JP2006084600A - Electrostatic charge image developing toner, method for manufacturing same and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electrostatic charge image developing magnetic toner which is excellent in various properties such as developing performance, transferability, fixability and cleanability, and to provide a developer and an image forming method. <P>SOLUTION: The electrostatic image developing toner contains a binder resin, magnetic powder and a release agent and has a shape factor of 110-140, wherein the surface of the magnetic powder has been subjected to basic treatment with a metal compound. The developer for developing electrostatic charge image comprises the toner and a carrier. The image forming method uses the toner or developer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrostatic image developing toner used when developing an electrostatic latent image formed by an electrophotographic method, an electrostatic recording method or the like with a developer, a method for producing the same, and the electrostatic image developing toner. The present invention relates to an electrostatic charge image developer contained therein, an image forming method using the electrostatic charge image developer, and a method for mixing and drying an electrostatic charge image developing toner.

  A method for visualizing image information through an electrostatic charge image, such as electrophotography, is currently widely used in various fields. In the electrophotographic method, an electrostatic image is formed on a photoreceptor through a charging step, an exposure step, etc., and the electrostatic image is developed using a developer containing toner particles, and a transfer step, a fixing step, etc. Then, the electrostatic charge image is visualized.

  By the way, as the developer, a two-component developer containing toner particles and carrier particles and a one-component developer containing magnetic toner particles or non-magnetic toner particles are known. The toner particles in the developer are usually produced by a kneading and pulverizing method. In this kneading and pulverization method, a thermoplastic resin or the like is melt-kneaded together with a pigment, a charge control agent, a release agent such as wax, and the like, and after cooling, the melt-kneaded material is finely pulverized and classified to obtain desired toner particles. It is a method of manufacturing. The toner particles produced by the kneading and pulverizing method may be further added with inorganic and / or organic fine particles on the surface as necessary for the purpose of improving fluidity and cleaning properties.

  In the case of toner particles produced by the kneading and pulverization method, the shape thereof is usually indeterminate and the surface composition is not uniform. Although the shape and surface composition of the toner particles slightly change depending on the pulverization properties of the materials used and the conditions of the pulverization process, it is difficult to intentionally control them to a desired level. In particular, in the case of toner particles manufactured by the kneading and pulverizing method using a material having high pulverization properties, the toner particles are further pulverized or the shape thereof is changed by mechanical forces such as various shearing forces in the developing machine. Often happens. As a result, in the two-component developer, finely divided toner particles are fixed to the carrier surface, and the charge deterioration of the developer is accelerated. In the one-component developer, the particle size distribution is expanded, There arises a problem that finely divided toner particles are scattered, and developability is lowered with a change in toner shape, and image quality is deteriorated.

When the shape of the toner particles is indeterminate, the fluidity is not sufficient even when a fluidity aid is added, and the fine particles of the fluidity aid are recessed in the toner particles by mechanical force such as shear force during use. There is a problem that the fluidity is lowered and the fluidity is deteriorated with time, and developability, transferability, cleaning property and the like are deteriorated. Further, when such toner is collected by a cleaning process, returned to the developing machine, and reused, there is a problem that image quality is likely to deteriorate. In order to prevent these problems, it is conceivable to further increase the amount of the fluidity aid. However, in this case, there arises a problem that black spots are generated on the photoconductor and particles of the fluidity aid are scattered.
On the other hand, in the case of a toner in which a release agent such as wax is internally added, the release agent may be exposed on the surface of toner particles depending on the combination with a thermoplastic resin. In particular, in the case of a toner comprising a combination of a resin imparted with elasticity by a high molecular weight component and slightly pulverized resin and a brittle wax such as polyethylene, polyethylene is often exposed on the surface of the toner particles. Although such toner is advantageous for releasability at the time of fixing and cleaning of untransferred toner from the photosensitive member, the polyethylene on the surface of the toner particles is caused by mechanical force such as shearing force in the developing machine. Since the toner particles are detached from the toner particles and easily transferred to a developing roll, a photoreceptor, a carrier, or the like, there is a problem that such contamination easily occurs and reliability as a developer is lowered.

  Under these circumstances, as means for producing a toner whose particle shape and surface composition are intentionally controlled in recent years, there are descriptions in JP-A Nos. 63-2822752 and 6-250439. An emulsion polymerization aggregation method has been proposed. In this emulsion polymerization aggregation method, a resin dispersion is prepared by emulsion polymerization, while a colorant dispersion in which a colorant is dispersed in a solvent is prepared and mixed to form aggregated particles corresponding to the toner particle size. The toner particles are then fused to obtain toner particles. According to this emulsion polymerization aggregation method, the toner shape can be arbitrarily controlled from an indeterminate shape to a spherical shape by selecting the heating temperature condition.

Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439

  In the electrophotographic process, in order to stably maintain and demonstrate the performance of the toner under various mechanical stresses, the exposure of the release agent to the surface of the toner particles can be suppressed, the surface hardness of the toner particles can be increased, It is necessary to further improve the smoothness of the toner particle surface. Further, since the release agent causes various problems when exposed on the surface of the toner particles, it is desirable that the release agent exists in the vicinity of the surface of the toner particles in consideration of the performance of the toner at the time of fixing.

  In recent years, the demand for higher image quality has increased, and in order to realize high-definition images, the tendency to reduce the toner diameter is remarkable. However, even if the particle size distribution of the conventional toner remains as it is, the problem of carrier and photoconductor contamination and toner scattering becomes significant due to the presence of toner on the fine powder side in the particle size distribution. It is difficult to achieve high reliability at the same time. In order to simultaneously achieve high image quality and high reliability, it is necessary to sharpen the toner particle size distribution and reduce the particle size.

  The emulsion polymerization aggregation method is effective for realizing a reduction in toner particle size and shape control. However, magnetic powder particles are difficult to encapsulate because the specific gravity is significantly different from other toner raw materials such as resin particles, and the hardness of the toner particles increases due to the inclusion, or due to the influence of the magnetic powder itself. It was difficult to control the shape or the toner surface smoothness.

An object of the present invention is to solve the conventional problems. That is,
1. An object of the present invention is to provide a magnetic toner for developing an electrostatic image that is excellent in various properties such as developability, transfer property, fixability, and cleanability.
2. An object of the present invention is to provide a highly reliable electrostatic toner for developing an electrostatic image that stably maintains and exhibits the various performances.
3. It is an object of the present invention to provide a method for producing a magnetic toner for developing an electrostatic charge image that can easily and easily produce a toner for developing an electrostatic charge image having excellent characteristics.
4). An object is to provide an electrostatic charge image developer having high transfer efficiency and low toner consumption.
5. An object of the present invention is to provide an image forming method capable of easily and simply forming a high-quality and reliable image.
6). An object is to provide an electrostatic charge image developer and an image forming method capable of obtaining high image quality in a so-called cleaner-less system having no cleaning mechanism.
7). It is an object of the present invention to provide an electrostatic charge image developer and an image forming method which are highly suitable for a so-called toner recycling system in which toner collected from a cleaner is reused and which can obtain high image quality.

The present inventors solved the above problems by adopting the following configurations [1] to [6]. That is, the present invention is as listed below.
[1] An electrostatic charge image developing toner containing a binder resin, magnetic powder, and a release agent, wherein the toner has a shape factor of 110 or more and 140 or less, and the surface of the magnetic powder is a metal compound and basic A toner for developing electrostatic images, characterized by being processed;
[2] In the first dispersion obtained by dispersing at least resin particles, the resin particles, at least one kind of magnetic powder whose surface is basic-treated with a metal compound, and at least one kind of release agent, and / or An agglomeration step of mixing a second dispersion obtained by dispersing other particles to form a dispersion of aggregated particles composed of the resin particles, the magnetic powder, and the release agent, in the aggregated particle dispersion, An adhering step in which a dispersion of at least resin particles is added and mixed to form a dispersion of adhering particles with the resin particles adhering to the agglomerated particles; a resin containing the adhering particle dispersion in the adhering particles For the development of an electrostatic image comprising a fusing step of fusing the adhering particles to form a dispersion of the fusing particles by heating to a temperature above the glass transition temperature of the glass, and a separation and drying step of separating and drying the resulting fused particles Production method of toner;
[3] An electrostatic charge developing developer comprising a carrier and a toner, wherein the toner is the electrostatic charge developing toner of [1];
[4] A step of forming an electrostatic latent image on the electrostatic latent image carrier, a step of developing the electrostatic latent image with a developer on the developer carrier to form a toner image, and a toner image on the transfer body In the image forming method including the step of transferring the toner image, the step of fixing the toner image on the transfer member, and the cleaning step of removing the toner remaining on the electrostatic latent image carrier, the developer [1 An electrostatic charge developing toner according to [3], or an electrostatic charge developing developer according to [3] above;
[5] Mixing / drying of electrostatic charge image developing toner using a mixing / drying apparatus provided with a stirring means in the mixing / drying chamber to attach and fix external additives to the toner particles and dry (secondary drying) In the method, the total amount (flow velocity) F [m ³ / h] of the sealing gas for the stirring unit rotating shaft and / or the gas injected from the separately provided gas supply port is the amount of toner charged into the mixing / drying device. A method for mixing and drying an electrostatic charge image developing toner, wherein [kg] is adjusted to satisfy 0.3 ≦ F / W ≦ 1.5.

  According to the present invention, various problems in the prior art can be solved. That is, according to the present invention, there is provided a magnetic toner for developing an electrostatic charge image that is excellent in various properties such as developability, transfer property, fixability, and cleaning property, and that stably maintains and exhibits the above performances. can do. In addition, according to the present invention, it is possible to provide a method for producing a magnetic toner for developing an electrostatic charge image that can easily and easily produce a toner for developing an electrostatic charge image having excellent characteristics. In addition, according to the present invention, it is possible to provide an electrostatic charge image developer having high transfer efficiency and low toner consumption. Further, according to the present invention, it is possible to provide an image forming method capable of easily and simply forming an image with high image quality and high reliability. The electrostatic charge image developer and the image forming method of the present invention are highly suitable not only in a cleanerless system but also in a toner recycling system, and can easily obtain high image quality.

Further, according to the method for mixing and drying an electrostatic image developing magnetic toner of the present invention, in the mixing and drying step of the external additive in the fixed mixing tank following the drying step for obtaining the powdered toner, a predetermined amount By performing the mixing process while injecting the low-humidity gas, secondary drying can be performed together with the adhesion / fixation of the external additive. As a result, it is possible to obtain a good quality toner with a uniform external additive concentration, with moisture removed, and free from agglomerated particles due to non-drying.
This also eliminates the need for equipment related to preliminary drying and secondary drying. In addition, even if the moisture content of the water-containing toner cake as a raw material fluctuates, the supply amount of the drying process can be set on a dry product basis, so that the production operation can be performed without breaking the processing balance between the preceding and following processes.
Furthermore, the magnetic toner with the external additive attached / fixed and dried by cooling to remove the heat generated during mixing without causing condensation on the wall surface in the mixing / drying device. Particles can be recovered with good yield.

Hereinafter, the present invention will be described in more detail.
<Method for producing toner for developing electrostatic image>
The method for producing an electrostatic charge image developing toner of the present invention includes the following first step, second step and third step.

(First step)
The first step is a step of preparing an aggregated particle dispersion by forming aggregated particles by heating to a temperature equal to or lower than the glass transition point of the resin particles in a dispersion obtained by dispersing resin particles (hereinafter referred to as “aggregated particle dispersion”). The first step may be referred to as “aggregation step”).
The dispersion is obtained by dispersing at least resin particles. The resin particles are resin particles. Examples of the resin include thermoplastic binder resins. Specifically, homopolymers or copolymers (styrene-based resins) of styrenes such as styrene, parachlorostyrene, and α-methylstyrene; acrylic Methyl acid, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, methacrylic acid 2 -Homopolymers or copolymers of vinyl group esters such as ethylhexyl (vinyl resins); Homopolymers or copolymers of vinyl nitriles such as acrylonitrile and methacrylonitrile (vinyl resins); A single vinyl ether such as ether or vinyl isobutyl ether Polymer or copolymer (vinyl resin); homopolymer or copolymer of vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone (vinyl resin); ethylene, propylene, butadiene, isoprene, etc. Homopolymers or copolymers of olefins (olefin resins); non-vinyl condensation resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins, and these non-vinyl condensation resins And a graft polymer of a vinyl monomer and the like. These resins may be used alone or in combination of two or more.
Among these resins, styrene resins, vinyl resins, polyester resins, and olefin resins are preferable. Copolymers of styrene and n-butyl acrylate, n-butyl acrylate, bisphenol A / fumaric acid copolymer. Particularly preferred is a copolymer of styrene and olefin.

  As an average particle diameter of the said resin particle, it is 1 micrometer or less normally, and it is preferable that it is 0.01-1 micrometer. When the average particle size exceeds 1 μm, the particle size distribution of the finally obtained electrostatic image developing toner is broadened or free particles are generated, which tends to deteriorate performance and reliability. On the other hand, when the average particle size is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toners is improved, and the variation in performance and reliability is advantageous. The average particle diameter in the previous period can be measured using, for example, a Coulter counter.

  Examples of the magnetic powder used in the present invention include magnetic materials such as metals, alloys such as ferrite, magnetite, reduced iron, cobalt, nickel, manganese, and compounds containing these metals, and particularly magnetite is preferable. It is obtained by a known production method. The shape of the magnetic powder includes octahedrons, hexahedrons, spheres, needles, scales, etc., but a shape closer to a sphere is preferable.

  Further, the magnetic powder needs to be subjected to a basic treatment with a metal compound. Here, the basic treatment with a metal compound is to make the polarity basic by covering at least a part of the surface of the magnetic powder with a metal. By making the polarity basic, inclusion of the magnetic powder in the toner can be improved. The reason for this is presumably that organic compound particles are likely to become anionic in water, so that the basic properties of the magnetic powder improve the cationic property and facilitate aggregation. Examples of the metal element covering the surface include Al, Mg, Ca and the like, and Al is preferable. The amount of the metal compound used for the surface treatment is preferably 0.3 to 2.0% by weight of the magnetic powder in terms of metal element. If the treatment amount is less than 0.3% by weight, the basic performance of the magnetic powder fine particles is lowered and it is difficult to achieve the object of the present invention. On the other hand, even if the treatment amount exceeds 2.0% by weight, the basic performance is not improved, the treatment becomes difficult, and it is not economical.

  The volume average particle size of the magnetic powder particles used in the present invention is preferably in the range of 50 to 500 nm. When the volume average particle diameter is less than 50 nm, the aggregated toner particles become hard, and the shape controllability of the toner is deteriorated in the fusion process described later. On the other hand, when the volume average particle diameter exceeds 500 nm, the content of magnetic powder particles in the toner is reduced, so that sufficient blackness cannot be obtained. The content of the magnetic powder fine particles in the toner is preferably in the range of 6 to 50% by weight. When the content is less than 6% by weight, sufficient blackness cannot be obtained, and when the content exceeds 50% by weight, the toner cannot be surely encapsulated, and a part of the toner is exposed on the surface. Since the shape controllability is deteriorated, the toner is broadly charged, causing fogging and scattering. The magnetic powder content in the toner differs depending on whether the toner is used as a one-component developer or a two-component developer in combination with a carrier. The amount of magnetic powder in the toner can be reduced.

  Examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones having a softening point by heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide; Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; minerals such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, and Fischer-Tropsch wax Petroleum wax; and modified products thereof.

These waxes are dispersed in water together with a polymer electrolyte such as an ionic surfactant, polymer acid, polymer base, etc., heated above the melting point, and can be applied with a strong shearing force or pressure discharge type. When processed using a disperser, it can be easily made into fine particles of 1 μm or less.
In the present invention, other components such as a colorant, a charge control agent, inorganic particles, a lubricant, and an abrasive may be dispersed according to the purpose. In this case, other particles may be dispersed in a dispersion obtained by dispersing resin particles, or a dispersion obtained by dispersing other particles is mixed in a dispersion obtained by dispersing resin particles. May be.

  Examples of the colorant include pigments and dyes such as carbon black, aniline black, furnace black, and perylene black. These colorants may be used alone or in combination of two or more.

Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments. In addition, as the charge control agent in the present invention, a material that is difficult to dissolve in water is preferable in terms of controlling ionic strength that affects stability during aggregation and fusion and reducing wastewater contamination.
Examples of the inorganic particles include all particles usually used as external additives on the toner surface, such as silica, alumina, titania, calcium carbonate, magnesium carbonate, calcium phosphate, and cerium oxide.
Examples of the lubricant include fatty acid amides such as ethylene bisstearamide and oleic acid amide, and fatty acid metal salts such as zinc stearate and calcium stearate.
Examples of the abrasive include the aforementioned silica, alumina, cerium oxide, and the like.

The volume average particle size of the other components is usually 1 μm or less, preferably 0.01 to 1 μm. When the volume average particle size exceeds 1 μm, the finally obtained electrostatic charge image developing toner has a broad volume particle size distribution and the generation of free particles, which tends to deteriorate performance and reliability. On the other hand, when the volume average particle size is within the above range, there are no disadvantages, and it is advantageous in that uneven distribution among toners is reduced, dispersion in the toner is improved, and variations in performance and reliability are reduced. . The volume average particle diameter can be measured using, for example, a Coulter counter.
Examples of the dispersion medium in the dispersion include an aqueous medium. Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together. In the present invention, it is preferable to add and mix a surfactant in the aqueous medium. Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene Nonionic surfactants such as glycols, alkylphenol ethylene oxide adducts, polyhydric alcohols and the like can be mentioned. Among these, anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together. Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable.

  The content of the resin particles in the dispersion may be 40% by weight or less, and preferably about 2 to 20% by weight in the aggregated particle dispersion when the aggregated particles are formed. In addition, the content of the magnetic powder in the magnetic powder dispersion may be 50% by weight or less in the aggregated particle dispersion when the aggregated particles are formed, and is about 2 to 40% by weight. Is preferred.

  Furthermore, when the other components are also dispersed in the dispersion, the content of the other components in the dispersion may be a level that does not hinder the object of the present invention, and is generally very small. In the aggregated particle dispersion when the aggregated particles are formed, it is about 0.01 to 5% by weight, preferably about 0.5 to 2% by weight. If the content is outside the above range, the effect of dispersing the other particles may not be sufficient, or the particle size distribution may be widened and the characteristics may deteriorate.

  The dispersion obtained by dispersing at least the resin particles is prepared as follows, for example. When the resin in the resin particles is a homopolymer or copolymer (vinyl resin) of a vinyl monomer such as the ester having a vinyl group, the vinyl nitrile, the vinyl ether, or the vinyl ketone. The resin monomer particles made of a vinyl monomer homopolymer or copolymer (vinyl resin) are obtained by emulsion polymerization or seed polymerization of the vinyl monomer in an ionic surfactant. A dispersion obtained by dispersing in an ionic surfactant is obtained. When the resin in the resin particles is a resin other than the vinyl monomer, if the resin is dissolved in an oily solvent having a relatively low solubility in water, the resin is used as the oily solvent. Dissolve this solution, disperse the fine particles in water together with the ionic surfactant and polymer electrolyte using a disperser such as a homogenizer, and then heat or reduce the pressure to evaporate the oily solvent. A dispersion obtained by dispersing resin particles made of a resin other than the above in an ionic surfactant is obtained.

  The dispersion means is not particularly limited, and examples thereof include known dispersion apparatuses such as a rotary shear type homogenizer and a ball mill having a media, a sand mill, and a dyno mill.

The agglomerated particles are prepared as follows, for example.
In a first dispersion obtained by dispersing at least the resin particles in an aqueous medium to which an ionic surfactant is added and mixed, an ionic surfactant (1) having a polarity opposite to that of the ionic surfactant, or The aqueous medium (2) added and mixed or the second dispersion (3) containing the aqueous medium is mixed. When this mixed liquid is stirred, the resin particles and the like are aggregated in the dispersion by the action of the ionic surfactant, and aggregated particles are formed by the resin particles and the aggregated particle dispersion is prepared. The mixing is performed at a temperature below the glass transition point of the resin of the resin particles contained in the mixed solution. By performing the mixing under this temperature condition, the aggregation can be performed in a stable state. The second dispersion is a dispersion obtained by dispersing the resin particles, the magnetic powder, the release agent and / or the other particles. Moreover, the said stirring can be performed using a well-known stirring apparatus, a homogenizer, a mixer etc., for example.

  In the case of (1) or (2), agglomerated particles are formed by agglomerating resin particles dispersed in the first dispersion. At this time, the content of the resin particles in the first dispersion is usually 5 to 60% by weight, and preferably 10 to 40% by weight. Further, the content of the aggregated particles in the aggregated particle dispersion when the aggregated particles are formed is usually 40% by weight or less.

In the case of (3), when the particles dispersed in the second dispersion are the resin particles, the resin particles and the resin particles dispersed in the first dispersion are aggregated. Agglomerated particles are formed. On the other hand, when the particles dispersed in the second dispersion are the magnetic powder and / or the other particles, these and the resin particles dispersed in the first dispersion are heteroaggregated. Aggregated particles are formed. Further, when the particles dispersed in the second dispersion are the resin particles, the magnetic powder, and / or the other particles, these and the resin dispersed in the first dispersion Aggregated particles formed by aggregation with the particles are formed. At this time, the content of the resin particles in the first dispersion is usually 5 to 60% by weight, preferably 10 to 40% by weight, and the resin particles in the second dispersion, the colorant, and The content of the other particles is usually 5 to 60% by weight, preferably 10 to 40% by weight. When the content is outside the above range, the particle size distribution may be widened and the characteristics may be deteriorated. Further, the content of the aggregated particles in the aggregated particle dispersion when the aggregated particles are formed is usually 40% by weight or less. When forming the agglomerated particles and the adhered particles, the ionic surfactant contained in the added dispersion and the ionic surfactant contained in the added side are made to have opposite polarities. It is preferable to change the balance of the polarity.
The average particle size of the formed aggregated particles is not particularly limited, but is usually controlled to be approximately the same as the volume average particle size of the electrostatic image developing toner to be obtained. The control can be easily performed, for example, by appropriately setting and changing the temperature and the stirring and mixing conditions. Through the above first step, aggregated particles having an average particle size substantially the same as the average particle size of the electrostatic image developing toner are formed, and an aggregated particle dispersion liquid in which the aggregated particles are dispersed is prepared. In the present invention, the aggregated particles may be referred to as “mother particles”.

(Second step)
The second step is a step of adding and mixing a fine particle dispersion in which fine particles are dispersed in the aggregated particle dispersion to form the adhered particles by attaching the fine particles to the aggregated particles (hereinafter referred to as the first step). Two steps may be referred to as “attachment step”).

  Examples of the fine particles include resin-containing fine particles, inorganic fine particles, magnetic powder fine particles, release agent fine particles, colorant fine particles, internal additive fine particles, and charge control agent fine particles.

  The resin-containing fine particles are fine particles containing at least one of the above-described resins. The resin-containing fine particles may be resin fine particles containing 100% by weight of at least one of the above-described resins, or at least one of the above-described resins, the above-described magnetic powder, a release agent, and a colorant. Further, it may be a composite fine particle containing at least one of inorganic particles, an internal additive and a charge control agent. In the present invention, as will be described later, this adhesion step can be performed a plurality of times, and it is necessary to finally control the amount of magnetic powder on the surface of the toner.

When the inorganic fine particles are used and adhered to the aggregated particles, a toner for developing an electrostatic charge image having a structure encapsulated with a layer of the inorganic fine particles can be produced after the fusion in the third step.
The volume average particle size of the fine particles is usually 1 μm or less, preferably 0.01 to 1 μm. When the volume average particle size exceeds 1 μm, the particle size distribution of the finally obtained electrostatic image developing toner is broadened or free particles are generated, which tends to deteriorate performance and reliability. On the other hand, when the volume average particle diameter is in the above range, there are no disadvantages and it is advantageous in that a layer structure of fine particles is formed. The volume average particle diameter can be measured using, for example, a Coulter counter.

  The volume of the fine particles is preferably 50% or less of the volume of the obtained electrostatic charge image developing toner, depending on the volume fraction of the obtained electrostatic charge image developing toner. When the volume of the fine particles exceeds 50% of the obtained electrostatic charge image developing toner volume, the fine particles do not adhere to or aggregate with the aggregated particles, and new aggregated particles are formed by the fine particles. Variations in the composition distribution and particle size distribution of the toner for developing an electrostatic image may become significant, and desired performance may not be obtained.

In the fine particle dispersion, these fine particles may be dispersed singly or in combination of two or more. In the latter case, the combination of fine particles to be used is not particularly limited and can be appropriately selected depending on the purpose.
Examples of the dispersion medium in the fine particle dispersion include the above-described aqueous medium. In the present invention, it is preferable to add and mix at least one of the aforementioned surfactants in the aqueous medium.

  The content of the fine particles in the fine particle dispersion is usually 5 to 60% by weight, preferably 10 to 40% by weight. When the content is outside the above range, the structure and composition of the electrostatic charge image developing toner from the inside to the surface may not be sufficiently controlled. Further, the content of the aggregated particles in the aggregated particle dispersion when the aggregated particles are formed is usually 40% by weight or less.

The fine particle dispersion is prepared, for example, by dispersing the fine particles in an aqueous medium to which an ionic surfactant or the like is added and mixed. Further, it is prepared by mechanically shearing or electrically adsorbing and fixing to the latex surface prepared by emulsion polymerization or seed polymerization.
In the second step, the fine particle dispersion is added to and mixed with the aggregated particle dispersion prepared in the first step, and the fine particles are adhered to the aggregated particles to form adhered particles. Since the fine particles correspond to newly added particles as seen from the aggregated particles, they may be referred to as “added particles” in the present invention.

  There is no restriction | limiting in particular as the method of the said addition mixing, For example, you may carry out gradually continuously and may carry out in steps divided | segmented into multiple times. Thus, by adding and mixing the fine particles (additional particles), the generation of fine particles can be suppressed, and the particle size distribution of the resulting electrostatic image developing toner can be sharpened. If the addition and mixing are performed in stages divided into a plurality of times, a layer of the fine particles is layered stepwise on the surface of the aggregated particles, and the structural change or the like from the inside to the outside of the electrostatic image toner particles A composition gradient can be provided, particle surface uniformity and shape controllability can be improved, and particle size distribution can be maintained and fluctuations can be suppressed during fusion in the third step. At the same time, the addition of surfactants and stabilizers such as bases or acids to increase stability during fusion can be made unnecessary, and the amount of those added can be minimized, reducing costs and improving quality. Is advantageous in that it becomes possible.

  Conditions for attaching the fine particles to the aggregated particles are as follows. That is, the temperature is a temperature below the glass transition point of the resin of the resin particles in the first step, and preferably about room temperature. When heated at a temperature below the glass transition point, the aggregated particles and the fine particles are likely to adhere, and as a result, the formed attached particles are likely to be stable. The treatment time depends on the temperature and cannot be specified unconditionally, but is usually about 5 minutes to 2 hours. In addition, at the time of the adhesion, the dispersion liquid containing the aggregated particles and the fine particles may be allowed to stand or may be gently stirred by a mixer or the like. The latter case is advantageous in that uniform adhered particles are easily formed.

  In the present invention, the number of times that the second step is performed may be one or a plurality of times. In the former case, only one layer of the fine particles (additional particles) is formed on the surface of the aggregated particles, whereas in the latter case, two layers of the fine particles (additional particles) are formed on the surface of the aggregated particles. These are sequentially formed. Therefore, the latter case is advantageous in that a toner for developing an electrostatic charge image having a complicated and precise hierarchical structure can be obtained, and a desired function can be imparted to the toner for developing an electrostatic charge image.

  In the case where the second step is performed a plurality of times, the first fine particles to be adhered to the aggregated particles and the fine particles to be subsequently adhered may be in any combination, and the use and purpose of the electrostatic image developing toner It can be appropriately selected according to the like.

  In the case of the combination in which the release agent fine particles and the resin-containing fine particles are adhered in this order, the resin-containing fine particle layer exists on the outermost surface of the electrostatic charge image developing toner particles. The toner is not exposed on the particle surface of the toner for developing an electrostatic image, but is present in the vicinity of the particle surface. For this reason, it is possible to effectively act the release agent fine particles at the time of fixing while suppressing the exposure of the release agent fine particles. In the case of the combination in which the colorant fine particles and the resin-containing fine particles are adhered in this order, the resin-containing fine particle layer is present on the outermost surface of the electrostatic charge image developing toner particles. The toner is not exposed on the particle surface of the toner for developing a charge image and is present in the vicinity of the particle surface. For this reason, the colorant fine particles are prevented from falling off from the surface of the particles.

  In the case of the combination in which the resin-containing fine particles and the inorganic fine particles are adhered in this order, a layer made of inorganic fine particles exists on the outermost surface of the electrostatic charge image developing toner particles. An electrostatic charge image developing toner having a structure is produced. As a combination other than the above, for example, when a combination in which a release agent particle dispersion and a resin-containing fine particle or inorganic fine particle having high hardness are adhered in this order is employed, a hard surface is formed on the outermost surface of the electrostatic image developing toner. A shell can be formed.

When the second step is performed a plurality of times, each time the fine particles are added and mixed, the dispersion containing the fine particles and the aggregated particles is heated at a temperature equal to or lower than the glass transition point of the resin of the resin particles in the first step. An embodiment in which the heating temperature is increased stepwise is more preferable. This is advantageous in that the generation of free particles can be suppressed.
By the above second step, attached particles are formed by adhering the fine particles to the aggregated particles prepared in the first step. In addition, when the second step is performed a plurality of times, attached particles are formed by adhering the fine particles a plurality of times to the aggregated particles prepared in the first step. Therefore, in the second step, an electrostatic image developing toner having desired characteristics can be freely designed and manufactured by attaching appropriately selected fine particles to the aggregated particles.

(Third step)
The third step is a step of fusing the attached particles by heating (hereinafter, the third step may be referred to as a “fusion step”).
The heating temperature may be from the glass transition temperature of the resin contained in the adhered particles to the decomposition temperature of the resin. Therefore, the temperature of the heating varies depending on the type of resin of the resin particles and cannot be generally defined, but is generally a glass transition temperature of the resin contained in the adhered particles to 180 ° C. In addition, the said heating can be performed using a publicly known heating apparatus and instrument. As the fusion time, a short time is sufficient if the heating temperature is high, and a long time is required if the heating temperature is low. That is, the fusion time depends on the temperature of the heating and cannot be defined in general, but is generally 30 minutes to 10 hours. The electrostatic image developing toner obtained after completion of the third step can be further washed and dried under appropriate conditions.
Further, as a subsequent step of the third step, inorganic particles such as silica, alumina, titania, calcium carbonate, vinyl resin, polyester, and the like are formed on the surface of the obtained toner for developing an electrostatic image (after primary drying). Resin particles such as resin and silicone resin, so-called external additives, may be added in a dry state while applying a shearing force. These external additives have functions such as fluidity aids and cleaning aids. A mixing / drying apparatus and method suitable for attaching and fixing the external additive to the toner will be described later.

  By the above third step, the adhered particles prepared in the second step are fused while the fine particles (additional particles) remain adhered to the surface of the aggregated particles (mother particles), and the electrostatic image developing toner. Is manufactured.

<Toner for electrostatic image development>
The electrostatic image developing toner of the present invention is produced by the method for producing an electrostatic image developing toner of the present invention. The toner for developing an electrostatic charge image has a structure in which the aggregated particles are used as core particles and the fine particle layer is coated on the surface thereof. The fine particle layer may be one layer or two or more layers, and the number thereof is the same as the number of times of performing the second step in the method for producing an electrostatic charge image developing toner of the present invention. It is.

The volume average particle diameter of the electrostatic image developing toner is preferably 2 to 9 μm, more preferably 3 to 8 μm. If the average particle size is less than 2 μm, the chargeability tends to be insufficient and the developability may be deteriorated. If the average particle size exceeds 9 μm, not only the shape factor of the toner cannot be controlled but also image resolution. May decrease. As the particle size distribution, volume GSD (volume GSD = (volume D84 / volume D16) ^0.5 ) or number GSD (number GSD = (number D84 / number D16) ^0.5 , using cumulative distribution D16 and D84 as an index thereof. ) Can be used simply. The volume GSD is preferably 1.30 or less, and more preferably 1.27 or less. If the volume GSD exceeds 1.30, developability may deteriorate over time due to selective development or the like. Further, the toner of the present invention has a shape factor (SF1) of 100 to 140, preferably 100 to 130, more preferably 100 to 125. SF1 is a value calculated by the following mathematical formula 1.
Formula 1: SF1 = {(ML) ² / A} × (π / 4) × 100
Here, ML represents the maximum length of the toner particles, and A represents the projected area of the toner particles. As ML and A, values obtained by digitizing toner optical microscope and electron microscope images by image analysis using an image analyzer can be used.

  The charge amount of the toner of the present invention is preferably in the range of 20 to 40 μC / g in absolute value. If the charge amount is less than 20 μC / g, background stains are likely to occur, and if it exceeds 40 μC / g, the image density tends to be lowered. A more preferable range of the charge amount is 25 to 35 μC / g. The ratio of the charge amount in the summer (high temperature and high humidity) environment of the toner of the present invention to the charge amount in the winter (low temperature and low humidity) environment is preferably in the range of 0.5 to 1.5. Outside this range, the dependence of the charge amount on the environment becomes strong, and charging stability is lacking, which is not preferable for practical use. A more preferable range of the charge amount ratio is 0.7 to 1.3.

<Electrostatic image developer>
The electrostatic image developing toner of the present invention can exhibit sufficient performance as a magnetic one-component toner, but can also be used as a two-component developer. The electrostatic image developer of the present invention comprises the electrostatic image developing toner of the present invention and a carrier. The carrier is not particularly limited, and examples thereof include known carriers. For example, carriers described in JP-A Nos. 62-39879 and 56-11461 can be used. . The mixing ratio of the electrostatic image developing toner of the present invention and the carrier in the electrostatic image developer is not particularly limited and may be appropriately selected depending on the intended purpose.

<Image forming method>
The image forming method of the present invention includes an electrostatic latent image forming step, a toner image forming step, and a transfer step. Each of the above steps is a general step per se, and is described in, for example, JP-A-56-40868 and JP-A-49-91231. The image forming method of the present invention can be carried out using an image forming apparatus such as a copier or a facsimile machine known per se.
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the electrostatic latent image carrier. The toner image forming step is a step of developing the electrostatic latent image to form a toner image. The transfer step is a step of transferring the toner image onto a transfer body. In the image forming method of the present invention, an aspect further including a cleaning step and a recycling step is preferable. The cleaning step is a step of collecting excess electrostatic charge image developing toner when forming a toner image. The recycling step is a step of transferring the electrostatic image developing toner collected in the cleaning step to the developer layer. The image forming method including the cleaning process and the recycling process can be performed using an image forming apparatus such as a toner recycling system type copying machine or facsimile machine. The present invention can also be applied to a recycling system in which the cleaning process is omitted and toner is collected simultaneously with development.

<External additive mixing / drying method and apparatus used therefor>
Next, a mixing / drying apparatus and method suitable for attaching and fixing the external additive to the obtained toner will be described.
As described above, an external additive having functions such as a fluidity aid and a cleaning aid can be adhered and fixed to the toner. An example of a mixing / drying apparatus suitable for attaching, fixing, and drying external additives is shown in FIG. 1 (schematic front view). In the figure, reference numeral 10 denotes a mixing / drying apparatus main body, which is configured such that rotating blades 11 and 12 provided at the center of the mixing / drying chamber 16 are rotated by driving of a motor 13. Further, in order to remove heat generated by the mixing process, the mixing / drying chamber 16 is covered with a jacket 14 and a cooling refrigerant is supplied therein.
The toner particles and the external additive obtained through the air dryer are put into the mixing / drying chamber 16 from the raw material supply port 15, pressed against the walls of the mixing / drying chamber by the rotational force of the rotary blades 11, 12 and swirled. , Mixed by the tip of the rotary blade. Further, the film is once peeled off and dispersed from the wall surface by a deflector provided in the mixing / drying chamber, and again pressed against the mixing / drying chamber wall to be swirled and mixed, and stable mixing is performed by repeating this operation. Further, when mixing processing (attachment and fixation of external additives) is performed in the mixing / drying chamber, the flow rate is adjusted while looking at the flow meter 18 (rotary blade). Drying is performed by injecting a drying gas whose flow rate is adjusted while looking at the flow meter 20 from the piping 17 or from a drying gas inlet (nozzle) 19 attached to the lid of the mixing / drying chamber 16. In addition, both of the above may be sufficient as injection | pouring of the gas for drying. Further, although the number of nozzles attached to the lid of the mixing / drying chamber 16 is one in FIG. 1, it is not limited, and a plurality of nozzles may be provided depending on the flow rate used for drying.

When the flow rate (total flow rate) of the drying gas supplied to the mixing / drying apparatus is F [m ³ / h (converted to atmospheric pressure)] and the toner input amount is W [kg], the mixing / drying in the present invention is performed. In the method, drying (secondary drying) is performed simultaneously with the mixing treatment in the range of 0.3 ≦ F / W ≦ 1.5. When F / W is less than 0.3, drying performed simultaneously with the mixing process is insufficient. When F / W is greater than 1.5, drying is sufficient, but a large amount of gas is used. After that, the scale (capacity) of the mixing / drying apparatus becomes large and becomes unrealistic. The gas injection may be performed continuously or intermittently during the mixing process as long as the required dryness (water content) of the toner can be obtained.
The gas used for drying is not limited, and generally air, N ₂ gas or the like can be used. Of these, air is preferable because it is inexpensive and does not require replenishment. In order to promote drying, it is desirable to have a low humidity, and compressed air from a compressor that has been dehumidified to have a dew point of 10 ° C. or lower (preferably 0 ° C. or lower) is used.

While the mixing process and the drying process are performed simultaneously, the injected gas must be discharged from the mixing / drying apparatus, but at this time, neither toner particles nor external additives are discharged. In FIG. 1, a filter 21 is provided on the upper part of the mixing / drying apparatus, and exhausted through a fan 22 via a pipe and a preliminary filter. The degree of exhaust can be adjusted by a valve provided in front of the fan. Some of the toner particles and external additives are captured by the preliminary filter and the filter 21, and can be backwashed off by so-called pulsed air that blows out the instrument air 23. This prevents toner particles and external additives from adhering to and accumulating on the preliminary filter and filter 21, and also prevents loss.
If the jacket is cooled when toner particles and external additives are not added or when they are not mixed, condensation occurs on the inner wall of the mixing / drying device, and the toner particles and external additives adhere to them. In some cases, the toner having the external additive fixed thereon cannot be obtained as desired. In such cases, stop supplying toner particles or external additives to the mixing tank, or provide a bypass channel in the coolant channel and switch to the bypass channel (the jacket is not cooled). Is preferred.
According to the method for mixing and drying the electrostatic image developing toner described above, drying (secondary drying) can be performed in conjunction with the attachment / fixation of the external additive, and moisture is removed and undried. Therefore, it is possible to obtain a good quality toner free of aggregated particles.

Next, a slurry sieving device (or a slurry sieving method) that can be suitably used when aligning the particle size of the electrostatic image developing toner obtained in the present invention will be described. If this slurry sieving device (or slurry sieving method) is used, it is difficult to industrially use, and the coarse powder that causes a reduction in product image quality can be efficiently and stably removed.
First, an example of a conventional general vibration sieve is shown in FIG. 2, and a vibration motor built in the vibration sieve is shown in FIGS. As shown in FIG. 2, a cylindrical sieve frame 104 supported by a plurality of coil springs 102 (having a function of absorbing vibration shake of the vibrating sieve) is provided on the base frame 100, and A conical or sloped bottom surface 106 indicated by a broken line is formed inside. Further, an annular support frame 110 on which a sieve screen 108 is stretched is fixed to the sieve frame 104. Further, a vibration motor (not shown in FIG. 2) is built in the base frame 100, and the entire sieve frame on the coil spring 102 can be vibrated by the operation of the vibration motor. Under the bottom surface 106, a rotatable shaft (not shown) connected to a vibration motor is incorporated, and upper and lower unbalance weights with the center of gravity shifted from the center of the shaft are installed at the upper and lower ends of the shaft. (See FIG. 4).

As shown in FIGS. 3 and 4, the output shaft 204 of the vibration motor 130 has a circular weight mounting plate 134 having an arcuate hole 132 and an arbitrary angle (weight phase angle) with respect to the output shaft 204. A weight 138 fixed by a weight fixing bolt 136 that passes through the arcuate hole 132 for fixing, and a replenishment weight 142 that is detachably fixed to the weight 138 by the weight fixing bolt 140 are provided. Although not shown, an upper weight having a center of gravity eccentric to the shaft is also fixed to a rotatable shaft (shaft) above the vibration motor. The vibration behavior can be changed by changing the phase angle of the weight.
The powder contact surface in the apparatus is preferably coated by buffing or composite plating. The fine particles contained in the composite plating film are particularly preferably fine particles of a fluorine-containing compound having excellent properties such as self-lubricity, low friction, water repellency, oil repellency and non-adhesiveness. Although a fluorine-containing compound can be suitably selected according to the objective, For example, a fluorinated graphite, a fluororesin, fluoride pitch, etc. can use it conveniently.

Using this vibrating sieve, the toner slurry on the sieve mesh 108 can be controlled to collect at the center of the sieve mesh 108, or conversely, to collect at the outer peripheral side.
When the weight phase angle θw (FIG. 4) in the vibration motor 130 is 0 degree, the material on the sieve mesh 108 moves in a straight line from the center of the sieve mesh 108 toward the outside. Further, as the weight phase angle θw is increased, a rotational component is given to the movement of the material on the sieve screen 108. When the weight phase angle θw exceeds approximately 40 degrees, the material on the sieve mesh 108 flows from the outside of the sieve mesh 108 toward the center. Therefore, in the embodiment (FIG. 2) in which the coarse powder discharge port 120 is provided on the outer peripheral surface of the upper frame 105 (FIG. 2), the phase angle of the vibration motor 130 is preferably set to about 0 to 40 degrees. . Then, the toner slurry on the sieve mesh 108 flows toward the center of the sieve mesh 108. However, when the phase angle exceeds 60 degrees, the toner slurry to be sieved does not pass through the portion near the outer periphery of the mesh surface, and sieving using the entire mesh becomes difficult. May occur.

As shown in FIG. 4, the lower unbalance weight can change the weight (weight) 138 weight and the replenishment weight 142 and its weight phase angle θ _W, and by adjusting the weight and angle, The vibration behavior, in particular the amplitude, can be adjusted. Further, the vibration frequency at the time of sieving can be adjusted by the rotation of the vibration motor 130.
In addition to the type directly connected to the shaft as shown in FIG. 3, the vibration motor 130 includes a type that indirectly applies a driving force with a belt. For example, in the vibration sieve as shown in FIG. 2, the vibration frequency can be adjusted by changing the power supply frequency of the vibration motor. In the case of belt driving, the vibration frequency can be changed by changing the ratio of the pulley that drives the belt. Can be adjusted.
Further, by changing the weight weights above and below the rotatable shaft described above, it is possible to adjust the amplitude in the horizontal and vertical directions, respectively. In addition, the amplitude of the mesh frame can be measured by attaching a general scale for measuring amplitude to the mesh frame portion p and visually checking it during vibration. To measure with higher accuracy, connect an appropriate jig. However, it can be measured by connecting a general vibrometer with a suitable measurement range to the jig.

Next, the sieving operation using the vibrating sieve will be described with reference to FIG.
In the circular vibrating screen, as described above, the rotational speed of the vibration motor 130 and the weight and phase angle of the unbalance weight are adjusted to the desired amplitude and frequency, and then the particles are dispersed from the supply port 118 into the apparatus. A liquid (eg, toner slurry) is supplied. The supplied particle dispersion is screened by the three-dimensional vibration of the entire vibration sieve by the operation of the vibration motor, the coarse powder is discharged from the coarse powder outlet 120, and the fine powder passes through the sieve frame 108 and slides on the bottom face 106. Then, it is discharged from the sieve product collection port 116. Thus, a toner slurry having a desired particle size can be obtained in the sieve frame 104.
The material of the liquid contact surface inside the vibration sieve may be stainless steel, buffed or electrolytically polished, or Teflon (registered trademark) coated, plated, or glass-lined.
As the screen mesh, a mesh of a general weaving method such as a twill weave, a plain weave, or a ton cap weave can be used. Depending on the case, a net obtained by calendering these may be used, or a slit-like net such as a wedge wire screen may be used.
As a method for supplying the particle dispersion (for example, toner slurry) to the vibrating sieve, there are methods such as continuous, intermittent, and pulsating. As a pump used for transfer, a general pump such as a centrifugal pump, a diaphragm pump, a plunger pump, a centrifugal pump, a gear pump, a rotary pump, a tube pump, a hose pump, or the like can be used.

  In FIG. 5, the schematic block diagram of the whole slurry sieving apparatus which comprises a general vibration sieve is shown. The toner slurry supplied from the supply port 118 passes through a screen attached to the mesh frame 108, is discharged from the sieving product collection port 116 through the slurry discharge hose 301, and enters the slurry receiving tank 303 from the slurry receiving port 302. A foam recovery pipe 310 including a micro pressure gauge 304 is attached to the upper part of the slurry receiving tank 303, and is connected to the foam recovery tank 306 via the ejector 305. The exhaust gas from the foam recovery tank 306 is sucked by the exhaust gas fan 308 and deodorized in the scrubber 307 by the liquid ejected by the scrubber pump 309. Here, the foam generated in the slurry receiving tank 303 is guided to the foam recovery pipe 310 by the fine negative pressure created by the ejector 305 and recovered in the foam recovery tank 306. The slurry sieving apparatus can perform stable sieving without generating bubbles in the apparatus. In addition, it is also effective to use a vacuum pump or the like as a means for making the inside of the bubble recovery pipe 310 a slight negative pressure. Moreover, by dropping the antifoaming agent from the upper part of the foam recovery pipe 310, the volume of the foam recovery tank 306 can be reduced, and the apparatus can be downsized.

Further, as shown in FIG. 5, a gap is provided between the slurry discharge hose 301 and the slurry inlet 302 and the lower part of the screen is not opened to the atmosphere, but the slurry outlet hose 301 and the slurry inlet 302 are connected to eliminate the gap. Thus, it is possible to make the lower part of the screen have a slight negative pressure. Furthermore, it is possible to connect a plurality of vibrating sieves by providing a plurality of slurry receiving ports 302 in the slurry receiving tank 303.
The internal pressure of the foam recovery pipe 310 that efficiently recovers the foam in the slurry receiving tank 303 is a value measured by the micro pressure gauge 304, and is −10 to 0 kPa, more preferably −5 to −1 kPa. When the measured value by the micro pressure gauge 304 exceeds 0 kPa, the foam generated in the slurry receiving tank 303 cannot be recovered, and the generated foam flows backward from the slurry receiving inlet 302 and enters the lower part and the upper part of the screen of the sieving device. Stable sieving becomes difficult. In addition, when the measured value with the micro pressure gauge 304 is less than −10 kPa, the force of pressing from the upper part of the screen toward the lower part in the sieving device increases, and the coarse powder in the toner slurry is attracted to the screen, causing clogging, and stable. Sifting becomes difficult.

  The following is a slurry sieving method for sieving the particles in the slurry supplied from the upper part of the screen using a vibrating sieve, wherein the lower part of the screen is opened to the atmosphere, or an example of a sieving method performed with a slight negative pressure. (Example 1 and Example 2) are shown.

(Example 1)
--Preparation of resin fine particle dispersion 1--
Styrene: 288 parts n-butyl acrylate: 112 parts Acrylic acid: 8 parts Dodecane thiol: 8 parts Hexanediol diacrylate: 2 parts The above components were mixed and dissolved to prepare a resin solution in advance.
On the other hand, 6 parts of a nonionic surfactant (Sanyo Kasei Co., Ltd., Nonipol 400) and 9 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R: sodium dodecylbenzenesulfonate) were added to ion-exchanged water 612. The resin solution was dispersed and emulsified, and 100 parts of ion-exchanged water in which 4 parts of ammonium persulfate was dissolved was added while slowly mixing for 10 minutes to perform nitrogen substitution. Thereafter, the content is heated to 70 ° C. while stirring, and emulsion polymerization is continued for 6 hours. The anion having a dispersed resin particle volume average particle size of 155 nm, a glass transition point of 57 ° C., and Mw of 31,500. Resin fine particle dispersion 1 was obtained.

-Preparation of magnetic powder 1-
To 150 parts of water and 40 parts of 15.5N aqueous sodium hydroxide prepared in a reactor equipped with a stirrer in advance, 200 parts of ferrous sulfate having a concentration of 1.30 parts / liter was added, pH value was 13, temperature After producing a ferrous salt aqueous solution containing 85 ° C. ferrous hydroxide, 180 parts of air was aerated for 90 minutes at a temperature of 90 ° C. to produce magnetite particles. The produced particles were washed with water, filtered, dried and pulverized by a conventional method to obtain particle powder. After 500 parts of the obtained magnetite particle powder was dispersed in 85 ° C. water, sodium hydroxide was added dropwise with stirring to adjust the pH value to 11. Next, an aqueous solution containing 19.0 parts of 0.60 weight aluminum sulfate in terms of Al was added to the particles, the pH value was adjusted to 7, and the mixture was stirred for 45 minutes. This was washed with water, filtered and dried to obtain magnetic powder particles 1 whose surface was treated with aluminum. The Al content on the surface of the obtained particles was 0.55% by weight.

-Preparation of magnetic powder dispersion 1-
-Magnetic powder particles 1 ... 450 parts-Cationic surfactant (manufactured by Kao Corporation, Sanisol B50)-50 parts-Ion-exchanged water-500 parts or more are mixed and homogenizer (manufactured by IKA, Ultra Turrax T50) Then, using a counter collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.), a dispersion treatment was performed at a pressure of 245 MPa for 20 minutes to obtain a magnetic powder dispersion 1. The volume center particle size of the magnetic powder in the obtained magnetic powder dispersion 1 was 155 nm.

--Preparation of release agent dispersion 1--
Paraffin wax (Nippon Seiwa Co., Ltd., HNPO190, melting point 85 ° C.) 50 parts Cationic surfactant (Kao Corporation, Sanizol B50) 7.5 parts Ion-exchanged water 192.5 parts The mixture was heated to 95 ° C. and dispersed using a homogenizer to obtain a wax dispersion. The average particle size of the dispersed wax was 250 nm.

--- Production of aggregated particles--
・ Resin fine particle dispersion 1 ... 200 parts ・ Magnetic powder dispersion 1 ... 30 parts ・ Releasing agent dispersion 1 ... 40 parts ・ Cationic surfactant (Sanisol B50, manufactured by Kao Corporation) ... 1.5 parts ・ Ion exchange Water: 600 parts The above components were mixed and dispersed using a homogenizer, heated to 48 ° C with stirring, and then maintained at 50 ° C for 90 minutes. When the dispersion liquid obtained at that time was observed with an optical microscope, aggregated particles having a volume average particle diameter (D _50v ) of 6.2 μm were confirmed.
To the above dispersion, 60 parts of the resin fine particle dispersion 1 was gradually added and held at the same temperature (50 ° C.) for 1 hour. When the obtained dispersion was observed with an optical microscope, aggregated particles having a volume average particle diameter (D _50v ) of about 6.5 μm were confirmed.

Next, 5 parts of anionic surfactant sodium dodecylbenzenesulfonate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) is added to the obtained dispersion, heated to 97 ° C., and held for 7 hours to aggregate particles. Fused. Thereafter, the mixture was cooled to 30 ° C. to obtain a toner slurry A having a solid content concentration of 15 wt%. When the volume average particle size (D _50v ) of the fused particles was measured with a Coulter counter, it was 6.7 μm. The shape factor SF1 determined by the image analysis apparatus was 127. The volume average particle diameter Dv and the content of coarse particles were measured with a 50 μm diameter aperture using a Coulter counter [TA-II] type (manufactured by Coulter). At this time, the measurement was performed after the toner was dispersed in isotone and then dispersed for 30 seconds or more by ultrasonic waves to break up the aggregated particles. As a result, the 84% volume reference particle diameter is 7.5 μm, the amount of coarse powder of 20 μm or more is 0.9 vol% of the total amount of resin fine particles, and the amount of coarse powder of 15 μm or more is 1. It was 2 vol%.
The toner slurry A was sieved with a circular vibrating sieve shown in FIG. 5 and collected in a slurry receiving tank. A net frame having an effective diameter of 720 was used. The fine pressure gauge attached to the foam recovery pipe adjusted the supply air pressure to the ejector so as to be −3 to −1 kPa. As the screen, a nylon mesh having a 20 μm mesh was used, and a nylon mesh having a 600 μm mesh was placed on the bottom. The vibration frequency is adjusted to 35 s ⁻¹ , the amplitude in the vertical direction with respect to the mesh of the sieve frame (p) is 5 mm, and the amplitude in the horizontal direction with respect to the mesh of the sieve frame is 3 mm. At a flow rate of The foam generated in the slurry receiving tank was guided to the foam recovery tank through the foam recovery pipe, and could be extinguished by the dropped antifoaming agent. In addition, the gas generated from the foam recovery tank was sucked with an exhaust gas fan, deodorized with a scrubber, and then exhausted outdoors, so it was possible to keep the working environment clean. In this way, when the toner slurry was supplied for 534 minutes, the number of times the slurry overflowed from the net was zero. As a result of measuring the sieved slurry with a Coulter counter, the amount of particles exceeding 20 μm was 0.1 vol%.
Here, the overflow is defined when the accumulated amount of the slurry flowing out from the coarse powder outlet on the net is 5 kg. If the bubbles in the sieving device are left unattended, the operation becomes impossible in the end, and when overflow occurs, the supply of the toner slurry is stopped and the bubbles are removed.

(Example 2)
The same procedure as in Example 1 was performed except that the air pressure supplied to the ejector was adjusted to −8 to −6 kPa with a micro pressure gauge attached to the foam recovery pipe, and the toner slurry A was fed at a flow rate of 1000 kg / h. Continuous supply. When the toner slurry was supplied for 519 minutes, the number of times the slurry overflowed from the net was zero. As a result of measuring the sieved slurry with a Coulter counter, the amount of particles exceeding 20 μm was 0.1 vol%.

Examples 1-5
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but these do not limit the present invention. Here, “parts” means “parts by weight” unless otherwise specified.
Example 1
The resin particle dispersion 1, the magnetic powder dispersion 1, and the release agent dispersion 1 were aggregated at the following ratio to obtain aggregated particles.

--Preparation of aggregated particles--
-Resin particle dispersion 1: 87.5 parts (equivalent to 35% by weight)
-Magnetic powder dispersion 1 ... 89 parts (equivalent to 40% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
-Cationic surfactant (manufactured by Kao Corporation, Sanizol B50) ... 1.5 parts or more in a round stainless steel flask after mixing and dispersing using a homogenizer (IKA, Ultra Turrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of 6.2 μm were formed.

<Second step>
--Preparation of adhered particles--
37.5 parts (corresponding to 15% by weight) of dispersion 1 as a resin-containing fine particle dispersion was gently added to the obtained aggregated particle dispersion. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having a volume average particle diameter of 6.6 μm were formed.

<Third step>
Then, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal while maintaining the temperature at 105 ° C. And heated for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.

  When the particle size of the obtained toner for developing an electrostatic charge image was measured using a Coulter counter, the volume average center particle size was 6.5 μm, the volume GSD was 1.21, and the number GSD was 1.22. there were. The shape factor SF1 was 120. When the surface state was observed with an electron microscope, exposure of the magnetic powder and wax-like material to the surface of the electrostatic charge image developing toner was not observed, and free magnetic powder was not observed.

(Example 2)
-Preparation of magnetic powder 2-
Magnetite particle powder was obtained by the method shown in the preparation of the magnetic powder (1). After 500 parts of the obtained magnetite particle powder was dispersed in 85 ° C. water, sodium hydroxide was added dropwise with stirring to adjust the pH value to 11. Next, an aqueous solution containing 31.7 parts of 1.00 weight aluminum sulfate in terms of Al was added to the particles, the pH value was adjusted to 7, and the mixture was stirred for 60 minutes. This was washed with water, filtered and dried to obtain magnetic powder particles (2) whose surface was treated with aluminum. The Al content of the obtained particle surface was 0.92% by weight.

-Preparation of magnetic powder dispersion 2-
-Magnetic powder particles 2 ... 450 parts-Cationic surfactant (manufactured by Kao Corporation, Sanisol B50)-50 parts-Ion-exchanged water-500 parts or more are mixed, and a homogenizer (manufactured by IKA, Ultra Turrax T50) Then, using a counter collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.), a dispersion treatment was performed at a pressure of 245 Mpa for 20 minutes to obtain a magnetic powder dispersion (2). The volume average particle diameter of the magnetic powder in the obtained magnetic powder dispersion (2) was 148 nm.

--Preparation of aggregated particles--
-Resin dispersion 1 ... 87.5 parts (equivalent to 35% by weight)
-Magnetic powder dispersion 2 ... 89 parts (equivalent to 40% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
-Cationic surfactant (manufactured by Kao Corporation, Sanizol B50) ... 1.5 parts or more in a round stainless steel flask after mixing and dispersing using a homogenizer (IKA, Ultra Turrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, it was confirmed by observation with an optical microscope that aggregated particles having a volume average particle diameter of 6.0 μm were formed.

<Second step>
--Preparation of adhered particles--
37.5 parts (corresponding to 15% by weight) of dispersion 1 as a resin-containing fine particle dispersion was gently added to the obtained aggregated particle dispersion. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having a volume average particle diameter of 6.4 μm were formed.

<Third step>
Then, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal while maintaining the temperature at 105 ° C. And heated for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.
When the particle size of the obtained toner for developing an electrostatic charge image was measured using a Coulter counter, the volume average center particle size was 6.4 μm, the volume GSD was 1.21, and the number GSD was 1.23. there were. The shape factor SF1 was 122. When the surface state was observed with an electron microscope, exposure of the magnetic powder and wax-like material to the surface of the electrostatic charge image developing toner was not observed, and free magnetic powder was not observed.

(Example 3)
-Preparation of magnetic powder 3-
Magnetite particle powder was obtained by the method shown in the preparation of magnetic powder 1. After 500 parts of the obtained magnetite particle powder was dispersed in 85 ° C. water, sodium hydroxide was added dropwise with stirring to adjust the pH value to 11. Next, an aqueous solution containing 14.9 parts of 0.60 weight magnesium sulfate in terms of Mg was added to the particles, the pH value was adjusted to 7, and the mixture was stirred for 45 minutes. This was washed with water, filtered and dried to obtain magnetic powder particles 3 whose surface was treated with magnesium. The Mg content on the surface of the obtained particles was 0.56% by weight.

-Preparation of magnetic powder dispersion 3-
-Magnetic powder particles 3 ... 450 parts-Cationic surfactant (manufactured by Kao Corporation: Sanizol B50) ... 50 parts-Ion-exchanged water--500 parts Then, using a counter collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.), a dispersion treatment was performed at a pressure of 245 MPa for 20 minutes to obtain a magnetic powder dispersion (3). The volume average particle diameter of the magnetic powder in the obtained magnetic powder dispersion (3) was 152 nm.

--Preparation of aggregated particles--
-Resin dispersion 1 ... 87.5 parts (equivalent to 35% by weight)
-Magnetic powder dispersion 3 ... 89 parts (equivalent to 40% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
Cationic surfactant (manufactured by Kao Corporation: Sanizol B50): 1.5 parts After mixing and dispersing the above in a round stainless steel flask using a homogenizer (IKA, Ultra Tarrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, it was confirmed by observation with an optical microscope that aggregated particles having a volume average particle diameter of 5.9 μm were formed.

<Second step>
--Preparation of adhered particles--
37.5 parts (corresponding to 15% by weight) of the dispersion liquid (1) as the resin-containing fine particle dispersion liquid was gently added to the obtained aggregated particle dispersion liquid. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having a volume average particle diameter of 6.5 μm were formed.

<Third step>
Then, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal while maintaining the temperature at 105 ° C. And heated for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.
When the particle size of the obtained toner for developing an electrostatic charge image was measured using a Coulter counter, the volume average particle size was 6.4 μm, the volume GSD was 1.22, and the number GSD was 1.22. It was. The shape factor SF1 was 123. When the surface state was observed with an electron microscope, exposure of the magnetic powder and wax-like material to the surface of the electrostatic charge image developing toner was not observed, and free magnetic powder was not observed.

Example 4
--Preparation of aggregated particles--
-Resin dispersion 1 70 parts (equivalent to 28% by weight)
Magnetic powder dispersion 1 ... 111.1 parts (equivalent to 50% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
-Cationic surfactant (manufactured by Kao Corporation, Sanizol B50) ... 1.5 parts or more in a round stainless steel flask after mixing and dispersing using a homogenizer (IKA, Ultra Turrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, it was confirmed by observation with an optical microscope that aggregated particles having a volume average particle size of 6.2 μm were formed.

<Second step>
--Preparation of adhered particles--
To the obtained aggregated particle dispersion, 30 parts (corresponding to 12% by weight) of Dispersion 1 as a resin-containing fine particle dispersion was gently added. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having an average particle diameter of 6.7 μm were formed.

<Third step>
Then, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal while maintaining the temperature at 105 ° C. And heated for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.
When the particle size of the obtained toner for developing an electrostatic charge image was measured using a Coulter counter, the volume average particle size was 6.6 μm, the volume GSD was 1.23, and the number GSD was 1.25. It was. The shape factor SF1 was 126. When the surface state was observed with an electron microscope, exposure of some magnetic powder was confirmed on the surface of the electrostatic charge developing toner. However, no free wax was observed.

(Example 5)
--Preparation of aggregated particles--
-Resin dispersion 1 ... 112.5 parts (equivalent to 45% by weight)
-Magnetic powder dispersion 1 ... 55.6 parts (corresponding to 25% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
-Cationic surfactant (manufactured by Kao Corporation: Sanizol B50) ... 1.5 parts or more after mixing and dispersing in a round stainless steel flask using a homogenizer (manufactured by IKA, Ultra Turrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, it was confirmed by observation with an optical microscope that aggregated particles having a volume average particle size of 6.2 μm were formed.

<Second step>
--Preparation of adhered particles--
To the obtained aggregated particle dispersion, 50 parts (corresponding to 20% by weight) of Dispersion 1 as a resin-containing fine particle dispersion was gradually added. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having a volume average particle diameter of 6.7 μm were formed.

<Third step>
Then, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal while maintaining the temperature at 105 ° C. And heated for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.
When the particle size of the obtained electrostatic charge image developing toner was measured using a Coulter counter, the volume average particle size was 6.6 μm, the volume GSD was 1.20, and the number GSD was 1.21. It was. The shape factor SF1 was 122. When the surface state was observed with an electron microscope, exposure of the magnetic powder and wax-like material to the surface of the electrostatic charge image developing toner was not observed, and free magnetic powder was not observed.

(Comparative Example 1)
-Preparation of magnetic powder 4-
Magnetite particle powder was obtained by the method shown in the preparation of magnetic powder 1. After 500 parts of the obtained magnetite particle powder was dispersed in 85 ° C. water, sodium hydroxide was added dropwise with stirring to adjust the pH value to 11. Next, an aqueous solution containing 11.9 parts of titanium chloride of 0.60 weight in terms of Ti was added to the particles, the pH value was adjusted to 7, and the mixture was stirred for 45 minutes. This was washed with water, filtered and dried to obtain magnetic powder particles 4 whose surface was treated with titanium. The Ti content on the obtained particle surface was 0.54% by weight.

-Preparation of magnetic powder dispersion 4-
-Magnetic powder particles 4 ... 450 parts-Cationic surfactant (manufactured by Kao Corporation, Sanisol B50)-50 parts-Ion-exchanged water-500 parts or more are mixed, and a homogenizer (manufactured by IKA, Ultra Turrax T50) Then, using a counter collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.), a dispersion treatment was performed at a pressure of 245 MPa for 20 minutes to obtain a magnetic powder dispersion (4). The volume average particle diameter of the magnetic powder in the obtained magnetic powder dispersion (4) was 160 nm.

--Preparation of aggregated particles--
-Resin dispersion 1 ... 87.5 parts (equivalent to 35% by weight)
-Magnetic powder dispersion 4 ... 89 parts (equivalent to 40% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
-Cationic surfactant (manufactured by Kao Corporation, Sanizol B50) ... 1.5 parts or more in a round stainless steel flask after mixing and dispersing using a homogenizer (IKA, Ultra Turrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, observation with an optical microscope confirmed that aggregated particles having a volume average particle size of 6.1 μm were formed.

<Second step>
--Preparation of adhered particles--
37.5 g (corresponding to 15% by weight) of dispersion 1 as a resin-containing fine particle dispersion was gradually added to the obtained aggregated particle dispersion. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having a volume average particle diameter of 6.6 μm were formed.

A
<Third step>
Then, after adding 3 g of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal up to 105 ° C. Heated and held for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.
When the particle size of the obtained toner for developing an electrostatic charge image was measured using a Coulter counter, the volume average particle size was 6.5 μm, the volume GSD was 1.23, and the number GSD was 1.25. It was. The shape factor SF1 was 125. When the surface state was observed with an electron microscope, exposure of some magnetic powder was confirmed on the surface of the electrostatic charge developing toner. Moreover, some free magnetic powder was confirmed.

(Comparative Example 2)
-Preparation of magnetic powder 5-
Magnetite particle powder was obtained by the method shown in the preparation of magnetic powder 1. After 500 parts of the obtained magnetite particle powder was dispersed in 85 ° C. water, sodium hydroxide was added dropwise with stirring to adjust the pH value to 10. Next, an aqueous solution containing 11.7 parts of 0.60 weight sodium silicate in terms of Si was added to the particles, the pH value was adjusted to 7, and the mixture was stirred for 45 minutes. This was washed with water, filtered and dried to obtain magnetic powder particles (4) whose surface was treated with silicon. The Si content on the obtained particle surface was 0.55% by weight.

-Preparation of magnetic powder dispersion (5)-
・ The above magnetic powder particles (5): 450 parts ・ Cationic surfactant (manufactured by Kao Corporation, SANISOL B50): 50 parts ・ Ion-exchanged water: 500 parts or more are mixed, and a homogenizer (manufactured by IKA, Ultrata) After dispersion using Lux T50), dispersion treatment was performed for 20 minutes at a pressure of 245 MPa using an opposing collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.) to obtain a magnetic powder dispersion (5). The volume average particle diameter of the magnetic powder in the obtained magnetic powder dispersion (4) was 153 nm.

--Preparation of aggregated particles--
-Resin dispersion 1 ... 87.5 parts (equivalent to 35% by weight)
-Magnetic powder dispersion 5 ... 89 parts (equivalent to 40% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
-Cationic surfactant (manufactured by Kao Corporation, Sanizol B50) ... 1.5 parts or more in a round stainless steel flask after mixing and dispersing using a homogenizer (IKA, Ultra Turrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, it was confirmed by observation with an optical microscope that aggregated particles having a volume average particle diameter of 5.9 μm were formed.

<Second step>
--Preparation of adhered particles--
37.5 parts (corresponding to 15% by weight) of the dispersion liquid (1) as the resin-containing fine particle dispersion liquid was gently added to the obtained aggregated particle dispersion liquid. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having a volume average particle diameter of 6.4 μm were formed.

<Third step>
Then, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal while maintaining the temperature at 105 ° C. And heated for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.
When the particle size of the obtained toner for developing an electrostatic image was measured using a Coulter counter, the volume average particle size was 6.3 μm, the volume GSD was 1.24, and the number GSD was 1.26. It was. The shape factor SF1 was 130. When the surface state was observed with an electron microscope, it was confirmed that the magnetic powder was exposed on the surface of the electrostatic charge developing toner. Moreover, some free magnetic powder was also confirmed.

(Comparative Example 3)
--Preparation of aggregated particles--
-Resin dispersion 1 70 parts (equivalent to 28% by weight)
Magnetic powder dispersion 5 ... 111.1 parts (equivalent to 50% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
-Cationic surfactant (manufactured by Kao Corporation: Sanizol B50) ... 1.5 parts or more after mixing and dispersing in a round stainless steel flask using a homogenizer (manufactured by IKA, Ultra Turrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, it was confirmed by observation with an optical microscope that aggregated particles having a volume average particle diameter of 6.4 μm were formed.

<Second step>
--Preparation of adhered particles--
To the obtained aggregated particle dispersion, 30 parts (corresponding to 12% by weight) of Dispersion 1 as a resin-containing fine particle dispersion was gently added. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having a volume average particle diameter of 6.8 μm were formed.

<Third step>
Then, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal while maintaining the temperature at 105 ° C. When the particles were heated to the point where the particles began to aggregate, the heating was stopped and the experiment was stopped.

(Comparative Example 4)
--Preparation of aggregated particles--
-Resin dispersion 1 ... 112.5 parts (equivalent to 45% by weight)
-Magnetic powder dispersion 5: 55.6 parts (equivalent to 25% by weight)
Release agent dispersion 1 ... 50 parts (equivalent to 10% by weight)
-Cationic surfactant (manufactured by Kao Corporation, Sanizol B50) ... 1.5 parts or more in a round stainless steel flask after mixing and dispersing using a homogenizer (IKA, Ultra Turrax T50) The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, it was confirmed by observation with an optical microscope that aggregated particles having a volume average particle diameter of 5.9 μm were formed.

<Second step>
--Preparation of adhered particles--
37.5 parts (corresponding to 15% by weight) of dispersion 1 as a resin-containing fine particle dispersion was gently added to the obtained aggregated particle dispersion. And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having a volume average particle diameter of 6.5 μm were formed.

<Third step>
Then, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal while maintaining the temperature at 105 ° C. And heated for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.
When the particle size of the obtained toner for developing an electrostatic charge image was measured using a Coulter counter, the volume average center particle size was 6.4 μm, the volume GSD was 1.23, and the number GSD was 1.25. there were. The shape factor SF1 was 128. When the surface state was observed with an electron microscope, a slight amount of magnetic powder and a wax-like substance were exposed on the surface of the electrostatic charge image developing toner, but no free magnetic powder was observed.

(Comparative Example 5)
The resin, magnetic powder, and release agent prepared in Example 1 were mixed in the following proportions in a dry product state without being in a dispersion state.
・ Resin: 100 parts (50% by weight)
・ Magnetic powder: 80 parts (40% by weight)
Release agent: 20 parts (10% by weight)
This mixture was melted and kneaded at 130 ° C. with an extruder, coarsely pulverized with a cutter mill, and further pulverized with a fine pulverizer using a jet stream. The obtained pulverized product was classified using an air classifier to obtain an electrostatic image developing toner. When the particle size of the obtained toner for developing an electrostatic charge image was measured using a Coulter counter, the average center particle size was 6.4 μm, the volume GSD was 1.30, and the number GSD was 1.38. . The shape factor SF1 was 153. When the surface state is observed with an electron microscope, the exposure of the magnetic powder and wax-like material to the surface of the toner for developing an electrostatic charge image is clearly larger than that of the toner produced by the emulsion polymerization aggregation method. Was also seen.

<Preparation of developer>
To 50 parts of the toner particles of Examples 1 to 5 and Comparative Examples 1, 2, 4, and 5, 1.5 parts of hydrophobic silica (TS720, manufactured by Cabot Corporation) is added and mixed using a sample mill. Added. Of these, the toner concentration of the externally added toner of Example 5 and Comparative Example 4 is 1% by weight of polymethylmethacrylate (molecular weight 50000, manufactured by Soken Chemical Co., Ltd.) and the ferrite carrier has a volume average particle size of 50 μm. A developer was prepared by weighing to 10% and stirring and mixing with a ball mill for 5 minutes.

<Evaluation>
Using the externally added toners of Examples 1 to 4 and Comparative Examples 1, 2, and 5, using a modified machine of “DocuPrint 211” manufactured by Fuji Xerox Co., Ltd., images were recorded under a summer environment (30 ° C., 85% RH). The film was formed and visually evaluated for image quality. The images obtained using the externally added toners of Examples 1 to 3 were clear, excellent in developability, and good images with no background stains. The image obtained using the external additive toner of Example 4 was clear, but some scattering was observed in the background portion. The image obtained using the externally added toner of Comparative Example 1 was clear, but some scattering was observed in the background portion. The image obtained using the externally added toner of Comparative Example 2 was slightly inferior in graininess, and a slight scattering on the background was observed. The image obtained using the externally added toner of Comparative Example 5 was inferior in graininess, and was scattered more in the background area than other toners.

Using the developer of Example 5 and toner added externally and using a modified model of “Vivace 555” manufactured by Fuji Xerox Co., Ltd., an image having an image density of 5% under a summer environment (30 ° C., 85% RH) After copying 10,000 sheets, an image was formed and the image quality was visually evaluated. The obtained image was clear, excellent in developability, and a good image with no background stains. Further, using the developer of Comparative Example 4 and the externally added toner, the same evaluation was made. The obtained image was inferior in granularity as compared with Example 5, and some scattering was confirmed in the background portion.
Further, when 2.5 g of toner particles of Examples 1 to 5 and Comparative Examples 1, 2, 4 and 5 and 50 g of the ferrite carrier were mixed and shaken for 5 minutes to measure the charge amount, The values were 33, 34, 28, 25, 35, 23, 18, 22, and 30 μC / g. The evaluation results are shown below as “Table 1”.

Examples 6-8
Examples 6 to 8 below are examples (and comparative examples) relating to a method for mixing and drying an electrostatic charge image developing toner that is dried (secondary drying) in combination with the attachment and fixation of an external additive to the toner. ). However, the toner contains a colorant but does not contain magnetic powder.
(Example 6)
[Manufacture of toner base particles]
-Preparation of resin fine particle dispersion-
・ Styrene (made by Wako Pure Chemical Industries) ... 320 parts,
N butyl acrylate (Wako Pure Chemical Industries) ... 80 parts,
Β carboxyethyl acrylate (manufactured by Rhodia Nikka)… 9 parts,
1,10 decanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) ... 1.5 partsDodecanethiol (manufactured by Wako Pure Chemical Industries) ... 2.7 parts
The above is mixed and dissolved, dissolved in 550 parts of ion-exchanged water containing 4 parts of the anionic surfactant Dowfax (manufactured by Dow Chemical Co., Ltd.), further dispersed and emulsified in a stirring tank, and slowly stirred for 10 minutes. While mixing, 50 parts of ion-exchanged water in which 6 parts of ammonium persulfate was dissolved was added. Next, after sufficiently replacing the nitrogen in the system, the stirring tank jacket was heated while stirring in the stirring tank until the temperature in the tank reached 70 ° C., and emulsion polymerization was continued for 5 hours. Thus, an anionic resin particle dispersion having a volume average particle size of 220 nm, a solid content of 42.9%, a glass transition point of 51.0 ° C., and an Mw of 31000 was prepared.

-Preparation of colorant particle dispersion-
-Phthalocyanine pigment (manufactured by Dainichi Seika Co., Ltd., PVFASTBLUE) ... 90 parts,
Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) ... 10 parts,
・ Ion exchange water: 240 parts,
The above was mixed in a stirring vessel and dispersed using an optimizer HJP-25008 (manufactured by Sugino Machine Co., Ltd.) set at a dispersion pressure of 196 MPa to prepare a colorant particle dispersion. The number average particle diameter of the colorant in the colorant dispersion was 125 nm.

-Preparation of release agent dispersion-
Paraffin wax (Nippon Seiwa Co., Ltd., HNPO190: melting point 85 ° C.) 50 parts,
-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) ... 7.5 parts,
-Ion-exchanged water: 200 parts The above components were heated to 95 ° C, dispersed using a homogenizer, and then dispersed with a dyno mill to obtain a wax dispersion. The average particle size of the dispersed wax was 245 nm. Microtrac (manufactured by Nikkiso Co., Ltd., Microtrac UPA9340) was used for particle size measurement of these resin particle dispersion, colorant dispersion, and release agent dispersion.

-Preparation of toner particles-
(Aggregation process)
・ Ion exchange water: 400 parts,
-Resin particle dispersion: 240 parts,
Colorant dispersion: 44 parts
-Release agent dispersion liquid: 56 parts,
Inorganic fine particle dispersion (Nissan Chemical Co., Snowtex OL) ... 12 parts
Inorganic fine particle dispersion (Nissan Chemical Co., Snowtex OS) ... 10 parts,
After the above mixed components are put into a stirring tank and thoroughly mixed and dispersed with a homogenizer,
・ Flocculant (Asada Chemical Co., Ltd., polyaluminum chloride): 0.5 part
・ Ion exchange water: 100 parts,
The mixed solution was added over 10 minutes while stirring the stirring tank, and after the addition, the mixture was gently heated to 40 ° C. and held for 30 minutes, and then heated to 50 ° C. After holding at 50 ° C. for 40 minutes, when the particle size was measured with a Coulter counter (Multisizer 2 manufactured by Coulter, Inc.), it was confirmed that aggregated particles having a volume average particle diameter of 4.6 μm were formed. Further, the temperature of the heating jacket was raised and held at 52 ° C. for 40 minutes. When the particle size (volume average particle diameter, the same applies hereinafter) was measured, it was confirmed that 3.7 μm aggregated particles were generated.

(Adhesion process)
To the dispersion containing the aggregated particles prepared above, 65 parts of the resin particle dispersion was further slowly added, and the temperature of the heating jacket was raised and held at 54 ° C. for 1 hour. The obtained adhered particles were measured to have a particle size of 5.5 μm.

(Fusion process)
Next, a 1 mol / liter aqueous sodium hydroxide solution was added so that the pH was 6.0, and then the mixture was gently heated to 85 ° C. and kept for 60 minutes while continuing stirring. Thereafter, the mixture was heated to 96 ° C., a 1 mol / liter nitric acid aqueous solution was added until pH 5.0, and the mixture was held for 5 hours.
Thereafter, the obtained toner slurry was cooled to 42 ° C., and this slurry was further subjected to sieving treatment with a mesh having a mesh size of 15 μm, followed by filtration with a filter press (manufactured by Tokyo Engineering Co., Ltd.).
200 parts of ion-exchanged water (conductivity of 2 μS or less) is passed through the toner in the filter press apparatus with respect to 100 parts of the resulting colorant resin fine particles, followed by 1 mol / liter nitric acid aqueous solution in 300 parts of ion-exchanged water. Was passed through acid-washed water added until pH 3.0, and further 500 parts of ion-exchanged water were passed through, and after pressing and dewatering, a toner cake having a water content of 37% was obtained. The moisture content is based on the moisture content, and was measured at 105 ° C. for 20 minutes using Sartorius MA30.
After the toner cake was crushed, it was dried with an airflow dryer (FJD-2 flash jet dryer, manufactured by Seishin Enterprise Co., Ltd.) at a dry toner standard of 8 kg / h and an outlet temperature of 44 ° C. 65% toner was obtained.

A Henschel mixer FM75J / I manufactured by Mitsui Mining Co., Ltd. was used as a mixing / drying device for external additives, and Zo blades and Bo blades were used as mixing blades.
As the powder used, 9 kg of the above toner and 90 g of silica X24-9163A manufactured by Shin-Etsu Chemical Co., Ltd., a large particle size silica as an additive were used. That is, the concentration of the charged silica was 1 wt%. The mixing time was 30 min when the upper blade tip peripheral speed was 40 m / s. After the start of mixing, 5 m elapsed, 9 m ³ / h of atmospheric air was injected from the nozzle provided on the upper lid of the mixing / drying apparatus in terms of the dew point of −0.3 ° C. A deaeration filter EF (model number 125AF) was attached as a filter to the upper lid of the mixing / drying apparatus, connected to an exhaust fan, and pulsed air for backwashing was also supplied. The pulse interval was 1 time / 1 minute. For cooling in the mixing / drying apparatus, a refrigerant was passed from immediately after the start of mixing to the end of mixing. Mixing was repeated 6 batches with the same dry toner and the same mixing conditions.

--Evaluation of processed toner--
In addition to moisture measurement, the silica concentration in the toner was measured with a wavelength dispersive X-ray fluorescence analyzer LABCENTER XRF-1500 manufactured by Shimadzu Corporation. Further, 20 g of toner was sampled and sieved with a 45 μm mesh sieve, and the number of coarse particles remaining on the sieve was counted. Further, the recovery rate of the toner with the external additive after the mixing process was also determined. The results are shown in Table 2.

(Example 7)
The same dry toner as in Example 6 was used. Six batches were mixed in the same manner as in Example 6 except that 12000 parts of toner, 120 parts of large particle size silica, and instrument air with a dew point of −0.3 ° C. were injected at 14.4 m ³ / h in air. did. Cooling in the mixing / drying apparatus was performed even when unmixed.

(Example 8)
The same dry toner as in Example 6 was used. Six batches were mixed in the same manner as in Example 6 except that 9000 parts of toner, 90 parts of large particle size silica, and instrument air with a dew point of −0.3 ° C. were injected at 10.8 m ³ / h in air. did. The mixing / drying apparatus was cooled immediately after the start of mixing until the end of mixing.

(Comparative Example 6)
The same dry toner as in Example 6 was used. Six batches were repeatedly mixed in the same manner as in Example 6 except that 9000 toner, 90 parts of large particle size silica, and instrument air having a dew point of -0.3 ° C were injected at 1.8 m ³ / h in terms of air. . The mixing / drying apparatus was cooled immediately after the start of mixing until the end of mixing.

(Comparative Example 7)
The same dry toner as in Example 6 was used. Six batches were repeatedly mixed in the same manner as in Example 6 except that 12000 toner, 120 parts of large particle size silica, and instrument air with a dew point of -0.3 ° C were injected at 1.8 m ³ / h in terms of air. . Cooling in the mixing / drying apparatus was performed even when unmixed.

FIG. 3 is a schematic configuration diagram of an example of a mixing / drying apparatus used for adhesion, mixing, and drying (secondary drying) of an external additive to a toner in the present invention. It is a schematic block diagram which shows the conventional vibration sieve. It is a figure (plan view) explaining the principal part of a vibration motor. It is a figure (front view) explaining the phase angle of a vibration motor. It is a schematic block diagram which shows the whole slurry sieving apparatus used by this invention.

Explanation of symbols

C, D
10: Mixing / drying device,
11: Rotating blade,
12: Rotating blade,
13: motor,
14: Jacket,
15: Raw material supply port,
16: Mixing / drying room
17: Gas pipe for rotating shaft seal,
18: Flow meter,
19: Gas inlet for drying,
20: flow meter,
21: Filter,
22: Fan,
23: Instrument air for pulse air,
100: base frame,
102: Coil spring,
104: sieve frame,
105: upper frame,
106: bottom,
108: sieve mesh,
110: Support frame,
116: Sieving product collection port,
118: Supply port,
120: coarse powder outlet,
122: upper lid,
130: Vibration motor,
132: arcuate hole,
134: board
136, 140: fixing bolt,
204: output shaft,
θw: weight phase angle (°),
301: Slurry discharge hose,
302: Slurry receiving port,
303: slurry receiving tank,
304: micro pressure gauge,
305: Ejector,
306: Bubble recovery tank,
307: Scrubber,
308: exhaust gas fan,
309: Slaver pump,
310: Bubble recovery piping

Claims (5)

  An electrostatic image developing toner containing a binder resin, magnetic powder, and a release agent, wherein the toner has a shape factor of 110 or more and 140 or less, and the surface of the magnetic powder is subjected to a basic treatment with a metal compound. A toner for developing an electrostatic charge image. In the first dispersion obtained by dispersing at least resin particles, the resin particles, at least one kind of magnetic powder whose surface is basic-treated with a metal compound, at least one kind of release agent, and / or other particles An agglomeration step of mixing a second dispersion obtained by dispersing the resin particles to form a dispersion of aggregated particles comprising the resin particles, the magnetic powder, and the release agent;
An adhesion step of adding and mixing at least a dispersion obtained by dispersing resin particles in the aggregated particle dispersion to form a dispersion of adhered particles in which the resin particles are adhered to the aggregated particles;
A fusion step in which the adhered particle dispersion is heated to a temperature equal to or higher than the glass transition point of the resin contained in the adhered particles to fuse the adhered particles to form a dispersion of fused particles; A method for producing a toner for developing an electrostatic charge image, comprising a separation drying step of separating and drying.   An electrostatic charge image developing developer comprising a carrier and a toner, wherein the toner is the electrostatic charge developing toner according to claim 1.   Forming a latent electrostatic image on the latent electrostatic image bearing member, developing the latent electrostatic image with a developer on the developer bearing member to form a toner image, and transferring the toner image onto the transfer member. 2. The static developer according to claim 1, wherein the developer comprises: a step of fixing a toner image on the transfer member; and a cleaning step of removing toner remaining on the electrostatic latent image carrier. An image forming method using the charge developing toner or the electrostatic charge developing developer according to claim 3. Mixing of toner for developing an electrostatic charge image to which an external additive is adhered and fixed to the toner particles according to claim 1 and dried (secondary drying) using a mixing / drying device provided with a stirring means in the mixing / drying chamber. In the drying method, the total amount (flow velocity) F [m ³ / h] of the gas for sealing the rotating shaft of the stirring means and / or the gas supplied from the separately provided gas supply port was fed into the mixing / drying apparatus. A method for mixing and drying an electrostatic charge image developing toner, wherein the toner amount [kg] is adjusted so that 0.3 ≦ F / W ≦ 1.5.

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