JP2012042523A - Toner for electrostatic charge image development, developer for electrostatic charge image development, method of manufacturing toner for electrostatic charge image development, and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development, a developer for electrostatic charge image development, a method of manufacturing the toner for electrostatic charge image development, and an image formation apparatus which are able to improve charging environmental stability and colorant dispersibility.SOLUTION: The toner for electrostatic charge image development at least contains a binder resin, a colorant, a release agent, and a cresol sulfonic acid formalin condensate represented by following general formula (1). The cresol sulfonic acid formalin condensate can improve dispersibility of colorant particles.

Description

  The present invention relates to an electrostatic image developing toner, an electrostatic image developing developer, a method for producing an electrostatic image developing toner, and an image forming apparatus.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic charge image is formed on a photoreceptor by charging and exposure processes, and the electrostatic charge image is developed with a developer containing an electrostatic charge image developing toner (hereinafter sometimes referred to simply as “toner”). Then, the electrostatic image is visualized through the transfer and fixing processes.

  As a method for producing the toner, for example, there is an emulsion polymerization aggregation method, and toner fine particles are produced from a mixed dispersion in which a binder resin, a colorant, and the like are dispersed through an aggregation step and the like. At this time, various surfactants have been used for the purpose of improving the dispersion stability of the mixed dispersion. For example, the following Patent Document 1 discloses a method for producing an electrostatic charge image developing toner comprising a particle aggregate containing at least polymer primary particles, wherein a formalin polycondensate of naphthalene sulfonate is added. A method for producing a toner for image development is disclosed, and a formalin polycondensate of naphthalene sulfonate is added after adding a metal salt which is an aggregating agent for aggregating primary polymer particles and colorant particles in a colored particle forming step. It is added to suppress the viscosity increase of the mixed solution.

  Formalin polycondensate of naphthalene sulfonate includes formalin polycondensate of sodium creosote oil sulfonate, formalin polycondensate of sodium cresol sulfonate and sodium 2-naphthol-6-sulfonate, and formalin polycondensation of sodium cresol sulfonate. Products, a formalin polycondensate of sodium phenolsulfonate, a formalin polycondensate of sodium β-naphtholsulfonate, a formalin polycondensate of sodium β-naphthalenesulfonate, and the like.

  Patent Document 2 listed below is a toner containing at least core particles formed by aggregating resin particles, colorant particles and wax particles, and a polymer in a colorant particle dispersion in which the colorant particles are dispersed. A toner comprising a system dispersant and an anionic dispersant is disclosed.

  Further, in Patent Document 3 below, in a toner produced from at least a binder resin and a color component in an aqueous medium, 50 to 100% by weight of the binder resin is a polyester resin, and the color component is a colorant. An image forming toner, an electrostatic latent image developer, and a method for producing the same are disclosed, which contain a basic polymer copolymer dispersant and a pigment derivative.

JP 2008-209460 A JP 2009-151056 A JP 2005-181835 A

  An object of the present invention is to provide an electrostatic image developing toner capable of improving the environmental stability of charging and the dispersibility of a colorant, a developer for developing an electrostatic image, a method for producing an electrostatic image developing toner, and image formation. To provide an apparatus.

  In order to achieve the above object, the invention for an electrostatic charge image developing toner according to claim 1 comprises at least a binder resin, a colorant, a release agent and a cresolsulfonic acid formalin condensation represented by the following general formula (1): It contains a product.

  An electrostatic charge image developing developer according to a second aspect includes the electrostatic charge image developing toner according to the first aspect and a carrier.

  An invention of a method for producing a toner for developing an electrostatic charge image according to claim 3 comprises: a mixing step of mixing a dispersion of binder resin particles having a volume average particle size of 1 μm or less and a dispersion of colorant particles; An aggregating step for aggregating the binder resin particles and the colorant particles by adding an agent; and after the aggregating step, the aggregated particles are combined at a temperature equal to or higher than the melting point of the binder resin, which is a main component of the binder resin particles. A cresol sulfonic acid formalin condensate is contained in the dispersion of the colorant particles.

  An image forming apparatus according to a fourth aspect of the present invention includes an image carrier, a latent image forming unit that forms an electrostatic latent image on a surface of the image carrier, and the developer for developing an electrostatic charge image according to claim 2. Developing means for developing the electrostatic latent image to form a toner image, transfer means for transferring the toner image formed on the image holding member onto the transfer target, and transfer onto the transfer target. And fixing means for fixing the toner image.

  According to the invention of claim 1, the dispersibility of the colorant can be improved by the cresolsulfonic acid formalin condensate.

  According to the second aspect of the present invention, it is possible to provide a developer for developing an electrostatic image capable of forming an image with improved fog and image density.

  According to the invention of claim 3, it is possible to produce a toner for developing an electrostatic image with improved dispersibility of the colorant.

  According to the invention of claim 4, an image forming apparatus capable of forming an image with improved fog and image density can be provided.

1 is a schematic view of an example of an image forming apparatus according to an embodiment.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described.

<Toner for electrostatic image development>
The toner for developing an electrostatic charge image according to the present embodiment (hereinafter sometimes simply referred to as “toner”) contains at least a binder resin, a colorant, a release agent, and a cresolsulfonic acid formalin condensate. To do.

  The cresol sulfonic acid formalin condensate can be used to disperse a binder resin, a colorant, a release agent and the like in water and other solutions. In the present embodiment, it is used at least for dispersing the colorant. This cresol sulfonic acid formalin condensate is represented by the following general formula (1).

  In general, in order to improve the dispersibility of the colorant inside the toner, it is necessary to add a large amount of a surfactant in the colorant dispersion or in the aggregation step. However, when the addition amount of the surfactant is increased, the environmental stability of charging of the toner is decreased (the charging property of the toner is decreased due to an increase in environmental humidity). When carbon black is used as the colorant, if the dispersibility is lowered, a conductive path is formed in the toner, and the electrical characteristics (chargeability) are greatly deteriorated. For this reason, a surfactant that exhibits high dispersibility when added in a small amount is desirable, but this requirement can be satisfied by using the cresolsulfonic acid formalin condensate.

<Toner production method>
Hereinafter, a method for producing a toner for developing an electrostatic image according to the embodiment will be described. Although there is no restriction | limiting in particular as this manufacturing method, The emulsion aggregation method is preferable. The emulsion aggregation method includes a mixing step of mixing a dispersion of binder resin particles having a volume average particle size of 1 μm or less and a dispersion of colorant particles, and adding the flocculant to the binder resin particles and the colorant. An aggregation step of aggregating the particles, and a coalescence step of coalescing the aggregated particles at a temperature equal to or higher than the melting point of the binder resin that is the main component of the binder resin particles after the aggregation step, The dispersion of the colorant particles contains a cresol sulfonic acid formalin condensate represented by the general formula (1).

  In the aggregating step, after forming aggregated particles (core aggregated particles), a second resin fine particle dispersion in which fine particles of the second binder resin are dispersed is added, and the second aggregated particles are formed on the surface of the core aggregated particles. It is also preferable to form a toner having a core-shell structure by forming resin-attached aggregated particles to which fine particles of the binder resin are attached.

-Binder resin-
As the binder resin, a styrene-acrylic resin (a copolymer of styrene and an acrylate ester), a polyester resin, or the like can be used.

  Examples of the acrylic acid ester used for the styrene-acrylic resin include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like. The polymerization of the styrene-acrylic resin is preferably emulsion polymerization using diphenyl oxide disulfonate or a surfactant represented by the above general formula (1) as an emulsifier. As a polymerization initiator in this case, for example, ammonium persulfate can be used.

  The weight average molecular weight Mw of the styrene-acrylic resin is preferably 6000 to 40,000. If the weight average molecular weight Mw is less than 6000, the toner may permeate the surface of a recording medium such as paper at the time of fixing to cause uneven fixing, or the strength against bending resistance of a fixed image may be reduced. On the other hand, when the weight average molecular weight Mw exceeds 40,000, the viscosity at the time of melting becomes too high, the temperature for reaching a viscosity suitable for fixing may be increased, and as a result, the low-temperature fixability may be impaired.

  The glass transition temperature (Tg) of the styrene-acrylic resin is preferably in the range of 40 to 80 ° C. When Tg is lower than 40 ° C., toner storage stability and fixed image storage stability may be deteriorated. If it is higher than 80 ° C., it may not be fixed at a lower temperature than in the past.

  On the other hand, as the polymerizable monomer component constituting the polyester resin, a polymerizable monomer having an aromatic component or a polymerizable monomer having a linear aliphatic component can be used. Furthermore, it is desirable that the component derived from the polymerizable monomer is 30 mol% or more for each single species in the polymer. In the polyester resin, two or more polymerizable monomers are essential as a constituent component, but it is desirable that each essential constituent polymerizable monomer species have the same configuration (30 mol% or more).

  The polyester resin is synthesized from, for example, a polyvalent carboxylic acid component and a polyhydric alcohol component. In the present embodiment, a commercially available product may be used as the polyester resin, or a synthesized product may be used.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12 -Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid Aromatic dicarboxylic acids such as dibasic acids and the like, and the anhydrides and lower alkyl esters thereof are also included, but not limited thereto.

  Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And the lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  Moreover, as a polyvalent carboxylic acid component, the dicarboxylic acid component which has a sulfonic acid group other than the said aliphatic dicarboxylic acid and aromatic dicarboxylic acid may be contained.

  Furthermore, as a polyvalent carboxylic acid component, you may contain the dicarboxylic acid component which has a double bond other than the said aliphatic dicarboxylic acid and aromatic dicarboxylic acid.

  The polyhydric alcohol component is preferably an aliphatic diol, more preferably a linear aliphatic diol having a main chain portion having 7 to 20 carbon atoms. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting temperature may be lowered. Further, when the main chain portion has less than 7 carbon atoms, when polycondensation with an aromatic dicarboxylic acid, the melting temperature becomes high and fixing at low temperature may be difficult, while the main chain portion has 20 carbon atoms. Exceeding the above range makes it difficult to obtain practical materials. The number of carbon atoms in the main chain portion is more preferably 14 or less.

  Specific examples of the aliphatic diol suitably used for the synthesis of the polyester resin include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tride Examples include, but are not limited to, candiol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like. Among these, considering availability, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are desirable.

  Trivalent or higher alcohols can also be used as the polyhydric alcohol component, and examples thereof include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used individually by 1 type and may use 2 or more types together.

  Among the polyhydric alcohol components, the content of the aliphatic diol is preferably 80 mol% or more, and more preferably 90 mol% or more. If the content of the aliphatic diol is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting temperature is lowered, so that the toner blocking resistance, the image storage stability and the low-temperature fixability may be deteriorated.

  If necessary, a polycarboxylic acid or a polyhydric alcohol may be added at the final stage of the synthesis for the purpose of adjusting the acid value or the hydroxyl value. Examples of polycarboxylic acids include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and other aromatic carboxylic acids, maleic anhydride, fumaric acid, succinic acid, alkenyl Examples thereof include aliphatic carboxylic acids such as succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid.

  There is no restriction | limiting in particular in the manufacturing method of the said polyester resin, It can manufacture with the general polyester polymerization method which makes a polyhydric carboxylic acid component and a polyhydric alcohol component react. For example, direct polycondensation, transesterification, and the like are used depending on the type of monomer. The molar ratio (acid component / alcohol component) for reacting the polyvalent carboxylic acid component with the polyhydric alcohol component is usually about 1/1, although it varies depending on the reaction conditions and the like. The polyester resin can be produced at a polymerization temperature of 180 to 230 ° C., and the reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during condensation.

  Examples of the catalyst used in the production of the polyester resin include alkali metal compounds such as sodium and lithium, alkaline earth metal compounds such as magnesium and calcium, zinc, manganese, antimony, titanium, tin, zirconium, and germanium. And metal compounds such as phosphorous compounds, phosphoric acid compounds, and amine compounds.

  The weight average molecular weight (Mw) of the polyester resin is desirably 6000 to 35000. If the weight average molecular weight (Mw) is less than 6000, the toner may permeate the surface of a recording medium such as paper during fixing and uneven fixing may occur, or the strength of the fixed image against bending resistance may decrease. is there. On the other hand, if the weight average molecular weight (Mw) exceeds 35000, the viscosity at the time of melting becomes too high, and the temperature for reaching a viscosity suitable for fixing may be increased, and as a result, the fixability may be impaired. .

-Colorant-
The colorant contained in the toner may be a dye or a pigment, but a pigment is desirable from the viewpoint of light resistance and water resistance.

  In the present embodiment, examples of the pigment used as the colorant include the following. Examples of yellow pigments include yellow lead, zinc yellow, yellow iron oxide, cadmium yellow, chrome yellow, Hansa yellow, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, selenium yellow, quinoline yellow, and permanent yellow NCG. Is mentioned. Specifically, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 180, C.I. I. Pigment Yellow 93 and the like, and C.I. I. Pigment Yellow 74 is preferable. As the yellow pigment, one or more of the above pigments can be used in combination.

  Examples of black pigments include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, and magnetite.

  Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, benzidine orange GG, indanthrene brilliant orange RK, indanthrene brilliant oren GK and the like.

  Examples of red pigments include bengara, cadmium red, red lead, mercury sulfide, quinacridone, watch young red, permanent red 4R, resol red, brilliantamine 3B, brilliantamine 6B, dapon oil red, pyrazolone red, rhodamine B lake, rake. Examples include Red C, Rose Bengal, Eoxin Red, Alizarin Lake and the like.

  Blue pigments include bitumen, cobalt blue, alkali blue rake, Victoria blue rake, fast sky blue, induslen blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxare. Rate and so on.

  Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake.

  Examples of the green pigment include chromium oxide, chromium green, pigment green, malachite green lake, final yellow green G, and the like.

  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.

  Moreover, dye can also be used as a coloring agent as needed. Examples of the dye include various dyes such as basic, acidic, dispersed, and direct dyes, such as nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue. Moreover, these can be used individually or in mixture, and also in the state of a solid solution.

  As the colorant, a cresol sulfonic acid formalin condensate represented by the above general formula (1) is used as a surfactant. For example, a rotary shear type homogenizer, a ball-type mill, a sand mill, an attritor or other media type disperser, a high-pressure counter-collision type Is dispersed in an aqueous solvent by a disperser or the like.

-Release agent-
The toner may contain a release agent as necessary. Low molecular weight polyolefins such as polyethylene, polypropylene, polybutene, silicones with softening point, fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide, carnauba wax, rice wax, candelilla wax , Plant waxes such as tree wax and jojoba oil, animal waxes such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax and other mineral and petroleum waxes, stearyl stearate , Ester waxes of higher fatty acids such as behenyl behenate and higher alcohols, butyl stearate, propyl oleate, glyceryl monostearate, glyceryl distearate, pentaerythris Ester waxes of higher fatty acids such as tall tetrabehenate and unit or polyhydric lower alcohols, higher fatty acids such as diethylene glycol monostearate, dipropylene glycol distearate, distearic diglyceride, tetrastearic triglyceride and polyhydric alcohols Examples include ester waxes composed of multimers, sorbitan higher fatty acid ester waxes such as sorbitan monostearate, and cholesterol higher fatty acid ester waxes such as cholesteryl stearate. These release agents may be used alone or in combination of two or more.

  The melting temperature of the release agent is preferably 50 ° C. to 100 ° C., more preferably 60 ° C. to 95 ° C.

  The content of the release agent in the toner is preferably 0.5 to 15% by mass, and more preferably 1.0 to 12% by mass. If the content of the release agent is less than 0.5% by mass, peeling failure may occur particularly in oilless fixing. When the content of the release agent is more than 15% by mass, the image quality and the reliability of image formation may be deteriorated, for example, the fluidity of the toner is deteriorated.

-Other additives-
In addition to the above components, the toner may contain various components such as an internal additive, a charge control agent, inorganic powder (inorganic particles), and organic particles as necessary.

  Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, manganese, and nickel, magnetic materials such as alloys, compounds containing these metals, and the like. An amount not used is used.

  The charge control agent is not particularly limited, but when a color toner is used, a colorless or light color is preferably used. Examples include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments. From the viewpoint of controlling strength and reducing wastewater contamination, a material that is difficult to dissolve in water is preferred.

  The inorganic particles and organic particles are external additives that are externally added to the toner surface, but are preferably added to the toner particle surface while being sheared. Specific examples include the following.

  Examples of inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, Examples include Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among them, silica particles and titanium oxide particles are desirable, and particles subjected to hydrophobic treatment (surface treatment) are particularly desirable.

  Inorganic particles are generally used for the purpose of improving fluidity. The primary particle size of the inorganic particles is desirably in the range of 1 to 200 nm, and the addition amount is desirably in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the toner.

  Organic particles are generally used for the purpose of improving cleaning properties and transfer properties. Specifically, for example, fluorine resin powders such as polyvinylidene fluoride and polytetrafluoroethylene, fatty acid metal salts such as zinc stearate and calcium stearate. , Polystyrene, polymethyl methacrylate and the like.

-Emulsion aggregation-
Hereinafter, a method for producing the toner for developing an electrostatic charge image of the exemplary embodiment will be described in detail by an emulsion aggregation method.

  In the emulsion aggregation method, generally, a dispersion of binder resin particles produced by emulsion polymerization or the like is mixed with a dispersion of ionic surfactant and a dispersion of colorant particles of an ionic surfactant, and a flocculant is added. Aggregation of the binder resin particles and the colorant particles is caused to form aggregated particles corresponding to the toner diameter. Next, the aggregated particles are fused and united by heating above the glass transition temperature of the binder resin particles, and washed and dried to obtain a toner. The toner shape can be manufactured from an irregular shape to a spherical shape. In the toner of this embodiment, a release agent particle dispersion can be added.

  The above production method is a method in which the raw material dispersions are mixed together and agglomerated and fused. However, the balance of the amount of the polar ionic surfactant is shifted in advance in the initial stage of the aggregation process. In addition, for example, an inorganic metal salt containing at least aluminum or a polymer containing at least aluminum is ionically neutralized to form core aggregated particles below the glass transition temperature. Depending on the necessity, after stabilization by slightly heating at a high temperature not higher than the glass transition temperature or melting temperature of the resin contained in the core agglomerated particles or additional particles, if necessary, the above-mentioned balance deviation may be performed as a second step. Add a polar and quantity particle dispersion to compensate for the resin, and if necessary, at a high temperature below the glass transition temperature of the resin contained in the core aggregated particles or additional particles After stabilizing by heating to or not, to coalescence while attached to the surface of the second stage added particles of core aggregated particles is heated above the glass transition temperature. In the following, description will be given in order.

  The binder resin particle dispersion is formed by applying a shearing force to a solution obtained by mixing an aqueous medium and a binder resin such as a polyester resin in addition to emulsion polymerization of a styrene-acrylic resin. At that time, by heating to a temperature equal to or higher than the softening point of the binder resin, the viscosity of the polymer liquid is lowered to form a particle dispersion.

  Examples of the disperser used when forming the binder resin particle dispersion include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. These dispersers are also used for mixing and agglomerating the binder resin particle dispersion and the colorant particle dispersion.

  Examples of the dispersion medium in the binder resin particle dispersion, the colorant particle dispersion, the release agent dispersion, and other components described later in the present embodiment include an aqueous medium.

  Examples of the aqueous medium include water such as distilled water and ion exchange water, alcohol, and the like. These may be used individually by 1 type and may use 2 or more types together.

  A surfactant may be used for the purpose of stabilizing the dispersion of each dispersion. Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap, cationic surfactants such as amine salt type and quaternary ammonium salt type, polyethylene glycol, etc. 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 this embodiment, the cresol sulfonic acid formalin condensate represented by the general formula (1) described above is used as the surfactant in the colorant particle dispersion. Therefore, the toner base particles according to the exemplary embodiment include a cresol sulfonic acid formalin condensate, and the measurement of the concentration of the cresol sulfonic acid formalin condensate in the toner base particles will be described in Examples described later. To do.

  Specific examples of anionic surfactants include fatty acid soaps such as potassium laurate, sodium oleate, and sodium castor oil, sulfate esters such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, and nonyl phenyl ether sulfate, lauryl sulfonate , Sodium alkylnaphthalenesulfonates such as dodecylbenzenesulfonate, triisopropylnaphthalenesulfonate, dibutylnaphthalenesulfonate, naphthalenesulfonate formalin condensate, monooctylsulfosuccinate, dioctylsulfosuccinate, lauric acid amide sulfonate, oleic acid amide sulfonate, etc. Sulfonates, lauryl phosphate, isopropyl phosphate, nonylphenyl ether Phosphoric acid esters such as phosphate, dialkyl sulfosuccinate salts such as sodium dioctyl sulfosuccinate, such as sulfosuccinate salts such as sodium lauryl sulfosuccinate 2.

  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, lauryl dihydroxyethylmethylammonium chloride, oleylbispolyoxyethylenemethylammonium chloride, lauroylaminopropyldimethylethylammonium ethosulphate, lauroylaminopropyldimethylhydroxyethylammonium perchlorate, alkylbenzene trimethylammonium chloride, alkyltrimethyl 4 such as ammonium chloride And ammonium salts and the like.

  The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant.

  Specific examples of the nonionic surfactant include polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether and other alkyl ethers, polyoxyethylene octyl phenyl ether, polyoxyethylene Alkyl phenyl ethers such as ethylene nonyl phenyl ether, polyoxyethylene laurate, polyoxyethylene stearate, alkyl esters such as 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, polyoxyethylene 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, 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 Etc.

  The said surfactant may be used individually by 1 type, and may be used in combination of 2 or more type. Further, the content of the surfactant in each dispersion is generally a small amount, specifically in the range of 0.01% by mass to 10% by mass, and more preferably 0.05% by mass. % To 5% by mass, more preferably 0.1% to 2% by mass. When the content is less than 0.01% by mass, each dispersion such as a resin particle dispersion, a colorant dispersion, and a release agent dispersion becomes unstable, so that aggregation occurs, and each particle during aggregation Since the stability between them is different, problems such as the release of specific particles may occur. In particular, when carbon black is used as the colorant, a conductive path is formed by the liberated carbon black, and the chargeability of the toner particles is deteriorated. On the other hand, if it exceeds 10% by mass, it is not preferable because the particle size distribution of the particles becomes wide and it becomes difficult to control the particle size. In general, a suspension polymerization toner dispersion having a large particle size is stable even if the amount of the surfactant used is small. As the amount of the surfactant is increased, the environmental stability of charging of the toner is lowered. Therefore, it is preferable that the addition amount of the surfactant is small.

  As described above, in this embodiment, the cresol sulfonic acid formalin condensate represented by the general formula (1) described above is added to the colorant particle dispersion as a surfactant. Has high dispersibility even in a small amount, and therefore, deterioration of the chargeability of the toner particles due to liberation of carbon black can be suppressed. In particular, when the amount of carbon black added is in the range of 8 to 15% by mass, the dispersibility of the pigment (carbon black) and the chargeability of the toner can be improved.

  In addition, an aqueous polymer that is solid at room temperature (25 ° C.) can also be used. Specifically, cellulose compounds such as carboxymethyl cellulose and hydroxypropyl cellulose, polyvinyl alcohol, gelatin, starch, gum arabic and the like are used.

  The particle size of the resin particles of the binder resin particle dispersion in the present embodiment is 1 μm or less in terms of volume average particle size, and is preferably in the range of 100 nm to 300 nm. When the volume average particle size exceeds 1 μm, the particle size distribution of toner particles obtained by agglomeration and fusion may be broadened, or free particles may be generated, resulting in a decrease in toner performance and reliability. If it is less than 100 nm, it may take time to coagulate and grow the toner, which may not be industrially suitable. If it exceeds 300 nm, the dispersion of the release agent and the colorant becomes non-uniform and control of the toner surface properties. May be difficult.

  In the emulsification aggregation method of the present embodiment, in the aggregation process, the binder resin particle dispersion, the colorant particle dispersion, and, if necessary, the particles in the release agent dispersion are aggregated to aggregate particles. Form. In this agglomeration step, an aggregating agent is added in order to obtain agglomerated particles stably and rapidly, or with a narrower particle size distribution.

  The aggregating agent is not particularly limited, but a metal salt of an inorganic acid is used in consideration of the stability of the agglomerated particles, the stability of the aggregating agent with respect to heat and time, and removal during washing. Specific examples include metal salts of inorganic acids such as magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, and sodium carbonate. In this embodiment, the final toner is used. From the viewpoint of controlling the viscosity at the time of fixing the particles, an aggregating agent containing aluminum (for example, polyaluminum chloride, aluminum sulfate, potassium alum, etc.) is preferable.

  The amount of the flocculant added varies depending on the valence of the electric charge, but all of them are small, and in the case of trivalent such as aluminum, it is about 0.5 mass% or less. Since the amount of the flocculant is preferably small, it is preferable to use a compound having a large valence.

  After the aggregation step, a coating layer may be formed by attaching binder resin particles to the surface of the formed aggregated particles (attachment step). Thereby, a toner having a core / shell structure constituted by a so-called core layer and a coating layer covering the core layer is obtained.

  The coating layer (shell layer) is formed by additionally adding a binder resin particle dispersion to the dispersion medium in which aggregated particles (core particles) are formed in the aggregation step.

  After the aggregation step, or the aggregation step and the adhesion step, the aggregated particles are united in the uniting step. In the coalescence process, under the same agitation as in the aggregation process, the pH of the suspension of aggregated particles is set in the range of 5 to 10 to stop the progress of aggregation, and in the aggregated particles in the solution. When the melting temperature of the binder resin contained in the resin is higher than the highest temperature, or when amorphous resin particles (including the shell layer constituting resin) are included, the glass transition temperature of the amorphous resin particles (type of resin) In the case of two or more types, the toner particles are obtained by heating to the glass transition temperature of the resin having the highest glass point transition temperature) and fusing and coalescing.

  There is no problem as long as the heating temperature in the coalescence process is equal to or higher than the glass transition temperature of the binder resin. The fusion / union can be advanced by preferably carrying out the glass transition temperature of the binder resin at + 10 ° C. or higher, more preferably + 15 ° C. or higher.

  Further, the heating time may be performed to the extent that coalescence is performed, and may be performed for 0.2 hours or more and 10 hours or less. Thereafter, when the temperature is lowered to the glass transition temperature or lower of the binder resin to solidify the particles, the particle shape and surface properties may change depending on the temperature lowering rate. For example, when the temperature is lowered at a high speed, the spheroidization and the surface are easily smoothed. On the other hand, when the temperature is slowly lowered, the particle shape becomes indefinite and irregularities are easily generated on the particle surface. Therefore, it is preferable to lower the temperature at a rate of at least 0.5 ° C./min, preferably at a rate of 1.0 ° C./min.

  After completion of the aggregation step and the coalescence step, toner is obtained as coalesced particles. The coalesced particles (toner) obtained by coalescence must be washed through a solid-liquid separation process such as filtration as described later.

  After the washing step, the toner particles of this embodiment are obtained through a solid-liquid separation step and a drying step. Although there is no restriction | limiting in particular in a solid-liquid separation process, From the point of productivity, suction filtration, pressure filtration, etc. are suitable. Further, the drying process is not particularly limited, but from the viewpoint of productivity, vacuum drying, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used.

  The toner for developing an electrostatic charge image of the present embodiment is produced by preparing toner particles (mother particles) as described above, adding the inorganic particles to the toner particles, and mixing them with a sample mill, a Henschel mixer or the like. Can be manufactured.

<Developer for developing electrostatic image>
The developer for developing an electrostatic charge image of this embodiment is not particularly limited except that it contains the toner for developing an electrostatic charge image of this embodiment, and can take a component composition according to the purpose. The developer for developing an electrostatic charge image of the present embodiment becomes a one-component developer for developing an electrostatic charge image when the toner for developing an electrostatic charge image is used alone, or a two-component electrostatic developer when used in combination with a carrier. It becomes a developer for charge image development.

  For example, in the case of a two-component system, the carrier to be used is not particularly limited, and a carrier known per se can be used. Examples thereof include known carriers such as resin-coated carriers described in JP-A Nos. 62-39879 and 56-11461.

  Specific examples of the carrier include the following resin-coated carriers. Examples of the core particle of the carrier include normal iron powder, ferrite, magnetite molding, and the like, and the volume average particle diameter is in the range of 30 μm to 200 μm.

  Examples of the coating resin for the resin-coated carrier include styrenes such as styrene, parachlorostyrene, and α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, and 2-ethylhexyl acrylate. , Α-methylene fatty acid monocarboxylic acids such as methyl methacrylate, n-propyl methacrylate, lauryl methacrylate and 2-ethylhexyl methacrylate, nitrogen-containing acrylics such as dimethylaminoethyl methacrylate, vinyl nitriles such as acrylonitrile and methacrylonitrile , Vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone Homopolymers such as vinyl ketones such as ethylene, olefins such as ethylene and propylene, vinyl fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene, or copolymers composed of two or more types of monomers, , Silicone resins including methylsilicone, methylphenylsilicone, etc., polyesters containing bisphenol, glycol, etc., epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like.

  These resins may be used alone or in combination of two or more.

  The coating amount of the coating resin is preferably in the range of 0.1 to 10 parts by mass and more preferably in the range of 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the core particles. .

  For the production of the carrier, a heating kneader, a heating type Henschel mixer, a UM mixer, or the like is used. Depending on the amount of the coating resin, a heating type fluidized rolling bed, a heating type kiln, or the like is used.

  The mixing ratio (mass ratio) of the electrostatic image developing toner of this embodiment and the carrier in the two-component electrostatic image developing developer is not particularly limited and is selected according to the purpose. The range of carrier = 1: 100 to 30: 100 is desirable, and the range of 3: 100 to 20: 100 is more desirable.

<Image forming apparatus>
The image forming apparatus according to the embodiment includes an image carrier, a latent image forming unit that forms an electrostatic latent image on the surface of the image carrier, and a developer (electrostatic image developing developer) for the electrostatic latent image. A developing unit that forms a toner image by developing the toner image; a transfer unit that transfers the developed toner image to a transfer target; and a fixing unit that fixes the toner image transferred to the surface of the transfer target. The developer for developing an electrostatic image is used as the agent. The image forming apparatus according to the embodiment may include means other than the above means, for example, a charging means for charging the image holding member, a cleaning means for removing toner remaining on the surface of the image holding member.

  An example of the image forming apparatus according to the embodiment is schematically shown in FIG. The image forming apparatus 1 includes a charging unit 10, an exposure unit 12, an electrophotographic photosensitive member 14 that is an image holding member, a developing unit 16, a transfer unit 18, a cleaning unit 20, and a fixing unit 22.

  In the image forming apparatus 1, the charging unit 10 that is a charging unit that charges the surface of the electrophotographic photosensitive member 14 and the charged electrophotographic photosensitive member 14 are exposed around the electrophotographic photosensitive member 14 according to image information. An exposure unit 12 that is a latent image forming unit that forms an electrostatic latent image (electrostatic charge image), a developing unit 16 that is a developing unit that develops the electrostatic latent image with toner and forms a toner image, and electrophotography. A transfer unit 18 that is a transfer unit that transfers the toner image formed on the surface of the photoconductor 14 to the surface of the transfer target 24, and a cleaning unit that removes the toner remaining on the surface of the electrophotographic photoconductor 14 after transfer. A certain cleaning unit 20 is arranged in this order. A fixing unit 22 that is a fixing unit that fixes the toner image transferred to the transfer target 24 is arranged on the left side of the transfer unit 18.

  An operation of the image forming apparatus 1 according to the present embodiment will be described. First, the surface of the electrophotographic photosensitive member 14 is uniformly charged by the charging unit 10 (charging process). Next, light is applied to the surface of the electrophotographic photosensitive member 14 by the exposure unit 12, and the charged charges in the irradiated portion are removed, and an electrostatic charge image (electrostatic latent image) is formed according to the image information. (Latent image forming step). Thereafter, the electrostatic charge image is developed by the developing unit 16, and a toner image is formed on the surface of the electrophotographic photosensitive member 14 (developing step). For example, in the case of a digital electrophotographic copying machine using an organic photoconductor as the electrophotographic photoconductor 14 and using a laser beam as the exposure unit 12, the surface of the electrophotographic photoconductor 14 is negatively charged by the charging unit 10. Then, a digital latent image is formed in a dot shape by the laser beam light, and toner is applied to the portion irradiated with the laser beam light by the developing unit 16 to be visualized. In this case, a negative bias is applied to the developing unit 16. Next, a transfer member 24 such as paper is superposed on the toner image at the transfer unit 18, and a charge opposite in polarity to the toner is applied to the transfer member 24 from the back side of the transfer member 24, and the toner image is generated by electrostatic force. Is transferred to the transfer target 24 (transfer process). The transferred toner image is heated and pressed by a fixing member in the fixing unit 22 and is fused and fixed to the transfer target 24 (fixing step). On the other hand, toner remaining on the surface of the electrophotographic photoreceptor 14 without being transferred is removed by the cleaning unit 20 (cleaning step). One cycle is completed in a series of processes from charging to cleaning. In FIG. 1, the toner image is directly transferred to the transfer target 24 such as a sheet by the transfer unit 18, but may be transferred via a transfer member such as an intermediate transfer member.

  Hereinafter, the charging unit, the image carrier, the exposure unit, the developing unit, the transfer unit, the cleaning unit, and the fixing unit in the image forming apparatus 1 of FIG. 1 will be described.

(Charging means)
For example, a charging device such as a corotron as shown in FIG. 1 is used as the charging unit 10 as a charging unit, but a conductive or semiconductive charging roll may be used. A contact charger using a conductive or semiconductive charging roll may apply a direct current to the electrophotographic photosensitive member 14 or may superimpose an alternating current. For example, the charging unit 10 charges the surface of the electrophotographic photosensitive member 14 by generating a discharge in a minute space near the contact portion with the electrophotographic photosensitive member 14. Normally, it is charged to -300 to -1000V. The conductive or semiconductive charging roll may have a single layer structure or a multiple structure. Further, a mechanism for cleaning the surface of the charging roll may be provided.

(Image carrier)
The image carrier has a function of forming at least a latent image (electrostatic charge image). As the image carrier, an electrophotographic photosensitive member 14 is preferably exemplified. The electrophotographic photoreceptor 14 has a coating film containing an organic photoreceptor or the like on the outer peripheral surface of a cylindrical conductive substrate. The coating film is a substrate in which a subbing layer and a photosensitive layer including a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material are formed in this order on the substrate as necessary. is there. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single-layer type photoreceptor included in the above layer may be used, and a laminated photoreceptor is preferable. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. In addition, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used in addition to the organic photoreceptor.

(Exposure means)
There are no particular limitations on the exposure unit 12 that is an exposure means. For example, an optical device that can expose a light source such as semiconductor laser light, LED light, or liquid crystal shutter light on the surface of the image carrier in a desired image manner. Can be mentioned.

(Development means)
The developing unit 16 serving as a developing unit has a function of developing a latent image formed on the image carrier with a developer containing toner to form a toner image. Such a developing device is not particularly limited as long as it has the above-mentioned function, and can be appropriately selected according to the purpose. For example, toner for developing an electrostatic image is used using a brush, a roller, or the like. A known developing device having a function of adhering to the electrophotographic photosensitive member 14 may be used. For the electrophotographic photosensitive member 14, a DC voltage is usually used, but an AC voltage may be superimposed and used.

(Transfer means)
As the transfer unit 18 serving as a transfer unit, for example, a charge having a polarity opposite to that of the toner is applied to the transfer target 24 from the back side of the transfer target 24 as shown in FIG. A transfer roll and a transfer roll pressing device using a conductive roll or a semiconductive roll that transfers directly to the surface of the transferred body 24 via the transferred body 24 can be used. . A direct current may be applied to the transfer roll as a transfer current applied to the image carrier, or an alternating current may be applied in a superimposed manner. The transfer roll can be arbitrarily set depending on the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed (circumferential speed), and the like. Further, a single layer foam roll or the like is suitably used as a transfer roll for cost reduction. As a transfer method, a method of transferring directly to the transfer target 24 such as paper or a method of transferring to the transfer target 24 via an intermediate transfer member may be used.

  A known intermediate transfer member can be used as the intermediate transfer member. Materials used for the intermediate transfer member include polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene terephthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend materials, and the like can be mentioned. From the viewpoint of mechanical strength, an intermediate transfer belt using a thermosetting polyimide resin is preferable.

(Cleaning means)
The cleaning unit 20 serving as a cleaning unit may be appropriately selected such as one that employs a blade cleaning method, a brush cleaning method, or a roll cleaning method as long as the toner remaining on the image carrier is cleaned. Among these, it is preferable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber. Among them, it is particularly preferable to use a polyurethane elastic body because of its excellent wear resistance. However, there may be a mode in which the cleaning unit 20 is not used when toner having high transfer efficiency is used.

(Fixing means)
The fixing unit 22 that is a fixing unit (image fixing device) fixes the toner image transferred to the transfer medium 24 by heating, pressing, or heating and pressing, and includes a fixing member.

(Transfer)
Examples of the transfer target (paper) 24 to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines, printers, and the like. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer target is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Can be preferably used.

  In the example of FIG. 1, one electrophotographic photosensitive member 14 is drawn, but the present invention is not limited to this. For example, the charging unit 10, the exposure unit 12, the electrophotographic photosensitive member 14, the developing unit 16, the transfer unit 18, and the cleaning unit 20 are provided in four units, and toners of C, M, Y, and K colors are provided. A four-tandem system in which an image is transferred to the intermediate transfer member and then a color image is transferred and fixed on the transfer member.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these Examples. In the following description, “part” represents “part by mass” and “%” represents “% by mass” unless otherwise specified.

-Production of binder resin particle dispersion (A)-
Styrene (Wako Pure Chemical Industries, Ltd.) 280 parts by mass n-butyl acrylate
120 parts by mass β-carboxyethyl acrylate (manufactured by Rhodia Nikka Co., Ltd.)
9 parts by mass 1'10 decanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) 1.5 parts by mass dodecanethiol (manufactured by Wako Pure Chemical Industries, Ltd.)
2.7 parts by mass

  A surfactant solution in which 4 parts by weight of an anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Co., Ltd.) is dissolved in 550 parts by weight of ion-exchanged water is prepared by mixing and dissolving the above components in advance. Into a flask, 413.2 parts by mass of the above solution was added, dispersed, emulsified, and slowly stirred and mixed for 10 minutes, and then 50 parts by mass of ion-exchanged water in which 6 parts by mass of ammonium persulfate had been dissolved was added. Next, after the inside of the system was sufficiently replaced with nitrogen, the flask was heated with an oil bath while stirring until the inside of the system reached 70 ° C., and emulsion polymerization was continued for 5 hours to obtain a resin fine particle dispersion 1. When the resin fine particles were separated from the resin fine particle dispersion and examined for physical properties, the center diameter (volume median diameter) was 200 nm, the solid content in the dispersion was 41%, the glass transition temperature was 51.7 ° C., and the weight average molecular weight Mw. Was 33,000.

-Production of binder resin particle dispersion (B)-
In the preparation of the binder resin particle dispersion (A), 4 parts by weight of an anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Co., Ltd.) was added to a cresolsulfonic acid formalin condensate (Damol SC-30 manufactured by Kao Corporation). A binder resin particle dispersion (B) was obtained based on the production of the binder resin particle dispersion (A) except that the amount was changed to 3 parts by mass. The center diameter was 165 nm, the solid content in the dispersion was 41% by mass, the glass transition temperature was 51.7 ° C., and the weight average molecular weight Mw was 20000.

-Preparation of colorant particle dispersion (A)-
Carbon black (Cabot Corporation: R330) 45 parts by mass Cresol sulfonic acid formalin condensate 7.2 parts by mass (Kao Co., Ltd .: DEMAL SC-30)
200 parts by mass of ion exchange water

  The above was mixed and dissolved, and dispersed for 10 minutes with a homogenizer (manufactured by IKA: Ultra Tarrax), then irradiated with 28 kHz ultrasonic waves for 10 minutes using an ultrasonic disperser, solid content 20%, center particle size 125 nm A colorant particle dispersion (A) was obtained.

-Preparation of colorant particle dispersion (B)-
Carbon black (Cabot Corporation: R330) 45 parts by weight Anionic surfactant Neogen SC (Daiichi Kogyo Seiyaku Co., Ltd.) 7.2 parts by weight Deionized water 200 parts by weight

  The above was mixed and dissolved, dispersed for 10 minutes with a homogenizer (IKA: Ultra Tarrax), then irradiated with 28 kHz ultrasonic waves for 10 minutes using an ultrasonic disperser, solid content 20%, central particle size 130 nm A colorant particle dispersion was obtained.

-Preparation of colorant particle dispersion (C)-
Carbon black (manufactured by Cabot: R330) 45 parts by mass Anionic surfactant Neogen SC (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 24 parts by mass Ion-exchanged water 200 parts by mass

  The above was mixed and dissolved, dispersed for 10 minutes with a homogenizer (IKA: Ultra Tarrax), then irradiated with 28 kHz ultrasonic waves for 10 minutes using an ultrasonic disperser, solid content 20%, central particle size 130 nm A colorant particle dispersion (C) was obtained.

-Preparation of colorant particle dispersion (D)-
Quinacridone pigment (manufactured by Dainichi Seika Co., Ltd .: ECR-186Y) 45 parts by mass Cresol sulfonic acid formalin condensate 7.2 parts by mass (manufactured by Kao Corporation: Demol SC-30)
200 parts by mass of ion exchange water

  The above were mixed and dissolved, dispersed for 10 minutes with a homogenizer (IKA Corp .: Ultra Turrax T50), then irradiated with 28 kHz ultrasonic waves for 10 minutes using an ultrasonic disperser, solid content 20%, center particle size A 115 nm colorant particle dispersion (D) was obtained.

-Preparation of colorant particle dispersion (E)-
Quinacridone pigment (manufactured by Dainichi Seika Co., Ltd .: ECR-186Y) 45 parts by mass Anionic surfactant Neogen SC (Daiichi Kogyo Seiyaku Co., Ltd.) 24 parts by mass Ion-exchanged water 200 parts by mass

  The above were mixed and dissolved, dispersed for 10 minutes with a homogenizer (IKA Corp .: Ultra Turrax T50), then irradiated with 28 kHz ultrasonic waves for 10 minutes using an ultrasonic disperser, solid content 20%, center particle size A 120 nm colorant particle dispersion (E) was obtained.

-Preparation of colorant particle dispersion (F)-
Carmine pigment 45 parts by mass (manufactured by Sanyo Pigment Co., Ltd .: PERMANENT CARLINE 3810)
Cresol sulfonic acid formalin condensate 7.2 parts by mass (Kao Corporation: DEMAL SC-30)
200 parts by mass of ion exchange water

  The above were mixed and dissolved, dispersed for 10 minutes with a homogenizer (IKA: Ultra Turrax T50), then irradiated with 28 kHz ultrasonic waves for 10 minutes using an ultrasonic disperser, solid content 20%, center particle size A 120 m colorant particle dispersion (F) was obtained.

-Preparation of colorant particle dispersion (H)-
Carmine pigment 45 parts by mass (manufactured by Sanyo Dye Co., Ltd .: PERMANENT CARLINE 3810)
Anionic surfactant Neogen SC (Daiichi Kogyo Seiyaku Co., Ltd.) 24 parts by mass Ion-exchanged water 200 parts by mass

  The above was mixed and dissolved, dispersed for 10 minutes with a homogenizer (manufactured by IKA: Ultra Tarrax), then irradiated with ultrasonic waves of 28 kHz for 10 minutes using an ultrasonic disperser, solid content 20%, center particle size 120 m A colorant particle dispersion (H) was obtained.

-Production of release agent particle dispersion (A)-
45 parts by weight of polyethylene wax (manufactured by Baker Petrolite: POLYWAX725, melting point 103 ° C.)
Anionic surfactant Neogen SC (Daiichi Kogyo Seiyaku Co., Ltd.) 5 parts by weight Ion-exchanged water 200 parts by weight

  The above components were heated to 120 ° C. and dispersed with a pressure discharge homogenizer (manufactured by Niro Soavi: NS3006H type) to obtain a release agent dispersion (A) having a solid content of 20% and a center particle size of 226 nm.

-Preparation of release agent particle dispersion (B)-
45 parts by weight of polyethylene wax (Baker Petrolite, POLYWAX725: melting point 103 ° C.)
Cresolsulfonic acid formalin condensate 7.2 parts by mass (Kao Co., Ltd., Demol SC-30)
200 parts by mass of ion exchange water

  The above components were heated to 120 ° C. and dispersed with a pressure discharge type homogenizer (manufactured by Niro Soavi: NS3006H type) to obtain a release agent dispersion (A) having a solid content of 20% and a center particle size of 220 nm.

(Creation of carrier)
100 parts by mass of ferrite particles (manufactured by Powdertech, average particle size 50 μm) and 1.5 parts by mass of polymethyl methacrylate resin (manufactured by Mitsubishi Rayon Co., Ltd., molecular weight 95,000, component ratio of 10,000 or less) are 500 parts by mass of toluene. The mixture is stirred and mixed at room temperature for 15 minutes, heated to 70 ° C. while mixing under reduced pressure to distill off toluene, then cooled, classified using a 105 μm sieve, and coated with a resin-coated ferrite carrier. Got.

(Example 1)
Binder resin particle dispersion (A) 273 parts by weight Colorant particle dispersion (A) 50 parts by weight Release agent dispersion (A) 90 parts by weight Polyaluminum chloride 10% solution 3.0 parts by weight Ion exchange water 660 parts by weight Part

  After thoroughly mixing and dispersing 1076 parts by mass of the above component in a round stainless steel flask with a homogenizer (IKA: Ultra Tarrax T50), the flask was heated to 42 ° C. with stirring in an oil bath for heating. Holding at 60 ° C. for 60 minutes, an aggregated particle dispersion was prepared. 146 parts by mass of the binder resin particle dispersion (A) was gradually added to the aggregated particle dispersion.

  Thereafter, a 0.5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH in the system to 6.5, and then the mixture was heated to 96 ° C. and maintained for 5 hours while stirring was continued. After cooling, filtration, re-dispersion in 3 liters of ion exchange water, and solid-liquid separation by Nutsche suction filtration were repeated 6 times to obtain a wet cake. Subsequently, vacuum drying was performed for 12 hours to obtain toner base particles having an average volume particle size of 3.5 μm.

  Next, 1.5 parts by mass of hydrophobic silica (manufactured by Cabot: TS720) was added to 50 parts by mass of the toner base particles, and blended by a sample mill to obtain an externally added toner. Next, the externally added toner and the resin-coated ferrite carrier were mixed to prepare a developer having a toner concentration of 7% by weight.

(Example 2)
Binder resin particle dispersion (A) 243 parts by weight Colorant particle dispersion (A) 80 parts by weight Release agent dispersion (A) 90 parts by weight Polyaluminum chloride 10% solution 3.0 parts by weight Ion exchange water 660 parts by weight Part

  After thoroughly mixing and dispersing 1076 parts by mass of the above component in a round stainless steel flask with a homogenizer (IKA: Ultra Tarrax T50), the flask was heated to 42 ° C. with stirring in an oil bath for heating. Holding at 60 ° C. for 60 minutes, an aggregated particle dispersion was prepared. 146 parts by mass of the binder resin particle dispersion (A) was gradually added to the aggregated particle dispersion. Thereafter, a 0.5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH in the system to 6.5, and then the mixture was heated to 96 ° C. and maintained for 5 hours while stirring was continued. After cooling, filtration, re-dispersion in 3 liters of ion exchange water, and solid-liquid separation by Nutsche suction filtration were repeated 6 times to obtain a wet cake. Subsequently, vacuum drying was performed for 12 hours to obtain toner base particles having an average volume particle size of 3.5 μm.

  Next, 1.5 parts by mass of hydrophobic silica (manufactured by Cabot: TS720) was added to 50 parts by mass of the toner base particles, and blended by a sample mill to obtain an externally added toner. Next, the externally added toner and the resin-coated ferrite carrier were mixed to prepare a developer having a toner concentration of 7% by weight.

(Example 3)
Binder resin particle dispersion (A) 233 parts by weight Colorant particle dispersion (A) 100 parts by weight Release agent dispersion (A) 90 parts by weight Polyaluminum chloride 10% solution 3.0 parts by weight Ion exchange water 660 parts by weight Part

  After thoroughly mixing and dispersing 1076 parts by mass of the above component in a round stainless steel flask with a homogenizer (IKA: Ultra Tarrax T50), the flask was heated to 42 ° C. with stirring in an oil bath for heating. Holding at 60 ° C. for 60 minutes, an aggregated particle dispersion was prepared. 146 parts by mass of the binder resin particle dispersion (A) was gradually added to the aggregated particle dispersion. Thereafter, a 0.5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH in the system to 6.5, and then the mixture was heated to 96 ° C. and maintained for 5 hours while stirring was continued. After cooling, filtration, re-dispersion in 3 liters of ion exchange water, and solid-liquid separation by Nutsche suction filtration were repeated 6 times to obtain a wet cake. Subsequently, vacuum drying was performed for 12 hours to obtain toner base particles having an average volume particle size of 3.5 μm.

  Next, 1.5 parts by mass of hydrophobic silica (manufactured by Cabot: TS720) was added to 50 parts by mass of the toner base particles, and blended by a sample mill to obtain an externally added toner. Next, the externally added toner and the resin-coated ferrite carrier were mixed to prepare a developer having a toner concentration of 7% by weight.

Example 4
Except that the aggregated particle dispersion was adjusted at 52 ° C., toner mother particles having an average volume particle diameter of 5.8 μm, an externally added toner and a developer were obtained in the same manner as in Example 2.

(Example 5)
Except that the aggregated particle dispersion was adjusted at 30 ° C., toner mother particles having an average volume particle size of 2.0 μm, an externally added toner and a developer were obtained in the same manner as in Example 2.

(Example 6)
Except that the aggregated particle dispersion was adjusted at 28 ° C., toner mother particles having an average volume particle size of 1.8 μm, an externally added toner and a developer were obtained in the same manner as in Example 2.

(Example 7)
In place of the colorant particle dispersion (A), an average volume particle diameter of 3.3 in the same manner as in Example 2 except that a colorant particle dispersion (D) containing a pigment having higher lipophilicity than carbon black was used. 5 [mu] m toner base particles, externally added toner and developer were obtained.

(Example 8)
In place of the colorant particle dispersion (A), an average volume particle diameter of 3.3 in the same manner as in Example 1 except that a colorant particle dispersion (F) containing a pigment having a hydrophilicity higher than that of carbon black was used. 5 [mu] m toner base particles, externally added toner and developer were obtained.

Example 9
The colorant particle dispersion (A) is used, the binder resin particle dispersion (B) is used instead of the binder resin particle dispersion (A), and the release agent is used instead of the release agent particle dispersion (A). Except that the particle dispersion (B) was used, toner mother particles having an average volume particle size of 3.5 μm, an externally added toner and a developer were obtained in the same manner as in Example 2.

(Comparative Example 1)
A toner base particle having an average volume particle size of 3.5 μm, an externally added toner and a developer in the same manner as in Example 1 except that the colorant particle dispersion liquid (B) was used instead of the colorant particle dispersion liquid (A). Got.

(Comparative Example 2)
A toner base particle having an average volume particle size of 3.5 μm, an externally added toner and a developer in the same manner as in Example 2 except that the colorant particle dispersion liquid (B) was used instead of the colorant particle dispersion liquid (A). Got.

(Comparative Example 3)
A toner base particle having an average volume particle size of 3.5 μm, an externally added toner and a developer in the same manner as in Example 2 except that the colorant particle dispersion liquid (C) was used instead of the colorant particle dispersion liquid (A). Got.

(Comparative Example 4)
In place of the colorant particle dispersion (A), an average volume particle diameter of 3.3 in the same manner as in Example 2 except that the colorant particle dispersion (E) containing a pigment having higher lipophilicity than carbon black was used. 5 [mu] m toner base particles, externally added toner and developer were obtained.

(Comparative Example 5)
In place of the colorant particle dispersion (A), a colorant particle dispersion (H) containing a pigment having higher hydrophilicity than carbon black was used in the same manner as in Example 2, except that the average volume particle size 3. 5 [mu] m toner base particles, externally added toner and developer were obtained.

(Method for measuring cresolsulfonic acid formalin condensate)
The cresolsulfonic acid formalin condensate contained in the toner base particles can be measured and quantified by the following procedure.

  1 g of toner was precisely weighed, 10 g of methanol was added and the mixture was treated for 20 minutes in an ultrasonic cleaner maintained at a water temperature of 30 ° C. ± 2 ° C., and then filtered to extract the surfactant into methanol. 10.0 [mu] l of this methanol solution was subjected to high performance liquid chromatography (Hitachi high performance liquid chromatograph LaChromElite (L-2000 series) manufactured by Hitachi High-Technologies Corporation). At that time, GL Science InertSil Ph (5 μ) φ4.6 × 250 mm was used as the column, and the column was kept at a temperature of 50 ° C. ± 1 ° C. in a column oven. A surfactant (cresolsulfonic acid formalin condensate) was detected by fractionating a mixed solvent of 0.1 volume% phosphoric acid 80 volumes / acetonitrile 20 volumes as a mobile phase at a liquid feed rate of 1.0 ml / min. The amount of the surfactant was quantified using a calibration curve prepared in advance from the wavelength absorbance at 224 nm using a UV detector.

(Colorant dispersion evaluation)
The cross section of the toner particles was observed with a transmission electron microscope, and the dispersion state of the colorant in the toner particles was evaluated. The evaluation criteria are as follows.
○: Colorant particles are uniformly dispersed with respect to toner particles.
Δ: Colorant aggregation is observed in the toner particles, but is practically usable.
X: Aggregation of a large colorant is observed in the toner particles, and is practically unusable.

(Image evaluation method)
Each developer obtained was set in a developing device of DocuCentre-IIC3300 manufactured by Fuji Xerox Co., Ltd. in an environmental chamber at a room temperature of 32 ° C. and a humidity of 75%, and 50,000 sheets were continuously printed out. The background fog was evaluated. As paper, C2 paper manufactured by Fuji Xerox Interfield, Inc. was used, and images containing Japanese characters including 4-point and 6-point kanji were formed.

―Evaluation of fogging―
After continuous printout of 50000 sheets, the fog was evaluated visually, and the following G1 to G5 were evaluated by comparison with a limit sample. Usually, if it is G2 or less, it can be determined that there is no problem in image quality. Note that fogging is a phenomenon in which toner is attached to a portion where there is no latent image where an image does not appear as an original image and the polarity is reversed due to a decrease in toner charge.
G1: No fog is observed.
G2: Although fog is observed with a loupe, there is no problem in actual use.
G3: Can be confirmed visually.
G4: It is easily observed visually.
G5: fog is observed wisely.

-Image density evaluation-
After continuous printing of 50000 sheets, the image density of the character image was measured with an X-rite 404 densitometer. In addition, if the image density is 1.20, it is a level with no problem.

-Evaluation of toner chargeability-
Remove the developer after printing out 50000 sheets continuously, adjust the amount of toner to 4% of the total amount of developer, and blow off the charge amount when stirred in an environmental chamber at room temperature of 32 ° C and humidity of 75% for 1 minute. This was confirmed by the method (Toshiba Chemical Co., Ltd .: TB-200). Note that air was used as the gas at this time.

-Evaluation criteria for toner chargeability-
A: When the charge amount is 30 μC / g or more in absolute value.
A: When the charge amount is 15 μC / g or more and less than 30 μC / g in absolute value.
Δ: Charge amount is less than 15 μC / g in absolute value.

The above evaluation results are shown in Table 1.

  In Table 1, Examples 1 to 8 use a cresol sulfonic acid formalin condensate in a colorant particle dispersion, and Example 9 is a binder resin particle dispersion, a colorant particle dispersion, and a release agent particle dispersion. Cresol sulfonic acid formalin condensate is used in any of the liquids. On the other hand, in Comparative Examples 1 to 5, no cresol sulfonic acid formalin condensate is used in any of the dispersions. For this reason, in Examples 1 to 9, the pigment dispersibility and the toner chargeability are both better than the comparative examples. This is because at least the cresol sulfonic acid formalin condensate is used as the surfactant of the colorant particle dispersion, whereby the colorant particles in the toner base particles (Examples 1 to 6 and 9 are carbon black, Example 7 is This is because the dispersibility of the quinacridone pigment (Example 8 is a carmine pigment) was improved. When the dispersibility of the colorant particles is improved, a conductive path is hardly formed in the toner base particles, and the toner charging property is improved. Moreover, since the dispersibility of a coloring agent improves with a cresol sulfonic-acid formalin condensate, the usage-amount of a cresol sulfonic-acid formalin condensate and other surfactant (For example, neogen SC used in Comparative Examples 1-5) and In comparison, it can be relatively reduced. As a result, the amount of the surfactant remaining in the toner base particles can be reduced, and the environmental stability of the toner charging property can be improved. In each of the examples and comparative examples, the toner chargeability is evaluated by stirring in an environmental chamber with a humidity of 75%. The toner chargeability of each example is better than that of the comparative example. One reason is that the amount of activator could be reduced.

  The amount of carbon black used is Example 1 (50 parts by mass) <Example 2 (80 parts by mass) <Example 3 (100 parts by mass). In either case, pigment dispersion and toner chargeability are good. It is. Increasing the amount of carbon black tends to cause a decrease in chargeability due to the formation of a conductive path, but toner chargeability did not decrease even at 100 parts by mass (Example 3). Also from this point, it can be seen that the dispersibility of the cresolsulfonic acid formalin condensate is good.

  Also, in terms of fogging evaluation, Examples 1-4 and Examples 7-9 were as good as G1. This is because the dispersibility of the colorant is improved by the cresol sulfonic acid formalin condensate, and as a result, the charging property of the toner base particles is improved, thereby suppressing the polarity of the toner base particles from being reversed. . Moreover, although Example 5 was G2 and Example 6 was G3, since the aggregate particle dispersion was prepared at 30 ° C. in Example 5 and 28 ° C. in Example 6, the particle size was reduced ( In Example 5, the average volume particle size is 2.0 μm, and in Example 6, the average volume particle size is 1.8 μm. The charge amount of each toner base particle (the charge amount per toner particle, not per unit weight) is small. Because it becomes. However, each of Comparative Examples 2 to 5 has an average volume particle size of 3.5 μm, which is larger than Examples 5 and 6 and is advantageous in suppressing fogging. The fog evaluation was bad (G3 to G5). In Comparative Example 1, the fogging evaluation was G1, but this is because the amount of the colorant particle dispersion liquid of Comparative Example 1 is as small as 50 parts by mass, and the amount of carbon black used is small. This is because a decrease in toner chargeability due to the formation of the conductive path is suppressed (toner chargeability evaluation is “good”), and reversal of the polarity of the toner base particles is suppressed. However, since the amount of carbon black used is small, the image density is 1.25, which is lower than in each example.

  In addition, in the evaluation of the image density, all the examples have good results (the image density is 2 or more except for Examples 1 and 4). This is because the color developability of the toner is improved because the dispersibility of the colorant particles in the toner base particles by the cresolsulfonic acid formalin condensate is improved. Although the image density of Example 1 is 1.50 and the image density of Example 4 is 1.38, the image density exceeds 1.20, and there is no practical problem. The image density is lower than that of the other examples. In Example 1, the amount of the colorant particle dispersion used is 50 mass parts, and in Example 4, the average volume particle size of the toner base particles is low. This is because it is 5.8 μm, which is larger than the other examples. However, in Example 1, the image density is higher than that of Comparative Example 1 in which the amount of the colorant particle dispersion used is the same. In Example 4, the image density is higher than that of Comparative Example 2 which is common except that the preparation temperature of the aggregated particle dispersion and the surfactant used in the colorant particle dispersion are different.

  On the other hand, in Comparative Examples 1 to 5, the image density does not exceed 2 except for Comparative Example 3. This is because cresol sulfonic acid formalin condensate is not used as a surfactant, so that the dispersibility of the colorant particles cannot be improved as much as in the examples. For example, in Comparative Examples 1 and 2, carbon black is used as a colorant, but other surfactants (Neogen SC) of the same amount (7.2 parts by mass) as the cresolsulfonic acid formalin condensate are sufficient. Dispersibility could not be secured. In Comparative Examples 4 and 5, the amount of neogen SC used was increased to 24 parts by mass, but sufficient dispersibility was obtained for the quinacridone pigment (Comparative Example 4) and the carmine pigment (Comparative Example 5). I couldn't. The image density of Comparative Example 3 was 2.10 because carbon black was used as the colorant and the amount of surfactant (Neogen SC) used was increased to 24 parts by mass. As a result, the pigment dispersibility is improved (◯), but the toner chargeability is deteriorated (Δ) because the amount of the surfactant used is increased. As a result, the fog evaluation is also deteriorated to G5.

  DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 10 charging part, 12 exposure part, 14 electrophotographic photosensitive member, 16 developing part, 18 transfer part, 20 cleaning part, 22 fixing part, 24 to-be-transferred body.

Claims (4)

A toner for developing an electrostatic charge image, comprising at least a binder resin, a colorant, a release agent, and a cresolsulfonic acid formalin condensate represented by the following general formula (1).

  An electrostatic charge image developing developer comprising the electrostatic charge image developing toner according to claim 1 and a carrier. A mixing step of mixing a dispersion of binder resin particles having a volume average particle size of 1 μm or less and a dispersion of colorant particles;
An aggregating step of aggregating the binder resin particles and the colorant particles by adding an aggregating agent;
A coalescence step of coalescing the aggregated particles at a temperature equal to or higher than the melting point of the binder resin that is the main component of the binder resin particles after the aggregation step;
And a dispersion of the colorant particles contains a cresol sulfonic acid formalin condensate. An image carrier,
Latent image forming means for forming an electrostatic latent image on the surface of the image carrier;
Developing means for developing the electrostatic latent image with the developer for developing an electrostatic charge image according to claim 2 to form a toner image;
Transfer means for transferring the toner image formed on the image carrier onto a transfer target;
Fixing means for fixing the toner image transferred onto the transfer target;
An image forming apparatus comprising:

Images