JP2010217354A - Toner for developing electrostatic charge image and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner for developing electrostatic charge image capable of achieving excellent durability in printing and excellent reproducibility of fine line even under high temperature and high humidity as well as normal temperature and normal humidity and to provide a method of manufacturing the same. <P>SOLUTION: This toner for developing electrostatic charge image includes colored polymer particles containing a fixing resin, a coloring agent, a charging control agent, and a release agent. This toner has (1) amount of fatty acid A of 50-6,000 ppm when an extract prepared by extracting this toner by the Soxhlet extraction method is measured by a gas chromatograph mass spectrometer by using this toner as reference and (2) amount of fatty acid B of less than 50 ppm when an extract prepared by extracting this toner after its alkali cleaning by the Soxhlet extraction method is measured by the gas chromatograph mass spectrometer by using this toner as reference. A method for manufacturing this toner is provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image used as a developer for visualizing an electrostatic latent image formed on a photoreceptor in an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, or a facsimile. The present invention relates to a developing toner and a manufacturing method thereof. More specifically, the present invention relates to a toner for developing an electrostatic charge image that is remarkably excellent in printing durability and fine line reproducibility not only in a normal temperature and normal humidity environment but also in a high temperature and high humidity environment, and a method for producing the same.

  In image forming apparatuses such as electrophotographic (including electrostatic recording) copying machines, laser beam printers, facsimiles, etc., developers are used to visualize electrostatic latent images formed on photoreceptors. It has been. The developer is mainly composed of colored particles (toner) in which a colorant, a charge control agent, a release agent and the like are dispersed in a binder resin. The toner is called an electrostatic charge image developing toner because of its function.

  The toner production method can be roughly divided into a pulverization method and a polymerization method. In the pulverization method, a toner (ground toner) made of colored resin particles is manufactured by a method in which a binder resin, a colorant, and other additive components are melt-kneaded, and the melt is pulverized and classified. Examples of the polymerization method include a suspension polymerization method, an emulsion polymerization aggregation method, a dispersion polymerization method, and a dissolution suspension method. According to the polymerization method, it is generally possible to produce a toner having a sharp particle size distribution with a particle size on the order of microns. According to the polymerization method, it is possible to obtain a polymerized toner having a small particle diameter, a spherical shape, and a sharp molecular weight distribution. Small particle size and spherical polymerized toners are excellent in transferability and dot reproducibility, and can form high-definition images.

  Since the electrophotographic image forming apparatus is used in various environments, the toner can form a high-definition image not only in a normal temperature and normal humidity environment but also in a high temperature and high humidity environment, There is a demand for excellent printing durability. Further, when a large number of sheets are continuously printed, it is required that the fluctuation of the line width and the line image density is extremely small. The excellent reproducibility of thin lines is an important index for stably forming a high-definition image.

  Japanese Patent Laid-Open No. 2008-9130 (Patent Document 1) discloses that a specific structure is added to a polymerizable monomer composition containing a polymerizable monomer and a colorant in a toner production method by suspension polymerization. There has been proposed a method for producing a polymerized toner excellent in fine line reproducibility and printing durability by containing a titanate coupling agent.

In the examples of Patent Document 1, the polymerizable monomer composition is polymerized in an aqueous medium containing magnesium hydroxide colloid as a dispersion stabilizer to form core-shell type colored polymer particles, and polymerization is performed. Thereafter, it is shown that sulfuric acid was added to an aqueous dispersion containing colored polymer particles until pH 6 or lower (around pH 6) to solubilize and remove the magnesium hydroxide colloid.
However, the production method of Patent Document 1 requires the use of an expensive titanate coupling agent, and a problem remains in terms of cost reduction.

  JP 2006-276293 A (Patent Document 2) suspends a polymerizable monomer composition containing a specific polyfunctional ester compound in an aqueous medium containing magnesium hydroxide colloid as a dispersion stabilizer. Then, the polymerizable monomer for the shell is polymerized in the presence of the generated colored polymer particles to form core-shell type colored polymer particles, and after the polymerization, the pH is reduced to 6.5 or less. It is described that the poorly water-soluble inorganic compound colloid is solubilized and removed by adjustment.

  JP 2001-183872 A (Patent Document 3) discloses a polymerizable monomer composition containing a specific charge control agent and a fatty acid having 6 to 40 carbon atoms in an aqueous medium containing a dispersion stabilizer. It is described that the toner was obtained by suspension polymerization, removing the dispersant with dilute hydrochloric acid, repeating washing with water and drying, and adding hydrophobic silica.

  Patent Documents 1 to 3 describe that the toners are excellent in storage stability, low-temperature fixability, fine line reproducibility, printing durability under normal temperature and humidity conditions, high image density, and no fogging and voids. However, according to the study by the present inventors, it has been found that any of the fine line reproducibility, the printing durability under a normal temperature and normal humidity environment, and the printing durability under a high temperature and high humidity environment are inferior.

  An electrophotographic image forming apparatus is required to stably form a high-definition image regardless of environmental changes. In order to meet the increasing level of demand for electrostatic charge image developing toners used as developers, static electricity with excellent print durability and fine line reproducibility is not only under normal temperature and humidity conditions, but also in high temperature and high humidity environments. There is a need for toners for developing charge images.

JP 2008-9130 A JP 2006-276293 A JP 2001-183872 A

  An object of the present invention is to provide a toner for developing an electrostatic charge image that has excellent printing durability and fine line reproducibility, and a method for producing the same, even when the printing environment varies greatly from a normal temperature and normal humidity environment to a high temperature and high humidity environment. It is to provide.

  As a result of diligent research to solve the above problems, the inventors of the present invention have significantly improved printing durability and fine line reproducibility by controlling the amount of fatty acid on the surface and inside of the toner within a specific selected range. It has been found that an excellent electrostatic charge image developing toner can be obtained.

  More specifically, the present inventors provide a method for producing a toner for developing an electrostatic image comprising colored polymer particles, comprising a step of obtaining an aqueous dispersion of colored polymer particles containing a dispersion stabilizer by a wet method. 1) Removal of dispersion stabilizer, acid washing, 2) Repeated water washing, 3) Redispersion in water, and then after adding an aqueous solution of fatty acid salt, pH adjustment with acid is performed to normal temperature and humidity It has been found that an electrostatic charge image developing toner can be obtained that is remarkably excellent in printing durability and fine line reproducibility not only in the environment but also in a high temperature and high humidity environment.

  When the surface state of the colored polymer particles constituting the toner for developing an electrostatic charge image of the present invention was analyzed, a surface state different from that of the conventional product was observed. Specifically, the fatty acid amount A when the extract obtained by Soxhlet extraction of the toner is measured with a gas chromatograph mass spectrometer is 50 to 6000 ppm based on the toner, and the toner is Soxhlet extracted after alkali washing. It was found that the amount B of fatty acid when the extract obtained in this way was measured with a gas chromatograph mass spectrometer was less than 50 ppm based on the toner.

  The electrostatic image developing toner of the present invention is an electrostatic image developing toner that has excellent printing durability and fine line reproducibility even when the printing environment fluctuates greatly from a normal temperature and normal humidity environment to a high temperature and high humidity environment. And a manufacturing method thereof.

According to the present invention, in the electrostatic image developing toner comprising colored polymer particles containing a binder resin, a colorant, a charge control agent, and a release agent,
(1) The fatty acid amount A when the extract obtained by Soxhlet extraction of the toner is measured with a gas chromatograph mass spectrometer is 50 to 6000 ppm based on the toner,
(2) Provided is an electrostatic charge image developing toner in which the amount of fatty acid B measured with a gas chromatograph mass spectrometer is less than 50 ppm based on the toner, when the extract obtained by Soxhlet extraction after alkaline washing of the toner is measured. Is done.

According to the present invention, in the method for producing a toner for developing an electrostatic charge image containing colored polymer particles, comprising a step of obtaining an aqueous dispersion of colored polymer particles containing a dispersion stabilizer by a wet method.
(1) A dispersion stabilizer removing step of washing and removing the dispersion stabilizer after obtaining an aqueous dispersion of colored polymer particles,
(2) A water washing step in which after the dispersion stabilizer removing step, dehydration is repeated and dispersed again in water and dehydration is repeated.
(3) The colored polymer particles are separated by filtration after the water washing step, further re-dispersed in water, and a rinsing step in which an aqueous solution of fatty acid salt is added (4) After the rinsing step, an inorganic acid is added to the aqueous dispersion, There is provided a method for producing a toner for developing an electrostatic charge image, in which a pH adjusting step for lowering the pH further when redispersed in water is provided.

  According to the present invention, it is possible to provide a toner for developing an electrostatic charge image that is remarkably excellent in printing durability and fine line reproducibility not only in a normal temperature and normal humidity environment but also in a high temperature and high humidity environment, and a method for producing the same.

1. Method for producing colored polymer particles (polymerized toner):
The colored polymer particles (polymerized toner) constituting the toner for developing an electrostatic image of the present invention can be produced by a wet method such as a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method. A well-known method can be employ | adopted for the method of manufacturing a colored polymer particle by a wet method. In the wet method, it can be produced by obtaining an aqueous dispersion of colored polymer particles containing a dispersion stabilizer, but in an aqueous medium containing the dispersion stabilizer, a polymerizable monomer, a colorant, charge control A suspension polymerization method that can be obtained by a production method including a step of polymerizing a polymerizable monomer composition containing an agent and a release agent is preferred. In the suspension polymerization method, the polymerizable monomer composition is subjected to suspension polymerization, and then the polymerizable monomer for the shell is polymerized in the presence of the generated colored polymer particles to obtain core-shell type colored polymer particles. May be formed. Therefore, the electrostatic image developing toner of the present invention includes those containing core-shell type colored polymer particles.

  In the present invention, it is preferable to use a colloid of a poorly water-soluble metal compound soluble in an acid as a dispersion stabilizer. The charge control agent is preferably a charge control resin, and more preferably a positive charge control resin such as a styrene-acrylate copolymer containing a quaternary ammonium (salt) group. The polymerizable monomer composition is preferably a polyfunctional ester compound of a polyhydric alcohol and a long-chain alkyl fatty acid having 10 to 25 carbon atoms as the release agent.

  In the production method of the present invention, a dispersion stabilizer removing step for removing the dispersion stabilizer from the aqueous dispersion of colored polymer particles obtained by a wet method is arranged. In suspension polymerization, which is a preferred production method, after the polymerization, an acid washing step is performed in which an acid is added to an aqueous dispersion containing the produced colored polymer particles to dissolve the colloid of the inorganic compound. In this acid cleaning step, acid cleaning is performed by adjusting the pH of the aqueous dispersion to less than 6.5 by adding acid. Next, a water washing step of washing the colored polymer particles separated by filtration with water is arranged.

In the present invention, in order to further improve the printing durability and fine line reproducibility, the colored polymer particles filtered off after the water washing step are further redispersed in water, and then the long chain alkyl fatty acid salt having 8 to 24 carbon atoms. A step of rinsing with an aqueous solution is arranged, and then a pH adjusting step of adding an inorganic acid is arranged in order to lower the pH further when redispersed in water. After the colored polymer particles are filtered off, the wet colored polymer particles are dried according to a conventional method.
Hereinafter, the suspension polymerization method which is a preferable production method will be described in detail.

(1) Polymerizable monomer:
A monovinyl monomer is used as the main component of the polymerizable monomer. Examples of the monovinyl monomer include aromatic vinyl monomers such as styrene, vinyltoluene, and α-methylstyrene; (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Such as propyl acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, (meth) acrylamide, etc. Derivatives of (meth) acrylic acid; monoolefin monomers such as ethylene, propylene and butylene;

  Monovinyl monomers may be used alone or in combination of a plurality of monomers. Of these monovinyl monomers, aromatic vinyl monomers alone, combinations of aromatic vinyl monomers and (meth) acrylic acid derivatives, and the like are preferably used.

  When a crosslinkable monomer is used together with a monovinyl monomer, the hot offset property can be improved. A crosslinkable monomer is a monomer having two or more vinyl groups. Specific examples thereof include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; diethylenically unsaturated carboxylic acid esters such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and 1,4-butanediol diacrylate; Compounds other than those having two vinyl groups such as N, N-divinylaniline and divinyl ether; compounds having three or more vinyl groups such as pentaerythritol triallyl ether and trimethylolpropane triacrylate; .

  These crosslinkable monomers can be used alone or in combination of two or more. The amount used is usually 10 parts by weight or less, preferably 0.01 to 7 parts by weight, more preferably 0.05 to 5 parts by weight, particularly preferably 0.1 to 100 parts by weight of the monovinyl monomer. 3 parts by weight.

  Specific examples of macromonomers include polymers obtained by polymerizing styrene, styrene derivatives, methacrylic acid esters, acrylic acid esters, acrylonitrile, methacrylonitrile, etc. alone or in combination of two or more; macromonomers having a polysiloxane skeleton Can be mentioned. Among these, hydrophilic ones are preferable, and a polymer obtained by polymerizing methacrylic acid ester or acrylic acid ester alone or in combination thereof is particularly preferable.

  When the macromonomer is used, the amount used is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.05 to 1 part per 100 parts by weight of the monovinyl monomer. Parts by weight. When the amount of the macromonomer is within the above range, it is preferable because the preservability of the polymerized toner is maintained and the fixing property is improved.

(2) Colorant:
As the colorant, various pigments and dyes used in the field of toner such as carbon black and titanium white can be used. Examples of the black colorant include carbon black and nigrosine-based dyes and pigments; magnetic particles such as cobalt, nickel, iron tetroxide, manganese iron oxide, zinc iron oxide, and nickel iron oxide. When carbon black is used, it is preferable to use carbon black having a primary particle size of 20 to 40 nm because good image quality can be obtained and the safety of the toner to the environment is enhanced. As a color toner colorant, a yellow colorant, a magenta colorant, a cyan colorant, or the like can be used.

  As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds, and the like are used. Specifically, for example, C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 90, 93, 95, 96, 97, 109, 110, 111, 120, 128, 129, 138, 147, 155, 168, 180, 181 and the like. In addition, Nephthol Yellow S, Hansa Yellow G, and C.I. I. Examples include but are not limited to bat yellow.

  Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, for example, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 31, 48, 48: 2, 48: 3, 48: 4, 57, 57: 1, 58, 60, 63, 64, 68, 81, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 166, 169, 170, 177, 184, 185, 187, 202, 206, 207, 209, 220, 251, and 254, but are not limited thereto. As other magenta colorants, C.I. I. And CI pigment violet 19.

  Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like. Specifically, for example, C.I. I. Pigment Blue 1, 2, 3, 6, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17, 60, 62, and 66, but are not limited thereto. Other examples of cyan colorants include phthalocyanine blue, C.I. I. Bat Blue, C.I. I. Acid blue and the like.

  These colorants can be used alone or in combination of two or more. The colorant is usually used in a proportion of 0.1 to 50 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of the polymerizable monomer.

(3) Charge control agent:
In order to improve the chargeability of the polymerized toner, it is preferable to include various positively chargeable or negatively chargeable charge control agents in the polymerizable monomer composition. In the present invention, a charge control resin is used as the charge control agent. Other charge control agents may be used in combination with the charge control resin as necessary.

  The charge control resin includes a negative charge control resin and a positive charge control resin, and the chargeability of the charge control resin is selected depending on whether the toner of the present invention is a negatively chargeable toner or a positively chargeable toner. If necessary, the charge control resin can be used in combination with a positive charge control resin and a negative charge control resin to control the charge characteristics of the polymerized toner.

  Examples of the negative charge control resin include polymers having a substituent such as a carboxyl group or a salt thereof, a phenol group or a salt thereof, a thiophenol group or a salt thereof, a sulfonic acid group or a salt thereof in the polymer side chain.

  Among these, a copolymer of a monovinyl monomer containing a sulfonic acid group or a salt thereof in the polymer side chain and another monovinyl monomer copolymerizable with the monovinyl monomer is preferable. Examples of other monovinyl monomers that can be copolymerized include ethylenically unsaturated carboxylic acid ester monomers, aromatic vinyl monomers, and ethylenically unsaturated nitrile monomers. Monovinyl monomers containing sulfonic acid groups or salts thereof include styrene sulfonic acid, sodium styrene sulfonate, potassium styrene sulfonate, 2-acrylamido-2-methylpropane sulfonic acid, sodium vinyl sulfonate, ammonium methacryl sulfonate. Etc.

  The copolymerization ratio of the monovinyl monomer having a functional group such as a sulfonic acid group or a salt thereof is usually 0.5 to 15% by weight, preferably 1 to 10% by weight. The weight average molecular weight of the negative charge control resin is usually 2,000 to 50,000, preferably 4,000 to 40,000. The glass transition temperature of the negative charge control resin is usually 40 to 80 ° C., preferably 45 to 75 ° C.

Examples of the positive charge control resin include amino such as —NH ₂ , —NHCH ₃ , —N (CH ₃ ) ₂ , —NHC ₂ H ₅ , —N (C ₂ H ₅ ) ₂ , —NHC ₂ H ₄ OH. Examples thereof include a polymer containing a group and a polymer in which these amino groups are ammonium chlorided. The positive charge control resin is obtained by copolymerizing a monovinyl monomer containing an amino group and another monovinyl monomer copolymerizable with the monovinyl monomer. It can be obtained by ammonium chloride.

  Examples of monovinyl monomers containing amino groups include alkyl (meth) such as acrylamide, methacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N-ethylacrylamide, and N-ethylmethacrylamide. Acrylamide monomer; (meth) acrylic acid derivatives such as 3- (dimethylamino) propyl acrylate and 3- (dimethylamino) propyl methacrylate; allylamine; styrene derivatives such as 2-aminostyrene and 4-aminostyrene; Is mentioned.

  The copolymerization ratio of the monovinyl monomer having a functional group such as amino group or ammonium base is usually 0.5 to 15% by weight, preferably 1 to 10% by weight. The weight average molecular weight of the positive charge control resin is usually 2,000 to 30,000, preferably 4,000 to 25,000. The glass transition temperature of the positive charge control resin is usually 40 to 100 ° C., preferably 45 to 80 ° C.

  The charge control resin is preferably a positive charge control resin such as a quaternary ammonium (salt) group-containing styrene-acrylate copolymer.

  The charge control resin is usually used in a proportion of 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the polymerizable monomer. When the content of the charge control resin is too large, the charge amount increases too much, and the toner scatters at the time of development and transfer, and the fluidity of the toner deteriorates. When the content of the charge control resin is too small, the charge amount is lowered, and printing stains are liable to occur.

(4) Release agent:
As a mold release agent, a polyfunctional ester compound of a polyhydric alcohol and a long-chain alkyl fatty acid having 10 to 25 carbon atoms is used. Examples of the polyhydric alcohol include polyglycerin, pentaerythritol, dipentaerythritol and the like. The carbon number of the long-chain alkyl fatty acid is preferably 13-24. Examples of the long chain alkyl carboxylic acid include myristic acid, palmitic acid, lauric acid, and the like.

  Specific examples of the polyfunctional ester compound include, for example, polyglycerin such as triglycerin pentabehenate, tetraglycerin hexabehenate, pentaglycerin heptabehenate, hexaglycerin octastearate, hexaglycerin octabehenate and the like. Esters with long-chain alkyl fatty acids; esters of pentaerythritol and long-chain alkyl fatty acids such as pentaerythritol tetramyristate, pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, pentaerythritol tetralaurate; dipentaerythritol hexamyristate , Esters of dipentaerythritol and long-chain alkyl fatty acids such as dipentaerythritol hexapalmitate and dipentaerythritol hexalaurate; It is below. These polyfunctional ester compounds can be used alone or in combination of two or more.

  The use ratio of the polyfunctional ester compound is usually 3 to 15 parts by weight, preferably 4 to 13 parts by weight, and more preferably 5 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer. If the amount of the polyfunctional ester compound used is too large, the increase of the polyfunctional ester compound in the vicinity of the toner surface deteriorates the toner surface state, and the external additive is buried or fogging occurs. When there is too much usage-amount of a polyfunctional ester compound, blocking resistance (preservation property) will also worsen.

  If the amount of the polyfunctional ester compound used is too small, the releasability of the toner is deteriorated at the time of fixing, and the toner surface state is not appropriately modified, and the toner printing durability and fine line reproducibility cannot be improved. Or it is on a downward trend.

(5) Polymerization initiator:
Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis [2-methyl-N- (2- Hydroxyethyl) propionamide], 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile Azo compounds such as: di-t-butyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexano Ate, t-butyl peroxypivalate, di-isopropyl peroxydicarbonate, di-t-butyl peroxyisophthalate, 1 Peroxides such as 1 ', 3,3'-tetramethylbutylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy-2-ethylbutanoate, and the like; Etc. A redox initiator in which these polymerization initiators and a reducing agent are combined can also be used.

  Among these initiators, it is usually preferable to select an oil-soluble polymerization initiator that is soluble in the polymerizable monomer, and a water-soluble polymerization initiator can be used in combination as necessary.

  As the polymerization initiator, an organic peroxide having a molecular weight of 90 to 205 and a purity of 90% or more is preferable. The molecular weight of the polymerization initiator is more preferably 170 to 200, still more preferably 175 to 195. The purity of the polymerization initiator represents the weight percent of the main component polymerization initiator, preferably 92% or more, and more preferably 95% or more.

  The one-hour half-life temperature of the organic peroxide is preferably 70 to 95 ° C., more preferably 75 to 95 ° C., and 85 to 95 ° C., because a toner having good printing durability can be obtained. Further preferred. The half-life temperature is an index representing the ease of cleavage of the polymerization initiator. When the polymerization initiator is held at a certain temperature, it decomposes and becomes half the original initiator amount after a certain time. Temperature. For example, at a one-hour half-life temperature, this constant time is a half-life temperature of one hour.

  By using a polymerization initiator having a preferred one-hour half-life temperature, the amount of unreacted polymerizable monomer remaining in the resulting polymer particles and the amount of by-products such as ether components by-produced by the polymerization initiator can be reduced. Can be reduced. As a result, it is possible to obtain a toner that has excellent high temperature storage stability, does not generate bad odor during printing, does not deteriorate the surrounding environment, and has excellent printing durability.

  As the organic peroxide of the polymerization initiator, a peroxyester is preferred because it has a particularly high initiation efficiency and the amount of residual monomer can be reduced, and a non-aromatic peroxyester (that is, a peroxyester having no aromatic ring). Oxyester) is more preferred.

  The polymerization initiator is usually used in a proportion of 0.1 to 20 parts by weight, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer. It is done.

  The polymerization initiator can be added in advance to the polymerizable monomer composition, but in order to suppress premature polymerization, after completion of the droplet forming step of the polymerizable monomer composition or during the polymerization reaction It can also be added directly to the suspension.

(6) Molecular weight regulator:
In the polymerization, a molecular weight modifier is preferably used. Examples of molecular weight modifiers include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, 2,2,4,6,6-pentamethylheptane-4-thiol; tetramethylthiuram disulfide, And thiurams such as tetraethylthiuram disulfide; The molecular weight modifier is usually contained in the polymerizable monomer composition before the start of polymerization, but can also be added during the polymerization. The molecular weight modifier is usually used in a proportion of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, with respect to 100 parts by weight of the polymerizable monomer. If the amount of the molecular weight modifier used is too small, the effect of adjusting the molecular weight cannot be obtained, and if it is too large, the amount of residual monomer and residual VOC increases.

(7) Dispersion stabilizer:
Polymerization of the polymerizable monomer composition is performed in an aqueous medium containing a dispersion stabilizer. As the aqueous medium, water such as ion exchange water is generally used, but a small amount of an organic solvent compatible with water such as alcohols may be used in combination as necessary.

  As the dispersion stabilizer, it is preferable to use a colloid of a poorly water-soluble metal compound. The colloid of a hardly water-soluble metal compound can be suitably prepared by a method in which a polyvalent metal salt and a monovalent metal compound are reacted in an aqueous medium.

  Examples of the polyvalent metal salt include halogenated salts such as magnesium, aluminum, calcium, manganese, iron, nickel, copper, and tin, sulfates, nitrates, acetates, and the like. More specifically, as polyvalent metal salts, magnesium salts such as magnesium chloride, magnesium sulfate, magnesium nitrate and magnesium acetate; aluminum salts such as aluminum chloride, aluminum sulfate, aluminum nitrate and aluminum acetate; calcium chloride, calcium sulfate and nitric acid And calcium salts such as calcium and calcium acetate. These polyvalent metal salts can be used alone or in combination of two or more.

  The monovalent metal compound is a salt or hydroxide of a monovalent metal with an anion selected from phosphate ion, hydrogen phosphate ion, carbonate ion and hydroxide ion. The monovalent metal of the monovalent metal compound is preferably at least one monovalent metal selected from the group consisting of lithium, sodium and potassium. Specific examples of the monovalent metal compound include hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; phosphates such as lithium phosphate, sodium phosphate, and potassium phosphate; lithium carbonate, Examples thereof include carbonates such as sodium carbonate and potassium carbonate. Among these, hydroxides are preferable. Monovalent metal compounds can be used alone or in combination of two or more.

  The colloid of the poorly water-soluble metal compound is not limited by its production method, but is preferably a poorly water-soluble metal hydroxide colloid obtained by adjusting the pH of the aqueous solution of the water-soluble polyvalent metal compound to 7 or more. A colloid of a hardly water-soluble metal hydroxide produced by a reaction of a water-soluble polyvalent metal compound and an alkali metal hydroxide in an aqueous phase is more preferable. As such a poorly water-soluble metal compound colloid, a magnesium hydroxide colloid is preferable.

  The dispersion stabilizer is generally used at a ratio of 0.1 to 20 parts by weight with respect to 100 parts by weight of the polymerizable monomer. When the proportion of the dispersion stabilizer is too small, it is difficult to obtain sufficient polymerization stability, and polymerized aggregates are easily generated. On the other hand, when the proportion of the dispersion stabilizer is too large, the viscosity of the aqueous solution increases and the polymerization stability decreases. In the present invention, if necessary, other dispersion stabilizers may be used in combination.

(8) Polymerization step:
In the polymerized toner, a binder resin produced by polymerization of a polymerizable monomer becomes colored polymer particles, and a colored polymer in which additive components such as a colorant, a charge control resin, and a polyfunctional ester compound are dispersed. Particles. A core-shell type colored polymer particle can be obtained by forming the colored polymer particle as a core and forming a shell composed of a polymer layer thereon.

  The polymerized toner by the suspension polymerization method can be obtained, for example, by the following steps. A polymerizable monomer, a colorant, a charge control resin, a polyfunctional ester compound, and other additives are mixed using a mixer, and if necessary, a media type wet pulverizer (for example, a bead mill) is used. Use and wet pulverize to prepare a polymerizable monomer composition. Next, the polymerizable monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer and stirred to form uniform droplets of the polymerizable monomer composition (volume average particle diameter is 50 to 1). , Primary droplets of about 1,000 μm). In order to avoid premature polymerization, the polymerization initiator is preferably added to the aqueous dispersion medium after the size of the droplets becomes uniform in the aqueous dispersion medium.

  A polymerization initiator is added to and mixed with the suspension in which the droplets of the polymerizable monomer composition are dispersed in an aqueous dispersion medium, and the particle size of the droplets is determined using a high-speed rotary shearing stirrer. Stir until the particle size is close to the polymerized toner particles. A suspension containing fine droplets (secondary droplets having a volume average particle diameter of about 1 to 12 μm) formed in this manner is charged into a polymerization reactor, usually 5 to 120 ° C., preferably Suspension polymerization is performed at a temperature of 35 to 95 ° C. If the polymerization temperature is too low, a polymerization initiator having a high catalytic activity must be used, which makes it difficult to manage the polymerization reaction. If the polymerization temperature is too high, when an additive that melts at a low temperature is included, this may bleed on the surface of the polymerized toner, resulting in poor storage stability.

  The volume average particle size and particle size distribution of the fine droplets of the polymerizable monomer composition affect the volume average particle size and particle size distribution of the polymerized toner. When the particle size of the droplet is too large, the generated polymer toner particles become too large, and the resolution of the image is lowered. If the particle size distribution of the droplets is wide, the fixing temperature varies, causing problems such as fogging and toner filming. The droplets of the polymerizable monomer composition are desirably formed so as to be approximately the same size as the colored polymer particles to be produced.

  The volume average particle diameter of the droplets of the polymerizable monomer composition is usually 1 to 12 μm, preferably 2 to 10 μm, more preferably 3 to 9 μm. In order to obtain a high-definition image, it is desirable to reduce the volume average particle size of the droplets, particularly when a polymerized toner having a small particle size is used. The particle size distribution (volume average particle size / number average particle size) of the droplets of the polymerizable monomer composition is usually 1 to 3, preferably 1 to 2.5, and more preferably 1 to 2. In particular, when forming fine droplets, an aqueous dispersion medium containing a monomer composition is placed in a gap between a rotor that rotates at high speed and a stator that surrounds the rotor and has small holes or comb teeth. A distribution method is preferred.

  One or more of the above-mentioned monovinyl monomers are selected as the polymerizable monomer. To lower the fixing temperature of the toner, the glass transition temperature (Tg) is usually 80 ° C. or lower, preferably 40 to 80 ° C. More preferably, it is preferable to select a polymerizable monomer or a combination of polymerizable monomers capable of forming a polymer at 50 to 70 ° C. In the present invention, when the binder resin constituting the binder resin is a copolymer, the Tg is a calculated value (referred to as “calculated Tg”) calculated according to the type and use ratio of the polymerizable monomer to be used. ).

  Suspension polymerization produces colored polymer particles in which an additive component such as a colorant is dispersed in a polymer of a polymerizable monomer. A polymer layer is further formed on the colored polymer particles obtained by suspension polymerization for the purpose of improving the storage stability (blocking resistance), low-temperature fixability, meltability during fixing, etc. of the polymerized toner. And a capsule toner having a core-shell type structure.

  As a method for forming a core-shell type structure, the colored polymer particles are used as core particles, and a polymerizable monomer for shell is further polymerized in the presence of the core particles, and a polymer layer is formed on the surface of the core particles. A method of forming (shell) is employed. When a polymer that forms a polymer having a Tg higher than that of the binder resin constituting the core particle is used as the polymerizable monomer for the shell, the storage stability (blocking resistance) of the polymerized toner can be improved. it can. On the other hand, by setting the Tg of the binder resin constituting the core particles low, the fixing temperature of the toner can be lowered or the melting characteristics can be improved. Therefore, by forming the core-shell type colored polymer particles in the polymerization step, a polymerized toner that can cope with high-speed printing, full color, OHP (overhead projector) permeability, and the like can be obtained.

  As a polymerizable monomer for forming a core and a shell, a preferable thing can be suitably selected from the above-mentioned monovinyl monomers. The weight ratio of the polymerizable monomer for the core and the polymerizable monomer for the shell is usually 40/60 to 99.9 / 0.1, preferably 60/40 to 99.7 / 0.3, more preferably Is 80 / 20-99.5 / 0.5. If the ratio of the polymerizable monomer for the shell is too small, the effect of improving the storage stability of the polymerized toner is small, and if it is excessive, the effect of reducing the fixing temperature is small.

  The Tg of the polymer formed by the shell polymerizable monomer is usually 50 to 120 ° C, preferably 60 to 110 ° C, more preferably 80 to 105 ° C. The difference in Tg between the polymer formed from the core polymerizable monomer and the polymer formed from the shell polymerizable monomer is preferably 10 ° C. or higher, more preferably 20 ° C. or higher, particularly Preferably it is 30 degreeC or more. In many cases, from the viewpoint of the balance between the fixing temperature and the storage stability, a core polymerizable monomer that can form a polymer having a Tg of usually 60 ° C. or lower, preferably 40 to 60 ° C. is selected. Is preferred. On the other hand, as the polymerizable monomer for the shell, it is preferable to use a monomer that forms a polymer having a Tg exceeding 80 ° C. such as styrene or methyl methacrylate, either alone or in combination of two or more. .

  The polymerizable monomer for shell is preferably added to the polymerization reaction system as droplets smaller than the average particle diameter of the core particles. When the particle size of the shell polymerizable monomer droplets is too large, it is difficult to form a polymer layer uniformly around the core particles. In order to make the polymerizable monomer for the shell into small droplets, the mixture of the polymerizable monomer for the shell and the aqueous dispersion medium is finely dispersed using, for example, an ultrasonic emulsifier. What is necessary is just to add the obtained dispersion liquid to a polymerization reaction system.

  When the polymerizable monomer for shell is a relatively water-soluble monomer (for example, methyl methacrylate) having a solubility in water at 20 ° C. of 0.1% by weight or more, Since it is easy to move quickly, it is not necessary to carry out fine dispersion treatment, but it is preferable to carry out fine dispersion treatment in order to form a uniform shell. When the polymerizable monomer for shell is a monomer having a solubility in water at 20 ° C. of less than 0.1% by weight (for example, styrene), it is subjected to fine dispersion treatment or solubility in water at 20 ° C. Is preferably added to the reaction system by adding 5% by weight or more of an organic solvent (for example, alcohols) to the reaction system.

  A charge control agent can be added to the polymerizable monomer for shell. As the charge control agent, the same charge control resin as that used in the core particle production described above is preferable. When used, the charge control agent is usually 0.01 to 10 parts per 100 parts by weight of the polymerizable monomer for shell. Part by weight, preferably 0.1 to 5 parts by weight is used.

  In order to produce a core-shell type polymerized toner, a shell polymerizable monomer or an aqueous dispersion thereof is added all at once or continuously or intermittently to a suspension containing core particles. To do. When adding the shell polymerizable monomer, it is preferable to add a water-soluble polymerization initiator in order to efficiently form the shell. If a water-soluble polymerization initiator is added at the time of addition of the shell polymerizable monomer, the water-soluble polymerization initiator enters the vicinity of the outer surface of the core particle to which the shell polymerizable monomer has migrated, and the core monomer surface is overlapped. It is considered that the combined layer is easily formed.

  Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis- Examples include azo initiators such as [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide]. The amount of the water-soluble polymerization initiator used is usually 0.1 to 50 parts by weight, preferably 1 to 20 parts by weight per 100 parts by weight of the polymerizable monomer for shell.

  The average thickness of the shell is usually 0.001 to 1.0 μm, preferably 0.003 to 0.5 μm, and more preferably 0.005 to 0.2 μm. When the shell thickness is too large, the fixing property of the polymerized toner is lowered, and when it is too small, the storage property of the polymerized toner is lowered. When the core particle diameter and shell thickness of the polymerized toner can be observed with an electron microscope, it can be obtained by directly measuring the particle size and shell thickness randomly selected from the observation photograph. When it is difficult to observe the core and the shell, it can be calculated from the particle size of the core particle and the amount of the polymerizable monomer that forms the shell.

 An aqueous dispersion containing colored polymer particles or core-shell colored polymer particles is obtained by the production process of polymer particles. The aqueous dispersion is used as it is, or ion-exchanged water or the like is added to adjust the concentration of the colored polymer particles to obtain an aqueous dispersion containing the colored polymer particles. Then, if necessary, the aqueous dispersion can be stripped to remove volatile organic components including unreacted polymerizable monomers remaining in the colored polymer particles.

2. Post-processing process:
(1) Dispersion stabilizer removal step (acid washing step):
In suspension polymerization, acid washing as a dispersion stabilizer removal step is performed to dissolve and remove the colloid of the poorly water-soluble metal compound used as the dispersion stabilizer present on the surface of the colored polymer particles that have undergone the polymerization step. A process is provided. The colloid of a poorly water-soluble metal compound used as a dispersion stabilizer surrounds the droplets of the polymerizable monomer composition in an aqueous medium and plays a role of stabilizing the droplets. After the polymerization, the colloid of the poorly water-soluble metal compound is attached to the surface of the colored polymer particles. From the viewpoint of toner characteristics, it is necessary to remove the colloid of the poorly water-soluble metal compound adhering to the surface of the colored polymer particles.

Since the colloid of a hardly water-soluble metal compound is dissolved by adding an acid to an aqueous dispersion containing colored polymer particles and adjusting the pH to an acidic region, an acid washing step is arranged. In general, the acid washing step is carried out by adding an acid to an aqueous dispersion containing colored polymer particles produced by polymerization so that the pH of the aqueous dispersion is 6.5 or lower. The pH of the aqueous dispersion is preferably 4 to 6.5, more preferably 4.5 to 6.
As the acid that can be used, inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as acetic acid, citric acid, and oxalic acid can be used, but inorganic acids that can adjust pH with a small amount of addition are preferable. Of the inorganic acids, sulfuric acid is particularly preferable.

  The acid washing step is desirably performed after cooling the aqueous dispersion containing colored polymer particles generated by polymerization to about 25 ° C. after performing a stripping step if desired. Acid washing can be performed by adding acid to an aqueous dispersion containing colored polymer particles and adjusting the pH, followed by stirring for about 5 to 30 minutes.

(2) Water washing process:
After the acid washing, the aqueous dispersion containing the colored polymer particles is filtered to separate the colored polymer particles. Then, ion-exchange water is newly added to the colored polymer particles, and the colored polymer particles are purified by performing a washing operation such as redispersion in water (reslurry step), filtration and dehydration again.

  This filtration dehydration and reslurry process may be repeated several times as necessary, but 2 to 3 times are preferable from the viewpoint of efficiency. You may perform the washing | cleaning process by water continuously by the method of spraying water on the wet cake of colored polymer particle | grains using the belt conveyor which has arrange | positioned the filter cloth.

(3) Rinsing process:
It is possible to arrange a rinsing step of filtering the colored polymer particles after the water washing step, redispersing in water, and adding an aqueous solution of fatty acid salt to the aqueous dispersion containing the redispersed colored polymer particles. This is desirable for further improvement. Fatty acid salts include fatty acid metal salts and fatty acid ammonium salts, but fatty acid metal salts are preferred from the viewpoint of solubility in water. The fatty acid constituting the fatty acid metal salt may be saturated or unsaturated, and may be linear or branched. As the fatty acid, a saturated fatty acid is preferable, and a linear saturated fatty acid is more preferable. The fatty acid may have a substituent such as a hydroxyl group, an aldehyde group, or an epoxy group in its structure.
The aqueous solution concentration of the fatty acid salt is usually 0.5 to 20% by weight, preferably 1 to 10% by weight, more preferably 2 to 5% by weight, from the viewpoint of the solubility of the fatty acid salt. When the fatty acid salt is difficult to dissolve in water, it is possible to increase the solubility by increasing the temperature of the dissolved water or by making the dissolved water alkaline.

  Examples of fatty acids include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, epoxy stearic acid, oleic acid, linoleic acid, linolenic acid, hydroxystearic acid, arachidic acid, Examples include behenic acid, erucic acid, lignoceric acid, serotic acid, montanic acid, and melissic acid. Among these, saturated fatty acids having 8 to 24 carbon atoms are preferable, saturated fatty acids having 10 to 18 carbon atoms are more preferable, and 12 to 14 carbon atoms are still more preferable. These fatty acids can be used alone or in combination of two or more. If the carbon number of the fatty acid is too large, the toner surface may become sticky and the fluidity of the toner may decrease. Conversely, if the carbon number of the fatty acid is too small, the toner surface becomes hydrophilic and the charge amount decreases. There is.

  Examples of the metal constituting the fatty acid metal salt include alkali metals such as lithium, potassium and sodium; alkaline earth metals such as beryllium, magnesium, calcium and barium; titanium, zinc, iron, silver, zirconium, copper, aluminum and nickel Can be mentioned. These metals can be used alone or in combination of two or more. Among these, alkali metals are preferable.

(4) pH adjustment step:
In the present invention, acid treatment is performed after the rinsing treatment. By adjusting the pH by this acid treatment, the fatty acid metal salt used in the rinse treatment precipitates in the system and adheres to the surface of the colored polymer particles. Normally, it was thought that when a hydrophilic compound such as a fatty acid adheres to the surface of the colored polymer particles, the moisture in the air is adsorbed and the durability deteriorates. It was revealed by the present invention that a toner excellent in printing durability and fine line reproducibility can be obtained even in a high humidity environment.
The pH of the acid treatment may be lower than the pH when the colored polymer particles are filtered off after the water washing step and further redispersed in water, and is usually 2 to 6.5, preferably 2.5 to 6, more preferably 3-5.

  As the acid that can be used, those that can be used in the acid treatment step (1) can be used as they are, but among them, inorganic acids are preferable, and sulfuric acid is particularly preferable among inorganic acids.

(5) Drying:
The colored polymer particles after the acid treatment are separated by filtration to obtain wet colored polymer particles. The wet colored polymer particles are dried according to a conventional method.

  In the drying step after washing or rinsing, it is preferable to employ a method in which the wet cake of wet colored polymer particles is dried by introducing a hot gas using a drier having a stirring tank, a rotating blade, or the like.

3. Toner for electrostatic image development:
The colored polymer particles (polymerized toner) obtained by the above production method have a polymerization conversion rate of the polymerizable monomer of almost 100%, and the shell layer has a very thin thickness. The content ratio of additive components such as a charge control resin and a polyfunctional ester compound is substantially the same as their content ratio in the polymerizable monomer composition.

  The volume average particle size of the toner for developing an electrostatic charge image of the present invention (colored polymer particles; including colored polymer particles having a core-shell type structure) is usually 5 to 11 μm, preferably 7 to 10 μm. If the volume average particle diameter of the toner is too large, fine line reproducibility is deteriorated, or the charge amount is lowered and the adhesion is reduced. As a result, toner scattering and fogging occur. When the volume average particle size of the toner is too small, the charge amount increases, but the particle size is small and light and the toner is scattered.

  The particle size distribution represented by the volume average particle size (Dv) / number average particle size (Dp) of the toner of the present invention is usually 1 to 1.3, preferably 1 to 1.2. If the particle size distribution is too large, the charge amount of each toner becomes non-uniform, and the low-charge toner tends to scatter.

The average circularity of the toner of the present invention is usually 0.95 or more, preferably 0.97 or more. The average circularity can be obtained by a ratio (L ₁ / L ₂ ) between the circumferential length L _{1 of the} circle equal to the projected area of the particle and the circumferential length L ₂ of the projected particle image. The average circularity can be measured using a flow type particle image analyzer. When the average circularity is too small, the force of the electric field is not transmitted uniformly during development, and toner is scattered, fogging occurs, and fine line reproducibility is deteriorated. The upper limit value of the average circularity is 1.00.

  In the toner of the present invention, the amount A of fatty acid when an extract obtained by Soxhlet extraction of the toner is measured with a gas chromatograph mass spectrometer is 50 to 6000 ppm, preferably 100 to 5000 ppm, more preferably based on the toner. The amount of fatty acid B is less than 50 ppm, preferably less than 20 ppm based on the toner when the extract obtained by Soxhlet extraction after alkali washing of the toner is 500 to 4000 ppm and measured with a gas chromatograph mass spectrometer. More preferably, it is less than 5 ppm. Since it is difficult to measure the amount of fatty acid as it is, it is preferable to indirectly measure the amount of fatty acid by using a derivative such as esterification.

  In the present invention, the alkali treatment refers to dissolving and removing the fatty acid adhering to the toner particle surface. The toner to be subjected to the alkali treatment is not a Soxhlet extracted toner but a separately weighed toner. Here, the amount A of fatty acid extracted by Soxhlet without alkali treatment indicates the fatty acid present on the surface and inside of the toner particles, and the amount of fatty acid B extracted by Soxhlet after alkali treatment is determined inside the toner particles. The fatty acid which exists in is shown. From the difference between the fatty acid A and the fatty acid amount B, the amount of fatty acid on the surface of the toner particles can be determined.

  The alkali used for the alkali treatment is not particularly limited as long as it dissolves a fatty acid. Examples of the alkali include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkaline earth metal hydroxides such as barium hydroxide and potassium hydroxide; ammonia, amines, and the like. It is done. Among these, alkali metal hydroxides are preferable, and sodium hydroxide and potassium hydroxide are preferable.

The amount of alkali used is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, and more preferably 1 to 3 parts by weight with respect to 100 parts by weight of the toner.
The alkali treatment is performed by dispersing the toner in an aqueous alkali solution, and the concentration of the aqueous alkali solution is usually 0.05 to 3% by weight, preferably 0.1 to 2% by weight. Moreover, although this alkali treatment may be performed once, it is preferably performed 2-3 times in order to increase the effect of removing fatty acids.

 The analysis of fatty acids can be performed by the method described later. GCMS-QP2010 (manufactured by Shimadzu Corporation), JMS-Q1000GC MkII (manufactured by JEOL Ltd.), 7890A (manufactured by Agilent), 6890N (Agilent) Can be used.

  The toner of the present invention can be used as a toner component of various developers, but is preferably used as a nonmagnetic one-component developer. When the toner of the present invention is a non-magnetic one-component developer, an external additive can be mixed as necessary. Examples of the external additive include inorganic particles and organic resin particles that act as a fluidizing agent and an abrasive.

  Examples of the inorganic particles include silicon dioxide (silica), aluminum oxide (alumina), titanium oxide, zinc oxide, tin oxide, barium titanate, strontium titanate, and the like. As organic resin particles, methacrylic acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, styrene-acrylic acid ester copolymer particles, a core is a styrene polymer, and a shell is methacrylic acid. Examples thereof include core-shell type particles formed of an ester copolymer.

  Among these, inorganic oxide particles are preferable, and silicon dioxide is particularly preferable. The surface of the inorganic fine particles can be hydrophobized, and silicon dioxide particles that have been hydrophobized are particularly suitable. Two or more types of external additives may be used in combination. In the case of using a combination of external additives, a method of combining inorganic particles having different average particle sizes or a combination of inorganic particles and organic resin particles is preferable. . The amount of the external additive is not particularly limited, but is usually 0.1 to 6 parts by weight with respect to 100 parts by weight of the polymerized toner. In order to attach the external additive to the polymerized toner, the polymerized toner and the external additive are usually placed in a mixer such as a Henschel mixer and stirred.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited only to these examples. In the following examples and comparative examples, “parts”, “ppm”, and “%” are based on weight unless otherwise specified. The measuring method and evaluation method of various physical properties and characteristics are as follows.

(1) Volume average particle size and particle size distribution:
The particle size distribution represented by the volume average particle size (Dv) and the ratio of the volume average particle size to the number average particle size (Dp) (Dv / Dp) of the colored polymer particles is calculated as follows.
About 0.1 g of a measurement sample (colored polymer particles) was weighed and taken in a beaker, and 0.1 ml of an alkylbenzenesulfonic acid aqueous solution (manufactured by Fuji Film Co., Ltd., trade name: Drywell) was added as a dispersant. Add 10-30 mL of Isoton II to the beaker and disperse with a 20 W ultrasonic disperser for 3 minutes. Then, use a particle size analyzer (trade name: Multisizer, manufactured by Beckman Coulter, Inc.) to determine the aperture diameter. The volume average particle diameter (Dv) and the number average particle diameter (Dp) of the colored resin particles were measured under the conditions of 100 μm, medium; Isoton II, number of measured particles; 100,000 particles, and the particle size distribution (Dv / Dp) was calculated.

(2) Average circularity:
The average circularity of the colored polymer particles is a value measured in a water dispersion system using a flow type particle image analyzer “FPIA-2100” manufactured by Sysmex Corporation. 10 ml of ion-exchanged water is put in a container in advance, and a surfactant (alkylbenzene sulfonate) is added as a dispersant therein, and then 0.02 g of a sample is added and dispersed uniformly. Dispersion processing was performed using an ultrasonic disperser as the dispersing means under conditions of an output of 60 W and a processing time of 3 minutes. The concentration of the colored polymer particles at the time of measurement was adjusted to 3,000 to 10,000 particles / μl. The circularity of 1,000 to 10,000 colored polymer particles (peripheral length of a circle equal to the projected area of the particle / perimeter of the projected particle image) was measured. Using this data, the average circularity was determined.

(3) Fatty acid amount A
About 10 g of the colored polymer particles were precisely weighed, and Soxhlet extraction was performed for 8 hours using methanol. Methanol was added to the extract and transferred to a 10 ml volumetric flask. Hydrochloric acid was added to the volumetric flask to make it acidic, and then phenolphthalein and tetramethylammonium hydroxide as a methylating agent were added and weighed to 10 ml. Using the adjusted solution as a test solution, gas chromatograph mass spectrometry was performed to calculate the amount of fatty acid. This fatty acid amount was defined as fatty acid amount A.
GC-MS measurement conditions Gas chromatograph: Agilent 6890N
Mass spectrometer: Agilent 5973 inert
Column: DB1701 0.25 mm × 30 m df = 1.0 μm
Column temperature: 100 ° C. → 280 ° C. (10 ° C./min)
Injection temperature: 320 ° C
Split ratio: 50: 1
Injection volume: 1 μl
Helium flow rate: 1 ml / min Detector: MSD

(4) Fatty acid amount B
100 parts of colored polymer resin particles were dispersed in 500 parts of a 0.5% aqueous sodium hydroxide solution. After dehydrating by filtration, 500 parts of 0.5% aqueous sodium hydroxide solution was added to reslurry. Thereafter, similarly, dehydration by filtration and reslurrying by adding a sodium hydroxide aqueous solution were repeated three times. After filtration, it was dried to obtain dried colored polymer particles. About the obtained colored polymer particle | grains, the amount of fatty acids was measured by the method shown in (3). This fatty acid amount was defined as fatty acid amount B.

(5) Image quality evaluation of toner (5-1) Printing durability (N / N environment, H / H environment)
Using a commercially available non-magnetic one-component developing type printer (printing speed: A4 size 20 sheets / min), printing paper was set and toner was put in the developing device. After being left for 24 hours in a normal temperature and normal humidity (N / N) environment at a temperature of 23 ° C. and a humidity of 50%, continuous printing was performed up to 12,000 sheets at a 1% printing density in the same environment. Black solid printing (printing density 100%) was performed every 500 sheets, and the printing density of the black solid image was measured using a reflective image densitometer (trade name: RD918, manufactured by Macbeth). After that, white solid printing (printing density 0%) is performed, the printer is stopped in the middle of white solid printing, and the toner in the non-image area on the developed photoreceptor is covered with an adhesive tape (manufactured by Sumitomo 3M Limited, product Name: Scotch mending tape 810-3-18), and then peeled off and affixed to printing paper. Next, the whiteness (B) of the printing paper on which the adhesive tape is affixed is measured with a whiteness meter (trade name: NDW-1D, manufactured by Nippon Denshoku Co., Ltd.). The whiteness (A) was measured and the whiteness difference (B−A) was defined as the fog value. Smaller values indicate better fogging. The number of continuously printed sheets capable of maintaining an image quality with a print density of 1.3 or more and a fog value of 3 or less was counted.
A similar printing durability test was also performed in a high temperature and high humidity environment at a temperature of 32 ° C. and a humidity of 80%. In Table 1, “12,000 <” indicates that the image quality with the print density of 1.3 or more and the fog value of 3 or less could be maintained even at the time of 12,000 sheets. .

(5-2) Fine line reproducibility (under N / N environment)
Using a commercially available non-magnetic one-component developing type printer (printing speed: A4 size 20 sheets / minute), printing paper was set, and toner was put in the developing device. After standing for 24 hours in a normal temperature and normal humidity (N / N) environment at a temperature of 23 ° C. and a humidity of 50%, a line image is continuously formed with 2 × 2 dot lines (width of about 85 μm) in the same environment. Then, continuous printing was performed up to 12,000 sheets.
For every 500 sheets, density distribution data of line images was collected using a printing evaluation system (trade name: RT2000, manufactured by YA-MA).
Based on the density distribution data of the collected line image, the line width is the full width of the line image at the maximum half value of the density, and the line width formed on the first sheet of print paper is used as a reference. The number of continuously printed sheets capable of maintaining the difference at 10 μm or less was examined. In Table 1, “12,000 <” indicates that the line width difference could be maintained at 10 μm or less even at the time of 12,000 sheets.

Example 1
83 parts of styrene and 17 parts of n-butyl acrylate as a monovinyl monomer, 7 parts of carbon black (trade name: # 25B, manufactured by Mitsubishi Chemical Corporation) as a black colorant, a positively chargeable charge control agent (styrene / acrylic resin, 1 part by Fujikura Kasei Co., Ltd., trade name: FCA-207P), 0.6 part divinylbenzene as a crosslinkable monomer, 1.9 parts t-dodecyl mercaptan as a molecular weight regulator, and polymethacrylate macro as a macromonomer After stirring and mixing with a stirrer, 0.25 part of a monomer (manufactured by Toa Gosei Co., Ltd., trade name: AA6) was further uniformly dispersed by a media type dispersing machine. Here, 5 parts of dipentaerythritol hexamyristate was added, mixed and dissolved as a release agent to obtain a polymerizable monomer composition.

  On the other hand, at room temperature, an aqueous solution obtained by dissolving 10.2 parts of magnesium chloride in 250 parts of ion-exchanged water and an aqueous solution prepared by dissolving 6.2 parts of sodium hydroxide in 50 parts of ion-exchanged water were gradually added with stirring. A dispersion of magnesium hydroxide colloid was prepared.

  The polymerizable monomer composition is charged into the magnesium hydroxide colloid dispersion obtained as described above at room temperature and stirred until the droplets are stabilized, where t-butylperoxy is used as a polymerization initiator. After adding 6 parts of 2-ethylhexanoate (Nippon Yushi Co., Ltd., trade name: Perbutyl O), using an in-line type emulsifying disperser (trade name: Ebara Milder MDN303V), 15, A high-shear stirring was performed at 000 rpm for 10 minutes to form droplets of the polymerizable monomer composition.

  A suspension (polymerizable monomer composition dispersion) in which droplets of the polymerizable monomer composition obtained as described above are dispersed is charged into a reactor equipped with a stirring blade and heated to 90 ° C. Warm to initiate the polymerization reaction. A dispersion obtained by mixing 1 part of methyl methacrylate (polymerizable monomer for shell) and 10 parts of ion-exchanged water in the reactor when the polymerization conversion rate reaches almost 100%, and ion exchange 2,2'-azobis (2-methyl-N- (2-hydroxyethyl) -propionamide) dissolved in 20 parts of water (polymerization initiator for shell, manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086) 0 3 parts were added. Thereafter, the polymerization was continued at 90 ° C. for further 4 hours, followed by polymerization, and then cooled to room temperature to obtain an aqueous dispersion of colored polymer particles.

  Sulfuric acid was added to the aqueous dispersion of colored polymer particles obtained as described above to adjust the pH to 5.8, and acid washing was performed. After dewatering by filtration, 500 parts of ion-exchanged water was added again to make a slurry again, followed by water washing. Thereafter, similarly, dehydration and water washing were repeated several times. After dehydration by filtration, 500 parts of ion-exchanged water was again added to 100 parts of the colored polymer particles and redispersed. At this time, the pH was measured and found to be 6.8. To 100 parts of the colored resin particles, 5 parts of a 2% aqueous solution of potassium laurate (0.1 part in pure content) was added. Further, sulfuric acid was added to adjust the pH to 4.0. It dehydrated by filtration and then dried to obtain dried colored polymer particles. The obtained colored polymer resin particles had a volume average particle size (Dv) of 9.2 μm, a particle size distribution (Dv / Dp) of 1.22, and an average circularity of 0.977.

  100 parts of the colored polymer particles obtained as described above, 1.0 part of silica fine particles hydrophobized with cyclic silazane (product name: TG-820F, manufactured by Cabot Corporation) and silica hydrophobized with amino-modified silicone oil Add 0.6 parts of fine particles (made by Nippon Aerosil Co., Ltd., trade name: “NEA50”), and mix for 6 minutes at a peripheral speed of 30 m / s using a high-speed stirrer (trade name: Henschel mixer). Then, an external addition process was performed to obtain an electrostatic charge image developing toner. Table 1 shows the evaluation results of the toner.

(Example 2)
In Example 1, the same method as in Example 1 was applied except that 5 parts of a 2% aqueous potassium laurate solution (0.1 part in pure content) was added and the pH after addition of sulfuric acid was adjusted to 6.1. A toner for developing a charge image was obtained. Table 1 shows the evaluation results of the toner.

Example 3
In Example 1, instead of 2% potassium laurate aqueous solution, 0.01 part of 0.01% sodium myristate aqueous solution was added (0.1 part in pure content), and sulfuric acid was added to adjust the pH to 4.3. Except for the above, an electrostatic charge image developing toner was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the toner.

Example 4
In Example 1, instead of adding 5 parts (0.1 part pure) of 2% aqueous potassium laurate solution, 25 parts (0.5 parts pure) was added, and pH after adding sulfuric acid. A toner for developing an electrostatic charge image was obtained in the same manner as in Example 1 except that was changed to 3.6. Table 1 shows the evaluation results of the toner.

(Example 5)
In Example 1, instead of adding 5 parts of a 2% aqueous potassium laurate solution (0.1 part pure), 40 parts (0.8 parts pure) was added, and the pH after adding sulfuric acid. The toner for developing an electrostatic charge image was obtained in the same manner as in Example 1 except that the value was 3.5. Table 1 shows the evaluation results of the toner.

(Comparative Example 1)
In Example 1, an electrostatic charge image was obtained in the same manner as in Example 1, except that 2% potassium laurate aqueous solution was not added and sulfuric acid was not added to adjust the pH to 4.0. A developing toner was obtained. Table 1 shows the evaluation results of the toner.

(Comparative Example 2)
In Example 1, an electrostatic charge image developing toner was obtained in the same manner as in Example 1 except that the operation of adding sulfuric acid to adjust the pH to 4.0 was not performed. Table 1 shows the evaluation results of the toner.

(Comparative Example 3)
In Example 1, 0.05 parts of 2-ethyloctadecanoic acid was added to the monomer composition, 2% potassium laurate aqueous solution was not added, and sulfuric acid was added to adjust the pH to 4.0. A toner for developing an electrostatic charge image was obtained in the same manner as in Example 1 except that this operation was not performed. Table 1 shows the evaluation results of the toner.

(Comparative Example 4)
In Comparative Example 3, an electrostatic charge image developing toner was obtained in the same manner as in Comparative Example 3, except that the amount of 2-ethyloctadecanoic acid was changed from 0.05 part to 0.01 part. Table 1 shows the evaluation results of the toner.

From the test results described in Table 1, the following can be understood. However, in Table 1, N. D. Is described below the lower limit of detection, indicating that it was not detected.
The toners of Comparative Example 1 and Comparative Example 2 have printing durability in a normal temperature and normal humidity (N / N) environment and a high temperature and high humidity (H / H) environment because the fatty acid amount A is smaller than that of the present invention. In addition, the toner was inferior in reproducibility of thin lines under normal temperature and normal humidity (N / N) environment.
The toners of Comparative Example 3 and Comparative Example 4 have a higher amount of fatty acid B than the present invention, so that printing durability under normal temperature and normal humidity (N / N) environment and high temperature and high humidity (H / H) environment. In addition, the toner was inferior in reproducibility of thin lines under normal temperature and normal humidity (N / N) environment.

On the other hand, in the toners of Examples 1 to 5, the fatty acid amount A and the fatty acid amount B are set in specific ranges, so that the toner is in a normal temperature and normal humidity (N / N) environment and a high temperature and high humidity (H / H) environment. The toner was excellent in printing durability at low temperature and fine line reproducibility in a normal temperature and normal humidity (N / N) environment.

  The toner for developing an electrostatic charge image of the present invention is excellent in printing durability and fine line reproducibility not only in a normal temperature and normal humidity environment but also in a high temperature and high humidity environment. In the image forming apparatus such as a copying machine, a laser beam printer, and a facsimile machine), the electrostatic latent image formed on the photosensitive member can be used as a developer to make it visible.

Claims (5)

In an electrostatic image developing toner comprising colored polymer particles containing a binder resin, a colorant, a charge control agent, and a release agent,
(1) The fatty acid amount A when the extract obtained by Soxhlet extraction of the toner is measured with a gas chromatograph mass spectrometer is 50 to 6000 ppm based on the toner,
(2) A toner for developing an electrostatic charge image, wherein an amount of fatty acid B measured with a gas chromatograph mass spectrometer is less than 50 ppm based on the toner when an extract obtained by Soxhlet extraction after alkaline washing of the toner is measured.  The electrostatic charge image developing toner according to claim 1, wherein the charge control agent is a charge control resin.   The electrostatic image developing toner according to claim 1, wherein the fatty acid has 8 to 24 carbon atoms.   The electrostatic charge image developing toner according to claim 1, wherein the release agent is a polyfunctional ester compound. In a method for producing a toner for developing an electrostatic image containing colored polymer particles, comprising a step of obtaining an aqueous dispersion of colored polymer particles containing a dispersion stabilizer by a wet method.
(1) A dispersion stabilizer removing step of washing and removing the dispersion stabilizer after obtaining an aqueous dispersion of colored polymer particles,
(2) A water washing step in which after the dispersion stabilizer removing step, dehydration is repeated and dispersed again in water and dehydration is repeated.
(3) The colored polymer particles are separated by filtration after the water washing step, further redispersed in water, and added with an aqueous solution of a fatty acid salt. (4) After the rinsing step, an inorganic acid is added to the aqueous dispersion, A pH adjusting step for lowering the pH further when redispersed in water;
A method for producing a toner for developing an electrostatic charge image.