Mv) of the polymer primary particles was 220 nm. The glass transition temperature of the binder resin measured using DSC was 52 ° C., and the mass average molecular weight (Mw) was 88,800.

<Colorant Dispersion-1> An aqueous dispersion of quinacridone magenta PR122 (EP1210 Red, manufactured by Dainichi Seika Co., Ltd., solid content 20%), and the average particle size measured by UPA was 150 nm.

<Manufacture of development mother particle C1>
A mixer equipped with a stirrer (double helical blade), heating / cooling device, concentrating device, and each raw material / auxiliary charging device was charged with 80 parts (solid content) of polymer primary particle dispersion B1 and the internal temperature was set to 20 ° C. Then, 0.1 part (solid content) of 20% DBS aqueous solution was added and mixed uniformly. Further, a 5% aqueous solution of ferrous sulfate (0.53 parts as FeSO ₄ .7H ₂ O) was added over 5 minutes, and stirring was continued for 5 minutes to mix uniformly. Subsequently, 8.0 parts (solid content) of Colorant Dispersion-1 was added over 5 minutes and mixed uniformly, and then 0.2 part of 0.5% aqueous aluminum sulfate solution (solid content) was added dropwise. During this time, the internal temperature was kept at 20 ° C. Thereafter, the internal temperature was raised to 54 ° C. over 30 minutes, and the temperature was further maintained at 54 ° C. over 50 minutes. Here, the volume-median particle size (Dv50) was measured using a multisizer and found to be 5.3 μm. Thereafter, 20 parts (solid content) of polymer primary particle dispersion B1 was added over 3 minutes and held for 30 minutes, followed by 6 parts of 20% DBS aqueous solution (solids) and 22.4 parts of demineralized water, respectively. After addition over 10 minutes, the temperature was raised to 95 ° C. over 30 minutes and held for 40 minutes. The toner mother particle dispersion measured using a pH meter had a pH of 3, and the volume median particle size (Dv50) of the aggregated particles measured using Multisizer III was 5.7 μm. The measured average circularity was 0.97.
Thereafter, the mixture was cooled to 90 ° C. over 15 minutes, 1.2 parts (solid content) of NaOH (1N) aqueous solution was added, and the mixture was cooled to 65 ° C. over 15 minutes. The pH at this time was 7. Further, 1.6 parts (solid content) of an HNO ₃ (1N) aqueous solution was added, and the mixture was cooled to 30 ° C. over 15 minutes. The pH at this time was 4.

The obtained slurry was extracted and subjected to suction filtration with an aspirator using 5 types C (No. 5C manufactured by Toyo Roshi Kaisha, Ltd.) filter paper. The cake remaining on the filter paper is transferred to a stainless steel container with an internal volume of 10 L equipped with a stirrer (propeller blade), added with 8 kg of ion-exchanged water having an electric conductivity of 1 μS / cm, and uniformly dispersed by stirring at 50 rpm. Stirred for 30 minutes.
After that, using 5 C filter paper again, it is suction filtered with an aspirator. The solid matter remaining on the filter paper is equipped with a stirrer (propeller blade) and contains 8 kg of ion-exchanged water with an electric conductivity of 1 μS / cm. The product was transferred to a stainless steel container having a volume of 10 L and uniformly dispersed by stirring at 50 rpm, and stirring was continued for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.
The cake obtained here was spread on a stainless steel bat so as to have a height of 20 mm, and dried for 48 hours in a blow dryer set at 40 ° C., thereby obtaining developing mother particles C1.
The volume median particle diameter (Dv50) of the developing mother particle C1 measured using Multisizer III was 5.7 μm, and the average circularity measured by a flow particle analyzer was 0.97.

<Manufacture of developing toner D1>
100 parts of toner base particles C1 are put into Kyoritsu Riko Co., Ltd. sample mill KR-3, and then 1.5 parts of silica fine particles having a volume average primary particle size of 0.015 μm hydrophobized with silicone oil are added. Then, a developing toner D1 was obtained by stirring, mixing and sieving.

<Example 2>
<Production of developing mother particle C2>
Developing mother particles C2 were obtained in the same manner as C1, except that HNO ₃ was not added during cooling. The volume median particle size (Dv50) was 5.7 μm, and the average circularity measured by a flow particle analyzer was 0.97.

<Manufacture of developing toner D2>
A developing toner D2 was obtained in the same manner as D1, except that C3 was used instead of the developing mother particle C1.

<Comparative Example 1>
<Production of developing mother particle C3>
Developing mother particles C3 were obtained in the same manner as C1, except that no electrolyte (NaOH, HNO ₃ ) was added during cooling. The volume median particle size (Dv50) was 7.0 μm, and the average circularity measured by a flow particle analyzer was 0.92.

<Manufacture of developing toner D3>
A developing toner D3 was obtained in the same manner as in D1, except that C3 was used instead of the developing mother particle C1.

Table 1 shows the evaluation results using the developing toners D1 to D3.
<Image quality evaluation>
The obtained toner is an organic photosensitive member charged with a developing rubber roller, a metal blade, a charging roller (PCR) at a printing speed of 100 mm / s, a non-magnetic one component, a guaranteed number of 10,000 sheets (at 5% printing), a belt transfer, Using a full color printer equipped with a belt fixing machine using a thermal fixing system, continuous printing of 10,000 sheets was performed at a printing rate of 5%.
<PC cover>
Using an image forming apparatus, the color difference of the white background portion of each standard paper (FC Dream; manufactured by Kishu Paper Co., Ltd.) before and after printing was measured with X-Rite 938 (manufactured by X-Rite). Judging from the size of E, the following criteria were used.
◎ (Good): △ E <0.8
○ (Slightly generated): 0.8 ≦ ΔE <1.2
X (Generation): 1.2 ≦ ΔE

<Blocking resistance>
10 g of developing toner is put in a cylindrical container having an inner diameter of 3 cm and a height of 6 cm, a load of 20 g is put on it, left in an environment of 50 ° C. and 40% RH for 24 hours, the toner is taken out of the container, and the load is applied from above. The degree of aggregation was confirmed by applying.
○ (Practical use possible): It collapses with a load of less than 200 g.
X (Unusable): Aggregates and does not collapse unless a load of 200 g or more is applied.

<Fluidity>
In an environment with a humidity of 25 ° C and a humidity of 40%, the aperture of the iris diaphragm (manufactured by Koyo Co., Ltd., 1-33 mm variable aperture) is 1 mm, and the developing toner is placed on the sample holding cylinder (inner diameter 33 mm) placed on the iris diaphragm. 3 g of sample is put, and the aperture is opened by 1 mm along the scale of the iris aperture so as not to give vibration from the aperture diameter of 1 mm. The aperture of the aperture when the sample flowed through the aperture exceeded 1 g was recorded. The measurement was performed three times, and the average value was used as the toner fluidity value.
○: Less than 8 mm ×: 8 mm or more

Claims (5)

An emulsion polymerization step of producing a dispersion containing polymer primary particles by an emulsion polymerization method;
Agglomeration step of agglomerating the polymer primary particles and the colorant to obtain particle agglomerates;
An aging step of fusing the particle aggregates to produce toner mother particles;
An electrostatic charge image developing toner manufacturing method comprising a cooling step of cooling a dispersion of toner base particles, wherein an alkaline electrolyte is added to the dispersion of toner base particles in the cooling step. A method for producing a toner for image development. 2. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein in the cooling step, an alkaline electrolyte is added to the dispersion of the toner base particles, and then an acidic electrolyte is added. 3. The electrostatic charge image developing device according to claim 1, wherein, in the cooling step, the addition start temperature of the alkaline electrolyte is equal to or higher than the glass transition temperature of the binder resin contained in the toner and the melting point of the crystalline substance. Toner manufacturing method. 4. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein, in the cooling step, the addition start temperature of the acidic electrolyte is not higher than the melting point of the crystalline substance contained in the toner. An electrostatic image developing toner obtained by the production method according to claim 1.