JP2006091378A - Electrophotographic toner, method for manufacturing electrophotographic toner, and electrostatic charge image developer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic toner having excellent low temperature fixing property, high durability and preferable cleaning property and transfer property, to provide a method for manufacturing the toner, and to provide an electrostatic charge image developer using an electrophotographic toner. <P>SOLUTION: The electrophotographic toner contains toner particles comprising core particles containing at least a crystalline binder resin, the particles coated with a coating agent containing an amorphous polymer, and an external additive. The toner particle contains a plurality of core particles. The invention also provides a method for manufacturing the toner, and an electrostatic charge image developer using the electrophotographic toner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic toner suitably used for image formation by electrophotography or the like, a method for producing the same, and an electrostatic charge image developer using the electrophotographic toner.

  A method of 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 developed on a photoreceptor through a charging process, an exposure process, and the like, and the electrostatic image is visualized through a transfer process, a fixing process, and the like.

  In electrophotography, the electrostatic image is developed on the photoreceptor by a charging process, an exposure process, etc., and the toner on the fixing substrate after the transfer process is melted by being heated by a fixing member heated in the fixing process. Then, it is fixed on the surface of the fixing substrate. In the fixing step, it is known that the toner is not fixed onto the fixing base unless not only the toner but also the fixing base is heated to a necessary temperature by the fixing member. If the fixing substrate is not sufficiently heated, only the toner is melted by the heating from the fixing member, and a so-called cold offset is generated in which the toner adheres to the fixing member. In addition, when the heating is excessive, the viscosity of the toner decreases, and so-called hot offset occurs in which a part or all of the fixing layer adheres to the fixing member side. Therefore, a fixing region is required in which neither the cold offset nor the hot offset occurs due to heating from the fixing member.

On the other hand, as the demand for energy saving increases, it is necessary to lower the fixing temperature of the toner in order to save power in the fixing process that occupies a certain amount of power and expand the fixing area. By lowering the toner fixing temperature, in addition to the power saving and expansion of the fixing area, the waiting time until the fixing temperature on the surface of the fixing roll when power is input, so-called warm-up time is shortened, fixing The life of the roll can be extended.
However, lowering the fixing temperature of the toner also lowers the glass transition point of the toner particles at the same time, making it difficult to achieve both toner storage stability. In order to achieve both low-temperature fixing and toner storage stability, it is necessary to have a so-called sharp melt property in which the viscosity of the toner rapidly decreases in a high-temperature region while keeping the glass transition point of the toner at a higher temperature.

In general, the resin used in the toner usually has a certain range of glass transition point, molecular weight, etc., so in order to obtain the sharp melt property, it is necessary to extremely align the resin composition and molecular weight, In order to obtain the resin, it becomes necessary to adjust the molecular weight of the resin by using a special production method or by treating the resin with chromatography or the like. In this case, the cost for producing the resin must be high. In addition, unnecessary resin is generated at that time, which is not preferable from the viewpoint of environmental protection in recent years.
As a method for lowering the toner fixing temperature, it has been proposed to use a crystalline resin as a binder resin, and studies using various crystalline resins have been made (for example, see Patent Documents 1 to 19). Although these methods can lower the fixing temperature, these resins have a large inclination with respect to the temperature of the viscosity in the fixing temperature region, so that they tend to soak into the base material during fixing, and hence uneven fixing. . Furthermore, the large inclination of the viscosity with respect to the temperature means that sufficient viscosity cannot be obtained at the time of preparation of the toner, for example, during kneading, so the dispersibility of the colorant, release agent, etc. with respect to the resin is not stable, and the color developability. In addition, a toner with uneven fixing properties is easily generated, and pulverization becomes difficult, so that it is difficult to obtain a toner having a small particle diameter.
In order to solve this problem, for example, there is a method of adding an auxiliary agent such as a thickener or a grinding aid, but in that case, the auxiliary agent is dispersed in the resin and the crystallinity is lost. .

In recent years, an agglomeration method has been proposed as a means for producing a toner whose particle shape and surface composition are intentionally controlled (see, for example, Patent Document 20 or 21). In the aggregation method, a resin dispersion is prepared by a method such as emulsion polymerization or dispersion emulsification, while a colorant particle dispersion in which a colorant is dispersed in a solvent is prepared, and these are mixed to obtain a toner particle size. This is a method of forming toner particles by forming the corresponding aggregated particles and then fusing them by heating. According to this agglomeration method, the toner shape can be arbitrarily controlled from an indeterminate shape to a spherical shape by selecting the heating temperature condition.
In the agglomeration method, the resin particles are generally heated to near the glass transition temperature to partially melt the resin particle surface to easily generate agglomerated particles, and the crystalline resin is also agglomerated in the same manner. Particles can be generated. However, since the viscosity of the crystalline resin particle surface is particularly large near the melting point, the temperature range for partially dissolving the resin particle surface is narrower and the aggregation temperature is lower than that of a general amorphous resin. The agglomerated particles are unstable and fragile, and when the agglomeration temperature is high, the fusion of the particles is accelerated rapidly. For this reason, shape control, which is an advantage of the aggregation method, becomes difficult. As a result, the toner is easily spheroidized, and it is difficult to stably produce toner particles having a desired shape. Since the instability of the shape control is inversely proportional to the heat transfer performance, it becomes more remarkable as the scale for producing the toner is increased.

Another problem of the toner containing a crystalline resin is that the anti-offset property at the time of fixing due to low charge amount and low melt viscosity is insufficient. As means for solving these problems, a method has been proposed in which the above crystalline resin toner is used as a core, and a shell agent that imparts chargeability and offset resistance is coated on the core surface.
As described above, the core-shell structure improves the chargeability and offset resistance. However, in the core-shell toner manufacturing method, the core-shell toner is formed while substantially maintaining the shape of the core particles. As a result, it is difficult to stably produce a toner having a desired shape.
As a result, the toner shape tends to be spherical. When the toner shape is made spherical as described above, the cleaning property is deteriorated in the process of image formation, and there is a problem that toner filming is likely to occur on the surface of the photoreceptor.
JP 62-129867 A JP-A-62-170971 JP 62-170972 A JP 62-205365 A JP-A-62-276565 JP-A-62-276666 JP-A-63-038949 Japanese Unexamined Patent Publication No. 63-038950 Japanese Patent Laid-Open No. 63-038951 JP-A-63-038952 JP-A-63-038953 JP-A-63-038954 Japanese Unexamined Patent Publication No. 63-038955 JP 63-038956 A JP 05-001217 A Japanese Patent Laid-Open No. 06-148936 Japanese Patent Laid-Open No. 06-194874 JP 05-005056 A Japanese Patent Laid-Open No. 05-112715 Japanese Patent Laid-Open No. 63-282275 Japanese Patent Laid-Open No. 06-250439

  An object of the present invention is to solve the conventional problems in electrophotographic toners, particularly full color toners, and to achieve the following objects. That is, an object of the present invention is to provide an electrophotographic toner excellent in low-temperature fixability, high durability, good cleaning properties and transferability, a method for producing the same, and an electrostatic image developer using the electrophotographic toner. .

That is, the present invention
<1> An electrophotographic toner comprising: toner particles in which core particles containing at least a crystalline binder resin are coated with a coating agent containing an amorphous polymer; and an external additive. It is an electrophotographic toner in which the ratio of the toner particles contained is 20% or more.

  <2> The toner for electrophotography according to <1>, wherein the volume average particle diameter of the core particles is 0.3 to 0.7 times the volume average particle diameter of the toner particles.

  <3> The average value of the mass of the coating agent contained in the toner particles is 0.05 to 0.2 times the average value of the mass of the core particles contained in the toner particles. <1 > Or <2>.

  <4> The electrophotographic toner according to any one of <1> to <3>, wherein an average value of SF1 of the toner particles is 125 to 150.

  <5> The electrophotographic toner according to any one of <1> to <4>, wherein an average value of SF1 of the core particles is 100 or more and 120 or less.

  <6> The average circularity of the toner particles is 0.950 to 0.970, the 84% value of the arithmetic average height distribution is 0.15 μm to 0.25 μm, and the arithmetic average height varies. 35 or less, the loose bulk density during free flow is 0.18 g / cc or more and 0.22 g / cc or less, and the hardened bulk density is 0.35 g / cc or more and 0.42 g / cc or less <1> Or the toner for electrophotography according to any one of <5>.

  <7> The electrophotographic toner according to any one of <1> to <6>, wherein a particle size distribution of the toner particles satisfies a condition represented by the following formula (1).

D16 / D50 ≦ 1.28 (1)

(In Formula (1), D16 represents the 16% volume average particle diameter calculated from the large particle side of the volume average particle diameter of the toner particles, and D50 represents from the large particle side of the volume average particle diameter of the toner particles. (The calculated volume average particle diameter of the 50% is shown.)

  <8> The ratio of the toner particles containing a plurality of the core particles, the toner particles containing at least core particles containing a crystalline binder resin and coated with a coating agent containing an amorphous polymer, and an external additive. A method for producing an electrophotographic toner of 20% or more, wherein the coating agent-containing dispersion containing the coating agent and the core particle are mixed in an aqueous medium, and the coating agent is attached to the surface of the core particle. A coating agent attaching step, an aggregating step (toner particle precursor forming step) in which the core particles to which the coating agent is attached are aggregated to form aggregated particles (toner particle precursor), and the aggregated particles are heated. And a fusing step of fusing to form toner particles.

  <9> The method for producing an electrophotographic toner according to <8>, further comprising an inorganic fine particle attaching step of attaching inorganic fine particles to the toner particle surfaces after the fusing step.

  <10> The method for producing an electrophotographic toner according to <8>, wherein in the aggregation step (toner particle precursor forming step), inorganic fine particles are adhered to the surface of the aggregated particle (toner particle precursor).

  <11> The method for producing an electrophotographic toner according to any one of <8> to <10>, further including a drying step of drying the toner particles formed in the fusing step with a heating fluid.

  <12> The core particle is an aggregation step (core particle precursor formation step) in which a crystalline binder resin, a release agent, and a colorant particle are aggregated in an aqueous medium to form an aggregate particle (core particle precursor). ) And a fusing step of heating and fusing the agglomerated particles to form core particles, and the electrophotography according to any one of <8> to <11> This is a manufacturing method for toner.

  <13> A ratio of the toner particles containing a plurality of core particles, the toner particles including a core particle containing at least a crystalline binder resin and coated with a coating agent containing an amorphous polymer, and an external additive. An electrostatic charge image developer containing at least 20% or more of an electrophotographic toner.

  <14> The electrostatic charge image developer according to <13>, further including a carrier obtained by dispersing magnetic fine particles in a resin.

  According to the present invention, there are provided an electrophotographic toner that can be heat-fixed at a low temperature, has high durability, good cleaning properties and transferability, a method for producing the same, and an electrostatic image developer using the electrophotographic toner. be able to.

Hereinafter, the electrophotographic toner of the present invention, the production method thereof, and the electrostatic image developer using the electrophotographic toner will be described in detail.
<Toner for electrophotography>
The electrophotographic toner of the present invention contains toner particles obtained by coating core particles containing at least a crystalline binder resin with a coating agent containing an amorphous polymer, and an external additive, and includes a plurality of the core particles. The ratio of the toner particles is 20% or more. That is, the ratio of toner particles containing a plurality of core particles to all toner particles is 20% or more.

  As the crystalline binder resin used for the core particles of the present invention, all the binder resins may be crystalline resins, or a part of the binder resins may be composed of crystalline resins, The ratio of at least the crystalline resin to the entire binder resin is preferably 50% by mass or more, and more preferably 80% by mass or more. If this ratio is less than 50% by mass, the melting behavior of the resin having no crystallinity is more dominant than the sharp melt property of the binder resin, and good low-temperature fixability may not be obtained.

  In the present invention, the “crystalline resin” refers to a resin having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC).

A crystalline resin has a structure in which a plurality of units having a specific functional group such as an alkyl group are continuous, and the functional group portions are regularly arranged, whereby the molecule is easily crystallized, and is amorphous. It has a melting point as compared with the above resin and is characterized by a sharp drop in viscosity at a temperature equal to or higher than the melting point.
Although the crystalline resin has at least one melting point, high storage stability and low-temperature fixability can be ensured at the same time. That is, at a temperature lower than the melting point, the viscosity is high because the viscosity is high, and the stability at the time of image storage is excellent. When the melting point is exceeded, the viscosity is drastically lowered.

  The crystalline resin is not particularly limited as long as it is a polymerizable monomer and resin having at least one melting point and capable of constituting a crystalline resin. Specific examples include adipic acid, pimelic acid, Long chain alkyl dicarboxylic acids such as suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tridecanedioic acid; butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, batyl alcohol, etc. Polyester resins using long-chain alkyl and alkenyl diols; amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, ( (Meth) acrylic acid decyl, (meth) acrylic acid undecyl, (meth) Long chain alkyl such as tridecyl crylate, myristyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, oleyl (meth) acrylate, behenyl (meth) acrylate, etc., (meth) acrylic of alkenyl And vinyl resins using acid esters. These polymerizable monomers may be used individually by 1 type, and may use 2 or more types together.

  The crystalline resin is a compound having a short chain alkyl group, alkenyl group, aromatic ring or the like other than the above polymerizable monomer for the purpose of adjusting the melting point, molecular weight, etc. as a binder resin (for example, dicarboxylic acid, diols). Short chain alkyl vinyl polymerizable monomers, etc.) can also be used. Specific examples of the dicarboxylic acid include alkyl dicarboxylic acids such as succinic acid, malonic acid, and oxalic acid; phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, 4,4′-bibenzoic acid, and 2,6-naphthalene. Aromatic dicarboxylic acids such as dicarboxylic acid and 1,4-naphthalenedicarboxylic acid; nitrogen-containing aromatic dicarboxylic acids such as dipicolinic acid, dinicotinic acid, quinolinic acid, and 2,3-pyrazinedicarboxylic acid; Examples of the diols include short-chain alkyl diols such as succinic acid, malonic acid, acetone dicarboxylic acid, and diglycolic acid. Short chain alkyl vinyl polymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and other short chain alkyls and alkenyl ( Vinyl nitriles such as (meth) acrylic acid esters, acrylonitrile and methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; ethylene, propylene Olefins such as butadiene, isoprene, and the like. These polymerizable monomers may be used individually by 1 type, and may use 2 or more types together.

  A compound having a hydrophilic polar group can be used as long as it is copolymerizable with the crystalline resin as a resin. As a specific example, when the resin is polyester, a dicarboxylic acid compound in which a sulfonyl group is directly substituted on an aromatic ring such as sulfonyl-terephthalic acid sodium salt, 3-sulfonylisophthalic acid sodium salt, and the like are used. In the case of (meth) acrylic acid, itaconic acid and other unsaturated aliphatic carboxylic acids, glycerin mono (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, zinc mono (meth) acrylate, zinc di (meth) acrylate, 2- Esters of (meth) acrylic acid such as hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylate, and polypropylene glycol (meth) acrylate with alcohols, etc., having a sulfonyl group at any of the ortho, meta, and para positions styrene Derivatives, sulfonyl group-substituted aromatic vinyl such as sulfonyl group-containing vinyl naphthalene.

  Along with the crystalline resin, a crosslinking agent may be used as necessary for the purpose of preventing hot offset at the time of fixing in a high temperature region. Specific examples of the crosslinking agent include aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate / trivinyl, divinyl naphthalenedicarboxylate, Polyvinyl esters of aromatic polyvalent carboxylic acids such as divinyl biphenyl carboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; unsaturated heterocyclic compounds such as pyrrole and thiophene; Vinyl esters of unsaturated heterocyclic compounds such as vinyl furan carboxylate, vinyl pyrrole-2-carboxylate, vinyl thiophene carboxylate; butanediol methacrylate, hexanediol acrylate, octanediol meta (Meth) acrylic acid esters of linear polyhydric alcohols such as relate, decanediol acrylate, dodecanediol methacrylate; branches such as neopentylglycol dimethacrylate, 2-hydroxy, 1,3-diacryloxypropane, (Meth) acrylic acid esters of polyhydric alcohols; polyethylene glycol di (meth) acrylate, polypropylene polyethylene glycol di (meth) acrylates; divinyl succinate, divinyl fumarate, vinyl / divinyl maleate, divinyl diglycolate, itaconic acid Vinyl / divinyl, divinyl acetone dicarboxylate, divinyl glutarate, divinyl 3,3′-thiodipropionate, divinyl aconite / trivinyl, divinyl adipate, divinyl pimelate Suberic acid divinyl azelate, divinyl sebacate, divinyl dodecanedioate divinyl, the polyvinyl esters of polycarboxylic acids such as oxalic acid, divinyl; and the like.

In particular, when the crystalline resin is polyester, unsaturated polycarboxylic acids such as fumaric acid, maleic acid, itaconic acid, and trans-aconitic acid are copolymerized in the polyester, and then the multiple bond portions in the resin are combined. Or you may use the method of bridge | crosslinking using another vinyl type compound. These crosslinking agents may be used alone or in combination of two or more.
These cross-linking methods may be a method of polymerizing and cross-linking with a cross-linking agent during polymerization of the polymerizable monomer, or leaving the unsaturated portion in the resin and polymerizing the resin or after toner preparation. A method of crosslinking the saturated portion by a crosslinking reaction may be used.

When the crystalline resin is polyester, the polymerizable monomer can be polymerized by condensation polymerization. As the condensation polymerization catalyst, known catalysts can be used, and specific examples include titanium tetrabutoxide, dibutyltin oxide, germanium dioxide, antimony trioxide, tin acetate, zinc acetate, tin disulfide and the like. It is.
When the crystalline resin is a vinyl resin, the polymerizable monomer can be polymerized by radical polymerization. The radical polymerization initiator is not particularly limited as long as it is capable of emulsion polymerization. Specifically, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide , Ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, tetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid-tert-butyl hydroperoxide, tert-butyl formate , Peroxides such as tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl permethoxyacetate, tert-butyl perN- (3-toluyl) carbamate; 2'-azobisp Lopan, 2,2′-dichloro-2,2′-azobispropane, 1,1′-azo (methylethyl) diacetate, 2,2′-azobis (2-amidinopropane) hydrochloride, 2,2 ′ -Azobis (2-amidinopropane) nitrate, 2,2'-azobisisobutane, 2,2'-azobisisobutyramide, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2- Methyl methylpropionate, 2,2′-dichloro-2,2′-azobisbutane, 2,2′-azobis-2-methylbutyronitrile, dimethyl 2,2′-azobisisobutyrate, 1,1′-azobis (1 -Sodium methylbutyronitrile-3-sulfonate), 2- (4-methylphenylazo) -2-methylmalonodinitrile, 4,4'-azobis-4-cyanovaleric acid, 3,5-dihydroxymethylpheny Azo-2-methylmalonodinitrile, 2- (4-bromophenylazo) -2-allylmalonodinitrile, 2,2′-azobis-2-methylvaleronitrile, 4,4′-azobis-4-cyanoyoshi Dimethyl herbate, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobiscyclohexanenitrile, 2,2′-azobis-2-propylbutyronitrile, 1,1′-azobis-1 -Chlorophenylethane, 1,1'-azobis-1-cyclohexanecarbonitrile, 1,1'-azobis-1-cycloheptanenitrile, 1,1'-azobis-1-phenylethane, 1,1'-azobiscumene, 4-Nitrophenylazobenzylethyl cyanoacetate, phenylazodiphenylmethane, phenylazotriphenylmethane, 4-nitrophenylazotri Phenylmethane, 1,1′-azobis-1,2-diphenylethane, poly (bisphenol A-4,4′-azobis-4-cyanopentanoate), poly (tetraethylene glycol-2,2′-azobisiso Azo compounds such as butyrate); 1,4-bis (pentaethylene) -2-tetrazene, 1,4-dimethoxycarbonyl-1,4-diphenyl-2-tetrazene and the like. The polymerization initiator can also be used as an initiator for a crosslinking reaction in the crosslinking step.

In the electrophotographic toner of the present invention, a colorant is used to obtain each desired color. For this reason, it is preferable to contain at least one selected from cyan, magenta and yellow pigments as the colorant. One type of pigment may be used alone, or two or more types of pigments of the same type may be mixed and used. Two or more different types of pigments may be mixed and used.
Examples of the colorant include chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, and dupont oil. Various pigments such as red, pyrazolone red, resol red, rhodamine B lake, lake red C, rose bengal, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxalate; acridine , Xanthene, azo, benzoquinone, azine, anthraquinone, dioxazine, thiazine And the like; azomethine, indigo, thioindigo, phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, thiazole type, various dyes such as xanthene. You may mix black pigments, such as carbon black, and dye to such an extent that transparency is not reduced to these colorants.

  Although there is no restriction | limiting in particular as content of a coloring agent, What is necessary is just about 50 mass% or less, and it is preferable that it is about 2-40 mass%.

  Other additives such as a release agent can be added to the electrophotographic toner of the present invention as necessary. Specific 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-based wax. These release agents may be used alone or in combination of two or more.

  The release agent preferably has at least one melting point in the temperature range of 45 to 110 ° C. from the viewpoint of preventing hot offset due to the release of the release agent in the fixing temperature range. The release agent preferably has a melting point of 45 to 110 ° C, more preferably 50 to 100 ° C, and still more preferably 55 to 90 ° C. When the melting point is lower than 45 ° C., the storage stability of the toner may be difficult, and when it exceeds 110 ° C., the melting point is too high and low-temperature fixing may be difficult.

  The addition amount of the release agent is preferably 0.5 to 50% by mass, more preferably 0.5 to 40% by mass, further preferably 1 to 30% by mass, and particularly preferably 5 to 15% by mass. It is. If the amount is less than 0.5% by weight, the effect of adding a release agent may not be obtained. If the amount is 50% by weight or more, the chargeability is likely to be affected, or the toner is easily destroyed inside the developing machine. In addition to the effect that the release agent is spent on the carrier and the charge is likely to decrease, for example, when color toner is used, the image surface tends to be insufficiently oozed out during fixing. In some cases, the release agent tends to stay in the image, which is not preferable because the transparency tends to deteriorate.

  Amorphous polymers contained in the coating agent include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, acrylic acid 2 -Esters having a vinyl group such as ethylhexyl, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl methyl ether, Vinyl ethers such as vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; polymers comprising monomers such as polyolefins such as ethylene, propylene and butadiene, or the like A copolymer obtained by combining two or more of these, or a mixture thereof, and further, an epoxy resin, a polyester resin, a polyurethane resin, a polyamide resin, a cellulose resin, a polyether resin, and the like, a non-vinyl condensation resin, or these and the vinyl resin And a graft polymer obtained by polymerizing a vinyl monomer in the presence of these.

  When a vinyl monomer is used, emulsion polymerization or seed polymerization can be carried out using an ionic surfactant or the like to prepare a resin particle dispersion. When using other resins, the resin is oily and water-soluble. Dissolve the resin in a solvent with relatively low solubility, disperse the fine particles in water with a disperser such as a homogenizer in the presence of an ionic surfactant or polymer electrolyte in water, and then heat or reduce the pressure to evaporate the solvent. As a result, a desired resin dispersion can be prepared.

  Examples of other internal components include internal additives, charge control agents, inorganic particles, organic particles, lubricants, and abrasives depending on the purpose. The internal additive can be used in such an amount that does not hinder the chargeability as a toner characteristic, for example, ferrite, magnetite, reduced iron, cobalt, manganese, nickel and other metals, alloys, compounds containing these metals, etc. And magnetic materials. Moreover, it is desirable to add the internal additive to either or both of the core layer and the shell layer depending on the application. The charge control agent is not particularly limited, but when a color toner is used, a colorless or light-colored agent can be preferably used. Examples thereof include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments. The content of these other internal additives may be a level that does not hinder the object of the present invention, and is generally a very small amount, specifically about 0.01 to 5% by mass, 0 About 0.5 to 2% by mass is preferable, and about 0.5 to 2% by mass is more preferable.

The electrophotographic toner of the present invention is obtained by adding an external additive such as a fluidizing agent or an auxiliary agent to the toner particle surface. External additives include known fine particles such as silica fine particles, titanium fine particles, alumina fine particles, cerium oxide fine particles, carbon black and other inorganic fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate and silicone resin. Of these, at least two or more types of external additives are used, and at least one of the external additives has an average primary particle diameter (volume average particle size of 30 nm to 200 nm, more preferably 30 nm to 180 nm. (Diameter).
As the toner particle size is reduced, non-electrostatic adhesion to the photoconductor increases, which causes transfer defects and image loss called hollow characters, and causes uneven transfer such as superimposed images. Therefore, it is preferable to add a large external additive having an average primary particle diameter of 30 nm to 200 nm to improve transferability. If the average primary particle diameter is less than 30 nm, the initial toner fluidity is good, but the non-electrostatic adhesion between the toner and the photoreceptor cannot be sufficiently reduced, resulting in a decrease in transfer efficiency and loss of image. In addition, the uniformity of the image is deteriorated, and the fine particles are embedded in the toner surface due to the stress in the developing device over time, and the charging property is changed to cause problems such as a decrease in copy density and fogging on the background portion. On the other hand, if the average primary particle diameter is larger than 200 nm, the particles are easily detached from the toner surface and the fluidity is deteriorated. The content of these external additives may be a level that does not hinder the object of the present invention, and is generally a very small amount, specifically about 0.01 to 5% by mass, 0.5 To about 3 mass% is preferable, and about 1.0 to 2.5 mass% is more preferable.

  The electrophotographic toner of the present invention preferably has a melting point of 45 to 110 ° C, more preferably 50 to 100 ° C, and still more preferably 55 to 90 ° C. If the melting point is lower than 45 ° C., the storage stability of the toner may be difficult, and if it exceeds 110 ° C., the effect on low-temperature fixing may be reduced. The melting point of the resin can be determined by the method shown in JISK-7121.

  In the electrophotographic toner of the present invention, the melting point of the toner is Tm, and the loss tangent tan δ at Tm + 20 ° C. preferably satisfies 0.01 ≦ tan δ ≦ 2 at an angular frequency of 1 rad / sec. When the loss tangent tan δ satisfies the above range, excessive penetration of the fixing substrate such as paper can be prevented, and at the same time, the temperature range where fixing can be performed can be expanded.

The toner for electrophotography of the present invention is obtained by, for example, fusing a plurality of core shell particles with a coating agent (shell) as shown in FIGS. 1 and 2, or fusing a part of the core particles as shown in FIG. And the like. Further, it may be a core-shell toner composed of a plurality of spherical core particles as shown in FIGS. 1 and 3, or a core-shell toner composed of a plurality of core particles having different particle sizes and shapes as shown in FIG. . In particular, when core particles having a wide particle size and shape distribution are present as shown in FIG. 2, it is possible to reduce variations in the shape and particle size distribution by, for example, covering the shell with an agglomeration method.
In the electrophotographic toner of the present invention, the ratio of the toner particles containing a plurality of the core particles is required to be 20% or more, preferably 40% by mass or more, and preferably 60% by mass or more. It is particularly preferred. If the ratio of the toner particles containing a plurality of core particles is less than 20% by mass, there may be a problem in cleaning properties.
In the present invention, the cross-section of the toner particles is observed with a TEM, and the ratio of the toner particles containing a plurality of core particles in 100 toner particles is defined as the ratio of the toner particles including a plurality of core particles.

The volume average particle size of the electrophotographic toner of the present invention is preferably 3 to 10 μm from the viewpoint of obtaining high image quality. If it is larger than 10 μm, the reproducibility of fine lines is inferior in the development process, so that the image quality is lowered, and if it is less than 3 μm, the life of the developer tends to be shortened, which is not preferable.
At this time, the volume average particle diameter of the core particles contained in the toner particles is preferably 0.3 to 0.7 times the volume average particle diameter of the toner particles. More preferably, it is 0.4 to 0.7 times. By controlling in the range of 0.3 times to 0.7 times, an irregular shaped toner having a large curvature can be easily obtained. By making the toner particles irregular, it becomes possible to dramatically improve the cleaning property. Further, since the uneven surface has a large curvature, it is easy to be transferred and the toner has good transferability. When the average particle diameter of the core particles is less than 0.3 times that of the toner particles, the curvature of the concavo-convex surface becomes small, and the effect of improving transferability is lowered, which is not preferable. On the other hand, when it exceeds 0.7 times, the amount of toner particles containing a plurality of core particles decreases, and the cleaning effect improving effect of the present invention is reduced, which is not preferable. On the other hand, when it is less than 0.4 times, the core particle diameter is decreased, and the low-temperature fixing property of the core particles is deteriorated. Further, by setting the core particle size to 0.7 times or less, the strength of the toner base particles is improved, and the external additive is hardly buried, and a toner having high temporal stability can be obtained.

The average value of the mass of the coating agent contained in the toner particles is preferably 0.05 to 0.2 times the average value of the mass of the core particles contained in the toner particles. If it is less than 0.05 times, the coating of the core particles with the coating layer is not sufficiently performed, and the charging effect due to the core shell formation and the effect of improving the offset resistance are reduced. This is not preferable because the low-temperature fixability characteristics of the core particles are impaired.
The average value of SF1 of the toner particles is preferably 125 or more and 150 or less. If the average value of SF1 is less than 125, it is not preferable because a cleaning failure is likely to occur during blade cleaning. On the other hand, if it exceeds 150, transferability deteriorates, which is not preferable.

As for the shape distribution of the toner particles, the narrower the distribution, the more easily the effect of the present invention on the transferability and cleaning properties can be achieved, and the standard deviation of the number-based SF1 shape distribution is preferably less than 10.
Furthermore, the average value of SF1 of the core particles is preferably 100 or more and 120 or less. Use of a core having an SF1 exceeding 120 is not preferable because the toner particle surface resistance increases and transferability deteriorates. Conversely, the closer the core particles contained in the toner particles are to the sphere, the lower the surface resistance of the toner particles and the better the transferability.

The surface area of the electrophotographic toner of the present invention is not particularly limited and can be used as long as it can be used for a normal toner. Specifically, when the BET method is used, it is about 0.5 to 10 m ² / g, preferably about 1.0 to 7 m ² / g, more preferably about 1.2 to ⁵ m ² / g.
The absolute value of the charge amount of the electrophotographic toner of the invention is preferably 10 to 40 μC / g, and more preferably 15 to 35 μC / g. If the absolute value of the charge amount is less than 10 μC / g, background stains tend to occur, and if it exceeds 40 μC / g, the image density tends to decrease. The ratio of the charge amount in summer (30 ° C./90% RH) and the charge amount in winter (10 ° C./10% RH) is preferably 0.5 to 1.5, and preferably 0.7 to 1.3. Is more preferable. When the ratio is out of the above range, the toner is highly dependent on the environment and the charging property is not stable, which is not preferable in practice.

It is preferable to add 2 to 10% by mass of inorganic fine particles having a number average particle diameter of 10 nm to 100 nm on the surface of the toner particles. As a result, a uniform inorganic fine particle layer is formed on the outermost surface, and as a result, a toner having excellent durability and good charge retention can be obtained.
When the added amount of the inorganic fine particles is less than 2% by mass, the charge is liable to leak, so that the charge maintainability is lowered. On the other hand, if the amount of inorganic fine particles added exceeds 10% by mass, the low-temperature fixing effect may be impaired. Further, when the volume average particle diameter of the inorganic fine particles exceeds 100 nm, the outermost inorganic fine particles are liable to be detached due to machine stress, resulting in a decrease in charge maintenance and filming due to the desorbed inorganic fine particles. On the other hand, when the thickness is less than 10 nm, the aggregation of the inorganic fine particles is large, and it becomes difficult to form a uniform inorganic fine particle layer, and the charge maintenance property is lowered.
As the inorganic fine particles used in the present invention, known inorganic fine particles such as silica fine particles, titanium oxide fine particles, alumina fine particles, and cerium oxide fine particles whose surface has been subjected to a hydrophobic treatment can be used.

  The particle size distribution of the toner particles preferably has a narrow distribution on the large particle size side in the volume average particle size. The index is shown by the following formula (1).

  D16 / D50 ≦ 1.28 (1)

  In Formula (1), D16 represents the 16% volume average particle diameter calculated from the large particle side of the volume average particle diameter of the toner particles, and D50 is calculated from the large particle side of the volume average particle diameter of the toner particles. The volume average particle size of the 50th is shown.

When the index is greater than 1.28, there are many toners called so-called medium powder and coarse powder on the large particle diameter side of the volume average particle diameter. Medium powder and coarse powder not only cause image defects due to scattering of the toner, but also cause the toner to be crushed by mechanical collision with the carrier, generating fine powder and causing poor cleaning. For this reason, it is preferable that the amount of medium powder / coarse powder is small.
The volume average particle diameter can be measured, for example, by measuring with a 100 μm aperture diameter using a Coulter counter [TA-II] type (manufactured by Coulter). At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (Isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

The toner particles have an average circularity of 0.950 or more and 0.970 or less, an 84% value of the arithmetic average height distribution is 0.15 μm or more and 0.25 μm or less, and the variation of the arithmetic average height is 35. The loose bulk density during free flow is preferably 0.18 g / cc or more and 0.22 g / cc or less, and the hardened bulk density is preferably 0.35 g / cc or more and 0.42 g / cc or less.
When the loose bulk density is less than 0.18 g / cc and when the hardened bulk density is less than 0.35 g / cc, the colorant and the release agent are not contained as desired, and the mixture is stirred and mixed with the carrier. In some cases, mixing may be poor, causing image density reduction and toner scattering. Further, when the loose bulk density is larger than 0.22 g / cc or when the solid bulk density is larger than 0.42 g / cc, the volume average particle diameter of the toner particles is smaller than the desired particle diameter, or the toner average In many cases, the circularity is larger than 0.970, which is not preferable.

  Regarding the loose bulk density and the hard bulk density, for example, using a powder tester [PT-R] type (manufactured by Hosokawa Micron Co., Ltd.) until the free-flowing toner is dropped in a container having a known volume and spills. After filling and allowing to stand for 1 minute, excess toner is removed, and the quotient of the weight of the toner filled in the container and the volume of the container is loosened to obtain a bulk density. Further, a free-flowing toner is further added to a container in which the toner is densely packed, and after tapping 180 times, the quotient of the weight of the toner filled in the container and the container volume is solidified to obtain a bulk density.

The toner for electrophotography of the present invention is desired to have sufficient hardness at room temperature. Specifically, the dynamic viscoelasticity is that the storage elastic modulus GL (30) is 1 × 10 ⁶ Pa or more and the loss elastic modulus GN (30) is 1 × 10 ^{6 at} an angular frequency of 1 rad / sec and 30 ° C. It is desirable that it is ⁶ Pa or more. The storage elastic modulus GL and the loss elastic modulus GN are stipulated in JIS K-6900.
If the storage elastic modulus GL (30) is less than 1 × 10 ⁶ Pa or the loss elastic modulus GN (30) is less than 1 × 10 ⁶ Pa at an angular frequency of 1 rad / sec and 30 ° C., the carrier in the developing machine When mixed with the toner, the toner particles may be deformed by the pressure or shearing force received from the carrier, and stable charge development characteristics may not be maintained. Further, when the toner on the latent image carrier (photoconductor) is cleaned, it may be deformed by the shearing force received from the cleaning blade, resulting in poor cleaning.
When the storage elastic modulus GL (30) and the loss elastic modulus GN (30) are within the above ranges at the angular frequency of 1 rad / sec and 30 ° C., the characteristics during fixing are stable even when used in a high-speed electrophotographic apparatus. It is preferable.

Furthermore, the electrophotographic toner of the present invention has a temperature interval in which the values of the storage elastic modulus GL and the loss elastic modulus GN due to temperature change are two digits or more in a temperature range of 10 ° C. It is preferable to have a temperature interval in which the values of GL and GN change to values of 1/100 or less when raised. If the storage elastic modulus GL and the loss elastic modulus GN do not have the temperature section, the fixing temperature increases, and as a result, it may be insufficient to reduce the energy consumption of the fixing process.
Further, when the common logarithm of the storage elastic modulus is plotted against the temperature, the electrophotographic toner of the present invention has a storage elastic modulus at a temperature (Tm + 20 ° C.) 20 ° C. higher than the melting point Tm, from GL (Tm + 20) and the melting point Tm. When the storage elastic modulus at a temperature higher by 50 ° C. (Tm + 50 ° C.) is GL (Tm + 50), the melting point Tm is satisfied when the following formula (2) is satisfied and the common logarithm of the loss elastic modulus is plotted against the temperature. When the loss elastic modulus at a temperature 20 ° C. higher (Tm + 20 ° C.) is GN (Tm + 20) and the loss elastic modulus at a temperature 50 ° C. higher than the melting point Tm (Tm + 50 ° C.) is GN (Tm + 50), It is preferable to satisfy the above condition in order to reduce non-uniformity of image gloss caused by temperature distribution or the like depending on the image part.

| Log GL (Tm + 20) −log GL (Tm + 50) | ≦ 1.5 (2)

| Log GN (Tm + 20) −log GN (Tm + 50) | ≦ 1.5 (3)

  This index indicates that the viscosity of the electrophotographic toner of the present invention has a moderate dependence on temperature after the melting point, and means that the temperature dependence of viscoelasticity becomes lower.

  Since the electrophotographic toner of the present invention has the above-described configuration, it is excellent in toner blocking resistance, image storage stability, and low-temperature fixability.

By controlling the arithmetic average height of the toner particles and making the surface fine uneven structure of the toner particles small and uniform, the uneven distribution of the external additive can be further suppressed, and the uniform spacer effect of the external additive can be reduced. The toner is solidified by long-term storage, and the friction between the toner and the toner agitating member due to the toner conveying force from the toner cartridge is mitigated, thereby enabling stable toner supply.
When the median arithmetic average height of the toner particles is less than 0.05 μm, the surface effect of the external additive becomes small because the fine surface uneven structure of the toner is small. When the median arithmetic average height of the toner is greater than 0.12 μm, the external additive is easily embedded in the roughness of the toner surface fine concavo-convex structure, and the spacer effect of the external additive is efficient. In other words, the transfer efficiency decreases.

The variation in arithmetic average height represents the distribution of arithmetic average height, and a smaller value means that the distribution becomes narrower. When the variation of the arithmetic average height is larger than 35, the uneven distribution of the toner surface roughness becomes large, and thus the external additive adhesion state on the toner surface is not uniform.
In order to realize such a toner structure, the median of the arithmetic average height of the toner particles is controlled to 0.03 μm or more and 0.10 μm or less, and at least the volume conversion median diameter is 0.1 μm or more and less than 0.3 μm. It is preferable to attach the external additive to the toner particles. When the median arithmetic average height of the toner particles is less than 0.03 μm, the surface of the toner particles is smooth, so the adhesion of the external additive is weak and the adhesion state is difficult to stabilize. On the other hand, if the median arithmetic mean height of the toner particles is larger than 0.10 μm, the external additives are likely to be unevenly distributed in the concave portions of the toner particles, making it difficult to obtain a stable external additive adhesion state. Further, when the arithmetic average height of the toner particles is controlled to be 0.03 μm or more and 0.10 μm or less, in order to realize this arithmetic average height, at least the volume-converted median diameter of the external additive is 0.1 μm or more and 0.000. It is preferable to attach an external additive of less than 3 μm. When the volume-converted median diameter of the external additive exceeds this range, it becomes difficult to realize toner particles having an arithmetic average height of 0.05 μm or more and 0.12 μm or less.

  The 84% value of the arithmetic average height distribution of the toner particles is preferably 0.15 μm or more and 0.25 μm or less. When the 84% value of the arithmetic average height distribution is in the above range, it is possible to maintain the uniform charge amount over a long period of time by embedding the external additive by contact between the toners.

Here, the arithmetic average height of the toner particles is a physical quantity which is a surface roughness index and is generally expressed as Ra.
Ra is a value obtained by extracting a reference length from the roughness curve of the toner surface in the direction of the average line, and summing and averaging the absolute values of deviations from the average line of the extracted portion to the measurement curve. When the surface is smooth, a large value indicates a state with a large surface.

The arithmetic average height of the toner was measured with an ultra-deep color 3D shape measuring microscope VK-9500 manufactured by Keyence Corporation. In this apparatus, a sample is irradiated with a laser to perform three-dimensional scanning. The laser reflected light at each position is monitored with a CCD camera to obtain three-dimensional surface information of the sample. The obtained surface information is statistically processed to obtain an index related to the surface roughness.
Here, the measurement was repeated over 1000 toner particles, the data was statistically processed to obtain the arithmetic average height distribution of the toner particles, and data such as the average value, median value, and standard deviation of the arithmetic average height were obtained. .
The variation in the arithmetic average height is a percentage of the standard deviation with respect to the average arithmetic average height. When the variation of the arithmetic average height of the toner particles is 35 or less, it means that the difference in the area of the toner particles contacting the photoreceptor, the intermediate transfer body, etc. decreases between the toners. Can be controlled.
The variation of the arithmetic average height is more preferably 30 or less, and particularly preferably 25 or less.

The number average particle size variation of the toner particles in the present invention is preferably 25 or less, and more preferably 20 or less. When the number average particle diameter variation is large, it means that the size difference between the small diameter toner particles and the large diameter toner particles becomes large, and the difference in surface area per toner particle becomes large. Since the surface charge density of the toner in the developing device corresponds to the surface area, the difference in surface area per toner particle appears as a difference in charge amount per toner particle.
Therefore, when the number average particle size variation is greater than 25, the difference in charge amount per toner particle increases. Since the optimum transfer electric field differs for each toner particle due to the difference in charge amount, it is difficult to transfer toner particles having different charge amounts simultaneously under one transfer condition and with very high efficiency. It becomes.
The number average particle size variation is a value obtained by performing statistical processing on the measured value of the number average particle size DTN for a certain number of toner particles and expressing the standard deviation as a percentage with respect to the average value.

The average circularity of the toner particles in the present invention is preferably 0.950 or more and 0.970 or less. Further, the variation in the circularity of the toner particles is preferably 0.25 or less, and more preferably 0.20 or less.
The average circularity is 1.000 when the average circularity is, and the lower the numerical value, the greater the irregularity. When the average circularity is less than 0.950, the irregular shape of the toner shape becomes too large, and the transfer efficiency is lowered. In addition, the fineness of image quality may be reduced, and fine powder may be generated due to toner cracks or chipping. On the other hand, when the average circularity exceeds 0.970, the toner shape approaches a spherical shape, so that the cleaning properties of the photosensitive member, intermediate transfer member, and the like using blade cleaning deteriorate.
Here, the average circularity is a value obtained by performing an image analysis on a certain number of toner particles, obtaining the circularity for each photographed toner particle by the following formula (4), and averaging them. The circularity variation is obtained by performing statistical processing on each circularity thus obtained and expressing the standard deviation with respect to the average value as a percentage.

Circularity = circle equivalent diameter perimeter / perimeter = 2A1 / 2π / PM (4)

  In formula (4), A1 represents the projected area of the particle, and PM represents the perimeter of the particle.

  The number average particle diameter, number average particle diameter variation, average circularity, and circularity variation of the toner particles are measured for each of 5000 toner particles using a flow type particle image analyzer FPIA-2100 (manufactured by Sysmex). Analysis was performed and statistical processing was performed.

<Method for producing electrophotographic toner>
The method for producing the toner for electrophotography of the present invention is not particularly limited, and any one or some of known production methods can be applied in combination. As a known production method, for example, as a dry toner production method, a binder resin is melt-kneaded together with a release agent such as a pigment, a charge control agent, and wax, cooled, finely pulverized and classified, and kneading freezing. Examples thereof include a pulverization method. As a wet toner manufacturing method, a resin fine particle dispersion and a colorant dispersion are mixed and heated to a temperature above the glass transition point or melting point of the resin to melt and coalesce the aggregated particles to form toner particles. Aggregation method (for example, Japanese Patent Application Laid-Open No. 63-25664), a method in which a molten toner is sheared and stirred in an insoluble liquid to form fine particles, a binder resin and a colorant are dispersed in a solution and jet spraying is performed. Examples thereof include a method for forming fine particles. Among these, the aggregation coalescence method is desirable.
Specifically, a coating agent adhesion step in which the coating particle dispersion containing the coating agent and the core particles are mixed in an aqueous medium to adhere the coating agent to the surface of the core particles; and An aggregating step (toner particle precursor forming step) for aggregating the attached core particles to form agglomerated particles (toner particle precursor); and fusing for heating and aggregating the agglomerated particles to form toner particles And at least a process.

Hereinafter, the aggregation coalescence method will be described in detail.
Aggregation and coalescence is a method in which resin particles are prepared by stirring and dispersing various resin materials in a medium or by emulsion polymerization, for example, and particles comprising a colorant (hereinafter referred to as “colorant particles”), separation, if necessary. This is a so-called agglomeration method in which heteroaggregation is performed together with a dispersion of other components such as a mold agent, and then fused to obtain toner particles. The agglomeration method can be applied to both the production process of the core particles and the coating agent attaching process to the core particles.
By applying the aggregation method to the core particle preparation step, core particles having a smooth surface and a narrow particle size distribution can be prepared.

  In addition, by applying an agglomeration method to the coating agent attaching step, a coating film having a uniform thickness can be formed on the surface of the core particles, and a core-shell toner including a plurality of core particles as in the present invention is produced. Even in this case, the particle size distribution of the toner particles can be narrowed, and the desired shape can be easily controlled. In addition, as another effect of applying the agglomeration method to the coating agent adhesion step, for example, when using core particles with relatively irregular shapes and particle sizes, which are produced by another manufacturing method such as a pulverization method or a spray drying method, etc. In addition, it becomes possible to produce toner particles having a narrow shape and particle size distribution in the coating agent attaching step.

The core particles are formed by aggregating a crystalline binder resin, a release agent, and colorant particles in an aqueous medium to form aggregated particles (core particle precursor); It is preferable that the agglomerated particles are obtained through at least a fusing step of heating and fusing the aggregated particles to form core particles.
In the core particle preparation step by the aggregation method, in the liquid, the crystalline resin particles and other additives such as colorant particles and release agents are mixed as necessary, and each particle aggregates. Agglomerated particles are formed. Here, each raw material particle is desirably dispersed to a desired dispersion state so that there is no variation among the produced aggregated particles and a desired function can be expressed. The particles agglomerated in the agglomeration step are melted at a temperature condition equal to or higher than the melting point of the resin in the agglomerated particles or the glass transition point in the fusing step, whereby the resin in the agglomerated particles is fused to form core particles. Is done.

  In addition, in the coating agent attaching step by the agglomeration method, the core particles, the coating agent particles, and other additives as necessary are mixed in the liquid, and the coating agent particles are first attached to the surface of the core particles, and then the coating is performed. The particles are aggregated to obtain a desired particle size. By gradually melting the particles aggregated in this aggregation step under a temperature condition near the glass transition point of the resin contained in the coating agent in the aggregated particles in the fusion step, the resin in each aggregated particle becomes The toner particles are formed by fusing. In the fusion process, the core particles may be partially fused.

The toner particles obtained through the fusing process exist as a dispersion in the aqueous medium, and at the same time, the toner particles are removed from the aqueous medium in the washing process, and at the same time, impurities generated in each process are removed. Then, it is dried in the drying step, an external additive is added in the external addition step, and coarse particles are removed in the sieving step to obtain an electrophotographic toner.
As a means for dispersing the raw material particles in these toner production methods, a rotary shear type homogenizer, a ball mill having a media, a sand mill, a dyno mill, a DCP mill, a spike mill, a forced collision type optimizer (manufactured by Sugino Machine Co., Ltd.), etc. A typical disperser can be used.

For aggregation, a general jacketed stirring tank or the like is used. As the stirring blades, conventionally known stirring blades such as paddle blades and turbine blades are used. Further, as the material of the stirring tank wall surface, stainless steel (SUS304, SUS316, etc.), a buffed and / or electrolytically polished one, a glass lining treatment or a Teflon (registered trademark) lining treatment, etc. are preferably used. . Moreover, you may install a baffle in a tank. For the fusion, a similar jacketed stirring tank or the like is preferably used. For example, it may be continuously fused through a tubular heat exchanger or a heat exchanger having a static mixer or a forced stirring blade therein. After fusing, it is preferable to cool at a desired rate after fusing in order to adjust the crystalline state of the crystalline binder resin.
Coarse particles may be removed from the fused toner slurry by, for example, a circular vibrating sieve or a filter bag.

  The toner slurry can be washed by, for example, a method of repeatedly filtering the slurry and returning it to water, a method of creating a cake layer with a filter press, a belt filter, or the like and forcing water to pass through the cake layer. A combined method or the like is used, and in some cases, the toner particles may be put into an acid or (and) alkali solution and washed in the middle of washing.

Further, the method for producing the electrophotographic toner of the present invention is not particularly limited, but as a means for attaching the inorganic fine particles, a method in which the inorganic fine particles are attached to the surface of the toner particles and then dried by a heating fluid. Is desirable.
After attaching inorganic fine particles to the toner particle surface and drying with a heating fluid, many inorganic fine particles are embedded in the shell layer and fixed when the fusion of the shell layer is promoted by thermal stress during drying It is possible to form a strong coating layer, and the effect of inorganic fine particles not embedded in the shell layer reduces the cohesive force between toner particles, and uniformly applies heat and fluid stress to individual toner particles. It becomes possible to do. Further, since the surface layer of the toner particles is covered with inorganic fine particles, the heat resistance of the surface is improved, and even when the temperature of the hot air is high to some extent, coarse particles due to a fusion product or an aggregate are hardly formed.

Usually, the polymerized toner is preferably dried with a heating fluid using a vacuum dryer, a freeze vacuum dryer, a shelf dryer, a vibrating fluidized bed dryer, a hot air dryer such as a flash jet dryer, or the like. For example, when using a dryer that does not use heat or fluid, such as a vacuum dryer, the effect of attaching and immobilizing inorganic fine particles cannot be obtained.
In addition, about the moisture content after drying, it is desirable to set it as the range of 0.1-1.0 mass%. When the water content exceeds 1.0% by mass, the charge of the toner is greatly reduced, which causes development and transfer failure. Also, a moisture content of 0.1% or less is not preferable because a very large amount of heat and fluid energy is used to reach the target and productivity is also lowered. Considering the balance of productivity, cost, and quality, the moisture content is preferably controlled to 0.2% to 0.6%.

In addition, after drying with a hot air dryer, the drying of the hot air current is performed again to further promote the fixation of the inorganic fine particles. In this case, it is preferable that the moisture content after drying in the former stage is 0.2% or more and 15% or less and the latter stage is dried. By setting the moisture content to 15% by mass or less, the cohesive force between the particles decreases, and it becomes possible to more uniformly apply heat and fluid energy during subsequent drying. On the other hand, if it is 0.2% or less, the latent heat of vaporization is reduced, which causes coarse particles due to fusion in the apparatus and fusion between toners during subsequent drying.
Further, the temperature and the amount of hot air used for drying are preferably set so that the average temperature of the toner particles after drying is equal to or lower than the glass transition temperature of the coating layer. When the average temperature of the toner particles exceeds the glass transition temperature of the coating layer, aggregation between the toner particles and fusion in the apparatus are not preferable. The average temperature of the toner particles after drying is preferably set to a glass transition temperature of the shell layer of −20 ° C. or higher. By doing so, it is possible to obtain a moderate shell layer fusion promoting effect.

As the means for adding the inorganic fine particles, they may be mixed before being dried, but a method of adding the inorganic fine particles to the toner particles in a slurry state is suitable for uniformly adhering to the surface. For example, by adding inorganic fine particles and a surfactant, a flocculant or the like as appropriate to a slurry in which the shell layer is coated by an agglomeration method, the inorganic fine particles uniformly adhere to the shell layer surface.
The timing of adding the inorganic fine particles may be after the shell particles are fused or during the fusion. That is, after the fusing step, an inorganic fine particle attaching step for attaching inorganic fine particles to the toner particle surface may be further included. In the aggregating step (toner particle precursor forming step), the aggregated particles (toner particles) Precursor) Inorganic fine particles may be attached to the surface.
The dryer used in the present invention is not particularly limited except that it is dried by bringing the heated fluid and wet powder into contact with each other. FIG. 4 shows an example of the drying equipment preferably used in the present invention. .

The wet powder flows into the dryer 11 through the valve 12 from the supply port 13. The heating fluid is gas taken in through the filter 17 as heating fluid through the heat exchanger 16, introduced into the chamber 14, and flows into the dryer through the nozzle 15. The nozzle 15 is inclined in one direction, and the discharged heated fluid rotates at high speed in the dryer. The swirling flow is accompanied by a wetting fluid. Thereafter, the dried powder passes through the dryer outlet 21 by the suction force of the blower 20, is collected by the dust collector 18, and is discharged from the damper 19.
It is desirable to adjust the temperature and flow rate of the heating fluid based on the temperature of a thermometer (not shown) installed at the dryer outlet 21. As the dryer 11, it is preferable to use a flash jet dryer.
Moreover, you may adjust the humidity of a heating fluid as needed.
As the external addition step, a conventionally known mixing device such as a Henschel mixer, a super mixer, a cyclomix, or a nauta mixer can be used.
For the dry sieving, a wind sieving machine, a circular vibrating sieve, a gyro shifter, an ultrasonic vibrating sieve, a turbo screener, or the like is used, and a mesh having an opening of 25 to 300 μm is preferably used.

  In the method for producing an electrophotographic toner of the present invention, the aggregation step is usually performed using each particle dispersion solution in which each material (particle) is dispersed in a dispersion. Since aggregation due to thermal motion aggregation may easily occur, the resin particle dispersion is preferably stored at a temperature of 40 ° C. or lower. More preferably, it is 20 degrees C or less. When stored at a temperature higher than 40 ° C., it may be necessary to disperse the agglomerated particles at the time of dispersion, and not only dispersion uniformity cannot be ensured, but also unnecessary energy for agitation of the agglomerates may be required. This is not preferable. In the case where the crystalline resin particles are formed by emulsifying the crystalline resin, if the dispersion is performed at a temperature equal to or higher than the melting point of the crystalline resin, the viscosity of the crystalline resin is lowered. Can be obtained. Furthermore, when producing crystalline resin particles by emulsion polymerization of crystalline resins, hydrophobic groups such as surfactants do not enter the interior of the resin particles, so they can be removed during washing, affecting the chargeability. Since it is difficult to give, it is possible to add an emulsifier such as a surfactant.

  In the method for producing an electrophotographic toner of the present invention, the crystalline binder resin particle dispersion and other resin dispersions, and dispersions of other components such as colorant particles and a release agent are dispersed and stabilized. Is preferred. Crystalline binder resin particle dispersions and other resin dispersions can be used as they are, but dispersions of other components such as colorant particles and release agents are difficult to disperse as they are, and A slight amount of a surfactant can be used for reasons of the temporal stability of the crystalline binder resin particle dispersion and other resin dispersions.

  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 glycol And nonionic surfactants such as polyphenols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, an ionic surfactant is preferable, and an anionic surfactant and a cationic surfactant are more preferable. In particular, anionic surfactants generally have a strong dispersing power and are excellent in the dispersion of resin particles and colorants. Therefore, a cationic surfactant is advantageous as a surfactant for dispersing a release agent. It is. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. These surfactants may be used alone or in combination of two or more.

  Specific examples of anionic surfactants include fatty acid soaps such as potassium laurate and sodium oleate castor oil; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, and nonylphenyl ether sulfate; lauryl sulfonate, Sulfone such as sodium alkylnaphthalene sulfonate such as dodecylbenzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate, naphthalene sulfonate formalin condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate, lauric acid amide sulfonate, oleic acid amide sulfonate Acid salts; lauryl phosphate, isopropyl phosphate, nonylphenyl ether phosphate Phosphoric acid esters such as Eto; dialkyl sulfosuccinate salts such as sodium dioctyl sulfosuccinate, sulfosuccinic acid salts, such as sodium lauryl sulfosuccinate 2; and the like.

  Specific examples of the cationic surfactant include laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, stearylaminopropylamine acetate, and other amine salts; lauryltrimethylammonium chloride, dilauryldimethylammonium Chloride, distearyl ammonium chloride, distearyl dimethyl ammonium chloride, lauryl dihydroxyethyl methyl ammonium chloride, oleyl bis polyoxyethylene methyl ammonium chloride, lauroyl aminopropyl dimethyl ethyl ammonium etosulphate, lauroyl aminopropyl dimethyl hydroxyethyl ammonium perchlorate, alkylbenzene dimethyl Ammonium chloride, alkyltri Quaternary ammonium salts such as chill chloride; and the like.

  Specific examples of the nonionic surfactant include alkyl ethers such as polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether, polyoxy Alkyl phenyl ethers such as ethylene nonyl phenyl ether; alkyl esters such as polyoxyethylene laurate, polyoxyethylene stearate, polyoxyethylene oleate; polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyoxyethylene Alkylamines such as oleyl amino ether, polyoxyethylene soybean amino ether, polyoxyethylene beef tallow amino ether; Alkyl amides such as ethylene lauric acid amide, polyoxyethylene stearic acid amide, polyoxyethylene oleic acid amide; vegetable oil ethers such as polyoxyethylene castor oil ether and polyoxyethylene rapeseed oil ether; lauric acid diethanolamide, stearic acid Alkanolamides such as diethanolamide and oleic acid diethanolamide; sorbitan ester ethers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate And so on.

  The content of the surfactant in each dispersion is not particularly limited as long as it does not inhibit the present invention, and is generally a small amount, specifically, a crystalline binder resin particle dispersion, and the like. In the case of this resin dispersion, it is about 0.01-1 mass%, More preferably, it is 0.02-0.5 mass%, More preferably, it is about 0.1-0.2 mass%. When the content is less than 0.01% by mass, aggregation may occur particularly when the pH of the resin particle dispersion is not sufficiently basic. In the case of a dispersion of other components such as a colorant particle dispersion and a release agent, the content is about 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, More preferably, it is about 0.5-2 mass%. If the content is less than 0.01% by mass, the stability between the particles differs during aggregation, which may cause problems such as the release of specific particles. If the content exceeds 10% by mass, the particle size of the particles This is not preferable because the distribution becomes wide and the control of the particle size may be difficult.

  In the method for producing an electrophotographic toner of the present invention, examples of the dispersion medium in each dispersion include an aqueous medium. Examples of the aqueous medium include water such as distilled water and ion exchange water, alcohol, and the like. These may be used individually by 1 type and may use 2 or more types together.

In the electrophotographic toner production method of the present invention, in the aggregation step, for the purpose of stabilizing the aggregated particles and controlling the particle size / particle size distribution, an ionic surfactant having a different polarity from the aggregated particles, a metal salt, etc. A compound having a monovalent or higher charge can also be added. In addition, a flocculant can be added as a method for stably and rapidly agglomerating particles or obtaining agglomerated particles having a narrower particle size distribution.
As the flocculant, a compound having a monovalent or higher charge is preferable, and specific examples of the compound having a monovalent or higher charge as the flocculant include water-soluble compounds such as the above-mentioned ionic surfactants and nonionic surfactants. Surfactants, acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, metal salts of inorganic acids such as magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, sodium carbonate , Aliphatic acid such as sodium acetate, potassium formate, sodium oxalate, sodium phthalate, potassium salicylate, metal salt of aromatic acid, metal salt of phenol such as sodium phenolate, metal salt of amino acid, triethanolamine hydrochloride And inorganic acid salts of aliphatic and aromatic amines such as salts and aniline hydrochloride. In consideration of the stability of the aggregated particles, the stability of the aggregating agent with respect to heat and time, and removal during washing, a metal salt of an inorganic acid is preferable in terms of performance and use.

  The amount of the flocculant added varies depending on the valence of the charge, but all of them are small amounts. The monovalent is about 3% by mass or less, the divalent is about 1% by mass or less, and the trivalent is 0 About 5% by mass or less. Since a smaller amount of the flocculant is preferable, a compound having a higher valence is preferable.

<Electrostatic image developer>
The electrostatic image developer of the present invention contains at least the electrophotographic toner of the present invention. The electrostatic image developer of the present invention is not particularly limited except that it contains the electrophotographic toner of the present invention, and can have an appropriate component composition depending on the purpose. When the electrophotographic toner of the present invention is used alone, it is prepared as a one-component electrostatic image developer, and when used in combination with a carrier, it is prepared as a two-component electrostatic image developer.

There is no restriction | limiting in particular as a carrier, A itself well-known carrier is mentioned, For example, a resin coating carrier can be used. As the resin-coated carrier, known carriers such as resin-coated carriers described in JP-A Nos. 62-39879 and 56-11461 can be used. For example, the following resin-coated carriers can be mentioned.
Examples of the core particle of the carrier include ordinary iron powder, ferrite, and magnetite granulated product, and the average diameter thereof is about 30 to 200 μm. Examples of the core particle coating resin include styrenes such as styrene, parachlorostyrene, and α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, Α-methylene fatty acid monocarboxylic acids such as methyl methacrylate, n-propyl methacrylate, lauryl methacrylate and 2-ethylhexyl methacrylate, nitrogen-containing acrylics such as dimethylaminoethyl methacrylate, vinyl nitriles such as acrylonitrile and methacrylonitrile Vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl kets such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isoprobenyl ketone. Tones, olefins such as ethylene and propylene, homopolymers such as vinyl-based fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene, or copolymers comprising two or more monomers, methyl silicone, Examples thereof include silicones such as methylphenyl silicone, polyesters containing bisphenol and glycol, epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like.

  These resins may be used alone or in combination of two or more. The amount of the coating resin is about 0.1 to 10 parts, preferably 0.5 to 3.0 parts, with respect to the core particles. Moreover, a heating type kneader, a heating type Henschel mixer, a UM mixer, etc. can be used for manufacture of a carrier, A heating type fluidized rolling bed, a heating type kiln, etc. are used depending on the quantity of the said coating resin. Can do.

  As the carrier, a magnetic powder dispersion type carrier in which magnetic fine particles are dispersed in a resin can be used for low potential and high development. The magnetic fine particles in the magnetic powder-dispersed carrier include usually used ferromagnetic materials, specifically, magnetic metals such as iron, cobalt and nickel, alloys thereof, and metal oxides such as cobalt-added iron oxide and chromium oxide. Various ferrites such as Mn · Zn ferrite and Ni · Zn ferrite, magnetite, hematite and the like can be used. These magnetic fine powders preferably have a particle size in the range of 0.05 to 1.0 μm. The content of the magnetic fine particles is usually about 30 to 95% by weight with respect to the total weight of the carrier component. In addition, a resin, a charge control agent, a coupling agent, a filler, and other fine powders can be added to the carrier for charge control, dispersion improvement, strength reinforcement, fluidity improvement, and other purposes. The magnetic powder-dispersed carrier is a carrier particle obtained by kneading, pulverizing, or classifying a resin and magnetic powder as exemplified above, and a charge control agent as necessary, or the above components are liquefied by solvent or heating, spray drying, etc. Can be used.

  The mixing ratio (weight ratio) of the electrophotographic toner of the present invention and the carrier in the two-component developer is in the range of toner: carrier = 1: 100 to 30: 100, and 3: 100 to 20: A range of about 100 is more preferable.

<Image forming method>
Next, an image forming method using the electrostatic charge image developer of the present invention will be described. The image forming method uses a latent image forming step of forming an electrostatic latent image on the surface of the latent image carrier and an electrostatic charge image developer carried on the developer carrier, and is formed on the surface of the latent image carrier. A developing process for developing the electrostatic latent image to form a toner image, a transfer process for transferring the toner image formed on the surface of the latent image carrier to the surface of the transfer material such as paper, and the surface of the transfer target And a fixing step of thermally fixing the transferred toner image, wherein the electrostatic image developer of the present invention is used as the electrostatic image developer. As the latent image carrier, for example, an electrophotographic photosensitive member and a dielectric recording member can be used.

In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic latent image.
Next, the electrostatic latent image formed on the latent image carrier is developed with the electrostatic image developer of the present invention to form a toner image (development process). In electrophotography, a developer layer is formed on the surface of a developer carrier disposed opposite to the latent image carrier, and the electrostatic latent image formed on the surface of the latent image carrier is developed by the developer layer. To do. In the case of a two-component development method comprising a toner and a carrier, the developer layer is formed by a so-called magnetic brush in which a magnetic carrier is formed on the surface of the developer carrying member in the form of a brush, and the toner adheres to this.

Using a corotron charger or the like, the toner image formed on the latent image carrier is transferred onto the surface of a transfer medium such as paper. In this case, in addition to transferring the toner image obtained in the development process as it is to the transfer medium, it is possible to use an intermediate transfer body and once transfer to the intermediate transfer body and then transfer to the transfer material. .
When a full color image is to be obtained, a toner image developed using toner of at least three colors of cyan, magenta and yellow and, if necessary, four colors of black in the development process is laminated and transferred. Is done. At this time, it is preferable to use an intermediate transfer member to once transfer the layers onto the intermediate transfer member, and then transfer them all at once to a transfer target member in order to obtain an image having no misalignment and good color development. Is.
When a single color image is to be obtained, the toner weight (TMA) in the 100% area area of the transfer image transferred onto the transfer medium in the transfer step is preferably 0.80 mg / cm ² or less. 60 mg / cm ² or less is more preferable.

  Further, the toner image transferred to the surface of the transfer target is heat-fixed by a heating type fixing device, and a final toner image is formed. Examples of the heating type fixing device include a contact heating type fixing method using a heating roll or the like, and a non-contact heating type fixing method using oven heating. However, a contact type fixing device should be used from the viewpoint of reliability, safety, and thermal efficiency. Is preferred. The contact-type fixing device referred to here is a fixing device of a type in which a fixing member such as a fixing roll presses the transferred material on which the transferred image is formed to fix the transferred image on the transferred material. A known contact-type fixing device can be widely used. As a method of pressure contact, a transfer object on which a transfer image is formed is passed between two contacting rolls or between a contacting roll and a belt, and transferred in a roll-roll or roll-belt nip region. For example, a method of pressing and fixing an image may be used.

Examples of the transfer target (recording material) to which the toner image is transferred include plain paper and OHP sheet used for electrophotographic copying machines, printers, and the like.
In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer object is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing Etc. can be used suitably.
By using the electrophotographic toner of the present invention, fixing at a significantly lower temperature is possible than before, energy consumption in the fixing process and warm-up time can be greatly reduced, and the formed image is excellent. Preservability can also be realized. Further, since the toner has excellent fluidity and transferability, an image with excellent image quality can be formed, and charging can be stabilized. Furthermore, since the transfer efficiency is improved, the residual toner is reduced and the cost can be reduced.

  In the image forming method of the present invention, each of the 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.

Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “part” means a part.
Each measurement in the examples was performed as follows.

  The melting point and glass transition temperature of the resin in the core particles and the toner particles were measured using a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50) under a temperature rising rate of 3 ° C./min.

The shape factors of the core particles and toner particles were measured by the following method.
The particles were spread on a glass slide of several mg, and a drop of silicone oil was added to blend well with the particles, and a preparation was placed thereon. Subsequently, the glass slide was magnified by a Nikon Microphoto FXA made by Nikon Corporation at a magnification of 250 times, and the particle image was taken into an image analyzer (Luzex FT) made by Nireco Corporation to obtain a binarized image. It was. Image analysis was performed by randomly sampling 200 particles on the image, and an average value of the shape factor SF1 was obtained using the following equation (5).

SF1 = (R ² × π) / (A × 4) × 100 (5)
(In the above formula (5), R represents the maximum length of the particle, and A represents the projected area of the particle.)

The arithmetic average height distribution and arithmetic average height fluctuation of the toner were determined by the following methods.
The arithmetic average height of the toner was measured with an ultra-deep color 3D shape measuring microscope VK-9500 manufactured by Keyence Corporation. In this apparatus, a sample is irradiated with a laser to perform three-dimensional scanning. The laser reflected light at each position is monitored with a CCD camera to obtain three-dimensional surface information of the sample. The obtained surface information is statistically processed to obtain an index related to the surface roughness. In the measurement this time, the surface of one toner is 3 × 2 μm square in a vertical and horizontal direction (in the XY axis plane) under a scanning condition with a laser scanning pitch of 0.01 μm in the height direction (Z-axis direction) with a field of view of a lens magnification of 3000 times. The dimension is measured, and the arithmetic average height of one toner is obtained. Further, at the time of measurement, γ = 0.3 was set as γ correction, and as a noise cut analysis, a height smoothing process was performed once to obtain the surface roughness. This operation was repeated for 1000 toners, and the data was statistically processed to obtain the arithmetic average height distribution of the toner. Moreover, the standard deviation (percentage) with respect to the average value of arithmetic average height was calculated | required, and it was set as the fluctuation | variation of arithmetic average height.

  Whether or not a plurality of core particles are contained in the toner particles can be confirmed by TEM observation of the cross section of the toner particles. In particular, since crystalline materials tend to be unevenly distributed among the crystalline materials, confirmation is easier.

  The proportion of toner particles containing a plurality of core particles in all toner particles is such that the particle size of the toner cross section of the TEM image is 90% to 120% of the volume average particle size measured in advance by a Coulter counter. 100 corresponding cross-sectional photographs were selectively measured, and the ratio of toner particles containing a plurality of core particles was calculated.

(Toner particle, core particle size, particle size distribution measurement method)
The toner particle size and particle size distribution index were measured using a Coulter Counter TAII (manufactured by Beckman-Coulter) and the electrolyte using ISOTON-II (manufactured by Beckman-Coulter). As a measurement method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of sodium alkylbenzenesulfonate, which is a surfactant, as a dispersant. This is added to 100 to 150 ml of the electrolytic solution.
The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles of 0.6 to 18 μm is measured using the Coulter counter TAII type with an aperture diameter of 50 μm. Volume average distribution and number average distribution were determined. For the particle size range (channel) obtained by dividing the measured particle size distribution, a cumulative distribution is drawn from the large particle side for each volume and number, and the particle diameters that become 16% cumulative are defined as D16v and D16p. % Particle size was defined as D50v and D50p. Using these, the particle size distribution (formula (1)) of the toner particles was obtained.

(Measurement method of molecular weight and molecular weight distribution of resin)
In the toner of the present invention, the molecular weight distribution of the resin is performed under the following conditions. GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)”, and the column uses two “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)” THF (tetrahydrofuran) was used as an eluent. As experimental conditions, the sample concentration was 0.5%, and the flow rate was 0.6 ml / min. The experiment was conducted using a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.
Measurement of the amount of buried inorganic fine particles, loosening / hardening bulk density, average circularity, and variation in circularity were performed by the methods described above.

-Preparation of crystalline polyester resin (1)-
In a heat-dried three-necked flask, 124 parts of ethylene glycol, 22.2 parts of sodium dimethyl 5-sulfoisophthalate, 213 parts of dimethyl sebacate, and 0.3 part of dibutyltin oxide as a catalyst were added, and then the container was subjected to a decompression operation. The inside air was brought into an inert atmosphere with nitrogen gas, and stirred at 180 ° C. for 5 hours by mechanical stirring. Thereafter, the temperature was gradually raised to 220 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled, the reaction was stopped, and 220 parts of crystalline polyester resin (1) was synthesized.
The obtained crystalline polyester resin (1) had a weight average molecular weight (MW) of 9,700 and a number average molecular weight (Mn) of 5,400.
Further, the melting point (Tm) of the crystalline polyester resin (1) was measured by the above-described measuring method using a differential scanning calorimeter (DSC). As a result, the crystalline polyester resin (1) had a clear peak and the peak top temperature (melting point). Was 69 ° C.
The content ratio of the copolymerization component (5-sulfoisophthalic acid component) and the sebacic acid component measured and calculated from the NMR spectrum of the resin was 7.5: 92.5.

-Preparation of resin particle dispersion (1)-
150 parts of the crystalline polyester resin (1) is put in 850 parts of distilled water, mixed and stirred with a homogenizer (IKA Japan Co., Ltd .: Ultra Tarax) while heating to 85 ° C., and the resin particle dispersion (1) is obtained. Obtained.

-Preparation of colorant dispersion (1)-
After mixing and dissolving 250 parts of a cyan pigment (manufactured by Dainichi Seika Co., Ltd .: ECB-301), 20 parts of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) and 730 parts of ion-exchanged water, a homogenizer ( A colorant dispersion (1) prepared by dispersing the colorant (cyan pigment) was prepared using IKA: Ultra Tarax.

-Preparation of colorant dispersion (2)-
250 parts of magenta pigment (manufactured by Dainichi Seika Co., Ltd .: ECR-186Y), 20 parts of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK), and 730 parts of ion-exchanged water are mixed to obtain a colorant dispersion (1). A colorant dispersion liquid (2) obtained by dissolving and dispersing in the same manner as above to disperse the colorant (magenta pigment) was prepared.

-Preparation of colorant dispersion (3)-
250 parts of yellow pigment (Clariant Japan Co., Ltd .: Hansa Brill. Yellow 5GX03), 20 parts of anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) and 730 parts of ion-exchanged water are mixed, and a colorant dispersion (1 ) Was dissolved and dispersed by the same method as above to prepare a colorant dispersion (3) in which a colorant (yellow pigment) was dispersed.

-Preparation of colorant dispersion (4)-
Mixing 250 parts of carbon black (manufactured by Cabot: Regal 330), 20 parts of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK), and 730 parts of ion-exchanged water, the same as the colorant dispersion (1) A colorant dispersion (4) obtained by dissolving and dispersing by the method and dispersing the colorant (carbon black) was prepared.

-Preparation of release agent dispersion A-
350 parts of a release agent (Riken Vitamin Co., Ltd .: Riquemar B-200, melting point: 68 ° C.), 15 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) and 635 parts of ion-exchanged water are mixed. -Dispersed using a homogenizer (manufactured by IKA: Ultra Tarax) while being heated to 90 ° C on a bath to prepare a release agent dispersion A.

-Preparation of core particles (1)-
1600 parts of resin particle dispersion (1), 52 parts of colorant dispersion (1), 66 parts of release agent dispersion A, 5 parts of calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.), 100 parts of ion-exchanged water, round stainless steel After being accommodated in a flask and adjusted to pH 4.5, the mixture was dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then heated to 65 ° C. with stirring in an oil bath for heating. After maintaining at 65 ° C. for 2 hours, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of 3.0 μm were formed. Furthermore, after maintaining heating and stirring at 65 ° C. for 0.5 hours, it was confirmed that aggregated particles having a volume average particle diameter of 3.5 μm were formed by observation with an optical microscope.
The pH of this aggregated particle dispersion was 4.0. Therefore, an aqueous solution obtained by diluting sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) to 0.5% by mass was gently added to adjust the pH to 5.0. The aggregated particle dispersion was heated to 78 ° C. while being stirred and held for 30 minutes, and then observed with an optical microscope, and coalesced spherical particles were observed. Thereafter, the temperature was lowered to 30 ° C. at a rate of 10 ° C./min while adding ion-exchanged water to solidify the particles.
Thereafter, the reaction product was filtered, sufficiently washed with ion-exchanged water, filtered and dried to obtain core particles (1).
The volume average particle diameter of the obtained core particles (1) was 3.5 μm. Further, the shape factor SF1 of the core particle (1) was 118.

-Preparation of core particles (2)-
1600 parts of resin particle dispersion (1), 52 parts of colorant dispersion (1), 66 parts of release agent dispersion A, 5 parts of calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.), 100 parts of ion-exchanged water, round stainless steel After being accommodated in a flask and adjusted to pH 4.5, the mixture was dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then heated to 65 ° C. with stirring in an oil bath for heating. After maintaining at 65 ° C. for 2 hours, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of 3.0 μm were formed. Furthermore, after maintaining heating and stirring at 65 ° C. for 0.5 hours, it was confirmed that aggregated particles having a volume average particle diameter of 3.5 μm were formed by observation with an optical microscope.
The pH of this aggregated particle dispersion was 4.0. Therefore, an aqueous solution obtained by diluting sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) to 0.5% by mass was gently added to adjust the pH to 5.0. The agglomerated particle dispersion was heated to 78 ° C. and kept for 5 minutes while continuing stirring, and then observed with an optical microscope, and coalesced particles were observed. Thereafter, the temperature was lowered to 30 ° C. at a rate of 10 ° C./min while adding ion-exchanged water to solidify the particles.
Thereafter, the reaction product was filtered, sufficiently washed with ion-exchanged water, filtered and dried to obtain core particles (2).
The volume average particle diameter of the obtained core particles (2) was 3.5 μm. Further, the shape factor SF1 of the core particle (2) was 126.

-Preparation of core particles (3)-
1600 parts of resin particle dispersion (1), 52 parts of colorant dispersion (1), 66 parts of release agent dispersion A, 5 parts of calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.), 100 parts of ion-exchanged water, round stainless steel The mixture was placed in a flask and adjusted to pH 4.0, and then dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then heated to 65 ° C. with stirring in an oil bath for heating. After maintaining at 65 ° C. for 3 hours and observing with an optical microscope, it was confirmed that aggregated particles having a volume average particle diameter of 5.0 μm were formed.
Furthermore, after maintaining heating and stirring at 65 ° C. for 1 hour, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of 5.5 μm were formed. The pH of this aggregated particle dispersion was 3.8. Therefore, an aqueous solution obtained by diluting sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) to 0.5% by mass was gently added to adjust the pH to 5.0. The aggregated particle dispersion was heated to 78 ° C. while being stirred and held for 15 minutes, and then observed with an optical microscope, and coalesced spherical particles were observed. Thereafter, the temperature was lowered to 30 ° C. at a rate of 10 ° C./min while adding ion-exchanged water to solidify the particles.
Thereafter, the reaction product was filtered, sufficiently washed with ion exchange water, and then filtered and dried to obtain core particles (3).
The obtained core particles (3) had a volume average particle diameter of 5.5 μm. The shape factor SF1 of the core particle (3) was 120.

-Preparation of core particles (4)-
Core particles (4) were obtained in the same manner as the core particles (1) except that 52 parts of the colorant dispersion (1) was changed to 90 parts of the colorant dispersion (2).
The obtained core particles (4) had a volume average particle size of 3.4 μm. Further, the shape factor SF1 of the core particle (4) was 118.

-Preparation of core particles (5)-
Core particles (5) were obtained in the same manner as the core particles (1) except that 52 parts of the colorant dispersion (1) was changed to 125 parts of the colorant dispersion (3).
The volume average particle diameter of the obtained core particles (5) was 3.5 μm. Further, the shape factor SF1 of the core particle (5) was 119.

-Preparation of core particles (6)-
Core particles (6) were obtained in the same manner as the core particles (1) except that the colorant dispersion (1) was changed to the colorant dispersion (4).
The volume average particle diameter of the obtained core particles (6) was 3.5 μm. Further, the shape factor SF1 of the core particle (6) was 118.

-Preparation of core particles (7)-
1600 parts of resin particle dispersion (1), 52 parts of colorant dispersion (1), 66 parts of release agent dispersion A, 5 parts of calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.), 100 parts of ion-exchanged water, round stainless steel The mixture was placed in a flask and adjusted to pH 4.0, and then dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then heated to 65 ° C. with stirring in an oil bath for heating. After maintaining at 65 ° C. for 3 hours, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of 5.2 μm were formed.
After maintaining heating and stirring at 65 ° C. for another hour, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of 5.7 μm were formed. The pH of this aggregated particle dispersion was 3.8. Therefore, an aqueous solution obtained by diluting sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) to 0.5% by mass was gently added to adjust the pH to 5.0. The aggregated particle dispersion was heated to 78 ° C. while being continuously stirred and held for 60 minutes, and then observed with an optical microscope, and coalesced spherical particles were observed. Thereafter, the temperature was lowered to 30 ° C. at a rate of 15 ° C./min while adding ion-exchanged water to solidify the particles.
Thereafter, the reaction product was filtered, sufficiently washed with ion-exchanged water, filtered and dried to obtain core particles (7).
The obtained core particles (7) had a volume average particle diameter of 5.8 μm. In addition, the shape factor SF1 of the core particles (7) was 115.

-Preparation of coated fine particle dispersion A-
Oil layer Styrene (Wako Pure Chemical Industries) 30 parts n-Butyl Acrylate (Wako Pure Chemical Industries) 10 parts β Carboethyl Acrylate (Rhodia Nikka) 1.5 parts Dodecanethiol (Wako Pure Chemical Industries) 0.5 parts Tier 1
Ion-exchanged water 18.0 parts Anionic surfactant (manufactured by Rhodia) 1.0 part ・ Aqueous layer 2
Deionized water 40 parts Anionic surfactant (manufactured by Rhodia) 0.1 part Ammonium persulfate (manufactured by Wako Pure Chemical Industries) 0.4 part

The above oil layer component and water layer 1 component were placed in a flask and mixed with stirring to obtain a monomer emulsified dispersion. The components of the aqueous layer 2 were put into a reaction vessel, and the inside of the vessel was sufficiently substituted with nitrogen and stirred, and then heated in an oil bath until the temperature in the reaction system reached 75 ° C. The monomer emulsion dispersion was gradually dropped into the reaction vessel over 3 hours to carry out emulsion polymerization. After completion of the dropwise addition, the polymerization was further continued at 75 ° C., and the polymerization was terminated after 3 hours.
The obtained resin fine particles were 150 nm when the number average particle diameter D50n of the resin fine particles was measured with a Doppler scattering type particle size distribution analyzer (manufactured by Nikkiso Co., Ltd., Microtrac UPA 9340), and a differential scanning calorimeter (manufactured by Shimadzu Corporation) DSC-50) was used to measure the glass transition point of the resin at a temperature elevation rate of 10 ° C./min. As a result, it was 53 ° C. and the number average molecular weight was 13,000.

-Preparation of toner particles (1)-
150 parts of core particles (1), 60 parts of the coated fine particle dispersion A, and 300 parts of ion-exchanged water were stirred for 30 minutes while maintaining the temperature at 30 ° C. in a heating oil bath. The pH of the slurry was adjusted to 2.5 using nitric acid, 0.3 part of a 10% aqueous solution of polyaluminum chloride was added and stirred for 10 minutes, and then heated to 45 ° C at a rate of 0.1 ° C / min. The temperature rose. During the temperature increase, when the temperature reached 45 ° C., the pH was adjusted to 2.5, 5 parts of the coated particle dispersion A was further added, and then the temperature was increased to 57 ° C. at a temperature increase rate of 0.1 ° C./min. When the temperature reached 50 ° C., 2 parts of an anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added, and the pH was raised to 8.0 using an aqueous sodium hydroxide solution. . After the temperature reached 57 ° C., the temperature was maintained for 6 hours with stirring. Thereafter, the temperature is lowered to 30 ° C. at a rate of −1 ° C./min, passed through a 20 μm sieve, filtered, sufficiently washed with ion-exchanged water, dried in a vacuum dryer, and moisture content 0.4 A mass% of toner (1) was obtained. It should be noted that stirring during the preparation of the toner was operated at a stirring blade tip peripheral speed of 1.8 m / s as needed.
The obtained toner particles (1) had a volume average particle diameter of 6.1 μm. Further, the shape factor SF1 of the toner particles (1) was 130.
The ratio of toner particles containing a plurality of core particles to all toner particles was 63%.

-Preparation of toner particles (2)-
Toner particles (2) were obtained in the same manner as toner particles (1) except that the core particles (1) were changed to core particles (2).
The obtained toner particles (2) had a volume average particle diameter of 6.0 μm. The shape factor SF1 of the toner particles (2) was 131.
The ratio of toner particles containing a plurality of core particles to all toner particles was 61%.

-Preparation of toner particles (3)-
Toner particles (3) were obtained in the same manner as toner particles (1) except that the core particles (1) were changed to core particles (4).
The obtained toner particles (3) had a volume average particle diameter of 5.8 μm. The shape factor SF1 of the toner particles (3) was 128.
The ratio of toner particles containing a plurality of core particles to all toner particles was 61%.

-Preparation of toner particles (4)-
Toner particles (4) were obtained in the same manner as toner particles (1) except that the core particles (1) were changed to core particles (5).
The obtained toner particles (4) had a volume average particle diameter of 6.2 μm. The toner particle (4) had a shape factor SF1 of 128.
The ratio of toner particles containing a plurality of core particles to all toner particles was 62%.

-Preparation of toner particles (5)-
Toner particles (5) were obtained in the same manner as toner particles (1) except that the core particles (1) were changed to core particles (6).
The obtained toner particles (5) had a volume average particle diameter of 6.3 μm. The shape factor SF1 of the toner particles (5) was 130.
The ratio of toner particles containing a plurality of core particles to all toner particles was 60%.

-Preparation of toner particles (6)-
Toner particles (6) were obtained in the same manner as toner particles (1) except that the core particles (1) were changed to core particles (3).
The obtained toner particles (6) had a volume average particle diameter of 8.2 μm. The shape factor SF1 of the toner particles (6) was 130.
The ratio of toner particles containing a plurality of core particles to all toner particles was 24%.

-Preparation of toner particles (7)-
When the temperature reached 40 ° C. during the temperature increase, 2 parts of an anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added, and the pH was raised to 8.0 using an aqueous sodium hydroxide solution. Toner particles (7) were obtained in the same manner as toner particles (6).
The obtained toner particles (7) had a volume average particle diameter of 6.5 μm. The shape factor SF1 of the toner particles (7) was 127.
The ratio of toner particles containing a plurality of core particles to all toner particles was 22%.

-Production of toner particles (8)-
Toner particles (8) were obtained in the same manner as toner particles (1) except that the coating resin particle dispersion A was changed from 60 parts to 23 parts.
The obtained toner particles (8) had a volume average particle diameter of 6.0 μm. The shape factor SF1 of the toner particles (8) was 130.
The ratio of toner particles containing a plurality of core particles to all toner particles was 45%.

-Preparation of toner particles (9)-
Toner particles (9) were obtained in the same manner as toner particles (1) except that the coating resin particle dispersion A was changed from 60 parts to 71 parts.
The obtained toner particles (9) had a volume average particle diameter of 6.2 μm. Further, the shape factor SF1 of the toner particles (9) was 130.
The ratio of the toner particles containing a plurality of core particles to the total toner particles was 54%.

-Production of toner particles (10)-
Toner particles (10) were obtained in the same manner as toner particles (1) except that the coating resin particle dispersion A was changed from 60 parts to 15 parts.
The obtained toner particles (10) had a volume average particle diameter of 5.8 μm. Further, the shape factor SF1 of the toner particles (10) was 130.
The ratio of toner particles containing a plurality of core particles to all toner particles was 33%.

-Preparation of toner particles (11)-
Toner particles (11) were obtained in the same manner as toner particles (1) except that the coating resin particle dispersion A was changed from 60 parts to 94 parts.
The obtained toner particles (11) had a volume average particle diameter of 6.5 μm. Further, the shape factor SF1 of the toner particles (11) was 130.
The ratio of toner particles containing a plurality of core particles to all toner particles was 49%.

-Production of toner particles (12)-
150 parts of the core particles (2), 60 parts of the coated fine particle dispersion A, and 150 parts of ion exchange water were stirred for 30 minutes while maintaining the temperature at 30 ° C. in a heating oil bath. The pH of the slurry was adjusted to 2.5 using nitric acid, 0.3 part of a 10% aqueous solution of polyaluminum chloride was added and stirred for another 10 minutes, and then heated to 40 ° C. at a rate of 0.1 ° C./min. The temperature rose. When the temperature reached 40 ° C. during the temperature increase, 5 parts of the coated particle dispersion A was further added, and then the temperature was increased to 57 ° C. at a temperature increase rate of 0.1 ° C./min. When the temperature reached 48 ° C., 2 parts of an anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added, and the pH was raised to 8.0 using an aqueous sodium hydroxide solution, and the temperature was continued as it was. . After the temperature reached 57 ° C., the temperature was maintained for 6 hours with stirring. Thereafter, the temperature is lowered to 30 ° C. at a rate of −1 ° C./min, passed through a 20 μm sieve, filtered, sufficiently washed with ion-exchanged water, dried in a vacuum dryer, and moisture content 0.4 A mass% of toner (12) was obtained. It should be noted that stirring during toner preparation was performed at any time with the tip peripheral speed of the stirring blade being 10.0 m / s.
The obtained toner particles (12) had a volume average particle diameter of 3.7 μm. Further, the shape factor SF1 of the toner particles (12) was 124.
The ratio of the toner particles containing a plurality of core particles to the total toner particles was 5%.

-Preparation of toner particles (13)-
Toner particles (13) were obtained in the same manner as toner particles (12) except that the core particles (2) were changed to core particles (3).
The obtained toner particles (13) had a volume average particle diameter of 5.7 μm. The shape factor SF1 of the toner particles (13) was 120.
The ratio of toner particles containing a plurality of core particles to all toner particles was 17%.

-Production of toner particles (14)-
Toner particles (14) were obtained in the same manner as toner particles (12) except that the core particles (2) were changed to core particles (7).
The obtained toner particles (14) had a volume average particle diameter of 6.1 μm. The shape factor SF1 of the toner particles (14) was 117.
The ratio of the toner particles containing a plurality of core particles to the total toner particles was 12%.

  Silica fine particles having an average primary particle diameter (volume average particle diameter) of 40 nm (hydrophobic silica manufactured by Nippon Aerosil Co., Ltd .: RX50) 1 obtained by surface-hydrophobizing the toner particles (1) to (14) and the core particles 7 0.5% by mass and a metatitanic acid compound having an average primary particle size (volume average particle size) of 20 nm, which is a reaction product obtained by treating 100 parts of metatitanic acid with 40 parts of isobutyltrimethoxysilane and 10 parts of trifluoropropyltrimethoxysilane 0.9% by mass of fine particles were added and mixed with a Henschel mixer at a peripheral speed of 30 m / s for 10 minutes. Thereafter, it is sieved with a 45 μm sieving mesh, and electrophotographic toners (1) to (14): (to which toner particles 1 to 14 are externally added), and electrophotographic toner (15): (core particles 7 are Externally added) was prepared.

-Preparation of toner particles (16)-
100 parts of the particles before being dried by the vacuum dryer used in the production of the toner particles (1) were dried in a heated air stream using a hot air dryer flash jet dryer FJD-2 (manufactured by Seishin Enterprise). The toner was again passed through a flash jet dryer FJD-2 to obtain toner particles (dry toner) (16) having a moisture content of 0.2% by mass.
The ratio of toner particles containing a plurality of core particles to all toner particles was 63%.
Toner particles (16) were subjected to surface hydrophobization treatment, silica primary particles having an average primary particle size (volume average particle size) of 40 nm (hydrophobic silica manufactured by Nippon Aerosil Co., Ltd .: RX50) 1.5% by mass, and 100 parts of metatitanic acid. The reaction product treated with 40 parts of isobutyltrimethoxysilane and 10 parts of trifluoropropyltrimethoxysilane was mixed with 0.9% by mass of metatitanic acid compound fine particles having an average primary particle size (volume average particle size) of 20 nm. The mixture was added and mixed with a mixer at a peripheral speed of 30 m / s for 10 minutes. Thereafter, it was sieved with a 45 μm sieving mesh to produce an electrophotographic toner (16).

-Carrier manufacturing-
Carbon black (trade name; VXC-72, manufactured by Cabot) 0.14 part was mixed with 1.3 parts of toluene, and a trifunctional isocyanate 80% by mass ethyl acetate solution ( Takenate D110N: Takeda Pharmaceutical Co., Ltd.) 1.23 parts of the coating agent resin solution mixed and stirred and mn-mg-Sr ferrite particles (average particle size: 35 μm) were put into a kneader and mixed and stirred at room temperature for 10 minutes. Thereafter, the temperature was raised to 150 ° C. at normal pressure to distill off the solvent. Further, after mixing and stirring for 60 minutes, the heater was turned off and the temperature was lowered to 50 ° C. The obtained coated carrier was sieved with a 75 μm mesh to prepare Carrier A.

-Preparation of electrostatic image developer-
5 parts of electrophotographic toners (1) to (16) and 95 parts of carrier A are placed in a V blender and stirred for 20 minutes, and then sieved with a 105 μm mesh to produce electrostatic charge image developers (1) to (16). did.

<Example 1>
-Evaluation of transferability-
The obtained electrostatic charge image developer (1) was put into DocuColor 1250 (manufactured by Fuji Xerox Co., Ltd.), and an unfixed image was collected under the following conditions under an environment of 25 ° C./50% RH. The transfer efficiency was measured. Further, 10,000 copies were made under an environment of 25 ° C./50% RH, and the transfer efficiency was measured in the same manner. The transfer efficiency was calculated by the following formula (6) using a solid image. The results are shown in Table 1.

Transfer efficiency (%) = toner amount on paper / (toner amount on paper + transfer residual toner amount on photoconductor) (6)

[Image formation conditions]
(A) Toner image: Solid image (40 mm 50 mm) Toner amount (on recording paper): 0.40 mg / cm ² Recording paper: Color copy paper (J paper) manufactured by Fuji Xerox Co., Ltd.

-Image quality evaluation-
The fixed image quality of the solid image after printing 10,000 sheets was visually evaluated according to the following evaluation criteria. The results are shown in Table 1.
[Image Evaluation Criteria]
(Transcription)
◯: No transfer unevenness and no problem Δ: Some transfer unevenness was observed but no practical problem ×: Large transfer unevenness was observed and practically unusable (cleaning)
○: No color point or black streak Δ: Some color point or black streak is observed ×: Color point or black streak is observed and is not practically usable.

-Evaluation of low-temperature fixability-
A fixing device of DocuPrint C2220 (manufactured by Fuji Xerox Co., Ltd.) was modified so that the fixing temperature was variable, and the low-temperature fixing property of the electrophotographic toner (1) was evaluated using the unfixed image. After producing a fixed image at the set fixing machine temperature, the image surface of each obtained fixed image is valley-folded, the degree of peeling of the image at the crease part is observed, and the lowest fixing temperature at which the image hardly peels off Was measured as MFT (° C.) to evaluate low-temperature fixability. The results are shown in Table 1.

-Evaluation of charge retention-
After printing 10 sheets (initial), the copying machine was once stopped, and the developer was collected from the mag sleeve. The collected developer was left in a 25 ° C./50% RH environment for 10 minutes and 24 hours after stopping the copying machine, and the amount of charge was measured. Similarly, the charge amount of the developer after printing 10,000 sheets was measured by the same method.
From the difference between the charge amount of the developer left for 10 minutes after printing 10 sheets and the charge amount of the developer left for 24 hours after printing 10000 sheets, the charge retention was evaluated according to the following criteria.
[Electricity maintenance criteria]
A: Charge amount difference is 0 μC / mg or more and less than 5 μC / mg.
A: Charge amount difference of 5 μC / mg or more and less than 10 μC / mg.
Δ: Charge amount difference 10 μC / mg or more and less than 15 μC / mg.
X: Charge amount difference 15 μC / mg or more.

Example 2 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (2). The results are shown in Table 1.

Example 3 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (3). The results are shown in Table 1.

Example 4 Evaluation was carried out in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (4). The results are shown in Table 1.

Example 5 Evaluation was carried out in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (5). The results are shown in Table 1.

Example 6 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (6). The results are shown in Table 1.

Example 7 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (7). The results are shown in Table 1.

Example 8 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (8). The results are shown in Table 1.

Example 9 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (9). The results are shown in Table 1.

Example 10 Evaluation was carried out in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (10). The results are shown in Table 1.

Example 11 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (11). The results are shown in Table 1.

Example 12 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (16). The results are shown in Table 1.

Comparative Example 1 Evaluation was performed in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (12). The results are shown in Table 2.

Comparative Example 2 Evaluation was carried out in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (13). The results are shown in Table 2.

Comparative Example 3 Evaluation was carried out in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (14). The results are shown in Table 2.

Comparative Example 4 Evaluation was carried out in the same manner as in Example 1 except that the electrophotographic toner (1) was replaced with the electrophotographic toner (15). The results are shown in Table 2.

  As shown in Tables 1 and 2, according to the present invention, it is possible to obtain an electrophotographic toner that has excellent low-temperature fixability, excellent transferability even after printing 10,000 sheets, little image quality degradation, and high charge retention. Was confirmed. In addition, it was confirmed that a toner having higher charge maintaining property can be obtained by carrying out hot air drying after mixing the inorganic fine particles.

2 is a schematic cross-sectional view of a toner of the present invention. FIG. FIG. 6 is a schematic cross-sectional view showing another example of the toner of the present invention. FIG. 6 is a schematic cross-sectional view showing another example of the toner of the present invention. It is a figure which shows an example of the drying equipment used suitably for this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core particle 2 Coating agent 11 Dryer 12 Valve 13 Supply port 14 Chamber 15 Nozzle 16 Heat exchanger 17 Filter 18 Dust collector 19 Damper 20 Blower 21 Dryer exit

Claims (3)

An electrophotographic toner comprising toner particles in which core particles containing at least a crystalline binder resin are coated with a coating containing an amorphous polymer, and an external additive,
An electrophotographic toner in which a ratio of the toner particles including a plurality of the core particles is 20% or more. The ratio of the toner particles containing at least a core particle containing at least a crystalline binder resin with a coating agent containing an amorphous polymer and an external additive, and containing a plurality of the core particles is 20% or more. A method for producing a toner for electrophotography,
A coating agent attaching step of adhering the coating agent to the surface of the core particles by mixing the coating particle dispersion containing the coating agent and the core particles in an aqueous medium;
An aggregating step of aggregating the core particles to which the coating agent is adhered to form aggregated particles;
A fusing step of heating and fusing the aggregated particles to form toner particles;
A method for producing an electrophotographic toner having at least   The ratio of the toner particles containing at least a core particle containing at least a crystalline binder resin with a coating agent containing an amorphous polymer and an external additive, and containing a plurality of the core particles is 20% or more. An electrostatic image developer containing at least an electrophotographic toner.

Images