JP4830630B2 - Toner for developing electrostatic image, developer for developing electrostatic image, and image forming method - Google Patents

Description

  The present invention relates to an electrostatic image developing toner used in electrophotography and a method for producing the same. The present invention also relates to an electrostatic charge image developer using the electrostatic charge image developing toner and an image forming method.

Also in addition polymerization and polycondensation, the premise of random monomer chain is mainly to promote fixing by heating rather than pressure, so the energy reduction in electrophotographic method is greatly changed and improved. However, there is no means for realizing high-speed fixing with a simple fixing machine, which is important when dealing with the printing market using an electrophotographic method, especially when using cardboard.
Improves gloss unevenness, which tends to occur during high-speed fixing of thick paper, and achieves high-quality images with a high-speed and simple fixing machine. For this reason, in conventional polymerization, it has been difficult to precisely design a resin structure that can promote plasticization by pressure.

  On the other hand, with respect to polymers that are hard (high glass transition point (Tg)) and soft (low Tg) polymers at room temperature, certain combinations exhibit fluidity below the melting point of those polymers under pressure and form. Is possible. A polymer material having such properties is called baroplastic. For example, Patent Document 1 describes a ballo plastic, and pressure molded bodies, elastomers, and pressure sensitive adhesives are listed as application areas.

US Pat. No. 6,632,883

  The problem to be solved by the present invention is to provide an electrostatic image developing toner capable of reducing fixing energy even on cardboard while achieving both high image quality and reliability, a method for producing the same, and the electrostatic image developing toner. The electrostatic image developer used, and an image forming method are provided.

The above problems to be solved by the present invention have been solved by the following <1> to <4>.
<1> An electrostatic charge image developing toner obtained by aggregating resin particles having a core-shell structure, wherein both the core and the shell are non-crystalline resins, and the glass transition of the resin constituting the core The electrostatic charge image, wherein the point and the glass transition point of the resin constituting the shell differ by 20 ° C. or more, and the resin constituting the shell contains an acidic or basic polar group or an alcoholic hydroxyl group Developing toner,
<2> A step of dispersing at least the resin particles having the core-shell structure and the release agent particles in an aqueous medium, a step of aggregating the dispersed particles to obtain aggregated particles, and heating and aggregating the aggregated particles A method for producing a toner for developing an electrostatic charge image according to <1>, which comprises a step;
<3> The electrostatic charge image developing toner comprising the electrostatic charge image developing toner according to <1> or the electrostatic charge image developing toner produced by the production method according to <2>, and a carrier,
<4> A latent image forming step of forming an electrostatic latent image on the surface of the latent image holding member, and developing the electrostatic latent image formed on the surface of the latent image holding member with a developer containing toner to form a toner image. An image forming method comprising: a developing step, a transferring step for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and a fixing step for thermally fixing the toner image transferred to the surface of the transfer target The toner for developing an electrostatic charge image described in <1> above as the toner, the toner for developing an electrostatic charge image produced by the production method described in <2>, or the above <3 as the developer. An image forming method using the electrostatic charge image developer described in the above.

  According to the present invention, an electrostatic charge image developing toner capable of reducing fixing energy even on cardboard while achieving both high image quality and reliability, a manufacturing method thereof, and an electrostatic charge using the electrostatic charge image developing toner. An image developer and an image forming method can be provided.

The electrostatic image developing toner of the present invention is an electrostatic image developing toner obtained by agglomerating resin particles having a core-shell structure, and the resin constituting the core and the shell is an amorphous resin. The glass transition point of the resin constituting the core is different from the glass transition point of the resin constituting the shell by 20 ° C. or more, and the resin constituting the shell contains an acidic or basic polar group or an alcoholic hydroxyl group. It is characterized by that.
The present invention is described in detail below.

  In high-speed fixing using thick paper, the thermal energy consumed by the paper increases, so the temperature fluctuation of the fixing roll is likely to occur, and due to uneven temperature in and between the paper, uneven image gloss The image quality is likely to deteriorate, but the toner has a core-shell structure formed from a low-Tg resin and a high-Tg resin, and a combination of core-shell particles formed by pressure plasticization (Pressure Induced Miscibility). Fixing by normal temperature or low temperature heating, improving the uniformity of image gloss, reducing energy consumption related to toner fixation using cardboard in the GA area and reducing thermal stress on the cardboard, Suppresses the occurrence of curling and other cardboard damage.

When the high Tg resin and the low Tg resin form a micro phase separation state, the resin exhibits a plastic behavior with respect to pressure, and exhibits fluidity even in a normal temperature region under a certain pressure or higher. The resin is sometimes called baroplastic. Further, under a slight heating, such plasticization flow behavior is promoted, and the resin fluidity necessary for fixing can be obtained even under a lower pressure.
When such toner is used, it is difficult to fix on thick paper, which has conventionally been difficult unless the printing speed is reduced or a high heating temperature is set, with the same printing speed and temperature setting as when fixing to thin paper. Formation is possible.
In addition, in this way, fluidity is imparted to the toner when a pressure above a certain level is applied, and at a pressure lower than that, it behaves extremely solidly, so that the toner other than during thermal pressure fixing in the electrophotographic process is given. High reliability can be ensured in the development, transfer, and cleaning processes.
In addition, by providing high reliability, it is possible to use a toner having a small diameter such as 5 μm or less, which has been difficult to realize in the past, thereby reducing toner consumption and realizing a high-definition image. It is possible to achieve both image quality, reliability, and economy by reducing toner consumption.

In a conventional electrophotographic process, the maximum pressure at the time of pressure fixing in a fixing machine is usually 1 MPa or less, and is actually set in the range of 0.2 to 0.6 MPa in many cases.
In the present invention, it is fundamental that both low-temperature fixability and high reliability can be achieved by actively using the pressure plasticizing effect of the microphase separation resin composed of domains having different Tg depending on the fixing pressure. It is an effect.

(Static image developing toner)
<Binder resin>
[Core shell particles]
The electrostatic image developing toner (hereinafter also simply referred to as “toner”) of the present invention is obtained by aggregating resin particles having a core-shell structure (hereinafter also simply referred to as “core-shell particles”). The toner constituting the core and the shell are both non-crystalline resins, and the glass transition point (Tg) of the resin constituting the core and the Tg of the resin constituting the shell are different by 20 ° C. or more, The resin constituting the shell is characterized by containing an acidic or basic polar group or an alcoholic hydroxyl group.
In the resin constituting the core and the resin constituting the shell, the core or shell having a higher Tg is also referred to as a high Tg phase, and the core or shell having a lower Tg is also referred to as a low Tg phase.

The Tg of the high Tg phase is preferably 45 to 80 ° C, and more preferably 50 to 70 ° C.
When the Tg of the high Tg phase is 45 ° C. or more, the toner is excellent in storability, and it is difficult for filming to occur on the photoreceptor during caking or continuous printing in transportation or in a printer, It is preferable because image quality defects are less likely to occur. Further, it is preferable that the Tg of the high Tg phase is 80 ° C. or lower because the fixing temperature at the time of fixing (especially when fixing thick paper) is appropriate and damage to the recording medium such as curling is unlikely to occur.

  Further, it is important that the Tg of the low Tg phase is 20 ° C. or more lower than the Tg of the high Tg phase, preferably 30 ° C. or more. When the Tg difference between the high Tg phase and the low Tg phase is within 20 ° C., the pressure plasticization behavior becomes difficult to be observed, the fixing temperature at the time of fixing (particularly when fixing thick paper) becomes high, and the recording material such as curling is damaged. Invite.

The glass transition point of the resin can be measured by a known method, for example, by the method (DSC method) defined in ASTM D3418-82.
“Crystallinity” as shown in the crystalline resin means that in differential scanning calorimetry (DSC), it has a clear endothermic peak, not a step-like endothermic change. It means that the half-value width of the endothermic peak when measured at a rate of 10 ° C./min is within 6 ° C.
On the other hand, a resin having an endothermic peak with a half-value width exceeding 6 ° C. or a resin having no clear endothermic peak means non-crystalline (amorphous). The glass transition point by DSC of the amorphous resin is measured according to ASTM D3418 using a differential scanning calorimeter (DSC-50) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system. The measurement conditions are shown below.
Sample: 3-15 mg, preferably 5-10 mg
Measurement method: Place the sample in an aluminum pan, and use an empty aluminum pan as a reference.
Temperature curve: Temperature increase I (20 ° C. to 180 ° C., temperature increase rate 10 ° C./min)
The glass transition point is measured from the endothermic curve measured at the time of temperature rise in the above temperature curve. The glass transition point is a temperature at which the differential value of the endothermic peak curve is maximized.

In the emulsion polymerization, if a method called stepwise feeding a monomer called a two-stage feed is used, core-shell particles made of Tg resins having different cores and shells can be obtained.
However, if the core-shell particles are mixed and processed at a high temperature and high pressure as in the prior art for kneading, as in the prior art, the precisely formed phase separation structure is destroyed and the desired characteristics cannot be obtained. there is a possibility.
For this reason, a method of producing particles in an aqueous medium using water or the like is suitable as a method of producing this toner.
In order to use the resin obtained here as a binder resin to form a toner by a dissolution suspension method or an emulsion polymerization aggregation method, a conventionally known production method can be used.

  Core-Shell Polymer Nanoparticles for Baroplastic Processing, Macromolecules 2005, 38, 8036-8044, Preparation and Characterization of Core-Shell Particles Containing Perfluoroalkyl Acrylate in the Shell Macromolecules 2002, 35, 6811-6818, Complex Phase Behavior of a Weakly Interacting Binary Polymer Blend, Macromolecules 2004, 37, 5851-5855, and the like.

The resin that can be used for the core-shell particles that can be used in the present invention is an amorphous resin, and is not particularly limited as long as the Tg of the resin used for the core and the resin used for the shell is different by 20 ° C. or more. However, it is preferably a non-crystalline addition polymerization type resin, and more preferably a non-crystalline homopolymer or copolymer of an ethylenically unsaturated monomer.
Examples of monomers constituting these homopolymers or copolymers include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. (Meth) acrylic acid esters such as lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; Ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone, Sulfonyl ethyl ketone, vinyl ketones such as vinyl isopropenyl ketone; isoprene, butene, and the like olefins such as butadiene, beta-carboxyethyl acrylate can be preferably exemplified. A homopolymer composed of these monomers, a copolymer obtained by copolymerizing two or more of these, and a mixture thereof can be used.

Specific combinations of Tg of 20 ° C. or more that form a microphase separation structure include polystyrene and polybutyl acrylate, polystyrene and polybutyl methacrylate, polystyrene and poly (2-ethylhexyl acrylate), polystyrene and polyhexyl. Preferred examples include a combination of methacrylate, polyethyl methacrylate / polyethyl acrylate, polyisoprene / polybutylene and the like.
The core-shell particles by these combinations can observe the pressure plastic behavior regardless of which is the shell or the core. However, in order to make the toner compatible and have durability during transportation and storage, the shell side has a high Tg. It is preferred that the phases come.
Among these, it is particularly preferable that the resin used for the shell of the core-shell particles is composed of 80% by weight or more of styrenes, and the resin used for the core is composed of 80% by weight or more of acrylates.

The weight average molecular weight of the resin used for the core is preferably 3,000 to 50,000, and more preferably 5,000 to 40,000. The above range is preferable because both the fixing property and the image strength after fixing are easily compatible.
The weight average molecular weight of the resin used for the shell is preferably 3,000 to 50,000, and more preferably 5,000 to 40,000. The above range is preferable because it is easy to achieve both fixing properties and suppression of filming on the photoreceptor.

  The content of the core-shell particles is preferably 20% or more with respect to the total weight of the toner in order to achieve the object, more preferably in the range of 30 to 98%, and in the range of 50 to 98%. More preferably it is. The above range is preferable because the cardboard fixing property is good.

  Further, in order to use these particles in an amount of 50% by weight or more as a composition in the toner, it is necessary to give the particles controllability at the time of toner formation in an aqueous medium = particle size and particle size distribution controllability. For this purpose, it is effective to contain acidic or basic polar groups or alcoholic hydroxyl groups in the resin of the particles in order to facilitate control by adding a flocculant. These are mainly realized by copolymerizing a monomer (monomer) having these polar groups in the shell component.

Preferred examples of the acidic polar group include a carboxyl group, a sulfonic acid group, and an acid anhydride.
Examples of the monomer (monomer) for forming an acidic polar group in the resin include α, β-ethylenically unsaturated compounds having a carboxyl group or a sulfone group, and specifically include acrylic acid and methacrylic acid. Preference is given to fumaric acid, maleic acid, itaconic acid, cinnamic acid, sulfonated styrene, allylsulfosuccinic acid and the like.

Preferred examples of the basic polar group include an amino group, an amide group, and a hydrazide group.
Examples of the monomer (monomer) for forming a basic polar group in the resin include a monomer structural unit having the nitrogen atom (hereinafter sometimes referred to as “nitrogen-containing monomer”). Preferred examples of the compound used as the monomer structural unit include (meth) acrylic acid amide compounds, (meth) acrylic acid hydrazide compounds, and (meth) acrylic acid aminoalkyl compounds.

Examples of these monomers include (meth) acrylic acid amide compounds such as acrylic acid amide, methacrylic acid amide, acrylic acid methylamide, methacrylic acid methylamide, acrylic acid dimethylamide, acrylic acid diethylamide, acrylic acid phenylamide, and acrylic acid benzylamide. Etc.
Examples of the (meth) acrylic acid hydrazide compound include acrylic acid hydrazide, methacrylic acid hydrazide, methyl acrylate hydrazide, methyl methacrylate hydrazide, dimethyl acrylate hydrazide, and phenyl hydrazide acrylate.
In addition, examples of the aminoalkyl (meth) acrylate compound include 2-aminoethyl acrylate and 2-aminoethyl methacrylate.

  As a monomer (monomer) for forming an alcoholic hydroxyl group, hydroxy acrylates are preferable. Specifically, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate Etc.

  The preferable content of the monomer having a polar group is preferably in the range of 0.01 to 20% by weight, more preferably in the range of 0.1 to 10% by weight based on the total weight of the polymerizable monomers used in the shell layer. preferable. Within the above range, the controllability at the time of toner formation in the aqueous medium can be imparted to the core-shell particles.

The polymerization reaction may be performed using an aqueous medium.
Examples of the aqueous medium that can be used in the present invention include water such as distilled water and ion exchange water, and alcohols such as ethanol and methanol. Among these, ethanol and water are preferable, and water such as distilled water and ion-exchanged water is particularly preferable. These may be used individually by 1 type and may use 2 or more types together.
The aqueous medium may contain a water-miscible organic solvent. Examples of the water-miscible organic solvent include acetone and acetic acid.

The polymerization reaction may be performed using an organic solvent.
Specific examples of the organic solvent that can be used in the present invention include hydrocarbon solvents such as toluene, xylene, mesitylene, chlorobenzene, bromobenzene, iodobenzene, dichlorobenzene, 1,1,2,2-tetrachloroethane. Halogen solvents such as p-chlorotoluene, ketone solvents such as 3-hexanone, acetophenone and benzophenone, dibutyl ether, anisole, phenetole, o-dimethoxybenzene, p-dimethoxybenzene, 3-methoxytoluene, dibenzyl ether, Ether solvents such as benzyl phenyl ether, methoxynaphthalene and tetrahydrofuran, thioether solvents such as phenyl sulfide and thioanisole, ethyl acetate, butyl acetate, pentyl acetate, methyl benzoate, methyl phthalate, phthalic acid Ester solvents such as chill and cellosolve acetate, diphenyl ether, or alkyl-substituted diphenyl ethers such as 4-methylphenyl ether, 3-methylphenyl ether, and 3-phenoxytoluene, or 4-bromophenyl ether, 4-chlorophenyl ether, 4 -Halogen-substituted diphenyl ethers such as bromodiphenyl ether and 4-methyl-4'-bromodiphenyl ether, or alkoxy such as 4-methoxydiphenyl ether, 4-methoxyphenyl ether, 3-methoxyphenyl ether, 4-methyl-4'-methoxydiphenyl ether Diphenyl ether solvents such as substituted diphenyl ethers or cyclic diphenyl ethers such as dibenzofuran and xanthene may be mentioned, and these may be used as a mixture.

  In the core-shell particles, the weight ratio of the resin constituting the core and the resin constituting the shell is preferably core: shell = 10: 90 to 90:10, and preferably 20:80 to 80:20. More preferred. The above range is preferable because the cardboard fixing property is good.

The median diameter of the core-shell particles is preferably 1/2 to 1/1000, more preferably 1/5 to 1 / 1,000 with respect to the volume average particle diameter of the toner. More preferably, it is 10-1 / 200. The above range is preferable because the toner particle size is easy.
The median diameter of the core-shell particles is preferably 0.01 to 1.0 μm , more preferably 0.05 to 0.7 μm , and further preferably 0.1 to 0.5 μm. . It is preferable that the average particle size of the core-shell particles is in the above range because the toner particle size distribution can be easily controlled.
In addition, the median diameter of the core-shell particles can be measured by a known method, and for example, it can be measured with a laser diffraction type particle size distribution measuring apparatus (LA-920, manufactured by Horiba, Ltd.).

  The method for confirming that there are a plurality of core-shell particles contained in the toner is not particularly limited, and a method of observing the cross section of the toner with a transmission electron microscope, or clarifying the contrast by dyeing or the like. The method of observing a cross section with a scanning electron microscope, etc. are mentioned. In some cases, it is clear that there are two or more core-shell particles contained in the toner from the ratio of the toner particle diameter to the core-shell particles at the time of manufacture, the amount of core-shell particles used, the production method, and the like.

These pressure plastic core-shell particles can be used alone as a binder resin, or resin particles obtained by conventional emulsion polymerization can be mixed and used.
In this case, the ratio of the core-shell particles is preferably 30% by weight or more based on the total binder resin used in the toner in order to achieve the object, and more preferably in the range of 40 to 100% by weight. More preferably, it is in the range of 50 to 100% by weight.

In the present invention, a polycondensation or polymerization reaction between a monomer and a prepolymer of a monomer prepared in advance can also be included. The prepolymer is not limited as long as it is a polymer that can be melted or uniformly mixed with the monomer.
Furthermore, the binder resin that can be used in the present invention is a homopolymer of the above-described monomer, a copolymer obtained by combining two or more monomers including the above-described monomer, or a mixture or graft thereof. The polymer may have a partially branched or crosslinked structure.

A crosslinking agent may be added to the binder resin that can be used in the present invention as necessary to form a crosslinked resin. A typical cross-linking agent is a polyfunctional monomer having two or more ethylenically unsaturated groups in the molecule.
Specific examples of such crosslinking agents include aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate / trivinyl, and naphthalene dicarboxylic acid. Polyvinyl esters of aromatic polyvalent carboxylic acids such as divinyl acid and diphenyl biphenyl carboxylate; Divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridine dicarboxylate; Vinyl pyromutate, vinyl furan carboxylate, pyrrole-2- Vinyl esters of unsaturated heterocyclic compounds such as vinyl carboxylate and vinyl thiophenecarboxylate; butanediol methacrylate, hexanediol acrylate, octanediol methacrylate, decanediol acrylate (Meth) acrylic acid esters of linear polyhydric alcohols such as dodecanediol methacrylate; branches such as neopentylglycol dimethacrylate and 2-hydroxy-1,3-diacryloxypropane; ) Acrylic acid esters; Polyethylene glycol di (meth) acrylate, Polypropylene polyethylene glycol di (meth) acrylates; Divinyl succinate, divinyl fumarate, vinyl / divinyl maleate, divinyl diglycolate, vinyl / divinyl itaconate, acetone Divinyl dicarboxylate, divinyl glutarate, divinyl 3,3′-thiodipropionate, trans-aconite divinyl / trivinyl, divinyl adipate, divinyl pimelate, divinyl suberate, dibi azelate Le, sebacate, divinyl dodecanedioate divinyl, polyfunctional vinyl esters of polycarboxylic acids such as oxalic acid divinyl and the like.

In the present invention, these crosslinking agents may be used alone or in combination of two or more. Among the above crosslinking agents, as the crosslinking agent in the present invention, (meth) acrylic acid esters of linear polyhydric alcohols such as butanediol methacrylate, hexanediol acrylate, octanediol methacrylate, decanediol acrylate, and dodecanediol methacrylate are used. Branched chains such as neopentyl glycol dimethacrylate and 2-hydroxy-1,3-diacryloxypropane, (meth) acrylic acid esters of substituted polyhydric alcohols; polyethylene glycol di (meth) acrylate, polypropylene polyethylene glycol di ( It is preferable to use (meth) acrylates.
The content of the crosslinking agent is preferably 0.05 to 5% by weight, more preferably 0.1 to 1.0% by weight, based on the total amount of polymerizable monomers.

Among the binder resins used in the toner of the present invention, those that can be produced by radical polymerization of a polymerizable monomer can be polymerized using a radical polymerization initiator.
There is no restriction | limiting in particular as a radical polymerization initiator used here. 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, tert-butyl hydroperoxide pertriphenyl acetate, tert-butyl formate, Peroxides such as tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl permethoxyacetate, tert-butyl perN- (3-toluyl) carbamate, 2,2 '-Azobispro Bread, 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 -Methylbutyronitrile-3-sodium sulfonate), 2- (4-methylphenylazo) -2-methylmalonodinitrile, 4,4'-azobis-4-cyanovaleric acid, 3,5-dihydroxymethylphenyl Zo-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-Nitrophenylazobenzylcyanoacetate, phenylazodiphenylmethane, phenylazotriphenylmethane, 4-nitrophenylazotrif Nylmethane, 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.

  Further, in the production of the binder resin, when polycondensation and / or polymerization is performed in an aqueous medium, in order to form a monomer particle emulsion, for example, a monomer solution to which a co-surfactant is added ( (Oil phase) and aqueous medium solution of surfactant (aqueous phase) are subjected to shear mixing using a piston homogenizer, microfluidizer (eg, Microfluid, “Microfluidizer” manufactured by Dix), ultrasonic disperser, etc. A method of uniformly mixing and emulsifying with an apparatus can be exemplified. In that case, it is preferable that the preparation amount of the oil phase with respect to the water phase is about 0.1 to 50% by weight with respect to the total amount of the water phase and the oil phase. The amount of the surfactant used is preferably less than the critical micelle concentration (CMC) in the presence of the emulsion to be formed, and the amount of the cosurfactant used is preferably 100 parts by weight of the oil phase. Is 0.1 to 40 parts by weight, more preferably 0.1 to 20 parts by weight.

  As described above, the “mini” is a polymerization of the monomer in the presence of the polymerization initiator of the monomer emulsion by the combined use of the surfactant amount less than the critical micelle concentration (CMC) and the co-surfactant. The “emulsion polymerization method” is preferable because uniform polymer particles are formed because the addition polymerizable monomer is polymerized in the monomer particles (oil droplets). Further, in the present invention, even in the polycondensable / addition polymerizable composite polymer, the “miniemulsion polymerization method” does not require monomer diffusion in the polymerization process. It has the advantage that it can be present in the particles.

  Further, for example, a particle size of 5 to 50 nm described in JS Guo, MS El-Aasser, JW Vanderhoff; J. Polym. Sci .: Polym. Chem. Ed., 27, 691 (1989), etc. The so-called “microemulsion polymerization method” of these particles has the same dispersion structure and polymerization mechanism as the “miniemulsion polymerization method” in the present invention, and can be used in the present invention. The “microemulsion polymerization method” uses a large amount of a surfactant having a critical micelle concentration (CMC) or more, and a large amount of the surfactant is mixed in the obtained polymer particles or the removal thereof. For this reason, there may be a problem that a long time is required for a process such as water cleaning, acid cleaning, or alkali cleaning.

Further, when polycondensation and / or polymerization is carried out in an aqueous medium in the production of the binder resin, it is preferable to use a co-surfactant, and 0.1 to 40% by weight of the co-interface with respect to the total amount of monomers. More preferably, an activator is used. Co-surfactants are added to reduce Ostwald ripening in so-called miniemulsion polymerization. As the co-surfactant, generally known co-surfactants can be used in the mini-emulsion method.
Examples of suitable co-surfactants include alkanes having 8 to 30 carbon atoms such as dodecane, hexadecane and octadecane, alkyl alcohols having 8 to 30 carbon atoms such as lauryl alcohol, cetyl alcohol and stearyl alcohol, lauryl mercaptan, C8-C30 alkyl mercaptans such as cetyl mercaptan and stearyl mercaptan, and other polymers such as acrylic esters and methacrylic esters and their polymers, polystyrene and polyester, polyadducts, carboxylic acids and ketones Amines and the like, but is not limited thereto.

Among the co-surfactants exemplified above, those preferably used are hexadecane, cetyl alcohol, stearyl methacrylate, lauryl methacrylate, polyester, and polystyrene. In particular, for the purpose of avoiding the generation of volatile organic substances, stearyl methacrylate, lauryl methacrylate, polyester, and polystyrene are more preferable.
The polymer and the composition containing a polymer that can be used for the cosurfactant can include, for example, a copolymer with another monomer, a block copolymer, a mixture, and the like. A plurality of co-surfactants can also be used in combination.
The co-surfactant can be added to both the oil phase and the aqueous phase.

  In the production of the toner of the present invention, for example, stabilization at the time of dispersion in the suspension polymerization method, resin particle dispersion, colorant particle dispersion, release agent particle dispersion in the emulsion polymerization aggregation method, etc. A surfactant can be used for the purpose of stabilizing the dispersion of the composition.

  Examples of the surfactant include anionic surfactants such as sulfate, 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 the toner of the present invention, an anionic surfactant generally has a strong dispersing power and is excellent in dispersing resin particles and colorants. Moreover, it is advantageous to use an anionic surfactant as the surfactant for dispersing the release agent.
The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of anionic surfactants include fatty acid soaps such as potassium laurate, sodium oleate, and castor oil sodium; sulfate esters such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, and nonyl phenyl ether sulfate; lauryl sulfonate , Sodium alkylnaphthalene sulfonate such as dodecylbenzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate; sulfones such as naphthalene sulfonate formalin condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate, lauric acid amide sulfonate, oleic acid amide sulfonate Acid salts; lauryl phosphate, isopropyl phosphate, nonylphenyl ether Phosphoric acid esters such as Sufeto; dialkyl sulfosuccinate salts such as sodium dioctyl sulfosuccinate; sulfosuccinate salts such as sulfosuccinate lauryl disodium; 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, distearyldimethylammonium chloride, distearyldimethylammonium chloride, lauryldihydroxyethylmethylammonium chloride, oleylbispolyoxyethylenemethylammonium chloride, lauroylaminopropyldimethylethylammonium ethosulphate, lauroylaminopropyldimethylhydroxyethylammonium perchlorate, alkylbenzene Trimethylammonium chloride, Quaternary ammonium salts such as quilts trimethyl ammonium 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 may be a level that does not inhibit the present invention, generally a small amount, specifically in the range of 0.01 to 3% by weight, and more. Preferably it is the range of 0.05-2 weight%, More preferably, it is the range of 0.1-2 weight%. When the content is within the above range, each dispersion such as a resin particle dispersion, a colorant particle dispersion, and a release agent particle dispersion is stable, and aggregation and release of specific particles do not occur. The effect of the present invention can be sufficiently obtained without affecting the amount of the compound added. In general, a suspension-polymerized toner dispersion having a large particle size is stable even when a small amount of a surfactant is used.

As the dispersion stabilizer used in the suspension polymerization method or the like, a slightly water-soluble and hydrophilic inorganic fine powder can be used. Examples of the inorganic fine powder that can be used include silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate (hydroxyapatite), clay, diatomaceous earth, bentonite and the like. Among these, calcium carbonate, tricalcium phosphate, and the like are preferable from the viewpoints of easy particle size formation and removal.
Also, an aqueous polymer that is solid at room temperature can be used as a dispersion stabilizer. Specifically, cellulose compounds such as carboxymethyl cellulose and hydroxypropyl cellulose, polyvinyl alcohol, gelatin, starch, gum arabic and the like can be used.

[Other binder resins]
In the toner for developing an electrostatic charge image of the present invention, other binder resins can be used as the binder resin in addition to the core-shell particles.
Examples of other binder resins include ethylene resins, styrene resins, polymethyl methacrylate, (meth) acrylic resins, polyamide resins, polycarbonate resins, polyether resins, polyester resins, and copolymer resins thereof. More preferred are styrene resins, (meth) acrylic resins, polyester resins, and copolymer resins thereof.
As a polyester resin, the polyester which can be used for the core-shell particle mentioned above can be mentioned preferably. As a method for producing a polyester resin, in addition to the above-described methods, for example, “polycondensation” (Chemical Doujin, 1971), “Polymer Experimental Studies (Polycondensation and Polyaddition)” (Kyoritsu Shuppan, 1958) and “ Polyester resin handbook "(edited by Nikkan Kogyo Shimbun, published in 1988) can be synthesized using a conventionally known method, and a transesterification method or a direct polycondensation method can be used alone or in combination. Can be synthesized.

Moreover, addition polymerization type resins are also useful as other binder resins that can be used in the present invention. Examples of the addition polymerizable monomer for producing the addition polymerization type resin include a radical polymerizable monomer, a cationic polymerizable monomer, and an anion polymerizable monomer, which are radical polymerizable monomers. It is preferable that it is an ethylenically unsaturated monomer. Preferred examples of the radical polymerization resin include styrene resins and (meth) acrylic resins, particularly styrene- (meth) acrylic copolymer resins.
Examples of the styrene- (meth) acrylic copolymer resin include 60 to 90 parts by weight of an aromatic monomer (styrene monomer) having an ethylenically unsaturated group, and an ethylenically unsaturated carboxylic acid ester monomer. (Copolymer) obtained by polymerizing a monomer mixture consisting of 10 to 40 parts by weight of (meth) acrylic acid ester monomer and 1 to 3 parts by weight of ethylenically unsaturated acid monomer Latex dispersed and stabilized with an agent can be preferably used. It is preferable that the glass transition point of said copolymer is 50-70 degreeC.

The polymerizable monomers that can be suitably used in the production of other binder resins that can be used in the present invention will be described below.
Examples of the styrene monomer include styrene, vinyl naphthalene, alkyl having an alkyl chain such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene. Examples include halogen-substituted styrene such as substituted styrene, 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and fluorine-substituted styrene such as 4-fluorostyrene and 2,5-difluorostyrene. Styrene is preferred as the styrene monomer.

Examples of the (meth) acrylate monomer include n-methyl (meth) acrylate, n-ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, ( N-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, n-decyl (meth) acrylate, n (meth) acrylate -Dodecyl, n-lauryl (meth) acrylate, n-tetradecyl (meth) acrylate, n-hexadecyl (meth) acrylate, n-octadecyl (meth) acrylate, isopropyl (meth) acrylate, (meth) acryl Isobutyl acid, t-butyl (meth) acrylate, isopentyl (meth) acrylate, amyl (meth) acrylate, (meth) acrylic acid Pentyl, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, biphenyl (meth) acrylate, (meth) acryl Diphenylethyl acid, t-butylphenyl (meth) acrylate, terphenyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, (meth Examples thereof include diethylaminoethyl acrylate, methoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, β-carboxyethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylamide and the like. As the (meth) acrylic acid ester monomer, n-butyl acrylate is preferable.
Here, the notation of “(meth) acrylic acid ester” is an abbreviated notation indicating that both structures of methacrylic acid ester and acrylic acid ester can be taken.

The ethylenically unsaturated acid monomer is an ethylenically unsaturated monomer containing an acidic group such as a carboxyl group, a sulfonic acid group, or an acid anhydride.
When the carboxyl group is contained in the styrene resin, (meth) acrylic acid ester resin and styrene- (meth) acrylic acid ester copolymer resin, it is copolymerized with a polymerizable monomer having a carboxyl group. Obtainable.

  Specific examples of such a carboxyl group-containing polymerizable monomer include acrylic acid, aconitic acid, atropic acid, allylmalonic acid, angelic acid, isocrotonic acid, itaconic acid, 10-undecenoic acid, elaidic acid, erucic acid, olein. Acid, ortho-carboxycinnamic acid, crotonic acid, chloroacrylic acid, chloroisocrotonic acid, chlorocrotonic acid, chlorofumaric acid, chloromaleic acid, cinnamic acid, cyclohexenedicarboxylic acid, citraconic acid, hydroxycinnamic acid, dihydroxysilicic acid Cinnamic acid, tiglic acid, nitrocinnamic acid, vinyl acetic acid, phenyl cinnamic acid, 4-phenyl-3-butenoic acid, ferulic acid, fumaric acid, brassic acid, 2- (2-furyl) acrylic acid, bromocinnamic acid, Bromofumaric acid, bromomaleic acid, benzylidene malonic acid, benzo Examples include acrylic acid, 4-pentenoic acid, maleic acid, mesaconic acid, methacrylic acid, methylcinnamic acid, methoxycinnamic acid, etc., and acrylic acid, methacrylic acid, maleic acid, cinnamic acid due to the ease of polymer formation reaction, etc. Acid, fumaric acid and the like are preferable, and acrylic acid is more preferable.

The weight average molecular weight of the addition polymerization type resin used as the other binder resin is preferably 5,000 to 50,000, and more preferably 8,000 to 40,000.
When the molecular weight is within the above range, it is preferable because the powder characteristics of the toner at normal temperature can be kept good and offset of the fixed image can be prevented at high temperature fixing.

The glass transition point of other binder resins is preferably 45 to 65 ° C, and more preferably 50 to 65 ° C.
When the glass transition point is within the above range, it is preferable because deterioration of the powder characteristics due to the release agent can be prevented, and bleeding of the release agent during fixing can be facilitated.

<Charge control agent>
If necessary, a charge control agent may be added to the toner of the present invention.
Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength (%) and reducing wastewater contamination. The toner of the present invention may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

<Flocculant>
When the emulsion aggregation and coalescence method is used in the production of the toner in the present invention, the aggregation can be generated by the pH change in the aggregation process to prepare particles. At the same time, an aggregating agent may be added to stably and rapidly aggregate the particles, or to obtain aggregated particles having a narrower particle size distribution.
As the flocculant, a compound having a monovalent or higher charge is preferable. Specific examples of the compound include water-soluble surfactants such as the above-mentioned ionic surfactants and nonionic surfactants, hydrochloric acid, sulfuric acid, Acids such as nitric acid, acetic acid, oxalic acid, magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, sodium carbonate and other inorganic acid metal salts, sodium acetate, potassium formate, oxalic acid Aliphatic acids such as sodium, sodium phthalate and potassium salicylate, metal salts of aromatic acids, metal salts of phenols such as sodium phenolate, metal salts of amino acids, triethanolamine hydrochloride and aniline hydrochloride And inorganic acid salts of aromatic amines.

In consideration of the stability of the aggregated particles, the stability of the coagulant with respect to heat and time, and the removal during washing, a metal salt of an inorganic acid is preferable as the coagulant in terms of performance and use. Specific examples include metal salts of inorganic acids such as magnesium chloride, sodium chloride, aluminum sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, and sodium carbonate.
The amount of the flocculant added varies depending on the valence of the charge, but all of them are small, and in the case of monovalent, about 3% by weight or less with respect to the total amount of toner, and in the case of divalent, about 1% by weight or less. In the case of trivalent, it is about 0.5% by weight or less. Since the amount of the flocculant is preferably small, it is preferable to use a compound having a large valence.

<Colorant>
There is no restriction | limiting in particular as a coloring agent which can be used for this invention, A well-known coloring agent is mentioned, According to the objective, it can select suitably. One colorant may be used alone, or two or more colorants of the same system may be mixed and used. Further, two or more kinds of different colorants may be mixed and used. Further, these colorants may be used after surface treatment.

Specific examples of the colorant include black, yellow, orange, red, blue, purple, green, and white colorants as shown below.
Examples of the black pigment include organic and inorganic colorants such as carbon black, aniline black, activated carbon, nonmagnetic ferrite, and magnetite.
Yellow pigments include yellow lead, zinc yellow, yellow calcium oxide, cadmium yellow, chrome yellow, fast yellow, fast yellow 5G, fast yellow 5GX, fast yellow 10G, benzidine yellow G, benzidine yellow GR, selenium yellow, quinoline yellow, Permanent yellow NCG can be exemplified.
Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, benzidine orange G, indanthrene brilliant orange RK, indanthrene brilliant orange GK and the like.
Red pigments include Bengala, cadmium red, red lead, mercury sulfide, watch young red, permanent red 4R, risor red, brilliantamine 3B, brilliantamine 6B, dapon oil red, pyrazolone red, rhodamine B rake, lake red C Rose Bengal, Eoxin Red, Alizarin Lake and the like.
Examples of blue pigments include organic and inorganic colorants such as bitumen, cobalt blue, alkali blue lake, Victoria blue lake, fast sky blue, indanthrene blue BC, ultramarine blue, phthalocyanine blue, and phthalocyanine green. .
Examples of purple pigments include organic and inorganic colorants such as manganese purple, fast violet B, and methyl violet lake.
Examples of the green pigment include organic and inorganic colorants such as chromium oxide, chromium green, pigment green B, malachite green lake, and fanal yellow green G.
Examples of white pigments include zinc white, titanium oxide, antimony white, and zinc sulfide.
Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.

<Dispersing method of coloring agent>
The colorant in the toner of the present invention can be dispersed in the binder resin using a known method. If the toner is based on a kneading and pulverizing method, it may be used as it is, or a so-called master batch that is previously dispersed in a resin at a high concentration and then kneaded with a binder resin at the time of kneading may be used. You may use the flushing disperse | distributed in resin in the state of the wet cake before drying after a coloring agent synthesis | combination.
The above-mentioned colorant can be used as it is for toner preparation by suspension polymerization. In suspension polymerization, the colorant dispersed in a resin is dissolved or dispersed in a polymerizable monomer. The colorant can be dispersed in the granulated particles.

When the toner production method is an emulsion polymerization aggregation method, a colorant dispersion is prepared by dispersing the colorant in an aqueous medium together with a dispersant such as a surfactant by mechanical impact, etc. It can be obtained by agglomerating together and granulating to a toner particle size.
Specific examples of the colorant dispersion by mechanical impact or the like include, for example, a rotary shear type homogenizer, a ball type mill, a sand mill, an attritor or other media type disperser, a high pressure opposed collision type disperser, etc. A dispersion can be prepared. Further, these colorants can be dispersed in an aqueous system by a homogenizer using a polar surfactant.

  The colorant is preferably added in the range of 4 to 15% by weight, preferably in the range of 4 to 10% by weight, based on the total solid content of the toner, in order to ensure color developability at the time of fixing. Is more preferable. However, when a magnetic material is used as the black colorant, it is preferably added in the range of 12 to 48% by weight, and more preferably in the range of 15 to 40% by weight. Each color toner such as yellow toner, magenta toner, cyan toner, black toner, white toner, and green toner can be obtained by appropriately selecting the type of the colorant.

<Release agent>
A release agent may be added to the toner of the present invention as necessary. The release agent is generally used for the purpose of improving the releasability.
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; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc. Examples include mineral / petroleum waxes; ester waxes such as fatty acid esters, montanic acid esters, and carboxylic acid esters. In this invention, these mold release agents may be used individually by 1 type, and may use 2 or more types together.

  The amount of these release agents added is preferably 1 to 20% by weight, more preferably 5 to 15% by weight, based on the total amount of toner particles. Within the above range, the effect of the release agent is sufficient, and the toner particles are not easily destroyed inside the developing machine, so the spent of the release agent to the carrier does not occur, and the charge is difficult to decrease. .

<Magnetic material>
The toner for developing an electrostatic charge image of the present invention may contain a magnetic material as necessary.
As the magnetic material, ferrite, magnetite and other iron, cobalt, nickel and other metals or alloys exhibiting ferromagnetism, compounds containing these elements, or containing no ferromagnetic elements, but by performing an appropriate heat treatment Mention may be made of alloys that exhibit ferromagnetism, such as alloys of the type called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, or chromium dioxide. For example, in the case of obtaining a black toner, it is particularly preferable to use magnetite which is black in itself and also functions as a colorant. In the case of obtaining a color toner, a toner having a small blackness such as metallic iron is preferable. Some of these magnetic materials also function as a colorant, and in that case, they may also be used as a colorant. When the magnetic toner is used, the content of these magnetic materials is preferably 20 to 70 parts by weight, more preferably 40 to 70 parts by weight per 100 parts by weight of the toner.

<Internal additive>
In the toner of the present invention, an internal additive may be added inside the toner. The internal additive is generally used for the purpose of controlling the viscoelasticity of the fixed image.
Specific examples of the internal additive include inorganic particles such as silica and titania, organic particles such as polymethyl methacrylate, and surface treatment may be performed for the purpose of improving dispersibility. These may be used alone or in combination of two or more internal additives.

<External additive>
An external additive such as a fluidizing agent or a charge control agent may be added to the toner of the present invention.
External additives include silica particles, titanium oxide particles, alumina particles, cerium oxide particles, inorganic particles such as carbon black, and polymer particles such as polycarbonate, polymethyl methacrylate, and silicone resin whose surfaces are treated with a silane coupling agent. Known materials such as amine metal salts and salicylic acid metal complexes can be used. The external additives that can be used in the present invention may be used alone or in combination of two or more.

The cumulative volume average particle size D ₅₀ of the toner of the present invention is preferably in the range of 3.0 to 9.0 μm, more preferably in the range of 3.0 to 5.0 μm. It is preferable that D ₅₀ is 3.0 μm or more because the adhesive force is appropriate and the developability is good. Further, it is preferable that D ₅₀ is 9.0 μm or less because the resolution of the image is excellent.
The volume average particle size distribution index GSDv of the toner of the present invention is preferably 1.30 or less. A GSDv of 1.30 or less is preferable because the resolution is good, toner scattering and fogging hardly occur, and image defects hardly occur.

The cumulative volume average particle diameter D ₅₀ and the average particle size distribution index of the toner of the present invention are measured by a measuring instrument such as Coulter Counter TAII (manufactured by Nikka Kisha Co., Ltd.), Multisizer II (manufactured by Nikka Kisha Co., Ltd.), or the like. For the particle size range (channel) divided based on the particle size distribution, draw the cumulative distribution from the small diameter side for the volume and number, respectively, and the particle size to be 16% is the volume D _16v , number D _16P , 50% cumulative _{Are defined} as a volume D _50v and a number D _50P , and a particle diameter at a cumulative 84% is defined as a volume D _84v and a number D _84P . Using these, the volume average particle size distribution index (GSDv) is calculated as (D _84v / D _16V ) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D _84P / D _16P ) ^1/2 .

The toner shape factor SF1 is preferably in the range of 110 to 140, more preferably 120 to 140. It is well known that spherical toner is more easily transferred in the transfer process in the electrophotographic process, and that irregular toner is easier to clean in the cleaning process.
SF1 is a shape factor indicating the degree of unevenness on the toner particle surface, and is calculated as follows. The toner shape factor SF1 is obtained by taking an optical microscope image of toner dispersed on a slide glass into a Luzex image analyzer through a video camera, and calculating the square of the maximum length of toner particles per 50 toner particles / projection area ((ML)). ² / A), SF1 of the following formula is calculated, and the average value is obtained.

式中、ＭＬはトナー粒子の最大長を示し、Ａは粒子の投影面積を示す。

In the formula, ML represents the maximum length of toner particles, and A represents the projected area of the particles.

(Method for producing toner for developing electrostatic image)
As a method for producing the toner for developing an electrostatic charge image of the present invention, a mechanical production method such as a pulverization method, or a resin particle dispersion is produced using the binder resin, and a toner is produced from the resin particle dispersion. The toner can be manufactured by a so-called chemical manufacturing method. The toner of the present invention may be a so-called pulverized toner or polymerized toner, but is preferably a polymerized toner.
The method for producing the toner for developing an electrostatic charge image of the present invention is not particularly limited as long as it is a known method such as a kneading pulverization method, an emulsion polymerization aggregation method, or a suspension polymerization method, but an emulsion polymerization aggregation is particularly preferable. Is the law.
The method for producing an electrostatic charge image developing toner of the present invention is an emulsion polymerization aggregation method in which the resin particles are aggregated in a dispersion containing at least binder resin particles to obtain aggregated particles (hereinafter referred to as “aggregation step”). And a step of heating and aggregating the aggregated particles (hereinafter also referred to as “fusion step”).

In the aggregation process, it is preferable to use a binder resin as a binder resin particle dispersion.
The method for dispersing and granulating the binder resin in the aqueous medium can be selected from known methods such as forced emulsification, self-emulsification, and phase inversion emulsification. Of these, the self-emulsification method and the phase inversion emulsification method are preferably applied in consideration of the energy required for emulsification, the particle size controllability of the obtained emulsion, stability, and the like.
The self-emulsification method and the phase inversion emulsification method are described in “Application Technology of Ultrafine Particle Polymer (CMC Publishing)”. As the polar group used for self-emulsification, a carboxyl group, a sulfone group and the like can be used.

In preparing other binder resin dispersions, an organic solvent may be used. When an organic solvent is used, it is preferable to remove a part of the organic solvent and form resin particles.
For example, after emulsifying the binder resin-containing material, it is preferable to solidify as particles by removing a part of the organic solvent. As a specific method of solidification, after the polycondensation resin-containing material is emulsified and dispersed in an aqueous medium, while stirring the solution, an inert gas such as air or nitrogen is fed into the organic solvent at the gas-liquid interface. A method of drying (waste wind drying method), a method of drying while maintaining a reduced pressure and bubbling an inert gas as necessary (a reduced pressure topping method), and further a polycondensation resin-containing material in an aqueous medium There is a method in which an emulsified dispersion liquid emulsified and dispersed or an emulsion liquid containing a polycondensation resin is discharged from the pores in a shower-like manner and dropped into a dish-shaped receiver and dried while repeating this (shower-type solvent removal method). . It is preferable to remove the solvent by selecting or combining these methods as appropriate based on the evaporation rate of the organic solvent to be used, the solubility in water, and the like.

The median diameter (center diameter) of the resin particle dispersion is preferably 0.05 μm or more and 2.0 μm or less, more preferably 0.1 μm or more and 1.5 μm or less, and further preferably 0.1 μm or more and 1.0 μm. It is as follows. This median diameter within the above range is preferable because the dispersion state of the resin particles in the aqueous medium is stabilized as described above. Further, when used for toner preparation, it is preferable because the particle size can be easily controlled and the releasability and the offset property during fixing are excellent.
The median diameter of the resin particles can be measured, for example, with a laser diffraction particle size distribution measuring device (LA-920, manufactured by Horiba, Ltd.).

  The aggregating method in the aggregating step is not particularly limited, and the aggregating method conventionally used in the emulsion polymerization aggregating method of electrostatic charge image developing toner, for example, by temperature increase, pH change, salt addition, etc. A method of reducing the stability of the emulsion and stirring with a disperser or the like is used.

  In the aggregation step, for example, the resin particle dispersion, the colorant dispersion, and, if necessary, the particles in the release agent dispersion are aggregated to form aggregated particles having a toner particle size. Can be formed. The agglomerated particles are formed by heteroaggregation or the like, and for the purpose of stabilizing the agglomerated particles and controlling the particle size / size distribution, monovalent ionic surfactants or metal salts having a polarity different from the agglomerated particles are used. Compounds having the above charges can be added.

  In the agglomeration step, for example, oil droplets emulsified and dispersed in an aqueous phase are formed into resin polymer particles by polymerizing monomers in the oil droplets in the presence of a polymerization initiator, A known agglomeration that agglomerates (associates) the formed polymer particles with particles containing at least colorant particles (if the colorant is previously added to the resin in the polymerization step, the color particles themselves) It is possible to adjust the toner particle size and distribution by aggregating (associating) by the method. Preferably, the production of toner particles in an emulsion polymerization aggregation method is used. Specifically, the obtained resin particle dispersion is mixed with a colorant particle dispersion, a release agent particle dispersion, etc., and an aggregating agent is further added to produce heteroaggregation, thereby aggregating particles having a toner diameter. It can be obtained by forming, and then heating to a temperature above the glass transition point or above the melting point of the resin particles to fuse and coalesce the aggregated particles, and wash and dry. In this manufacturing method, the toner shape can be controlled from an indeterminate shape to a spherical shape by selecting a heating temperature condition.

  In the aggregation step, it is possible to mix two or more types of resin particle dispersions and perform the steps after the aggregation. At that time, the resin particle dispersion is pre-aggregated to form first aggregated particles, and then another resin particle dispersion is added to form a second shell layer on the surface of the first aggregated particles. It is also possible to make multiple layers. Naturally, it is also possible to produce multilayer particles in the reverse order of the above example.

  Further, after the agglomeration treatment, the particle surface may be cross-linked by heat treatment or the like for the purpose of suppressing colorant exudation from the particle surface. In addition, you may remove the used surfactant etc. by water washing | cleaning, acid washing | cleaning, or alkali washing | cleaning as needed.

In the fusing step, the binder resin in the aggregated particles melts at a temperature equal to or higher than its melting point or glass transition point, and the aggregated particles change from an indeterminate shape to a more spherical shape.
In order to maintain the phase separation structure in the toner by the core-shell particles, it is preferable that the resin used for the shell is melted under a condition within + 50 ° C. of the glass transition point of the resin. When fused under the condition that the glass transition point of the resin used for the shell is within + 50 ° C, the viscosity of the core component is less likely to occur, the coalescence of the core resins hardly proceeds, the micro phase separation structure can be maintained, and the pressure This is preferable because the plastic behavior is sufficient.
Thereafter, the aggregate is separated from the aqueous medium, and washed and dried as necessary to form toner particles.

  After completion of the aggregation step and the fusion step, a desired toner may be obtained through an arbitrary washing step, solid-liquid separation step, and drying step. In the washing step, it is preferable to sufficiently perform substitution washing with ion-exchanged water from the viewpoint of chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, and the like are preferably used from the viewpoint of productivity. Further, although the drying process is not particularly limited, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

(Electrostatic image developer)
The electrostatic image developing toner of the present invention described above can be used as an electrostatic image developer. The developer is not particularly limited except that it contains the toner for developing an electrostatic image, and can have an appropriate component composition depending on the purpose. When the electrostatic image developing toner 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.
The carrier that can be used in the present invention is not particularly limited. Usually, magnetic particles such as iron powder, ferrite, iron oxide powder, and nickel; magnetic particles are used as a core material, and the surface is a styrene resin or vinyl resin. Resin-coated carrier formed by coating a resin, ethylene-based resin, rosin-based resin, polyester-based resin, melamine-based resin or the like, or a wax such as stearic acid, and forming a resin coating layer; magnetic particles in the binder resin And a magnetic material-dispersed carrier in which is dispersed. Among them, the resin-coated carrier is particularly preferable because the chargeability of the toner and the resistance of the entire carrier can be controlled by the configuration of the resin coating layer.
The mixing ratio of the toner of the present invention and the carrier in the two-component electrostatic image developer is usually preferably 2 to 10 parts by weight of the toner with respect to 100 parts by weight of the carrier. Moreover, the preparation method of a developing agent is not specifically limited, For example, the method of mixing with a V blender etc. is mentioned.

(Image forming method)
The image forming method of the present invention includes a latent image forming step of forming an electrostatic latent image on the surface of the latent image holding member, and developing the electrostatic latent image formed on the surface of the latent image holding member with a developer containing toner. A developing step for forming a toner image, a transfer step for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and a fixing for thermally fixing the toner image transferred to the surface of the transfer target. An electrostatic charge image developing toner of the present invention as the toner, or the electrostatic charge image developer of the present invention as the developer.
In the image forming method of the present invention, a developer is prepared using the specific toner as described above, and an electrostatic image is formed and developed with a conventional electrophotographic copying machine using the developer. The image is electrostatically transferred onto the transfer paper, and is fixed by a heating roller fixing device in which the temperature of the upper heating roller is set to a constant temperature to form a copy image.
The image forming method of the present invention is particularly preferably used when performing high-speed fixing such that the contact time between the toner on the transfer paper and the heating roller is within 1 second, particularly within 0.5 seconds.

Further, the electrostatic image developer (electrostatic image developing toner) of the present invention can be used in an image forming method of a normal electrostatic image developing system (electrophotographic system). Specifically, the image forming method of the present invention includes, for example, an electrostatic latent image forming step, a toner image forming step, a transfer step, and a cleaning step. Each of the above steps is a general step per se, and is described in, for example, JP-A-56-40868 and JP-A-49-91231. The image forming method of the present invention can be carried out using an image forming apparatus such as a copier or a facsimile machine known per se.
The electrostatic latent image forming step is a step of forming an electrostatic latent image (electrostatic charge image) on the electrostatic latent image carrier. The toner image forming step is a step of developing the electrostatic latent image with a developer layer on a developer carrier to form a toner image. The developer layer is not particularly limited as long as it contains the electrostatic image developer of the present invention containing the electrostatic image developing toner of the present invention. The transfer step is a step of transferring the toner image onto a transfer body. The cleaning step is a step of removing the electrostatic charge image developer remaining on the electrostatic latent image carrier.
In the image forming method of the present invention, an embodiment that further includes a recycling step is preferable. The recycling step is a step of transferring the electrostatic image developing toner collected in the cleaning step to the developer layer. The image forming method including the recycling step can be performed using an image forming apparatus such as a toner recycling system type copying machine or facsimile machine. The present invention can also be applied to a recycling system in which the cleaning process is omitted and toner is collected simultaneously with development.

The maximum pressure during image fixing in the image forming method of the present invention is preferably 1 to 10 MPa.
If the maximum pressure during fixing is 1 MPa or more, sufficient thick paper fixing properties can be obtained, and if it is 10 MPa or less, the hot offset temperature is good, the image is stained, the fixing roll is contaminated, and the paper is wound. It is preferable because it is difficult to curl and paper curl is unlikely to occur. The paper curl is a state where the paper after fixing is greatly bent.

As the recording medium that can be used in the image forming method of the present invention, for example, plain paper, cardboard, OHP sheet, coated paper whose surface is coated with resin, art paper for printing, etc. are preferably used. can do. Further, as the recording medium, it is preferable to use cardboard because the effects of the present invention can be remarkably exhibited.
In addition, a thick paper means the paper which is 90 g / m < ² > or more.
The image forming method of the present invention is a particularly excellent method for forming an image on cardboard, and is preferable because high-speed fixing using cardboard can reduce fixing energy while achieving both high image quality and reliability.
In addition to excellent image formation on cardboard, the present invention shows effective performance without problems for plain paper weighing less than 90 g / m ² , reducing fixing energy, or at the same energy. The image forming speed per hour can be improved.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all.
In the following description, “parts” means “parts by weight” unless otherwise specified.

For the measurement of the molecular weight, the weight average molecular weight Mw and the number average molecular weight Mn were measured by gel permeation chromatography (GPC) under the conditions described below. At a temperature of 40 ° C., a solvent (tetrahydrofuran) is flowed at a flow rate of 1.2 ml per minute, and 3 mg of a tetrahydrofuran sample solution having a concentration of 0.2 g / 20 ml is injected as a sample weight for measurement. When measuring the molecular weight of a sample, select the measurement conditions that fall within the range in which the logarithm of the molecular weight of the prepared calibration curve and the count number are linear, using several monodisperse polystyrene standard samples. .
In addition, the reliability of the measurement results is that the NBS706 polystyrene standard sample performed under the above measurement conditions is
Weight average molecular weight Mw = 28.8 × 10 ⁴
Number average molecular weight Mn = 13.7 × 10 ⁴
Can be confirmed.
Further, as the GPC column, TSK-GEL, GMH (manufactured by Tosoh Corporation), etc. satisfying the above conditions were used.
The median diameter was measured with a laser diffraction particle size distribution analyzer (LA-920, manufactured by Horiba, Ltd.) or Coulter Multisizer II (manufactured by Beckman-Coulter).
The glass transition point and melting point of the resin were measured using a differential scanning calorimeter (DSC-50) manufactured by Shimadzu Corporation.

<Preparation of resin particle dispersion (A1) (styrene-butyl acrylate type, acidic polar group type)>
In a round glass flask, 300 parts by weight of ion-exchanged water and 1.5 parts by weight of TTAB (tetradecyltrimethylammonium bromide, manufactured by Sigma) were placed, nitrogen bubbling was performed for 20 minutes, and 65 ° C. with stirring. The temperature was raised to. 40 parts by weight of n-butyl acrylate monomer was added, and the mixture was further stirred for 20 minutes. After dissolving 0.5 parts by weight of initiator V-50 (2,2′-azobis (2-methylpropionamidine) dihydrochloride, manufactured by Wako Pure Chemical Industries, Ltd.) in 10 parts by weight of ion-exchanged water, Charged into flask. The mixture was held at 65 ° C. for 3 hours, and 60 parts by weight of styrene monomer, 10 parts by weight of n-butyl acrylate monomer, 2 parts by weight of acrylic acid and 0.8 part by weight of dodecanethiol were dissolved in 0.5 part by weight of TTAB. The emulsified liquid emulsified in 100 parts by weight of ion-exchanged water was continuously charged into the flask using a metering pump over 2 hours. The temperature was raised to 70 ° C. and held for another 2 hours to complete the polymerization. A core-shell type resin particle dispersion (A1) having a weight average molecular weight Mw of 25,000, an average particle diameter of 150 nm, and a solid content of 25% by weight was obtained.
After the resin was air-dried at 40 ° C., Tg behavior was analyzed from −150 ° C. with a differential scanning calorimeter (DSC) manufactured by Shimadzu Corporation, and a glass transition due to polybutyl acrylate was observed around −50 ° C. A glass transition due to a copolymer considered to be composed of a styrene-butyl acrylate-acrylic acid copolymer was observed in the vicinity of 0 ° C. (glass transition temperature difference: 110 ° C.).

<Preparation of resin particle dispersion (A2) (styrene-2-ethylhexyl acrylate (EHA) system, basic polar group system)>
In a round glass flask, 300 parts by weight of ion-exchanged water and 1.5 parts by weight of TTAB (tetradecyltrimethylammonium bromide, manufactured by Sigma) were placed, nitrogen bubbling was performed for 20 minutes, and 65 ° C. with stirring. The temperature was raised to. 40 parts by weight of 2-ethylhexyl acrylate monomer was added, and the mixture was further stirred for 20 minutes. After dissolving 0.5 parts by weight of initiator V-50 (2,2′-azobis (2-methylpropionamidine) dihydrochloride, manufactured by Wako Pure Chemical Industries, Ltd.) in 10 parts by weight of ion-exchanged water, Charged into flask. Holding at 65 ° C. for 3 hours, 60 parts by weight of styrene monomer, 10 parts by weight of n-butyl acrylate monomer, 1.2 parts by weight of diethylaminoethyl acrylate and 0.5 part by weight of dodecanethiol The emulsified liquid emulsified in 100 parts by weight of ion-exchanged water in which TTAB was dissolved was continuously charged into the flask using a metering pump over 2 hours. The temperature was raised to 70 ° C. and held for another 2 hours to complete the polymerization. A core-shell resin particle dispersion (A2) having a weight average molecular weight Mw of 25,000, an average particle diameter of 130 nm, and a solid content of 25% by weight was obtained.
After the resin was air-dried at 40 ° C., when Tg behavior was analyzed from −150 ° C. with a differential scanning calorimeter (DSC) manufactured by Shimadzu Corporation, a glass transition due to poly (2-ethylhexyl acrylate) was observed around −65 ° C. Moreover, the glass transition by the copolymer considered to consist of a styrene-butyl acrylate-acrylic acid copolymer was observed in the vicinity of 60 ° C. (glass transition temperature difference: 125 ° C.).

<Preparation of resin particle dispersion (A3) (styrene-butyl methacrylate (nBMA) type, alcohol type hydroxyl group type)>
In a round glass flask, 300 parts by weight of ion-exchanged water and 1.5 parts by weight of TTAB (tetradecyltrimethylammonium bromide, manufactured by Sigma) were placed, nitrogen bubbling was performed for 20 minutes, and 65 ° C. with stirring. The temperature was raised to. 40 parts by weight of n-butyl methacrylate monomer was added, and the mixture was further stirred for 20 minutes. After dissolving 0.5 parts by weight of initiator V-50 (2,2′-azobis (2-methylpropionamidine) dihydrochloride, manufactured by Wako Pure Chemical Industries, Ltd.) in 10 parts by weight of ion-exchanged water, Charged into flask. Holding at 65 ° C. for 3 hours, 0.5 part by weight of 60 parts by weight of styrene monomer, 15 parts by weight of n-butyl acrylate monomer, 2 parts by weight of 2-hydroxyethyl methacrylate and 0.8 part by weight of dodecanethiol The emulsified liquid emulsified in 100 parts by weight of ion-exchanged water dissolved in was continuously charged into the flask using a metering pump over 2 hours. The temperature was raised to 70 ° C. and held for another 2 hours to complete the polymerization. A core-shell type resin particle dispersion (A3) having a weight average molecular weight Mw of 25,000, an average particle diameter of 260 nm, and a solid content of 25% by weight was obtained.
After the resin was air-dried at 40 ° C., when Tg behavior was analyzed from −150 ° C. with a differential scanning calorimeter (DSC) manufactured by Shimadzu Corporation, a glass transition due to polybutyl methacrylate was observed around 25 ° C., and around 50 ° C. The glass transition by the copolymer considered to consist of a styrene-butyl acrylate-acrylic acid copolymer was observed (glass transition temperature difference: 25 degreeC).

<Preparation of resin particle dispersion (A4) (conventional styrene-butyl acrylate (BA) type, acidic polar group type)>
Styrene 460 parts by weight n-butyl acrylate 140 parts by weight Acrylic acid 12 parts by weight Dodecanethiol 9 parts by weight The above components were mixed and dissolved to prepare a solution.
On the other hand, 12 parts by weight of an anionic surfactant (manufactured by Dow Chemical Co., Dowfax) was dissolved in 250 parts by weight of ion-exchanged water, and the above solution was added and dispersed and emulsified in a flask (monomer emulsion A). .
Furthermore, 1 part by weight of an anionic surfactant (manufactured by Dow Chemical Co., Dowfax) was dissolved in 555 parts by weight of ion-exchanged water and charged into a polymerization flask.
The polymerization flask was sealed, a reflux tube was installed, and the polymerization flask was heated to 75 ° C. with a water bath while being slowly stirred while injecting nitrogen, and held.
9 parts by weight of ammonium persulfate was dissolved in 43 parts by weight of ion-exchanged water and dropped into the polymerization flask via a metering pump over 20 minutes, and then the monomer emulsion A was added for 200 minutes through the metering pump. It was dripped over.
Thereafter, the polymerization flask was kept at 75 ° C. for 3 hours while continuing the stirring slowly to complete the polymerization.
As a result, an amorphous resin particle dispersion (A4) having a particle central diameter of 210 nm, a glass transition point of 53.5 ° C., a weight average molecular weight of 31,000, and a solid content of 42% was obtained.

<Production of Resin Particle Dispersion (A5) (Styrene-Butyl Methacrylate (nBMA) System, Alcohol Based Hydroxyl System)>
In a round glass flask, 300 parts by weight of ion-exchanged water and 1.5 parts by weight of TTAB (tetradecyltrimethylammonium bromide, manufactured by Sigma) were placed, nitrogen bubbling was performed for 20 minutes, and 65 ° C. with stirring. The temperature was raised to. 40 parts by weight of n-butyl methacrylate monomer was added, and the mixture was further stirred for 20 minutes. After dissolving 0.5 parts by weight of initiator V-50 (2,2′-azobis (2-methylpropionamidine) dihydrochloride, manufactured by Wako Pure Chemical Industries, Ltd.) in 10 parts by weight of ion-exchanged water, Charged into flask. Holding at 65 ° C. for 3 hours, 0.5 part by weight of 50 parts by weight of styrene monomer, 25 parts by weight of n-butyl acrylate monomer, 2 parts by weight of 2-hydroxyethyl methacrylate and 0.8 part by weight of dodecanethiol The emulsified liquid emulsified in 100 parts by weight of ion-exchanged water dissolved in was continuously charged into the flask using a metering pump over 2 hours. The temperature was raised to 70 ° C. and held for another 2 hours to complete the polymerization. A core-shell resin particle dispersion (A5) having a weight average molecular weight Mw of 25,000, an average particle diameter of 280 nm, and a solid content of 25% by weight was obtained.
After the resin was air-dried at 40 ° C., when Tg behavior was analyzed from −150 ° C. with a differential scanning calorimeter (DSC) manufactured by Shimadzu Corporation, a glass transition due to polybutyl methacrylate was observed around 25 ° C., and around 42 ° C. The glass transition by the copolymer considered to consist of a styrene-butyl acrylate-acrylic acid copolymer was observed (glass transition temperature difference: 17 degreeC).

<Preparation of resin particle dispersion (A6) (methyl methacrylate-butyl acrylate system, acidic polar group system)>
In a round glass flask, 300 parts by weight of ion-exchanged water and 1.5 parts by weight of TTAB (tetradecyltrimethylammonium bromide, manufactured by Sigma) were placed, nitrogen bubbling was performed for 20 minutes, and 65 ° C. with stirring. The temperature was raised to. 40 parts by weight of n-butyl acrylate monomer was added, and the mixture was further stirred for 20 minutes. After dissolving 0.5 parts by weight of initiator V-50 (2,2′-azobis (2-methylpropionamidine) dihydrochloride, manufactured by Wako Pure Chemical Industries, Ltd.) in 10 parts by weight of ion-exchanged water, Charged into flask. Hold at 65 ° C. for 3 hours, dissolve 60 parts by weight of methyl methacrylate monomer, 10 parts by weight of n-butyl acrylate monomer, 2 parts by weight of acrylic acid and 0.8 part by weight of dodecanethiol to dissolve 0.5 part by weight of TTAB. The emulsified liquid emulsified in 100 parts by weight of ion-exchanged water was continuously charged into the flask using a metering pump over 2 hours. The temperature was raised to 70 ° C. and held for another 2 hours to complete the polymerization. A core-shell type resin particle dispersion (A6) having a weight average molecular weight Mw of 25,000, an average particle diameter of 110 nm, and a solid content of 25% by weight was obtained.
After the resin was air-dried at 40 ° C., when Tg behavior was analyzed from −150 ° C. with a differential scanning calorimeter (DSC) manufactured by Shimadzu Corporation, a glass transition due to polybutyl acrylate was observed around −50 ° C., A glass transition due to a copolymer considered to be composed of a methyl methacrylate -butyl acrylate-acrylic acid copolymer was observed around 55 ° C. (glass transition temperature difference: 105 ° C.).

<Preparation of Colorant Particle Dispersion (1)>
Cyan pigment (manufactured by Dainichi Seika Co., Ltd., copper phthalocyanine CI Pigment Blue 15: 3) 50 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) 5 parts by weight Deionized water 200 parts by weight Part The above components were mixed and dissolved, and dispersed for 5 minutes with a homogenizer (IKA, Ultra Tarrax) for 10 minutes using an ultrasonic bath, and a cyan colorant particle dispersion (P1) having a center diameter of 190 nm and a solid content of 21.5% Got.

<Preparation of Colorant Particle Dispersion (2)>
In the preparation of the colorant particle dispersion liquid (1), the colorant particle dispersion liquid (1) and the magenta pigment (Daiichi Ink Chemical Co., Ltd., CI Pigment Red 122) were used instead of the cyan pigment. In the same manner, a magenta colorant particle dispersion (P2) having a center diameter of 165 nm and a solid content of 21.5% was obtained.

<Preparation of release agent particle dispersion (1)>
30 parts by weight of dodecyl sulfate and 852 parts by weight of ion-exchanged water were mixed to prepare a dodecyl sulfate aqueous solution.
188 parts by weight of palmitic acid 25 parts by weight of pentaerythritol were mixed, heated to 250 ° C. and melted, then poured into the above-mentioned aqueous dodecyl sulfate solution, emulsified with a homogenizer (IKA, Ultra Tarrax) for 5 minutes, and further After emulsification in an ultrasonic bath for 15 minutes, the emulsion was maintained at 70 ° C. in a flask while stirring and held for 15 hours.
As a result, a release agent particle dispersion (W1) having a particle center diameter of 200 nm, a melting point of 72 ° C., and a solid content of 20% was obtained.

<Preparation of release agent particle dispersion (2)>
Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) 2 parts by weight Ion-exchanged water 800 parts by weight Carnauba wax 200 parts by weight were mixed, heated to 100 ° C and melted, and then homogenizer (manufactured by IKA) Then, the mixture was emulsified for 15 minutes, and further emulsified at 100 ° C. using a gorin homogenizer.
Thus, a release agent fine particle dispersion (W2) having a particle central diameter of 170 nm, a melting point of 83 ° C., and a solid content of 20% was obtained.

(Toner Example 1)
<Preparation of toner particles>
Resin particle dispersion (A1) 168 parts by weight (resin 42 parts by weight)
Colorant particle dispersion (P1) 40 parts by weight (8.6 parts by weight of pigment)
Release agent particle dispersion (W1) 40 parts by weight (release agent 8.6 parts by weight)
-0.15 parts by weight of polyaluminum chloride-300 parts by weight of ion-exchanged water In accordance with the above formulation, the above components were thoroughly mixed and dispersed in a round stainless steel flask with a homogenizer (IKA, Ultra Turrax T50). The flask was heated to 42 ° C. while stirring the flask in a heating oil bath, and maintained at 42 ° C. for 60 minutes, and then 84 parts by weight (21 parts by weight of the resin particle dispersion (1)) was added and gently stirred.
Thereafter, the pH in the system was adjusted to 6.0 with a 0.5 mol / liter aqueous sodium hydroxide solution, and then heated to 95 ° C. while stirring was continued. During the period up to 95 ° C., an aqueous sodium hydroxide solution was added dropwise so that the pH did not become 5.0 or less. Hold at 95 ° C. for 3 hours.
After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then solid-liquid separated by Nutsche suction filtration. Then, it was redispersed in 3 liters of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This washing operation was repeated 5 times, followed by solid-liquid separation by Nutsche suction filtration, and then vacuum drying for 12 hours to obtain toner particles.
When the particle size of the toner particles was measured with a Coulter counter, the cumulative volume average particle size D ₅₀ was 4.7 μm, and the volume average particle size distribution index GSDv was 1.21. The shape factor SF1 of the toner particles determined from the shape observation with Luzex was 130 potato shapes.
To 50 parts by weight of the toner particles, 1.5 parts by weight of hydrophobic silica (manufactured by Cabot, TS720) was added and mixed by a sample mill to obtain an externally added toner.
Then, using a ferrite carrier having an average particle diameter of 50 μm coated with 1% of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd.), the above externally added toner was weighed so that the toner concentration would be 5%, A developer was prepared by stirring and mixing for a minute.

<Evaluation of toner>
In the modified machine of Docu Center Color f450 manufactured by Fuji Xerox Co., Ltd.
The two-roll type fixing machine was modified so that the maximum fixing pressure was 1.2 MPa (12 kgf / cm ² ) (Furthermore, the heating roll was changed to a high-hardness roll coated with Teflon (registered trademark) on a SUS tube). 9.8MPa), and the transfer paper is mirror coated platinum paper (256g / m ² ), a thick coated paper specified by Fuji Xerox Co., Ltd., and the process speed is adjusted to 180mm / sec. As a result, the oil-less fixability is good, and the minimum fixing temperature (this temperature is determined by image contamination by cloth rubbing of the image) is 120 ° C. or higher, and the image has sufficient fixability. The gloss uniformity was also good. Both developability and transferability were good, and there was no image defect and a high quality and good image (◯) was shown. Even at a fixing temperature of 180 ° C., no occurrence of hot offset was observed. In addition, the above-mentioned modified machine was subjected to a continuous print test of 50,000 sheets at 23 ° C. and 55% RH, but the initial good image quality was maintained until the end (continuous test maintainability: ◯).

The toner (developer) was evaluated according to the following criteria.
a. Oil-less fixability A case where the roll does not wrap even if no oil is applied to the heated roll is considered good.
b. Minimum fixing temperature (thick paper fixability)
The minimum fixing temperature was the lowest temperature of the heating roller at which the fixed image was folded and opened, and then the folded fixed image surface was rubbed with a gauze cloth so that no defect in the fixed image occurred.
c. Gloss Uniformity A solid (surface) image in one sheet was visually observed. A case where no difference in gloss was visually observed in the paper was considered good.
d. Image quality The image quality was determined as follows by measuring the fine line reproducibility of the image with the fine line fixed and the fog (visual observation) of the non-fixed part with a loupe.
○ ... There is no unevenness in fine lines and there is no fogging. △ ... There is slight unevenness in image quality. × ... There is unevenness in image quality. Hot offset generation temperature The offset generation temperature is measured by performing the fixing process with the above-described copying machine, and then sending a blank transfer paper to the fixing unit under the same conditions, and visually confirming whether toner contamination occurs. The observation operation was repeated while changing the set temperature of the fixing device, and the lowest set temperature at which the toner was smeared was determined as the offset generation temperature.
f. Continuous test maintainability A continuous image output test of 50,000 sheets was performed under the condition of 23 ° C. and 55% RH, and the following determination was made.
○ ・ ・ ・ The initial good image quality was maintained until the end ○ ^-・ ・ ・ The initial good image quality was slightly degraded, but it was in a practically acceptable range △ ・ ・ ・ Slight image quality degradation × ・ ・ ・ Clear image quality degradation occurred

(Toner Example 2)
Using the resin particle dispersion (A2), the release agent particle dispersion (W1), and the colorant particle dispersion (P2), replacing the polyaluminum chloride with aluminum sulfate, the pH when raising the temperature to 95 ° C. is 7. A toner was prepared and evaluated in the same manner as in Toner Example 1 except that the value was 0. The minimum fixing temperature was 115 ° C. or higher and sufficient fixing properties were exhibited.
Even in the continuous test maintainability, the initial good image quality was maintained until the end (continuous test maintainability: ◯).

(Toner Example 3)
A toner was prepared in the same manner as in Toner Example 1, using the resin particle dispersion (A3), the release agent particle dispersion (W2), and the colorant particle dispersion (P2). The minimum fixing temperature was 105 ° C. or more and sufficient fixing properties were exhibited.

<Evaluation of toner>
In the modified Docu Center Color f450 manufactured by Fuji Xerox Co., Ltd., using the developer described above, Teflon (registered trademark) is applied to the SUS tube so that the maximum fixing pressure is 9.5 MPa (12 kgf / cm ² ). The two-roll type fixing machine was modified by changing to a coated high hardness roll.
Mirror-coated platinum paper (256 g / m ² ), a thick coated paper specified by Fuji Xerox Co., was used as the transfer paper, and when the toner fixing property was examined by adjusting the process speed to 180 mm / sec, oilless fixing property was obtained. The minimum fixing temperature (this temperature is judged by image contamination by cloth rubbing of the image) is 105 ° C. or higher, and the image exhibits sufficient fixability and gloss uniformity. It was. Both developability and transferability were good, and there was no image defect and a high quality and good image (◯) was shown. Even at a fixing temperature of 180 ° C., no occurrence of hot offset was observed. In addition, the above-mentioned modified machine was subjected to a continuous print test of 50,000 sheets at 23 ° C. and 55% RH, and although there was some deterioration from the initial good image quality, it was in a range where there was no practical problem (continuous). Test maintenance: ○ ^- ).

(Toner Example 4)
A toner was prepared in the same manner as in Toner Example 1 except that the resin particle dispersion (A1) in Example 1 was a 1: 1 mixture of the resin particle dispersion (A1) and the resin particle dispersion (A4). . The minimum fixing temperature was 125 ° C. or higher and sufficient fixing properties were exhibited.
Even in the continuous test maintainability, the initial good image quality was maintained until the end (continuous test maintainability: ◯).

(Toner Comparative Example 1)
A toner was prepared in the same manner as in Toner Example 1 except that the resin particle dispersion (A5) was used. The minimum fixing temperature was 140 ° C. and sufficient fixing properties were exhibited. Hot offset was observed at 170 ° C. Slight image unevenness was observed in the initial image quality (image evaluation: Δ). In the continuous test, toner filming occurred on the photoconductor at around 10,000 sheets, and streak defects were observed (continuous test maintainability: x).

(Toner Comparative Example 2)
A toner was prepared in the same manner as in Toner Example 1 except that the resin particle dispersion (A4) was used. The minimum fixing temperature was 145 ° C. and sufficient fixing properties were exhibited. Hot offset was observed at 180 ° C. Even in the continuous test maintainability, the initial good image quality was maintained until the end (continuous test maintainability: ◯).

(Toner Example 5)
A toner was prepared in the same manner as in Toner Example 1 except that the resin particle dispersion (A6) was used. The minimum fixing temperature was 105 ° C. and sufficient fixing properties were exhibited. Hot offset was not observed even at 180 ° C. Even in the continuous test maintainability, the initial good image quality was maintained until the end (continuous test maintainability: ◯).

Claims (5)

An electrostatic image developing toner obtained by aggregating resin particles having a core-shell structure,
Both the resin constituting the core and the shell are non-crystalline resins,
The glass transition point of the resin constituting the core and the glass transition point of the resin constituting the shell are different by 20 ° C. or more,
The resin constituting the shell contains an acidic or basic polar group, or an alcoholic hydroxyl group,
The resin constituting the core and the shell is a homopolymer or copolymer of an ethylenically unsaturated monomer,
The resin constituting the shell is a copolymer of styrene, n-butyl acrylate and a monomer having a polar group, or a copolymer of methyl methacrylate, n-butyl acrylate and a monomer having a polar group. Yes,
The monomer having the polar group is a monomer selected from the group consisting of acrylic acid, diethylaminoethyl acrylate, and 2-hydroxyethyl methacrylate;
The resin constituting the core is poly (n-butyl acrylate) or poly (2-ethylhexyl acrylate),
The glass transition point of the resin that constitutes the shell is higher than the resin that constitutes the core,
The glass transition point of the resin constituting the shell is 45 to 80 ° C.,
An electrostatic charge image developing toner characterized by exhibiting pressure plasticization. The resin constituting the shell is a copolymer of a monomer having a styrene and n- butyl acrylate and a polar group, and to claim 1 which is 80 wt% or more of styrene emissions or we constructed tree butter The toner for developing an electrostatic image according to the description. Dispersing at least the resin particles having the core-shell structure and the release agent particles in an aqueous medium;
Aggregating dispersed particles to obtain agglomerated particles; and
The method for producing a toner for developing an electrostatic charge image according to claim 1, comprising a step of fusing the aggregated particles by heating.   An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1 or 2 or the electrostatic charge image developing toner produced by the production method according to claim 3 and a carrier. A latent image forming step for forming an electrostatic latent image on the surface of the latent image holding member;
A developing step of forming a toner image by developing the electrostatic latent image formed on the surface of the latent image holding member with a developer containing toner;
A transfer step of transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target; and
An image forming method comprising a fixing step of thermally fixing the toner image transferred to the surface of the transfer material,
The electrostatic image developing toner according to claim 1 or 2 as the toner, the electrostatic image developing toner produced by the production method according to claim 3, or the electrostatic image according to claim 4 as the developer. An image forming method using a charge image developer.