JP2009244631A - Electrostatic charge image developing toner and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electrostatic charge image developing toner which is superior in printing durability and thin-line reproducibility not only in a normal-temperature, normal-humidity environment, but also in a high-temperature, high-humidity environment. <P>SOLUTION: Disclosed are: the electrostatic charge image developing toner which includes colored polymer particles containing a polymer component, a coloring agent, a charge control a gent, and a releasing agent, the releasing agent being a polyfunctional ester compound and the charge control agent being a charge control resin; and the method of manufacturing the same. Here, when a surface state is analyzed through flight time type secondary ion mass spectrometry using Bi<SB>3</SB>++ as a primary ion, a standardized value of peak intensity of a long-chain alkyl fatty acid residue with C10-25 detected a s a negative secondary ion is 1.5 to 10.0 times as large as a corresponding standardized value measured when acid cleaning is carried out under a condition of pH6.0, and the content of metal atoms is 1 to 150 ppm. <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. For example, in the suspension polymerization method, a polymerizable monomer composition containing a polymerizable monomer, a colorant, and other additive components is subjected to suspension polymerization in an aqueous medium containing a dispersion stabilizer. Thus, a toner (polymerized toner) made of colored polymer particles is manufactured. The colored polymer particles can be core-shell colored polymer particles having a shell formed of a polymer layer on the surface thereof.

  The toner is required to be able to form a high-definition image and to be excellent in printing durability. According to a polymerization method such as a suspension polymerization method, a polymer toner having a small particle diameter, a spherical shape, and a sharp molecular weight distribution can be obtained. Small particle size and spherical polymerized toners are excellent in transferability and dot reproducibility, and can form high-definition images. By devising the composition and structure of the polymerized toner, it is possible to obtain a polymerized toner excellent in printing durability that hardly causes deterioration in image quality such as fogging even if printing is performed continuously.

  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. Regarding the evaluation of whether or not the toner can form a high-definition image, in addition to being able to accurately reproduce the line image, not only in a normal temperature and humidity environment, but also in a high temperature and high humidity environment, When the number of sheets is 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 Examples of Patent Document 1, the polymerizable monomer composition is polymerized in an aqueous medium containing magnesium hydroxide colloid as a dispersion stabilizer, and then the generated colored polymer particles are used as core particles. It is shown that the polymerizable monomer for shell is polymerized in the presence of the core particles to form core-shell type colored polymer particles. In Examples of Patent Document 1, after polymerization, sulfuric acid was added to an aqueous dispersion containing colored polymer particles until pH 6 or lower (near pH 6) to solubilize and remove magnesium hydroxide colloid. It is shown.

  According to the production method disclosed in Patent Document 1, it is possible to obtain a polymerized toner excellent in fine line reproducibility and printing durability. 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. Furthermore, the Example of Patent Document 1 shows only the results of evaluating the fine line reproducibility and printing durability of the obtained polymerized toner in a normal temperature and humidity environment at a temperature of 23 ° C. and a relative humidity of 50%.

  JP-A 2006-276293 (Patent Document 2) proposes a polymerized toner containing a specific polyfunctional ester compound. In an example of Patent Document 2, a polymerizable monomer composition containing a polyfunctional ester compound is subjected to suspension polymerization in an aqueous medium containing a magnesium hydroxide colloid as a dispersion stabilizer, and then the resulting coloring is produced. It is described that the polymerizable monomer for shell is polymerized in the presence of polymer particles to form core-shell type colored polymer particles.

  In Patent Document 2, when a hardly water-soluble inorganic compound colloid is used as a dispersion stabilizer, an acid is added to an aqueous dispersion containing colored polymer particles, and the pH is adjusted to 6.5 or lower. And solubilizing and removing the sparingly water-soluble inorganic compound colloid. In the example of Patent Document 2, it is described that sulfuric acid is added to an aqueous dispersion containing colored polymer particles to adjust the pH to 4.5 or less (near pH 4.5).

  The polymerized toner described in Patent Document 2 is excellent in storability, low-temperature fixability, printing durability under a normal temperature and normal humidity environment, and the like. However, Patent Document 2 does not show evaluation results for fine line reproducibility of the polymerized toner and printing durability in a high temperature and high humidity environment.

  An electrophotographic image forming apparatus is required to stably form a high-definition image regardless of environmental changes. The electrostatic image developing toner used as a developer is required to be able to form a higher definition image and to be more excellent in printing durability. In order to meet the increasing level of demand for electrostatic image developing toners, there is a need for electrostatic image developing toners with superior printing durability and fine line reproducibility, not only in normal temperature and humidity environments but also in high temperature and high humidity environments. Has come to be.

JP 2008-9130 A JP 2006-276293 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 intensive research to solve the above problems, the present inventor has controlled printing durability and fine line reproduction by controlling the composition of the polymerized toner and the surface state of the polymerized toner within a specific selected range. It was found that a toner for developing an electrostatic charge image having remarkably excellent properties can be obtained.

  More specifically, the present inventors polymerize a polymerizable monomer composition containing a polymerizable monomer, a colorant, a charge control agent, and a release agent in an aqueous medium containing a dispersion stabilizer. In the method for producing a toner for developing an electrostatic image comprising colored polymer particles, comprising: 1) a colloid of a poorly water-soluble metal compound as a dispersion stabilizer, 2) a charge control resin as a charge control agent, and 3) release. When a specific polyfunctional ester compound is used as an agent to form colored polymer particles, and then an acid is added to an aqueous dispersion containing the colored polymer particles for acid cleaning, 4) The aqueous dispersion is adjusted so that the pH of the aqueous dispersion is over 2.0 and less than 4.0, and is washed with an acid. If necessary, 5) rinse treatment with an aqueous solution of a long-chain alkyl fatty acid metal salt By carrying out the normal temperature normal humidity ring Under well, even under high temperature and high humidity, it was found that the printing durability and thin line reproducibility can be obtained with toner significantly superior developing electrostatic images.

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, when the surface state analysis of the colored polymer particles was performed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) using Bi ₃ ⁺⁺ as the primary ions, it was detected as negative secondary ions. Colored polymer particles having a normalized value of the peak intensity of a long-chain alkyl fatty acid residue having 10 to 25 carbon atoms, wherein the content of the polyfunctional ester compound is 5 parts by weight with respect to 100 parts by weight of the polymer component. It was found that when acid washing was performed under the condition of pH 6.0, the value was 1.5 to 10.0 times the corresponding normalized value measured by the same method.

  The toner for developing an electrostatic charge image of the present invention is also characterized by a low content of metal atoms derived from a colloid of a poorly water-soluble metal compound or a long-chain alkyl fatty acid metal salt.

  The electrostatic image developing toner of the present invention exhibits excellent toner characteristics by selectively combining a plurality of components as described above, without the need to use expensive materials or complicated processing methods. be able to. According to the production method of the present invention, it is not necessary to employ expensive materials or complicated processing methods, and it is possible to produce a toner for developing an electrostatic image that exhibits excellent toner characteristics. The present invention has been completed based on these findings.

According to the present invention, in an electrostatic image developing toner comprising colored polymer particles containing a polymer component, a colorant, a charge control agent, and a release agent,
(1) The charge control agent is a charge control resin,
(2) The mold release agent is a polyfunctional ester compound of a polyhydric alcohol and a long-chain alkyl fatty acid having 10 to 25 carbon atoms, and the content ratio thereof is 100 parts by weight of the polymer component. 3 to 15 parts by weight,
(3) Carbon detected as negative secondary ions when surface state analysis of the colored polymer particles is performed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) using Bi ₃ ⁺⁺ as primary ions When the normalized value of the peak intensity of the long-chain alkyl fatty acid residue of several tens to 25 is 5 parts by weight with respect to 100 parts by weight of the polymer component, the colored polymer particles have a pH of 6. A value of 1.5 to 10.0 times the corresponding normalized value measured by the same method when acid cleaning is performed under the condition of 0, and
(4) Provided is a toner for developing an electrostatic image, wherein the content of metal atoms is 1 to 150 ppm.

According to the present invention, the step of polymerizing the polymerizable monomer composition containing the polymerizable monomer, the colorant, the charge control agent, and the release agent in the aqueous medium containing the dispersion stabilizer. In a method for producing a toner for developing an electrostatic charge image containing colored polymer particles comprising:
(1) The dispersion stabilizer is a colloid of a poorly water-soluble metal compound,
(2) The charge control agent is a charge control resin,
(3) The polymerizable monomer composition contains, as the release agent, a polyfunctional ester compound of a polyhydric alcohol and a long-chain alkyl fatty acid having 10 to 25 carbon atoms, 100 parts by weight of the polymerizable monomer. With respect to 3 to 15 parts by weight,
(4) After the polymerization, an acid is added to the aqueous dispersion containing the generated colored polymer particles, and an acid washing step for dissolving the colloid of the hardly water-soluble metal compound is arranged, and in the acid washing step, By adding acid, the pH of the aqueous dispersion is adjusted to be in the range of more than 2.0 and less than 4.0, and acid cleaning is performed.
(5) Next, there is provided a method for producing a toner for developing an electrostatic charge image, comprising a washing step of washing the colored polymer particles separated by filtration with water.

  According to the present invention, it is possible to provide a toner for developing an electrostatic charge image that can exhibit excellent 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.

1. Method for producing colored polymer particles (polymerized toner):
The colored polymer particles (polymerized toner) constituting the electrostatic image developing toner of the present invention are a polymerizable monomer, a colorant, a charge control agent, and a release agent in an aqueous medium containing a dispersion stabilizer. It can obtain by the manufacturing method including the process of superposing | polymerizing the polymerizable monomer composition containing this. After the polymerizable monomer composition is subjected to suspension polymerization, the polymerizable monomer for shell may be polymerized in the presence of the generated colored polymer particles to form core-shell type colored polymer particles. . Therefore, the electrostatic image developing toner of the present invention includes those containing core-shell type colored polymer particles.

  In the present invention, a colloid of a poorly water-soluble metal compound is used as a dispersion stabilizer. A positive charge control resin or a negative charge control resin is used as the charge control agent. The charge control resin is preferably a positive charge control resin such as a styrene-acrylate copolymer containing a quaternary ammonium (salt) group. The polymerizable monomer composition contains, as the release agent, a polyfunctional ester compound of a polyhydric alcohol and a long-chain alkyl fatty acid having 10 to 25 carbon atoms with respect to 100 parts by weight of the polymerizable monomer. 3 to 15 parts by weight.

  In the production method of the present invention, after the polymerization, an acid washing step is added in which an acid is added to the aqueous dispersion containing the produced colored polymer particles to dissolve the colloid of the hardly water-soluble metal compound. In this acid cleaning step, acid cleaning is performed by adjusting the pH of the aqueous dispersion to be in the range of more than 2.0 and less than 4.0 by adding acid. Next, a washing step for washing the filtered colored polymer particles with water is arranged. Thereafter, the wet colored polymer particles are dried according to a conventional method.

  In the present invention, in order to further improve printing durability and fine line reproducibility, the colored polymer particles separated by filtration after the washing step are used in an aqueous solution of 1 to 10% by weight of a long-chain alkyl fatty acid metal salt having 8 to 25 carbon atoms. It is desirable to arrange a process of rinsing by the above. After the rinse treatment step, the colored polymer particles in a wet state are dried according to a conventional method.

(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 or a crosslinkable polymer is used together with the 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; And compounds having two vinyl groups such as N, N-divinylaniline and divinyl ether, and compounds having three or more vinyl groups such as pentaerythritol triallyl ether and trimethylolpropane triacrylate.

  The crosslinkable polymer is a polymer having two or more vinyl groups in the polymer. Specific examples thereof include a condensation reaction of a polymer such as polyethylene, polypropylene, polyester or polyethylene glycol having two or more hydroxyl groups in the molecule with an unsaturated carboxylic acid monomer such as acrylic acid or methacrylic acid. The esterified product obtained by can be mentioned.

  These crosslinkable monomers and crosslinkable polymers 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.

  It is preferable to use a macromonomer together with a monovinyl monomer because the balance between storage stability at high temperature and fixability at low temperature is improved. The macromonomer is a macromolecule having a polymerizable carbon-carbon unsaturated double bond at the end of the molecular chain, and is an oligomer or polymer having a number average molecular weight of usually 1,000 to 30,000. When the number average molecular weight is within the above range, it is preferable because the fixability and storability of the polymerized toner can be maintained without impairing the meltability of the macromonomer.

  Examples of the polymerizable carbon-carbon unsaturated double bond at the molecular chain terminal of the macromonomer include an acryloyl group and a methacryloyl group, and a methacryloyl group is preferred from the viewpoint of ease of copolymerization. The macromonomer is preferably one that gives a polymer having a glass transition temperature higher than that of a polymer obtained by polymerizing a monovinyl monomer.

  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, 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, 163, 166, 169, 170, 177, 184, 185, 187, 202, 206, 207, 209, 220, 251 and 254, but are not limited to these. 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 so on.

  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 the monovinyl monomer containing an amino group 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:
In this invention, the polyfunctional ester compound of a polyhydric alcohol and a C10-C25 long-chain alkyl fatty acid is used as a mold release agent. 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, and hexaglycerin octabehenate. 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 Of dipentaerythritol and long-chain alkyl fatty acids such as dipentaerythritol hexapalmitate and dipentaerythritol hexalaurate And the like. 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 large, the printing durability and fine line reproducibility of the toner cannot be improved or tend to decrease even if the acid is washed under a condition of pH less than 4.0.

  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) Lubricant / dispersion aid:
Lubricants such as fatty acid salts of fatty acids such as oleic acid and stearic acid, fatty acids and metals such as Na, K, Ca, Mg, and Zn; silane-based or titanium-based couplings for the purpose of uniform dispersion of colorants, etc. A dispersing aid such as an agent can be contained in the polymerizable monomer. Such lubricants and dispersion aids are usually used at a ratio of about 1/1000 to 1/1 based on the weight of the colorant.

(6) 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 1 ', 3,3'-tetramethylbutyl peroxy-2-ethylhexanoate, t- butyl peroxides of peroxy isobutyrate and the like; and the like. 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.

(7) Molecular weight regulator:
In the polymerization, a molecular weight modifier is preferably used. Examples of molecular weight regulators include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, tetraethylthiuram disulfide, 2,2,4,6,6-pentamethylheptane-4-thiol; And halogenated hydrocarbons such as carbon chloride and carbon tetrabromide. 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.

(8) 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-exchanged 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.

  In the present invention, a colloid of a poorly water-soluble metal compound is used as a dispersion stabilizer. 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 halide salts such as magnesium, aluminum, calcium, manganese, iron, nickel, copper, and tin, sulfate, nitrate, and acetate. 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. The hardly water-soluble metal compound colloid has a number particle size distribution D ₅₀ (50% cumulative value of the number particle size distribution) of 0.5 μm or less and a D ₉₀ (90% cumulative value of the number particle size distribution) of 1 μm or less. It is preferable. When the particle size of the colloid becomes too large, the stability of polymerization is lost, and the storage stability of the toner is lowered.

  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.

(9) Polymerization step:
In the polymerized toner, colored polymer particles in which a polymer component generated by polymerization of a polymerizable monomer becomes a binder resin, and additive components such as a colorant, a charge control resin, and a polyfunctional ester compound are dispersed therein. It is. 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 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 of about 50 to 70 ° C. In the present invention, when the polymer component 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, and meltability during fixing 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. If a shell-forming monomer that forms a polymer having a Tg higher than the Tg of the polymer component constituting the core particle is used, the storage stability (blocking resistance) of the polymerized toner can be improved. it can. On the other hand, by setting the Tg of the polymer component constituting the core particle 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 polymerizable monomer for shell is usually more than 50 ° C. and 120 ° C. or less, preferably more than 60 ° C. and less than 110 ° C., more preferably more than 80 ° C. and less than 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 radical 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- An azo initiator such as [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide] can be used. The amount of the water-soluble polymerization initiator used is usually 0.1 to 50% by weight, preferably 1 to 20% by weight, per 100 parts by weight of the shell polymerizable monomer.

  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) Acid cleaning step:
An acid washing step is provided to dissolve and remove the colloid of the poorly water-soluble metal compound present on the surface of the colored polymer particles that have undergone the polymerization step. 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, in the acid washing step, an acid such as sulfuric acid, hydrochloric acid, or nitric acid is added to an aqueous dispersion containing colored polymer particles produced by polymerization, and the pH of the aqueous dispersion is adjusted to 6.5 or less. Do. The pH of the aqueous dispersion is usually adjusted to a range of 4 to 6.5, and in many cases 4.5 to 6.0. The reason is that in order to dissolve and remove the colloid of the poorly water-soluble metal compound, it is not necessary to make the pH of the aqueous dispersion so low, and if the pH of the aqueous dispersion is too low, the toner characteristics will be affected. This is because there was concern about adverse effects.

  The present inventor has polymerized the polymerizable monomer composition having the specific composition, and then the pH of the aqueous dispersion in the acid washing step is more than 2.0 to less than 4.0, preferably 2.5 to 3.9, more preferably by making it a strong acidic condition in the range of 3.0 to 3.8, the surface properties of the colored polymer particles are modified, and as a result, not only in a normal temperature and humidity environment, It has been found that the printing durability and fine line reproducibility of the toner under a high temperature and high humidity environment are remarkably improved.

  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) Cleaning process:
After the acid washing, the aqueous dispersion containing the colored polymer particles is filtered to separate the colored polymer particles. Next, ion exchange water is newly added to the colored polymer particles, and the slurry is re-slurried (reslurry step), and is again filtered and dehydrated to purify the colored polymer particles.

  This filtration dehydration and reslurry process may be repeated several times as necessary. 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:
In order to further improve the toner characteristics, it is desirable to rinse the colored polymer particles after the washing step. The rinse treatment is performed using a 1 to 10% by weight aqueous solution of a fatty acid metal salt, preferably a 2 to 8% by weight aqueous solution. As a fatty acid metal salt, the salt of a C4-C30 fatty acid and a metal is preferable. 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 fatty acid is preferable. The fatty acid may have a substituent such as a hydroxyl group, an aldehyde group, or an epoxy group in its structure.

  Examples of fatty acids include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitooleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, behenine Examples include acids, erucic acid, hydroxystearic acid, montanic acid, isostearic acid, and epoxy stearic acid. Among these, a saturated fatty acid having 8 to 25 carbon atoms is preferable, and a saturated fatty acid having 14 to 18 carbon atoms is more preferable. These fatty acids can be used alone or in combination of two or more.

  Examples of the metal constituting the fatty acid metal salt include alkalis 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 , Silver and the like. These metals can be used alone or in combination of two or more. Among these, alkali metal salts are preferable.

  When the number of carbon atoms of the fatty acid is too large, the toner surface becomes sticky and the fluidity of the toner is lowered. When the number of carbon atoms of the fatty acid is too small, the toner surface becomes hydrophilic and the charge amount is reduced.

  The colored polymer particles after the rinsing 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 conversion rate of the polymerizable monomer of almost 100% and a very thin shell layer. The content ratio of additive components such as a 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.

The toner of the present invention is detected as negative secondary ions when surface state analysis of the colored polymer particles is performed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) using Bi ₃ ⁺⁺ as primary ions. Colored polymer particles in which the normalized value of the peak intensity of the long-chain alkyl fatty acid residue having 10 to 25 carbon atoms is 5 parts by weight with respect to 100 parts by weight of the polymer component The value is 1.5 to 10.0 times, preferably 2.0 to 5.0 times the corresponding normalized value measured by the same method when acid washing is performed at pH 6.0. Indicates. The normalized value can be calculated by standardizing the intensity ratio with the total detected peak intensity being 1 according to a conventional method.

The surface of the toner (colored polymer particles) is modified by performing acid cleaning under conditions where the pH is more than 2.0 and less than 4.0. Long chain alkyl having 10 to 25 carbon atoms detected as negative secondary ions when surface state analysis of colored polymer particles is performed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) using Bi ₃ ⁺⁺ It is presumed that the fatty acid residue is mainly derived from the polyfunctional ester compound. By appropriately modifying the toner surface, printing durability and fine line reproducibility are remarkably improved not only in a normal temperature and normal humidity environment but also in a high temperature and high humidity environment. This improvement in toner characteristics can be quantified by the peak intensity ratio of long-chain alkyl fatty acid residues having 10 to 25 carbon atoms detected as negative secondary ions.

  If the peak intensity ratio is too low, the effect of improving the printing durability and fine line reproducibility is small, and if it is too large, the same tendency is exhibited. By adjusting the peak intensity ratio within the specific selected range, remarkable printing durability and fine line reproducibility can be exhibited.

  Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is an analysis method for identifying atoms and molecules present on the outermost surface of a sample. The analysis principle is that the sample surface is irradiated with ions such as bismuth (primary ions), the secondary ions released are accelerated at a constant voltage, and the arrival time (flight) by the difference in ion mass Analyze using the difference in time). Extremely sensitive surface analysis is possible.

  Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a mass analysis that utilizes the phenomenon in which components on the surface are repelled by the sputtering phenomenon when primary ions (high-speed ion beams) strike the surface of a solid sample. is there. When the surface of a solid sample placed in an ultra vacuum is irradiated with pulsed primary ions, the secondary ions emitted from the sample surface obtain a constant kinetic energy and are guided to a time-of-flight mass spectrometer. Each secondary ion accelerated with the same energy passes through the analyzer at a velocity depending on the mass, but the distance to the detector is constant, so the time of flight to reach it is a function of mass, By accurately analyzing the time-of-flight distribution, a mass spectrum of secondary ions can be obtained. By analyzing the mass spectrum, organic substances and / or inorganic substances existing on the sample surface can be identified, and knowledge about the abundance can be obtained from the peak intensity.

  The toner of the present invention has a metal atom content of 1 to 150 ppm, preferably 5 to 100 ppm, more preferably 10 to 90 ppm. The toner in which the metal atom content is reduced to 10 to 60 ppm by rinsing is particularly excellent in printing durability and fine line reproducibility.

  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, and strontium titanate. 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 Multisizer (manufactured by Beckman Coulter). It was measured by. The measurement conditions were: Aperture diameter = 100 μm, medium = Isoton II, concentration = 10%, number of measured particles = 100,000.

(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) Fine line reproducibility:
The fine line reproducibility test was performed using a commercially available non-magnetic one-component developing type printer (printing speed: 20 sheets / min). Put the toner to be used for the test into the developing device of the printer, set the copy paper, and leave it in a normal temperature and humidity environment at a temperature of 23 ° C. and a relative humidity of 50% (N / N) for 2 × 2 dot lines ( A line image was continuously formed with a width of about 85 μm, and the density distribution data of the line image was measured for every 500 sheets by a print evaluation system (trade name: RT2000, manufactured by YA-MA). Similarly, the evaluation was performed in a high-temperature and high-humidity environment at a temperature of 30 ° C. and a relative humidity of 80% (H / H).

  In the evaluation, the full width at the half maximum of the density is defined as the line width, and the first line image is reproduced with a difference in the line width of 10 μm or less with reference to the line width of the first line image. The number of sheets that can maintain the line width difference of 10 μm or less was examined up to 10,000 sheets. “> 10000” in the test result indicates that the above-mentioned standard is satisfied even if 10,000 line images are printed continuously.

(4) Printing durability:
The printing durability test was performed using a commercially available non-magnetic one-component developing type printer (printing speed: 20 sheets / min). Put the toner to be used for the test into the developing device of the printer, set the copy paper, leave it at room temperature and humidity in a temperature of 23 ° C and a relative humidity of 50% (N / N) for a day and night, and continuously at 1% print density. Printing was performed, and printing density and fogging were measured every 500 sheets.

  The print density was measured by a method of performing solid black print (100% print density) and measuring it with a reflective image density measuring machine.

  The fog was measured as follows. White solid printing (0% printing density) is performed, the printer is stopped halfway, and the toner in the non-image area on the developed photoreceptor is coated with an adhesive tape (manufactured by Sumitomo 3M, trade name “Scotch Mending Tape 810-”). 3-18 "). This adhesive tape was affixed to a new printing paper, and the whiteness (A) was measured with a whiteness meter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name “NDW-1D”). As a reference (reference sample), an unused adhesive tape was attached to the printing paper, and the whiteness (B) was measured in the same manner. The difference in whiteness (B−A) was defined as the fog value (%). Smaller values indicate less fog and better image quality. Similarly, the evaluation was performed in a high-temperature and high-humidity environment at a temperature of 30 ° C. and a relative humidity of 80% (H / H).

  In the evaluation, the number of continuous prints that can maintain an image quality in which the print density when black solid printing is 1.3 or more and the fog value when white solid printing is 10% or less can be maintained is 10,000. Up to one sheet was tested. “> 10000” in the test result indicates that the above-mentioned standard is satisfied even if 10,000 sheets are continuously printed.

(5) Time-of-flight secondary ion mass spectrometry (TOF-SIMS):
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was performed using TOF-SIMS 5 (manufactured by ION-TOF) as a measuring device. Measurement conditions are as follows: primary ion species = Bi ₃ ⁺⁺ , primary ion energy = 25 kV, pulse width = 7.0 ns, bunching = present, charging neutralization = present, measurement vacuum = 4 × 10 ⁻⁷ Pa, secondary The ion polarity was negative, the number of scans was 32, the number of pixels was 128, and the subsequent acceleration was 10 kV.

  The negative secondary ion spectrum obtained by the measurement is analyzed, and the normalized value of the peak intensity of the long-chain alkyl fatty acid residue having 10 to 25 carbon atoms among the negative secondary ions released from the sample surface is calculated. The content ratio of the polyfunctional ester compound is measured when acid washing is performed under the condition of pH 6.0 for 5 parts by weight of the colored polymer particles with respect to 100 parts by weight of the polymer component (polymerizable monomer). The corresponding normalized value (toner of Comparative Example 1) is calculated, and this normalized value is used as a reference. The magnification of the normalized value of the negative secondary ion of each sample with respect to the standardized value serving as a reference is calculated.

In Examples 1 to 3 and Comparative Examples 1 to 3, the peak of a myristic acid residue (C ₁₃ H ₂₈ COO ⁻ ) was detected as a negative secondary ion. With the normalized value of the peak intensity of the negative secondary ions of the toner of Comparative Example 1 being 1.0, the peak intensity ratio of the corresponding normalized values of other toners was obtained.

(6) Metal atom content:
The content of metal atoms contained in the colored polymer particles was measured by the following procedure.
A sample (about 0.2 g of toner) is weighed in a heat-resistant container, and after adding concentrated sulfuric acid until the organic matter in the sample is carbonized, wet decomposition is performed to remove the carbonized organic matter as carbon dioxide by adding nitric acid. It was. The wet-decomposed sample was transferred to a 10 ml volumetric flask and co-washed with ion exchanged water, and the volumetric flask was adjusted to a constant volume of 10 ml to prepare a test solution for measurement. Using the ICP-AES (Inductively Coupled Plasma Emission Spectroscopy) apparatus (manufactured by Seiko Instruments Inc., product surface “SPS-5100”), the adjusted test solution was prepared in advance by measuring the content of metal atoms. The amount of metal atoms contained in the colored polymer particles was calculated from the calibration curve.

[Example 1]
As monovinyl monomers, 80.5 parts of styrene and 19.5 parts of n-butyl acrylate (Tg of copolymer obtained by copolymerizing these monomers = 55 ° C.), polymethacrylate macromonomer ( Toa Gosei Chemical Co., Ltd., trade name “AA6”, Tg = 94 ° C. 0.3 part, divinylbenzene 0.5 part, t-dodecyl mercaptan 1.2 part, and carbon black (Mitsubishi Chemical Corporation, trade name "# 25B") 7 parts were mixed and wet pulverized using a media type wet pulverizer. Thereafter, 1 part of a charge control resin (trade name “Acrybase FCA-207P” manufactured by Fujikura Kasei Co., Ltd .; styrene-acrylate copolymer having a quaternary ammonium salt-containing monomer unit of 2% by weight) and dipentaerythritol hexamilli. 5 parts of State (trade name “W663” manufactured by NOF Corporation) were added and mixed to obtain a polymerizable monomer composition.

To an aqueous solution in which 10.2 parts of magnesium chloride are dissolved in 250 parts of ion-exchanged water, an aqueous solution in which 6.2 parts of sodium hydroxide is dissolved in 50 parts of ion-exchanged water is gradually added with stirring to obtain a magnesium hydroxide colloid. A dispersion was produced. When the particle size distribution of the colloid was measured using a SALD particle size distribution analyzer (manufactured by Shimadzu Corporation), D ₅₀ (50% cumulative value of the number particle size distribution) was 0.36 μm, and D ₉₀ (number particle) 90% cumulative value of the diameter distribution) was 0.80 μm.

  The polymerizable monomer composition was put into a stirring tank containing the magnesium hydroxide colloid dispersion and stirred until the droplets were stabilized. There, 5 parts of t-butyl peroxy-isobutyrate (manufactured by NOF Corporation, trade name “Perbutyl IB”) was added as a polymerization initiator. Subsequently, the obtained dispersion liquid is circulated through an in-line type disperser (trade name “Ebara Milder MDN303V”, manufactured by Ebara Seisakusho Co., Ltd.) operating at a rotational speed of 15,000 rpm, and the stirring tank, and a polymerizable monomer composition. Droplets were formed.

  One part of sodium tetraborate decahydrate was added to the magnesium hydroxide colloidal dispersion in which the polymerizable monomer composition in which droplets were formed was dispersed, and the mixture was placed in a reactor equipped with a stirring blade. The reactor was heated to 85 ° C. to conduct a polymerization reaction. After the polymerization conversion reached almost 100%, 2,2′-azobis [2-methyl-N- (2- Hydroxyethyl) -propionamide] (trade name “VA-086” manufactured by Wako Pure Chemical Industries, Ltd.) was added to the reactor. Furthermore, after continuing the polymerization for 4 hours, the reaction was stopped by cooling with water to obtain an aqueous dispersion of colored polymer particles of core-shell type.

  While stirring the aqueous dispersion of colored polymer particles obtained above, sulfuric acid was added to adjust the pH of the aqueous dispersion to 3.8. Acid cleaning by this method was performed at a temperature of 25 ° C. for 10 minutes. Next, the aqueous dispersion was filtered, and again added to 400 parts of ion-exchanged water to 100 parts of the colored polymer particles, re-dispersed and then filtered. Furthermore, the colored polymer particles were rinsed using 100 parts of 5% potassium myristate aqueous solution with respect to 100 parts of the colored polymer particles. Thereafter, the colored polymer particles were dried.

  100 parts of the colored polymer particles thus obtained were subjected to 1 part of silica fine particles hydrophobized with cyclic silazane (product name “TG820F” manufactured by Cabot) and silica fine particles hydrophobized with amino-modified silicone oil ( 1 part of a product manufactured by Nippon Aerosil Co., Ltd. (product name “NEA50”) was added and mixed (externally added) using a Henschel mixer to obtain a toner for developing an electrostatic image (nonmagnetic one-component developer). The results are shown in Table 1.

[Example 2]
In Example 1, an electrostatic charge image developing toner was obtained in the same manner as in Example 1 except that it was not rinsed with an aqueous potassium myristate solution. The results are shown in Table 1.

[Example 3]
In Example 2, an electrostatic charge image developing toner was obtained in the same manner as in Example 2 except that the amount of dipentaerythritol hexamyristate was changed from 5 parts to 10 parts. The results are shown in Table 1.

[Comparative Example 1]
In Example 2, an electrostatic charge image developing toner was obtained in the same manner as in Example 2 except that the pH of the aqueous dispersion in the step of dissolving and removing the hardly water-soluble metal colloid was 6.0. The results are shown in Table 1.

[Comparative Example 2]
In Example 2, an electrostatic charge image developing toner was obtained in the same manner as in Example 2 except that the amount of dipentaerythritol hexamyristate was changed from 5 parts to 1 part. The results are shown in Table 1.

[Comparative Example 3]
In Example 2, an electrostatic image developing toner was obtained in the same manner as in Example 2 except that the amount of dipentaerythritol hexamyristate was changed from 5 parts to 30 parts. The results are shown in Table 1.

(footnote)
(1) n-BuA: n-butyl acrylate (2) DVB: divinylbenzene (3) t-DMC: t-dodecyl mercaptan (4) CB # 25B: carbon black # 25
(5) CCR: Charge control resin (manufactured by Fujikura Kasei Co., Ltd., trade name “Acrybase FCA-207P”)
(6) DPEHM: Dipentaerythritol hexamyristate (7) MMA: Methyl methacrylate

  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 polymer component, a colorant, a charge control agent, and a release agent,
(1) The charge control agent is a charge control resin,
(2) The mold release agent is a polyfunctional ester compound of a polyhydric alcohol and a long-chain alkyl fatty acid having 10 to 25 carbon atoms, and the content ratio thereof is 100 parts by weight of the polymer component. 3 to 15 parts by weight,
(3) Carbon detected as negative secondary ions when surface state analysis of the colored polymer particles is performed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) using Bi ₃ ⁺⁺ as primary ions When the normalized value of the peak intensity of the long-chain alkyl fatty acid residue of several tens to 25 is 5 parts by weight with respect to 100 parts by weight of the polymer component, the colored polymer particles have a pH of 6. A value of 1.5 to 10.0 times the corresponding normalized value measured by the same method when acid cleaning is performed under the condition of 0, and
(4) A toner for developing electrostatic images, wherein the content of metal atoms is 1-150 ppm.   The electrostatic charge image developing toner according to claim 1, wherein the charge control resin is a positively chargeable charge control resin. Contains colored polymer particles including a step of polymerizing a polymerizable monomer composition containing a polymerizable monomer, a colorant, a charge control agent, and a release agent in an aqueous medium containing a dispersion stabilizer In the method for producing an electrostatic charge image developing toner,
(1) The dispersion stabilizer is a colloid of a poorly water-soluble metal compound,
(2) The charge control agent is a charge control resin,
(3) The polymerizable monomer composition contains, as the release agent, a polyfunctional ester compound of a polyhydric alcohol and a long-chain alkyl fatty acid having 10 to 25 carbon atoms, 100 parts by weight of the polymerizable monomer. With respect to 3 to 15 parts by weight,
(4) After the polymerization, an acid is added to the aqueous dispersion containing the generated colored polymer particles, and an acid washing step for dissolving the colloid of the hardly water-soluble metal compound is arranged, and in the acid washing step, By adding acid, the pH of the aqueous dispersion is adjusted to be in the range of more than 2.0 and less than 4.0, and acid cleaning is performed.
(5) Next, a method for producing an electrostatic charge image developing toner, comprising a washing step of washing the colored polymer particles separated by filtration with water.   The method according to claim 3, wherein the charge control resin is a positively chargeable charge control resin.   The manufacturing method of Claim 3 or 4 which arrange | positions the rinse process process which processes the colored polymer particle separated by filtration with the 1-10 weight% aqueous solution of a C8-C25 long-chain alkyl fatty acid metal salt after a washing | cleaning process. .